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Sample records for braquiterapia endoluminal hdr

  1. Simultaneous radiochemotherapy and endoluminal HDR brachytherapy in esophageal cancer; Simultane Radiochemotherapie mit intraluminaler HDR-Brachytherapie des Oesophaguskarzinoms

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    Patonay, P.; Naszaly, A.; Mayer, A. [Hauptstaedtisches Zentrum fuer Radioonkologie und Strahlentherapie, Budapest (Hungary)

    2007-02-15

    Purpose: to study efficacy and toxicity of radiochemotherapy in esophageal cancer including initial endoluminal high-dose-rate brachytherapy (HDR-BT). Patients and methods: between 01/1995 and 06/2005, 61 patients with esophageal cancer were treated preoperatively with definitive and palliative intent. Treatment started with intraluminal HDR-BT for recanalization of the esophagus (single fraction size of 8 Gy in 0.5 cm depth, three times, q7d) followed by external-beam radiation therapy (50 Gy total dose, 5 x 2 Gy/week, 25 fractions in 5 weeks). Chemotherapy was started simultaneously with external irradiation (three courses of cisplatin and 5-fluorouracil, q21d). Results: swallowing function improved in 55/61 patients (dysphagia classification according to the RTOG), and worsened in 6/61 patients, respectively. Median duration of symptomatic improvement was 11 months, median follow-up 12 months (range 3-68 months). Following simultaneous radiochemotherapy, tumor resectability was achieved in 7/25 patients of the neoadjuvant group, and the histological specimen showed complete remission in 6/7 patients. Conclusion: these results indicate a favorable effect of simultaneous radiochemotherapy starting with endoluminal HDR-after-loading-(AL-)BT in esophageal cancer. (orig.)

  2. Braquiterapia intersticial de alta tasa de rescate en cáncer cabeza cuello previamente radiado High-dose-rate (HDR brachytherapy in previously irradiated recurrent head and neck cancer

    Directory of Open Access Journals (Sweden)

    Lucía Gutiérrez-Bayard

    2011-09-01

    Full Text Available A pesar de los avances en el tratamiento de cáncer de cabeza y cuello (CCC, el 15-50% de los pacientes presentan recurrencia locorregional. Para los pacientes que presentan enfermedad localmente recurrente o un segundo tumor primario en un campo previamente irradiado, las opciones terapéuticas de rescate son limitadas, siendo la resección quirúrgica con intención curativa la opción de elección para los pacientes con enfermedad limitada. Reirradiación con o sin la adición de quimioterapia puede ser una buena opción, obteniendo en pacientes seleccionados supervivencia a largo plazo. La braquiterapia de alta tasa de dosis (HDRBT puede jugar un papel importante en el tratamiento de rescate en tumores de cabeza y cuello recurrentes. Presentamos un paciente de 56 años diagnosticado de cáncer de lengua sometido a cirugía y radioterapia externa adyuvante, y recurrencia metastásica ganglionar cervical contralateral a los 18 meses. Recibió tratamiento multidisciplinar con quimioterapia, cirugía y braquiterapia intersticial.Despite advances in the treatment of head and neck cancer (HNC, 15-50% of patients present locoregional disease recurrence. The therapeutic options are limited for patients who present locally recurrent disease or a second primary tumor in a previously irradiated field. Surgical salvage with curative intent is the preferred option for patients with limited-volume disease. Re-irradiation with or without the addition of chemotherapy may hold promise for long-term survival for selected patients. High-dose-rate (HDR brachytherapy can play an important role in the salvage treatment of previously irradiated recurrent head and neck cancer. The case reported was a 56-year old man diagnosed of tongue cancer who presented recurrent metastatic contralateral cervical node 1.5 years after radical treatment with surgery and adjuvant external radiotherapy. He received multidisciplinary treatment with chemotherapy, surgery and HDR

  3. Study of the workload to be applied in the shielding calculation in HDR brachytherapy facilities with IR-192; Estudio de la carga de trabajo a aplicar en el calculo de blindajes en instalaciones de braquiterapia HDR con IR-192

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    Pujades-Clamarchirant, M. C.; Perez-Calatayud, J.; Ballester, F.; Gimeno, J.; Granero, D.; Camacho, C.; Carmona, V.; Lliso, F.; Vijande, J.

    2011-07-01

    The design of shielding facilities high rate brachytherapy (HDR) requires an estimate of the workload (w) . The aim of this study was to evaluate the W typical service HDR BT with a high number of applications and their impact on the final thickness the shielding of the room. To do this, a review of patients treated in our center HDR W has been evaluated and studied their impact on the shielding design of the facility.

  4. Evaluation of the Kerma at the entrance of the labyrin thin in facilities with Co-60 HDR brachytherapy; Evaluacion del Kerma en la entrada del laberinto en instalaciones de braquiterapia de HDR con Co-60

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    Pujades, M. C.; Granero, D.; Ballester, F.; Perez-Calatayud, J.; Vijande, J.

    2013-07-01

    The purpose of this study is to evaluate the kerma's collision at the entrance of the labyrinth adapting the methodology of the NCRP-151 to a bunker of brachytherapy with Co-60, similar to the one carried out in a previous work with HDR Ir-192. To validate the result is simulated using techniques Monte Carlo (MC) two typical designs of HDR with Co-60 bunker. (Author)

  5. Endoluminal occlusion devices: technology update

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    Zander T

    2014-12-01

    Full Text Available Tobias Zander,1 Samantha Medina,1 Guillermo Montes,1 Lourdes Nuñez-Atahualpa,1 Michel Valdes,1 Manuel Maynar1,2 1Endoluminal/Vascular Department, Hospiten Hospital Group, Santa Cruz de Tenerife, 2University of Las Palmas de Gran Canarias, Las Palmas, Canary Island, Spain Abstract: Endoluminal occlusion has been performed since the early beginning of interventional radiology. Over recent decades, major technological advances have improved the techniques used and different devices have been developed for changing conditions. Most of these occlusion devices have been implemented in the vascular territory. Early embolization materials included glass particles, hot contrast, paraffin, fibrin, and tissue fragments such as muscle fibers and blood clots; today, occlusion materials include metallic devices, particles, and liquid materials, which can be indicated for proximal or distal occlusion, high-flow and low-flow situations, and in large-caliber and small-caliber vessels, based on need. Technological progress has led to a decreased size of delivery catheters, and an increase in safety due to release systems that permit the withdrawing and replacement of embolization material. Furthermore, bioactive embolization materials have been developed to increase the efficacy of embolization or the biological effect of medication. Finally, materials have been modified for changing indications. Intravascular stents were initially developed to keep an artery open; however, by adding a covering membrane, these stents can be used to occlude the wall of a vessel or other endoluminal structures. This article gives an overview of the devices most utilized for occlusion of endoluminal structures, as well as their major purpose in the endovascular territory. Keywords: embolization, endovascular treatment, occlusion devices, hemorrhage, aneurysm, fistula

  6. Endoluminal MR imaging of anorectal diseases

    NARCIS (Netherlands)

    Stoker, J.; Rociu, E.

    1999-01-01

    Endoluminal magnetic resonance imaging (MRI) has become an important technique in the diagnostic work-up of patients with anorectal diseases. The high spatial resolution of endoluminal MRI gives a detailed demonstration of the anal and rectal anatomy and pathology. This technique has been

  7. Endoluminal treatment of aortic dissection

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    Chavan, Ajay; Lotz, Joachim; Galanski, Michael [Department of Diagnostic Radiology, Hannover Medical School, Carl Neuberg Strasse 1, 30625, Hannover (Germany); Oelert, Frank; Haverich, Axel; Karck, Matthias [Department of Thoracic and Cardiovascular Surgery, Hannover Medical School, Carl Neuberg Strasse 1, 30625, Hannover (Germany)

    2003-11-01

    Aortic dissection is most often a catastrophic medical emergency which, if untreated, can be potentially fatal. The intention of therapy in patients with aortic dissection is to prevent aortic rupture or aneurysm formation as well as to relieve branch vessel ischaemia. Patients with aortic dissection are often poor candidates for anaesthesia and surgery and the surgical procedure itself is challenging requiring thoracotomy, aortic cross clamping, blood transfusion as well as prolonged hospital stay in some cases. Operative mortality is especially high in patients with critical mesenteric or renal ischaemia. The past decade has experienced the emergence of a number of interventional radiological or minimally invasive techniques which have significantly improved the management of patients with aortic dissection. These include stent grafting for entry site closure to prevent aneurysmatic widening of the false lumen as well as percutaneous techniques such as balloon fenestration of the intimal flap and aortic true lumen stenting to alleviate branch vessel ischaemia. False lumen thrombosis following entry closure with stent grafts has been observed in 86-100% of patients, whereas percutaneous interventions are able to effectively relieve organ ischaemia in approximately 90% of the cases. In the years to come, it is to be expected that these endoluminal techniques will become the method of choice for treating most type-B dissections and will assist in significantly reducing the number of open surgical procedures required for type-A dissections. The intention of this article is to provide an overview of the current status of these endoluminal techniques based on our own experience as well as on a review of the relevant literature. (orig.)

  8. Braquiterapia en el cáncer de labio

    OpenAIRE

    Rovirosa Casino, Angeles; Planas Toledano, Isabel; Ferre Jorge, Jorge; Oliva Díez, José María; Conill Llobet, Carlos

    2006-01-01

    El cáncer de labio es de los más prevalentes entre los tumores cutáneos de cabeza y cuello. Las características del tumor, por su crecimiento exofítico en una zona de fácil acceso visual, permite un diagnóstico en estadios incipientes y, por tanto, un mejor pronóstico con los actuales tratamientos. En estadios iniciales se puede realizar tratamiento con cirugía o braquiterapia, siendo los resultados similares en cuanto al control local; sin embargo la braquiterapia ofrece mejores resultados e...

  9. Tone compatibility between HDR displays

    Science.gov (United States)

    Bist, Cambodge; Cozot, Rémi; Madec, Gérard; Ducloux, Xavier

    2016-09-01

    High Dynamic Range (HDR) is the latest trend in television technology and we expect an in ux of HDR capable consumer TVs in the market. Initial HDR consumer displays will operate on a peak brightness of about 500-1000 nits while in the coming years display peak brightness is expected to go beyond 1000 nits. However, professionally graded HDR content can range from 1000 to 4000 nits. As with Standard Dynamic Range (SDR) content, we can expect HDR content to be available in variety of lighting styles such as low key, medium key and high key video. This raises concerns over tone-compatibility between HDR displays especially when adapting to various lighting styles. It is expected that dynamic range adaptation between HDR displays uses similar techniques as found with tone mapping and tone expansion operators. In this paper, we survey simple tone mapping methods of 4000 nits color-graded HDR content for 1000 nits HDR displays. We also investigate tone expansion strategies when HDR content graded in 1000 nits is displayed on 4000 nits HDR monitors. We conclude that the best tone reproduction technique between HDR displays strongly depends on the lighting style of the content.

  10. Antireflux Endoluminal Therapies: Past and Present

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    Kuo Chao Yew

    2013-01-01

    Full Text Available The basic principle of antireflux procedures employing endoscopic intervention aims to create a mechanical barrier to prevent primary pathophysiology in gastroesophageal reflux disease (GERD. We review, highlight, and discuss the past and present status of endoluminal therapy. Currently, there are 3 commonly employed anti-reflux endoluminal procedures: fundoplication or suturing techniques (EndoCinch, NDO, and EsophyX, intramural injection or implant techniques (enhancing lower esophageal sphincter (LES volume and/or strengthening compliance of the LES-Enteryx and Gatekeeper, and radiofrequency ablation of LES and cardia. EndoCinch plication requires further study and modification of technique before it can be recommended because of durability issues. Esophynx, the transoral incisionless fundoplication, may reduce hiatal hernias and increase LES length. Preliminary studies have shown promising reduction in symptoms and medication use but evidence concerning safety and long-term durability is still pending. The safety issue with injection technique is the main concern as evident from the incidences of implant withdrawals after reported major adverse events. Future research with cautious monitoring is required before any new implant material can be recommended for commercial application. Radiofrequency ablation therapy is regaining popularity in treating refractory symptoms despite PPI use due to improved efficacy, durability, and safety after years of refinement of protocol.

  11. Aortic dissection - when classical surgical approach, when endoluminal repair?; Die Aortendissektion - Wann operieren, wann endoluminal therapieren?

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    Richter, G.M.; Hansmann, J. [Heidelberg Univ. (Germany). Abt. Radiodiagnostik; Allenberg, J.R.; Schumacher, H. [Heidelberg Univ. (Germany). Chirurgische Universitaetsklinik, Abt. Gefaesschirurgie; Vahl, C.; Hagl, S. [Heidelberg Univ. (Germany). Chirurgische Universitaetsklinik, Abt. Herzchirurgie

    2001-08-01

    Goal. To demonstrate the Heidelberg results of the previous 2 years in patients referred for acute aortic dissection. Material and Methods. 93 patients referred for acute aortic dissection were treated by cardiac surgery, vascular surgery and interventional radiology according to a novel therapeutic algorithm including stent-grafts and combined open and interventional procedures and conservative medical therapy when no malperfusion syndrome was present or patients were considered prohibitive for even minor surgical procedures. Stent-graft placements were done assisted by short term cardiac arrest to facilitate correct device deployment. Results. 36 patients presented with type A and the other 57 with type B dissection. 32 of the A patients were operated and 20 of the B patients, respectively. 12 patients with B dissection were treated with stent-grafts. 3 required additional interventional therapy for organ malperfusion. The mortality was 0% in these 12 patients. The overall mortality rate in the A group was close to 40% mainly as a result of postoperative organ malperfusion while it was 15% in the B group. In both groups mortality was highest in the respective untreated patient subgroup (3/4 and 8/37, respectively). The main mortality factor was visceral (mesenteric or liver) ischemia. Paraplegic complications occured in neither group. In 4 patients a combined approach applying cardiac surgery of the ascending aorta and endluminal stent-graft placement for the residual B dissection was successfully performed. In one patient this was done simultaneously. Discussion. Acute aortic dissection of type A with or without valve involvement, coronary artery ischemia can be treated with high technical success rates. However, remaining distal aortic dissection associated with true lumen collapse and organ malperfusion is the main causative factor for clinical failures. Successful combination of open proximal aortic surgery with endoluminal treatment of residual B dissection

  12. Endoluminal perforation of a magnetic antireflux device.

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    Bauer, Margit; Meining, Alexander; Kranzfelder, Michael; Jell, Alissa; Schirren, Rebekka; Wilhelm, Dirk; Friess, Helmut; Feussner, Hubertus

    2015-12-01

    The history of surgical antireflux treatment is coined by the search for better alternatives to Nissen fundoplication. Implantable devices are one option, beginning with the "Angelchik" prosthesis 30 years ago. However, this procedure was left soon because of the high rate of foreign body connected problems (migration, perforation). A modern approach is a magnetic sphincter augmentation device (LINX Reflux Management System, Torax Medical, Shoreview, MN, USA), a magnetic chain which is implanted laparoscopically. Advantages reported are simplicity to apply and good results in reflux control, with up to now only rare complication rates as reported in the literature (Lipham et al. in Dis Esophagus, 2014). We report one case of erosion of the esophagus by a LINX system resulting in severe dysphagia. A complete endoluminal removal could be achieved by a prototype OTSC-clip remover. Complete remission could be achieved. The technique is presented in detail (video). In principle, total endoscopic removal of the LINX device is feasible in case of major erosion.

  13. Endoluminal brachytherapy for recurrent laryngeal carcinoma

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    Latham, M.M. [Sir Charles Gairdner Hospital, Perth, WA, (Australia). Dept of Radiotherapy; Smart, G.P.; Hedland-Thomas, B. [Royal Perth Hospital, WA, (Australia). Dept of Medical Physics; Harper, C.S. [Royal Perth Hospital, WA (Australia). Radiation Oncology Centre

    1997-11-01

    Early-stage squamous cell carcinoma of the larynx is usually treated with local field radiotherapy. Surgery is used for salvage following recurrence. Further recurrences present a more difficult therapeutic problem which requires individualized management. The aims of local control, survival, maintenance of function and minimizing side effects all need to be balanced according to the site and extent of disease. The present case study looks at the management of a 54-year-old man with multiple recurrences from a squamous cell carcinoma of the larynx. It describes a technique of endoluminal brachytherapy using an iridium-192 wire spiraled around the outer part of a tracheotomy tube that achieves good local control while enabling self-insertion and self-cleaning during the procedure. The dose given was 2500 cGy at 5 mm over 25.2 h and was achieved with minimal early or delayed side effects. The patient had no further symptoms relating to the stomal recurrence until his death from metastatic disease 6 months later. (authors). 8 refs., 3 figs.

  14. Tratamiento del cáncer de labio mediante braquiterapia de alta tasa de dosis.

    OpenAIRE

    Finestres Zubeldia, Fernando

    2003-01-01

    OBJETIVOS: Valorar la utilidad del tratamiento en estadios I y II de cáncer de labio mediante braquiterapia de alta tasa de dosis (ATD) y el empleo de nuevos aplicadores cutáneos. Establecer la eficacia y morbilidad de las dosis terapéuticas administradasMATERIAL Y MÉTODOS: Desde febrero de 1992 hasta diciembre de 2000, fecha en que se cierra el estudio, un total de 56 pacientes con cáncer de labio (49 T1N0M0 y 7 T2N0M0) han sido tratados mediante braquiterapia de ATD con moldes personalizado...

  15. Stomach Simulator for Analysis and Validation of Surgical Endoluminal Robots

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    Sara Condino

    2011-01-01

    Full Text Available A testing environment that imitates gastric geometry and contractile activity is necessary to analyse and validate endoluminal surgical robotic devices developed for gastric pathologies. To achieve this goal, a silicone stomach model and a mechanical setup to simulate gastric contractile motion were designed and fabricated. The developed stomach simulator was validated and its usefulness was demonstrated by means of internal pressure measurements and self-assembly tests of mock-ups of capsule devices. The results demonstrated that the stomach simulator is helpful for quantitative evaluation of endoluminal robotic devices before in-vitro/in-vivo experiments.

  16. The history of HDR research and development

    Energy Technology Data Exchange (ETDEWEB)

    Duchane, D.

    1998-12-31

    An energy source rivaling the sun exists in the form of the heat emanating from the interior of the earth. Although limited quantities of this geothermal energy are produced today by bringing natural hot fluids to the surface, most of the earth`s heat is trapped in hot dry rock (HDR). The application of hydraulic fracturing technology to tap this vast HDR resource was pioneered by Los Alamos National Laboratory beginning in 1970. Since that time, engineered geothermal reservoirs have been constructed and operated at numerous locations around the world. Major work at the US HDR facility at Fenton Hill, NM, and at the British HDR site in Cornwall, UK, has been completed, but advanced HDR field work continues at two sites on the island of Honshu in Japan and at Soultz in northeastern France. In addition, plans are currently being completed for the construction of an HDR system on the continent of Australia. Over the past three decades the worldwide research and development effort has taken HDR from its early conceptual stage to its present state as a demonstrated technology that is on the verge of becoming commercially feasible. Extended flow tests in the United States, Japan, and Europe have proven that sustained operation of HDR reservoirs is possible. In support of these field tests, an international body of scientists and engineers have pursued a variety of innovative approaches for assessing HDR resources, constructing and characterizing engineered geothermal reservoirs, and operating HDR systems. Taken together, these developments form a strong base upon which to build the practical HDR systems that will provide clean energy for the world in the 21st century.

  17. Determination of the dose around an ovoid for treatments in intracavitary brachytherapy Hdr; Determinacion de la dosis alrededor de un ovoide para tratamientos en braquiterapia intracavitaria HDR

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    Rivera M, T. [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Legaria No. 694, Col. Irrigacion, 11500 Mexico D. F. (Mexico); Velasco V, R. A. E. [Hospital Central Militar, Periferico y Ejercito Nacional s/n, Lomas de Sotelo, 11200 Mexico D. F. (Mexico); Serrano F, A. K. [Hospital Juarez de Mexico, Av. Instituto Politecnico Nacional No. 5190, Col. Magdalena de las Salinas, 03220 Mexico D. F. (Mexico); Azorin N, J., E-mail: trivera@ipn.m [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Av. San Rafael Atlixco No. 186, Col. Vicentina, 09340 Mexico D. F. (Mexico)

    2010-09-15

    On this work the results of the dosimetric measurements are presented around an ovoid of 2 cm diameter. The measurements were carried out using a water mannequin, an ovoid, a radiation gamma source of {sup 192}Ir and thermoluminescent dosemeters. The dosimetry was realized in the direction of the rectum and bladder. To know the effect of the shielding of the devices type Manchester in the dose, the thermoluminescent dosemeters were irradiated to a radiation gamma source of {sup 192}Ir contained in the Gamma med Plus equipment. The planning was realized normalizing the calculation to 2.5 cm from the applicator center on the transverse plane (2.5, 0, 0). The results show that the dose distribution for an ovoid without shielding is more uniform in the transversal plane to the source axis. The results were compared with the calculated results by means of the planning system BrachyVision. While the absorbed dose distribution around an ovoid with shielding is completely anisotropic. This anisotropic is due to the shielding. (Author)

  18. A Novel Device for Measuring Forces in Endoluminal Procedures

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    Tommaso Ranzani

    2015-08-01

    Full Text Available In this paper a simple but effective measuring system for endoluminal procedures is presented. The device allows measuring forces during the endoluminal manipulation of tissues with a standard surgical instrument for laparoscopic procedures. The force measurement is performed by recording both the forces applied directly by the surgeon at the instrument handle and the reaction forces on the access port. The measuring system was used to measure the forces necessary for appropriate surgical manipulation of tissues during transanal endoscopic microsurgery (TEM. Ex-vivo and in-vivo measurements were performed, reported and discussed. The obtained data can be used for developing and appropriately dimensioning novel dedicated instrumentation for TEM procedures.

  19. Bariatric Surgery and Endoluminal Procedures: IFSO Worldwide Survey 2014.

    Science.gov (United States)

    Angrisani, L; Santonicola, A; Iovino, P; Vitiello, A; Zundel, N; Buchwald, H; Scopinaro, N

    2017-09-01

    Several bariatric surgery worldwide surveys have been previously published to illustrate the evolution of bariatric surgery in the last decades. The aim of this survey is to report an updated overview of all bariatric procedures performed in 2014.For the first time, a special section on endoluminal techniques was added. The 2014 International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO) survey form evaluating the number and the type of surgical and endoluminal bariatric procedures was emailed to all IFSO societies. Trend analyses from 2011 to 2014 were also performed. There were 56/60 (93.3%) responders. The total number of bariatric/metabolic procedures performed in 2014 consisted of 579,517 (97.6%) surgical operations and 14,725 (2.4%) endoluminal procedures. The most commonly performed procedure in the world was sleeve gastrectomy (SG) that reached 45.9%, followed by Roux-en-Y gastric bypass (RYGB) (39.6%), and adjustable gastric banding (AGB) (7.4%). The annual percentage changes from 2013 revealed the increase of SG and decrease of RYGB in all the IFSO regions (USA/Canada, Europe, and Asia/Pacific) with the exception of Latin/South America, where SG decreased and RYGB represented the most frequent procedure. There was a further increase in the total number of bariatric/metabolic procedures in 2014 and SG is currently the most frequent surgical procedure in the world. This is the first survey that describes the endoluminal procedures, but the accuracy of provided data should be hopefully improved in the next future. We encourage the creation of further national registries and their continuous updates taking into account all new bariatric procedures including the endoscopic procedures that will obtain increasing importance in the near future.

  20. The general solution to HDR rendering

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    McCann, John

    2012-03-01

    Our High-Dynamic-Range (HDR) world is the result of nonuniform illumination. We like to believe that 21st century technology makes it possible to accurately reproduce any scene. On further study, we find that scene rendition remains a best compromise. Despite all the remarkable accomplishments in digital imaging, we cannot capture and reproduce the light in the world exactly. With still further study, we find that accurate reproduction is not necessary. We need an interdisciplinary study of image making - painting, photography and image processing - to find the general solution. HDR imaging would be very confusing, without two observations that resolve many paradoxes. First, optical veiling glare, that depends on the scene content, severely limits the range of light on cameras' sensors, and on retinas. Second, the neural spatial image processing in human vision counteracts glare with variable scene dependent responses. The counter actions of these optical and neural processes shape the goals of HDR imaging. Successful HDR increases the apparent contrast of details lost in the shadows and highlights of conventional images. They change the spatial relationships by altering the local contrast of edges and gradients. The goal of HDR imaging is displaying calculated appearance, rather than accurate light reproduction. By using this strategy we can develop universal algorithms that process all images, LDR and HDR, achromatic and color, by mimicking human vision. The study of the general solution for HDR imaging incorporates painting photography, vision research, color constancy and digital image processing.

  1. HDR Efex Pro After the Shoot

    CERN Document Server

    Sholik, Stan

    2011-01-01

    A concise, on-the-go guide to the new HDR Efex Pro imaging toolkit for photographers Now that you've gone mobile and HDR, you want to be able to download and enhance your favorite photos on the run, without having to return to the mother ship (i.e., your desktop computer). This book shows you just how to do that using the amazing HDR Efex Pro, the image editing toolset from Nik Software. In brilliant color and using plenty of show-stopping examples, this practical guide explains all tools and features. Follow numbered steps and you'll soon be handling things like alignment, ghosting control, h

  2. HDR ühest kaadrist? / Janno Loide

    Index Scriptorium Estoniae

    Loide, Janno

    2008-01-01

    HDR-töötluse (High dynamic range - pildi kõrge dünaamiline ulatus) ja toonide kohandamise (tone mapping) meetodite kasutamisest pildi digitaalsel salvestusel ning sobiva hele-tumeduse leidmisel loodusfotode parema kvaliteedi saamiseks

  3. Scientific progress on the Fenton Hill HDR project since 1983

    Energy Technology Data Exchange (ETDEWEB)

    Brown, D.W.; Duchane, D.V.

    1998-02-01

    The modern HDR concept originated at the Los Alamos National Laboratory and was first demonstrated at Fenton Hill, NM. Experience gained during the development of the deeper HDR reservoir at Fenton Hill clearly showed that HDR reservoirs are formed by opening pre-existing, but sealed, multiply connected joint sets. Subsequent flow testing indicated that sustained operation of HDR systems under steady state conditions is feasible. The most significant remaining HDR issues are related to economics and locational flexibility. Additional field test sites are needed to advance the understanding of HDR technology so that the vast potential of this resource can be economically realized around the world.

  4. Duodenal endoluminal barrier sleeve alters gut microbiota of ZDF rats.

    Science.gov (United States)

    Kim, T; Holleman, C L; Ptacek, T; Morrow, C D; Habegger, K M

    2017-03-01

    The combination of energy dense diets and reduced energy expenditure in modern society has escalated the prevalence of obesity and obesity-related comorbidities. Among these disease states, type-2 diabetics (T2D) are disproportionately associated with obesity, suggesting a shared etiology. In conjunction with defects in hormonal and inflammatory states, obesity and T2D are also characterized by dysbiosis. We have recently described the beneficial effects of duodenal nutrient exclusion, as induced by the duodenal endoluminal sleeve (DES); including body weight loss, prevented fat mass accumulation, and improved glucose tolerance in the ZDF rat, a rodent model of obesity and type-2 diabetes (T2D). To assess the relative role of DES on hindgut microbiota in the context of these metabolic changes, we analyzed cecal samples from rats implanted with a duodenal endoluminal sleeve (DES), or a sham control of this procedure. A group of pair-fed (pf) sham controls was also included to account for changes induced by reduced body weight and food intake. Analysis of hindgut microbiota following DES in the ZDF rat elucidated discrete changes in several microbial populations including a reduction in Paraprevotella family members of the Clostridiales order along with an increase in Akkermansia muciniphila and species of the Allobaculum and Bifidobacterium genera. Altogether, these observations suggest that like Roux-en Y gastric bypass (RYGB) and Metformin, regulation of gut microbiota may be a contributing factor to the therapeutic effects of DES.

  5. Endoluminal pharmacologic stimulation of the upper urinary tract.

    Science.gov (United States)

    Jakobsen, Jørn Skibsted

    2013-05-01

    The experiments performed in this PhD thesis were conducted at the Institute of Experimental Surgery, Skejby Hospital, Aarhus, Denmark and at the Laboratory of Animal Science, Odense University Hospital, Denmark. The thesis is based on 3 peer review articles published in international journals and a review. Diagnostic or therapeutic endoscopic upper urinary tract procedures are usually characterised as minimal invasive procedures and associated with a low complication rate. Most often fever or pain are seen and sometimes septicaemia. However, mucosa lesion or even ureteric ruptures are known complications. Research has suggested that high renal pelvic pressures generated during these procedures, might contribute to per-/postoperative complications seen, and even possible renal parenchymal damage. Nevertheless, local administration (endoluminal) of a relaxant drug has not previously been tried in order to lower renal pelvic pressure. The purposes of this thesis were to examine the effect of local administration (endoluminal) of the nonspecific β-adrenergic agonist ISOproterenol (ISO) on: 1) The normal pressure flow relation in porcine ureter, 2) The effect of endoluminal ISO perfusion during flexible ureterorenoscopy, 3) The pressure flow relation during semirigid ureterorenoscopy and 4) The cardiovascular system. Among other receptor-types β-adrenergic receptor are located in the upper urinary tract and the activation thereof mediates smooth muscle relaxation. We have shown - in an animal experimental model - that ISO added to the irrigation fluid had significant impact on the renal pelvic pressures generated during upper urinary tract endoscopy. ISO significantly and dose dependently reduced the normal pressure flow relations by approximately 80% without concomitant cardiovascular side effects or measurable plasma levels of ISO. During flexible ureterorenoscopy 0.1 µg/ml ISO added to the irrigation fluid significantly reduced renal pelvic pressure during

  6. Tratamiento del carcinoma de labio mediante braquiterapia de alta tasa de dosis

    OpenAIRE

    Finestres, Fernando; Guix Melcior, Benjamín; Cloquell Damian, Alberto; Chimenos Küstner, Eduardo; Tello Luque, José Ignacio

    2005-01-01

    Dado los diferentes métodos terapéuticos para el cáncer de labio, el objetivo del presente estudio es valorar los resultados obtenidos en un grupo prospectivo de 28 pacientes afectos de carcinoma de labio tratados mediante moldes externos de braquiterapia de alta tasa de dosis. Tanto por la remisión completa que ocurrió en todos los casos, la buena tolerancia a la terapia, la ausencia de complicaciones y de recurrencias, la facilidad de empleo de los moldes, la precisión ...

  7. Dosimetry revisited for the HDR {sup 192}Ir brachytherapy source model mHDR-v2

    Energy Technology Data Exchange (ETDEWEB)

    Granero, Domingo; Vijande, Javier; Ballester, Facundo; Rivard, Mark J. [Radiation Physics Department, ERESA, Hospital General Universitario, E-46014 Valencia (Spain); Department of Atomic, Molecular, and Nuclear Physics, University of Valencia, E-46100 Burjassot (Spain) and IFIC, CSIC-University of Valencia, E-46100 Burjassot (Spain); Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts 02111 (United States)

    2011-01-15

    Purpose: Recently, the manufacturer of the HDR {sup 192}Ir mHDR-v2 brachytherapy source reported small design changes (referred to herein as mHDR-v2r) that are within the manufacturing tolerances but may alter the existing dosimetric data for this source. This study aimed to (1) check whether these changes affect the existing dosimetric data published for this source; (2) obtain new dosimetric data in close proximity to the source, including the contributions from {sup 192}Ir electrons and considering the absence of electronic equilibrium; and (3) obtain scatter dose components for collapsed cone treatment planning system implementation. Methods: Three different Monte Carlo (MC) radiation transport codes were used: MCNP5, PENELOPE2008, and GEANT4. The source was centrally positioned in a 40 cm radius water phantom. Absorbed dose and collision kerma were obtained using 0.1 mm (0.5 mm) thick voxels to provide high-resolution dosimetry near (far from) the source. Dose-rate distributions obtained with the three MC codes were compared. Results: Simulations of mHDR-v2 and mHDR-v2r designs performed with three radiation transport codes showed agreement typically within 0.2% for r{>=}0.25 cm. Dosimetric contributions from source electrons were significant for r<0.25 cm. The dose-rate constant and radial dose function were similar to those from previous MC studies of the mHDR-v2 design. The 2D anisotropy function also coincided with that of the mHDR-v2 design for r{>=}0.25 cm. Detailed results of dose distributions and scatter components are presented for the modified source design. Conclusions: Comparison of these results to prior MC studies showed agreement typically within 0.5% for r{>=}0.25 cm. If dosimetric data for r<0.25 cm are not needed, dosimetric results from the prior MC studies will be adequate.

  8. Vivências de mulheres submetidas à braquiterapia: compreensão existencial

    Directory of Open Access Journals (Sweden)

    Maria Tereza Scramin Rosa

    2008-12-01

    Full Text Available Neste estudo, busquei compreender as vivências de mulheres portadoras de câncer uterino antes de submeterem ao tratamento braquiterápico. Trata-se de uma pesquisa qualitativa embasada na fenomenologia existencial de Martin Heidegger que possibilitou a apreensão dos momentos vividos por esses seres. Para participar dessa pesquisa, procurei por mulheres que haviam iniciado algum tipo de tratamento para câncer uterino. Selecionei aquelas que se submeteram à radioterapia em uma clínica de radioterapia situada no noroeste do Paraná, e, a posteriori, seriam submetidas à braquiterapia no período compreendido entre os meses de abril a maio de 2006. Foram entrevistadas quatro mulheres em um hospital especialista em oncologia no norte do Paraná, antes de iniciarem a braquiterapia. Para buscar os discursos dos sujeitos, utilizei a seguinte questão norteadora: “O que você sente antes de vivenciar a braquiterapia”? Da interpretação emergiram três temáticas: O ser-com-o-outro inautêntico no convívio do hospital; angústia ante o desconhecimento do tratamento; religiosidade: o caminho da esperança. Os resultados obtidos revelam a importância do cuidado holístico ao Ser que vivencia esta facticidade, pois, muitas vezes, a subjetividade do cuidado fica absorvida pela massificação das regras e normas institucionais.

  9. AVALIAÇÃO E CLASSIFICAÇÃO DA ESTENOSE VAGINAL PÓS-BRAQUITERAPIA

    Directory of Open Access Journals (Sweden)

    Luciana Martins da Rosa

    2016-01-01

    Full Text Available Revisión narrativa que identificó en los métodos de producción científicos utilizados para la evaluación y clasificación de las estenosis vaginal en mujeres después de braquiterapia vaginal . La recolección de datos se llevó a cabo en julio de 2013 en las publicaciones de la SciELO, Medline y PubMed , sin límite de tiempo, y estudios citados dos revisiones científicas que abordan el tema investigado aquí. El protocolo de búsqueda incluyó la descripción del método para la evaluación y clasificación de la estenosis vaginal. Análisis comparativo de los resultados mostró que existen diferencias entre los métodos utilizados por diferentes investigadores. Teniendo en cuenta este resultado, este estudio propone constituyentes para hacer un instrumento de evaluación para ser utilizado por las enfermeras. La estandarización de la técnica le ayudará en la detección precoz de la estenosis vaginal y atención a la mujer después de la braquiterapia vaginal.

  10. Aquarious Mountain Area, Arizona: APossible HDR Prospect

    Energy Technology Data Exchange (ETDEWEB)

    West, F.G.; Laughlin, A.W.

    1979-05-01

    Exploration for Hot Dry Rock (HDR) requires the ability to delineate areas of thermal enhancement. It is likely that some of these areas will exhibit various sorts of anomalous conditions such as seismic transmission delays, low seismic velocities, high attenuation of seismic waves, high electrical conductivity in the crust, and a relatively shallow depth to Curie point of Magnetization. The Aquarius Mountain area of northwest Arizona exhibits all of these anomalies. The area is also a regional Bouguer gravity low, which may indicate the presence of high silica type rocks that often have high rates of radioactive heat generation. The one deficiency of the area as a HDR prospect is the lack of a thermal insulating blanket.

  11. Color Calibration of HDR Image under a Known Illumination for Measuring Reflectance Property of Materials

    National Research Council Canada - National Science Library

    YOO, Hyunjin; KIM, Kang Y; LEE, Kwan H

    2009-01-01

    .... Hence, the HDR image can be used to measure the reflectance property of materials. In order to reproduce the original color of materials using this HDR image, characterization of HDR imaging is needed...

  12. A JPEG backward-compatible HDR image compression

    Science.gov (United States)

    Korshunov, Pavel; Ebrahimi, Touradj

    2012-10-01

    High Dynamic Range (HDR) imaging is expected to become one of the technologies that could shape next generation of consumer digital photography. Manufacturers are rolling out cameras and displays capable of capturing and rendering HDR images. The popularity and full public adoption of HDR content is however hindered by the lack of standards in evaluation of quality, file formats, and compression, as well as large legacy base of Low Dynamic Range (LDR) displays that are unable to render HDR. To facilitate wide spread of HDR usage, the backward compatibility of HDR technology with commonly used legacy image storage, rendering, and compression is necessary. Although many tone-mapping algorithms were developed for generating viewable LDR images from HDR content, there is no consensus on which algorithm to use and under which conditions. This paper, via a series of subjective evaluations, demonstrates the dependency of perceived quality of the tone-mapped LDR images on environmental parameters and image content. Based on the results of subjective tests, it proposes to extend JPEG file format, as the most popular image format, in a backward compatible manner to also deal with HDR pictures. To this end, the paper provides an architecture to achieve such backward compatibility with JPEG and demonstrates efficiency of a simple implementation of this framework when compared to the state of the art HDR image compression.

  13. Endoscopic gastric pouch plication – a novel endoluminal incision free approach to revisional bariatric surgery

    Directory of Open Access Journals (Sweden)

    Virk CS

    2010-04-01

    Full Text Available 10-40% of Roux-en-Y gastric bypass (RYGB patients regain significant weight after Roux-en-Y gastric bypass surgery due to dilation of the pouch and/or the gastrojejunal (GJ anastomosis. Traditional revision surgery is associated with significant morbidity (e.g. post-anastomotic GJ leak where less invasive endoluminal procedures may represent safer alternatives. The present article reports a case of the safe and successful use of endoluminal gastric pouch plication (EGPP using the StomaphyX™ device to correct both a dilated gastric pouch and a dilated gastrojejunostomy in a post-RYGB patient who regained significant weight.

  14. MO-B-BRC-04: MRI-Based Prostate HDR

    Energy Technology Data Exchange (ETDEWEB)

    Mourtada, F. [Christiana Care Hospital (United States)

    2016-06-15

    Brachytherapy has proven to be an effective treatment option for prostate cancer. Initially, prostate brachytherapy was delivered through permanently implanted low dose rate (LDR) radioactive sources; however, high dose rate (HDR) temporary brachytherapy for prostate cancer is gaining popularity. Needle insertion during prostate brachytherapy is most commonly performed under ultrasound (U/S) guidance; however, treatment planning may be performed utilizing several imaging modalities either in an intra- or post-operative setting. During intra-operative prostate HDR, the needles are imaged during implantation, and planning may be performed in real time. At present, the most common imaging modality utilized for intra-operative prostate HDR is U/S. Alternatively, in the post-operative setting, following needle implantation, patients may be simulated with computed tomography (CT) or magnetic resonance imaging (MRI). Each imaging modality and workflow provides its share of benefits and limitations. Prostate HDR has been adopted in a number of cancer centers across the nation. In this educational session, we will explore the role of U/S, CT, and MRI in HDR prostate brachytherapy. Example workflows and operational details will be shared, and we will discuss how to establish a prostate HDR program in a clinical setting. Learning Objectives: Review prostate HDR techniques based on the imaging modality Discuss the challenges and pitfalls introduced by the three imagebased options for prostate HDR brachytherapy Review the QA process and learn about the development of clinical workflows for these imaging options at different institutions.

  15. MO-B-BRC-03: CT-Based Prostate HDR

    Energy Technology Data Exchange (ETDEWEB)

    Zoberi, J. [Washington University School of Medicine (United States)

    2016-06-15

    Brachytherapy has proven to be an effective treatment option for prostate cancer. Initially, prostate brachytherapy was delivered through permanently implanted low dose rate (LDR) radioactive sources; however, high dose rate (HDR) temporary brachytherapy for prostate cancer is gaining popularity. Needle insertion during prostate brachytherapy is most commonly performed under ultrasound (U/S) guidance; however, treatment planning may be performed utilizing several imaging modalities either in an intra- or post-operative setting. During intra-operative prostate HDR, the needles are imaged during implantation, and planning may be performed in real time. At present, the most common imaging modality utilized for intra-operative prostate HDR is U/S. Alternatively, in the post-operative setting, following needle implantation, patients may be simulated with computed tomography (CT) or magnetic resonance imaging (MRI). Each imaging modality and workflow provides its share of benefits and limitations. Prostate HDR has been adopted in a number of cancer centers across the nation. In this educational session, we will explore the role of U/S, CT, and MRI in HDR prostate brachytherapy. Example workflows and operational details will be shared, and we will discuss how to establish a prostate HDR program in a clinical setting. Learning Objectives: Review prostate HDR techniques based on the imaging modality Discuss the challenges and pitfalls introduced by the three imagebased options for prostate HDR brachytherapy Review the QA process and learn about the development of clinical workflows for these imaging options at different institutions.

  16. MO-B-BRC-02: Ultrasound Based Prostate HDR

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Z. [Duke University Medical Center (United States)

    2016-06-15

    Brachytherapy has proven to be an effective treatment option for prostate cancer. Initially, prostate brachytherapy was delivered through permanently implanted low dose rate (LDR) radioactive sources; however, high dose rate (HDR) temporary brachytherapy for prostate cancer is gaining popularity. Needle insertion during prostate brachytherapy is most commonly performed under ultrasound (U/S) guidance; however, treatment planning may be performed utilizing several imaging modalities either in an intra- or post-operative setting. During intra-operative prostate HDR, the needles are imaged during implantation, and planning may be performed in real time. At present, the most common imaging modality utilized for intra-operative prostate HDR is U/S. Alternatively, in the post-operative setting, following needle implantation, patients may be simulated with computed tomography (CT) or magnetic resonance imaging (MRI). Each imaging modality and workflow provides its share of benefits and limitations. Prostate HDR has been adopted in a number of cancer centers across the nation. In this educational session, we will explore the role of U/S, CT, and MRI in HDR prostate brachytherapy. Example workflows and operational details will be shared, and we will discuss how to establish a prostate HDR program in a clinical setting. Learning Objectives: Review prostate HDR techniques based on the imaging modality Discuss the challenges and pitfalls introduced by the three imagebased options for prostate HDR brachytherapy Review the QA process and learn about the development of clinical workflows for these imaging options at different institutions.

  17. HDR Image Quality Enhancement Based on Spatially Variant Retinal Response

    Directory of Open Access Journals (Sweden)

    Horiuchi Takahiko

    2010-01-01

    Full Text Available There is a growing demand for being able to display high dynamic range (HDR images on low dynamic range (LDR devices. Tone mapping is a process for enhancing HDR image quality on an LDR device by converting the tonal values of the original image from HDR to LDR. This paper proposes a new tone mapping algorithm for enhancing image quality by deriving a spatially-variant operator for imitating S-potential response in human retina, which efficiently improves local contrasts while conserving good global appearance. The proposed tone mapping operator is studied from a system construction point of view. It is found that the operator is regarded as a natural extension of the Retinex algorithm by adding a global adaptation process to the local adaptation. The feasibility of the proposed algorithm is examined in detail on experiments using standard HDR images and real HDR scene images, comparing with conventional tone mapping algorithms.

  18. HDR color conversion with varying distortion metrics

    Science.gov (United States)

    Norkin, Andrey

    2016-09-01

    The paper compares three algorithms, which attenuate artifacts that may appear in HDR video in Y'CbCr 4:2:0 format. The algorithms attenuate artifacts in colors at the color gamut boundaries while also improving the objective quality. Two closed form solutions demonstrate the same subjective quality as the iterative approach, while being computationally simpler. One of the closed form solutions also shows similar objective results to the iterative algorithm. The choice of the upsampling filter in the pre-processing stage is important and may negatively affect both the objective and subjective quality if there is a mismatch with the upsampling filter used in the reconstruction.

  19. Anatomy of ureterovesical junction and distal ureter studied by endoluminal ultrasonography in vitro

    NARCIS (Netherlands)

    Roshani, H.; Dabhoiwala, N. F.; Verbeek, F. J.; Kurth, K. H.; Lamers, W. H.

    1999-01-01

    PURPOSE: The emerging technique of endoluminal ultrasonography (ELUS) provides a new modality for endoscopic visualization of the urinary tract which needs to be further evaluated. We studied the normal anatomy of distal ureter and ureterovesical junction using ELUS. MATERIALS AND METHODS: An

  20. The combined ipsilateral antegrade-retrograde approach to insert an endoluminal femoropopliteal bypass

    NARCIS (Netherlands)

    Lensvelt, M.M.A.; Zeebregts, C.J.A.; Stoer-Bouwman, M.; Reijnen, M.M.P.J.

    2011-01-01

    The endoluminal femoropopliteal bypass is a minimally invasive treatment modality for occlusive superficial femoral artery disease. Technical failure of endovascular treatment of chronic total occlusions is often caused by the inability to re-enter the true lumen. Re-entry devices have a high

  1. Single-layer HDR video coding with SDR backward compatibility

    Science.gov (United States)

    Lasserre, S.; François, E.; Le Léannec, F.; Touzé, D.

    2016-09-01

    The migration from High Definition (HD) TV to Ultra High Definition (UHD) is already underway. In addition to an increase of picture spatial resolution, UHD will bring more color and higher contrast by introducing Wide Color Gamut (WCG) and High Dynamic Range (HDR) video. As both Standard Dynamic Range (SDR) and HDR devices will coexist in the ecosystem, the transition from Standard Dynamic Range (SDR) to HDR will require distribution solutions supporting some level of backward compatibility. This paper presents a new HDR content distribution scheme, named SL-HDR1, using a single layer codec design and providing SDR compatibility. The solution is based on a pre-encoding HDR-to-SDR conversion, generating a backward compatible SDR video, with side dynamic metadata. The resulting SDR video is then compressed, distributed and decoded using standard-compliant decoders (e.g. HEVC Main 10 compliant). The decoded SDR video can be directly rendered on SDR displays without adaptation. Dynamic metadata of limited size are generated by the pre-processing and used to reconstruct the HDR signal from the decoded SDR video, using a post-processing that is the functional inverse of the pre-processing. Both HDR quality and artistic intent are preserved. Pre- and post-processing are applied independently per picture, do not involve any inter-pixel dependency, and are codec agnostic. Compression performance, and SDR quality are shown to be solidly improved compared to the non-backward and backward-compatible approaches, respectively using the Perceptual Quantization (PQ) and Hybrid Log Gamma (HLG) Opto-Electronic Transfer Functions (OETF).

  2. A review of nonstandardized applicators digitization in Nucletron™ HDR procedures.

    Science.gov (United States)

    Wang, Kelin; Ferenci, Michele S; de la Zerda, Alberto; Padgett, Kyle R; Bossart, Elizabeth L; Chao, Ming; Shao, Hua; Zhang, Mutain

    2017-09-01

    The major errors in HDR procedures were failures to enter the correct treatment distance, which could be caused by either entering wrong transmission lengths or imprecisely digitizing the dwelling positions. Most of those errors were not easily avoidable by enhancing the HDR management level because they were caused by implementations of nonstandardized applicators utilizing transmission tubes of different lengths in standard HDR procedures. We performed this comprehensive study to include all possible situations with different nonstandardized applicators that frequently occurred in HDR procedures, provide corresponding situations with standard applicator as comparisons, list all possible errors and in planning, clarify the confusions in offsets setting, and provide mathematical and quantitative solutions for each given scenarios. Training on HDR procedures with nonstandardized applicators are normally not included in most residential program for medical physics, thus this study could be meaningful in both clinical and educational purpose. At precision of 1 mm, our study could be used as the essential and practical reference for finding the correct treatment length as well as locating the accurate dwelling positions in any HDR procedure with nonstandardized applicators. © 2017 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

  3. Development of an endoluminal intestinal attachment for a clinically applicable distraction enterogenesis device.

    Science.gov (United States)

    Demehri, Farokh R; Utter, Brent; Freeman, Jennifer J; Fukatsu, Yumi; Luntz, Jonathan; Brei, Diann; Teitelbaum, Daniel H

    2016-01-01

    Previous methods of distraction enterogenesis have relied upon blind-ending intestinal segments or transmural device fixation, requiring multiple operations and potential bowel injury. We hypothesized that using a novel attachment would allow reversible device coupling to the luminal bowel surface, achieving effective endoluminal distraction. A telescopic hydraulic device was designed with latex balloon attachments covered with high-friction mesh and a dilating fenestrated elastic mask (DFM attachment), allowing mesh-to-mucosa contact only with inflation. Yorkshire pigs underwent jejunal Roux-en-Y limb creation and device placement via jejunostomy. Devices underwent 3 cycles of balloon inflation and hydraulic extension/retraction per day for 7 days and then explanted and studied for efficacy. DFM attachment allowed reversible, high-strength endoluminal coupling without tissue injury or reduction in bowel perfusion. After 7 day implant, distracted bowel achieved a 44 ± 2% increase in length vs. fed, nondistracted bowel, corresponding to a gain of 7.1 ± 0.3 cm. Distracted bowel demonstrated increased epithelial cell proliferation vs. control bowel. Attachment sites demonstrated villus flattening, increased crypt depth, thicker muscularis mucosa, and unchanged muscularis propria thickness vs. Novel high-strength, reversible attachments enabled fully endoluminal distraction enterogenesis, achieving length gains comparable to open surgical techniques. This approach may allow development of clinically applicable technology for SBS treatment. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Thermal therapy of pancreatic tumours using endoluminal ultrasound: Parametric and patient-specific modelling.

    Science.gov (United States)

    Adams, Matthew S; Scott, Serena J; Salgaonkar, Vasant A; Sommer, Graham; Diederich, Chris J

    2016-01-01

    The aim of this study is to investigate endoluminal ultrasound applicator configurations for volumetric thermal ablation and hyperthermia of pancreatic tumours using 3D acoustic and biothermal finite element models. Parametric studies compared endoluminal heating performance for varying applicator transducer configurations (planar, curvilinear-focused, or radial-diverging), frequencies (1-5 MHz), and anatomical conditions. Patient-specific pancreatic head and body tumour models were used to evaluate feasibility of generating hyperthermia and thermal ablation using an applicator positioned in the duodenal or stomach lumen. Temperature and thermal dose were calculated to define ablation (> 240 EM(43 °C)) and moderate hyperthermia (40-45 °C) boundaries, and to assess sparing of sensitive tissues. Proportional-integral control was incorporated to regulate maximum temperature to 70-80 °C for ablation and 45 °C for hyperthermia in target regions. Parametric studies indicated that 1-3 MHz planar transducers are the most suitable for volumetric ablation, producing 5-8 cm(3) lesion volumes for a stationary 5-min sonication. Curvilinear-focused geometries produce more localised ablation to 20-45 mm depth from the GI tract and enhance thermal sparing (T(max) Modelling studies indicate the feasibility of endoluminal ultrasound for volumetric thermal ablation or hyperthermia treatment of pancreatic tumour tissue.

  5. Thermal therapy of pancreatic tumors using endoluminal ultrasound: parametric and patient-specific modeling

    Science.gov (United States)

    Adams, Matthew S.; Scott, Serena J.; Salgaonkar, Vasant A.; Sommer, Graham; Diederich, Chris J.

    2016-01-01

    Purpose To investigate endoluminal ultrasound applicator configurations for volumetric thermal ablation and hyperthermia of pancreatic tumors using 3D acoustic and biothermal finite element models. Materials and Methods Parametric studies compared endoluminal heating performance for varying applicator transducer configurations (planar, curvilinear-focused, or radial-diverging), frequencies (1–5 MHz), and anatomical conditions. Patient-specific pancreatic head and body tumor models were used to evaluate feasibility of generating hyperthermia and thermal ablation using an applicator positioned in the duodenal or stomach lumen. Temperature and thermal dose were calculated to define ablation (>240 EM43°C) and moderate hyperthermia (40–45 °C) boundaries, and to assess sparing of sensitive tissues. Proportional-integral control was incorporated to regulate maximum temperature to 70–80 °C for ablation and 45 °C for hyperthermia in target regions. Results Parametric studies indicated that 1–3 MHz planar transducers are most suitable for volumetric ablation, producing 5–8 cm3 lesion volumes for a stationary 5 minute sonication. Curvilinear-focused geometries produce more localized ablation to 20–45 mm depth from the GI tract and enhance thermal sparing (TmaxModeling studies indicate the feasibility of endoluminal ultrasound for volumetric thermal ablation or hyperthermia treatment of pancreatic tumor tissue. PMID:27097663

  6. Ultrasonography for endoleak detection after endoluminal abdominal aortic aneurysm repair.

    Science.gov (United States)

    Abraha, Iosief; Luchetta, Maria Laura; De Florio, Rita; Cozzolino, Francesco; Casazza, Giovanni; Duca, Piergiorgio; Parente, Basso; Orso, Massimiliano; Germani, Antonella; Eusebi, Paolo; Montedori, Alessandro

    2017-06-09

    People with abdominal aortic aneurysm who receive endovascular aneurysm repair (EVAR) need lifetime surveillance to detect potential endoleaks. Endoleak is defined as persistent blood flow within the aneurysm sac following EVAR. Computed tomography (CT) angiography is considered the reference standard for endoleak surveillance. Colour duplex ultrasound (CDUS) and contrast-enhanced CDUS (CE-CDUS) are less invasive but considered less accurate than CT. To determine the diagnostic accuracy of colour duplex ultrasound (CDUS) and contrast-enhanced-colour duplex ultrasound (CE-CDUS) in terms of sensitivity and specificity for endoleak detection after endoluminal abdominal aortic aneurysm repair (EVAR). We searched MEDLINE, Embase, LILACS, ISI Conference Proceedings, Zetoc, and trial registries in June 2016 without language restrictions and without use of filters to maximize sensitivity. Any cross-sectional diagnostic study evaluating participants who received EVAR by both ultrasound (with or without contrast) and CT scan assessed at regular intervals. Two pairs of review authors independently extracted data and assessed quality of included studies using the QUADAS 1 tool. A third review author resolved discrepancies. The unit of analysis was number of participants for the primary analysis and number of scans performed for the secondary analysis. We carried out a meta-analysis to estimate sensitivity and specificity of CDUS or CE-CDUS using a bivariate model. We analysed each index test separately. As potential sources of heterogeneity, we explored year of publication, characteristics of included participants (age and gender), direction of the study (retrospective, prospective), country of origin, number of CDUS operators, and ultrasound manufacturer. We identified 42 primary studies with 4220 participants. Twenty studies provided accuracy data based on the number of individual participants (seven of which provided data with and without the use of contrast). Sixteen of

  7. Proposed methodology for estimating the in HDR brachytherapy facilities Ir-192; Propuesta de metodologia para estimar la dosis absorbida en la entrada del laberinto en instalaciones de braquiterapia HDR con Ir-192

    Energy Technology Data Exchange (ETDEWEB)

    Pujades-Clamarchirant, M. C.; Perez-Calatayud, J.; Ballester, F.; Gimeno, J.; Granero, D.; Camacho, C.; Lliso, F.; Carmona, V.; Vijande, J.

    2011-07-01

    In the absence of procedures for assessing the design of a room brachytherapy (BT) with maze, usually adopting the formalism of external irradiation with different variations, The purpose of this study is to adapt the methodology of NCRP151 [1] to estimate the absorbed dose at the entrance to a room of ET and compare with the corresponding dosimetry data obtained with Monte Carlo (MC) in a previous work.

  8. In vivo dosimetry HDR brachytherapy prostate with source CO-60: Results of measures in a point urethra; Dosimetria in vivo en braquiterapia HDR de prostate con fuente de CO-60: Resultados de medidas en un punto de uretra

    Energy Technology Data Exchange (ETDEWEB)

    Latorre, D.; Fernandez, J.; Rivero, G.; Crelgo, D.; Gonzalez, J. M.; Sanchez, P.; Villace, A.; Sanchez, E.; Arroyo, M. A.; Garcia, E.; Trabanco, E.

    2015-07-01

    In this study we present and analyze the results of the in vivo dosimetry made a point of urethra with a group of 30 patients treated with brachytherapy prostate high rate with Co-60 source. Taking into account the uncertainties, the results and integration, globally evaluate this system DIV. This DIV system, due to its ease of calibration and use, and provides a relatively simple integration way to avoid serious errors in administering treatment. (Author)

  9. HDR video synthesis for vision systems in dynamic scenes

    Science.gov (United States)

    Shopovska, Ivana; Jovanov, Ljubomir; Goossens, Bart; Philips, Wilfried

    2016-09-01

    High dynamic range (HDR) image generation from a number of differently exposed low dynamic range (LDR) images has been extensively explored in the past few decades, and as a result of these efforts a large number of HDR synthesis methods have been proposed. Since HDR images are synthesized by combining well-exposed regions of the input images, one of the main challenges is dealing with camera or object motion. In this paper we propose a method for the synthesis of HDR video from a single camera using multiple, differently exposed video frames, with circularly alternating exposure times. One of the potential applications of the system is in driver assistance systems and autonomous vehicles, involving significant camera and object movement, non- uniform and temporally varying illumination, and the requirement of real-time performance. To achieve these goals simultaneously, we propose a HDR synthesis approach based on weighted averaging of aligned radiance maps. The computational complexity of high-quality optical flow methods for motion compensation is still pro- hibitively high for real-time applications. Instead, we rely on more efficient global projective transformations to solve camera movement, while moving objects are detected by thresholding the differences between the trans- formed and brightness adapted images in the set. To attain temporal consistency of the camera motion in the consecutive HDR frames, the parameters of the perspective transformation are stabilized over time by means of computationally efficient temporal filtering. We evaluated our results on several reference HDR videos, on synthetic scenes, and using 14-bit raw images taken with a standard camera.

  10. O custo da cura: vivências de conforto e desconforto de mulheres submetidas à braquiterapia

    Directory of Open Access Journals (Sweden)

    Míbsam Lysia Carvalho Alves Soares

    2016-06-01

    Full Text Available RESUMO Objetivo: Descrever as vivências de conforto e desconforto de mulheres que se submeteram à braquiterapia para tratamento de câncer do colo uterino. Métodos: Estudo qualitativo, desenvolvido em 2013, embasado na Teoria do Conforto de Kolcaba e realizado por meio de entrevistas semiestruturadas com oito mulheres que concluíram o tratamento há, no mínimo, seis meses. Resultados: Sobressaíram os seguintes desconfortos: dor do procedimento e dos efeitos pós-tratamento, no contexto físico; medo do desconhecido e do sofrimento, falta de acompanhante, estresse por sentir-se constrangida durante o tratamento, baixa autoestima e trauma psicológico pós-terapia, no contexto psicoespiritual. As medidas de conforto consistiram no diálogo com o profissional, administração de medicações e uso da fé e espiritualidade. Conclusão: Os resultados oferecem subsídios para a prática de profissionais de saúde em relação aos confortos e desconfortos que merecem ser alvo de intervenções na assistência à mulher com câncer.

  11. 1-Year Results of a Multicenter Randomized Controlled Trial Comparing Heparin-Bonded Endoluminal to Femoropopliteal Bypass.

    Science.gov (United States)

    Reijnen, Michel M P J; van Walraven, Laurens A; Fritschy, Wilbert M; Lensvelt, Mare M A; Zeebregts, Clark J; Lemson, M Suzanna; Wikkeling, Otmar R M; Smeets, Luuk; Holewijn, Suzanne

    2017-11-27

    This study sought to compare heparin-bonded endografts with femoropopliteal bypass, including quality of life, using general health and disease-specific questionnaires as well as patency rates. Endovascular treatment continues to advance and is gaining acceptance as primary treatment for long occlusive or stenotic lesions in the superficial femoral artery. Heparin-bonded expanded polytetrafluoroethylene endografts have been related to outcomes comparable to bypass surgery, but this has not been tested in a randomized fashion. A multicenter randomized-controlled trial was performed comparing femoropopliteal bypass with heparin-bonded expanded polytetrafluoroethylene endografts. Data were analyzed on an intention-to-treat and per-protocol manner. A total of 129 patients were randomized and 125 patients were treated, 63 in the endoluminal and 62 in the surgical group (42 venous, 20 prosthetic). Enrollment was terminated before reaching the predefined target number for patency. Baseline characteristics and anatomical data were similar. Patients were treated for critical limb ischemia in 38.1% and 32.2% in the endoluminal and surgical arms, respectively. Mean lesion length was 23 cm in both groups and lesions were largely TransAtlantic Inter-Society Consensus II D. Hospitalization time and 30-day morbidity were significantly lower in the endoluminal group, without differences in serious adverse events (n = 5 each; surgical: 4 venous and 1 polytetrafluoroethylene bypass). There were no significant differences in Rutherford category between groups at any time point. At 30 days the endoluminal group showed a greater improvement in quality-of-life scores. At 1 year, these differences had largely disappeared and no differences in primary (endoluminal: 64.8%; surgical: 63.6%), assisted primary (endoluminal: 78.1%; surgical: 79.8%), secondary patency (endoluminal: 85.9%; surgical: 83.3%), and target vessel revascularization (endoluminal: 72.1%; surgical: 71.0%) were observed

  12. Endoluminal dilatation for embedded hemodialysis catheters: A case-control study of factors associated with embedding and clinical outcomes.

    Directory of Open Access Journals (Sweden)

    Hari Talreja

    Full Text Available With the increasing frequency of tunneled hemodialysis catheter use there is a parallel increase in the need for removal and/or exchange. A small but significant minority of catheters become embedded or 'stuck' and cannot be removed by traditional means. Management of embedded catheters involves cutting the catheter, burying the retained fragment with a subsequent increased risk of infections and thrombosis. Endoluminal dilatation may provide a potential safe and effective technique for removing embedded catheters, however, to date, there is a paucity of data.1 To determine factors associated with catheters becoming embedded and 2 to determine outcomes associated with endoluminal dilatation.All patients with endoluminal dilatation for embedded catheters at our institution since Jan. 2010 were included. Patients who had an embedded catheter were matched 1:3 with patients with uncomplicated catheter removal. Baseline patient and catheter characteristics were compared. Outcomes included procedural success and procedure-related infection. Logistic regression models were used to determine factors associated with embedded catheters.We matched 15 cases of embedded tunneled catheters with 45 controls. Among patients with embedded catheters, there were no complications with endoluminal dilatation. Factors independently associated with embedded catheters included catheter dwell time (> 2 years and history of central venous stenosis.Embedded catheters can be successfully managed by endoluminal dilatation with minimal complications and factors associated with embedding include dwell times > 2 years and/or with a history of central venous stenosis.

  13. FVP10: enhancements of VPX for SDR/HDR applications

    Science.gov (United States)

    Topiwala, Pankaj; Dai, Wei; Krishnan, Madhu

    2016-09-01

    This paper describes a study to investigate possible ways to improve the VPX codecs in the context of both 8-bit SDR video and 10-bit HDR video content, for two types of applications: streaming and high quality (near lossless) coding for content contribution editing. For SDR content, the following tools are investigated: (a) lapped biorthogonal transforms for near lossless applications; and (b) optimized resampling filter pairs for adaptive resolution coding in streaming applications. For HDR content, a data adaptive grading technique in conjunction with the VP9/VP10 encoder is studied. Both the objective metrics (measured using BD rate) and informal subjective visual quality assessments are recorded. It is asserted that useful improvements are possible in each of these categories. In particular, substantial value is offered in the coding of HDR content, and especially in creating a coding scheme offering backwards compatibility with SDR.

  14. Innovative Design of a Laparoscopic Probe for Non-Invasive Intraoperative Detection of Small Endoluminal Digestive Tumours

    Directory of Open Access Journals (Sweden)

    Bogdan Mocan

    2015-12-01

    Full Text Available The present paper highlights the design methodology, the prototype development and the ex-vivo testing of a sensing laparoscopic probe that could be used by surgeons and by surgeon’s assistive robotic systems for detection of small endoluminal digestive tumours. The proposed design framework guides the decision-makers towards a superior balance between quality, efficiency and surgical procedure issues in medical instruments development. A prototype of the sensitive laparoscopic probe for non-invasive intraoperative detection of small endoluminal digestive tumours was developed. The prototype was tested in ex-vivo experimental conditions – open and laparoscopic surgery. The results reveals that the developed prototype is easy to use, adequate and efficient in precise detection of small endoluminal digestive tumours in-between 60÷85% of cases.

  15. Evaluating HDR photos using Web 2.0 technology

    Science.gov (United States)

    Qiu, Guoping; Mei, Yujie; Duan, Jiang

    2011-01-01

    High dynamic range (HDR) photography is an emerging technology that has the potential to dramatically enhance the visual quality and realism of digital photos. One of the key technical challenges of HDR photography is displaying HDR photos on conventional devices through tone mapping or dynamic range compression. Although many different tone mapping techniques have been developed in recent years, evaluating tone mapping operators prove to be extremely difficult. Web2.0, social media and crowd-sourcing are emerging Internet technologies which can be harnessed to harvest the brain power of the mass to solve difficult problems in science, engineering and businesses. Paired comparison is used in the scientific study of preferences and attitudes and has been shown to be capable of obtaining an interval-scale ordering of items along a psychometric dimension such as preference or importance. In this paper, we exploit these technologies for evaluating HDR tone mapping algorithms. We have developed a Web2.0 style system that enables Internet users from anywhere to evaluate tone mapped HDR photos at any time. We adopt a simple paired comparison protocol, Internet users are presented a pair of tone mapped images and are simply asked to select the one that they think is better or click a "no difference" button. These user inputs are collected in the web server and analyzed by a rank aggregation algorithm which ranks the tone mapped photos according to the votes they received. We present experimental results which demonstrate that the emerging Internet technologies can be exploited as a new paradigm for evaluating HDR tone mapping algorithms. The advantages of this approach include the potential of collecting large user inputs under a variety of viewing environments rather than limited user participation under controlled laboratory environments thus enabling more robust and reliable quality assessment. We also present data analysis to correlate user generated qualitative

  16. Deep ensemble learning of virtual endoluminal views for polyp detection in CT colonography

    Science.gov (United States)

    Umehara, Kensuke; Näppi, Janne J.; Hironaka, Toru; Regge, Daniele; Ishida, Takayuki; Yoshida, Hiroyuki

    2017-03-01

    Robust training of a deep convolutional neural network (DCNN) requires a very large number of annotated datasets that are currently not available in CT colonography (CTC). We previously demonstrated that deep transfer learning provides an effective approach for robust application of a DCNN in CTC. However, at high detection accuracy, the differentiation of small polyps from non-polyps was still challenging. In this study, we developed and evaluated a deep ensemble learning (DEL) scheme for reviewing of virtual endoluminal images to improve the performance of computer-aided detection (CADe) of polyps in CTC. Nine different types of image renderings were generated from virtual endoluminal images of polyp candidates detected by a conventional CADe system. Eleven DCNNs that represented three types of publically available pre-trained DCNN models were re-trained by transfer learning to identify polyps from the virtual endoluminal images. A DEL scheme that determines the final detected polyps by a review of the nine types of VE images was developed by combining the DCNNs using a random forest classifier as a meta-classifier. For evaluation, we sampled 154 CTC cases from a large CTC screening trial and divided the cases randomly into a training dataset and a test dataset. At 3.9 falsepositive (FP) detections per patient on average, the detection sensitivities of the conventional CADe system, the highestperforming single DCNN, and the DEL scheme were 81.3%, 90.7%, and 93.5%, respectively, for polyps ≥6 mm in size. For small polyps, the DEL scheme reduced the number of false positives by up to 83% over that of using a single DCNN alone. These preliminary results indicate that the DEL scheme provides an effective approach for improving the polyp detection performance of CADe in CTC, especially for small polyps.

  17. Avaliação dosimétrica de uma combinação de aplicadores para braquiterapia de tumores do colo uterino com acometimento da porção distal da vagina

    OpenAIRE

    Guimarães,Roger Guilherme Rodrigues; Carvalho,Heloisa de Andrade; Stuart,Silvia Radwanski; Rubo,Rodrigo Augusto; Seraide,Rodrigo Migotto

    2009-01-01

    OBJETIVO: Avaliar uma alternativa de braquiterapia para tumores do colo uterino acometendo a porção distal da vagina, sem aumentar os riscos de toxicidade. MATERIAIS E MÉTODOS: Estudo teórico comparando três diferentes aplicadores de braquiterapia intracavitária de alta taxa de dose: sonda intrauterina e cilindro vaginal (SC); sonda e anel associado ao cilindro vaginal (SA+C) e um aplicador virtual com sonda, anel e cilindro vaginal em um único conjunto (SAC). Foram prescritas doses de 7 Gy n...

  18. Calculation of the Transit Dose in HDR Brachytherapy Based on ...

    African Journals Online (AJOL)

    The Monte Carlo method, which is the gold standard for accurate dose calculations in radiotherapy, was used to obtain the transit doses around a high dose rate (HDR) brachytherapy implant with thirteen dwell points. The midpoints of each of the inter-dwell separations, of step size 0.25 cm, were representative of the ...

  19. High dynamic range (HDR) virtual bronchoscopy rendering for video tracking

    Science.gov (United States)

    Popa, Teo; Choi, Jae

    2007-03-01

    In this paper, we present the design and implementation of a new rendering method based on high dynamic range (HDR) lighting and exposure control. This rendering method is applied to create video images for a 3D virtual bronchoscopy system. One of the main optical parameters of a bronchoscope's camera is the sensor exposure. The exposure adjustment is needed since the dynamic range of most digital video cameras is narrower than the high dynamic range of real scenes. The dynamic range of a camera is defined as the ratio of the brightest point of an image to the darkest point of the same image where details are present. In a video camera exposure is controlled by shutter speed and the lens aperture. To create the virtual bronchoscopic images, we first rendered a raw image in absolute units (luminance); then, we simulated exposure by mapping the computed values to the values appropriate for video-acquired images using a tone mapping operator. We generated several images with HDR and others with low dynamic range (LDR), and then compared their quality by applying them to a 2D/3D video-based tracking system. We conclude that images with HDR are closer to real bronchoscopy images than those with LDR, and thus, that HDR lighting can improve the accuracy of image-based tracking.

  20. Coexistence Mechanism for Colocated HDR/LDR WPANs Air Interfaces

    Directory of Open Access Journals (Sweden)

    Prasad Ramjee

    2010-01-01

    Full Text Available This paper addresses the issues of interference management among Low Data Rate (LDR and High Data Rate (HDR WPAN air interfaces that are located in close-proximity (up to 10 cm and eventually on the same multimode device. After showing the noticeable performance degradation in terms of Bit Error Rate (BER and goodput due to the out-of-band interference of an HDR air interface over an LDR air interface, the paper presents a novel coexistence mechanism, named Alternating Wireless Activity (AWA, which is shown to greatly improve the performance in terms of goodput of the most interference vulnerable air interface (i.e., the LDR air interface. The main difference of the proposed mechanism with respect to other collaborative mechanisms based on time-scheduling is that it synchronizes the transmission of the LDR and HDR WPANs at the superframe level instead of packet level. Advantages and limitations of this choice are presented in the paper. Furthermore the functionalities of the AWA mechanism are positioned in a common protocol layer over the Medium Access Control (MAC sublayers of the HDR and LDR devices and it can be used with any standard whose MAC is based on a superframe structure.

  1. Is Endoluminal Bariatric Therapy a New Paradigm of Treatment for Obesity?

    Science.gov (United States)

    Fanelli, Robert D; Andrew, Brandon D

    2016-04-01

    The prevalence of obesity has steadily increased throughout recent decades, and along with it, the costs of caring for the associated comorbid conditions has increased as well. Traditional bariatric surgical procedures generally are safe and effective, but patient acceptance, the risk of minor and sometimes serious complications, costs, and insurance coverage have limited the application of these techniques to the treatment of a minority of patients. Endoluminal techniques represent newer approaches to weight loss that can be used independently or in concert with traditional medical and surgical treatments for obesity, with varying degrees of success. It is anticipated that less invasiveness will increase the appeal across a broader representation of patients, perhaps increasing the number of obese patients who choose an intervention over medical management and possibly resulting in a greater total loss of excess body weight across a population; this may reduce costs involved in treating the complications of weight-related comorbidities. Acceptance of endoluminal bariatric procedures and devices will hinge on proving safety, efficacy, and value. Copyright © 2016 AGA Institute. Published by Elsevier Inc. All rights reserved.

  2. The Perth HLB bifurcated endoluminal graft: a review of the experience and intermediate results.

    Science.gov (United States)

    Lawrence-Brown, M; Sieunarine, K; Hartley, D; van Schie, G; Goodman, M A; Prendergast, F J

    1998-06-01

    Endoluminal grafting for abdominal aortic aneurysm based upon Dacron-coated Z stents was commenced in March 1993. A modular system for treatment of infrarenal aorto-iliac aneurysmal disease was developed in 1994. The experimental model, method of delivery, graft construction and initial results were reported. Since 1994, 108 bifurcated HLB (Perth) endografts for infrarenal aorto-iliac aneurysmal disease have been implemented. Initial technical success in deployment and exclusion of the aneurysm was achieved in 94 (87%) cases. Secondary endovascular procedures were performed in six cases and were successful in excluding the aneurysm. Ninety patients are alive currently. Twelve have died of co-morbid conditions. Six have died of aneurysmal disease, either from rupture or the result of treatment attempts. Fifteen early endoleaks (within 30 days) have been detected with three persisting. Four have sealed without further intervention, six after the secondary procedure and two patients have died. Conversion to open aneurysmal repair has been performed in five cases: three early and two late. Two of the early group but none of the late intervention group died. No graft infections have been detected to date. With increasing experience criteria for patient selection for endoluminal grafting and the type of graft to be inserted, have been developed. These criteria, lessons learnt and technical points of importance are discussed.

  3. Malformaciones venosas orofaciales de bajo flujo: esclerosis endoluminal con láser de diodo Low-flow orofacial venous malformations: endoluminal sclerosis with a diode laser

    Directory of Open Access Journals (Sweden)

    M. Puche Torres

    2010-06-01

    Full Text Available Introducción: Las anomalías vasculares son procesos frecuentes que se localizan en más del 50% de los casos en la región de la cabeza y el cuello. Las técnicas clásicas de tratamiento, tales como la cirugía y la esclerosis química, han dado paso a modernas técnicas menos invasivas, tales como el láser Nd:YAG. Por otra parte, se ha utilizado con éxito el láser de diodo (980 nm para el tratamiento de varices mediante esclerosis endoluminal. Nuestra propuesta es la utilización del láser de diodo (l 980 nm para provocar una esclerosis por fotocoagulación intralesional de las malformaciones venosas de bajo flujo dada la capacidad de este láser de ser transmitido por fibra óptica. Objetivo: Exponer nuestros resultados en el tratamiento de malformaciones venosas de bajo flujo (MVBF orofaciales mediante la terapéutica de esclerosis endoluminal con láser de diodo. Material y métodos: Revisamos 84 pacientes que presentaban MVBF orofaciales tratados con láser de diodo. Describimos la técnica de realización y se muestran los resultados postoperatorios a corto plazo. Resultados: Tras un periodo de seguimiento no inferior a 12 meses se constató curación en el 95,24% aplicando una o dos sesiones y solamente en 4 casos se objetivó recidiva. Concluimos que la técnica de esclerosis endoluminal con láser de diodo de MVBF en el área orofacial se constituye como una nueva técnica de tratamiento, mínimamente invasiva, ambulatoria, y que permite la resolución de los casos sin tener que recurrir a cirugías más agresivas y con excelentes resultados funcionales y estéticos.Background: Vascular anomalies are common processes that involve the head and neck region in more than 50% of the cases. Traditional treatment options such as surgery and chemical sclerosis have given way to modern less-invasive techniques, including Nd:YAG laser treatment. On the other hand, 980 nm laser diode has been successfully used for the endovenous sclerosis

  4. Hydrophilic surface modification of polymer vascular prostheses and metal endoluminal stents

    Science.gov (United States)

    Amery, Drew Powell

    1997-12-01

    Large diameter vascular replacements of GORE-TEXsp°ler or Dacronsp°ler are frequently used to replace damaged arteries. Poor long term patency of small diameter grafts, 6 millimeters or less, is attributed to platelet adhesion and the inability to regenerate a blood contacting surface of vascular endothelium. Metal endoluminal stents are vascular prostheses used to keep arterial lumens open following angioplasty. Complications for these implants include short term thrombogenicity and long term restenosis. This study was directed to the synthesis and characterization of more biocompatible surfaces for these devices. Gamma radiation induced-graft polymerization and radio frequency plasma activation was investigated to surface modify polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), expanded polytetrafluoroethylene (ePTFE), and 316 stainless steel. To mimic natural biocompatible tissue surfacesl a series of hydrophilic polymers were grafted onto PMMA, PET, and ePTFE. Hydrophilic graft polymers were derived from N-vinyl pyrrolidone (NVP), potassium sulfopropylacrylate (KSPA), and dimethylacrylamide, and were grafted copolymerized with several bioactive compounds in a two step modification process. Complex graft surfaces containing fibronectin (Fn), laminin (Lm), type IV collagen (IV), heparin sulfate (Hp), albumin (Alb), and a synthetic fibronectin like protein polymer (RGD) were prepared. For surface modification of endoluminal stents of 316 stainless and tantalum, a combination of RF plasma activation combined with gamma radiation induced grafting was studied. Plasma deposition of hydrophobic poly(hexane) primer layers with water plasma oxidation were examined for initial metal surface activation. Surfaces were characterized by gravimetric analysis, contact angle goniometry, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), Auger depth proGling, optical microscopy (OM), and low voltage scanning electron

  5. SUrgical versus PERcutaneous Bypass : SUPERB-trial; Heparin-bonded endoluminal versus surgical femoro-popliteal bypass: study protocol for a randomized controlled trial

    NARCIS (Netherlands)

    Lensvelt, Mare M. A.; Holewijn, Suzanne; Fritschy, Wilbert M.; Wikkeling, Otmar R. M.; van Walraven, Laurens A.; de Vries, Bas M. Wallis; Zeebregts, Clark J.; Reijnen, Michel M. P. J.

    2011-01-01

    Background: Endovascular treatment options for the superficial femoral artery are evolving rapidly. For long lesions, the venous femoropopliteal bypass considered to be superior above the prosthetic bypass. An endoluminal bypass, however, may provide equal patency rates compared to the prosthetic

  6. SUrgical versus PERcutaneous Bypass: SUPERB-trial; Heparin-bonded endoluminal versus surgical femoro-popliteal bypass: study protocol for a randomized controlled trial

    NARCIS (Netherlands)

    Lensvelt, M.M.A.; Holewijn, S.; Fritschy, W.M.; Wikkeling, O.R.; Walraven, L.A. van; Wallis de Vries, B.M.; Zeebregts, C.J.A.; Reijnen, M.M.P.J.

    2011-01-01

    BACKGROUND: Endovascular treatment options for the superficial femoral artery are evolving rapidly. For long lesions, the venous femoropopliteal bypass considered to be superior above the prosthetic bypass. An endoluminal bypass, however, may provide equal patency rates compared to the prosthetic

  7. The use of nomograms in LDR-HDR prostate brachytherapy

    Directory of Open Access Journals (Sweden)

    Ma Carmen Pujades

    2011-09-01

    Full Text Available Purpose: The common use of nomograms in Low Dose Rate (LDR permanent prostate brachytherapy (BT allowsto estimate the number of seeds required for an implant. Independent dosimetry verification is recommended for eachclinical dosimetry in BT. Also, nomograms can be useful for dose calculation quality assurance and they could be adaptedto High Dose Rate (HDR. This work sets nomograms for LDR and HDR prostate-BT implants, which are applied tothree different institutions that use different implant techniques. Material and methods: Patients treated throughout 2010 till April 2011 were considered for this study. This examplewas chosen to be the representative of the latest implant techniques and to ensure consistency in the planning. A sufficientnumber of cases for both BT modalities, prescription dose and different work methodology (depending on theinstitution were taken into account. The specific nomograms were built using the correlation between the prostatevo lume and some characteristic parameters of each BT modality, such as the source Air Kerma Strength, numberof implanted seeds in LDR or total radiation time in HDR. Results: For each institution and BT modality, nomograms normalized to the prescribed dose were obtained andfitted to a linear function. The parameters of the adjustment show a good agreement between data and the fitting.It should be noted that for each institution these linear function parameters are different, indicating that each centreshould construct its own nomograms. Conclusions: Nomograms for LDR and HDR prostate brachytherapy are simple quality assurance tools, specific foreach institution. Nevertheless, their use should be complementary to the necessary independent verification.

  8. Deep transfer learning of virtual endoluminal views for the detection of polyps in CT colonography

    Science.gov (United States)

    Näppi, Janne J.; Hironaka, Toru; Regge, Daniele; Yoshida, Hiroyuki

    2016-03-01

    Proper training of deep convolutional neural networks (DCNNs) requires large annotated image databases that are currently not available in CT colonography (CTC). In this study, we employed a deep transfer learning (DETALE) scheme to circumvent this problem in automated polyp detection for CTC. In our method, a DCNN that had been pre-trained with millions of non-medical images was adapted to identify polyps using virtual endoluminal images of the polyp candidates prompted by a computer-aided detection (CADe) system. For evaluation, 154 CTC cases with and without fecal tagging were divided randomly into a development set and an external validation set including 107 polyps >=6 mm in size. A CADe system was trained to detect polyp candidates using the development set, and the virtual endoluminal images of the polyp candidates were labeled manually into true-positive and several false-positive (FP) categories for transfer learning of the DCNN. Next, the trained CADe system was used to detect polyp candidates from the external validation set, and the DCNN reviewed their images to determine the final detections. The detection sensitivity of the standalone CADe system was 93% at 6.4 FPs per patient on average, whereas the DCNN reduced the number of FPs to 2.0 per patient without reducing detection sensitivity. Most of the remaining FP detections were caused by untagged stool. In fecal-tagged CTC cases, the detection sensitivity was 94% at only 0.78 FPs per patient on average. These preliminary results indicate that DETALE can yield substantial improvement in the accuracy of automated polyp detection in CTC.

  9. Local and systemic effects of endoluminal pelvic perfusion of isoproterenol: a dose response investigation in pigs.

    Science.gov (United States)

    Jakobsen, J S; Holst, U; Jakobsen, P; Steen, W; Mortensen, J

    2007-05-01

    Isoproterenol (Sygehus Apotekerne Danmark, Copenhagen, Denmark) is a beta-adrenergic agonist known to cause upper urinary tract relaxation. We studied the local effect on pelvic pressure and the systemic effects of endoluminal perfusion with isoproterenol in a porcine model. Pigs weighing 40 kg were studied. Catheters were placed in the renal pelvis for pressure measurement and perfusion, and a catheter was used to drain the bladder. Blood pressure and heart rate were recorded. In 6 pigs in group 1 the pelvic pressure increase was examined at increasing flow rates of 0, 2, 5, 8, 10 and 15 ml per minute with saline containing 0, 10(-3), 10(-2), 10(-1), 1 and 10 microg/ml isoproterenol. Blood values of isoproterenol were analyzed. In 6 pigs in group 2 the pelvis was perfused at a flow rate of 8 ml per minute with saline containing 0, 10(-5), 10(-4), 10(-3), 10(-2), 10(-1), 1 and 10 microg/ml isoproterenol. In group 1 endoluminal perfusion with isoproterenol inhibited the pelvic pressure increase due to perfusion at all concentrations of isoproterenol. At a perfusion rate of 8 ml per minute the maximal effect (a 78% decrease) was achieved using 0.1 microg/ml isoproterenol without cardiovascular side effects. In group 2 all isoproterenol concentrations caused significant inhibition of the pressure-flow relationship in a dose dependent matter. A 64% decrease in the pressure increase due to saline perfusion was achieved at 0.1 microg/ml isoproterenol without concomitant significant cardiovascular side effects. Isoproterenol was only detected in plasma during perfusion with 1 and 10 microg/ml isoproterenol, which caused significant cardiovascular side effects in the latter case. Isoproterenol significantly inhibits the pressure increase due to perfusion in the normal porcine renal pelvis without concomitant cardiovascular side effects. Isoproterenol is a safe drug in this porcine model and, hence, it is potentially useful during endourological procedures.

  10. Experimental investigations of an endoluminal ultrasound applicator for MR-guided thermal therapy of pancreatic cancer

    Science.gov (United States)

    Adams, Matthew; Salgaonkar, Vasant; Jones, Peter; Plata, Juan; Chen, Henry; Pauly, Kim Butts; Sommer, Graham; Diederich, Chris

    2017-03-01

    An MR-guided endoluminal ultrasound applicator has been proposed for palliative and potential curative thermal therapy of pancreatic tumors. Minimally invasive ablation or hyperthermia treatment of pancreatic tumor tissue would be performed with the applicator positioned in the gastrointestinal (GI) lumen, and sparing of the luminal tissue would be achieved with a water-cooled balloon surrounding the ultrasound transducers. This approach offers the capability of conformal volumetric therapy for fast treatment times, with control over the 3D spatial deposition of energy. Prototype endoluminal ultrasound applicators have been fabricated using 3D printed fixtures that seat two 3.2 or 5.6 MHz planar or curvilinear transducers and contain channels for wiring and water flow. Spiral surface coils have been integrated onto the applicator body to allow for device localization and tracking for therapies performed under MR guidance. Heating experiments with a tissue-mimicking phantom in a 3T MR scanner were performed and demonstrated capability of the prototype to perform volumetric heating through duodenal luminal tissue under real-time PRF-based MR temperature imaging (MRTI). Additional experiments were performed in ex vivo pig carcasses with the applicator inserted into the esophagus and aimed towards liver or soft tissue surrounding the spine under MR guidance. These experiments verified the capacity of heating targets up to 20-25 mm from the GI tract. Active device tracking and automated prescription of imaging and temperature monitoring planes through the applicator were made possible by using Hadamard encoded tracking sequences to obtain the coordinates of the applicator tracking coils. The prototype applicators have been integrated with an MR software suite that performs real-time device tracking and temperature monitoring.

  11. WE-F-BRD-01: HDR Brachytherapy II: Integrating Imaging with HDR

    Energy Technology Data Exchange (ETDEWEB)

    Craciunescu, O [Duke University Medical Center, Durham, NC (United States); Todor, D [Virginia Commonwealth University, Richmond, VA (United States); Leeuw, A de

    2014-06-15

    In recent years, with the advent of high/pulsed dose rate afterloading technology, advanced treatment planning systems, CT/MRI compatible applicators, and advanced imaging platforms, image-guided adaptive brachytherapy treatments (IGABT) have started to play an ever increasing role in modern radiation therapy. The most accurate way to approach IGABT treatment is to provide the infrastructure that combines in a single setting an appropriate imaging device, a treatment planning system, and a treatment unit. The Brachytherapy Suite is not a new concept, yet the modern suites are incorporating state-of-the-art imaging (MRI, CBCT equipped simulators, CT, and /or US) that require correct integration with each other and with the treatment planning and delivery systems. Arguably, an MRI-equipped Brachytherapy Suite is the ideal setup for real-time adaptive brachytherapy treatments. The main impediment to MRI-IGABT adoption is access to MRI scanners. Very few radiation oncology departments currently house MRI scanners, and even fewer in a dedicated Brachytherapy Suite. CBCT equipped simulators are increasingly offered by manufacturers as part of a Brachytherapy Suite installation. If optimized, images acquired can be used for treatment planning, or can be registered with other imaging modalities. This infrastructure is relevant for all forms of brachytherapy, especially those utilizing multi-fractionated courses of treatment such as prostate and cervix. Moreover, for prostate brachytherapy, US imaging systems can be part of the suite to allow for real-time HDR/LDR treatments. Learning Objectives: Understand the adaptive workflow of MR-based IGBT for cervical cancer. Familiarize with commissioning aspects of a CBCT equipped simulator with emphasis on brachytherapy applications Learn about the current status and future developments in US-based prostate brachytherapy.

  12. Modeling of endoluminal and interstitial ultrasound hyperthermia and thermal ablation: applications to device design, feedback control, and treatment planning

    Science.gov (United States)

    Prakash, Punit; Salgaonkar, Vasant A.; Diederich, Chris J.

    2014-01-01

    Endoluminal and catheter-based ultrasound applicators are currently under development and are in clinical use for minimally invasive hyperthermia and thermal ablation of various tissue targets. Computational models play a critical role in in device design and optimization, assessment of therapeutic feasibility and safety, devising treatment monitoring and feedback control strategies, and performing patient-specific treatment planning with this technology. The critical aspects of theoretical modeling, applied specifically to endoluminal and interstitial ultrasound thermotherapy, are reviewed. Principles and practical techniques for modeling acoustic energy deposition, bioheat transfer, thermal tissue damage, and dynamic changes in the physical and physiological state of tissue are reviewed. The integration of these models and applications of simulation techniques in identification of device design parameters, development of real time feedback-control platforms, assessing the quality and safety of treatment delivery strategies, and optimization of inverse treatment plans are presented. PMID:23738697

  13. Modelling of endoluminal and interstitial ultrasound hyperthermia and thermal ablation: applications for device design, feedback control and treatment planning.

    Science.gov (United States)

    Prakash, Punit; Salgaonkar, Vasant A; Diederich, Chris J

    2013-06-01

    Endoluminal and catheter-based ultrasound applicators are currently under development and are in clinical use for minimally invasive hyperthermia and thermal ablation of various tissue targets. Computational models play a critical role in device design and optimisation, assessment of therapeutic feasibility and safety, devising treatment monitoring and feedback control strategies, and performing patient-specific treatment planning with this technology. The critical aspects of theoretical modelling, applied specifically to endoluminal and interstitial ultrasound thermotherapy, are reviewed. Principles and practical techniques for modeling acoustic energy deposition, bioheat transfer, thermal tissue damage, and dynamic changes in the physical and physiological state of tissue are reviewed. The integration of these models and applications of simulation techniques in identification of device design parameters, development of real time feedback-control platforms, assessing the quality and safety of treatment delivery strategies, and optimisation of inverse treatment plans are presented.

  14. MO-B-BRC-00: Prostate HDR Treatment Planning - Considering Different Imaging Modalities

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2016-06-15

    Brachytherapy has proven to be an effective treatment option for prostate cancer. Initially, prostate brachytherapy was delivered through permanently implanted low dose rate (LDR) radioactive sources; however, high dose rate (HDR) temporary brachytherapy for prostate cancer is gaining popularity. Needle insertion during prostate brachytherapy is most commonly performed under ultrasound (U/S) guidance; however, treatment planning may be performed utilizing several imaging modalities either in an intra- or post-operative setting. During intra-operative prostate HDR, the needles are imaged during implantation, and planning may be performed in real time. At present, the most common imaging modality utilized for intra-operative prostate HDR is U/S. Alternatively, in the post-operative setting, following needle implantation, patients may be simulated with computed tomography (CT) or magnetic resonance imaging (MRI). Each imaging modality and workflow provides its share of benefits and limitations. Prostate HDR has been adopted in a number of cancer centers across the nation. In this educational session, we will explore the role of U/S, CT, and MRI in HDR prostate brachytherapy. Example workflows and operational details will be shared, and we will discuss how to establish a prostate HDR program in a clinical setting. Learning Objectives: Review prostate HDR techniques based on the imaging modality Discuss the challenges and pitfalls introduced by the three imagebased options for prostate HDR brachytherapy Review the QA process and learn about the development of clinical workflows for these imaging options at different institutions.

  15. Realistic camera noise modeling with application to improved HDR synthesis

    Science.gov (United States)

    Goossens, Bart; Luong, Hiêp; Aelterman, Jan; Pižurica, Aleksandra; Philips, Wilfried

    2012-12-01

    Due to the ongoing miniaturization of digital camera sensors and the steady increase of the "number of megapixels", individual sensor elements of the camera become more sensitive to noise, even deteriorating the final image quality. To go around this problem, sophisticated processing algorithms in the devices, can help to maximally exploit the knowledge on the sensor characteristics (e.g., in terms of noise), and offer a better image reconstruction. Although a lot of research focuses on rather simplistic noise models, such as stationary additive white Gaussian noise, only limited attention has gone to more realistic digital camera noise models. In this article, we first present a digital camera noise model that takes several processing steps in the camera into account, such as sensor signal amplification, clipping, post-processing,.. We then apply this noise model to the reconstruction problem of high dynamic range (HDR) images from a small set of low dynamic range (LDR) exposures of a static scene. In literature, HDR reconstruction is mostly performed by computing a weighted average, in which the weights are directly related to the observer pixel intensities of the LDR image. In this work, we derive a Bayesian probabilistic formulation of a weighting function that is near-optimal in the MSE sense (or SNR sense) of the reconstructed HDR image, by assuming exponentially distributed irradiance values. We define the weighting function as the probability that the observed pixel intensity is approximately unbiased. The weighting function can be directly computed based on the noise model parameters, which gives rise to different symmetric and asymmetric shapes when electronic noise or photon noise is dominant. We also explain how to deal with the case that some of the noise model parameters are unknown and explain how the camera response function can be estimated using the presented noise model. Finally, experimental results are provided to support our findings.

  16. : Light Steering Projection Systems and Attributes for HDR Displays

    KAUST Repository

    Damberg, Gerwin

    2017-06-02

    New light steering projectors in cinema form images by moving light away from dark regions into bright areas of an image. In these systems, the peak luminance of small features can far exceed full screen white luminance. In traditional projectors where light is filtered or blocked in order to give shades of gray (or colors), the peak luminance is fixed. The luminance of chromatic features benefit in the same way as white features, and chromatic image details can be reproduced at high brightness leading to a much wider overall color gamut coverage than previously possible. Projectors of this capability are desired by the creative community to aid in and enhance storytelling. Furthermore, reduced light source power requirements of light steering projectors provide additional economic and environmental benefits. While the dependency of peak luminance level on (bright) image feature size is new in the digital cinema space, display technologies with identical characteristics such as OLED, LED LCD and Plasma TVs are well established in the home. Similarly, direct view LED walls are popular in events, advertising and architectural markets. To enable consistent color reproduction across devices in today’s content production pipelines, models that describe modern projectors and display attributes need to evolve together with HDR standards and available metadata. This paper is a first step towards rethinking legacy display descriptors such as contrast, peak luminance and color primaries in light of new display technology. We first summarize recent progress in the field of light steering projectors in cinema and then, based on new projector and existing display characteristics propose the inclusion of two simple display attributes: Maximum Average Luminance and Peak (Color) Primary Luminance. We show that the proposed attributes allow a better prediction of content reproducibility on HDR displays. To validate this assertion, we test professional content on a commercial HDR

  17. HDR brachytherapy for superficial non-melanoma skin cancers.

    Science.gov (United States)

    Gauden, Ruth; Pracy, Martin; Avery, Anne-Marie; Hodgetts, Ian; Gauden, Stan

    2013-04-01

    Our initial experience using recommended high dose per fraction skin brachytherapy (BT) treatment schedules, resulted in poor cosmesis. This study aimed to assess in a prospective group of patients the use of Leipzig surface applicators for High Dose Rate (HDR) brachytherapy, for the treatment of small non-melanoma skin cancers (NMSC) using a protracted treatment schedule. Treatment was delivered by HDR brachytherapy with Leipzig applicators. 36 Gy, prescribed to between 3 to 4 mm, was given in daily 3 Gy fractions. Acute skin toxicity was evaluated weekly during irradiation using the Radiation Therapy Oncology Group criteria. Local response, late skin effects and cosmetic results were monitored at periodic intervals after treatment completion. From March 2002, 200 patients with 236 lesions were treated. Median follow-up was 66 months (range 25-121 months). A total of 162 lesions were macroscopic, while in 74 cases, BT was given after resection because of positive microscopic margins. There were 121 lesions that were basal cell carcinomas, and 115 were squamous cell carcinomas. Lesions were located on the head and neck (198), the extremities (26) and trunk (12). Local control was 232/236 (98%). Four patients required further surgery to treat recurrence. Grade 1 acute skin toxicity was detected in 168 treated lesions (71%) and grade 2 in 81 (34%). Cosmesis was good or excellent in 208 cases (88%). Late skin hypopigmentation changes were observed in 13 cases (5.5%). Delivering 36 Gy over 2 weeks to superficial NMSC using HDR brachytherapy is well tolerated and provides a high local control rate without significant toxicity. © 2012 The Authors. Journal of Medical Imaging and Radiation Oncology © 2012 The Royal Australian and New Zealand College of Radiologists.

  18. HDR IMAGING FOR FEATURE DETECTION ON DETAILED ARCHITECTURAL SCENES

    Directory of Open Access Journals (Sweden)

    G. Kontogianni

    2015-02-01

    Full Text Available 3D reconstruction relies on accurate detection, extraction, description and matching of image features. This is even truer for complex architectural scenes that pose needs for 3D models of high quality, without any loss of detail in geometry or color. Illumination conditions influence the radiometric quality of images, as standard sensors cannot depict properly a wide range of intensities in the same scene. Indeed, overexposed or underexposed pixels cause irreplaceable information loss and degrade digital representation. Images taken under extreme lighting environments may be thus prohibitive for feature detection/extraction and consequently for matching and 3D reconstruction. High Dynamic Range (HDR images could be helpful for these operators because they broaden the limits of illumination range that Standard or Low Dynamic Range (SDR/LDR images can capture and increase in this way the amount of details contained in the image. Experimental results of this study prove this assumption as they examine state of the art feature detectors applied both on standard dynamic range and HDR images.

  19. High Brightness HDR Projection Using Dynamic Freeform Lensing

    KAUST Repository

    Damberg, Gerwin

    2016-05-03

    Cinema projectors need to compete with home theater displays in terms of image quality. High frame rate and spatial resolution as well as stereoscopic 3D are common features today, but even the most advanced cinema projectors lack in-scene contrast and, more important, high peak luminance, both of which are essential perceptual attributes of images appearing realistic. At the same time, HDR image statistics suggest that the average image intensity in a controlled ambient viewing environment such as the cinema can be as low as 1% for cinematic HDR content and not often higher than 18%, middle gray in photography. Traditional projection systems form images and colors by blocking the source light from a lamp, therefore attenuating between 99% and 82% of light, on average. This inefficient use of light poses significant challenges for achieving higher peak brightness levels. In this work, we propose a new projector architecture built around commercially available components, in which light can be steered to form images. The gain in system efficiency significantly reduces the total cost of ownership of a projector (fewer components and lower operating cost), and at the same time increases peak luminance and improves black level beyond what is practically achievable with incumbent projector technologies. At the heart of this computational display technology is a new projector hardware design using phase modulation in combination with a new optimization algorithm that is capable of on-the-fly computation of freeform lens surfaces. © 2016 ACM.

  20. 4D Printing of Shape Memory-Based Personalized Endoluminal Medical Devices.

    Science.gov (United States)

    Zarek, Matt; Mansour, Nicola; Shapira, Shir; Cohn, Daniel

    2017-01-01

    The convergence of additive manufacturing and shape-morphing materials is promising for the advancement of personalized medical devices. The capability to transform 3D objects from one shape to another, right off the print bed, is known as 4D printing. Shape memory thermosets can be tailored to have a range of thermomechanical properties favorable to medical devices, but processing them is a challenge because they are insoluble and do not flow at any temperature. This study presents here a strategy to capitalize on a series of medical imaging modalities to construct a printable shape memory endoluminal device, exemplified by a tracheal stent. A methacrylated polycaprolactone precursor with a molecular weight of 10 000 g mol-1 is printed with a UV-LED stereolithography printer based on anatomical data. This approach converges with the zeitgeist of personalized medicine and it is anticipated that it will broadly expand the application of shape memory-exhibiting biomedical devices to myriad clinical indications. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Cosmetic effect in patients with early breast cancer treated with breast conserving therapy (BCT) and with HDR brachytherapy (HDR-BT) “boost”

    Science.gov (United States)

    Łyczek, Jarosław; Kawczyn´ska, Maria; Gruszczyn´ska, Ewelina

    2009-01-01

    Purpose The estimation of cosmetic effect in 93 patients with early breast cancer treated with breast conserving surgery (BCS) followed by combined radiotherapy, including HDR brachytherapy (HDR-BT) boost. Material and methods After BCS (tumorectomy or quadrantectomy) external beam radiation therapy (EBRT) was used in total dose of 50 Gy for the whole breast. Tumor bed was localized basing on clinical and mammographic preoperative examinations and histopathology evaluation. 10 Gy in one fraction was applied to all patients using HDR-BT. Steel interstitial needles stabilized by plastic templates were used. 192-Ir with 10 Ci nominal activity and HDR-GammaMed 12i unit (Mick Radio-Nuclear Instruments, Inc., Mt. Vernon, NY) and ABACUS software were used. 31 patients received additional chemotherapy. Cosmetic effect was evaluated in 36 month after the end of brachytherapy treatment basing on modified EORTC scale. For statistical analysis the rang of correlation test, contingent test, linear regression test and ProbRough rulet induction test were used. Results and Conclusions HDR-BT tolerance was good in most of the cases. Excellent and very good cosmetic effect was observed in 79 patients (85%). Statistically important correlations between following examined prognostic factors and cosmetics outcome were observed: clinical and mammographic tumor estimation, method of breast conserving surgery, type of skin incision, number of interstitial applicators, irradiated reference volume (PTV) and type of optimization method. No correlations with cosmetics effect were found in factors such as: age of patients, location of tumor or additional therapy. PMID:27795716

  2. Transition from LDR to HDR brachytherapy for cervical cancer: Evaluation of tumor control, survival, and toxicity.

    Science.gov (United States)

    Romano, K D; Pugh, K J; Trifiletti, D M; Libby, B; Showalter, T N

    In 2012, our institution transitioned from low-dose-rate (LDR) brachytherapy to high dose-rate (HDR) brachytherapy. We report clinical outcomes after brachytherapy for cervical cancer at our institution over a continuous 10-year period. From 2004 to 2014, 258 women (184 LDR and 74 HDR) were treated with tandem and ovoid brachytherapy in the multidisciplinary management of International Federation of Gynecology and Obstetrics Stages IA-IVB cervical cancer. Clinical and treatment-related prognostic factors including age, stage, smoking status, relevant doses, and toxicity data were recorded. Median followup for the LDR and HDR groups was 46 months and 12 months, respectively. The majority of patients (92%) received external beam radiotherapy as well as concurrent chemotherapy (83%) before the start of brachytherapy. For all stages, the 1-year local control and overall survival (OS) rates were comparable between the LDR and HDR groups (87% vs. 81%, p = 0.12; and 75% vs. 85%, p = 0.16), respectively. Factors associated with OS on multivariate analysis include age, stage, and nodal involvement. On multivariate analysis, severe toxicity (acute or chronic) was higher with HDR than LDR (24% vs. 10%, p = 0.04). Additional prognostic factors associated with increased severe toxicity include former/current smokers and total dose to lymph nodes. This comparative retrospective analysis of a large cohort of women treated with brachytherapy demonstrates no significant difference in OS or local control between the LDR and HDR. Acute and chronic toxicity increased shortly after the implementation of HDR, highlighting the importance of continued refinement of HDR methods, including integrating advanced imaging. Copyright © 2016 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  3. Evaluation of the effectiveness of HDR tone-mapping operators for photogrammetric applications

    Directory of Open Access Journals (Sweden)

    Rossella Suma

    2016-11-01

    Full Text Available The ability of High Dynamic Range (HDR imaging to capture the full range of lighting in a scene has meant that it is being increasingly used for Cultural Heritage (CH applications. Photogrammetric techniques allow the semi-automatic production of 3D models from a sequence of images. Current photogrammetric methods are not always effective in reconstructing images under harsh lighting conditions, as significant geometric details may not have been captured accurately within under- and over-exposed regions of the image. HDR imaging offers the possibility to overcome this limitation, however the HDR images need to be tone mapped before they can be used within existing photogrammetric algorithms. In this paper we evaluate four different HDR tone-mapping operators (TMOs that have been used to convert raw HDR images into a format suitable for state-of-the-art algorithms, and in particular keypoint detection techniques. The evaluation criteria used are the number of keypoints, the number of valid matches achieved and the repeatability rate. The comparison considers two local and two global TMOs. HDR data from four CH sites were used: Kaisariani Monastery (Greece, Asinou Church (Cyprus, Château des Baux (France and Buonconsiglio Castle (Italy.

  4. Developing a multispectral HDR imaging module for a BRDF measurement system

    Science.gov (United States)

    Kim, Duck Bong; Seo, Myoung Kook; Kim, Kang Yeon; Lee, Kwan H.

    2010-08-01

    Most recent bidirectional reflectance distribution function (BRDF) measurement systems are the image-based that consist of a light source, a detector, and curved samples. They are useful for measuring the reflectance properties of a material but they have two major drawbacks. They suffer from high cost of BRDF acquisition and also give inaccurate results due to the limited use of spectral bands. In this paper, we propose a novel multispectral HDR imaging system and its efficient characterization method. It combines two promising technologies: high dynamic range (HDR) imaging and multispectral imaging to measure BRDF. We perform a full spectral recovery using camera response curves for each wavelength band and its analysis. For this, we use an HDR camera to capture HDR images and a liquid crystal tunable filter (LCTF) to generate multi-spectral images. Our method can provide an accurate color reproduction of metameric objects as well as a saturated image. Our multi-spectral HDR imaging system provides a very fast data acquisition time and also gives a low system setup cost compared to previous multi-spectral imaging systems and point-based commercial spectroradiometers. We verify the color accuracy of our multi-spectral HDR imaging system in terms of human vision and metamerism using colorimetric and spectral metric.

  5. Endoluminal surgical triangulation 2.0: A new flexible surgical robot. Preliminary pre-clinical results with colonic submucosal dissection.

    Science.gov (United States)

    Légner, András; Diana, Michele; Halvax, Péter; Liu, Yu-Yin; Zorn, Lucile; Zanne, Philippe; Nageotte, Florent; De Mathelin, Michel; Dallemagne, Bernard; Marescaux, Jacques

    2017-09-01

    Complex intraluminal surgical interventions of the gastrointestinal tract are challenging due to the limitation of existing instruments. Our group has developed a master-slave robotic flexible endoscopic platform that provides instrument triangulation in an endoluminal environment. Colonic endoscopic submucosal dissections (ESD) were carried out in eight pigs. The robot was introduced transanally. A combination of adapted tele-operated instruments was used. Specimens were inspected and measured. Out of 18 ESDs in total, 12 were successfully completed. Among the completed procedures, two perforations and one system failure occurred and were managed intraoperatively. There was no major bleeding. Mean size of the removed specimens was 18.2 ± 9.8 cm(2) and mean total procedure time was 73 ± 35.5 min. Experimental colorectal ESDs using the flexible surgical robot were feasible and reflected a short learning curve. After some technical improvements the system might allow for a wider adoption of complex endoluminal surgical procedures. Copyright © 2017 John Wiley & Sons, Ltd.

  6. Endoluminal ultrasound applicator configurations utilizing deployable arrays, reflectors and lenses to augment and dynamically adjust treatment volume, gain, and depth

    Science.gov (United States)

    Adams, Matthew S.; Salgaonkar, Vasant A.; Sommer, Graham; Diederich, Chris J.

    2017-02-01

    Endoluminal high-intensity ultrasound offers spatially-precise thermal ablation of tissues adjacent to body lumens, but is constrained in treatment volume and penetration depth by the effective aperture of integrated transducers, which are limited in size to enable delivery through anatomical passages, endoscopic instrumentation, or laparoscopic ports. This study introduced and investigated three distinct endoluminal ultrasound applicator designs that can be delivered in a compact state then deployed or expanded at the target luminal site to increase the effective therapeutic aperture. The first design incorporated an array of planar transducers which could be unfolded at specific angles of convergence between the transducers. Two alternative designs consisted of fixed transducer sources surrounded by an expandable multicompartment balloon that contained acoustic reflector and dynamically-adjustable fluid lenses compartments. Parametric studies of acoustic output were performed across device design parameters via the rectangular radiator and secondary sources methods. Biothermal models were used to simulate resulting temperature distributions in three-dimensional heterogeneous tissue models. Simulations indicate that a deployable transducer array can increase volumetric coverage and penetration depth by 80% and 20%, respectively, while permitting more conformal thermal lesion shapes based on the degree of convergence between the transducers. The applicator designs incorporating reflector and fluid lenses demonstrated enhanced focal gain and penetration depth that increased with the diameter of the expanded reflector-lens balloon. Thermal simulations of assemblies with 12 mm compact profiles and 50 mm expanded balloon diameters demonstrated generation of localized thermal lesions at depths up to 10 cm in liver tissue.

  7. The curvHDR method for gating flow cytometry samples

    Directory of Open Access Journals (Sweden)

    Wand Matthew P

    2010-01-01

    Full Text Available Abstract Background High-throughput flow cytometry experiments produce hundreds of large multivariate samples of cellular characteristics. These samples require specialized processing to obtain clinically meaningful measurements. A major component of this processing is a form of cell subsetting known as gating. Manual gating is time-consuming and subjective. Good automatic and semi-automatic gating algorithms are very beneficial to high-throughput flow cytometry. Results We develop a statistical procedure, named curvHDR, for automatic and semi-automatic gating. The method combines the notions of significant high negative curvature regions and highest density regions and has the ability to adapt well to human-perceived gates. The underlying principles apply to dimension of arbitrary size, although we focus on dimensions up to three. Accompanying software, compatible with contemporary flow cytometry infor-matics, is developed. Conclusion The method is seen to adapt well to nuances in the data and, to a reasonable extent, match human perception of useful gates. It offers big savings in human labour when processing high-throughput flow cytometry data whilst retaining a good degree of efficacy.

  8. Dosimetric influence of hyaluronic acid in patients with prostate cancer treated with RT3D; Influencia dosimetrica del acido hialuronico en pacientes cancer de prostata tratados con RT3D externa+HDR braquiterapia

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, J.; Vazquez, J. A.; Garcia Blanco, A. S.; Gomez, F.; Montejo, A.; Raba, J. I.; Pacheco, M. T.; Cardenal Carro, J.; Mendigueren, M. A.

    2013-07-01

    This study aims to assess the influence on dosimetry by the introduction of hyaluronic acid and assess the need for the realization of a second CT scan and consequent re-planning of RT3D treatment. (Author)

  9. A Survey on the Acceptance and the Use of HDR Photography Among Croatian Photographers

    Directory of Open Access Journals (Sweden)

    Maja Strgar Kurecic

    2013-04-01

    Full Text Available The emerging field of high dynamic range (HDR imaging is directly linked to diverse existing disciplines such as radiometry, photometry, colorimetry and colour appearance - each dealing with specific aspects of light and its perception by humans. Although the idea is not new, it has not been widely used until just a few years ago when digital cameras gained popularity and the computers processing power increased significantly. Now this photographic technique is widely spread and used, but even more often – misused. A research was conducted by means of a questionnaire in order to get some actual information about how Croatian photographers see the HDR photography and how they employ it. The results of the survey proved that indeed a great interest exists in the technique, but that many photographers are scared away from the HDR photography because of the misconception that the artificial look is an unavoidable side effect of the HDR processing. The fact is, however, that the final HDR image is a result of the tone mapping process and post-corrections and adjustments, entirely dependent on the photographer’s intent and vision, as well as his understanding of various adjustments available. The results of the questionnaire have also pointed out to other widely spread misconceptions which are discussed in this paper.

  10. BrachyView, a novel in-body imaging system for HDR prostate brachytherapy: Experimental evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Safavi-Naeini, M.; Han, Z.; Alnaghy, S.; Cutajar, D.; Petasecca, M.; Lerch, M. L. F.; Rosenfeld, A. B., E-mail: anatoly@uow.edu.au [Centre for Medical Radiation Physics, University of Wollongong, Wollongong 2522 (Australia); Franklin, D. R. [Faculty of Engineering and Information Technology, University of Technology, Sydney 2007 (Australia); Bucci, J. [St George Hospital Cancer Care Centre, Kogarah 2217 (Australia); Carrara, M. [Fondazione IRCCS Istituto Nazionale dei Tumori, Milan 20133 (Italy); Zaider, M. [Memorial Sloan Kettering Cancer Center, New York, New York 10065 (United States)

    2015-12-15

    Purpose: This paper presents initial experimental results from a prototype of high dose rate (HDR) BrachyView, a novel in-body source tracking system for HDR brachytherapy based on a multipinhole tungsten collimator and a high resolution pixellated silicon detector array. The probe and its associated position estimation algorithms are validated and a comprehensive evaluation of the accuracy of its position estimation capabilities is presented. Methods: The HDR brachytherapy source is moved through a sequence of positions in a prostate phantom, for various displacements in x, y, and z. For each position, multiple image acquisitions are performed, and source positions are reconstructed. Error estimates in each dimension are calculated at each source position and combined to calculate overall positioning errors. Gafchromic film is used to validate the accuracy of source placement within the phantom. Results: More than 90% of evaluated source positions were estimated with an error of less than one millimeter, with the worst-case error being 1.3 mm. Experimental results were in close agreement with previously published Monte Carlo simulation results. Conclusions: The prototype of HDR BrachyView demonstrates a satisfactory level of accuracy in its source position estimation, and additional improvements are achievable with further refinement of HDR BrachyView’s image processing algorithms.

  11. Radioterapia adjuvante no tratamento do câncer de endométrio: experiência com a associação de radio-terapia externa e braquiterapia de alta taxa de dose Adjuvant radiation therapy for the treatment of endometrial cancer: experience with combination of external radiation therapy and high-dose rate brachytherapy

    Directory of Open Access Journals (Sweden)

    Michael Jenwei Chen

    2005-12-01

    Full Text Available OBJETIVO: Analisar, retrospectivamente, os resultados da radioterapia externa (RT combinada a braquiterapia de alta taxa de dose (BATD, adjuvantes à cirurgia para o carcinoma de endométrio. MATERIAIS E MÉTODOS: Avaliamos 141 pacientes tratados com RT e BATD adjuvantes à cirurgia, no período de janeiro de 1993 a janeiro de 2001. RT pélvica foi realizada com dose mediana de 45 Gy, e BATD realizada na dose mediana de 24 Gy, em quatro inserções semanais de 6 Gy. A idade mediana das pacientes foi de 63 anos e a distribuição por estádio clínico (EC foi: EC I (FIGO, 52,4%; EC II, 13,5%; EC III, 29,8%; EC IV, 4,3%. RESULTADOS: Com seguimento mediano de 53,7 meses, a sobrevida livre de doença (SLD em cinco anos foi: EC I, 88,0%; EC II, 70,8%; EC III, 55,1%; EC IV, 50,0% (p = 0,0003. A sobrevida global em cinco anos foi: EC I, 79,6%; EC II, 74,0%; EC III, 53,6%; EC IV, 100,0% (p = 0,0062. Fatores que influíram na SLD foram grau histológico e histologia seropapilífera. Dos 33 casos que apresentaram recidiva da doença, em 13 (9,2% esta ocorreu na pelve, vagina ou cúpula vaginal. RT + BATD do fundo vaginal permitiram o controle da doença em 90,8% dos casos. CONCLUSÃO: A RT exerce papel fundamental no controle loco-regional do câncer de endométrio e permite excelentes taxas de cura nos estádios iniciais. Para os estádios mais avançados, a falha terapêutica tende a ser a distância, sugerindo a necessidade de complementação terapêutica sistêmica, com introdução de novas modalidades de tratamento, em particular a quimioterapia.OBJECTIVE: To review the results of adjuvant external beam radiation therapy (EBRT combined with high-dose rate brachytherapy (HDR-BT for the treatment of endometrial carcinoma. MATERIALS AND METHODS: We retrospectively evaluated 141 patients treated with EBRT and HDR-BT after surgery between January 1993 and January 2001. EBRT was performed with a median dose of 45 Gy, and HDR-BT was performed with a

  12. Theoretical design and evaluation of endoluminal ultrasound applicators for thermal therapy of pancreatic cancer under image guidance

    Science.gov (United States)

    Adams, Matthew; Scott, Serena; Salgaonkar, Vasant; Sommer, Graham; Diederich, Chris

    2017-03-01

    An image-guided endoluminal ultrasound applicator has been proposed for palliative and potential curative thermal therapy of pancreatic tumors. By considering a directional transducer array of planar, tubular, or curvilinear transducers, this design offers the potential for fast volumetric therapy and 3D spatial control over the energy deposition profile. Treatment of pancreatic tumor tissue would be performed in a minimally invasive fashion with the applicator positioned in the gastrointestinal (GI) lumen, and sparing of the luminal wall would be achieved with a water-cooled balloon surrounding the transducers. A theoretical evaluation of this design was performed by developing a 3D acoustic and bioheat transfer model, with temperature and thermal dose solutions obtained using a FEM solver (COMSOL Multiphysics). Parametric studies were performed on a generalized anatomical model of the pancreas, tumor, and adjacent luminal wall to determine preferred transducer configurations and frequencies for maximizing lesion volume and penetration while sparing the luminal wall. Patient-specific models of pancreatic tumors were generated from CT studies and used to assess the feasibility of performing thermal ablation or hyperthermia on small (˜2 cm diameter) pancreatic head tumors with an endoluminal applicator positioned within the duodenum. Simulation results indicate lower transducer operating frequencies (1-3 MHz) are necessary to mitigate damage to the luminal wall, and a tradeoff between penetration depth and lesion volume emerges as the degree of focusing increases. For patient-specific ablation modeling of tumors within 30 mm of the luminal wall, approximately 95% of the volume could be ablated within 15 min using a planar or lightly focused transducer configuration without duodenal damage. Over 90% of the volume could be elevated above 40°C at steady state for hyperthermia applications (e.g., radiation sensitization, drug delivery) using a tubular transducer. For

  13. Error Analysis of non-TLD HDR Brachytherapy Dosimetric Techniques

    Science.gov (United States)

    Amoush, Ahmad

    The American Association of Physicists in Medicine Task Group Report43 (AAPM-TG43) and its updated version TG-43U1 rely on the LiF TLD detector to determine the experimental absolute dose rate for brachytherapy. The recommended uncertainty estimates associated with TLD experimental dosimetry include 5% for statistical errors (Type A) and 7% for systematic errors (Type B). TG-43U1 protocol does not include recommendation for other experimental dosimetric techniques to calculate the absolute dose for brachytherapy. This research used two independent experimental methods and Monte Carlo simulations to investigate and analyze uncertainties and errors associated with absolute dosimetry of HDR brachytherapy for a Tandem applicator. An A16 MicroChamber* and one dose MOSFET detectors† were selected to meet the TG-43U1 recommendations for experimental dosimetry. Statistical and systematic uncertainty analyses associated with each experimental technique were analyzed quantitatively using MCNPX 2.6‡ to evaluate source positional error, Tandem positional error, the source spectrum, phantom size effect, reproducibility, temperature and pressure effects, volume averaging, stem and wall effects, and Tandem effect. Absolute dose calculations for clinical use are based on Treatment Planning System (TPS) with no corrections for the above uncertainties. Absolute dose and uncertainties along the transverse plane were predicted for the A16 microchamber. The generated overall uncertainties are 22%, 17%, 15%, 15%, 16%, 17%, and 19% at 1cm, 2cm, 3cm, 4cm, and 5cm, respectively. Predicting the dose beyond 5cm is complicated due to low signal-to-noise ratio, cable effect, and stem effect for the A16 microchamber. Since dose beyond 5cm adds no clinical information, it has been ignored in this study. The absolute dose was predicted for the MOSFET detector from 1cm to 7cm along the transverse plane. The generated overall uncertainties are 23%, 11%, 8%, 7%, 7%, 9%, and 8% at 1cm, 2cm, 3cm

  14. IPIP: A New Approach to Inverse Planning for HDR Brachytherapy by Directly Optimizing Dosimetric Indices

    CERN Document Server

    Siauw, Timmy; Atamturk, Alper; Hsu, I-Chow; Pouliot, Jean; Goldberg, Ken

    2010-01-01

    Purpose: Many planning methods for high dose rate (HDR) brachytherapy treatment planning require an iterative approach. A set of computational parameters are hypothesized that will give a dose plan that meets dosimetric criteria. A dose plan is computed using these parameters, and if any dosimetric criteria are not met, the process is iterated until a suitable dose plan is found. In this way, the dose distribution is controlled by abstract parameters. The purpose of this study is to improve HDR brachytherapy planning by developing a new approach that directly optimizes the dose distribution based on dosimetric criteria. Method: We develop Inverse Planning by Integer Program (IPIP), an optimization model for computing HDR brachytherapy dose plans and a fast heuristic for it. We used our heuristic to compute dose plans for 20 anonymized prostate cancer patient image data sets from our clinic database. Dosimetry was evaluated and compared to dosimetric criteria. Results: Dose plans computed from IPIP satis?ed al...

  15. Color appearance and color rendering of HDR scenes: an experiment

    Science.gov (United States)

    Parraman, Carinna; Rizzi, Alessandro; McCann, John J.

    2009-01-01

    In order to gain a deeper understanding of the appearance of coloured objects in a three-dimensional scene, the research introduces a multidisciplinary experimental approach. The experiment employed two identical 3-D Mondrians, which were viewed and compared side by side. Each scene was subjected to different lighting conditions. First, we used an illumination cube to diffuse the light and illuminate all the objects from each direction. This produced a low-dynamicrange (LDR) image of the 3-D Mondrian scene. Second, in order to make a high-dynamic range (HDR) image of the same objects, we used a directional 150W spotlight and an array of WLEDs assembled in a flashlight. The scenes were significant as each contained exactly the same three-dimensional painted colour blocks that were arranged in the same position in the still life. The blocks comprised 6 hue colours and 5 tones from white to black. Participants from the CREATE project were asked to consider the change in the appearance of a selection of colours according to lightness, hue, and chroma, and to rate how the change in illumination affected appearance. We measured the light coming to the eye from still-life surfaces with a colorimeter (Yxy). We captured the scene radiance using multiple exposures with a number of different cameras. We have begun a programme of digital image processing of these scene capture methods. This multi-disciplinary programme continues until 2010, so this paper is an interim report on the initial phases and a description of the ongoing project.

  16. Transillumination and HDR Imaging for Proximal Caries Detection.

    Science.gov (United States)

    Lederer, A; Kunzelmann, K H; Hickel, R; Litzenburger, F

    2018-02-01

    The purpose was to develop an in vitro model for the validation of near-infrared transillumination (NIRT) for proximal caries detection, to enhance NIRT with high-dynamic-range imaging (HDRI), and to compare both methods, using micro-computed tomography (µCT) as a reference standard. Both proximal surfaces of 53 healthy or decayed permanent human teeth were examined using the Diagnocam (DC) (KaVo) and NIRT with HDRI (NIRT-HDRI). NIRT was combined with HDRI to improve the diagnostic performance by reducing under- and overexposed image areas. For NIRT-HDRI, an exposure series was captured and merged into a single HDR image. A classification was applied according to lesion depth. All surfaces were assessed twice by 2 trained examiners, and additionally with µCT for validation. The Kappa statistic was used to calculate inter-rater reliability and agreement between DC and NIRT-HDRI. Inter-rater reliability (weighted Kappa, wκ) showed very good agreement for the DC (0.90) and NIRT-HDRI (0.96). The overall agreement (wκ) was almost perfect (0.85). In the individual categories (0 to 4), the agreement (simple Kappa) ranged from almost perfect (category 4) to moderate (1 and 2) to substantial (categories 0 and 3). Sensitivity and specificity of sound surfaces, enamel, and dentin caries ranged from 0.57 to 0.99 and were similar for both methods in the different categories. NIRT-HDRI had a higher sensitivity for sound surfaces and enamel caries, as well as a higher specificity for dentin caries. Regarding the obtained images, HDRI allowed for the detection of caries within a greater range of luminance levels, resulting in a more detailed visualization of structures without under- or overexposure. However, HDRI this did not improve the diagnostics significantly. Distinguishing between a processed demineralized enamel and dentin lesions appears to be a problem specific to NIRT and cannot be balanced using HDRI.

  17. High dose-rate brachytherapy as a treatment option in primary tracheal tumors Braquiterapia de alta taxa de dose como opção terapêutica nos tumores primários da traquéia

    Directory of Open Access Journals (Sweden)

    Heloisa de Andrade Carvalho

    2005-08-01

    Full Text Available PURPOSE: To present experience with high dose-rate endobronchial brachytherapy in the treatment of primary tracheal tumors. PATIENTS AND METHODS: Four patients with nonresected primary tracheal tumors are presented: 2 cases of squamous cell carcinoma of the trachea, 1 of recurrent adenoid cystic carcinoma, and 1 with recurrent plasmacytoma. All received brachytherapy, alone or as a boost for primary irradiation, in 3 or 4 fractions of 7.5 Gy, calculated at a depth of 1 cm. Follow-up was considered to start from the end of brachytherapy. RESULTS: Local control was achieved in all cases at the time of first bronchoscopic evaluation. Two patients with squamous cell carcinoma died at 6th and 33rd months after brachytherapy, respectively. The first had no evidence of disease, and the latter had local recurrence. The other 2 patients were alive after 64 and 110 months of follow-up, respectively, both with no evidence of disease. Tracheal stenosis developed in these 2 cases, 22 and 69 months after brachytherapy. Tracheal stent placement was needed only for the patient with an adenoid cystic carcinoma. CONCLUSIONS: Endobronchial high dose-rate brachytherapy may be used for tracheal tumors, even as a boost for external beam irradiation, or in recurrences. Local control in 3 out of 4 patients indicates that individual cases may benefit from the treatment. Long-term survival may also be expected, mainly for tumors with adenoid cystic histology.OBJETIVO: Apresentar a experiência do tratamento de 4 pacientes com tumores primários de traquéia, não operados, submetidos à braquiterapia endobrônquica de alta taxa de dose. PACIENTES E MÉTODOS: Dois casos de carcinoma espinocelular, uma recidiva de carcinoma adenóide cístico e uma recidiva de plasmocitoma primário da traquéia. Todos receberam braquiterapia endobrônquica, exclusiva ou como reforço de dose da radioterapia externa. Foram administradas 3 ou 4 frações de 7,5 Gy cada, calculados a 1 cm de

  18. Trans-Pacific HDR Satellite Communications Experiment Phase-2 Project Plan and Experimental Network

    Science.gov (United States)

    Hsu, Eddie; Kadowaki, Naoto; Yoshimura, Naoko; Takahashi, Takashi; Yoshikawa, Makoto; Bergman, Larry; Bhasin, Kul

    2000-01-01

    The trans-Pacific high data rate (TP-HDR) satellite communications experiment was proposed at the Japan-U.S. Cooperation in Space (JUCS) Program Workshop held in Hawaii in 1993 and remote high definition video post-production was demonstrated as the first phase trial. ATM-based 45 Mbps trans-Pacific link was established in the first phase, and the following experiments with 155 Mbps was planned as the phase 2. This paper describes the experimental network configuration and project plan of TP-HDR experiment phase 2. Additional information is provided in the original.

  19. Braquiterapia com rutênio-106 em melanomas uveais - resultados preliminares: experiência uni-institucional Ruthenium-106 brachytherapy for uveal melanomas - preliminary results: a single institutional experience

    Directory of Open Access Journals (Sweden)

    Rodrigo Souza Dias

    2007-04-01

    Full Text Available OBJETIVO: Analisar os resultados preliminares da braquiterapia com rutênio-106 em pacientes portadores de melanomas uveais. MATERIAIS E MÉTODOS: No período de abril de 2002 a julho de 2003, 20 pacientes com diagnóstico de melanoma uveal foram tratados com braquiterapia com rutênio-106. A dose calculada no ápice tumoral variou de 55 Gy a 100 Gy. Pacientes com lesões com altura maior que 5 mm foram submetidos a termoterapia transpupilar concomitante à colocação da placa oftálmica. RESULTADOS: Quanto à localização da lesão, esta se encontrava na coróide em 75% dos casos, na íris em 15% e no corpo ciliar em 10% dos pacientes. Com seguimento mediano de 19 meses, a sobrevida livre de progressão para a braquiterapia e para a associação com a termoterapia transpupilar foi de 69% e 87%, respectivamente. Observou-se redução significante da altura tumoral após o tratamento. Nenhum dos pacientes foi submetido a enucleação. CONCLUSÃO: Nossos resultados preliminares mostram que a braquiterapia com rutênio-106 é uma opção adequada para o tratamento conservador de melanomas uveais em termos de controle local, manutenção do globo ocular e visão útil, com índice aceitável de complicações.OBJECTIVE: To analyze the early response of uveal melanomas in patients treated with ruthenium-106 brachytherapy. MATERIALS AND METHODS: In the period between April 2002 and July 2003, 20 patients diagnosed with uveal melanoma were submitted to ruthenium-106 brachytherapy. The calculated dose delivered at the apex of the tumor ranged between 55 Gy and 100 Gy. Patients with lesions greater than 5 mm were submitted to transpupillary thermotherapy concomitantly with ophthalmic plaque insertion. RESULTS: As regards the lesions site, 75% of the lesions were located in the choroid, 15% in the iris, and the remainder 10% in the ciliary body. In a median 19-month-follow-up, the progression-free survival for brachytherapy was 69%, and 87% for

  20. External radiation and HDR-brachytherapy in the treatment of breast cancer. Externe Bestrahlung und interstitielle HDR-Brachytherapie in der Bestrahlung des Mammakarzinoms

    Energy Technology Data Exchange (ETDEWEB)

    Track, C. (Abt. fuer Radioonkologie, Krankenhaus der Barmherzigen Schwestern, Linz (Austria)); Seewald, D.H. (Abt. fuer Radioonkologie, Krankenhaus der Barmherzigen Schwestern, Linz (Austria)); Zoidl, J.P. (Abt. fuer Radioonkologie, Krankenhaus der Barmherzigen Schwestern, Linz (Austria)); Hammer, J. (Abt. fuer Radioonkologie, Krankenhaus der Barmherzigen Schwestern, Linz (Austria))

    1994-04-01

    In the breast conserving management of mammary cancer a high-dose-rate (HDR)-Iridium-192 source is used for interstitial boosting of the primary tumor site after external radiotherapy. We want to show the clinical results and side effects and to demonstrate the safe use of a HDR source. From December 1984 until November 1988, 154 patients with breast cancer stage T1-2, N0-1 were treated by conservative surgery and radiation. A dose of 45 to 50 Gy was given to the whole breast by external radiotherapy, and the previous tumor area was boosted by an interstitial implant with Iridium-192 HDR. We applied 10 Gy in one or two fractions. The mean follow-up period of survivors is 76 months (range 57 to 107 months). In 36 patients failures occured: eight patients (5%) developed local recurrences, 31 patients (20%) had distant metastases, and 19 (12%) died with cancer. The Kaplan-Meier estimation for five year overall survival is 86.9%, for disease-specific survival 89.3%, for local control 95.8%, and for disease free survival 80.1%. The most frequent late effects were telangiectasia (11%), fibrotic masses in the previous tumor area (6.5%), and lymphedema of the arm (6.5%). No serious complications could be observed. (orig./MG)

  1. Resultados de la aplicación de braquiterapia en el melanoma de coroides Results of the use of brachytherapy in choroidal melanoma

    Directory of Open Access Journals (Sweden)

    Belmary Aragonés Cruz

    2006-12-01

    Full Text Available Con el objetivo de evaluar los resultados a largo plazo de la braquiterapia con implante epiescleral de iridio 192 en el melanoma de coroides, se realizó un estudio clínico retrospectivo-prospectivo, que abarcó un período de 10 años, cuyo universo estuvo constituido por 30 ojos de 30 pacientes (cada uno de ellos aportó un ojo. Como resultado se observó una reducción del volumen tumoral en el 96,6 % de los casos. Conservó o mejoró la visión en 63,3 % de los casos. El desprendimiento de retina y el glaucoma neovascular fueron las complicaciones más frecuentes. Se detectó metástasis en 3,3 % de los casos, relacionados con el tumor, pero no se detectaron fallecimientos. Solo 13,3 % requirió enucleación por recaída. Por lo cual se pudo concluir que la braquiterapia con iridio 192 constituye una variante terapéutica y eficaz, con buenos resultados de supervivencia (100 %, de conservación del globo ocular y de la agudeza visual, que ofrece al paciente mejor calidad de vidaWith the objective of assessing the long-term results of episcleral iridium-192 implant brachytherapy for choroidal melanoma, a prospective/retrospective clinical study was performed, which covered 30 eyes for a period of 10 years. As a consequence, a reduction of the tumor volume was observed in 95,6 % of cases, Vision was preserved or improved in 63,3 % of treated eyes. Retinal detachment and neovascular glaucoma were the most frequent complications. Metastasis was detected in 3,3 % but no one died. Only 13,3 % required enucleation due to a relapse. It was concluded that iridium-102 brachytherapy constitutes an efficient therapeutic variant, with good results in survival (100%, and eye ball and visual acuity preservation, which provides the patient with better quality of life

  2. Tratamiento combinado de los queloides mediante cirugía y braquiterapia Treatment of queloids with surgical resection and brachytherapy

    Directory of Open Access Journals (Sweden)

    J. Bisbal

    2009-12-01

    Full Text Available Presentamos nuestra experiencia en el tratamiento de los queloides mediante resección quirúrgica y radioterapia inmediata posterior. La radioterapia transforma el queloide en un tejido hipocelular, hipovascular e hipóxico, impidiendo la excesiva migración de fibroblastos. Si se administra la dosis adecuada de radiación, se consigue un equilibrio entre la formación de cicatriz y la proliferación excesiva de tejido, evitando la formación de queloide, sin impedir la cicatrización normal. Nuestro protocolo se divide en dos fases: la primera consiste en la exéresis del queloide mediante una incisión que sigue el trayecto del mismo, con un cuidadoso cierre en dos planos siendo siempre el superficial una sutura intradérmica. La segunda fase será la radioterapia, con dos modalidades posibles de tratamiento: 1- Braquiterapia (tratamiento a corta distancia, requiere la colocación de un catéter bajo la sutura, a través del cual se introduce una fuente radiactiva, normalmente Ir192. Se emplea especialmente en heridas longitudinales. 2- Radioterapia externa con electrones de baja energía. Se emplea en heridas complejas o extensas. Generalmente, dosis de 20 Gy. en 4 fracciones de 500 cGy, ofrecen excelentes resultados con mínimas secuelas o efectos secundarios. El volumen blanco debe incluir la herida quirúrgica más un margen de 4 mm. alrededor de ella. Con este procedimiento, hemos observado unos excelentes resultados, con un índice de recidivas inferior al 4%, y una mejora en los síntomas clínicos en el 100% de los casos. Como efectos secundarios observamos telangiectasias (15,4 % o cambios en la pigmentación cutánea (5,9%.We present our experience in treatment of keloid scars with surgical resection and immediately postoperative radiotherapy. Radiotherapy changes keloid into an hypocellular, hypovascular and hypotoxic tissue, avoiding the excessive migration of fibroblasts. If the suitable dose of radiation is delivered, balance

  3. Speedup of optimization-based approach to local backlight dimming of HDR displays

    DEFF Research Database (Denmark)

    Burini, Nino; Nadernejad, Ehsan; Korhonen, Jari

    2012-01-01

    Local backlight dimming in Liquid Crystal Displays (LCD) is a technique for reducing power consumption and simultaneously increasing contrast ratio to provide a High Dynamic Range (HDR) image reproduction. Several backlight dimming algorithms exist with focus on reducing power consumption, while...

  4. Prediction of HDR quality by combining perceptually transformed display measurements with machine learning

    Science.gov (United States)

    Choudhury, Anustup; Farrell, Suzanne; Atkins, Robin; Daly, Scott

    2017-09-01

    We present an approach to predict overall HDR display quality as a function of key HDR display parameters. We first performed subjective experiments on a high quality HDR display that explored five key HDR display parameters: maximum luminance, minimum luminance, color gamut, bit-depth and local contrast. Subjects rated overall quality for different combinations of these display parameters. We explored two models | a physical model solely based on physically measured display characteristics and a perceptual model that transforms physical parameters using human vision system models. For the perceptual model, we use a family of metrics based on a recently published color volume model (ICT-CP), which consists of the PQ luminance non-linearity (ST2084) and LMS-based opponent color, as well as an estimate of the display point spread function. To predict overall visual quality, we apply linear regression and machine learning techniques such as Multilayer Perceptron, RBF and SVM networks. We use RMSE and Pearson/Spearman correlation coefficients to quantify performance. We found that the perceptual model is better at predicting subjective quality than the physical model and that SVM is better at prediction than linear regression. The significance and contribution of each display parameter was investigated. In addition, we found that combined parameters such as contrast do not improve prediction. Traditional perceptual models were also evaluated and we found that models based on the PQ non-linearity performed better.

  5. A gEUD-based inverse planning technique for HDR prostate brachytherapy: feasibility study.

    Science.gov (United States)

    Giantsoudi, D; Baltas, D; Karabis, A; Mavroidis, P; Zamboglou, N; Tselis, N; Shi, C; Papanikolaou, N

    2013-04-01

    The purpose of this work was to study the feasibility of a new inverse planning technique based on the generalized equivalent uniform dose for image-guided high dose rate (HDR) prostate cancer brachytherapy in comparison to conventional dose-volume based optimization. The quality of 12 clinical HDR brachytherapy implants for prostate utilizing HIPO (Hybrid Inverse Planning Optimization) is compared with alternative plans, which were produced through inverse planning using the generalized equivalent uniform dose (gEUD). All the common dose-volume indices for the prostate and the organs at risk were considered together with radiobiological measures. The clinical effectiveness of the different dose distributions was investigated by comparing dose volume histogram and gEUD evaluators. Our results demonstrate the feasibility of gEUD-based inverse planning in HDR brachytherapy implants for prostate. A statistically significant decrease in D10 or/and final gEUD values for the organs at risk (urethra, bladder, and rectum) was found while improving dose homogeneity or dose conformity of the target volume. Following the promising results of gEUD-based optimization in intensity modulated radiation therapy treatment optimization, as reported in the literature, the implementation of a similar model in HDR brachytherapy treatment plan optimization is suggested by this study. The potential of improved sparing of organs at risk was shown for various gEUD-based optimization parameter protocols, which indicates the ability of this method to adapt to the user's preferences.

  6. A gEUD-based inverse planning technique for HDR prostate brachytherapy: Feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Giantsoudi, D. [Department of Radiological Sciences, University of Texas Health Sciences Center, San Antonio, Texas 78229 (United States); Department of Radiation Oncology, Francis H. Burr Proton Therapy Center, Boston, Massachusetts 02114 (United States); Baltas, D. [Department of Medical Physics and Engineering, Strahlenklinik, Klinikum Offenbach GmbH, 63069 Offenbach (Germany); Nuclear and Particle Physics Section, Physics Department, University of Athens, 15701 Athens (Greece); Karabis, A. [Pi-Medical Ltd., Athens 10676 (Greece); Mavroidis, P. [Department of Radiological Sciences, University of Texas Health Sciences Center, San Antonio, Texas 78299 and Department of Medical Radiation Physics, Karolinska Institutet and Stockholm University, 17176 (Sweden); Zamboglou, N.; Tselis, N. [Strahlenklinik, Klinikum Offenbach GmbH, 63069 Offenbach (Germany); Shi, C. [St. Vincent' s Medical Center, 2800 Main Street, Bridgeport, Connecticut 06606 (United States); Papanikolaou, N. [Department of Radiological Sciences, University of Texas Health Sciences Center, San Antonio, Texas 78299 (United States)

    2013-04-15

    Purpose: The purpose of this work was to study the feasibility of a new inverse planning technique based on the generalized equivalent uniform dose for image-guided high dose rate (HDR) prostate cancer brachytherapy in comparison to conventional dose-volume based optimization. Methods: The quality of 12 clinical HDR brachytherapy implants for prostate utilizing HIPO (Hybrid Inverse Planning Optimization) is compared with alternative plans, which were produced through inverse planning using the generalized equivalent uniform dose (gEUD). All the common dose-volume indices for the prostate and the organs at risk were considered together with radiobiological measures. The clinical effectiveness of the different dose distributions was investigated by comparing dose volume histogram and gEUD evaluators. Results: Our results demonstrate the feasibility of gEUD-based inverse planning in HDR brachytherapy implants for prostate. A statistically significant decrease in D{sub 10} or/and final gEUD values for the organs at risk (urethra, bladder, and rectum) was found while improving dose homogeneity or dose conformity of the target volume. Conclusions: Following the promising results of gEUD-based optimization in intensity modulated radiation therapy treatment optimization, as reported in the literature, the implementation of a similar model in HDR brachytherapy treatment plan optimization is suggested by this study. The potential of improved sparing of organs at risk was shown for various gEUD-based optimization parameter protocols, which indicates the ability of this method to adapt to the user's preferences.

  7. The conception and implementation of a local HDR fusion algorithm depending on contrast and luminosity parameters

    Science.gov (United States)

    Besrour, Amine; Abdelkefi, Fatma; Siala, Mohamed; Snoussi, Hichem

    2015-09-01

    Nowadays, the high dynamic range (HDR) imaging represents the subject of the most researches. The major problem lies in the implementation of the best algorithm to acquire the best video quality. In fact, the major constraint is to conceive an optimal fusion which must meet the rapid movement of video frames. The implemented merging algorithms were not quick enough to reconstitute the HDR video. In this paper, we detail each of the previous existing works before detailing our algorithm and presenting results from the acquired HDR images, tone mapped with various techniques. Our proposed algorithm guarantees a more enhanced and faster solution compared to the existing ones. In fact, it has the ability to calculate the saturation matrix related to the saturation rate of the neighboring pixels. The computed coefficients are affected respectively to each picture from the tested ones. This analysis provides faster and efficient results in terms of quality and brightness. The originality of our work remains on its processing method including the pixels saturation in the totality of the captured pictures and their combination in order to obtain the best pictures illustrating all the possible details. These parameters are computed for each zone depending on the contrast and the luminosity of the current pixel and its neighboring. The final HDR image's coefficients are calculated dynamically ensuring the best image quality equilibrating the brightness and contrast values and making the perfect final image.

  8. Mixed integer programming improves comprehensibility and plan quality in inverse optimization of prostate HDR Brachytherapy

    NARCIS (Netherlands)

    Gorissen, B.L.; den Hertog, D.; Hoffmann, A.L.

    2013-01-01

    Current inverse treatment planning methods that optimize both catheter positions and dwell times in prostate HDR brachytherapy use surrogate linear or quadratic objective functions that have no direct interpretation in terms of dose-volume histogram (DVH) criteria, do not result in an optimum or

  9. Dwell time modulation restrictions do not necessarily improve treatment plan quality for prostate HDR brachytherapy

    NARCIS (Netherlands)

    Balvert, M.; Gorissen, B.L.; den Hertog, D.; Hoffmann, A.L.

    Inverse planning algorithms for dwell time optimisation in interstitial high-dose-rate (HDR) brachytherapy may produce solutions with large dwell time variations within catheters, which may result in undesirable selective high-dose subvolumes. Extending the dwell time optimisation model with a dwell

  10. An automated optimization tool for high-dose-rate (HDR) prostate brachytherapy with divergent needle pattern

    NARCIS (Netherlands)

    Borot, Maxence; Maenhout, M.; de Senneville, B. Denis; Hautvast, G.; Binnekamp, D.; Lagendijk, J. J. W.; van Vulpen, M.; Moerland, M. A.

    2015-01-01

    Focal high-dose-rate (HDR) for prostate cancer has gained increasing interest as an alternative to whole gland therapy as it may contribute to the reduction of treatment related toxicity. For focal treatment, optimal needle guidance and placement is warranted. This can be achieved under MR guidance.

  11. An HDR imaging method with DTDI technology for push-broom cameras

    Science.gov (United States)

    Sun, Wu; Han, Chengshan; Xue, Xucheng; Lv, Hengyi; Shi, Junxia; Hu, Changhong; Li, Xiangzhi; Fu, Yao; Jiang, Xiaonan; Huang, Liang; Han, Hongyin

    2017-11-01

    Conventionally, high dynamic-range (HDR) imaging is based on taking two or more pictures of the same scene with different exposure. However, due to a high-speed relative motion between the camera and the scene, it is hard for this technique to be applied to push-broom remote sensing cameras. For the sake of HDR imaging in push-broom remote sensing applications, the present paper proposes an innovative method which can generate HDR images without redundant image sensors or optical components. Specifically, this paper adopts an area array CMOS (complementary metal oxide semiconductor) with the digital domain time-delay-integration (DTDI) technology for imaging, instead of adopting more than one row of image sensors, thereby taking more than one picture with different exposure. And then a new HDR image by fusing two original images with a simple algorithm can be achieved. By conducting the experiment, the dynamic range (DR) of the image increases by 26.02 dB. The proposed method is proved to be effective and has potential in other imaging applications where there is a relative motion between the cameras and scenes.

  12. Optimization in brachytherapy with the implementation of Radiobiology; Optimizacion en Braquiterapia con la implementacion de la Radiobiologia

    Energy Technology Data Exchange (ETDEWEB)

    Duran, M.P.; Bourel, V.J.; Rodriguez, I.; Torre, M. de la; Caneva, S. [Braqui S.R.L. Viamonte 1861, Buenos Aires (Argentina)

    1998-12-31

    In the brachytherapy planning treatments with High dose rates (HDR), the optimization algorithms used are based in dosimetric considerations and/or geometric ones, ignoring the radiobiological response of the tissue treated. In this work we wish to show the implementation of radiobiological concepts in the optimization. Assuming that the subtiles differences that result in the dose distribution among the different optimization models which are not visible in an isodose plane, it is studied how is classically make it , the quality implant through natural histograms about dose volumes and the resulting parameters. Also is studied the necrosis probability which may be caused by the choice of some optimization model, allowing with this the choice of the best implant. (Author)

  13. Effectiveness of two different HDR brachytherapy regimens with the same BED value in cervical cancer

    Directory of Open Access Journals (Sweden)

    Rajesh Vashistha

    2010-07-01

    Full Text Available Purpose: To analyze the effectiveness of biologically effective dose (BED in two different regimens of HDR brachytherapy keeping the same total BED to point A and to compare the relationship of overall treatment time in terms of local control and bladder and rectal complications.Material and methods: The study included two groups comprising a total of 90 cervical cancer patients who underwent external beam radiotherapy (EBRT followed by HDR intracavitary brachytherapy (ICBT. EBRT treatment was delivered by a Co-60 teletherapy unit to a prescribed dose of 45 Gy with 1.8 Gy per fraction in 25 fractions over a period of five weeks. Parallel opposed anterior–posterior (AP/PA fields with no central shielding were used, followed by the HDR ICBT dose, to point A, of either two fractions of 9.5 Gy with a gap of 10 days, or three fractions of 7.5 Gy with a gap of 7 days between the fractions. Gemcitabine (dose of 150 mg/m2 was given weekly to all the patients as a radiosensitizer. The calculate BED3 to point A was almost the same in both groups to keep the same late complication rates. The doses, and BED10 and BED3, were calculated at different bladder and rectal point as well as at the lymphatictrapezoid points. During and after treatment patients were evaluated for local control and complications for 24 months.Results and Conclusions: Doses and BEDs at different bladder, rectal and lymphatic trapezoid points, local control, and complications in both HDR ICBT groups did not have statistically significant differences (p > 0.05. Both HDR ICBT schedules are well tolerable and equally effective.

  14. SU-E-T-574: Fessiblity of Using the Calypso System for HDR Interstitial Catheter Reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Li, J S; Ma, C [Fox Chase Cancer Center, Philadelphia, PA (United States)

    2014-06-01

    Purpose: It is always a challenge to reconstruct the interstitial catheter for high dose rate (HDR) brachytherapy on patient CT or MR images. This work aims to investigate the feasibility of using the Calypso system (Varian Medical, CA) for HDR catheter reconstruction utilizing its accuracy on tracking the electromagnetic transponder location. Methods: Experiment was done with a phantom that has a HDR interstitial catheter embedded inside. CT scan with a slice thickness of 1.25 mm was taken for this phantom with two Calypso beacon transponders in the catheter. The two transponders were connected with a wire. The Calypso system was used to record the beacon transponders’ location in real time when they were gently pulled out with the wire. The initial locations of the beacon transponders were used for registration with the CT image and the detected transponder locations were used for the catheter path reconstruction. The reconstructed catheter path was validated on the CT image. Results: The HDR interstitial catheter was successfully reconstructed based on the transponders’ coordinates recorded by the Calypso system in real time when the transponders were pulled in the catheter. After registration with the CT image, the shape and location of the reconstructed catheter are evaluated against the CT image and the result shows an accuracy of 2 mm anywhere in the Calypso detectable region which is within a 10 cm X 10 cm X 10 cm cubic box for the current system. Conclusion: It is feasible to use the Calypso system for HDR interstitial catheter reconstruction. The obstacle for its clinical usage is the size of the beacon transponder whose diameter is bigger than most of the interstitial catheters used in clinic. Developing smaller transponders and supporting software and hardware for this application is necessary before it can be adopted for clinical use.

  15. Validity of the formalism of calculation in surface TG-43 brachytherapy high dose rate; Validez del formalismo de calculo del TG-43 en braquiterapia superficial con alta tase de dosis

    Energy Technology Data Exchange (ETDEWEB)

    Granero, D.; Perez-Calatayud, J.; Vijande, J.; Ballester, F.; Rivard, M. J.

    2013-07-01

    The purpose of this work is to evaluate the clinical implications and limitations in implant surface with a source of HDR very close or in contact with the surface of the skin, also studied the effect of bolus on the implant. The two available radionuclides have been studied commercially in HDR, Ir-192 and Co-60 units. (Author)

  16. Stomach position in prediction of survival in left-sided congenital diaphragmatic hernia with or without fetoscopic endoluminal tracheal occlusion.

    Science.gov (United States)

    Cordier, A-G; Jani, J C; Cannie, M M; Rodó, C; Fabietti, I; Persico, N; Saada, J; Carreras, E; Senat, M-V; Benachi, A

    2015-08-01

    To investigate the value of fetal stomach position in predicting postnatal outcome in left-sided congenital diaphragmatic hernia (CDH) with and without fetoscopic endoluminal tracheal occlusion (FETO). This was a retrospective review of CDH cases that were expectantly managed or treated with FETO, assessed from May 2008 to October 2013, in which we graded, on a scale of 1-4, stomach position on the four-chamber view of the heart with respect to thoracic structures. Logistic regression analysis was used to investigate the effect of management center (Paris, Brussels, Barcelona, Milan), stomach grading, observed-to-expected lung area-to-head circumference ratio (O/E-LHR), gestational age at delivery, birth weight in expectantly managed CDH, gestational ages at FETO and at removal and period of tracheal occlusion, on postnatal survival in CDH cases treated with FETO. We identified 67 expectantly managed CDH cases and 47 CDH cases that were treated with FETO. In expectantly managed CDH, stomach position and O/E-LHR predicted postnatal survival independently. In CDH treated with FETO, stomach position and gestational age at delivery predicted postnatal survival independently. In left-sided CDH with or without FETO, stomach position is predictive of postnatal survival. Copyright © 2014 ISUOG. Published by John Wiley & Sons Ltd.

  17. A prospective cohort study to compare treatment results between 2 fractionation schedules of high-dose-rate intracavitary brachytherapy (HDR-ICBT) in patients with cervical cancer.

    Science.gov (United States)

    Huang, Eng-Yen; Sun, Li-Min; Lin, Hao; Lan, Jen-Hong; Chanchien, Chan-Chao; Huang, Yu-Jie; Wang, Chang-Yu; Wang, Chong-Jong

    2013-01-01

    To compare the treatment results of 2 fractionation schedules for high-dose-rate intracavitary brachytherapy (HDR-ICBT) in patients with cervical cancer. From June 2001 through January 2008, 267 patients with stage IB-IVA cervical cancer were enrolled in the study. All patients underwent 4-field pelvic irradiation and HDR-ICBT. The median central and parametrial doses were 39.6 Gy and 45 Gy, respectively. Patient underwent either 6 Gy×4 (HDR-4) (n=144) or 4.5 Gy×6 (HDR-6) (n=123) to point A of ICBT using 192Ir isotope twice weekly. The rates of overall survival, locoregional failure, distant metastasis, proctitis, cystitis, and enterocolitis were compared between HDR-4 and HDR-6. There were no significant differences in the demographic data between HDR-4 and HDR-6 except for total treatment time. The 5-year proctitis rates were 23.0% and 21.5% in HDR-4 and HDR-6 (P=.399), respectively. The corresponding rates of grade 2-4 proctitis were 18.7% and 9.6% (P=.060). The corresponding rates of grades 3-4 proctitis were 5.2% and 1.3% (P=.231). Subgroup analysis revealed that HDR-4 significantly increased grade 2-4 proctitis in patients aged≥62 years old (P=.012) but not in patients agedschedules. The small fraction size of HDR-ICBT is associated with grade 2 proctitis without compromise of prognosis in elderly patients. This schedule is suggested for patients who tolerate an additional 2 applications of HDR-ICBT. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. The methodology proposed to estimate the absorbed dose at the entrance of the labyrinth in HDR brachytherapy facilities with IR-192; Propuesta de metodologia para estimar la dosis absorbida en la entrada del laberinto en instalaciones de braquiterapia HDR con Ir-192

    Energy Technology Data Exchange (ETDEWEB)

    Pujades, M. C.; Perez-Calatayud, J.; Ballester, F.

    2012-07-01

    In the absence of procedure for evaluating the design of a brachytherapy (BT) vault with maze from the point of view of radiation protection, usually formalism of external radiation is adapted. The purpose of this study is to adapt the methodology described by the National council on Radiological Protection and Measurements Report 151 (NCRP 151). Structural Shielding Design for megavoltage X-and Gamma-Ray Radiotherapy facilities, for estimating dose at the door in BT and its comparison with the results megavoltage X-and Gamma-Ray Radiotherapy Facilities, for estimating dose at the door in BT and its comparison with the results obtained by the method of Monte Carlo (MC) for a special case of bunker. (Author) 17 refs.

  19. Comparison between TG-43 dosimetry and Monte Carlo calculations using the FLAP Freiburg applicator for skin treatments with HDR brachytherapy; Comparacion dosimetrica entre TG-43 y calculos Monte Carlo usando el aplicador Freiburg Flap para tratamiento de piel con braquiterapia HDR

    Energy Technology Data Exchange (ETDEWEB)

    Vijande, J.; Ballester, F.; Granero, D.; Pujades, M. c.; Perez-Calatayud, J.; Lliso, F.; Carmona, V.; Camacho, C.

    2011-07-01

    The objective of this study is to compare the dose administered, both the skin surface and the depth limitation (5 mm) obtained using the data of TG-43 (under conditions of total dispersion in water) with that obtained calculations using Monte Carlo (MC) (taking into account both the air surrounding the FF, as its density and composition). Of special interest is the assessment of the possible existence of a defect of dispersion in the skin.

  20. Genetic characterization of the hdrRM operon: a novel high-cell-density-responsive regulator in Streptococcus mutans.

    Science.gov (United States)

    Merritt, Justin; Zheng, Lanyan; Shi, Wenyuan; Qi, Fengxia

    2007-08-01

    Many species of bacteria can adhere to surfaces and grow as sessile communities. The continued accumulation of bacteria can eventually lead to the extremely high-cell-density environment characteristic of many biofilms or cell colonies. This is the normal habitat of the cariogenic species Streptococcus mutans, which normally resides in the high-cell-density, multispecies community commonly referred to as dental plaque. Previous work has demonstrated that the transcription of two separate bacteriocins can be activated by the high-cell-density conditions created through the centrifugation and incubation of cell pellets. In this study, we identified an uncharacterized two-gene operon that was induced >10-fold by conditions of high cell density. The genes of the operon encode a putative transcription regulator and a membrane protein, which were renamed as hdrR and hdrM, respectively. A transcription fusion to the hdrRM operon confirmed its induction by high cell density. Mutation of hdrM abolished bacteriocin production, greatly increased natural competence, reduced the growth rate, and severely affected biofilm formation. Interestingly, no obvious phenotypes were observed from a non-polar mutation of hdrR or mutations affecting the entire operon. These data suggest that the hdrRM operon may constitute a novel regulatory system responsible for mediating a cellular response to a high-cell-density environment.

  1. HDR Pathological Image Enhancement Based on Improved Bias Field Correction and Guided Image Filter

    Science.gov (United States)

    Zhu, Ganzheng; Li, Siqi; Gong, Shang; Yang, Benqiang; Zhang, Libo

    2016-01-01

    Pathological image enhancement is a significant topic in the field of pathological image processing. This paper proposes a high dynamic range (HDR) pathological image enhancement method based on improved bias field correction and guided image filter (GIF). Firstly, a preprocessing including stain normalization and wavelet denoising is performed for Haematoxylin and Eosin (H and E) stained pathological image. Then, an improved bias field correction model is developed to enhance the influence of light for high-frequency part in image and correct the intensity inhomogeneity and detail discontinuity of image. Next, HDR pathological image is generated based on least square method using low dynamic range (LDR) image, H and E channel images. Finally, the fine enhanced image is acquired after the detail enhancement process. Experiments with 140 pathological images demonstrate the performance advantages of our proposed method as compared with related work. PMID:28116303

  2. Dosimetric study of surface applicators of HDR brachytherapy GammaMed Plus equipment

    Energy Technology Data Exchange (ETDEWEB)

    Reyes-Rivera, E., E-mail: eric-1985@fisica.ugto.mx, E-mail: modesto@fisica.ugto.mx, E-mail: uvaldoreyes@fisica.ugto.mx; Sosa, M., E-mail: eric-1985@fisica.ugto.mx, E-mail: modesto@fisica.ugto.mx, E-mail: uvaldoreyes@fisica.ugto.mx; Reyes, U., E-mail: eric-1985@fisica.ugto.mx, E-mail: modesto@fisica.ugto.mx, E-mail: uvaldoreyes@fisica.ugto.mx; Jesús Bernal-Alvarado, José de, E-mail: bernal@fisica.ugto.mx, E-mail: theo@fisica.ugto.mx, E-mail: gil@fisica.ugto.mx; Córdova, T., E-mail: bernal@fisica.ugto.mx, E-mail: theo@fisica.ugto.mx, E-mail: gil@fisica.ugto.mx; Gil-Villegas, A., E-mail: bernal@fisica.ugto.mx, E-mail: theo@fisica.ugto.mx, E-mail: gil@fisica.ugto.mx [División de Ciencias e Ingenierías, Universidad de Guanajuato, 37150 León, Gto. (Mexico); Monzón, E., E-mail: emonzon@imss.gob.mx [Unidad de Alta Especialidad No.1, Instituto Mexicano del Seguro Social, Léon, Gto. (Mexico)

    2014-11-07

    The cone type surface applicators used in HDR brachytherapy for treatment of small skin lesions are an alternative to be used with both electron beams and orthovoltage X-ray equipment. For a good treatment planning is necessary to know the dose distribution of these applicators, which can be obtained by experimental measurement and Monte Carlo simulation as well. In this study the dose distribution of surface applicators of 3 and 3.5 cm diameter, respectively of HDR brachytherapy GammaMed Plus equipment has been estimated using the Monte Carlo method, MCNP code. The applicators simulated were placed on the surface of a water phantom of 20 × 20 × 20 cm and the dose was calculated at depths from 0 to 3 cm with increments of 0.25 mm. The dose profiles obtained at depth show the expected gradients for surface therapy.

  3. Dosimetric study of surface applicators of HDR brachytherapy GammaMed Plus equipment

    Science.gov (United States)

    Reyes-Rivera, E.; Sosa, M.; Reyes, U.; Monzón, E.; de Jesús Bernal-Alvarado, José; Córdova, T.; Gil-Villegas, A.

    2014-11-01

    The cone type surface applicators used in HDR brachytherapy for treatment of small skin lesions are an alternative to be used with both electron beams and orthovoltage X-ray equipment. For a good treatment planning is necessary to know the dose distribution of these applicators, which can be obtained by experimental measurement and Monte Carlo simulation as well. In this study the dose distribution of surface applicators of 3 and 3.5 cm diameter, respectively of HDR brachytherapy GammaMed Plus equipment has been estimated using the Monte Carlo method, MCNP code. The applicators simulated were placed on the surface of a water phantom of 20 × 20 × 20 cm and the dose was calculated at depths from 0 to 3 cm with increments of 0.25 mm. The dose profiles obtained at depth show the expected gradients for surface therapy.

  4. Quality control for cervical cancer treatments on Hdr brachytherapy with Ir-192

    Energy Technology Data Exchange (ETDEWEB)

    Alvarino B, G.; Cogollo P, R.; Paez M, M., E-mail: lvarinog@hotmail.com [Universidad de Cordoba, Physics and Electronics Department, Carrera 6 No. 76-103, Monteria, Cordoba (Colombia)

    2013-10-01

    This work, developed at the National Cancer Institute in partnership with Universidad Nacional de Colombia located in Bogota, Colombia, presents the results of simulations of cervical cancer treatments, on Hdr brachytherapy with Ir-192, using as a physical simulator a natural female pelvis bone with soft tissue elaborated with the experimental material JJT. The doses were measured experimentally, prior to dosimetric characterization, with crystal thermoluminescence 100 LiF: Mg, Ti, located in the organs at risk: rectum and bladder. On the other hand, these treatments were planned and calculated theoretically by the system Micro-Selectron Hdr, with Plato brachytherapy software V 14.1 from the Netherlands Nucletron, and doses obtained in the same organs were compared with experimental results using dosimeters. The comparison of these results shows the correlation degree between the planning of dosimetric treatments and the experimental results, making the process in a form of quality control in vivo, of this type of procedure. (Author)

  5. High-dose-rate (HDR) brachytherapy for the treatment of benign obstructive endobronchial granulation tissue.

    Science.gov (United States)

    Madu, Chika N; Machuzak, Michael S; Sterman, Daniel H; Musani, Ali; Ahya, Vivek; McDonough, James; Metz, James M

    2006-12-01

    Severe airway obstruction can occur in the setting of benign granulation tissue forming at bronchial anastomotic sites after lung transplantation in up to 20% of patients. Many of these benign lesions respond to stent placement, laser ablation, or balloon bronchoplasty. However, in certain cases, proliferation of granulation tissue may persist despite all therapeutic attempts. This study describes a series of refractory patients treated with high-dose-rate (HDR) brachytherapy for benign proliferation of granulation tissue, causing airway compromise. Between April 2002 and June 2005, 5 patients with significant airway compromise from recurrent granulation tissue were treated with HDR brachytherapy. All patients had previously failed to maintain a patent airway despite multiple bronchoscopic interventions. Treatment was delivered using an HDR brachytherapy afterloader with (192)Ir. Dose prescription was to a depth of 1 cm. All patients were treated weekly, with total doses ranging from 10 Gy to 21 Gy in two to three fractions. The median follow-up was 12 months. All patients experienced a reduction in therapeutic bronchoscopic procedures after HDR brachytherapy compared with the pretreatment period. With the exception of possible radiation-induced bronchitis in 1 patient, there were no other treatment related complications. At the time of this report, 2 patients have died and the other 3 are alive with marked symptomatic improvement and reduced bronchoscopic procedures. High-dose-rate brachytherapy is an effective treatment for benign proliferation of granulation tissue causing airway obstruction. The early response to therapy is encouraging and further follow-up is necessary to determine long-term durability and late effects.

  6. IPIP: A new approach to inverse planning for HDR brachytherapy by directly optimizing dosimetric indices

    Energy Technology Data Exchange (ETDEWEB)

    Siauw, Timmy; Cunha, Adam; Atamtuerk, Alper; Hsu, I-Chow; Pouliot, Jean; Goldberg, Ken [Department of Civil and Environmental Engineering, University of California, Berkeley, 760 Davis Hall, Berkeley, California 94720-1710 (United States); Department of Radiation Oncology, University of California, San Francisco, Comprehensive Cancer Center, 1600 Divisadero Street, Suite H1031, San Francisco, California 94143-1708 (United States); Department of Industrial Engineering and Operations, University of California, Berkeley, 4141 Etcheverry Hall, Berkeley, California 94720-1777 (United States); Department of Radiation Oncology, University of California, San Francisco, Comprehensive Cancer Center, 1600 Divisadero Street, Suite H1031, San Francisco, California 94143-1708 (United States); Department of Industrial Engineering and Operations Research and Department of Electrical Engineering and Computer Science, University of California, Berkeley, 4141 Etcheverry Hall, Berkeley, California 94720-1777 (United States)

    2011-07-15

    Purpose: Many planning methods for high dose rate (HDR) brachytherapy require an iterative approach. A set of computational parameters are hypothesized that will give a dose plan that meets dosimetric criteria. A dose plan is computed using these parameters, and if any dosimetric criteria are not met, the process is iterated until a suitable dose plan is found. In this way, the dose distribution is controlled by abstract parameters. The purpose of this study is to develop a new approach for HDR brachytherapy by directly optimizing the dose distribution based on dosimetric criteria. Methods: The authors developed inverse planning by integer program (IPIP), an optimization model for computing HDR brachytherapy dose plans and a fast heuristic for it. They used their heuristic to compute dose plans for 20 anonymized prostate cancer image data sets from patients previously treated at their clinic database. Dosimetry was evaluated and compared to dosimetric criteria. Results: Dose plans computed from IPIP satisfied all given dosimetric criteria for the target and healthy tissue after a single iteration. The average target coverage was 95%. The average computation time for IPIP was 30.1 s on an Intel(R) Core{sup TM}2 Duo CPU 1.67 GHz processor with 3 Gib RAM. Conclusions: IPIP is an HDR brachytherapy planning system that directly incorporates dosimetric criteria. The authors have demonstrated that IPIP has clinically acceptable performance for the prostate cases and dosimetric criteria used in this study, in both dosimetry and runtime. Further study is required to determine if IPIP performs well for a more general group of patients and dosimetric criteria, including other cancer sites such as GYN.

  7. Braquiterapia de alta taxa de dose associada a radioterapia externa no tratamento de angiossarcoma extenso do couro cabeludo: relato de caso Combination of high-dose rate brachytherapy and external beam radiotherapy for the treatment of advanced scalp angiosarcoma: case report

    Directory of Open Access Journals (Sweden)

    André Cavalcanti Gentil

    2001-10-01

    Full Text Available Os autores apresentam um caso de extenso angiossarcoma do couro cabeludo submetido a radioterapia exclusiva, pela associação de roentgenterapia de ortovoltagem e braquiterapia de alta taxa de dose utilizando um molde. Descrevem os aspectos clínicos, técnicos e a evolução terapêutica. Destacam as particularidades e a utilidade da braquiterapia de alta taxa de dose, nesta situação em particular, e fazem uma análise comparativa das dificuldades e limitações caso a braquiterapia de baixa taxa de dose fosse empregada. Concluem ser a braquiterapia de alta taxa de dose uma opção útil, prática e segura para as lesões neoplásicas superficiais do escalpe, podendo ser considerada uma alternativa ao tratamento com elétrons.The authors report a case of a patient with an extensive angiosarcoma of the scalp that was submitted only to radiotherapy with a combination of orthovoltage roentgentherapy and high-dose rate brachytherapy, using a mould. The clinical and technical features as well as the therapeutic outcome are presented, and the usefulness and peculiarities of high-dose rate brachytherapy for this particular indication is discussed. A comparative analysis of the difficulties and limitations of employing low-dose rate brachytherapy is also presented. The authors concluded that high-dose rate brachytherapy might be an useful, practical and safe option to treat neoplastic lesions of the scalp, and an alternative treatment to electrontherapy.

  8. The high dynamic range pixel array detector (HDR-PAD): Concept and design

    Energy Technology Data Exchange (ETDEWEB)

    Shanks, Katherine S.; Philipp, Hugh T.; Weiss, Joel T.; Becker, Julian; Tate, Mark W. [Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY 14853 (United States); Gruner, Sol M., E-mail: smg26@cornell.edu [Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY 14853 (United States); Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, NY 14853 (United States)

    2016-07-27

    Experiments at storage ring light sources as well as at next-generation light sources increasingly require detectors capable of high dynamic range operation, combining low-noise detection of single photons with large pixel well depth. XFEL sources in particular provide pulse intensities sufficiently high that a purely photon-counting approach is impractical. The High Dynamic Range Pixel Array Detector (HDR-PAD) project aims to provide a dynamic range extending from single-photon sensitivity to 10{sup 6} photons/pixel in a single XFEL pulse while maintaining the ability to tolerate a sustained flux of 10{sup 11} ph/s/pixel at a storage ring source. Achieving these goals involves the development of fast pixel front-end electronics as well as, in the XFEL case, leveraging the delayed charge collection due to plasma effects in the sensor. A first prototype of essential electronic components of the HDR-PAD readout ASIC, exploring different options for the pixel front-end, has been fabricated. Here, the HDR-PAD concept and preliminary design will be described.

  9. Characterization of HDR Ir-192 source for 3D planning system

    Energy Technology Data Exchange (ETDEWEB)

    Fonseca, Gabriel P.; Yoriyaz, Helio; Antunes, Paula C.G.; Siqueira, Paulo T.D., E-mail: gabriel.fonseca@usp.b, E-mail: hyoriyaz@ipen.b, E-mail: ptsiquei@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Rubo, Rodrigo [Universidade de Sao Paulo (HC/FMUSP), Sao Paulo, SP (Brazil). Hospital das Clinicas. Servico de Radioterapia; Minamisawa, Renato A., E-mail: renato.minamisawa@psi.c [Paul Scherrer Institut (PSI), Villigen (Switzerland); Ferreira, Louise A. [Universidade Estadual de Maringa (UEM), PR (Brazil). Fac. de Medicina

    2011-07-01

    Brachytherapy treatment involves surgical or cavitary insertion of radioactive sources for diseases treatments, such as: lung, gynecologic or prostate cancer. This technique has great ability to administer high doses to the tumor, with adjacent normal tissue preservation equal or better than external beam radiation therapy. Several innovations have been incorporated in this treatment technique, such as, 3D treatment planning system and computer guided sources. In detriment to scientific advances there are no protocols that relate dose with tumor volume, organs or A point, established by ICRU38 and used to prescribe dose in treatment planning system. Several international studies, like as EMBRACE, the multicentre international study, has been trying to correlate the dose volume using 3D planning systems and medical images, as those obtained by CT or MRI, to establish treatment protocols. With the objective of analyzing the 3D dose distribution, a micro Selectron-HDR remote afterloading device for high dose-rate (HDR) was characterized in the present work. Through the data provided by the manufacturer the source was simulated, using the MCNP5 code to calculate American Association of Physicists in Medicine Task Group No. 43 report (AAPM TG43) specified parameters. The simulations have shown great agreement when compared to the ONCENTRA planning system results and those provided by literature. The micro Selectron-HDR remote afterloading device will be utilized to simulate 3D dose distribution through CT images processed by an auxiliary software which process DICOM images. (author)

  10. Comparative Analysis between LDR and HDR Images for Automatic Fruit Recognition and Counting

    Directory of Open Access Journals (Sweden)

    Tatiana M. Pinho

    2017-01-01

    Full Text Available Precision agriculture is gaining an increasing interest in the current farming paradigm. This new production concept relies on the use of information technology (IT to provide a control and supervising structure that can lead to better management policies. In this framework, imaging techniques that provide visual information over the farming area play an important role in production status monitoring. As such, accurate representation of the gathered production images is a major concern, especially if those images are used in detection and classification tasks. Real scenes, observed in natural environment, present high dynamic ranges that cannot be represented by the common LDR (Low Dynamic Range devices. However, this issue can be handled by High Dynamic Range (HDR images since they have the ability to store luminance information similarly to the human visual system. In order to prove their advantage in image processing, a comparative analysis between LDR and HDR images, for fruits detection and counting, was carried out. The obtained results show that the use of HDR images improves the detection performance to more than 30% when compared to LDR.

  11. Advanced single-stream HDR coding using JVET JEM with backward compatibility options

    Science.gov (United States)

    Topiwala, Pankaj; Dai, Wei; Krishnan, Madhu

    2017-09-01

    This paper presents a state of the art approach in HDR/WCG video coding developed at FastVDO called FVHDR, and based on the JEM 6 Test Model of the Joint Exploration Team, a joint committee of ITU|ISO/IEC. A fully automatic adaptive video process that differs from a known HDR video processing chain (analogous to HDR10, herein called "anchor") developed recently in the standards committee JVET, is used. FVHDR works entirely within the framework of JEM software model, but adds additional tools. These tools can become an integral part of a future video coding standard, or be extracted as additional pre- and post-processing chains. Reconstructed video sequences using FVHDR show a subjective visual quality superior to the output of the anchor. Moreover the resultant SDR content generated by the data adaptive grading process is backward compatible. Representative objective results for the system include: results for DE100, and PSNRL100, were -13.4%, and -3.8% respectively.

  12. Comparing subjective and objective quality assessment of HDR images compressed with JPEG-XT

    DEFF Research Database (Denmark)

    Mantel, Claire; Ferchiu, Stefan Catalin; Forchhammer, Søren

    2014-01-01

    In this paper a subjective test in which participants evaluate the quality of JPEG-XT compressed HDR images is presented. Results show that for the selected test images and display, the subjective quality reached its saturation point starting around 3bpp. Objective evaluations are obtained by app...... the best performance with the limit that it does not capture the quality saturation. The usage of the gamma correction prior to applying metrics depends on the characteristics of each objective metric.......In this paper a subjective test in which participants evaluate the quality of JPEG-XT compressed HDR images is presented. Results show that for the selected test images and display, the subjective quality reached its saturation point starting around 3bpp. Objective evaluations are obtained...... by applying a model of the display and providing the modeled images to three objective metrics dedicated to HDR content. Objective grades are compared with subjective data both in physical domain and using a gamma correction to approximate perceptually uniform luminance coding. The MRSE metric obtains...

  13. The Ansel Adams zone system: HDR capture and range compression by chemical processing

    Science.gov (United States)

    McCann, John J.

    2010-02-01

    We tend to think of digital imaging and the tools of PhotoshopTM as a new phenomenon in imaging. We are also familiar with multiple-exposure HDR techniques intended to capture a wider range of scene information, than conventional film photography. We know about tone-scale adjustments to make better pictures. We tend to think of everyday, consumer, silver-halide photography as a fixed window of scene capture with a limited, standard range of response. This description of photography is certainly true, between 1950 and 2000, for instant films and negatives processed at the drugstore. These systems had fixed dynamic range and fixed tone-scale response to light. All pixels in the film have the same response to light, so the same light exposure from different pixels was rendered as the same film density. Ansel Adams, along with Fred Archer, formulated the Zone System, staring in 1940. It was earlier than the trillions of consumer photos in the second half of the 20th century, yet it was much more sophisticated than today's digital techniques. This talk will describe the chemical mechanisms of the zone system in the parlance of digital image processing. It will describe the Zone System's chemical techniques for image synthesis. It also discusses dodging and burning techniques to fit the HDR scene into the LDR print. Although current HDR imaging shares some of the Zone System's achievements, it usually does not achieve all of them.

  14. An experimental MOSFET approach to characterize (192)Ir HDR source anisotropy.

    Science.gov (United States)

    Toye, W C; Das, K R; Todd, S P; Kenny, M B; Franich, R D; Johnston, P N

    2007-09-07

    The dose anisotropy around a (192)Ir HDR source in a water phantom has been measured using MOSFETs as relative dosimeters. In addition, modeling using the EGSnrc code has been performed to provide a complete dose distribution consistent with the MOSFET measurements. Doses around the Nucletron 'classic' (192)Ir HDR source were measured for a range of radial distances from 5 to 30 mm within a 40 x 30 x 30 cm(3) water phantom, using a TN-RD-50 MOSFET dosimetry system with an active area of 0.2 mm by 0.2 mm. For each successive measurement a linear stepper capable of movement in intervals of 0.0125 mm re-positioned the MOSFET at the required radial distance, while a rotational stepper enabled angular displacement of the source at intervals of 0.9 degrees . The source-dosimeter arrangement within the water phantom was modeled using the standardized cylindrical geometry of the DOSRZnrc user code. In general, the measured relative anisotropy at each radial distance from 5 mm to 30 mm is in good agreement with the EGSnrc simulations, benchmark Monte Carlo simulation and TLD measurements where they exist. The experimental approach employing a MOSFET detection system of small size, high spatial resolution and fast read out capability allowed a practical approach to the determination of dose anisotropy around a HDR source.

  15. Prostate CT segmentation method based on nonrigid registration in ultrasound-guided CT-based HDR prostate brachytherapy

    Science.gov (United States)

    Yang, Xiaofeng; Rossi, Peter; Ogunleye, Tomi; Marcus, David M.; Jani, Ashesh B.; Mao, Hui; Curran, Walter J.; Liu, Tian

    2014-01-01

    Purpose: The technological advances in real-time ultrasound image guidance for high-dose-rate (HDR) prostate brachytherapy have placed this treatment modality at the forefront of innovation in cancer radiotherapy. Prostate HDR treatment often involves placing the HDR catheters (needles) into the prostate gland under the transrectal ultrasound (TRUS) guidance, then generating a radiation treatment plan based on CT prostate images, and subsequently delivering high dose of radiation through these catheters. The main challenge for this HDR procedure is to accurately segment the prostate volume in the CT images for the radiation treatment planning. In this study, the authors propose a novel approach that integrates the prostate volume from 3D TRUS images into the treatment planning CT images to provide an accurate prostate delineation for prostate HDR treatment. Methods: The authors’ approach requires acquisition of 3D TRUS prostate images in the operating room right after the HDR catheters are inserted, which takes 1–3 min. These TRUS images are used to create prostate contours. The HDR catheters are reconstructed from the intraoperative TRUS and postoperative CT images, and subsequently used as landmarks for the TRUS–CT image fusion. After TRUS–CT fusion, the TRUS-based prostate volume is deformed to the CT images for treatment planning. This method was first validated with a prostate-phantom study. In addition, a pilot study of ten patients undergoing HDR prostate brachytherapy was conducted to test its clinical feasibility. The accuracy of their approach was assessed through the locations of three implanted fiducial (gold) markers, as well as T2-weighted MR prostate images of patients. Results: For the phantom study, the target registration error (TRE) of gold-markers was 0.41 ± 0.11 mm. For the ten patients, the TRE of gold markers was 1.18 ± 0.26 mm; the prostate volume difference between the authors’ approach and the MRI-based volume was 7.28% ± 0

  16. Evaluation of Magnetic Resonance Imaging Safety and Imaging Issues Associated with the Occlusion Balloon Used during Fetoscopic Endoluminal Tracheal Occlusion.

    Science.gov (United States)

    Victoria, Teresa; Johnson, Ann M; Adzick, N Scott; Hedrick, Holly L; Shellock, Frank G

    2017-10-05

    Congenital diaphragmatic hernias can be successfully treated by fetoscopic tracheal occlusion (FETO), a minimally invasive procedure that may improve postnatal survival. The endoluminal balloon utilized for FETO contains a metallic component that may pose possible risks for the fetus and mother related to the use of magnetic resonance imaging (MRI). The objective of this study is to evaluate MRI-related imaging and safety issues (magnetic field interactions, heating, and artifacts) for the occlusion balloon used in FETO. Using well-established techniques, tests were performed to assess magnetic field interactions (translational attraction and torque) and MRI-related heating and artifacts that occurred when exposing the occlusion balloon typically used for FETO (Goldbal2, Balt, www.balt.fr) to a 3-T magnet. MRI-related heating was determined by placing the occlusion balloon in a gelled-saline-filled, head-torso phantom and conducting MRI at relatively high, whole-body-averaged specific absorption rate (2.9 W/kg) for 15 min. Artifacts were measured in association with the use of T1-weighted, spin-echo and gradient-echo pulse sequences. The balloon displayed minor magnetic field interactions and physiologically inconsequential heating (highest temperature rise: 0.1°C above background). Artifacts extended approximately 10 mm from the occlusion balloon on the gradient-echo pulse sequence, suggesting that anatomy located at a position greater than this distance may be visualized on MRI. In this paper, we demonstrate that the risks of performing MRI at 3 T or less in a patient who has this occlusion balloon in place are acceptable (or MR conditional, using current terminology). © 2017 S. Karger AG, Basel.

  17. SU-F-T-55: Reproducibility of Interstitial HDR Brachytherapy Plans

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S; Ellis, R; Traughber, B; Podder, T [University Hospitals Case Medical Center, Cleveland, OH (United States)

    2016-06-15

    Purpose: Treating gynecological cancers with interstitial high-dose-rate (HDR) brachytherapy requires precise reconstruction of catheter positions to obtain accurate dosimetric plans. In this study, we investigated the degree of reproducibility of dosimetric plans for Syed HDR brachytherapy. Methods: We randomly selected five patients having cervix-vaginal cancer who were recently treated in our clinic with interstitial HDR brachytherapy with a prescription dose of 25–30 Gy in five fractions. Interstitial needles/catheters were placed under fluoroscopic guidance and intra-operative 3T MRI scan was performed to confirm the desired catheter placement for adequate target volume coverage. A CT scan was performed and fused with the MRI for delineating high-risk CTV (HR-CTV), intermediate-risk CTV (IR-CTV) and OARs. HDR treatment plans were generated using Oncentra planning software. A single plan was used for all five fractions of treatment for each patient. For this study, we took the original clinical plan and removed all the reconstructed catheters from the plan keeping the original contours unchanged. Then, we manually reconstructed all the catheters and entered the same dwell time from the first original clinical plan. The dosimetric parameters studied were: D90 for HR-CTV and IR-CV, and D2cc for bladder, rectum, sigmoid and bowel. Results: The mean of absolute differences in dosimetric coverage (D90) were (range): 1.3% (1.0–2.0%) and 2.0% (0.9–3.6%) for HR-CTV and IR-CTV, respectively. In case of OARs, the mean of absolute variations in D2cc were (range): 4.7% (0.7–8.9%) for bladder, 1.60% (0.3–3.2%) for rectum, 1.6% (0–3.9%) for sigmoid, and 1.8% (0–5.1%) for bowel. Conclusion: Overall, the reproducibility of interstitial HDR plans was within clinically acceptable limit. Observed maximum variation in D2cc for bladder. If number of catchers and dwell points were relatively low or any one catheter was heavily loaded, then reproducibility of the plan

  18. Evaluation of water-mimicking solid phantom materials for use in HDR and LDR brachytherapy dosimetry

    Science.gov (United States)

    Schoenfeld, Andreas A.; Thieben, Maike; Harder, Dietrich; Poppe, Björn; Chofor, Ndimofor

    2017-12-01

    In modern HDR or LDR brachytherapy with photon emitters, fast checks of the dose profiles generated in water or a water-equivalent phantom have to be available in the interest of patient safety. However, the commercially available brachytherapy photon sources cover a wide range of photon emission spectra, and the range of the in-phantom photon spectrum is further widened by Compton scattering, so that the achievement of water-mimicking properties of such phantoms involves high requirements on their atomic composition. In order to classify the degree of water equivalence of the numerous commercially available solid water-mimicking phantom materials and the energy ranges of their applicability, the radial profiles of the absorbed dose to water, D w, have been calculated using Monte Carlo simulations in these materials and in water phantoms of the same dimensions. This study includes the HDR therapy sources Nucletron Flexisource Co-60 HDR (60Co), Eckert und Ziegler BEBIG GmbH CSM-11 (137Cs), Implant Sciences Corporation HDR Yb-169 Source 4140 (169Yb) as well as the LDR therapy sources IsoRay Inc. Proxcelan CS-1 (131Cs), IsoAid Advantage I-125 IAI-125A (125I), and IsoAid Advantage Pd-103 IAPd-103A (103Pd). Thereby our previous comparison between phantom materials and water surrounding a Varian GammaMed Plus HDR therapy 192Ir source (Schoenfeld et al 2015) has been complemented. Simulations were performed in cylindrical phantoms consisting of either water or the materials RW1, RW3, Solid Water, HE Solid Water, Virtual Water, Plastic Water DT, Plastic Water LR, Original Plastic Water (2015), Plastic Water (1995), Blue Water, polyethylene, polystyrene and PMMA. While for 192Ir, 137Cs and 60Co most phantom materials can be regarded as water equivalent, for 169Yb the materials Plastic Water LR, Plastic Water DT and RW1 appear as water equivalent. For the low-energy sources 106Pd, 131Cs and 125I, only Plastic Water LR can be classified as water equivalent.

  19. High dynamic range adaptive real-time smart camera: an overview of the HDR-ARTiST project

    Science.gov (United States)

    Lapray, Pierre-Jean; Heyrman, Barthélémy; Ginhac, Dominique

    2015-04-01

    Standard cameras capture only a fraction of the information that is visible to the human visual system. This is specifically true for natural scenes including areas of low and high illumination due to transitions between sunlit and shaded areas. When capturing such a scene, many cameras are unable to store the full Dynamic Range (DR) resulting in low quality video where details are concealed in shadows or washed out by sunlight. The imaging technique that can overcome this problem is called HDR (High Dynamic Range) imaging. This paper describes a complete smart camera built around a standard off-the-shelf LDR (Low Dynamic Range) sensor and a Virtex-6 FPGA board. This smart camera called HDR-ARtiSt (High Dynamic Range Adaptive Real-time Smart camera) is able to produce a real-time HDR live video color stream by recording and combining multiple acquisitions of the same scene while varying the exposure time. This technique appears as one of the most appropriate and cheapest solution to enhance the dynamic range of real-life environments. HDR-ARtiSt embeds real-time multiple captures, HDR processing, data display and transfer of a HDR color video for a full sensor resolution (1280 1024 pixels) at 60 frames per second. The main contributions of this work are: (1) Multiple Exposure Control (MEC) dedicated to the smart image capture with alternating three exposure times that are dynamically evaluated from frame to frame, (2) Multi-streaming Memory Management Unit (MMMU) dedicated to the memory read/write operations of the three parallel video streams, corresponding to the different exposure times, (3) HRD creating by combining the video streams using a specific hardware version of the Devebecs technique, and (4) Global Tone Mapping (GTM) of the HDR scene for display on a standard LCD monitor.

  20. A New Occlusion Device: Application of the ArtVentive Endoluminal Occlusion System (EOS)—First in Human Clinical Trial

    Energy Technology Data Exchange (ETDEWEB)

    Venbrux, Anthony C., E-mail: avenbrux@mfa.gwu.edu [The George Washington University Medical Center, Division of Vascular and Interventional Radiology (United States); Rudakov, Leon, E-mail: leonrudakov@artventivemedical.com [Artventive Medical Group, Inc. (United States); Plass, Andre, E-mail: andre.plass@usz.ch; Emmert, Maximilian Y., E-mail: maximilian.emmert@usz.ch [University Hospital Zurich, Clinic for Cardiac and Vascular Surgery (Switzerland); Ebner, Adrian, E-mail: adrianebner@fundacor.com.py [Sanatorio Privado Santa Clara, Cath Lab Department (Paraguay)

    2013-05-24

    PurposeThe purpose of this study was to determine the safety and efficacy of a new endoluminal occlusion device, ArtVentive endoluminal occlusion system (EOS), to occlude the spermatic vein in symptomatic males with varicoceles.MethodsThe ArtVentive EOS device has been developed for percutaneous, peripheral occlusion of the peripheral arterial and venous vasculature. The system is comprised of an implantable occlusion device and a delivery catheter. At present, there are two device sizes: (a) size 1 for target vessels ranging between 3.5 and 5.5 mm in diameter, and (b) size 2 for target vessels 5.5–8.5 mm in diameter. The treatment group included six adult males, ages 22–34 years. Nine target vessels were occluded. A total of 20 devices were implanted in six subjects.ResultsThe acute occlusion rate at the end of the procedure was 100 % occurring in nine of nine vessels. The spermatic veins of all patients remained occluded on venography at 30 days follow-up. Pain scores related to varicoceles decreased in five of six patients.ConclusionsAlthough we recognize this study is limited, initial experience indicates that the ArtVentive EOS is a safe and effective new device for occlusion of vessels (varicoceles). The device has potential applications in other clinical conditions requiring occlusion of veins or arteries.

  1. Palliative interstitial HDR brachytherapy for recurrent rectal cancer. Implantation techniques and results

    Energy Technology Data Exchange (ETDEWEB)

    Kolotas, C. [Dept. of Radiation Oncology, Offenbach Hospital, Offenbach (Germany); Dept. of Radio-Oncology, Univ. of Bern, Inselspital, Bern (Switzerland); Roeddiger, S.; Martin, T.; Tselis, N.; Baltas, D.; Zamboglou, N. [Dept. of Radiation Oncology, Offenbach Hospital, Offenbach (Germany); Strassmann, G. [Dept. of Radiotherapy, Univ. Hospital, Philipps Univ., Marburg (Germany); Aebersold, D.M. [Dept. of Radio-Oncology, Univ. of Bern, Inselspital, Bern (Switzerland)

    2003-07-01

    Purpose: To report the methods and clinical results of CT-based interstitial high-dose-rate (HDR) brachytherapy procedures for the palliative treatment of recurrent rectal cancer. Patients and Methods: A total of 44 brachytherapy implants were performed in 38 patients. CT-guided catheter implants were performed in 34 patients under local anesthesia and sedation, and four patients were implanted intraoperatively. Of 40 CT-guided implants, 20 were done using metallic needles introduced via the sacrum and 20 were transperineal implants of plastic tubes in the presacral region. Postimplant CT scans were used for three-dimensional (3-D) conformal brachytherapy planning. Patients implanted with metallic needles were given a single fraction of 10-15 Gy using HDR {sup 192}Ir, and those who received transperineal implants of plastic catheters were given fractionated brachytherapy, 5 Gy twice daily to a total dose of 30-40 Gy. The median tumor volume was 225 cm{sup 3} with a range of 41-2,103 cm{sup 3}. Results: After a median follow-up of 23.4 months, a total of 13/38 patients were alive. The median postbrachytherapy survival was 15 months with 18 of the 25 deaths due to distant metastases. Tumor response was as follows: 6/38 partial remission, 28/38 stable disease, and 4/38 local progression. A planning target volume (PTV) coverage > 85% was achieved in 42/44 implants. The treatment was well tolerated, and no acute complications were observed. One patient developed a fistula after 8 months. Pain relief was recorded in 34 patients (89.5%), and the median duration of this palliative effect was 5 months with a range of 1-13 months. Conclusions: Interstitial HDR brachytherapy is a valuable tool for the delivery of high doses and achieves effective palliation in recurrent rectal carcinoma. (orig.)

  2. SU-F-T-63: Dosimetric Relevance of the Valencia and Leipzig HDR Applicators Plastic Cap

    Energy Technology Data Exchange (ETDEWEB)

    Granero, D [ERESA-Hospital General Universitario, Valencia (Spain); Candela-Juan, C [National Dosimetry Centre (CND), Valencia (Spain); Vijande, J; Ballester, F [University of Valencia, Burjassot (Spain); Perez-Calatayud, J [Hospital La Fe, Valencia (Spain); Jacob, D; Mourtada, F [Helen F. Graham Cancer Center, Christiana Care Health System, Newark, DE (United States)

    2016-06-15

    Purpose: Utilization of HDR brachytherapy treatment of skin lesions using collimated applicators, such as the Valencia or Leipzig is increasing. These applicators are made of cup-shaped tungsten material in order to focalize the radiation into the lesion and to protect nearby tissues. These applicators have an attachable plastic cap that removes secondary electrons generated in the applicator and flattens the treatment surface. The purpose of this study is to examine the dosimetric impact of this cap, and the effect if the cap is not placed during the HDR fraction delivery. Methods: Monte Carlo simulations have been done using the code Geant4 for the Valencia and Leipzig applicators. Dose rate distributions have been obtained for the applicators with and without the plastic cap. An experimental study using EBT3 radiochromic film has been realized in order to verify the Monte Carlo results. Results: The Monte Carlo simulations show that absorbed dose in the first millimeter of skin can increase up to 180% for the Valencia applicator if the plastic cap is absent and up to 1500% for the Leipzig applicators. At deeper distances the increase of dose is smaller being about 10–15%. Conclusion: Important differences have been found if the plastic cap of the applicators is absent in the treatment producing an overdosage in the skin. The user should have a checklist to remind him check always before HDR fraction delivery to insure the plastic cap is placed on the applicator. This work was supported in part by Generalitat Valenciana under Project PROMETEOII/2013/010, by the Spanish Government under Project No. FIS2013-42156, and by a research agreement with Elekta Brachytherapy, Veenendaal, The Netherlands.

  3. Dosimetry evaluation of SAVI-based HDR brachytherapy for partial breast irradiation

    Directory of Open Access Journals (Sweden)

    Manoharan Sivasubramanian

    2010-01-01

    Full Text Available Accelerated partial breast irradiation (APBI with high dose rate (HDR brachytherapy offers an excellent compact course of radiation due to its limited number of fractions for early-stage carcinoma of breast. One of the recent devices is SAVI (strut-adjusted volume implant, which has 6, 8 or 10 peripheral source channels with one center channel. Each channel can be differentially loaded. This paper focuses on the treatment planning, dosimetry and quality assurance aspects of HDR brachytherapy implant with GammaMed Plus HDR afterloader unit. The accelerated PBI balloon devices normally inflate above 35 cc range, and hence these balloon type devices cannot be accommodated in small lumpectomy cavity sizes. CT images were obtained and 3-D dosimetric plans were done with Brachyvision planning system. The 3-D treatment planning and dosimetric data were evaluated with planning target volume (PTV_eval V90, V95, V150, V200 skin dose and minimum distance to skin. With the use of the SAVI 6-1 mini device, we were able to accomplish an excellent coverage - V90, V95, V150 and V200 to 98%, 95%, 37 cc (<50 cc volume and 16 cc (<20 cc volume, respectively. Maximum skin dose was between 73% and 90%, much below the prescribed dose of 34 Gy. The minimum skin distance achieved was 5 to 11 mm. The volume that received 50% of the prescribed radiation dose was found to be lower with SAVI. The multi-channel SAVI-based implants reduced the maximum skin dose to markedly lower levels as compared to other modalities, simultaneously achieving best dose coverage to target volume. Differential-source dwell-loading allows modulation of the radiation dose distribution in symmetric or asymmetric opening of the catheter shapes and is also advantageous in cavities close to chest wall.

  4. SU-E-T-169: Characterization of Pacemaker/ICD Dose in SAVI HDR Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Kalavagunta, C; Lasio, G; Yi, B; Zhou, J; Lin, M [Univ. of Maryland School Of Medicine, Baltimore, MD (United States)

    2015-06-15

    Purpose: It is important to estimate dose to pacemaker (PM)/Implantable Cardioverter Defibrillator (ICD) before undertaking Accelerated Partial Breast Treatment using High Dose Rate (HDR) brachytherapy. Kim et al. have reported HDR PM/ICD dose using a single-source balloon applicator. To the authors knowledge, there have so far not been any published PM/ICD dosimetry literature for the Strut Adjusted Volume Implant (SAVI, Cianna Medical, Aliso Viejo, CA). This study aims to fill this gap by generating a dose look up table (LUT) to predict maximum dose to the PM/ICD in SAVI HDR brachytherapy. Methods: CT scans for 3D dosimetric planning were acquired for four SAVI applicators (6−1-mini, 6−1, 8−1 and 10−1) expanded to their maximum diameter in air. The CT datasets were imported into the Elekta Oncentra TPS for planning and each applicator was digitized in a multiplanar reconstruction window. A dose of 340 cGy was prescribed to the surface of a 1 cm expansion of the SAVI applicator cavity. Cartesian coordinates of the digitized applicator were determined in the treatment leading to the generation of a dose distribution and corresponding distance-dose prediction look up table (LUT) for distances from 2 to 15 cm (6-mini) and 2 to 20 cm (10–1).The deviation between the LUT doses and the dose to the cardiac device in a clinical case was evaluated. Results: Distance-dose look up table were compared to clinical SAVI plan and the discrepancy between the max dose predicted by the LUT and the clinical plan was found to be in the range (−0.44%, 0.74%) of the prescription dose. Conclusion: The distance-dose look up tables for SAVI applicators can be used to estimate the maximum dose to the ICD/PM, with a potential usefulness for quick assessment of dose to the cardiac device prior to applicator placement.

  5. Psychological repercussions related to brachytherapy treatment in women with gynecological cancer: analysis of production from 1987 to 2007 Repercusiones psicológicas relacionadas al tratamiento de braquiterapia en mujeres con cáncer ginecológico: un análisis de la producción de 1987 a 2007 Repercussões psicológicas relacionadas ao tratamento de braquiterapia em mulheres com câncer ginecológico: análise da produção de 1987 a 2007

    Directory of Open Access Journals (Sweden)

    Gisele Curi de Barros

    2008-12-01

    Full Text Available One of the radiotherapeutic modalities for gynecological cancer treatment is brachytherapy, characterized by the placement of radioactive materials near the tumor. This treatment can bring side effects for patients. Due to the emotional issues involved, the objective of this research was to apprehend studies about psychological repercussions related to brachytherapy treatment in women with gynecological cancer, through a literature review. The results revealed an embryionic production, with only one study produced in Brazil. A higher concentration of studies was found in the Nursing area. Research focused on psychosocial repercussions, attempting to understand the patients' experiences before, during and after treatment, evidencing physical and psychological consequences that affect their quality of life. It is important to consider the expansion of this production through psychological research that furthers the comprehension about the experience of women submitted to brachytherapy.Una de las modalidades de radioterapia para el tratamiento del cáncer ginecológico es la braquiterapia, caracterizada por la colocación de materiales radioactivos junto al tumor. Esta terapéutica puede traer efectos colaterales a los pacientes. Pensando en las cuestiones emocionales, este trabajo tuvo como objetivo, a través de la revisión de la literatura, revisar los estudios que se refiriesen a las repercusiones psicológicas relacionadas al tratamiento de braquiterapia en mujeres con cáncer ginecológico. Los resultados revelaron una producción embrionaria, con apenas un trabajo producido en Brasil. Hubo una mayor concentración de estudios en el área de Enfermería. Los trabajos se centraron en las repercusiones psicosociales, buscando comprender la experiencia de las pacientes antes, durante, y después del término de la aplicación del tratamiento, lo que colocó en evidencia consecuencias físicas y psicológicas que afectan la calidad de vida. Es

  6. Robust Estimation of HDR in fMRI using H-infinity Filters

    DEFF Research Database (Denmark)

    Puthusserypady, Sadasivan; Jue, R.; Ratnarajah, T.

    2010-01-01

    . The H8 approach is used because it safeguards against the worst case disturbances and makes no assumptions on the (statistical) nature of the signals [B. Hassibi and T. Kailath, in Proc. ICASSP, 1995, vol. 2, pp. 949-952; T. Ratnarajah and S. Puthusserypady, in Proc. 8th IEEEWorkshopDSP, 1998, pp. 1483......-1487]. Performances of the proposed techniques are compared to the conventional t-test method as well as the well-known LMSs and recursive least squares algorithms. Extensive numerical simulations show that the proposed methods result in better HDR estimations and activation detections....

  7. Salvage prostate HDR brachytherapy combined with interstitial hyperthermia for local recurrence after radiation therapy failure

    Energy Technology Data Exchange (ETDEWEB)

    Kukielka, A.M.; Hetnal, M.; Dabrowski, T.; Walasek, T.; Brandys, P.; Reinfuss, M. [Centre of Oncology, M. Sklodowska - Curie Institute, Krakow Branch, Department of Radiotherapy, Krakow (Poland); Nahajowski, D.; Kudzia, R.; Dybek, D. [Centre of Oncology, M. Sklodowska - Curie Institute, Krakow Branch, Department of Medical Physics, Department of Radiotherapy, Krakow (Poland)

    2014-02-15

    The aim of the present retrospective study is to evaluate toxicity and early clinical outcomes of interstitial hyperthermia (IHT) combined with high-dose rate (HDR) brachytherapy as a salvage treatment in patients with biopsy-confirmed local recurrence of prostate cancer after previous external beam radiotherapy. Between September 2008 and March 2013, 25 patients with local recurrence of previously irradiated prostate cancer were treated. The main eligibility criteria for salvage prostate HDR brachytherapy combined with interstitial hyperthermia were biopsy confirmed local recurrence and absence of nodal and distant metastases. All patients were treated with a dose of 30 Gy in 3 fractions at 21-day intervals. We performed 62 hyperthermia procedures out of 75 planned (83 %). The aim of the hyperthermia treatment was to heat the prostate to 41-43 C for 60 min. Toxicity for the organs of the genitourinary system and rectum was assessed according to the Common Terminology Criteria for Adverse Events (CTCAE, v. 4.03). Determination of subsequent biochemical failure was based on the Phoenix definition (nadir + 2 ng/ml). The median age was 71 years (range 62-83 years), the median initial PSA level was 16.3 ng/ml (range 6.37-64 ng/ml), and the median salvage PSA level was 2.8 ng/ml (1.044-25.346 ng/ml). The median follow-up was 13 months (range 4-48 months). The combination of HDR brachytherapy and IHT was well tolerated. The most frequent complications were nocturia, weak urine stream, urinary frequency, hematuria, and urgency. Grade 2 rectal hemorrhage was observed in 1 patient. No grade 3 or higher complications were observed. The 2-year Kaplan-Meier estimate of biochemical control after salvage treatment was 74 %. The PSA in 20 patients decreased below the presalvage level, while 11 patients achieved a PSA nadir < 0.5 ng/ml. All patients are still alive. Of the 7 patients who experienced biochemical failure, bone metastases were found in 2 patients. IHT in combination

  8. Monte Carlo and experimental dosimetric study of the mHDR-v2 brachytherapy source

    Directory of Open Access Journals (Sweden)

    Chandola Rakesh

    2010-01-01

    Full Text Available The conventional treatment planning system (TPS gives analytical calculations with ± 15 to 20% dose, which may lead to over exposure of critical organs or under dose of target. It is to obtain dose distribution parameters of nucletron high dose rate (HDR microselectron v2 (mHDR-v2 192 Ir brachytherapy source by experiment and by calculated study using Monte Carlo (MC EGSnrc code, and to find the similarity between them, and with any past study. To validate data, another MC GEANT4 study done in this work on the same source is also presented. Different software of the computer e.g. paint, excel, etc are employed for preparation of figures and graphs. The measured study of the source was done using an in-air ionization chamber, water phantom, and measurement set-up, while the calculated study was done by modeling the set up of the measured study by using the MC EGSnrc and GEANT4. Mean and probability are used in calculation of average values, and calculation of the uncertainties in result and discussion. The measured and calculated values of dose rate constant, radial dose function, and 2D anisotropy function were found to be in agreement with each other as well as with published data. The results of this study can be used as input to TPS.

  9. Quality control of the breast cancer treatments on Hdr brachytherapy with TLD-100

    Energy Technology Data Exchange (ETDEWEB)

    Torres H, F. [Universidad de Cordoba, Materials and Applied Physics Group, 230002 Monteria, Cordoba (Colombia); De la Espriella V, N. [Universidad de Cordoba, Grupo Avanzado de Materiales y Sistemas Complejos, 230002 Monteria, Cordoba (Colombia); Sanchez C, A., E-mail: franciscotorreshoyos@yahoo.com [Universidad de Cordoba, Departamento de Enfermeria, 230002 Monteria, Cordoba (Colombia)

    2014-07-01

    An anthropomorphic Phantom, a female trunk, was built with a natural bone structure and experimental material coated, glycerin and water-based material called JJT to build soft tissue equivalent to the muscle of human tissue, and a polymer (styrofoam) to build the lung as critical organ to simulate the treatment of breast cancer, with high dose rate brachytherapy (Hdr) and sources of Ir-192. The treatments were planned and calculated for the critical organ: Lung, and injury of 2 cm in diameter in breast with Micro Selectron Hdr system and the software Plato Brachytherapy V 14.1 of the Nucletron (Netherlands) which uses the standard protocol of radiotherapy for brachytherapy treatments. The dose experimentally measured with dosimeters TLD-100 LiF: Mg; Ti, which were previously calibrated, were placed in the same positions and bodies mentioned above, with less than 5% uncertainty. The reading dosimeters was carried out in a Harshaw TLD 4500. The results obtained for calculated treatments, using the standard simulator, and the experimental with TLD-100, show a high concordance, as they are on average a ± 1.1% making process becomes in a quality control of this type of treatments. (Author)

  10. Artist's colour rendering of HDR scenes in 3D Mondrian colour-constancy experiments

    Science.gov (United States)

    Parraman, Carinna E.; McCann, John J.; Rizzi, Alessandro

    2010-01-01

    The presentation provides an update on ongoing research using three-dimensional Colour Mondrians. Two still life arrangements comprising hand-painted coloured blocks of 11 different colours were subjected to two different lighting conditions of a nearly uniform light and directed spotlights. The three-dimensional nature of these test targets adds shadows and multiple reflections, not found in flat Mondrian targets. Working from exactly the same pair of scenes, an author painted them using watercolour inks and paints to recreate both LDR and HDR Mondrians on paper. This provided us with a second set of appearance measurements of both scenes. Here we measured appearances by measuring reflectances of the artist's rendering. Land's Colour Mondrian extended colour constancy from a pixel to a complex scene. Since it used a planar array in uniform illumination, it did not measure the appearances of real life 3-D scenes in non-uniform illumination. The experiments in this paper, by simultaneously studying LDR and HDR renditions of the same array of reflectances, extend Land's Mondrian towards real scenes in non-uniform illumination. The results show that the appearances of many areas in complex scenes do not correlate with reflectance.

  11. Interactive, multi-modality image registrations for combined MRI/MRSI-planned HDR prostate brachytherapy

    Directory of Open Access Journals (Sweden)

    Galen Reed

    2011-03-01

    Full Text Available Purpose: This study presents the steps and criteria involved in the series of image registrations used clinically during the planning and dose delivery of focal high dose-rate (HDR brachytherapy of the prostate. Material and methods: Three imaging modalities – Magnetic Resonance Imaging (MRI, Magnetic Resonance Spectroscopic Imaging (MRSI, and Computed Tomography (CT – were used at different steps during the process. MRSI is used for identification of dominant intraprosatic lesions (DIL. A series of rigid and nonrigid transformations were applied to the data to correct for endorectal-coil-induced deformations and for alignment with the planning CT. Mutual information was calculated as a morphing metric. An inverse planning optimization algorithm was applied to boost dose to the DIL while providing protection to the urethra, penile bulb, rectum, and bladder. Six prostate cancer patients were treated using this protocol. Results: The morphing algorithm successfully modeled the probe-induced prostatic distortion. Mutual information calculated between the morphed images and images acquired without the endorectal probe showed a significant (p = 0.0071 increase to that calculated between the unmorphed images and images acquired without the endorectal probe. Both mutual information and visual inspection serve as effective diagnostics of image morphing. The entire procedure adds less than thirty minutes to the treatment planning. Conclusion: This work demonstrates the utility of image transformations and registrations to HDR brachytherapy of prostate cancer.

  12. A study on the dose distributions in various materials from an Ir-192 HDR brachytherapy source.

    Directory of Open Access Journals (Sweden)

    Shih-Ming Hsu

    Full Text Available Dose distributions of (192Ir HDR brachytherapy in phantoms simulating water, bone, lung tissue, water-lung and bone-lung interfaces using the Monte Carlo codes EGS4, FLUKA and MCNP4C are reported. Experiments were designed to gather point dose measurements to verify the Monte Carlo results using Gafchromic film, radiophotoluminescent glass dosimeter, solid water, bone, and lung phantom. The results for radial dose functions and anisotropy functions in solid water phantom were consistent with previously reported data (Williamson and Li. The radial dose functions in bone were affected more by depth than those in water. Dose differences between homogeneous solid water phantoms and solid water-lung interfaces ranged from 0.6% to 14.4%. The range between homogeneous bone phantoms and bone-lung interfaces was 4.1% to 15.7%. These results support the understanding in dose distribution differences in water, bone, lung, and their interfaces. Our conclusion is that clinical parameters did not provide dose calculation accuracy for different materials, thus suggesting that dose calculation of HDR treatment planning systems should take into account material density to improve overall treatment quality.

  13. Study of the effect of usual heterogeneities in brachytherapy using Monte Carlo simulation; Estudio del efecto de heterogeneidades usuales en braquiterapia mediante simulacion Monte Carlo

    Energy Technology Data Exchange (ETDEWEB)

    Vera Sanchez, J. A.; Ruiz Morales, C.; Tobarra Gonzalez, B. M.

    2013-07-01

    The majority of current planning in brachytherapy systems don't count the composition of materials they form applicators, or the characteristics of the main interfaces present in the treatments. The objective of this study It is to compare the dosimetry distributions obtained by Monte Carlo simulations in geometric mannequins that they represent general features of the treatments that we find in our clinical practice, with results calculated according to the TG-43 formalism based on the existing consensus data for Ir-192 mHDR-v2 source. (Author)

  14. Implementation of the technique of partial irradiation accelerated the breast with high doses (HDR) brachytherapy; Puesta en marcha de la tecnica de irradiacion parcial acelerada de la mama con braquterapia de alta tasa de dosis (HDR)

    Energy Technology Data Exchange (ETDEWEB)

    Molina Lopez, M. Y.; Pardo Perez, E.; Castro Novais, J.; Martinez Ortega, J.; Ruiz Maqueda, S.; Cerro Penalver, E. del

    2013-07-01

    The objective of this work is presents procedure carried out in our Centre for the implementation of the accelerated partial breast irradiation (APBI, accelerated partial-breast irradiation) with high-rate brachytherapy (HDR), using plastic tubes as applicators. Carried out measures, the evaluation of the dosimetric parameters analyzing and presenting the results. (Author)

  15. A study of optimization techniques in HDR brachytherapy for the prostate

    Science.gov (United States)

    Pokharel, Ghana Shyam

    Several studies carried out thus far are in favor of dose escalation to the prostate gland to have better local control of the disease. But optimal way of delivery of higher doses of radiation therapy to the prostate without hurting neighboring critical structures is still debatable. In this study, we proposed that real time high dose rate (HDR) brachytherapy with highly efficient and effective optimization could be an alternative means of precise delivery of such higher doses. This approach of delivery eliminates the critical issues such as treatment setup uncertainties and target localization as in external beam radiation therapy. Likewise, dosimetry in HDR brachytherapy is not influenced by organ edema and potential source migration as in permanent interstitial implants. Moreover, the recent report of radiobiological parameters further strengthen the argument of using hypofractionated HDR brachytherapy for the management of prostate cancer. Firstly, we studied the essential features and requirements of real time HDR brachytherapy treatment planning system. Automating catheter reconstruction with fast editing tools, fast yet accurate dose engine, robust and fast optimization and evaluation engine are some of the essential requirements for such procedures. Moreover, in most of the cases we performed, treatment plan optimization took significant amount of time of overall procedure. So, making treatment plan optimization automatic or semi-automatic with sufficient speed and accuracy was the goal of the remaining part of the project. Secondly, we studied the role of optimization function and constraints in overall quality of optimized plan. We have studied the gradient based deterministic algorithm with dose volume histogram (DVH) and more conventional variance based objective functions for optimization. In this optimization strategy, the relative weight of particular objective in aggregate objective function signifies its importance with respect to other objectives

  16. Comparison of a unidirectional panoramic 3D endoluminal interpretation technique to traditional 2D and bidirectional 3D interpretation techniques at CT colonography: preliminary observations

    Energy Technology Data Exchange (ETDEWEB)

    Lenhart, D.K.; Babb, J.; Bonavita, J.; Kim, D. [Department of Radiology, NYU Medical Center, 560 First Avenue, Suite HW-202, New York, NY 10016 (United States); Bini, E.J. [Department of Medicine, NYU School of Medicine, NYU Medical Center, 560 First Avenue, Suite HW-202, New York, NY 10016 (United States); Megibow, A.J. [Department of Radiology, NYU Medical Center, 560 First Avenue, Suite HW-202, New York, NY 10016 (United States); Macari, M., E-mail: michael.macari@med.nyu.ed [Department of Radiology, NYU Medical Center, 560 First Avenue, Suite HW-202, New York, NY 10016 (United States)

    2010-02-15

    Aim: To compare the evaluation times and accuracy of unidirectional panoramic three-dimensional (3D) endoluminal interpretation to traditional two-dimensional (2D) and bidirectional 3D endoluminal techniques. materials and methods: Sixty-nine patients underwent computed tomography colonography (CTC) after bowel cleansing. Forty-five had no polyps and 24 had at least one polyp >=6 mm. Patients underwent same-day colonoscopy with segmental unblinding. Three experienced abdominal radiologists evaluated the data using one of three primary interpretation techniques: (1) 2D; (2) bidirectional 3D; (3) panoramic 3D. Mixed model analysis of variance and logistic regression for correlated data were used to compare techniques with respect to time and sensitivity and specificity. Results: Mean evaluation times were 8.6, 14.6, and 12.1 min, for 2D, 3D, and panoramic, respectively. 2D was faster than either 3D technique (p < 0.0001), and the panoramic technique was faster than bidirectional 3D (p = 0.0139). The overall sensitivity of each technique per polyp and per patient was 68.4 and 76.7% for 2D, 78.9 and 93.3% for 3D; and 78.9 and 86.7% for panoramic 3D. Conclusion: 2D interpretation was the fastest overall, the panoramic technique was significantly faster than the bidirectional with similar sensitivity and specificity. The sensitivity for a single reader was significantly lower using the 2D technique. Each reader should select the technique with which they are most successful.

  17. Balloon-based adjuvant radiotherapy in breast cancer: comparison between (99m)Tc and HDR (192)Ir.

    Science.gov (United States)

    de Campos, Tarcísio Passos Ribeiro; de Lima, Carla Flavia; Cuperschmid, Ethel Mizrahy

    2016-01-01

    To perform a comparative dosimetric analysis, based on computer simulations, of temporary balloon implants with (99m)Tc and balloon brachytherapy with high-dose-rate (HDR) (192)Ir, as boosts to radiotherapy. We hypothesized that the two techniques would produce equivalent doses under pre-established conditions of activity and exposure time. Simulations of implants with (99m)Tc-filled and HDR (192)Ir-filled balloons were performed with the Siscodes/MCNP5, modeling in voxels a magnetic resonance imaging set related to a young female. Spatial dose rate distributions were determined. In the dosimetric analysis of the protocols, the exposure time and the level of activity required were specified. The (99m)Tc balloon presented a weighted dose rate in the tumor bed of 0.428 cGy.h(-1).mCi(-1) and 0.190 cGyh(-1).mCi(-1) at the balloon surface and at 8-10 mm from the surface, respectively, compared with 0.499 and 0.150 cGyh(-1).mCi(-1), respectively, for the HDR (192)Ir balloon. An exposure time of 24 hours was required for the (99m)Tc balloon to produce a boost of 10.14 Gy with 1.0 Ci, whereas only 24 minutes with 10.0 Ci segments were required for the HDR (192)Ir balloon to produce a boost of 5.14 Gy at the same reference point, or 10.28 Gy in two 24-minutes fractions. Temporary (99m)Tc balloon implantation is an attractive option for adjuvant radiotherapy in breast cancer, because of its availability, economic viability, and similar dosimetry in comparison with the use of HDR (192)Ir balloon implantation, which is the current standard in clinical practice.

  18. Balloon-based adjuvant radiotherapy in breast cancer: comparison between {sup 99m}Tc and HDR {sup 192}Ir

    Energy Technology Data Exchange (ETDEWEB)

    Campos, Tarcisio Passos Ribeiro de; Lima, Carla Flavia de; Cuperschmid, Ethel Mizrahy, E-mail: tprcampos@pq.cnpq.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil)

    2016-03-15

    Objective: To perform a comparative dosimetric analysis, based on computer simulations, of temporary balloon implants with {sup 99m}Tc and balloon brachytherapy with high-dose-rate (HDR) {sup 192}Ir, as boosts to radiotherapy. We hypothesized that the two techniques would produce equivalent doses under pre-established conditions of activity and exposure time. Materials and methods: simulations of implants with {sup 99m}Tc-filled and HDR {sup 192}Ir-filled balloons were performed with the Siscodes/MCNP5, modeling in voxels a magnetic resonance imaging set related to a young female. Spatial dose rate distributions were determined. In the dosimetric analysis of the protocols, the exposure time and the level of activity required were specified. Results: the {sup 99m}Tc balloon presented a weighted dose rate in the tumor bed of 0.428 cGy.h{sup -1}.mCi{sup -1} and 0.190 cGyh{sup -1} at the balloon surface and at 8-10 mm from the surface, respectively, compared with 0.499 and 0.150 cGyh{sup -1}.mCi{sup -1}, respectively, for the HDR {sup 192}Ir balloon. An exposure time of 24 hours was required for the {sup 99m}Tc balloon to produce a boost of 10.14 Gy with 1.0 Ci, whereas only 24 minutes with 10.0 Ci segments were required for the HDR {sup 192}Ir balloon to produce a boost of 5.14 Gy at the same reference point, or 10.28 Gy in two 24-minutes fractions. Conclusion: temporary {sup 99m}Tc balloon implantation is an attractive option for adjuvant radiotherapy in breast cancer, because of its availability, economic viability, and similar dosimetry in comparison with the use of HDR {sup 192}Ir balloon implantation, which is the current standard in clinical practice. (author)

  19. Correction factors for source strength determination in HDR brachytherapy using the in-phantom method.

    Science.gov (United States)

    Ubrich, Frank; Wulff, Jörg; Engenhart-Cabillic, Rita; Zink, Klemens

    2014-05-01

    For the purpose of clinical source strength determination for HDR brachytherapy sources, the German society for Medical Physics (DGMP) recommends in their report 13 the usage of a solid state phantom (Krieger-phantom) with a thimble ionization chamber. In this work, the calibration chain for the determination of the reference air-kerma rate Ka,100 and reference dose rate to waterDw,1 by ionization chamber measurement in the Krieger-phantom was modeled via Monte Carlo simulations. These calculations were used to determine global correction factors k(tot), which allows a user to directly convert the reading of an ionization chamber calibrated in terms of absorbed dose to water, into the desired quantity Ka,100 or Dw,1. The factor k(tot) was determined for four available (192)Ir sources and one (60)Co source with three different thimble ionization chambers. Finally, ionization chamber measurements on three μSelectron V2 HDR sources within the Krieger-phantom were performed and Ka,100 was determined according to three different methods: 1) using a calibration factor in terms of absorbed dose to water with the global correction factor [Formula: see text] according DGMP 13 2) using a global correction factor calculated via Monte Carlo 3) using a direct reference air-kerma rate calibration factor determined by the national metrology institute PTB. The comparison of Monte Carlo based [Formula: see text] with those from DGMP 13 showed that the DGMP data were systematically smaller by about 2-2.5%. The experimentally determined [Formula: see text] , based on the direct Ka,100 calibration were also systematically smaller by about 1.5%. Despite of these systematical deviations, the agreement of the different methods was in almost all cases within the 1σ level of confidence of the interval of their respective uncertainties in a Gaussian distribution. The application of Monte Carlo based [Formula: see text] for the determination of Ka,100 for three μSelectron V2 sources

  20. SU-F-T-13: Transit Dose Comparisons for Co-60 and Ir-192 HDR Sources

    Energy Technology Data Exchange (ETDEWEB)

    Gimenez-Alventosa, V; Ballester, F [University of Valencia, Burjassot (Spain); Vijande, J [University of Valencia and IFIC(CSIC-UV), Burjassot (Spain); Perez-Calatayud, J [Hospital Clinica Benidorm, Benidorm, and Hospital Universitari i Politecnic La Fe, Valencia (Spain)

    2016-06-15

    Purpose: The purpose of this study is to compare the transit dose due to the movement of high dose rate (HDR) Ir-192 and Co-60 sources along the transfer tube. This is performed by evaluating air-kerma differences in the vicinity of the transfer tube when both sources are moved with the same velocity from a HDR brachytherapy afterloader into a patient. Methods: Monte Carlo simulations have been performed using PENELOPE2014. mHDR-v2 and Flexisource sources have been considered. Collisional kerma has been scored. The sources were simulated within a plastic catheter located in an infinite air phantom. The movement of the seed was included by displacing their positions along the connecting catheter from z=−75 cm to z=+75 cm and combining them. Backscatter from the afterloader and the patient was not considered. Since modern afterloaders like Flexitron (Elekta) or Saginova (Bebig) are able to use equally Ir-192 and Co-60 sources it was assumed that both sources are displaced with equal speed. Typical content activity values were provided by the manufacturer (460 GBq for Ir-192 and 75 GBq for Co-60). Results: 2D distributions were obtained with type-A uncertainties (k=2) less than 0.01%. From those, the air kerma ratio Co-60/Ir-192 was evaluated weighted by their corresponding activities. It was found that it varies slowly with distance (less than 10% variation) but strongly in time due to the shorter half-life of the Ir-192 (73.83 days). The maximum ratio is located close to the catheter with a value of 0.57 when both sources are installed by the manufacturer, while increasing up to 1.25 at the end of the recommended working life (90 days) of the Ir-192 source. Conclusion: Air-kerma ratios are almost constant (0.51–0.57) in the vicinity of the source. Nevertheless, air-kerma ratios increase rapidly whenever the Ir-192 is approaching the end of its life.

  1. HDR Brachytherapy in the Management of High-Risk Prostate Cancer

    Science.gov (United States)

    Masson, Susan; Persad, Raj; Bahl, Amit

    2012-01-01

    High-dose-rate (HDR) brachytherapy is used with increasing frequency for the treatment of prostate cancer. It is a technique which allows delivery of large individual fractions to the prostate without exposing adjacent normal tissues to unacceptable toxicity. This approach is particularly favourable in prostate cancer where tumours are highly sensitive to dose escalation and to increases in radiotherapy fraction size, due to the unique radiobiological behaviour of prostate cancers in contrast with other malignancies. In this paper we discuss the rationale and the increasing body of clinical evidence for the use of this technique in patients with high-risk prostate cancer, where it is combined with external beam radiotherapy. We highlight practical aspects of delivering treatment and discuss toxicity and limitations, with particular reference to current practice in the United Kingdom. PMID:22461791

  2. HDR Brachytherapy in the Management of High-Risk Prostate Cancer

    Directory of Open Access Journals (Sweden)

    Susan Masson

    2012-01-01

    Full Text Available High-dose-rate (HDR brachytherapy is used with increasing frequency for the treatment of prostate cancer. It is a technique which allows delivery of large individual fractions to the prostate without exposing adjacent normal tissues to unacceptable toxicity. This approach is particularly favourable in prostate cancer where tumours are highly sensitive to dose escalation and to increases in radiotherapy fraction size, due to the unique radiobiological behaviour of prostate cancers in contrast with other malignancies. In this paper we discuss the rationale and the increasing body of clinical evidence for the use of this technique in patients with high-risk prostate cancer, where it is combined with external beam radiotherapy. We highlight practical aspects of delivering treatment and discuss toxicity and limitations, with particular reference to current practice in the United Kingdom.

  3. Mixed integer programming improves comprehensibility and plan quality in inverse optimization of prostate HDR-brachytherapy

    CERN Document Server

    Gorissen, Bram L; Hoffmann, Aswin L

    2014-01-01

    Current inverse treatment planning methods that optimize both catheter positions and dwell times in prostate HDR brachytherapy use surrogate linear or quadratic objective functions that have no direct interpretation in terms of dose-volume histogram (DVH) criteria, do not result in an optimum or have long solution times. We decrease the solution time of existing linear and quadratic dose-based programming models (LP and QP, respectively) to allow optimizing over potential catheter positions using mixed integer programming. An additional average speed-up of 75% can be obtained by stopping the solver at an early stage, without deterioration of the plan quality. For a fixed catheter configuration, the dwell time optimization model LP solves to optimality in less than 15 seconds, which confirms earlier results. We propose an iterative procedure for QP that allows to prescribe the target dose as an interval, while retaining independence between the solution time and the number of dose calculation points. This iter...

  4. Video Enhancement and Dynamic Range Control of HDR Sequences for Automotive Applications

    Directory of Open Access Journals (Sweden)

    Giovanni Ramponi

    2007-01-01

    Full Text Available CMOS video cameras with high dynamic range (HDR output are particularly suitable for driving assistance applications, where lighting conditions can strongly vary, going from direct sunlight to dark areas in tunnels. However, common visualization devices can only handle a low dynamic range, and thus a dynamic range reduction is needed. Many algorithms have been proposed in the literature to reduce the dynamic range of still pictures. Anyway, extending the available methods to video is not straightforward, due to the peculiar nature of video data. We propose an algorithm for both reducing the dynamic range of video sequences and enhancing its appearance, thus improving visual quality and reducing temporal artifacts. We also provide an optimized version of our algorithm for a viable hardware implementation on an FPGA. The feasibility of this implementation is demonstrated by means of a case study.

  5. On the use of HDR 60Co source with the MammoSite radiation therapy system.

    Science.gov (United States)

    Baltas, D; Lymperopoulou, G; Zamboglou, N

    2008-12-01

    This work summarizes Monte Carlo results in order to evaluate the potential of using HDR 60Co sources in accelerated partial breast irradiation (APBI) with the MammoSite applicator. Simulations have been performed using the MCNP5 Monte Carlo Code, in simple geometries comprised of two concentric spheres; the internal consisting of selected concentrations, C, of a radiographic contrast solution in water (Omnipaque 300) to simulate the MammoSite balloon and the external consisting of water to simulate surrounding tissue. The magnitude of the perturbation of delivered dose due to the radiographic contrast medium used in the MammoSite applicator is calculated. At the very close vicinity of the balloon surface, a dose build-up region is observed, which leads to a dose overestimation by the treatment planning system (TPS) which depends on Omnipaque 300 solution concentration (and is in order of 2.3%, 3.0%, and 4.5%, respectively, at 1 mm away from the balloon - water interface, for C=10%, 15%, and 20%). However, dose overestimation by the TPS is minimal for points lying at the prescription distance (d=1 cm) or beyond, for all simulated concentrations and radii of MammoSite balloon. An analytical estimation of the integral dose outside the CTV in the simple geometries simulated shows that dose to the breast for MammoSite applications is expected to be comparable using HDR 60Co and 192Ir sources, and higher than that for 169Yb. The higher enegies of 60Co sources result to approximately twice radiation protection requirements as compared to 169Ir sources. However, they allow for more accurate dosimetry calculation with currently used treatment planning algorithms for 60Co sources, compared to 169Ir.

  6. Ir-192 HDR transit dose and radial dose function determination using alanine/EPR dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Calcina, Carmen S Guzman [Departamento de FIsica e Matematica, FFCLRP, Universidade de Sao Paulo, Av Bandeirantes 3900, 14040-901, Ribeirao Preto, SP (Brazil); Almeida, Adelaide de [Departamento de FIsica e Matematica, FFCLRP, Universidade de Sao Paulo, Av Bandeirantes 3900, 14040-901, Ribeirao Preto, SP (Brazil); Rocha, Jose R Oliveira [Setor de FIsica Medica-CEB-UNICAMP e Setor de Radioterapia-CAISM-UNICAMP (Brazil); Abrego, Felipe Chen [Departamento de FIsica e Matematica, FFCLRP, Universidade de Sao Paulo, Av Bandeirantes 3900, 14040-901, Ribeirao Preto, SP (Brazil); Baffa, Oswaldo [Departamento de FIsica e Matematica, FFCLRP, Universidade de Sao Paulo, Av Bandeirantes 3900, 14040-901, Ribeirao Preto, SP (Brazil)

    2005-03-21

    Source positioning close to the tumour in high dose rate (HDR) brachytherapy is not instantaneous. An increment of dose will be delivered during the movement of the source in the trajectory to its static position. This increment is the transit dose, often not taken into account in brachytherapeutic treatment planning. The transit dose depends on the prescribed dose, number of treatment fractions, velocity and activity of the source. Combining all these factors, the transit dose can be 5% higher than the prescribed absorbed dose value (Sang-Hyun and Muller-Runkel, 1994 Phys. Med. Biol. 39 1181-8, Nath et al 1995 Med. Phys. 22 209-34). However, it cannot exceed this percentage (Nath et al 1995). In this work, we use the alanine-EPR (electron paramagnetic resonance) dosimetric system using analysis of the first derivative of the signal. The transit dose was evaluated for an HDR system and is consistent with that already presented for TLD dosimeters (Bastin et al 1993 Int. J. Radiat. Oncol. Biol. Phys. 26 695-702). Also using the same dosimetric system, the radial dose function, used to evaluate the geometric dose degradation around the source, was determined and its behaviour agrees better with those obtained by Monte Carlo simulations (Nath et al 1995, Williamson and Nath 1991 Med. Phys. 18 434-48, Ballester et al 1997 Med. Phys. 24 1221-8, Ballester et al 2001 Phys. Med. Biol. 46 N79-90) than with TLD measurements (Nath et al 1990 Med. Phys. 17 1032-40)

  7. Dwell time modulation restrictions do not necessarily improve treatment plan quality for prostate HDR brachytherapy.

    Science.gov (United States)

    Balvert, Marleen; Gorissen, Bram L; den Hertog, Dick; Hoffmann, Aswin L

    2015-01-21

    Inverse planning algorithms for dwell time optimisation in interstitial high-dose-rate (HDR) brachytherapy may produce solutions with large dwell time variations within catheters, which may result in undesirable selective high-dose subvolumes. Extending the dwell time optimisation model with a dwell time modulation restriction (DTMR) that limits dwell time differences between neighboring dwell positions has been suggested to eliminate this problem. DTMRs may additionally reduce the sensitivity for uncertainties in dwell positions that inevitably result from catheter reconstruction errors and afterloader source positioning inaccuracies. This study quantifies the reduction of high-dose subvolumes and the robustness against these uncertainties by applying a DTMR to template-based prostate HDR brachytherapy implants. Three different DTMRs were consecutively applied to a linear dose-based penalty model (LD) and a dose-volume based model (LDV), both obtained from literature. The models were solved with DTMR levels ranging from no restriction to uniform dwell times within catheters in discrete steps. Uncertainties were simulated on clinical cases using in-house developed software, and dose-volume metrics were calculated in each simulation. For the assessment of high-dose subvolumes, the dose homogeneity index (DHI) and the contiguous dose volume histogram were analysed. Robustness was measured by the improvement of the lowest D90% of the planning target volume (PTV) observed in the simulations. For (LD), a DTMR yields an increase in DHI of approximately 30% and reduces the size of the largest high-dose volume by 2-5 cc. However, this comes at a cost of a reduction in D90% of the PTV of 10%, which often implies that it drops below the desired minimum of 100%. For (LDV), none of the DTMRs were able to improve high-dose volume measures. DTMRs were not capable of improving robustness of PTV D90% against uncertainty in dwell positions for both models.

  8. An automated optimization tool for high-dose-rate (HDR) prostate brachytherapy with divergent needle pattern

    Science.gov (United States)

    Borot de Battisti, M.; Maenhout, M.; de Senneville, B. Denis; Hautvast, G.; Binnekamp, D.; Lagendijk, J. J. W.; van Vulpen, M.; Moerland, M. A.

    2015-10-01

    Focal high-dose-rate (HDR) for prostate cancer has gained increasing interest as an alternative to whole gland therapy as it may contribute to the reduction of treatment related toxicity. For focal treatment, optimal needle guidance and placement is warranted. This can be achieved under MR guidance. However, MR-guided needle placement is currently not possible due to space restrictions in the closed MR bore. To overcome this problem, a MR-compatible, single-divergent needle-implant robotic device is under development at the University Medical Centre, Utrecht: placed between the legs of the patient inside the MR bore, this robot will tap the needle in a divergent pattern from a single rotation point into the tissue. This rotation point is just beneath the perineal skin to have access to the focal prostate tumor lesion. Currently, there is no treatment planning system commercially available which allows optimization of the dose distribution with such needle arrangement. The aim of this work is to develop an automatic inverse dose planning optimization tool for focal HDR prostate brachytherapy with needle insertions in a divergent configuration. A complete optimizer workflow is proposed which includes the determination of (1) the position of the center of rotation, (2) the needle angulations and (3) the dwell times. Unlike most currently used optimizers, no prior selection or adjustment of input parameters such as minimum or maximum dose or weight coefficients for treatment region and organs at risk is required. To test this optimizer, a planning study was performed on ten patients (treatment volumes ranged from 8.5 cm3to 23.3 cm3) by using 2-14 needle insertions. The total computation time of the optimizer workflow was below 20 min and a clinically acceptable plan was reached on average using only four needle insertions.

  9. Dwell time modulation restrictions do not necessarily improve treatment plan quality for prostate HDR brachytherapy

    Science.gov (United States)

    Balvert, Marleen; Gorissen, Bram L.; den Hertog, Dick; Hoffmann, Aswin L.

    2015-01-01

    Inverse planning algorithms for dwell time optimisation in interstitial high-dose-rate (HDR) brachytherapy may produce solutions with large dwell time variations within catheters, which may result in undesirable selective high-dose subvolumes. Extending the dwell time optimisation model with a dwell time modulation restriction (DTMR) that limits dwell time differences between neighboring dwell positions has been suggested to eliminate this problem. DTMRs may additionally reduce the sensitivity for uncertainties in dwell positions that inevitably result from catheter reconstruction errors and afterloader source positioning inaccuracies. This study quantifies the reduction of high-dose subvolumes and the robustness against these uncertainties by applying a DTMR to template-based prostate HDR brachytherapy implants. Three different DTMRs were consecutively applied to a linear dose-based penalty model (LD) and a dose-volume based model (LDV), both obtained from literature. The models were solved with DTMR levels ranging from no restriction to uniform dwell times within catheters in discrete steps. Uncertainties were simulated on clinical cases using in-house developed software, and dose-volume metrics were calculated in each simulation. For the assessment of high-dose subvolumes, the dose homogeneity index (DHI) and the contiguous dose volume histogram were analysed. Robustness was measured by the improvement of the lowest D90% of the planning target volume (PTV) observed in the simulations. For (LD), a DTMR yields an increase in DHI of approximately 30% and reduces the size of the largest high-dose volume by 2-5 cc. However, this comes at a cost of a reduction in D90% of the PTV of 10%, which often implies that it drops below the desired minimum of 100%. For (LDV), none of the DTMRs were able to improve high-dose volume measures. DTMRs were not capable of improving robustness of PTV D90% against uncertainty in dwell positions for both models.

  10. SU-F-T-11: Scintillator Based Quality Assurance Device for HDR Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Jozsef, G [New York University Medical Center, New York, NY (United States)

    2016-06-15

    Purpose: To build a test device for HDR afterloaders capable of checking source positions, times at positions and estimate the activity of the source. Methods: A catheter is taped on a plastic scintillation sheet. When a source travels through the catheter, the scintillator sheet lights up around the source. The sheet is monitored with a video camera, and records the movement of the light spot. The center of the spot on each image on the video provides the source location, and the time stamps of the images can provide the dwell time the source spend in each location. Finally, the brightness of the light spot is related to the activity of the source. A code was developed for noise removal, calibrate the scale of the image to centimeters, eliminate the distortion caused by the oblique view angle, identifying the boundaries of the light spot, transforming the image into binary and detect and calculate the source motion, positions and times. The images are much less noisy if the camera is shielded. That requires that the light spot is monitored in a mirror, rather than directly. The whole assembly is covered from external light and has a size of approximately 17×35×25cm (H×L×W) Results: A cheap camera in BW mode proved to be sufficient with a plastic scintillator sheet. The best images were resulted by a 3mm thick sheet with ZnS:Ag surface coating. The shielding of the camera decreased the noise, but could not eliminate it. A test run even in noisy condition resulted in approximately 1 mm and 1 sec difference from the planned positions and dwell times. Activity tests are in progress. Conclusion: The proposed method is feasible. It might simplify the monthly QA process of HDR Brachytherapy units.

  11. Virtual HDR CyberKnife SBRT for Localized Prostatic Carcinoma: 5-year Disease-free Survival and Toxicity Observations

    Directory of Open Access Journals (Sweden)

    Donald Blake Fuller

    2014-11-01

    Full Text Available PURPOSEProstate stereotactic body radiotherapy (SBRT may substantially recapitulate the dose distribution of high-dose-rate (HDR brachytherapy, representing an externally delivered Virtual HDR treatment method. Herein we present 5-year outcomes from a cohort of consecutively treated Virtual HDR SBRT prostate cancer patients.METHODSSeventy-nine patients were treated from 2006 - 2009, 40 low-risk and 39 intermediate-risk, under IRB-approved clinical trial, to 38 Gy in 4 fractions. The planning target volume (PTV included prostate plus a 2-mm volume expansion in all directions, with selective use of a 5-mm prostate-to-PTV expansion and proximal seminal vesicle coverage in intermediate-risk patients, to better cover potential extraprostatic disease; rectal PTV margin reduced to zero in all cases. The prescription dose covered > 95% of the PTV (V100 >= 95%, with a minimum 150% PTV dose escalation to create HDR-like PTV dose distribution.RESULTSMedian pre-SBRT PSA level of 5.6 ng/mL decreased to 0.05 ng/mL 5 years out and 0.02 ng/mL 6 years out. At least one PSA bounce was seen in 55 patients (70% but only 3 of them subsequently relapsed, Biochemical-relapse-free survival was 100% and 92% for low-risk and intermediate-risk patients, respectively, by ASTRO definition (98% and 92% by Phoenix definition. Local relapse did not occur, distant metastasis-free survival was 100% and 95% by risk-group, and disease-specific survival was 100%. Acute and late grade 2 GU toxicity incidence was 10% and 9%, respectively; with 6% late grade 3 GU toxicity. Acute urinary retention did not occur. Acute and late grade 2 GI toxicity was 0% and 1%, respectively, with no grade 3 or higher toxicity. Of patients potent pre-SBRT, 65% remained so at 5 years.CONCLUSIONSVirtual HDR prostate SBRT creates a very low PSA nadir, a high rate of 5-year disease-free survival and an acceptable toxicity incidence, with results closely resembling those reported post-HDR brachytherapy.

  12. [HDR 192Ir brachytherapy in treatment of basal cell carcinoma of the lower eyelid and inner angle - our experience].

    Science.gov (United States)

    Furdová, A; Lukačko, P; Lederleitner, D

    2013-06-01

    First experience and evaluation of relapses in group of patients after surgery with applied adjuvant HDR brachytherapy for recurrent tumor after incomplete excision of basal cell carcinoma of the lower eyelid and inner angle. Patients with recurrent basal cell carcinoma of the lower eyelid in year 2010. In 3 male patients with recurrent finding of basal cell after surgery we applied adjuvant HDR 192Ir brachytherapy. The isodose curve chosen to prescribe the dose was 5 mm away from the skin surface. In the year 2010 we applied adjuvant HDR 192Ir brachytherapy in 3 male patients with recurrent basal cell carcinoma. The average age was 58 years (52 to 75 years). From group of 41 patients with non melanotic malignant tumors of the eyelids in 3 patients (7.3 %) with relapse after incomplete excision of the basal cell carcinoma of the lower eyelid we applied after removal of stitches after surgery adjuvant HDR 192Ir brachytherapy. For each patient was made individual orfit mask that bore plastic applicators. Tungsten eye shield applicator was applied to protect the eye globe. Treatment of 10 fractions of 4.5 Gy single dose (5 times weekly) were scheduled within 2 weeks. Patients received outpatient treatment. Acute toxicity postradiation erythema of eyelid and skin around relieved by standard symptomatic treatment within a few days after completion of radiation therapy. In 2 year interval after HDR 192Ir brachytherapy we did not record the occurrence of late complications such as corneal ulcers. Our preliminary experience shows excellent early skin tolerance. After 2 years of follow-up at 6 month interval we did not recognize relapse in our group of patients. The proposed technique of HDR 192Ir brachytherapy after surgery should be considered a new clinical treatment in patients with recurrent non melanotic eyelid cancer. Its main advantage lies in the usefulness in all types of basal cell and squamous cell carcinoma and sebaceous carcinoma of the eyelids, without

  13. MR guided thermal therapy of pancreatic tumors with endoluminal, intraluminal and interstitial catheter-based ultrasound devices: preliminary theoretical and experimental investigations

    Science.gov (United States)

    Prakash, Punit; Salgaonkar, Vasant A.; Scott, Serena J.; Jones, Peter; Hensley, Daniel; Holbrook, Andrew; Plata, Juan; Sommer, Graham; Diederich, Chris J.

    2013-02-01

    Image-guided thermal interventions have been proposed for potential palliative and curative treatments of pancreatic tumors. Catheter-based ultrasound devices offer the potential for temporal and 3D spatial control of the energy deposition profile. The objective of this study was to apply theoretical and experimental techniques to investigate the feasibility of endogastric, intraluminal and transgastric catheter-based ultrasound for MR guided thermal therapy of pancreatic tumors. The transgastric approach involves insertion of a catheter-based ultrasound applicator (array of 1.5 mm OD x 10 mm transducers, 360° or sectored 180°, ~7 MHz frequency, 13-14G cooling catheter) directly into the pancreas, either endoscopically or via image-guided percutaneous placement. An intraluminal applicator, of a more flexible but similar construct, was considered for endoscopic insertion directly into the pancreatic or biliary duct. An endoluminal approach was devised based on an ultrasound transducer assembly (tubular, planar, curvilinear) enclosed in a cooling balloon which is endoscopically positioned within the stomach or duodenum, adjacent to pancreatic targets from within the GI tract. A 3D acoustic bio-thermal model was implemented to calculate acoustic energy distributions and used a FEM solver to determine the transient temperature and thermal dose profiles in tissue during heating. These models were used to determine transducer parameters and delivery strategies and to study the feasibility of ablating 1-3 cm diameter tumors located 2-10 mm deep in the pancreas, while thermally sparing the stomach wall. Heterogeneous acoustic and thermal properties were incorporated, including approximations for tumor desmoplasia and dynamic changes during heating. A series of anatomic models based on imaging scans of representative patients were used to investigate the three approaches. Proof of concept (POC) endogastric and transgastric applicators were fabricated and experimentally

  14. Clinical implementation and failure mode and effects analysis of HDR skin brachytherapy using Valencia and Leipzig surface applicators.

    Science.gov (United States)

    Sayler, Elaine; Eldredge-Hindy, Harriet; Dinome, Jessie; Lockamy, Virginia; Harrison, Amy S

    2015-01-01

    The planning procedure for Valencia and Leipzig surface applicators (VLSAs) (Nucletron, Veenendaal, The Netherlands) differs substantially from CT-based planning; the unfamiliarity could lead to significant errors. This study applies failure modes and effects analysis (FMEA) to high-dose-rate (HDR) skin brachytherapy using VLSAs to ensure safety and quality. A multidisciplinary team created a protocol for HDR VLSA skin treatments and applied FMEA. Failure modes were identified and scored by severity, occurrence, and detectability. The clinical procedure was then revised to address high-scoring process nodes. Several key components were added to the protocol to minimize risk probability numbers. (1) Diagnosis, prescription, applicator selection, and setup are reviewed at weekly quality assurance rounds. Peer review reduces the likelihood of an inappropriate treatment regime. (2) A template for HDR skin treatments was established in the clinic's electronic medical record system to standardize treatment instructions. This reduces the chances of miscommunication between the physician and planner as well as increases the detectability of an error. (3) A screen check was implemented during the second check to increase detectability of an error. (4) To reduce error probability, the treatment plan worksheet was designed to display plan parameters in a format visually similar to the treatment console display, facilitating data entry and verification. (5) VLSAs are color coded and labeled to match the electronic medical record prescriptions, simplifying in-room selection and verification. Multidisciplinary planning and FMEA increased detectability and reduced error probability during VLSA HDR brachytherapy. This clinical model may be useful to institutions implementing similar procedures. Copyright © 2015 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  15. A Feasibility Study of Fricke Dosimetry as an Absorbed Dose to Water Standard for 192Ir HDR Sources

    Science.gov (United States)

    deAlmeida, Carlos Eduardo; Ochoa, Ricardo; de Lima, Marilene Coelho; David, Mariano Gazineu; Pires, Evandro Jesus; Peixoto, José Guilherme; Salata, Camila; Bernal, Mario Antônio

    2014-01-01

    High dose rate brachytherapy (HDR) using 192Ir sources is well accepted as an important treatment option and thus requires an accurate dosimetry standard. However, a dosimetry standard for the direct measurement of the absolute dose to water for this particular source type is currently not available. An improved standard for the absorbed dose to water based on Fricke dosimetry of HDR 192Ir brachytherapy sources is presented in this study. The main goal of this paper is to demonstrate the potential usefulness of the Fricke dosimetry technique for the standardization of the quantity absorbed dose to water for 192Ir sources. A molded, double-walled, spherical vessel for water containing the Fricke solution was constructed based on the Fricke system. The authors measured the absorbed dose to water and compared it with the doses calculated using the AAPM TG-43 report. The overall combined uncertainty associated with the measurements using Fricke dosimetry was 1.4% for k = 1, which is better than the uncertainties reported in previous studies. These results are promising; hence, the use of Fricke dosimetry to measure the absorbed dose to water as a standard for HDR 192Ir may be possible in the future. PMID:25521914

  16. [High-resolution imaging of the layers of the gastrointestinal wall of pig and human specimens using an endoluminal MR receiver coil: correlation to histology].

    Science.gov (United States)

    Kramer, S; Palmowski, M; Macher-Göppinger, S; Müller, M; Volke, F; Düx, M; Kauczor, H-U; Grenacher, L

    2009-11-01

    High-resolution MR imaging of the layers of the gastrointestinal wall to provide a foundation for tumor staging based on morphological criteria. Over a period of 12 months, miscellaneous parts of the gastrointestinal tract of 15 human specimens and 30 porcine specimens were scanned using a 1.5 Tesla clinical MRI scanner combined with an endoluminal receiver coil. The sequences used were T 1-weighted opposed-phase, T 2-weighted turbo spin echo with fat saturation and fast T 2-weighted inversion recovery. The number of differentiable layers, their width and the signal intensity were documented. Then, the results were compared with histological specimens in order to link the imaged wall layers to the anatomical layers. Spearman's Rank Correlation was used to determine the soundness of the link between the images and their related histology. For both human and animal specimens, the MRI scanning produced 3 to 5, maximum 6 (pig), differentiable layers. The mucosa, submucosa and muscularis could be differentiated with a hyperintense, hypointense and intermediary signal, respectively. The subserosal layer displayed a hypointense signal. High-resolution MRI is able to produce differentiable images of the anatomical layers of the gastrointestinal wall in both humans and pigs. Accordingly, it is possible to use MR imaging to diagnose the extent of local tumor infiltration of the gastrointestinal wall.

  17. Tratamento endoluminal de aneurismas anastomóticos na aorta abdominal: relato de dois casos Endovascular treatment of abdominal aortic anastomotic aneurysms: report of two cases

    Directory of Open Access Journals (Sweden)

    Ricardo Aun

    2006-03-01

    Full Text Available Os aneurismas anastomóticos que envolvem a anastomose proximal de reconstruções do território aorto-ilíaco são graves, e as operações convencionais para sua correção são complexas e passíveis de graves complicações. Apresentamos dois casos de aneurismas de anastomoses proximais de enxerto aorto-bifemoral que ocorreram após 15 e 18 anos, respectivamente, de evolução dos enxertos e que foram corrigidos pela técnica endoluminal. Ambos os pacientes evoluíram bem e foram submetidos a controle pela tomografia computadorizada com 12 e 6 meses de evolução, respectivamente, com exclusão do aneurisma.Proximal anastomosis aneurysm is a rare and severe complication in aortofemoral bypass surgery. Surgical treatment is complex and has a high morbidity and mortality rate. We report two cases of proximal anastomosis aneurysm in late follow up of aortobifemoral bypass surgery, which occurred 15 and 18 years, respectively, after the bypasses and were repaired by the endovascular technique. Both patients progressed well and were submitted to 6- and 12-month follow-up CT scans showing aneurysm exclusion.

  18. Endoluminal ultrasound applicator with an integrated RF coil for high-resolution magnetic resonance imaging-guided high-intensity contact ultrasound thermotherapy

    Science.gov (United States)

    Rata, Mihaela; Salomir, Rares; Umathum, Reiner; Jenne, Jürgen; Lafon, Cyril; Cotton, François; Bock, Michael

    2008-11-01

    High-intensity contact ultrasound (HICU) under MRI guidance may provide minimally invasive treatment of endocavitary digestive tumors in the esophagus, colon or rectum. In this study, a miniature receive-only coil was integrated into an endoscopic ultrasound applicator to offer high-resolution MRI guidance of thermotherapy. A cylindrical plastic support with an incorporated single element flat transducer (9.45 MHz, water cooling tip) was made and equipped with a rectangular RF loop coil surrounding the active element. The integrated coil provided significantly higher sensitivity than a four-element extracorporeal phased array coil, and the standard deviation of the MR thermometry (SDT) improved up to a factor of 7 at 10 mm depth in tissue. High-resolution morphological images (T1w-TFE and IR-T1w-TSE with a voxel size of 0.25 × 0.25 × 3 mm3) and accurate thermometry data (the PRFS method with a voxel size of 0.5 × 0.5 × 5 mm3, 2.2 s/image, 0.3 °C voxel-wise SDT) were acquired in an ex vivo esophagus sample, on a clinical 1.5T scanner. The endoscopic device was actively operated under automatic temperature control, demonstrating a high level of accuracy (1.7% standard deviation, 1.1% error of mean value), which indicates that this technology may be suitable for HICU therapy of endoluminal cancer.

  19. Endoluminal ultrasound applicator with an integrated RF coil for high-resolution magnetic resonance imaging-guided high-intensity contact ultrasound thermotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Rata, Mihaela; Salomir, Rares; Lafon, Cyril [Inserm, U556, Universite de Lyon, Lyon, F-69003 (France); Umathum, Reiner; Jenne, Juergen; Bock, Michael [DKFZ, Innovative Cancer Diagnostics and Therapy, Heidelberg (Germany); Cotton, Francois [Universite Claude Bernard Lyon 1, Lyon F-69003 (France)], E-mail: rares.salomir@inserm.fr

    2008-11-21

    High-intensity contact ultrasound (HICU) under MRI guidance may provide minimally invasive treatment of endocavitary digestive tumors in the esophagus, colon or rectum. In this study, a miniature receive-only coil was integrated into an endoscopic ultrasound applicator to offer high-resolution MRI guidance of thermotherapy. A cylindrical plastic support with an incorporated single element flat transducer (9.45 MHz, water cooling tip) was made and equipped with a rectangular RF loop coil surrounding the active element. The integrated coil provided significantly higher sensitivity than a four-element extracorporeal phased array coil, and the standard deviation of the MR thermometry (SDT) improved up to a factor of 7 at 10 mm depth in tissue. High-resolution morphological images (T1w-TFE and IR-T1w-TSE with a voxel size of 0.25 x 0.25 x 3 mm{sup 3}) and accurate thermometry data (the PRFS method with a voxel size of 0.5 x 0.5 x 5 mm{sup 3}, 2.2 s/image, 0.3 deg. C voxel-wise SDT) were acquired in an ex vivo esophagus sample, on a clinical 1.5T scanner. The endoscopic device was actively operated under automatic temperature control, demonstrating a high level of accuracy (1.7% standard deviation, 1.1% error of mean value), which indicates that this technology may be suitable for HICU therapy of endoluminal cancer.

  20. A comparison between the new Low-profile Visualized Intraluminal Support (LVIS Blue) stent and the Flow Redirection Endoluminal Device (FRED) in bench-top and cadaver studies.

    Science.gov (United States)

    Matsuda, Yoshikazu; Chung, Joonho; Keigher, Kiffon; Lopes, Demetrius

    2017-09-22

    The aim of this study is to demonstrate the differences between the new Low-profile Visualized Intraluminal Support (LVIS Blue) stenting device and the Flow Redirection Endoluminal Device (FRED) using a series of bench-top evaluations and optical coherence tomography (OCT) images in a cadaveric preparation of the basilar artery. The first part of the evaluation was bench-top microscopic documentation of metal coverage for LVIS Blue and FRED stents. OCT images of the cerebral vessels and deployed stents were acquired using OCT intravascular imaging. The stents were deployed from the left posterior cerebral artery to the basilar artery in a fresh frozen cadaver. Wall apposition and the relationship to jailed perforators were evaluated. The metal coverage along the inner curves of the LVIS Blue stent was similar to that along the outer curves of the FRED stent. The LVIS Blue stent cell size was compatible for crossing with the tested microcatheters after deployment of the stent. The LVIS Blue stent showed better wall apposition and less coverage of the perforator than the FRED stent in the cadaver experiment. LVIS Blue has a good crossing profile for microcatheters, better wall apposition, and less perforator coverage than FRED. These are desirable features in territories with high densities of perforators such as the posterior circulation. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  1. Verification of dosimetry planning in brachytherapy in format Dicom and EUD calculation of Risk in bodies; Verificacion de la planificacion dosimetria en braquiterapia en formato Dicom y calculo del EUD en organos de riesgo

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Hernandez, M. J.; Sendon del Rio, J. R.; Ayala Lazaro, R.; Jimenez Rojas, M. R.; Gomez Cores, S.; Polo Cezon, R.; Lopez Bote, M. A.

    2013-07-01

    This work Describes a program that automates the verification of the schedules in brachytherapy (configuration and dosimetric treatment parameters) for sources of Ir-192 (mHDR v2) and Co-60 (Co0.A86) from the plan exported in DICOM format data. (Author)

  2. Calculation Monte Carlo equivalent dose to organs in a treatment of prostate with Brachytherapy of high rate; Calculo Monte Carlo de dosis equivalente a organos en un tratamiento de prostata con braquiterapia de alta tasa

    Energy Technology Data Exchange (ETDEWEB)

    Candela-Juan, C.; Vijande, J.; Granero, D.; Ballester, F.; Perez-Calatayud, J.; Rivard, M. J.

    2013-07-01

    The objective of this study was to obtain equivalent dose to radiosensitive organs when applies brachytherapy high dose (HDR) with sources of 60 Co or 192 Go to a localized carcinoma of the prostate. The results are compared with those reported in the literature on treatment with protons and intensity modulated (IMRT) radiation therapy. (Author)

  3. NPIP: A skew line needle configuration optimization system for HDR brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Siauw, Timmy; Cunha, Adam; Berenson, Dmitry; Atamtuerk, Alper; Hsu, I-Chow; Goldberg, Ken; Pouliot, Jean [Department of Civil and Environmental Engineering, University of California, Berkeley, 760 Davis Hall, Berkeley, California 94720-1710 (United States); Department of Radiation Oncology, University of California, San Francisco, Comprehensive Cancer Center, 1600 Divisadero Street, Suite H1031, San Francisco, California 94143-1708 (United States); Department of Electrical Engineering and Computer Science, University of California, Berkeley, 4th Floor Sutardja Dai Hall, Berkeley, California 94720-1764 (United States); Department of Industrial Engineering and Operations, University of California, Berkeley, 4141 Etcheverry Hall, Berkeley, California 94720-1777 (United States); Department of Radiation Oncology, University of California, San Francisco, Comprehensive Cancer Center, 1600 Divisadero Street, Suite H1031, San Francisco, California 94143-1708 (United States); Department of Industrial Engineering and Operations Research and Department of Electrical Engineering and Computer Science, University of California, Berkeley, 4141 Etcheverry Hall, Berkeley, California 94720-1777 (United States); Department of Radiation Oncology, University of California, San Francisco, Comprehensive Cancer Center, 1600 Divisadero Street, Suite H1031, San Francisco, California 94143-1708 (United States)

    2012-07-15

    Purpose: In this study, the authors introduce skew line needle configurations for high dose rate (HDR) brachytherapy and needle planning by integer program (NPIP), a computational method for generating these configurations. NPIP generates needle configurations that are specific to the anatomy of the patient, avoid critical structures near the penile bulb and other healthy structures, and avoid needle collisions inside the body. Methods: NPIP consisted of three major components: a method for generating a set of candidate needles, a needle selection component that chose a candidate needle subset to be inserted, and a dose planner for verifying that the final needle configuration could meet dose objectives. NPIP was used to compute needle configurations for prostate cancer data sets from patients previously treated at our clinic. NPIP took two user-parameters: a number of candidate needles, and needle coverage radius, {delta}. The candidate needle set consisted of 5000 needles, and a range of {delta} values was used to compute different needle configurations for each patient. Dose plans were computed for each needle configuration. The number of needles generated and dosimetry were analyzed and compared to the physician implant. Results: NPIP computed at least one needle configuration for every patient that met dose objectives, avoided healthy structures and needle collisions, and used as many or fewer needles than standard practice. These needle configurations corresponded to a narrow range of {delta} values, which could be used as default values if this system is used in practice. The average end-to-end runtime for this implementation of NPIP was 286 s, but there was a wide variation from case to case. Conclusions: The authors have shown that NPIP can automatically generate skew line needle configurations with the aforementioned properties, and that given the correct input parameters, NPIP can generate needle configurations which meet dose objectives and use as many

  4. Fast, automatic, and accurate catheter reconstruction in HDR brachytherapy using an electromagnetic 3D tracking system

    Energy Technology Data Exchange (ETDEWEB)

    Poulin, Eric; Racine, Emmanuel; Beaulieu, Luc, E-mail: Luc.Beaulieu@phy.ulaval.ca [Département de physique, de génie physique et d’optique et Centre de recherche sur le cancer de l’Université Laval, Université Laval, Québec, Québec G1V 0A6, Canada and Département de radio-oncologie et Axe Oncologie du Centre de recherche du CHU de Québec, CHU de Québec, 11 Côte du Palais, Québec, Québec G1R 2J6 (Canada); Binnekamp, Dirk [Integrated Clinical Solutions and Marketing, Philips Healthcare, Veenpluis 4-6, Best 5680 DA (Netherlands)

    2015-03-15

    Purpose: In high dose rate brachytherapy (HDR-B), current catheter reconstruction protocols are relatively slow and error prone. The purpose of this technical note is to evaluate the accuracy and the robustness of an electromagnetic (EM) tracking system for automated and real-time catheter reconstruction. Methods: For this preclinical study, a total of ten catheters were inserted in gelatin phantoms with different trajectories. Catheters were reconstructed using a 18G biopsy needle, used as an EM stylet and equipped with a miniaturized sensor, and the second generation Aurora{sup ®} Planar Field Generator from Northern Digital Inc. The Aurora EM system provides position and orientation value with precisions of 0.7 mm and 0.2°, respectively. Phantoms were also scanned using a μCT (GE Healthcare) and Philips Big Bore clinical computed tomography (CT) system with a spatial resolution of 89 μm and 2 mm, respectively. Reconstructions using the EM stylet were compared to μCT and CT. To assess the robustness of the EM reconstruction, five catheters were reconstructed twice and compared. Results: Reconstruction time for one catheter was 10 s, leading to a total reconstruction time inferior to 3 min for a typical 17-catheter implant. When compared to the μCT, the mean EM tip identification error was 0.69 ± 0.29 mm while the CT error was 1.08 ± 0.67 mm. The mean 3D distance error was found to be 0.66 ± 0.33 mm and 1.08 ± 0.72 mm for the EM and CT, respectively. EM 3D catheter trajectories were found to be more accurate. A maximum difference of less than 0.6 mm was found between successive EM reconstructions. Conclusions: The EM reconstruction was found to be more accurate and precise than the conventional methods used for catheter reconstruction in HDR-B. This approach can be applied to any type of catheters and applicators.

  5. A multicentre audit of HDR/PDR brachytherapy absolute dosimetry in association with the INTERLACE trial (NCT015662405)

    Science.gov (United States)

    Díez, P.; Aird, E. G. A.; Sander, T.; Gouldstone, C. A.; Sharpe, P. H. G.; Lee, C. D.; Lowe, G.; Thomas, R. A. S.; Simnor, T.; Bownes, P.; Bidmead, M.; Gandon, L.; Eaton, D.; Palmer, A. L.

    2017-12-01

    A UK multicentre audit to evaluate HDR and PDR brachytherapy has been performed using alanine absolute dosimetry. This is the first national UK audit performing an absolute dose measurement at a clinically relevant distance (20 mm) from the source. It was performed in both INTERLACE (a phase III multicentre trial in cervical cancer) and non-INTERLACE brachytherapy centres treating gynaecological tumours. Forty-seven UK centres (including the National Physical Laboratory) were visited. A simulated line source was generated within each centre’s treatment planning system and dwell times calculated to deliver 10 Gy at 20 mm from the midpoint of the central dwell (representative of Point A of the Manchester system). The line source was delivered in a water-equivalent plastic phantom (Barts Solid Water) encased in blocks of PMMA (polymethyl methacrylate) and charge measured with an ion chamber at 3 positions (120° apart, 20 mm from the source). Absorbed dose was then measured with alanine at the same positions and averaged to reduce source positional uncertainties. Charge was also measured at 50 mm from the source (representative of Point B of the Manchester system). Source types included 46 HDR and PDR 192Ir sources, (7 Flexisource, 24 mHDR-v2, 12 GammaMed HDR Plus, 2 GammaMed PDR Plus, 1 VS2000) and 1 HDR 60Co source, (Co0.A86). Alanine measurements when compared to the centres’ calculated dose showed a mean difference (±SD) of  +1.1% (±1.4%) at 20 mm. Differences were also observed between source types and dose calculation algorithm. Ion chamber measurements demonstrated significant discrepancies between the three holes mainly due to positional variation of the source within the catheter (0.4%–4.9% maximum difference between two holes). This comprehensive audit of absolute dose to water from a simulated line source showed all centres could deliver the prescribed dose to within 5% maximum difference between measurement and calculation.

  6. A comprehensive study on HDR brachytherapy treatments of cervical cancers: using the first Co-60 BEBIG Multisource Unit in Bangladesh

    Directory of Open Access Journals (Sweden)

    Naheed Rukhsana

    2011-07-01

    Full Text Available Purpose: The report presents an extraordinary synthesis of customer acceptance procedures (CAP, quality assurance tests (QA in the treatment of cervical cancer patients, using the first Co-60 Multisource Unit® in Bangladesh. The QA and commissioning required measurements and emergency tests verifying the functional limits of parameters acceptable for the new HDR afterloader. Acceptable limits were: 1 the deviation between specified and measured source strength: ± 3%; 2 the positional accuracy and uniformity: ± 1 mm; 3 the temporal accuracy (i.e. timer error and linearity and end error: ± 1% or 30 sec.; 4 treatment planning system (digitizer and localization software: ± 3% or 1 mm; 5 the distance from line to first dwell position and all the others: 5 mm and 10 mm (± 1 mm. Material and methods: Till February 2011, 47 patients were treated with HDR with more than 140 insertions applied. Amongst them, 12 patients were in stage IIB and IIIB, 22 were postoperative (IA and IB while the remaining 13 patients were with unknown stage. All the cases with stage IIB and IIIB received concurrent chemo-radiation and brachytherapy. Postoperative patients received EBRT (50 Gy and HDR according to the institutional protocol. CT scans were completed before HDR-plus planning with a good reproducibility (± 2% and were documented in repeating the plan for the same set up of a patient. Absorbed dose (Gy to a point P, at a distance of “r” in centimeters from a source of the Reference Air Kerma Rate (RAKR has been utilized for the QA of the source, where source strength measurement was accomplished. Results: All methods and analysis applicable to the QA and commissioning of Co-60 have been investigated and systematically analyzed, measured and documented before the treatment of a patient. Studies and safety requirements of this HDR remote afterloader were carried out. Acceptance and the QA were imperative to justify functionality and dependability in

  7. A comprehensive study on HDR brachytherapy treatments of cervical cancers: using the first Co-60 BEBIG Multisource Unit in Bangladesh.

    Science.gov (United States)

    Malik, Sadiq R; Banu, Parvin A; Rukhsana, Naheed

    2011-06-01

    The report presents an extraordinary synthesis of customer acceptance procedures (CAP), quality assurance tests (QA) in the treatment of cervical cancer patients, using the first Co-60 Multisource Unit® in Bangladesh. The QA and commissioning required measurements and emergency tests verifying the functional limits of parameters acceptable for the new HDR afterloader. Acceptable limits were: 1) the deviation between specified and measured source strength: ± 3%; 2) the positional accuracy and uniformity: ± 1 mm; 3) the temporal accuracy (i.e. timer error and linearity and end error): ± 1% or 30 sec.; 4) treatment planning system (digitizer and localization software): ± 3% or 1 mm; 5) the distance from line to first dwell position and all the others: 5 mm and 10 mm (± 1 mm). Till February 2011, 47 patients were treated with HDR with more than 140 insertions applied. Amongst them, 12 patients were in stage IIB and IIIB, 22 were postoperative (IA and IB) while the remaining 13 patients were with unknown stage. All the cases with stage IIB and IIIB received concurrent chemo-radiation and brachytherapy. Postoperative patients received EBRT (50 Gy and HDR) according to the institutional protocol. CT scans were completed before HDR-plus planning with a good reproducibility (± 2%) and were documented in repeating the plan for the same set up of a patient. Absorbed dose (Gy) to a point P, at a distance of "r" in centimeters from a source of the Reference Air Kerma Rate (RAKR) has been utilized for the QA of the source, where source strength measurement was accomplished. All methods and analysis applicable to the QA and commissioning of Co-60 have been investigated and systematically analyzed, measured and documented before the treatment of a patient. Studies and safety requirements of this HDR remote afterloader were carried out. Acceptance and the QA were imperative to justify functionality and dependability in delivering the treatment. Implications of these studies

  8. Catheter-based ultrasound hyperthermia with HDR brachytherapy for treatment of locally advanced cancer of the prostate and cervix

    Science.gov (United States)

    Diederich, Chris J.; Wootton, Jeff; Prakash, Punit; Salgaonkar, Vasant; Juang, Titania; Scott, Serena; Chen, Xin; Cunha, Adam; Pouliot, Jean; Hsu, I. C.

    2011-03-01

    A clinical treatment delivery platform has been developed and is being evaluated in a clinical pilot study for providing 3D controlled hyperthermia with catheter-based ultrasound applicators in conjunction with high dose rate (HDR) brachytherapy. Catheter-based ultrasound applicators are capable of 3D spatial control of heating in both angle and length of the devices, with enhanced radial penetration of heating compared to other hyperthermia technologies. Interstitial and endocavity ultrasound devices have been developed specifically for applying hyperthermia within HDR brachytherapy implants during radiation therapy in the treatment of cervix and prostate. A pilot study of the combination of catheter based ultrasound with HDR brachytherapy for locally advanced prostate and cervical cancer has been initiated, and preliminary results of the performance and heating distributions are reported herein. The treatment delivery platform consists of a 32 channel RF amplifier and a 48 channel thermocouple monitoring system. Controlling software can monitor and regulate frequency and power to each transducer section as required during the procedure. Interstitial applicators consist of multiple transducer sections of 2-4 cm length × 180 deg and 3-4 cm × 360 deg. heating patterns to be inserted in specific placed 13g implant catheters. The endocavity device, designed to be inserted within a 6 mm OD plastic tandem catheter within the cervix, consists of 2-3 transducers × dual 180 or 360 deg sectors. 3D temperature based treatment planning and optimization is dovetailed to the HDR optimization based planning to best configure and position the applicators within the catheters, and to determine optimal base power levels to each transducer section. To date we have treated eight cervix implants and six prostate implants. 100 % of treatments achieved a goal of >60 min duration, with therapeutic temperatures achieved in all cases. Thermal dosimetry within the hyperthermia target

  9. Monte Carlo characterization of the Gamma-Med Hdr plus Ir-192 brachytherapy source

    Energy Technology Data Exchange (ETDEWEB)

    Reyes, E.; Sosa, M. A.; Gil V, A. [Universidad de Guanajuato, Division de Ciencias e Ingenierias, Av. Insurgentes 2354, 37150 Leon, Guanajuato (Mexico); Monzon, E., E-mail: eric_1985@fisica.ugto.mx [IMSS, Unidad Medica de Alta Especialidad No. 1, Av. Adolfo Lopez Mateos 1813, 37340 Leon, Guanajuato (Mexico)

    2015-10-15

    Full text: The MCNP4C Monte Carlo code was used to simulate the dosimetry around the Gamma-Med Hdr Plus iridium-192 brachytherapy source in both air/vacuum and water environments. Dosimetry data in water was calculated and are presented into an away-along table. All dosimetric quantities recommended by the AAPM Task Group 43 report have been also calculated. These quantities are air kerma strength, dose rate constant, radial dose function and anisotropy function. The obtained data are compared to this source reference data, finding results in good agreement with them. In this study, recommendations of the AAPM TG-43U1 report have been followed and comply with the most recent AAPM and ESTRO physics committee recommendations about Monte Carlo techniques. The data in the present study complement published data and can be used as input in the Tps or as benchmark data to verify the results of the treatment planning systems as well as a means of comparison with other datasets from this source. (Author)

  10. Observing and characterizing avalanche activity in the Khumbu Himal, Nepal, using Pleiades and airborne HDR imagery

    Science.gov (United States)

    Thompson, Sarah; Nicholson, Lindsey; Klug, Christoph; Rieg, Lorenzo; Sailer, Rudolf; Bucher, Tilman; Brauchle, Jörg

    2017-04-01

    In the high, steep terrain of the Khumbu Himal, Nepal, snow avalanches play an important role in glacier mass balance, and rockfall supplies much of the rock material that forms the extensive debris covers on glaciers in the region. Information on the frequency and size of gravitational mass movements is helpful for understanding current and future glacier behaviour but currently lacking. In this study we use a combination of high resolution Pleiades optical satellite imagery in conjunction with airborne HDR imagery of slopes in deep shadow or overexposed snow slopes, provided by the German Aerospace Center (DLR) MACS system (see Brauchle et al., MM3.2/GI2.12/GMPV6.4/HS11.13/NH8.9/SSS12.24), to undertake a qualitative observational study of the gravitational processes evident in these sets of imagery. We classify the features found and discuss their likely frequency in the context of previously published research findings. Terrain analysis based upon digital terrain models derived from the same Pleiades imagery is used to investigate the slope angle, degree of confinement, curvature and aspect of observed avalanche and rock fall tracks. This work presents a first overview of the types of gravitational slides affecting glaciers of the Khumbu Himal. Subsequent research efforts will focus on attempting to quantify volumes of mass movement using repeat satellite imagery.

  11. Real-time verification of HDR brachytherapy source location: implementation of detector redundancy

    Science.gov (United States)

    Nakano, T.; Suchowerska, N.; McKenzie, D. R.; Bilek, M. M.

    2005-01-01

    Independent treatment verification for high dose rate (HDR) brachytherapy is needed to ensure that the treatment proceeds as prescribed. In this paper, we investigate the feasibility of a proposed real-time source position verification process. This process provides immediate confirmation of the source position during the treatment, so that the treatment can be aborted and modified if necessary. We show that an array of dosimeters placed on the patient's skin can independently verify the position in three dimensions. This verification was demonstrated by using a diamond detector placed in several locations on the surface of an anthropomorphic phantom. A mathematical algorithm was constructed to estimate the location of the source given a measured data set in the presence of tissue heterogeneity. The accuracy of the source localization was found to increase with the number of detectors used to compute the estimation of the source position. The resolution to which the 12 detectors can identify the location of the source was within 3 mm.

  12. Characterization of commercial MOSFET detectors and their feasibility for in-vivo HDR brachytherapy.

    Science.gov (United States)

    Phurailatpam, Reena; Upreti, Rituraj; Nojin Paul, Siji; Jamema, Swamidas V; Deshpande, Deepak D

    2016-01-01

    The present study was to investigate the use of MOSFET as an vivo dosimeter for the application of Ir-192 HDR brachytherapy treatments. MOSFET was characterized for dose linearity in the range of 50-1000 cGy, depth dose dependence from 2 to 7 cm, angular dependence. Signal fading was checked for two weeks. Dose linearity was found to be within 2% in the dose range (50-1000 cGy). The response varied within 8.07% for detector-source distance of 2-7 cm. The response of MOSFET with the epoxy side facing the source (0 degree) is the highest and the lowest response was observed at 90 and 270 degrees. Signal was stable during the study period. The detector showed high dose linearity and insignificant fading. But due to angular and depth dependence, care should be taken and corrections must be applied for clinical dosimetry. Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  13. Commissioning and quality assurance procedures for the HDR Valencia skin applicators

    Directory of Open Access Journals (Sweden)

    Domingo Granero

    2016-11-01

    Full Text Available The Valencia applicators (Nucletron, an Elekta company, Elekta AB, Stockholm, Sweden are cup-shaped tungsten applicators with a flattening filter used to collimate the radiation produced by a high-dose-rate (HDR 192 Ir source, and provide a homogeneous absorbed dose at a given depth. This beam quality provides a good option for the treatment of skin lesions at shallow depth (3-4 mm. The user must perform commissioning and periodic testing of these applicators to guarantee the proper and safe delivery of the intended absorbed dose, as recommended in the standards in radiation oncology. In this study, based on AAPM and GEC-ESTRO guidelines for brachytherapy units and our experience, a set of tests for the commissioning and periodic testing of the Valencia applicators is proposed. These include general considerations, verification of the manufacturer documentation and physical integrity, evaluation of the source-to-indexer distance and reproducibility, setting the library plan in the treatment planning system, evaluation of flatness and symmetry, absolute output and percentage depth dose verification, independent calculation of the treatment time, and visual inspection of the applicator before each treatment. For each test, the proposed methodology, equipment, frequency, expected results, and tolerance levels (when applicable are provided.

  14. Ahsa1 and Hsp90 activity confers more severe craniofacial phenotypes in a zebrafish model of hypoparathyroidism, sensorineural deafness and renal dysplasia (HDR

    Directory of Open Access Journals (Sweden)

    Kelly Sheehan-Rooney

    2013-09-01

    The severity of most human birth defects is highly variable. Our ability to diagnose, treat and prevent defects relies on our understanding of this variability. Mutation of the transcription factor GATA3 in humans causes the highly variable hypoparathyroidism, sensorineural deafness and renal dysplasia (HDR syndrome. Although named for a triad of defects, individuals with HDR can also exhibit craniofacial defects. Through a forward genetic screen for craniofacial mutants, we isolated a zebrafish mutant in which the first cysteine of the second zinc finger of Gata3 is mutated. Because mutation of the homologous cysteine causes HDR in humans, these zebrafish mutants could be a quick and effective animal model for understanding the role of gata3 in the HDR disease spectrum. We demonstrate that, unexpectedly, the chaperone proteins Ahsa1 and Hsp90 promote severe craniofacial phenotypes in our zebrafish model of HDR syndrome. The strengths of the zebrafish system, including rapid development, genetic tractability and live imaging, make this an important model for variability.

  15. Observation and simulation of non-laminar flow phenomena at the HDR site near Soulth-sous-forets; Beobachtung und Simulation von nicht-laminarem Fliessverhalten am HDR-Standort Soultz

    Energy Technology Data Exchange (ETDEWEB)

    Kohl, T. [ETH Hoenggerberg, Zuerich (Switzerland). Inst. fuer Geophysik; Evans, K.F.; Hopkirk, R.J. [Polydynamics Engineering, Maennedorf (Switzerland); Jung, R. [Bundesanstalt fuer Geowissenschaften und Rohstoffe, Hannover (Germany); Rybach, L. [ETH Hoenggerberg, Zuerich (Switzerland). Inst. fuer Geophysik und Radiometrie

    1997-12-01

    Three independent multi-rate flow experiments were conducted in 1994 and 1995 in the open hole depth interval of a wellbore at the Hot-Dry-Rocks (HDR) test site Soultz. The steady state and transient dowmhole pressure records gave clear indications of non-Darcian flow. A numerical model has been set-up to evaluate these two measurements. An excellent fit of the transient pressure responses of all three flow tests could be achieved by assuming a simple model geometry. The models predict fluid transport along a conduit with substantial surface area in which fully-turbulent flow is occurring. The parameters required by our best-fit simulation all fall into a physically reasonable range. Sensitivity analysis demonstrates a non-Darcian flow regime along highly conductive features. The existence of high capacity far-field faults as postulated in our model confirms earlier characterisations of the Soultz test site. (orig.) [Deutsch] In den Jahren 1994 und 1995 wurden drei unabhaengige Druck- bzw. Fliessratentests in den Bohrungen GPK1 und GPK2 des HDR Standortes Soultz durchgefuehrt. Sowohl die stationaeren wie auch die instationaeren Druckaufzeichnungen gaben bereits klare Hinweise auf nichtlaminare, turbulent-aehnliche Stroemungsverhaeltnisse. Zur genaueren Interpretation dieser Daten wurde das numerische Programm FRACTure erweitert. Unter der Annahme eines geometrisch einfachen Modells konnten die instationaeren Druckantworten sehr gut angepasst werden. Es gelang sogar, die beiden in GPK1 durchgefuehrten Tests durch dieselben Modelle zu erklaeren. Die hierfuer benoetigten Modellparameter liegen in einem physikalisch sinnvollem Rahmen und bestaetigen z.T. fruehere Untersuchungen. Die Existenz grosser Stoerungszonen, welche von den Modellen vorausgesetzt werden, bestaetigt ebenfalls fruehere Charakterisierungen des HDR Standortes Soultz als ein teilweise offenes hydraulisches System. (orig.)

  16. Towards a framework for analysis of eye-tracking studies in the three dimensional environment: a study of visual search by experienced readers of endoluminal CT colonography.

    Science.gov (United States)

    Helbren, E; Halligan, S; Phillips, P; Boone, D; Fanshawe, T R; Taylor, S A; Manning, D; Gale, A; Altman, D G; Mallett, S

    2014-05-01

    Eye tracking in three dimensions is novel, but established descriptors derived from two-dimensional (2D) studies are not transferable. We aimed to develop metrics suitable for statistical comparison of eye-tracking data obtained from readers of three-dimensional (3D) "virtual" medical imaging, using CT colonography (CTC) as a typical example. Ten experienced radiologists were eye tracked while observing eight 3D endoluminal CTC videos. Subsequently, we developed metrics that described their visual search patterns based on concepts derived from 2D gaze studies. Statistical methods were developed to allow analysis of the metrics. Eye tracking was possible for all readers. Visual dwell on the moving region of interest (ROI) was defined as pursuit of the moving object across multiple frames. Using this concept of pursuit, five categories of metrics were defined that allowed characterization of reader gaze behaviour. These were time to first pursuit, identification and assessment time, pursuit duration, ROI size and pursuit frequency. Additional subcategories allowed us to further characterize visual search between readers in the test population. We propose metrics for the characterization of visual search of 3D moving medical images. These metrics can be used to compare readers' visual search patterns and provide a reproducible framework for the analysis of gaze tracking in the 3D environment. This article describes a novel set of metrics that can be used to describe gaze behaviour when eye tracking readers during interpretation of 3D medical images. These metrics build on those established for 2D eye tracking and are applicable to increasingly common 3D medical image displays.

  17. Nucleotide-guided mesorectal excision combined with endoluminal locoregional resection by transanal endoscopic microsurgery in the treatment of rectal tumors: technique and preliminary results.

    Science.gov (United States)

    Lezoche, Emanuele; Fabiani, Bernardina; D'Ambrosio, Giancarlo; Ursi, Pietro; Balla, Andrea; Lezoche, Giovanni; Monteleone, Francesco; Paganini, Alessandro M

    2013-11-01

    Endoluminal locoregional resection (ELRR) by transanal endoscopic microsurgery (TEM) is an alternative treatment option for T1N0 rectal cancer and for selected patients with small T2N0 rectal cancer after neoadjuvant radiochemotherapy (n-RCT). The N parameter may remain undefined after transanal surgery. This study aimed to evaluate the role of a modified sentinel lymph node technique to improve N staging that the authors named "nucleotide-guided mesorectal excision" (NGME). The study enrolled 41 patients (24 men and 17 women) with a mean age of 70.5 years. Preoperative staging identified dysplasia with no suspicion for cancer at imaging (n = 8), dysplasia with suspected malignancy at imaging (n = 15), no suspicion of malignancy at imaging after n-RCT (n = 2), cT1N0 (n = 6), cT2N0 (n = 6), cT3N0 (n = 3), and cT3N1 (n = 1). The patients underwent ELRR by TEM with NGME. Before surgery, 99m-technetium-marked nanocolloid was injected into the peritumoral submucosa. After resection, the residual defect was probed to detect residual radioactivity. If present, hot mesorectal fat was excised. With NGME, the mesorectal lymph node harvest increased from 0 to 10. Lymph nodes were isolated in the specimen or in hot mesorectal fat of 20 patients, 8 of whom had undergone n-RCT. The mean lymph node harvest was 2.75 ± 3.01 (range 1-10) in the irradiated patients and 2.91 ± 1.62 (range 1-6) in the nonirradiated patients (p = 0.87). The average number of lymph nodes in the irradiated patients was higher than in a previous historical series. The use of NGME during ELRR by TEM increases the lymph node harvest and may improve staging accuracy after transanal surgery.

  18. A modified sentinel lymph node technique combined with endoluminal loco-regional resection for the treatment of rectal tumours: a 14-year experience.

    Science.gov (United States)

    Quaresima, S; Paganini, A M; D'Ambrosio, G; Ursi, P; Balla, A; Lezoche, E

    2017-12-01

    After endoluminal loco-regional resection (ELRR) by transanal endoscopic microsurgey (TEM) the N parameter may remain undefined. Nucleotide-guided mesorectal excision (NGME) improves the lymph node harvest. The aim of the present study is to evaluate the long-term oncological results after ELRR with NGME. A total of 57 patients were enrolled over the period January 2001 to June 2015. All patients underwent ELRR by TEM. Prior to surgery, 99 m-technetium-marked nanocolloid was injected into the peritumoural submucosa. After removal of the specimen, the residual defect was probed to detect any residual radioactivity and 'hot' mesorectal fat was excised. All patients were included in a 5-year follow-up programme. Significant radioactivity in the residual cavity was found in 28 out of 57 patients (49%). The mean number of lymph nodes harvest in irradiated and nonirradiated patients was 1.66 and 2.76, respectively. After 68.2 months' follow-up overall survival was 91.2%, disease-related mortality 3.5% and disease-free survival 89.5%. Two patients developed pulmonary metastases: one ypT3N0 patient underwent lung lobectomy after chemotherapy and one pT2N0 patient was managed with lung radiotherapy. Both patients are currently alive and disease-free at 48 months' follow-up. Two patients developed local recurrence 1 year after ELRR, both treated with neoadjuvant chemo-radiotherapy and total mesorectal excision. Comparing the present series with previous patients who did not undergo NGME, an increased number of harvested lymph nodes were observed, with a statistically significant difference (P = 0.0085). NGME during ELRR improves the lymph node harvest and staging accuracy. The long-term results showed satisfactory local (3.5%) and distant (7%) recurrence rates. Colorectal Disease © 2017 The Association of Coloproctology of Great Britain and Ireland.

  19. HDR {sup 192}Ir source speed measurements using a high speed video camera

    Energy Technology Data Exchange (ETDEWEB)

    Fonseca, Gabriel P. [Instituto de Pesquisas Energéticas e Nucleares—IPEN-CNEN/SP, São Paulo 05508-000, Brazil and Department of Radiation Oncology (MAASTRO), GROW School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht 6201 BN (Netherlands); Viana, Rodrigo S. S.; Yoriyaz, Hélio [Instituto de Pesquisas Energéticas e Nucleares—IPEN-CNEN/SP, São Paulo 05508-000 (Brazil); Podesta, Mark [Department of Radiation Oncology (MAASTRO), GROW School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht 6201 BN (Netherlands); Rubo, Rodrigo A.; Sales, Camila P. de [Hospital das Clínicas da Universidade de São Paulo—HC/FMUSP, São Paulo 05508-000 (Brazil); Reniers, Brigitte [Department of Radiation Oncology - MAASTRO, GROW School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht 6201 BN (Netherlands); Research Group NuTeC, CMK, Hasselt University, Agoralaan Gebouw H, Diepenbeek B-3590 (Belgium); Verhaegen, Frank, E-mail: frank.verhaegen@maastro.nl [Department of Radiation Oncology - MAASTRO, GROW School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht 6201 BN (Netherlands); Medical Physics Unit, Department of Oncology, McGill University, Montréal, Québec H3G 1A4 (Canada)

    2015-01-15

    Purpose: The dose delivered with a HDR {sup 192}Ir afterloader can be separated into a dwell component, and a transit component resulting from the source movement. The transit component is directly dependent on the source speed profile and it is the goal of this study to measure accurate source speed profiles. Methods: A high speed video camera was used to record the movement of a {sup 192}Ir source (Nucletron, an Elekta company, Stockholm, Sweden) for interdwell distances of 0.25–5 cm with dwell times of 0.1, 1, and 2 s. Transit dose distributions were calculated using a Monte Carlo code simulating the source movement. Results: The source stops at each dwell position oscillating around the desired position for a duration up to (0.026 ± 0.005) s. The source speed profile shows variations between 0 and 81 cm/s with average speed of ∼33 cm/s for most of the interdwell distances. The source stops for up to (0.005 ± 0.001) s at nonprogrammed positions in between two programmed dwell positions. The dwell time correction applied by the manufacturer compensates the transit dose between the dwell positions leading to a maximum overdose of 41 mGy for the considered cases and assuming an air-kerma strength of 48 000 U. The transit dose component is not uniformly distributed leading to over and underdoses, which is within 1.4% for commonly prescribed doses (3–10 Gy). Conclusions: The source maintains its speed even for the short interdwell distances. Dose variations due to the transit dose component are much lower than the prescribed treatment doses for brachytherapy, although transit dose component should be evaluated individually for clinical cases.

  20. Evaluation of PC-ISO for customized, 3D Printed, gynecologic 192-Ir HDR brachytherapy applicators.

    Science.gov (United States)

    Cunha, J Adam M; Mellis, Katherine; Sethi, Rajni; Siauw, Timmy; Sudhyadhom, Atchar; Garg, Animesh; Goldberg, Ken; Hsu, I-Chow; Pouliot, Jean

    2015-01-08

    The purpose of this study was to evaluate the radiation attenuation properties of PC-ISO, a commercially available, biocompatible, sterilizable 3D printing material, and its suitability for customized, single-use gynecologic (GYN) brachytherapy applicators that have the potential for accurate guiding of seeds through linear and curved internal channels. A custom radiochromic film dosimetry apparatus was 3D-printed in PC-ISO with a single catheter channel and a slit to hold a film segment. The apparatus was designed specifically to test geometry pertinent for use of this material in a clinical setting. A brachytherapy dose plan was computed to deliver a cylindrical dose distribution to the film. The dose plan used an 192Ir source and was normalized to 1500 cGy at 1 cm from the channel. The material was evaluated by comparing the film exposure to an identical test done in water. The Hounsfield unit (HU) distributions were computed from a CT scan of the apparatus and compared to the HU distribution of water and the HU distribution of a commercial GYN cylinder applicator. The dose depth curve of PC-ISO as measured by the radiochromic film was within 1% of water between 1 cm and 6 cm from the channel. The mean HU was -10 for PC-ISO and -1 for water. As expected, the honeycombed structure of the PC-ISO 3D printing process created a moderate spread of HU values, but the mean was comparable to water. PC-ISO is sufficiently water-equivalent to be compatible with our HDR brachytherapy planning system and clinical workflow and, therefore, it is suitable for creating custom GYN brachytherapy applicators. Our current clinical practice includes the use of custom GYN applicators made of commercially available PC-ISO when doing so can improve the patient's treatment. 

  1. The influence of the dwell time deviation constraint (DTDC) parameter on dosimetry with IPSA optimisation for HDR prostate brachytherapy.

    Science.gov (United States)

    Smith, Ryan L; Panettieri, Vanessa; Lancaster, Craig; Mason, Natasha; Franich, Rick D; Millar, Jeremy L

    2015-03-01

    To investigate how the dwell time deviation constraint (DTDC) parameter, applied to inverse planning by simulated annealing (IPSA) optimisation limits large dwell times from occurring in each catheter and to characterise the effect on the resulting dosimetry for prostate high dose rate (HDR) brachytherapy treatment plans. An unconstrained IPSA optimised treatment plan, using the Oncentra Brachytherapy treatment planning system (version 4.3, Nucletron an Elekta company, Elekta AB, Stockholm, Sweden), was generated for 20 consecutive HDR prostate brachytherapy patients, with the DTDC set to zero. Successive constrained optimisation plans were also created for each patient by increasing the DTDC parameter by 0.2, up to a maximum value of 1.0. We defined a "plan modulation index", to characterise the change of dwell time modulation as the DTDC parameter was increased. We calculated the dose volume histogram indices for the PTV (D90, V100, V150, V200%) and urethra (D10%) to characterise the effect on the resulting dosimetry. The average PTV D90% decreases as the DTDC is applied, on average by only 1.5 %, for a DTDC = 0.4. The measures of high dose regions in the PTV, V150 and V200%, increase on average by less than 5 and 2 % respectively. The net effect of DTDC on the modulation of dwell times has been characterised by the introduction of the plan modulation index. DTDC applied during IPSA optimisation of HDR prostate brachytherapy plans reduce the occurrence of large isolated dwell times within individual catheters. The mechanism by which DTDC works has been described and its effect on the modulation of dwell times has been characterised. The authors recommend using a DTDC parameter no greater than 0.4 to obtain a plan with dwell time modulation comparable to a geometric optimised plan. This yielded on average a 1.5 % decrease in PTV coverage and an acceptable increase in V150%, without compromising the urethral dose.

  2. SU-C-202-02: A Comprehensive Evaluation of Adaptive Daily Planning for Cervical Cancer HDR Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Meerschaert, R; Paul, A; Zhuang, L [Department of Oncology, Radiation Oncology Division, Wayne State University School of Medicine, Detroit, MI (United States); Nalichowski, A [Department of Oncology, Radiation Oncology Division, Karmanos Cancer Institute, Detroit, MI (United States); Burmeister, J; Miller, A [Department of Oncology, Radiation Oncology Division, Wayne State University School of Medicine, Detroit, MI (United States); Department of Oncology, Radiation Oncology Division, Karmanos Cancer Institute, Detroit, MI (United States)

    2016-06-15

    Purpose: To evaluate adaptive daily planning for cervical cancer patients who underwent high-dose-rate intra-cavitary brachytherapy (HDR-ICBT). Methods: This study included 22 cervical cancer patients who underwent 5 fractions of HDR ICBT. Regions of interest (ROIs) including high-risk clinical tumor volume (HR-CTV) and organs-at-risk (OARs) were manually contoured on daily CT images. All patients were treated with adaptive daily plans, which involved ROI delineation and dose optimization at each treatment fraction. Single treatment plans were retrospectively generated by applying the first treatment fraction’s dwell times adjusted for decay and dwell positions of the applicator to subsequent treatment fractions. Various existing similarity metrics were calculated for the ROIs to quantify interfractional organ variations. A novel similarity score (JRARM) was established, which combined both volumetric overlap metrics (DSC, JSC, and RVD) and distance metrics (ASD, MSD, and RMSD). Linear regression was performed to determine a relationship between inter-fractional organ variations of various similarity metrics and D2cc variations from both plans. Wilcoxon Signed Rank Tests were used to assess adaptive daily plans and single plans by comparing EQD2 D2cc (α/β=3) for OARs. Results: For inter-fractional organ variations, the sigmoid demonstrated the greatest variations based on the JRARM and DSC similarity metrics. Comparisons between paired ROIs showed differences in JRARM scores and DSCs at each treatment fraction. RVD, MSD, and RMSD were found to be significantly correlated to D2cc variations for bladder and sigmoid. The comparison between plans found that adaptive daily planning provided lower EQD2 D2cc of OARs than single planning, specifically for the sigmoid (p=0.015). Conclusion: Substantial inter-fractional organ motion can occur during HDR-BT, which may significantly affect D2cc of OARs. Adaptive daily planning provides improved dose sparing for OARs

  3. SU-C-16A-05: OAR Dose Tolerance Recommendations for Prostate and Cervical HDR Brachytherapy: Dose Versus Volume Metrics

    Energy Technology Data Exchange (ETDEWEB)

    Geneser, S; Cunha, J; Pouliot, J; Hsu, I [UC San Francisco, San Francisco, CA (United States)

    2014-06-15

    Purpose: HDR brachytherapy consensus dose tolerance recommendations for organs at risk (OARs) remain widely debated. Prospective trials reporting metrics must be sufficiently data-dense to assess adverse affects and identify optimally predictive tolerances. We explore the tradeoffs between reporting dose-metrics versus volume-metrics and the potential impact on trial outcome analysis and tolerance recommendations. Methods: We analyzed 26 prostate patients receiving 15 Gy HDR single-fraction brachytherapy boost to 45 Gy external beam radiation therapy and 28 cervical patients receiving 28 Gy HDR brachytherapy monotherapy in 4 fractions using 2 implants. For each OAR structure, a robust linear regression fit was performed for the dose-metrics as a function of the volume-metrics. The plan quality information provided by recommended dose-metric and volume-metric values were compared. Results: For prostate rectal dose, D2cc and V75 lie close to the regression line, indicating they are similarly informative. Two outliers for prostate urethral dose are substantially different from the remaining cohort in terms of D0.1cc and V75, but not D1cc, suggesting the choice of reporting dose metric is essential. For prostate bladder and cervical bladder, rectum, and bowel, dose outliers are more apparent via V75 than recommended dose-metrics. This suggests that for prostate bladder dose and all cervical OAR doses, the recommended volume-metrics may be better predictors of clinical outcome than dose-metrics. Conclusion: For plan acceptance criteria, dose and volume-metrics are reciprocally equivalent. However, reporting dosemetrics or volume-metrics alone provides substantially different information. Our results suggest that volume-metrics may be more sensitive to differences in planned dose, and if one metric must be chosen, volumemetrics are preferable. However, reporting discrete DVH points severely limits the ability to identify planning tolerances most predictive of adverse

  4. Medically inoperable endometrial cancer in patients with a high body mass index (BMI): Patterns of failure after 3-D image-based high dose rate (HDR) brachytherapy

    DEFF Research Database (Denmark)

    Acharya, Sahaja; Esthappan, Jacqueline; Badiyan, Shahed

    2016-01-01

    BACKGROUND AND PURPOSE: High BMI is a reason for medical inoperability in patients with endometrial cancer in the United States. Definitive radiation is an alternative therapy for these patients; however, data on patterns of failure after definitive radiotherapy are lacking. We describe...... the patterns of failure after definitive treatment with 3-D image-based high dose rate (HDR) brachytherapy for medically inoperable endometrial cancer. MATERIALS AND METHODS: Forty-three consecutive patients with endometrial cancer FIGO stages I-III were treated definitively with HDR brachytherapy...

  5. Devising an endoluminal bimodal probe which combines autofluorescence and reflectance spectroscopy with high resolution MRI for early stage colorectal cancer diagnosis: technique, feasibility and preliminary in-vivo (rabbit) results

    Science.gov (United States)

    Ramgolam, A.; Sablong, R.; Bou-Saïd, B.; Bouvard, S.; Saint-Jalmes, H.; Beuf, O.

    2011-07-01

    Conventional white light endoscopy (WLE) is the most widespread technique used today for colorectal cancer diagnosis and is considered as the gold standard when coupled to biopsy and histology. However for early stage colorectal cancer diagnosis, which is very often characterised by flat adenomas, the use of WLE is quite difficult due to subtle or quasiinvisible morphological changes of the colonic lining. Figures worldwide point out that diagnosing colorectal cancer in its early stages would significantly reduce the death toll all while increasing the 5-year survival rate. Several techniques are currently being investigated in the scope of providing new tools that would allow such a diagnostic or assist actual techniques in so doing. We hereby present a novel technique where High spatial Resolution MRI (HR-MRI) is coupled to optical spectroscopy (autofluorescence and reflectance) in a bimodal endoluminal probe to extract morphological data and biochemical information respectively. The design and conception of the endoluminal probe along with the preliminary results obtained with an organic phantom and in-vivo (rabbit) are presented and discussed.

  6. Optical spectroscopy combined with high-resolution magnetic resonance imaging for digestive wall assessment: endoluminal bimodal probe conception and characterization in vitro, on organic sample and in vivo on a rabbit

    Science.gov (United States)

    Ramgolam, Anoop; Sablong, Raphaël; Lafarge, Lionel; Saint-Jalmes, Hervé; Beuf, Olivier

    2011-11-01

    Colorectal cancer is a major health issue worldwide. Conventional white light endoscopy (WLE) coupled to histology is considered as the gold standard today and is the most widespread technique used for colorectal cancer diagnosis. However, during the early stages, colorectal cancer is very often characterized by flat adenomas which develop just underneath the mucosal surface. The use of WLE, which is heavily based on the detection of morphological changes, becomes quite delicate due to subtle or quasi-invisible morphological changes of the colonic lining. Several techniques are currently being investigated in the scope of providing new tools that would allow such a diagnostic or assist actual techniques in so doing. We hereby present a novel technique where high spatial resolution MRI is combined with autofluorescence and reflectance spectroscopy in a bimodal endoluminal probe to extract morphological data and biochemical information, respectively. The design and conception of the endoluminal probe are detailed and the promising preliminary results obtained in vitro (home-built phantom containing eosin and rhodamine B), on an organic sample (the kiwi fruit) and in vivo on a rabbit are presented and discussed.

  7. Investigation of Dosimetric Parameters of $^{192}$Ir MicroSelectron v2 HDR Brachytherapy Source Using EGSnrc Monte Carlo Code

    CERN Document Server

    Naeem, Hamza; Zheng, Huaqing; Cao, Ruifen; Pei, Xi; Hu, Liqin; Wu, Yican

    2016-01-01

    The $^{192}$Ir sources are widely used for high dose rate (HDR) brachytherapy treatments. The aim of this study is to simulate $^{192}$Ir MicroSelectron v2 HDR brachytherapy source and calculate the air kerma strength, dose rate constant, radial dose function and anisotropy function established in the updated AAPM Task Group 43 protocol. The EGSnrc Monte Carlo (MC) code package is used to calculate these dosimetric parameters, including dose contribution from secondary electron source and also contribution of bremsstrahlung photons to air kerma strength. The Air kerma strength, dose rate constant and radial dose function while anisotropy functions for the distance greater than 0.5 cm away from the source center are in good agreement with previous published studies. Obtained value from MC simulation for air kerma strength is $9.762\\times 10^{-8} \\textrm{UBq}^{-1}$and dose rate constant is $1.108\\pm 0.13\\%\\textrm{cGyh}^{-1} \\textrm{U}^{-1}$.

  8. SU-C-16A-03: Direction Modulated Brachytherapy for HDR Treatment of Cervical Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Han, D; Webster, M; Scanderbeg, D; Yashar, C; Choi, D; Song, B; Song, W [University of California, San Diego, La Jolla, CA (United States); Devic, S [McGill University, Montreal, QC (Canada); Ravi, A [Sunnybrook Odette Cancer Centre, Toronto (Canada)

    2014-06-15

    Purpose: To investigate a new Directional Modulated Brachytherapy (DMBT) intra-uterine tandem using various 192-Ir after-loaders. Methods: Dose distributions from the 192-Ir sources were modulated using a 6.3mm diameter tungsten shield (18.0g/cm3). The source moved along 6 longitudinal grooves, each 1.3mm in diameter, evenly spaced along periphery of the shield, The tungsten rod was enclosqed by 0.5mm thick Delrin (1.41g/cc). Monte Carlo N particle (MCNPX) was used to calculate dose distributions. 51million particles were calculated on 504 cores of a supercomputer. Fifteen different patients originally treated with a traditional tandem-and-ovoid applicator, with 5 fractions each, (15 patients X 5 fxs = 75 plans) were re-planned with the DMBT applicator combined with traditional ovoids, on an in-house developed HDR brachytherapy planning platform, which used intensity modulated planning capabilities using a constrained gradient optimization algorithm. For all plans the prescription dose was 6 Gy and they were normalized to match the clinical treated V100. Results: Generally, the DMBT plan quality was a remarkable improvement from conventional T and O plans because of the anisotropic dose distribution of DMBT. The largest difference was to the bladder which had a 0.59±0.87 Gy (8.5±28.7%) reduction in dose. This was because of the the horseshoe shape (U-shape) of the bladder. The dose reduction to rectum and sigmoid were 0.48±0.55 Gy (21.1±27.2%) and 0.10±0.38 Gy (40.6±214.9%), respectively. The D90 to the HRCTV was 6.55±0.96 Gy (conventional T and O) and 6.59±1.06 Gy (DMBT). Conclusion: For image guided adaptive brachytherapy, greater flexibility of radiation intensity is essential and DMBT can be the solution.

  9. Faulting mechanisms and stress regime at the European HDR site of Soultz-sous-Forets, France

    Energy Technology Data Exchange (ETDEWEB)

    Cuenot, Nicolas; Charlety, Jean; Haessler, Henri [Institut de Physique du Globe de Strasbourg, Ecole et Observatoire des Sciences de la Terre (IPGS-EOST), 5 rue Rene Descartes, 67084 Strasbourg Cedex (France); Dorbath, Louis [Institut de Physique du Globe de Strasbourg, Ecole et Observatoire des Sciences de la Terre (IPGS-EOST), 5 rue Rene Descartes, 67084 Strasbourg Cedex (France); Institut de Recherche pour le Developpement, Laboratoire des Mecanismes et Transferts en Geologie (IRD, LMTG), 14 Avenue Edouard Belin, 31400 Toulouse (France)

    2006-10-15

    The state of stress and its implications for shear on fault planes during fluid injection are crucial issues for the HDR (Hot Dry Rock) or EGS (Enhanced or Engineered Geothermal System) concept. This is especially true for hydraulic stimulation experiments, aimed at enhancing the connectivity of a borehole to the natural fracture network, since they tend to induce the shearing of fractures, which is controlled by the local stress regime. During the 2000 and 2003 stimulation tests at Soultz-sous-Forets, France, about 10,000 microearthquakes were located with a surface seismological network. Hundreds of double-couple (DC) focal mechanisms were automatically determined from first-motion polarities using the FPFIT program [Reasenberg, P.A., Oppenheimer, D., 1985. FPFIT, FPPLOT and FPPAGE: Fortran computer programs for calculating and displaying earthquake fault-plane solutions. US Geological Survey Open-File Report 85-739, 25 pp.]. The majority of these mechanisms indicate normal-faulting movement with a more or less pronounced strike-slip component. Some quasi-pure strike-slip events also occurred, especially in the deeper part of the stimulated rock volume, at more than 5 km depth. Although we found a double-couple solution for all events, we tried to observe and quantify the proportion of the non-double-couple (NDC) component in the seismic moment tensor for several microseisms from the 2003 data. The study shows that the NDC is higher for the events in the vicinity of the injection well than for the events far from the well. We used the method of Rivera and Cisternas [Rivera, L., Cisternas, A., 1990. Stress tensor and fault-plane solutions for a population of earthquakes. Bull. Seismol. Soc. Am. 80, 600-614.] to perform the inversion of the deviatoric part of the stress tensor from P-wave polarities. This method was applied to different datasets from the 2000 test, taken from the shallower and deeper parts of the stimulated region. The results show a stable

  10. SU-E-T-362: Automatic Catheter Reconstruction of Flap Applicators in HDR Surface Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Buzurovic, I; Devlin, P; Hansen, J; O' Farrell, D; Bhagwat, M; Friesen, S; Damato, A; Lewis, J; Cormack, R [Dana-Farber/Brigham and Women' s Cancer Center, Harvard Medical School, Boston, MA (United States)

    2014-06-01

    Purpose: Catheter reconstruction is crucial for the accurate delivery of radiation dose in HDR brachytherapy. The process becomes complicated and time-consuming for large superficial clinical targets with a complex topology. A novel method for the automatic catheter reconstruction of flap applicators is proposed in this study. Methods: We have developed a program package capable of image manipulation, using C++class libraries of The-Visualization-Toolkit(VTK) software system. The workflow for automatic catheter reconstruction is: a)an anchor point is placed in 3D or in the axial view of the first slice at the tip of the first, last and middle points for the curved surface; b)similar points are placed on the last slice of the image set; c)the surface detection algorithm automatically registers the points to the images and applies the surface reconstruction filter; d)then a structured grid surface is generated through the center of the treatment catheters placed at a distance of 5mm from the patient's skin. As a result, a mesh-style plane is generated with the reconstructed catheters placed 10mm apart. To demonstrate automatic catheter reconstruction, we used CT images of patients diagnosed with cutaneous T-cell-lymphoma and imaged with Freiburg-Flap-Applicators (Nucletron™-Elekta, Netherlands). The coordinates for each catheter were generated and compared to the control points selected during the manual reconstruction for 16catheters and 368control point Results: The variation of the catheter tip positions between the automatically and manually reconstructed catheters was 0.17mm(SD=0.23mm). The position difference between the manually selected catheter control points and the corresponding points obtained automatically was 0.17mm in the x-direction (SD=0.23mm), 0.13mm in the y-direction (SD=0.22mm), and 0.14mm in the z-direction (SD=0.24mm). Conclusion: This study shows the feasibility of the automatic catheter reconstruction of flap applicators with a high

  11. Gold marker displacement due to needle insertion during HDR-brachytherapy for treatment of prostate cancer: A prospective cone beam computed tomography and kilovoltage on-board imaging (kV-OBI study

    Directory of Open Access Journals (Sweden)

    Herrmann Markus KA

    2012-02-01

    Full Text Available Abstract Purpose To evaluate gold marker displacement due to needle insertion during HDR-brachytherapy for therapy of prostate cancer. Patients and methods 18 patients entered into this prospective evaluation. Three gold markers were implanted into the prostate during the first HDR-brachytherapy procedure after the irradiation was administered. Three days after marker implantation all patients had a CT-scan for planning purpose of the percutaneous irradiation. Marker localization was defined on the digitally-reconstructed-radiographs (DRR for daily (VMAT technique or weekly (IMRT set-up error correction. Percutaneous therapy started one week after first HDR-brachytherapy. After the second HDR-brachytherapy, two weeks after first HDR-brachtherapy, a cone-beam CT-scan was done to evaluate marker displacement due to needle insertion. In case of marker displacement, the actual positions of the gold markers were adjusted on the DRR. Results The value of the gold marker displacement due to the second HDR-brachytherapy was analyzed in all patients and for each gold marker by comparison of the marker positions in the prostate after soft tissue registration of the prostate of the CT-scans prior the first and second HDR-brachytherapy. The maximum deviation was 5 mm, 7 mm and 12 mm for the anterior-posterior, lateral and superior-inferior direction. At least one marker in each patient showed a significant displacement and therefore new marker positions were adjusted on the DRRs for the ongoing percutaneous therapy. Conclusions Needle insertion in the prostate due to HDR-brachytherapy can lead to gold marker displacements. Therefore, it is necessary to verify the actual position of markers after the second HDR-brachytherapy. In case of significant deviations, a new DRR with the adjusted marker positions should be generated for precise positioning during the ongoing percutaneous irradiation.

  12. Increasing Fractional Doses Increases the Probability of Benign PSA Bounce in Patients Undergoing Definitive HDR Brachytherapy for Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Hauck, Carlin R.; Ye, Hong; Chen, Peter Y.; Gustafson, Gary S.; Limbacher, Amy; Krauss, Daniel J., E-mail: Daniel.krauss@beaumont.edu

    2017-05-01

    Purpose: Prostate-specific antigen (PSA) bounce is a temporary elevation of the PSA level above a prior nadir. The purpose of this study was to determine whether the frequency of a PSA bounce following high-dose-rate (HDR) interstitial brachytherapy for the treatment of prostate cancer is associated with individual treatment fraction size. Methods and Materials: Between 1999 and 2014, 554 patients underwent treatment of low- or intermediate-risk prostate cancer with definitive HDR brachytherapy as monotherapy and had ≥3 subsequent PSA measurements. Four different fraction sizes were used: 950 cGy × 4 fractions, 1200 cGy × 2 fractions, 1350 cGy × 2 fractions, 1900 cGy × 1 fraction. Four definitions of PSA bounce were applied: ≥0.2, ≥0.5, ≥1.0, and ≥2.0 ng/mL above the prior nadir with a subsequent return to the nadir. Results: The median follow-up period was 3.7 years. The actuarial 3-year rate of PSA bounce for the entire cohort was 41.3%, 28.4%, 17.4%, and 6.8% for nadir +0.2, +0.5, +1.0, and +2.0 ng/mL, respectively. The 3-year rate of PSA bounce >0.2 ng/mL was 42.2%, 32.1%, 41.0%, and 59.1% for the 950-, 1200-, 1350-, and 1900-cGy/fraction levels, respectively (P=.002). The hazard ratio for bounce >0.2 ng/mL for patients receiving a single fraction of 1900 cGy compared with those receiving treatment in multiple fractions was 1.786 (P=.024). For patients treated with a single 1900-cGy fraction, the 1-, 2-, and 3-year rates of PSA bounce exceeding the Phoenix biochemical failure definition (nadir +2 ng/mL) were 4.5%, 18.7%, and 18.7%, respectively, higher than the rates for all other administered dose levels (P=.025). Conclusions: The incidence of PSA bounce increases with single-fraction HDR treatment. Knowledge of posttreatment PSA kinetics may aid in decision making regarding management of potential biochemical failures.

  13. Endocervical ultrasound applicator for integrated hyperthermia and HDR brachytherapy in the treatment of locally advanced cervical carcinoma

    Science.gov (United States)

    Wootton, Jeffery H.; Hsu, I-Chow Joe; Diederich, Chris J.

    2011-01-01

    Purpose: The clinical success of hyperthermia adjunct to radiotherapy depends on adequate temperature elevation in the tumor with minimal temperature rise in organs at risk. Existing technologies for thermal treatment of the cervix have limited spatial control or rapid energy falloff. The objective of this work is to develop an endocervical applicator using a linear array of multisectored tubular ultrasound transducers to provide 3-D conformal, locally targeted hyperthermia concomitant to radiotherapy in the uterine cervix. The catheter-based device is integrated within a HDR brachytherapy applicator to facilitate sequential and potentially simultaneous heat and radiation delivery. Methods: Treatment planning images from 35 patients who underwent HDR brachytherapy for locally advanced cervical cancer were inspected to assess the dimensions of radiation clinical target volumes (CTVs) and gross tumor volumes (GTVs) surrounding the cervix and the proximity of organs at risk. Biothermal simulation was used to identify applicator and catheter material parameters to adequately heat the cervix with minimal thermal dose accumulation in nontargeted structures. A family of ultrasound applicators was fabricated with two to three tubular transducers operating at 6.6–7.4 MHz that are unsectored (360°), bisectored (2×180°), or trisectored (3×120°) for control of energy deposition in angle and along the device length in order to satisfy anatomical constraints. The device is housed in a 6 mm diameter PET catheter with cooling water flow for endocervical implantation. Devices were characterized by measuring acoustic efficiencies, rotational acoustic intensity distributions, and rotational temperature distributions in phantom. Results: The CTV in HDR brachytherapy plans extends 20.5±5.0 mm from the endocervical tandem with the rectum and bladder typically 5EM43 °C over 4–5 cm diameter with Tmaxconformal thermal delivery to the uterine cervix. Feasibility of heating

  14. Radiobiological evaluation of the influence of dwell time modulation restriction in HIPO optimized HDR prostate brachytherapy implants.

    Science.gov (United States)

    Mavroidis, Panayiotis; Katsilieri, Zaira; Kefala, Vasiliki; Milickovic, Natasa; Papanikolaou, Nikos; Karabis, Andreas; Zamboglou, Nikolaos; Baltas, Dimos

    2010-09-01

    One of the issues that a planner is often facing in HDR brachytherapy is the selective existence of high dose volumes around some few dominating dwell positions. If there is no information available about its necessity (e.g. location of a GTV), then it is reasonable to investigate whether this can be avoided. This effect can be eliminated by limiting the free modulation of the dwell times. HIPO, an inverse treatment plan optimization algorithm, offers this option. In treatment plan optimization there are various methods that try to regularize the variation of dose non-uniformity using purely dosimetric measures. However, although these methods can help in finding a good dose distribution they do not provide any information regarding the expected treatment outcome as described by radiobiology based indices. The quality of 12 clinical HDR brachytherapy implants for prostate utilizing HIPO and modulation restriction (MR) has been compared to alternative plans with HIPO and free modulation (without MR). All common dose-volume indices for the prostate and the organs at risk have been considered together with radiobiological measures. The clinical effectiveness of the different dose distributions was investigated by calculating the response probabilities of the tumors and organs-at-risk (OARs) involved in these prostate cancer cases. The radiobiological models used are the Poisson and the relative seriality models. Furthermore, the complication-free tumor control probability, P+ and the biologically effective uniform dose ([Formula: see text]) were used for treatment plan evaluation and comparison. Our results demonstrate that HIPO with a modulation restriction value of 0.1-0.2 delivers high quality plans which are practically equivalent to those achieved with free modulation regarding the clinically used dosimetric indices. In the comparison, many of the dosimetric and radiobiological indices showed significantly different results. The modulation restricted clinical

  15. Radiobiological evaluation of the influence of dwell time modulation restriction in HIPO optimized HDR prostate brachytherapy implants

    Directory of Open Access Journals (Sweden)

    Dimos Baltas

    2010-10-01

    Full Text Available Purpose: One of the issues that a planner is often facing in HDR brachytherapy is the selective existence of high dose volumes around some few dominating dwell positions. If there is no information available about its necessity (e.g. location of a GTV, then it is reasonable to investigate whether this can be avoided. This effect can be eliminated by limiting the free modulation of the dwell times. HIPO, an inverse treatment plan optimization algorithm, offers this option.In treatment plan optimization there are various methods that try to regularize the variation of dose non-uniformity using purely dosimetric measures. However, although these methods can help in finding a good dose distribution they do not provide any information regarding the expected treatment outcome as described by radiobiology based indices.Material and methods: The quality of 12 clinical HDR brachytherapy implants for prostate utilizing HIPO and modulation restriction (MR has been compared to alternative plans with HIPO and free modulation (without MR.All common dose-volume indices for the prostate and the organs at risk have been considered together with radiobiological measures. The clinical effectiveness of the different dose distributions was investigated by calculating the response probabilities of the tumors and organs-at-risk (OARs involved in these prostate cancer cases. The radiobiological models used are the Poisson and the relative seriality models. Furthermore, the complication-free tumor control probability, P+ and the biologically effective uniform dose (D = were used for treatment plan evaluation and comparison.Results: Our results demonstrate that HIPO with a modulation restriction value of 0.1-0.2 delivers high quality plans which are practically equivalent to those achieved with free modulation regarding the clinically used dosimetric indices.In the comparison, many of the dosimetric and radiobiological indices showed significantly different results. The

  16. SU-E-T-459: Impact of Source Position and Traveling Time On HDR Skin Surface Applicator Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, J; Barker, C; Zaider, M; Cohen, G [Memorial Sloan Kettering Cancer Center, New York, NY (United States)

    2015-06-15

    Purpose: Observed dosimetric discrepancy between measured and treatment planning system (TPS) predicted values, during applicator commissioning, were traced to source position uncertainty in the applicator. We quantify the dosimetric impact of this geometric uncertainty, and of the source traveling time inside the applicator, and propose corrections for clinical use. Methods: We measured the dose profiles from the Varian Leipzig-style (horizontal) HDR skin applicator, using EBT3 film, photon diode, and optically stimulated luminescence dosimeter (OSLD) and three different GammaMed HDR afterloders. The dose profiles and depth dose of each aperture were measured at several depths (up to about 10 mm, depending on the dosimeter). The measured dose profiles were compared with Acuros calculated profiles in BrachyVision TPS. For the impact of the source position, EBT3 film measurements were performed with applicator, facing-down and facing-up orientations. The dose with and without source traveling was measured with diode detector using HDR timer and electrometer timer, respectively. Results: Depth doses measured using the three dosimeters were in good agreement, but were consistently higher than the Acuros dose calculations. Measurements with the applicator facing-up were significantly lower than those in the facing-down position with maximum difference of about 18% at the surface, due to source sag inside the applicator. Based on the inverse-square law, the effective source sag was evaluated to be about 0.5 mm from the planned position. The additional dose from the source traveling was about 2.8% for 30 seconds with 10 Ci source, decreasing with increased dwelling time and decreased source activity. Conclusion: Due to the short source-to-surface distance of the applicator, the small source sag inside the applicator has significant dosimetric impact, which should be considered before the clinical use of the applicator. Investigation of the effect for other applicators

  17. An integrated system for clinical treatment verification of HDR prostate brachytherapy combining source tracking with pretreatment imaging.

    Science.gov (United States)

    Smith, Ryan L; Hanlon, Max; Panettieri, Vanessa; Millar, Jeremy L; Matheson, Bronwyn; Haworth, Annette; Franich, Rick D

    2017-09-22

    High-dose-rate (HDR) prostate brachytherapy treatment is usually delivered in one or a few large dose fractions. Poor execution of a planned treatment could have significant clinical impact, as high doses are delivered in seconds, and mistakes in an individual fraction cannot be easily rectified. Given that most potential errors in HDR brachytherapy ultimately lead to a geographical miss, a more direct approach to verification of correct treatment delivery is to directly monitor the position of the source throughout the treatment. In this work, we report on the clinical implementation of our treatment verification system that uniquely combines the 2D source-tracking capability with 2D pretreatment imaging, using a single flat panel detector (FPD). The clinical brachytherapy treatment couch was modified to allow integration of the FPD into the couch. This enabled the patient to be set up in the brachytherapy bunker in a position that closely matched that at treatment planning imaging. An anteroposterior image was acquired of the patient immediately before treatment delivery and was assessed by the Radiation Oncologist online, to reestablish the positions of the catheters relative to the prostate. Assessment of catheter positions was performed in the left-right and superior-inferior directions along the entire catheter length and throughout the treatment volume. Source tracking was then performed during treatment delivery, and the measured position of the source dwells were directly compared to the treatment plan for verification. The treatment verification system was integrated into the clinical environment without significant change to workflow. Two patient cases are presented in this work to provide clinical examples of this system, which is now in routine use for all patient treatments in our clinic. The catheter positions were visualized relative to the prostate, immediately before treatment delivery. For one of the patient cases presented in this work, they

  18. Adaptive error detection for HDR/PDR brachytherapy: Guidance for decision making during real-time in vivo point dosimetry

    DEFF Research Database (Denmark)

    Kertzscher Schwencke, Gustavo Adolfo Vladimir; Andersen, Claus E.; Tanderup, Kari

    2014-01-01

    Purpose:This study presents an adaptive error detection algorithm (AEDA) for real-timein vivo point dosimetry during high dose rate (HDR) or pulsed dose rate (PDR) brachytherapy (BT) where the error identification, in contrast to existing approaches, does not depend on an a priori reconstruction...... of the dosimeter position. Instead, the treatment is judged based on dose rate comparisons between measurements and calculations of the most viable dosimeter position provided by the AEDA in a data driven approach. As a result, the AEDA compensates for false error cases related to systematic effects...... of the dosimeter position reconstruction. Given its nearly exclusive dependence on stable dosimeter positioning, the AEDA allows for a substantially simplified and time efficient real-time in vivo BT dosimetry implementation. Methods:In the event of a measured potential treatment error, the AEDA proposes the most...

  19. On the use of HDR Co60 source with the MammoSite(®) Radiation Therapy System.

    Science.gov (United States)

    Baltas, D; Lymperopoulou, G; Zamboglou, N

    2008-12-01

    This work summarizes Monte Carlo results in order to evaluate the potential of using HDR Co60 sources in accelerated partial breast irradiation (APBI) with the MammoSite(®) applicator. Simulations have been performed using the MCNP5 Monte Carlo Code, in simple geometries comprised of two concentric spheres; the internal consisting of selected concentrations, C, of a radiographic contrast solution in water (Omnipaque 300(™) ) to simulate the MammoSite balloon and the external consisting of water to simulate surrounding tissue. The magnitude of the perturbation of delivered dose due to the radiographic contrast medium used in the MammoSite(®) applicator is calculated. At the very close vicinity of the balloon surface, a dose build-up region is observed, which leads to a dose overestimation by the treatment planning system (TPS) which depends on Omnipaque(™) 300 solution concentration (and is in order of 2.3%, 3.0%, and 4.5%, respectively, at 1 mm away from the balloon - water interface, for C=10%, 15%, and 20%). However, dose overestimation by the TPS is minimal for points lying at the prescription distance (d=1 cm) or beyond, for all simulated concentrations and radii of MammoSite(®) balloon. An analytical estimation of the integral dose outside the CTV in the simple geometries simulated shows that dose to the breast for MammoSite(®) applications is expected to be comparable using HDR Co60 and Ir192 sources, and higher than that for Yb169. The higher enegies of Co60 sources result to approximately twice radiation protection requirements as compared to Ir169 sources. However, they allow for more accurate dosimetry calculation with currently used treatment planning algorithms for Co60 sources, compared to Ir169. © 2008 American Association of Physicists in Medicine.

  20. Dosimetric evaluation of PLATO and Oncentra treatment planning systems for High Dose Rate (HDR) brachytherapy gynecological treatments

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Hardev; De La Fuente Herman, Tania; Showalter, Barry; Thompson, Spencer J.; Syzek, Elizabeth J.; Herman, Terence; Ahmad, Salahuddin [Department of Radiation Oncology, Peggy and Charles Stephenson Oklahoma Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104 (United States)

    2012-10-23

    This study compares the dosimetric differences in HDR brachytherapy treatment plans calculated with Nucletron's PLATO and Oncentra MasterPlan treatment planning systems (TPS). Ten patients (1 T1b, 1 T2a, 6 T2b, 2 T4) having cervical carcinoma, median age of 43.5 years (range, 34-79 years) treated with tandem and ring applicator in our institution were selected retrospectively for this study. For both Plato and Oncentra TPS, the same orthogonal films anterior-posterior (AP) and lateral were used to manually draw the prescription and anatomical points using definitions from the Manchester system and recommendations from the ICRU report 38. Data input for PLATO was done using a digitizer and Epson Expression 10000XL scanner was used for Oncentra where the points were selected on the images in the screen. The prescription doses for these patients were 30 Gy to points right A (RA) and left A (LA) delivered in 5 fractions with Ir-192 HDR source. Two arrangements: one dwell position and two dwell positions on the tandem were used for dose calculation. The doses to the patient points right B (RB) and left B (LB), and to the organs at risk (OAR), bladder and rectum for each patient were calculated. The mean dose and the mean percentage difference in dose calculated by the two treatment planning systems were compared. Paired t-tests were used for statistical analysis. No significant differences in mean RB, LB, bladder and rectum doses were found with p-values > 0.14. The mean percent difference of doses in RB, LB, bladder and rectum are found to be less than 2.2%, 1.8%, 1.3% and 2.2%, respectively. Dose calculations based on the two different treatment planning systems were found to be consistent and the treatment plans can be made with either system in our department without any concern.

  1. SU-F-T-24: Impact of Source Position and Dose Distribution Due to Curvature of HDR Transfer Tubes

    Energy Technology Data Exchange (ETDEWEB)

    Khan, A; Yue, N [Rutgers University, New Brunswick, NJ (United States)

    2016-06-15

    Purpose: Brachytherapy is a highly targeted from of radiotherapy. While this may lead to ideal dose distributions on the treatment planning system, a small error in source location can lead to change in the dose distribution. The purpose of this study is to quantify the impact on source position error due to curvature of the transfer tubes and the impact this may have on the dose distribution. Methods: Since the source travels along the midline of the tube, an estimate of the positioning error for various angles of curvature was determined using geometric properties of the tube. Based on the range of values a specific shift was chosen to alter the treatment plans for a number of cervical cancer patients who had undergone HDR brachytherapy boost using tandem and ovoids. Impact of dose to target and organs at risk were determined and checked against guidelines outlined by radiation oncologist. Results: The estimate of the positioning error was 2mm short of the expected position (the curved tube can only cause the source to not reach as far as with a flat tube). Quantitative impact on the dose distribution is still in the process of being analyzed. Conclusion: The accepted positioning tolerance for the source position of a HDR brachytherapy unit is plus or minus 1mm. If there is an additional 2mm discrepancy due to tube curvature, this can result in a source being 1mm to 3mm short of the expected location. While we do always attempt to keep the tubes straight, in some cases such as with tandem and ovoids, the tandem connector does not extend as far out from the patient so the ovoid tubes always contain some degree of curvature. The dose impact of this may be significant.

  2. SU-G-201-07: Dosimetric Verification of a 3D Printed HDR Skin Brachytherapy Applicator

    Energy Technology Data Exchange (ETDEWEB)

    Rasmussen, K; Stanley, D; Eng, T; Kirby, N; Gutierrez, A; Stathakis, S; Papanikolaou, N [University of Texas HSC SA, San Antonio, TX (United States); Baumgarten, A; Pelletier, C; Jung, J; Feng, Y; Huang, Z; Ju, A [East Carolina University, Greenville, NC (United States); Corbett, M [Greenville Health System, Greenville, SC (United States)

    2016-06-15

    Purpose: The use of radiation as a treatment modality for skin cancer has increased significantly over the last decade with standardized applicators. Utilizing 3D printing, the ability to make applicators specifically designed for each patient’s anatomy has become economically feasible. With this in mind it was the aim of this study to determine the dosimetric accuracy of a 3-D printed HDR brachytherapy applicator for the skin. Methods: A CT reference image was used to generate a custom applicator based on an anthropomorphic head and neck phantom. To create the applicator a 1cm expansion anteriorly with 0.5cmX0.5cm trenches on the outer surface that were spaced 1cm sup-inf to accommodate standard 6F flexible catheters. The applicator was printed using PLA material using a printrbot simple printer. A treatment plan optimized to deliver a clinically representative volume was created in Oncentra and delivered with a nucletron afterloader. Measurements were made using TLDs and EBT3 gafchromic film that were placed between the applicator and the phantom’s forehead. An additional piece of film was also used to qualitatively asses the dose distribution in the transverse plane. Using a standard vaginal cylinder and bolus, a standardized curve correlating TLD and film exposure-to-radiation dose was established by irradiating film to known doses (200,500,700 cGy) at a 3.5 cm radius distance. Results: Evaluated TLDs showed the absolute dose delivered to the skin surface using the 3-D printed bolus was 615cGy±6%, with a mean predicted TPS value in the measured area of 617.5±7%. Additionally, planar dose distributions had good qualitative agreement with calculated TPS isodoses. Conclusion: This work demonstrates patient specific 3-D printed HDR brachytherapy applicators for skin cancer treatments are practical and accurate in TPS calculations but additional measurements are needed to verify additional sites and dose at depth.

  3. An intrauterine ultrasound applicator for targeted delivery of thermal therapy in conjunction with HDR brachytherapy to the cervix

    Science.gov (United States)

    Wootton, Jeffery H.; Juang, Titania; Pouliot, Jean; Hsu, I.-Chow Joe; Diederich, Chris J.

    2009-02-01

    An intracavitary hyperthermia applicator for targeted heat delivery to the cervix was developed based on a linear array of sectored tubular ultrasound transducers that provides truly 3-D heating control (angular and along the length). A central conduit can incorporate an HDR source for sequential or simultaneous delivery of heat and radiation. Hyperthermia treatment volumes were determined from brachytherapy treatment planning data and used as a basis for biothermal simulations analyzing the effects of device parameters, tissue properties, and catheter materials on heating patterns. Devices were then developed with 1-3 elements at 6.5-8 MHz with 90-180° sectors and a 15-35 mm heating length, housed within a 6-mm diameter water-cooled PET catheter. Directional heating from sectored transducers could extend lateral penetration of therapeutic heating (41°C) >2 cm while maintaining rectum and bladder temperatures within 12 mm below thermal damage thresholds. Imaging artifacts were evaluated with standard CT, cone beam CT, and MR images. MR thermal imaging was used to demonstrate shaping of heating profiles in axial and coronal slices with artifact <2 mm from the device. The impact of the high-Z applicator materials on the HDR dose distribution was assessed using a well-type ionization chamber and was found to be less than 6% attenuation, which can readily be accounted for with treatment planning software. The intrauterine ultrasound device has demonstrated potential for 3-D conformal heating of clinical tumors in the delivery of targeted hyperthermia in conjunction with brachytherapy to the cervix.

  4. TU-AB-201-04: Optimizing the Number of Catheter Implants and Their Tracks for Prostate HDR Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Riofrio, D; Luan, S [University of New Mexico, Albuquerque, New Mexico (United States); Zhou, J [William Beaumont Hospital, Royal Oak, MI (United States); Ma, L [UCSF Comprehensive Cancer Center, San Francisco, CA (United States)

    2015-06-15

    Purpose: In prostate HDR brachytherapy, interstitial implants are placed manually on the fly. The aim for this research is to develop a computer algorithm to find optimal and reliable implant trajectories using minimal number of implants. Methods: Our new algorithm mainly uses these key ideas: (1) positive charged static particles are uniformly placed on the surface of prostate and critical structures such as urethra, bladder, and rectum. (2) Positive charged kinetic particles are placed at a cross-section of the prostate with an initial velocity parallel to the principal implant direction. (3) The kinetic particles move through the prostate, interacting with each other, spreading out, while staying away from the prostate surface and critical structures. The initial velocity ensures that the trajectories observe the curvature constraints of typical implant procedures. (4) The finial trajectories of kinetic particles are smoothed using a third-degree polynomial regression, which become the implant trajectories. (5) The dwelling times and final dose distribution are calculated using least-distance programming. Results: (1) We experimented with previously treated cases. Our plan achieves all prescription goals while reducing the number of implants by 41%! Our plan also has less uniform target dose, which implies a higher dose is delivered to the prostate. (2) We expect future implant procedures will be performed under the guidance of such pre-calculated trajectories. To assess the applicability, we randomly perturb the tracks to mimic the manual implant errors. Our studies showed the impact of these perturbations are negligible, which is compensated by the least distance programming. Conclusions: We developed a new inverse planning system for prostate HDR therapy that can find optimal implant trajectories while minimizing the number of implants. For future work, we plan to integrate our new inverse planning system with an existing needle tracking system.

  5. Single institutional retrospective analysis: treatment of choroidal melanomas with cobalt-60 brachytherapy Análise retrospectiva uni-institucional: tratamento de melanomas de coróide com braquiterapia utilizando cobalto-60

    Directory of Open Access Journals (Sweden)

    Antônio Cássio Assis Pellizzon

    2004-06-01

    Full Text Available PURPOSE: To evaluate the outcome of patients with choroidal melanoma treated with conservative therapy with brachytherapy (episcleral Co-60 plaque therapy at the "Hospital do Cancer" São Paulo, Brazil. METHODS: We evaluated 102 patients consecutively treated from January, 1999 to June, 1999. Median age, maximum tumor base diameter and apex size were 55.5 years, 9.75 mm and 5 mm, respectively. Doses at the base of the tumor, including 1 mm of sclera, ranged from 157 to 487 Gy (median 284.5 Gy and to the apex from 37 to 220 Gy (median 106 Gy. RESULTS: The crude eye preservation rate with conservative therapy alone was 78.5%. Five-year overall actuarial survival rate was 92.2% and eye conservation rate was 78%. Side effects were mostly an uncomplicated retinopathy in 39/102 patients (38.2%; macular degeneration or scarring led to poor central vision in 31/102 patients (30.3% of cases. CONCLUSION: Our experience with cobalt-60 plaque brachytherapy achieved a satisfactory rate of local tumor control, despite the oversized base diameters of treated tumors.OBJETIVOS: Para avaliar o resultado de tratamento pacientes portadores de melanoma de coróide tratados com braquiterapia (placas episclerais de Co-60 no Hospital do Câncer, São Paulo, Brasil. MÉTODOS: Foram avaliados 108 pacientes tratados consecutivamente de janeiro de 1995 a junho de 1999, com idade mediana de 55,5 anos, diâmetro da base do tumor e altura máximos 9,75 mm e 5 mm, respectivamente. As doses na base do tumor, incluindo 1 mm de esclera variaram de 157 a 487 Gy (mediana 284,5 Gy e para o ápice de 37 até 220 Gy (mediana 106 Gy. RESULTADOS: A taxa de preservação ocular foi 78,5%, com sobrevida atuarial global em cinco anos, e a taxa de conservação ocular atuarial foram 92,2% e 78%, respectivamente. Os principais efeitos colaterais relacionados ao tratamento foram retinopatia em 39/102 (38,2% pacientes e degeneração macular, levando a déficit visual central em 31/102 (30

  6. SU-F-T-28: Evaluation of BEBIG HDR Co-60 After-Loading System for Skin Cancer Treatment Using Conical Surface Applicator

    Energy Technology Data Exchange (ETDEWEB)

    Safigholi, H; Soliman, A; Song, W Y [Department of Medical Physics, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON (Canada); Meigooni, A S [Department of Radiation Therapy, Comprehensive Cancer Center of Nevada, Las Vegas, NV (United States); Han, D [Departemt of Radiation Oncology, University of California San Francisco, San Francisco, CA (United States)

    2016-06-15

    Purpose: To evaluate the possibility of utilizing the BEBIG HDR 60Co remote after-loading system for malignant skin surface treatment using Monte Carlo (MC) simulation technique. Methods: First TG-43 parameters of BEBIG-Co-60 and Nucletron Ir-192-mHDR-V2 brachytherapy sources were simulated using MCNP6 code to benchmark the sources against the literature. Second a conical tungsten-alloy with 3-cm diameter of Planning-Target-Volume (PTV) at surface for use with a single stepping HDR source is designed. The HDR source is modeled parallel to treatment plane at the center of the conical applicator with a source surface distance (SSD) of 1.5-cm and a removable plastic end-cap with a 1-mm thickness. Third, MC calculated dose distributions from HDR Co-60 for conical surface applicator were compared with the simulated data using HDR Ir-192 source. The initial calculations were made with the same conical surface applicator (standard-applicator) dimensions as the ones used with the Ir-192 system. Fourth, the applicator wall-thickness for the Co-60 system was increased (doubled) to diminish leakage dose to levels received when using the Ir-192 system. With this geometry, percentage depth dose (PDD), and relative 2D-dose profiles in transverse/coronal planes were normalized at 3-mm prescription-depth evaluated along the central axis. Results: PDD for Ir-192 and Co-60 were similar with standard and thick-walled applicator. 2D-relative dose distribution of Co-60, inside the standard-conical-applicator, generated higher penumbra (7.6%). For thick-walled applicator, it created smaller penumbra (<4%) compared to Ir-192 source in the standard-conicalapplicator. Dose leakage outside of thick-walled applicator with Co-60 source was approximately equal (≤3%) with standard applicator using Ir-192 source. Conclusion: Skin cancer treatment with equal quality can be performed with Co-60 source and thick-walled conical applicators instead of Ir-192 with standard applicators. These conical

  7. Identifying afterloading PDR and HDR brachytherapy errors using real-time fiber-coupled Al2O3:C dosimetry and a novel statistical error decision criterion

    DEFF Research Database (Denmark)

    Kertzscher, Gustavo; Andersen, Claus Erik; Siebert, Frank-André

    2011-01-01

    Background and purposeThe feasibility of a real-time in vivo dosimeter to detect errors has previously been demonstrated. The purpose of this study was to: (1) quantify the sensitivity of the dosimeter to detect imposed treatment errors under well controlled and clinically relevant experimental...... conditions, and (2) test a new statistical error decision concept based on full uncertainty analysis. Materials and methodsPhantom studies of two gynecological cancer PDR and one prostate cancer HDR patient treatment plans were performed using tandem ring applicators or interstitial needles. Imposed...... identified displacements ⩾5mm. ConclusionThis phantom study demonstrates that Al2O3:C real-time dosimetry can identify applicator displacements ⩾5mm and interchanged guide tube errors during PDR and HDR brachytherapy. The study demonstrates the shortcoming of a constant error criterion and the advantage...

  8. Analysis of risk assessment of brachytherapy from the radiotherapy services of the metropolitan region of Rio de Janeiro, RJ, Brazil; Analise da percepcao de risco da braquiterapia dos servicos de radioterapia da regiao metropolitana do Rio de Janeiro

    Energy Technology Data Exchange (ETDEWEB)

    Burgos, Adam de Freitas; Paiva, Eduardo de, E-mail: adam@bolsista.ird.gov.br, E-mail: epaiva@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ),Rio de Janeiro, RJ (Brazil); Souza, Roberto Salomon de, E-mail: salomon@inca.gov.br [Instituto Nacional de Cancer (PQRT/INCA), Rio de Janeiro, RJ (Brazil). Programa de Qualidade em Radioterapia

    2014-07-01

    Currently there are few applications on the risk analysis procedures related to radiotherapy, mainly in the practice of brachytherapy. The objective of this study was to analyze the perception of risk levels, present in the practice of high dose rate brachytherapy (HDR), using a form based on the concept of the risk matrix and a database (SEVRRA) containing information about the processes related to routine brachytherapy. A form containing information regarding the brachytherapy procedure HDR and an attachment indicating how to complete it properly was delivered to a medical physicist of each service/institution. The reference value for the risk levels found, considered acceptable for all performed analyzes, was set at a percentage limit of 33% (assuming a failure in each 3 existing processes). The results showed that the overall risk analysis showed a value for average percentage of prioritized risk of 18% below the recommended range. About the analyzed groups, the higher average percentage of relative risk was found less than 12% of the recommended range, associated with the group of patients. On existing steps, the highest average percentage of relative risk was found less than 1% of the recommended range, associated with stage records and treatment planning. This study showed that although this procedure does not have a large history of accidents, still poses risks considerable that must be managed with great accuracy and immediate action to an effective decrease these risk percentages.

  9. Cosmetic changes following surgery and accelerated partial breast irradiation using HDR interstitial brachytherapy : Evaluation by a multidisciplinary/multigender committee.

    Science.gov (United States)

    Soror, Tamer; Kovács, György; Seibold, Nina; Melchert, Corinna; Baumann, Kristin; Wenzel, Eike; Stojanovic-Rundic, Suzana

    2017-05-01

    Patients with early-stage breast cancer can benefit from adjuvant accelerated partial breast irradiation (APBI) following breast-conserving surgery (BCS). This work reports on cosmetic results following APBI using multicatheter high-dose-rate interstitial brachytherapy (HDR-IBT). Between 2006 and 2014, 114 patients received adjuvant APBI using multicatheter HDR-IBT. For each patient, two photographs were analyzed: the first was taken after surgery (baseline image) and the second at the last follow-up visit. Cosmesis was assessed by a multigender multidisciplinary team using the Harvard Breast Cosmesis Scale. Dose-volume histogram (DVH) parameters and the observed cosmetic results were investigated for potential correlations. The median follow-up period was 3.5 years (range 0.6-8.5 years). The final cosmetic scores were 30% excellent, 52% good, 14.5% fair, and 3.5% poor. Comparing the baseline and follow-up photographs, 59.6% of patients had the same score, 36% had a better final score, and 4.4% had a worse final score. Only lower target dose nonuniformity ratio (DNR) values (0.3 vs. 0.26; p = 0.009) were significantly associated with improved cosmetic outcome vs. same/worse cosmesis. APBI using multicatheter HDR-IBT adjuvant to BCS results in favorable final cosmesis. Deterioration in breast cosmesis occurs in less than 5% of patients. The final breast cosmetic outcome in patients treated with BCS and APBI using multicatheter HDR-IBT is influenced primarily by the cosmetic result of the surgery. A lower DNR value is significantly associated with a better cosmetic outcome.

  10. SU-E-T-785: Using Systems Engineering to Design HDR Skin Treatment Operation for Small Lesions to Enhance Patient Safety

    Energy Technology Data Exchange (ETDEWEB)

    Saw, C; Baikadi, M; Peters, C; Brereton, H [Northeast Radiation Oncology Centers, Harrisburg, PA (United States)

    2015-06-15

    Purpose: Using systems engineering to design HDR skin treatment operation for small lesions using shielded applicators to enhance patient safety. Methods: Systems engineering is an interdisciplinary field that offers formal methodologies to study, design, implement, and manage complex engineering systems as a whole over their life-cycles. The methodologies deal with human work-processes, coordination of different team, optimization, and risk management. The V-model of systems engineering emphasize two streams, the specification and the testing streams. The specification stream consists of user requirements, functional requirements, and design specifications while the testing on installation, operational, and performance specifications. In implementing system engineering to this project, the user and functional requirements are (a) HDR unit parameters be downloaded from the treatment planning system, (b) dwell times and positions be generated by treatment planning system, (c) source decay be computer calculated, (d) a double-check system of treatment parameters to comply with the NRC regulation. These requirements are intended to reduce human intervention to improve patient safety. Results: A formal investigation indicated that the user requirements can be satisfied. The treatment operation consists of using the treatment planning system to generate a pseudo plan that is adjusted for different shielded applicators to compute the dwell times. The dwell positions, channel numbers, and the dwell times are verified by the medical physicist and downloaded into the HDR unit. The decayed source strength is transferred to a spreadsheet that computes the dwell times based on the type of applicators and prescribed dose used. Prior to treatment, the source strength, dwell times, dwell positions, and channel numbers are double-checked by the radiation oncologist. No dosimetric parameters are manually calculated. Conclusion: Systems engineering provides methodologies to

  11. SU-F-T-65: AutomaticTreatment Planning for High-Dose Rate (HDR) Brachytherapy with a VaginalCylinder Applicator

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Y; Tan, J; Jiang, S; Albuquerque, K; Jia, X [UT Southwestern Medical Center, Dallas, TX (United States)

    2016-06-15

    Purpose: High dose rate (HDR) brachytherapy treatment planning is conventionally performed in a manual fashion. Yet it is highly desirable to perform computerized automated planning to improve treatment planning efficiency, eliminate human errors, and reduce plan quality variation. The goal of this research is to develop an automatic treatment planning tool for HDR brachytherapy with a cylinder applicator for vaginal cancer. Methods: After inserting the cylinder applicator into the patient, a CT scan was acquired and was loaded to an in-house developed treatment planning software. The cylinder applicator was automatically segmented using image-processing techniques. CTV was generated based on user-specified treatment depth and length. Locations of relevant points (apex point, prescription point, and vaginal surface point), central applicator channel coordinates, and dwell positions were determined according to their geometric relations with the applicator. Dwell time was computed through an inverse optimization process. The planning information was written into DICOM-RT plan and structure files to transfer the automatically generated plan to a commercial treatment planning system for plan verification and delivery. Results: We have tested the system retrospectively in nine patients treated with vaginal cylinder applicator. These cases were selected with different treatment prescriptions, lengths, depths, and cylinder diameters to represent a large patient population. Our system was able to generate treatment plans for these cases with clinically acceptable quality. Computation time varied from 3–6 min. Conclusion: We have developed a system to perform automated treatment planning for HDR brachytherapy with a cylinder applicator. Such a novel system has greatly improved treatment planning efficiency and reduced plan quality variation. It also served as a testbed to demonstrate the feasibility of automatic HDR treatment planning for more complicated cases.

  12. A Pilot Study of Catheter-Based Ultrasound Hyperthermia with HDR Brachytherapy for Treatment of Locally Advanced Cancer of the Prostate and Cervix

    Science.gov (United States)

    Diederich, Chris J.; Wootton, Jeff; Prakash, Punit; Salgaonkar, Vasant; Juang, Titania; Scott, Serena; Chen, Xin; Cunha, Adam; Pouliot, Jean; Hsu, I. C.

    2011-09-01

    Interstitial and endocavity ultrasound devices have been developed specifically for applying hyperthermia within temporary HDR brachytherapy implants during radiation therapy. Catheter-based ultrasound applicators are capable of 3D spatial control of heating in both angle and length of the devices, with enhanced radial penetration of heating compared to other hyperthermia technologies. A pilot study of the combination of catheter based ultrasound with HDR brachytherapy for locally advanced prostate and cervical cancer has been initiated, and preliminary results of the performance and heating distributions are reported herein. The treatment delivery platform consists of a 32 channel RF amplifier and a 48 channel thermocouple monitoring system. Controlling software can monitor and regulate frequency and power to each transducer section as required during the procedure. Interstitial applicators consist of multiple transducer sections of 2-4 cm length×180 deg and 3-4 cm×360 deg. heating patterns to be inserted in specific placed 13g implant catheters. The endocavity device, designed to be inserted within a 6 mm OD plastic tandem catheter within the cervix, consists of 2-3 transducers x dual 180 or 360 deg sectors. 3D temperature based treatment planning and optimization is dovetailed to the HDR optimization based planning to best configure and position the applicators within the catheters, and to determine optimal base power levels to each transducer section. To date we have treated eight cervix implants and four prostate implants. 100% of treatments achieved a goal of >60 min duration, with therapeutic temperatures achieved in all cases. Thermal dosimetry within the hyperthermia target volume (HTV) and clinical target volume (CTV) are reported. Catheter-based ultrasound hyperthermia with HDR appears feasible with therapeutic temperature coverage of the target volume within the prostate or cervix while sparing surrounding more sensitive regions.

  13. Implant strategies for endocervical and interstitial ultrasound hyperthermia adjunct to HDR brachytherapy for the treatment of cervical cancer

    Energy Technology Data Exchange (ETDEWEB)

    Wootton, Jeffery H; Prakash, Punit; Hsu, I-Chow Joe; Diederich, Chris J, E-mail: CDiederich@radonc.ucsf.edu [Department of Radiation Oncology, University of California, San Francisco, CA 94115 (United States)

    2011-07-07

    Catheter-based ultrasound devices provide a method to deliver 3D conformable heating integrated with HDR brachytherapy delivery. Theoretical characterization of heating patterns was performed to identify implant strategies for these devices which can best be used to apply hyperthermia to cervical cancer. A constrained optimization-based hyperthermia treatment planning platform was used for the analysis. The proportion of tissue {>=}41 deg. C in a hyperthermia treatment volume was maximized with constraints T{sub max} {<=} 47 deg. C, T{sub rectum} {<=} 41.5 deg. C, and T{sub bladder} {<=} 42.5 deg. C. Hyperthermia treatment was modeled for generalized implant configurations and complex configurations from a database of patients (n = 14) treated with HDR brachytherapy. Various combinations of endocervical (360{sup 0} or 2 x 180{sup 0} output; 6 mm OD) and interstitial (180{sup 0}, 270{sup 0}, or 360{sup 0} output; 2.4 mm OD) applicators within catheter locations from brachytherapy implants were modeled, with perfusion constant (1 or 3 kg m{sup -3} s{sup -1}) or varying with location or temperature. Device positioning, sectoring, active length and aiming were empirically optimized to maximize thermal coverage. Conformable heating of appreciable volumes (>200 cm{sup 3}) is possible using multiple sectored interstitial and endocervical ultrasound devices. The endocervical device can heat >41 deg. C to 4.6 cm diameter compared to 3.6 cm for the interstitial. Sectored applicators afford tight control of heating that is robust to perfusion changes in most regularly spaced configurations. T{sub 90} in example patient cases was 40.5-42.7 deg. C (1.9-39.6 EM{sub 43deg.C}) at 1 kg m{sup -3} s{sup -1} with 10/14 patients {>=}41 deg. C. Guidelines are presented for positioning of implant catheters during the initial surgery, selection of ultrasound applicator configurations, and tailored power schemes for achieving T{sub 90} {>=} 41 deg. C in clinically practical implant

  14. Adaptive error detection for HDR/PDR brachytherapy: guidance for decision making during real-time in vivo point dosimetry.

    Science.gov (United States)

    Kertzscher, Gustavo; Andersen, Claus E; Tanderup, Kari

    2014-05-01

    This study presents an adaptive error detection algorithm (AEDA) for real-time in vivo point dosimetry during high dose rate (HDR) or pulsed dose rate (PDR) brachytherapy (BT) where the error identification, in contrast to existing approaches, does not depend on an a priori reconstruction of the dosimeter position. Instead, the treatment is judged based on dose rate comparisons between measurements and calculations of the most viable dosimeter position provided by the AEDA in a data driven approach. As a result, the AEDA compensates for false error cases related to systematic effects of the dosimeter position reconstruction. Given its nearly exclusive dependence on stable dosimeter positioning, the AEDA allows for a substantially simplified and time efficient real-time in vivo BT dosimetry implementation. In the event of a measured potential treatment error, the AEDA proposes the most viable dosimeter position out of alternatives to the original reconstruction by means of a data driven matching procedure between dose rate distributions. If measured dose rates do not differ significantly from the most viable alternative, the initial error indication may be attributed to a mispositioned or misreconstructed dosimeter (false error). However, if the error declaration persists, no viable dosimeter position can be found to explain the error, hence the discrepancy is more likely to originate from a misplaced or misreconstructed source applicator or from erroneously connected source guide tubes (true error). The AEDA applied on two in vivo dosimetry implementations for pulsed dose rate BT demonstrated that the AEDA correctly described effects responsible for initial error indications. The AEDA was able to correctly identify the major part of all permutations of simulated guide tube swap errors and simulated shifts of individual needles from the original reconstruction. Unidentified errors corresponded to scenarios where the dosimeter position was sufficiently symmetric with

  15. Adaptive error detection for HDR/PDR brachytherapy: Guidance for decision making during real-time in vivo point dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Kertzscher, Gustavo, E-mail: guke@dtu.dk; Andersen, Claus E., E-mail: clan@dtu.dk [Centre for Nuclear Technologies, Technical University of Denmark, DTU Nutech, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Tanderup, Kari, E-mail: karitand@rm.dk [Department of Oncology, Aarhus University Hospital and Institute of Clinical Medicine, Aarhus University, Norrebrogade 44, DK-8000 Aarhus (Denmark)

    2014-05-15

    Purpose: This study presents an adaptive error detection algorithm (AEDA) for real-timein vivo point dosimetry during high dose rate (HDR) or pulsed dose rate (PDR) brachytherapy (BT) where the error identification, in contrast to existing approaches, does not depend on an a priori reconstruction of the dosimeter position. Instead, the treatment is judged based on dose rate comparisons between measurements and calculations of the most viable dosimeter position provided by the AEDA in a data driven approach. As a result, the AEDA compensates for false error cases related to systematic effects of the dosimeter position reconstruction. Given its nearly exclusive dependence on stable dosimeter positioning, the AEDA allows for a substantially simplified and time efficient real-time in vivo BT dosimetry implementation. Methods: In the event of a measured potential treatment error, the AEDA proposes the most viable dosimeter position out of alternatives to the original reconstruction by means of a data driven matching procedure between dose rate distributions. If measured dose rates do not differ significantly from the most viable alternative, the initial error indication may be attributed to a mispositioned or misreconstructed dosimeter (false error). However, if the error declaration persists, no viable dosimeter position can be found to explain the error, hence the discrepancy is more likely to originate from a misplaced or misreconstructed source applicator or from erroneously connected source guide tubes (true error). Results: The AEDA applied on twoin vivo dosimetry implementations for pulsed dose rate BT demonstrated that the AEDA correctly described effects responsible for initial error indications. The AEDA was able to correctly identify the major part of all permutations of simulated guide tube swap errors and simulated shifts of individual needles from the original reconstruction. Unidentified errors corresponded to scenarios where the dosimeter position was

  16. SU-E-T-242: Design of a Novel Afterloader Clearance QA Device for Biliary HDR Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Mullins, JP; Deufel, CL [Mayo Clinic, Rochester, MN (United States)

    2015-06-15

    Purpose: Bile duct cancer affects 2–3 thousand people annually in the United States. Radiation therapy has been shown to double median survival, with combined external beam and intraluminal high dose-rate (HDR) brachytherapy being most effective. Endoscopic retrograde cholangiopancreatography (ERCP) biliary HDR, a less-invasive alternative to trans-hepatic brachytherapy, is delivered through a catheter that travels a tortuous path from nose to bile duct, requiring wire drive force and dexterity beyond typical afterloader performance specifications. Thus, specific afterloader quality assurance(QA) is recommended for this procedure. Our aim was to create a device and process for Varisource afterloader clearance QA with objectives that it be quantitative and can monitor afterloader performance over time, compare performance between two distinct afterloaders and potentially Result in a predictive nomogram for patient-specific clearance. Methods: Based on retrospective reconstruction of 20 ERCP patient anatomies, we designed a phantom to test afterloader ability to drive the source wire along an intended treatment path. The ability of the afterloader to fully extend the intended treatment path is a function of number and diameters of turns. We have determined experimentally that relative position of the turns does not impact performance. Results: Both patient and QA paths involve three common turns/loops: a large turn representing the stomach(10.8cm±2.0cm), an elliptical loop representing the duodenum(7.3cm±1.5cmx4.8cm±0.7cm), and a final turn at the end of the bile duct that may be tight for some patient-specific anatomies and absent in others(3.7cm±0.7cm, where present). Our phantom design uses anatomical average turn diameters for the stomach and duodenum then terminates in a turn of quantitatively selectable diameter. The smallest final turn diameter that an afterloader can pass is recorded as the QA parameter. Conclusion: With this device and QA process, we

  17. SU-F-P-42: “To Navigate, Or Not to Navigate: HDR BT in Recurrent Spine Lesions”

    Energy Technology Data Exchange (ETDEWEB)

    Voros, L; Cohen, G; Zaider, M; Yamada, Y [Memorial Sloan-Kettering Cancer Center, New York, NY (United States)

    2016-06-15

    Purpose: We compare the accuracy of HDR catheter placement for paraspinal lesions using O-arm CBCT imaging combined with StealthStation navigation and traditional fluoroscopically guided catheter placement. Methods: CT and MRI scans were acquired pre-treatment to outline the lesions and design treatment plans (pre-plans) to meet dosimetric constrains. The pre-planned catheter trajectories were transferred into the StealthStation Navigation system prior to the surgery. The StealthStation is an infra red (IR) optical navigation system used for guidance of surgical instruments. An intraoperative CBCT scan (O-arm) was acquired with reference IR optical fiducials anchored onto the patient and registered with the preplan image study to guide surgical instruments in relation to the patients’ anatomy and to place the brachytherapy catheters along the pre-planned trajectories. The final treatment plan was generated based on a 2nd intraoperative CBCT scan reflecting achieved implant geometry. The 2nd CBCT was later registered with the initial CT scan to compare the preplanned dwell positions with actual dwell positions (catheter placements). Similar workflow was used in placement of 8 catheters (1 patient) without navigation, but under fluoroscopy guidance in an interventional radiology suite. Results: A total of 18 catheters (3 patients) were placed using navigation assisted surgery. Average displacement of 0.66 cm (STD=0.37cm) was observed between the pre-plan source positions and actual source positions in the 3 dimensional space. This translates into an average 0.38 cm positioning error in one direction including registration errors, digitization errors, and the surgeons ability to follow the planned trajectory. In comparison, average displacement of non-navigated catheters was 0.50 cm (STD=0.22cm). Conclusion: Spinal lesion HDR brachytherapy planning is a difficult task. Catheter placement has a direct impact on target coverage and dose to critical structures. While

  18. Análises de protocolos de braquiterapia, por alta taxa de dose, do controle de qualidade de alguns serviços locais, baseados no TG40, TG56 e ARCAL XXX Analysis of the high dose rate brachytherapy protocols of quality assurance programs of some local services, based on TG40, TG56 and ARCAL XXX.

    Directory of Open Access Journals (Sweden)

    Carmen S. Guzmán Calcina

    2001-08-01

    Full Text Available A braquiterapia por alta taxa de dose está recebendo atenção considerável na maioria dos países. Por isso, nos serviços que utilizam este equipamento exige-se que o desenvolvimento de um programa de controle de qualidade seja cada vez mais rigoroso, para garantir não apenas a segurança aos pacientes, mas também aos operadores e demais envolvidos. Este trabalho tem por objetivos fazer um levantamento dos tipos de testes para um equipamento de braquiterapia por alta taxa de dose, propostos pelos protocolos oficiais publicados (TG40, TG56 e ARCAL XXX e avaliar os tipos de testes que atualmente são realizados por alguns serviços de radioterapia, comparando-os com aqueles apresentados nos protocolos citados. Das análises feitas, observou-se que: a quanto aos protocolos oficiais, o TG56 é mais completo que o TG40 e o ARCAL XXX; b quanto às instituições analisadas, estas em geral se basearam no TG56 para elaborar seus próprios protocolos, os quais demonstraram ter também concordância com os outros já citados. Nestes protocolos, a inexistência dos testes anuais foi notada, o que pode ser explicado por sua aparição nas freqüências trimestral e semestral. Do produto deste estudo são apresentadas tabelas dos tipos de testes com suas respectivas freqüências de utilização, das quais um protocolo pode ser inferido para auxiliar na implementação, pelo menos, dos tipos de testes de controle de qualidade básicos e indispensáveis para o equipamento, garantindo, assim, um tratamento adequado aos pacientes e uma melhor segurança ao pessoal envolvido e, conseqüentemente, assegurando a garantia de qualidade na braquiterapia por alta taxa de dose.High dose rate brachytherapy has been increasingly recognized in most countries, and radiotherapy services using this equipment are encouraged to have a very efficient quality assurance program to ensure protection for patients, workers and other personnel involved. The objective of this

  19. Development and implementation of a remote audit tool for high dose rate (HDR) Ir-192 brachytherapy using optically stimulated luminescence dosimetry.

    Science.gov (United States)

    Casey, Kevin E; Alvarez, Paola; Kry, Stephen F; Howell, Rebecca M; Lawyer, Ann; Followill, David

    2013-11-01

    The aim of this work was to create a mailable phantom with measurement accuracy suitable for Radiological Physics Center (RPC) audits of high dose-rate (HDR) brachytherapy sources at institutions participating in National Cancer Institute-funded cooperative clinical trials. Optically stimulated luminescence dosimeters (OSLDs) were chosen as the dosimeter to be used with the phantom. The authors designed and built an 8 × 8 × 10 cm(3) prototype phantom that had two slots capable of holding Al2O3:C OSLDs (nanoDots; Landauer, Glenwood, IL) and a single channel capable of accepting all (192)Ir HDR brachytherapy sources in current clinical use in the United States. The authors irradiated the phantom with Nucletron and Varian (192)Ir HDR sources in order to determine correction factors for linearity with dose and the combined effects of irradiation energy and phantom characteristics. The phantom was then sent to eight institutions which volunteered to perform trial remote audits. The linearity correction factor was kL = (-9.43 × 10(-5) × dose) + 1.009, where dose is in cGy, which differed from that determined by the RPC for the same batch of dosimeters using (60)Co irradiation. Separate block correction factors were determined for current versions of both Nucletron and Varian (192)Ir HDR sources and these vendor-specific correction factors differed by almost 2.6%. For the Nucletron source, the correction factor was 1.026 [95% confidence interval (CI) = 1.023-1.028], and for the Varian source, it was 1.000 (95% CI = 0.995-1.005). Variations in lateral source positioning up to 0.8 mm and distal∕proximal source positioning up to 10 mm had minimal effect on dose measurement accuracy. The overall dose measurement uncertainty of the system was estimated to be 2.4% and 2.5% for the Nucletron and Varian sources, respectively (95% CI). This uncertainty was sufficient to establish a ± 5% acceptance criterion for source strength audits under a formal RPC audit program. Trial

  20. Exploitation of secondary standard for calibration in units of Dw,1 cm and assessment of several HDR brachytherapy planning systems

    Science.gov (United States)

    Gabris, Frantisek; Zeman, Jozef; Valenta, Jiri; Selbach, Hans-Joachim

    2012-10-01

    A secondary standard of the BEV, calibrated at the PTB in terms of Dw,1 cm, was used for calibration of the well-type chamber-based measuring systems used in clinics. In addition to the calibration, we tried to employ it for assessment of treatment planning systems (TPS) used for each particular afterloader. The dose to water at 1 cm distance from the source position was calculated by the TPS, using reference data from the source producer certificate. The values were compared directly with the dose measured at the same distance from the source. The comparison has been carried out for GammaMed Plus and MicroSelectron HDR sources. Differences of secondary standard measurements and TPS calculations were lower than ±5%, which is below the achievable uncertainty of both dose measurement and dose determination by the TPS. Nevertheless, it is higher than generally accepted in the case of external beam radiotherapy. Additional direct measurements in terms of Dw,1 cm may improve the safety and reliability of patient treatment. Part of the EMRP JRP T02.J06 Project ‘Increasing Cancer Treatment Efficacy Using 3D Brachytherapy’.

  1. Class solution in inverse planned HDR prostate brachytherapy for dose escalation of DIL defined by combined MRI/MRSI

    Science.gov (United States)

    Kim, Yongbok; Hsu, I-Chow J.; Lessard, Etienne; Kurhanewicz, John; Noworolski, Susan Moyher; Pouliot, Jean

    2015-01-01

    Purpose To establish an inverse planning set of parameters (class solution) to boost dominant intra-prostatic lesion (DIL) defined by MRI/MRSI. Methods For 15 patients, DIL were contoured on CT or MR images and a class solution was developed to boost the DIL under the dosimetric requirements of the RTOG-0321 protocol. To determine the maximum attainable level of boost for each patient, 5 different levels were considered, at least 110%, 120%, 130%, 140% and 150% of the prescribed dose. The maximum attainable level was compared to the plan without boost using cumulative dose volume histogram (DVH). Results DIL dose escalation was feasible for 11/15 patients under the requirements. The planning target volume (PTV) dose was slightly increased, while the DIL dose was significantly increased without any violation of requirements. With slight adjustments of the dose constraint parameters, the dose escalation was feasible for 13/15 patients under requirements. Conclusion Using a class solution, a dose escalation of the MRI/MRSI defined DIL up to 150% while complying with RTOG dosimetric requirements is feasible. This HDR brachytherapy approach to dose escalation allows a significant dose increase to the tumor while maintaining an acceptable risk of complications. PMID:18083260

  2. Development of a program for calculation of second dose and securities in brachytherapy high dose rate; Elaboracion de un programa para el segundo calculo de la dosis y seguridades en braquiterapia de alta tasa de dosis

    Energy Technology Data Exchange (ETDEWEB)

    Esteve Sanchez, S.; Martinez Albaladejo, M.; Garcia Fuentes, J. D.; Bejar Navarro, M. J.; Capuz Suarez, B.; Moris de Pablos, R.; Colmenares Fernandez, R.

    2015-07-01

    We assessed the reliability of the program with 80 patients in the usual points of prescription of each pathology. The average error of the calculation points is less than 0.3% in 95% of cases, finding the major differences in the axes of the applicators (maximum error -0.798%). The program has proved effective previously testing him with erroneous dosimetry. Thanks to the implementation of this program is achieved by the calculation of the dose and part of the process of quality assurance program in a few minutes, highlighting the case of HDR prostate due to having a limited time. Having separate data sheet allows each institution to its protocols modify parameters. (Author)

  3. Calculated organ doses using Monte Carlo simulations in a reference male phantom undergoing HDR brachytherapy applied to localized prostate carcinoma.

    Science.gov (United States)

    Candela-Juan, Cristian; Perez-Calatayud, Jose; Ballester, Facundo; Rivard, Mark J

    2013-03-01

    The aim of this study was to obtain equivalent doses in radiosensitive organs (aside from the bladder and rectum) when applying high-dose-rate (HDR) brachytherapy to a localized prostate carcinoma using (60)Co or (192)Ir sources. These data are compared with results in a water phantom and with expected values in an infinite water medium. A comparison with reported values from proton therapy and intensity-modulated radiation therapy (IMRT) is also provided. Monte Carlo simulations in Geant4 were performed using a voxelized phantom described in International Commission on Radiological Protection (ICRP) Publication 110, which reproduces masses and shapes from an adult reference man defined in ICRP Publication 89. Point sources of (60)Co or (192)Ir with photon energy spectra corresponding to those exiting their capsules were placed in the center of the prostate, and equivalent doses per clinical absorbed dose in this target organ were obtained in several radiosensitive organs. Values were corrected to account for clinical circumstances with the source located at various positions with differing dwell times throughout the prostate. This was repeated for a homogeneous water phantom. For the nearest organs considered (bladder, rectum, testes, small intestine, and colon), equivalent doses given by (60)Co source were smaller (8%-19%) than from (192)Ir. However, as the distance increases, the more penetrating gamma rays produced by (60)Co deliver higher organ equivalent doses. The overall result is that effective dose per clinical absorbed dose from a (60)Co source (11.1 mSv/Gy) is lower than from a (192)Ir source (13.2 mSv/Gy). On the other hand, equivalent doses were the same in the tissue and the homogeneous water phantom for those soft tissues closer to the prostate than about 30 cm. As the distance increased, the differences of photoelectric effect in water and soft tissue, and appearance of other materials such as air, bone, or lungs, produced variations between both

  4. Calculated organ doses using Monte Carlo simulations in a reference male phantom undergoing HDR brachytherapy applied to localized prostate carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Candela-Juan, Cristian [Radioprotection Department, La Fe University and Polytechnic Hospital, Valencia 46026 (Spain); Perez-Calatayud, Jose [Radiotherapy Department, La Fe University and Polytechnic Hospital, Valencia 46026 (Spain); Ballester, Facundo [Department of Atomic, Molecular and Nuclear Physics, University of Valencia, Burjassot 46100 (Spain); Rivard, Mark J. [Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts 02111 (United States)

    2013-03-15

    Purpose: The aim of this study was to obtain equivalent doses in radiosensitive organs (aside from the bladder and rectum) when applying high-dose-rate (HDR) brachytherapy to a localized prostate carcinoma using {sup 60}Co or {sup 192}Ir sources. These data are compared with results in a water phantom and with expected values in an infinite water medium. A comparison with reported values from proton therapy and intensity-modulated radiation therapy (IMRT) is also provided. Methods: Monte Carlo simulations in Geant4 were performed using a voxelized phantom described in International Commission on Radiological Protection (ICRP) Publication 110, which reproduces masses and shapes from an adult reference man defined in ICRP Publication 89. Point sources of {sup 60}Co or {sup 192}Ir with photon energy spectra corresponding to those exiting their capsules were placed in the center of the prostate, and equivalent doses per clinical absorbed dose in this target organ were obtained in several radiosensitive organs. Values were corrected to account for clinical circumstances with the source located at various positions with differing dwell times throughout the prostate. This was repeated for a homogeneous water phantom. Results: For the nearest organs considered (bladder, rectum, testes, small intestine, and colon), equivalent doses given by {sup 60}Co source were smaller (8%-19%) than from {sup 192}Ir. However, as the distance increases, the more penetrating gamma rays produced by {sup 60}Co deliver higher organ equivalent doses. The overall result is that effective dose per clinical absorbed dose from a {sup 60}Co source (11.1 mSv/Gy) is lower than from a {sup 192}Ir source (13.2 mSv/Gy). On the other hand, equivalent doses were the same in the tissue and the homogeneous water phantom for those soft tissues closer to the prostate than about 30 cm. As the distance increased, the differences of photoelectric effect in water and soft tissue, and appearance of other materials

  5. The effect of patient inhomogeneities in oesophageal 192Ir HDR brachytherapy: a Monte Carlo and analytical dosimetry study

    Science.gov (United States)

    Anagnostopoulos, G.; Baltas, D.; Pantelis, E.; Papagiannis, P.; Sakelliou, L.

    2004-06-01

    The effect of patient inhomogeneities surrounding the oesophagus on the dosimetry planning of an upper thoracic oesophageal 192Ir HDR brachytherapy treatment is studied. The MCNPX Monte Carlo code is used for dosimetry in a patient-equivalent phantom geometry and results are compared in terms of isodose contours as well as dose volume histograms with corresponding calculations by a contemporary treatment planning system software featuring a full TG-43 dose calculation algorithm (PLATO BPS version 14.2.4). It is found that the presence of patient inhomogeneities does not alter the delivery of the planned dose distribution to the planning treatment volume. Regarding the organs at risk, the common practice of current treatment planning systems (TPSs) to consider the patient geometry as a homogeneous water medium leads to a dose overestimation of up to 13% to the spinal cord and an underestimation of up to 15% to the sternum bone. These findings which correspond to the dose region of about 5-10% of the prescribed dose could only be of significance when brachytherapy is used as a boost to external beam therapy. Additionally, an analytical dosimetry model, which is efficient in calculating dose in mathematical phantoms containing inhomogeneity shells of materials of radiobiological interest, is utilized for dosimetry in the patient-equivalent inhomogeneous phantom geometry. Analytical calculations in this work are in good agreement with corresponding Monte Carlo results within the bone inhomogeneities of spinal cord and sternum bone but, like treatment planning system calculations, the model fails to predict the dose distribution in the proximal lung surface as well as within the lungs just as the TPS does, due to its inherent limitation in treating lateral scatter and backscatter radiation.

  6. Implant strategies for endocervical and interstitial ultrasound hyperthermia adjunct to HDR brachytherapy for the treatment of cervical cancer

    Science.gov (United States)

    Wootton, Jeffery H.; Prakash, Punit; Hsu, I.-Chow Joe; Diederich, Chris J.

    2011-07-01

    Catheter-based ultrasound devices provide a method to deliver 3D conformable heating integrated with HDR brachytherapy delivery. Theoretical characterization of heating patterns was performed to identify implant strategies for these devices which can best be used to apply hyperthermia to cervical cancer. A constrained optimization-based hyperthermia treatment planning platform was used for the analysis. The proportion of tissue >=41 °C in a hyperthermia treatment volume was maximized with constraints Tmax 200 cm3) is possible using multiple sectored interstitial and endocervical ultrasound devices. The endocervical device can heat >41 °C to 4.6 cm diameter compared to 3.6 cm for the interstitial. Sectored applicators afford tight control of heating that is robust to perfusion changes in most regularly spaced configurations. T90 in example patient cases was 40.5-42.7 °C (1.9-39.6 EM43 °C) at 1 kg m-3 s-1 with 10/14 patients >=41 °C. Guidelines are presented for positioning of implant catheters during the initial surgery, selection of ultrasound applicator configurations, and tailored power schemes for achieving T90 >= 41 °C in clinically practical implant configurations. Catheter-based ultrasound devices, when adhering to the guidelines, show potential to generate conformal therapeutic heating ranging from a single endocervical device targeting small volumes local to the cervix (directional interstitial applicators in the lateral periphery to target much larger volumes (6 cm radial), while preferentially limiting heating of the bladder and rectum.

  7. SU-F-T-08: Brachytherapy Film Dosimetry in a Water Phantom for a Ring and Tandem HDR Applicator

    Energy Technology Data Exchange (ETDEWEB)

    Lee, B; Grelewicz, Z; Kang, Z; Cutright, D; Gopalakrishnan, M; Sathiaseelan, V; Zhang, H [Northwestern Memorial Hospital, Chicago, IL (United States)

    2016-06-15

    Purpose: The feasibility of dose measurement using new generation EBT3 film was explored in a water phantom for a ring and tandem HDR applicator for measurements tracking mucosal dose during cervical brachytherapy. Methods: An experimental fixture was assembled to position the applicator in a water phantom. Prior to measurement, calibration curves for EBT3 film in water and in solidwater were verified. EBT3 film was placed at different known locations around the applicator in the water tank. A CT scan of the phantom with applicator was performed using clinical protocol. A typical cervical cancer treatment plan was then generated by Oncentra brachytherapy planning system. A dose of 500 cGy was prescribed to point A (2 cm, 2 cm). Locations measured by film included the outer surface of the ring, measurement point A-m (2.2 cm, 2.2 cm), and profiles extending from point A-m parallel to the tandem. Three independent measurements were conducted. The doses recorded by film were carefully analyzed and compared with values calculated by the treatment planning system. Results: Assessment of the EBT3 films indicate that the dose at point A matches the values predicted by the planning system. Dose to the point A-m was 411.5 cGy, and the outer circumferential surface dose of the ring was between 500 and 1150 cGy. It was found that from the point A-m, the dose drops 60% within 4.5 cm on the line parallel to the tandem. The measurement doses agree with the treatment planning system. Conclusion: Use of EBT3 film is feasible for in-water measurements for brachytherapy. A carefully machined apparatus will likely improve measurement accuracy. In a typical plan, our study found that the ring surface dose can be 2.5 times larger than the point A prescription dose. EBT3 film can be used to monitor mucosal dose in brachytherapy treatments.

  8. On the experimental validation of model-based dose calculation algorithms for 192Ir HDR brachytherapy treatment planning

    Science.gov (United States)

    Pappas, Eleftherios P.; Zoros, Emmanouil; Moutsatsos, Argyris; Peppa, Vasiliki; Zourari, Kyveli; Karaiskos, Pantelis; Papagiannis, Panagiotis

    2017-05-01

    There is an acknowledged need for the design and implementation of physical phantoms appropriate for the experimental validation of model-based dose calculation algorithms (MBDCA) introduced recently in 192Ir brachytherapy treatment planning systems (TPS), and this work investigates whether it can be met. A PMMA phantom was prepared to accommodate material inhomogeneities (air and Teflon), four plastic brachytherapy catheters, as well as 84 LiF TLD dosimeters (MTS-100M 1  ×  1  ×  1 mm3 microcubes), two radiochromic films (Gafchromic EBT3) and a plastic 3D dosimeter (PRESAGE). An irradiation plan consisting of 53 source dwell positions was prepared on phantom CT images using a commercially available TPS and taking into account the calibration dose range of each detector. Irradiation was performed using an 192Ir high dose rate (HDR) source. Dose to medium in medium, Dmm , was calculated using the MBDCA option of the same TPS as well as Monte Carlo (MC) simulation with the MCNP code and a benchmarked methodology. Measured and calculated dose distributions were spatially registered and compared. The total standard (k  =  1) spatial uncertainties for TLD, film and PRESAGE were: 0.71, 1.58 and 2.55 mm. Corresponding percentage total dosimetric uncertainties were: 5.4-6.4, 2.5-6.4 and 4.85, owing mainly to the absorbed dose sensitivity correction and the relative energy dependence correction (position dependent) for TLD, the film sensitivity calibration (dose dependent) and the dependencies of PRESAGE sensitivity. Results imply a LiF over-response due to a relative intrinsic energy dependence between 192Ir and megavoltage calibration energies, and a dose rate dependence of PRESAGE sensitivity at low dose rates (required for the full characterization of dosimeter response for 192Ir and the reduction of experimental uncertainties.

  9. Evaluation of linear array MOSFET detectors for in vivo dosimetry to measure rectal dose in HDR brachytherapy.

    Science.gov (United States)

    Haughey, Aisling; Coalter, George; Mugabe, Koki

    2011-09-01

    The study aimed to assess the suitability of linear array metal oxide semiconductor field effect transistor detectors (MOSFETs) as in vivo dosimeters to measure rectal dose in high dose rate brachytherapy treatments. The MOSFET arrays were calibrated with an Ir192 source and phantom measurements were performed to check agreement with the treatment planning system. The angular dependence, linearity and constancy of the detectors were evaluated. For in vivo measurements two sites were investigated, transperineal needle implants for prostate cancer and Fletcher suites for cervical cancer. The MOSFETs were inserted into the patients' rectum in theatre inside a modified flatus tube. The patients were then CT scanned for treatment planning. Measured rectal doses during treatment were compared with point dose measurements predicted by the TPS. The MOSFETs were found to require individual calibration factors. The calibration was found to drift by approximately 1% ±0.8 per 500 mV accumulated and varies with distance from source due to energy dependence. In vivo results for prostate patients found only 33% of measured doses agreed with the TPS within ±10%. For cervix cases 42% of measured doses agreed with the TPS within ±10%, however of those not agreeing variations of up to 70% were observed. One of the most limiting factors in this study was found to be the inability to prevent the MOSFET moving internally between the time of CT and treatment. Due to the many uncertainties associated with MOSFETs including calibration drift, angular dependence and the inability to know their exact position at the time of treatment, we consider them to be unsuitable for in vivo dosimetry in rectum for HDR brachytherapy.

  10. SU-C-BRD-02: A Team Focused Clinical Implementation and Failure Mode and Effects Analysis of HDR Skin Brachytherapy Using Valencia and Leipzig Surface Applicators

    Energy Technology Data Exchange (ETDEWEB)

    Sayler, E; Harrison, A; Eldredge-Hindy, H; Dinome, J; Munro, S; Anne, R; Comber, E; Lockamy, V [Bodine Center for Cancer Treatment, Thomas Jefferson University, Philadelphia, PA (United States)

    2014-06-15

    Purpose: and Leipzig applicators (VLAs) are single-channel brachytherapy surface applicators used to treat skin lesions up to 2cm diameter. Source dwell times can be calculated and entered manually after clinical set-up or ultrasound. This procedure differs dramatically from CT-based planning; the novelty and unfamiliarity could lead to severe errors. To build layers of safety and ensure quality, a multidisciplinary team created a protocol and applied Failure Modes and Effects Analysis (FMEA) to the clinical procedure for HDR VLA skin treatments. Methods: team including physicists, physicians, nurses, therapists, residents, and administration developed a clinical procedure for VLA treatment. The procedure was evaluated using FMEA. Failure modes were identified and scored by severity, occurrence, and detection. The clinical procedure was revised to address high-scoring process nodes. Results: Several key components were added to the clinical procedure to minimize risk probability numbers (RPN): -Treatments are reviewed at weekly QA rounds, where physicians discuss diagnosis, prescription, applicator selection, and set-up. Peer review reduces the likelihood of an inappropriate treatment regime. -A template for HDR skin treatments was established in the clinical EMR system to standardize treatment instructions. This reduces the chances of miscommunication between the physician and planning physicist, and increases the detectability of an error during the physics second check. -A screen check was implemented during the second check to increase detectability of an error. -To reduce error probability, the treatment plan worksheet was designed to display plan parameters in a format visually similar to the treatment console display. This facilitates data entry and verification. -VLAs are color-coded and labeled to match the EMR prescriptions, which simplifies in-room selection and verification. Conclusion: Multidisciplinary planning and FMEA increased delectability and

  11. An absorbed dose to water standard for HDR 192Ir brachytherapy sources based on water calorimetry: numerical and experimental proof-of-principle.

    Science.gov (United States)

    Sarfehnia, Arman; Stewart, Kristin; Seuntjens, Jan

    2007-12-01

    Water calorimetry is an established technique for absorbed dose to water measurements in external beams. In this paper, the feasibility of direct absorbed dose measurements for high dose rate (HDR) iridium-192 (192Ir) sources using water calorimetry is established. Feasibility is determined primarily by a balance between the need to obtain sufficient signal to perform a reproducible measurement, the effect of heat loss on the measured signal, and the positioning uncertainty affecting the source-detector distance. The heat conduction pattern generated in water by the Nucletron microSelectron-HDR 192Ir brachytherapy source was simulated using COMSOL MULTIPHYSICS software. Source heating due to radiation self-absorption was calculated using EGSnrcMP. A heat-loss correction k(c) was calculated as the ratio of the temperature rise under ideal conditions to temperature rise under realistic conditions. The calorimeter setup used a parallel-plate calorimeter vessel of 79 mm diameter and 1.12 mm thick front and rear glass windows located 24 mm apart. Absorbed dose was measured with two sources with nominal air kerma strengths of 38 000 and 21 000 U, at source-detector separations ranging from 24.7 to 27.6 mm and irradiation times of 36.0 to 80.0 s. The preliminary measured dose rate per unit air kerma strength of (0.502 +/- 0.007) microGy/(s U) compares well with the TG-43 derived 0.505 microGy/(s U). This work shows that combined dose uncertainties of significantly less than 5% can be achieved with only modest modifications of current water calorimetry techniques and instruments. This work forms the basis of a potential future absolute dose to water standard for HDR 192Ir brachytherapy.

  12. Implants quality in HDR prostate brachytherapy related to the number of needles used;Qualidade de implantes de prostata com BATD em funcao do numero de agulhas usadas

    Energy Technology Data Exchange (ETDEWEB)

    Moura, Dayanne E.E.S; Martins, Homero L. [Hospital A.C. Camargo, Sao Paulo, SP (Brazil). Servico de Fisica Medica

    2009-07-01

    This paper aims to relate the quality of prostate implants (HDR) with the amount of needles used. 51 needle insertions performed in the institution were analyzed. The maximum diameter, the maximum height and target volume delineated by radiation oncologist were measured and this compared with the prostate volume obtained by the radiologist. It was concluded that the prostate volume measured by the radiologist is not a reliable indication to determine how the implant will be done and that the increase in the number of needles implanted did not necessarily ensure a better dose distribution. (author)

  13. Temporo-spatial cell-cycle kinetics in HeLa cells irradiated by Ir-192 high dose-rate remote afterloading system (HDR-RALS).

    Science.gov (United States)

    Asahina, Taito; Kaida, Atsushi; Goto, Tatsuaki; Yoshimura, Ryo-Ichi; Sasai, Keisuke; Miura, Masahiko

    2016-07-29

    Intracavitary irradiation plays a pivotal role in definitive radiotherapy for cervical cancer, and the Ir-192 high dose-rate remote afterloading system (HDR-RALS) is often used for this purpose. Under this condition, tumor tissues receive remarkably different absorption doses, with a steep gradient, depending on distance from the radiation source. To obtain temporo-spatial information regarding cell-cycle kinetics in cervical cancer following irradiation by Ir-192 HDR-RALS, we examined HeLa cells expressing the fluorescence ubiquitination-based cell cycle indicator (Fucci), which allowed us to visualize cell-cycle progression. HeLa-Fucci cells, which emit red and green fluorescence in G1 and S/G2/M phases, respectively, were grown on 35-mm dishes and irradiated by Ir-192 HDR-RALS under normoxic and hypoxic conditions. A 6 French (Fr) catheter was used as an applicator. A radiation dose of 6 Gy was prescribed at hypothetical treatment point A, located 20 mm from the radiation source. Changes in Fucci fluorescence after irradiation were visualized for cells from 5 to 20 mm from the Ir-192 source. Several indices, including first green phase duration after irradiation (FGPD), were measured by analysis of time-lapse images. Cells located 5 to 20 mm from the Ir-192 source became green, reflecting arrest in G2, in a similar manner up to 12 h after irradiation; at more distant positions, however, cells were gradually released from the G2 arrest and became red. This could be explained by the observation that the FGPD was longer for cells closer to the radiation source. Detailed observation revealed that FGPD was significantly longer in cells irradiated in the green phase than in the red phase at positions closer to the Ir-192 source. Unexpectedly, the FGPD was significantly longer after irradiation under hypoxia than normoxia, due in large part to the elongation of FGPD in cells irradiated in the red phase. Using HeLa-Fucci cells, we obtained the first temporo

  14. SU-F-T-37: Dosimetric Evaluation of Planned Versus Decay Corrected Treatment Plans for the Treatment of Tandem-Based Cervical HDR Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Goyal, M [Texas Oncology, PA, Fort Worth, TX (United States); Shobhit University, Meerut, Uttar Pradesh (India); Manjhi, J; Rai, D [Shobhit University, Meerut, Uttar Pradesh (India); Kehwar, T [Pinnacle Health Cancer Center, Mechanicsburg, PA (United States); Barker, J; Heintz, B; Shide, K [Texas Oncology, PA, Fort Worth, TX (United States)

    2016-06-15

    Purpose: This study evaluated dosimetric parameters for actual treatment plans versus decay corrected treatment plans for cervical HDR brachytherapy. Methods: 125 plans of 25 patients, who received 5 fractions of HDR brachytherapy, were evaluated in this study. Dose was prescribed to point A (ICRU-38) and High risk clinical tumor volume (HR-CTV) and organs at risk (OAR) were, retrospectively, delineated on original CT images by treating physician. First HDR plan was considered as reference plan and decay correction was applied to calculate treatment time for subsequent fractions, and was applied, retrospectively, to determine point A, HR-CTV D90, and rectum and bladder doses. Results: The differences between mean point A reference doses and the point A doses of the plans computed using decay times were found to be 1.05%±0.74% (−2.26% to 3.26%) for second fraction; −0.25%±0.84% (−3.03% to 3.29%) for third fraction; 0.04%±0.70% (−2.68% to 2.56%) for fourth fraction and 0.30%±0.81% (−3.93% to 2.67%) for fifth fraction. Overall mean point A dose difference, for all fractions, was 0.29%±0.38% (within ± 5%). Mean rectum and bladder dose differences were calculated to be −3.46%±0.12% and −2.47%±0.09%, for points, respectively, and −1.72%±0.09% and −0.96%±0.06%, for D2cc, respectively. HR-CTV D90 mean dose difference was found to be −1.67% ± 0.11%. There was no statistically significant difference between the reference planned point A doses and that calculated using decay time to the subsequent fractions (p<0.05). Conclusion: This study reveals that a decay corrected treatment will provide comparable dosimetric results and can be utilized for subsequent fractions of cervical HDR brachytherapy instead of actual treatment planning. This approach will increase efficiency, decrease workload, reduce patient observation time between applicator insertion and treatment delivery. This would be particularly useful for institutions with limited

  15. SU-F-T-31: Shape and Isodose Distributions in Co60 HDR Brachytherapy for Different Utero-Vaginal Time Ratios

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Sprinberg, G [Faculty of Sciences, Montevideo, Montevideo (Venezuela, Bolivarian Republic of); Piriz, G [Hospital Pereyra Rossell, Montevideo, Montevideo (Venezuela, Bolivarian Republic of)

    2016-06-15

    Purpose: To optimize the dose in bladder and rectum and show the different shapes of the isodose volumes in Co60-HDR brachytherapy, considering different utero and vaginal sources dwell ratio times (TU:TV). Methods: Besides Ir192-HDR, new Co60-HDR sources are being incorporated. We considered different TU:TV times and computed the dosis in bladder, rectum and at the reference points of the Manchester system. Also, we calculated the isodose volume and shape in each case. We used a EZAG-BEBIG Co0.A86 model with TPS HDRplus3.0.4. and LCT42-7, LCT42-2(R,L) applicators. A reference dose RA= 1.00 Gy was given to the A-right point. We considered the TU:TV dwell time ratios 1:0.25, 1:0.33, 1:0.5, 1:1, 1:2, 1:3, and 1:4. Given TU:TV, the stop time at each dwell position is fixed for each applicator. Results: Increasing TU:TV systematically results in a decreasing of the dose in bladder and rectum, e.g. 9% and 27% reduction were found in 1:0.25 with respect to 1:1, while 12% and 34% increase were found in 1:4 with respect to 1:1. Also, the isodose volume parameters height (h), width (w), thickness (t) and volume (hwt) increased from the 1:0.25 case to the 1:4 value: hwt is 25% lower and 31% higher than the 1:1 reference volume in these cases. Also w decreased for higher TU:TV and may compromise the tumoral volume coverage, decreasing 17% in the 1:0.25 case compared to the 1:1 case. The shape of the isodose volume was obtained for the different TU:TV considered. Conclusion: We obtained the shape of isodose volumes for different TU:TV values in gynecological Co60-HDR. We studied the dose reduction in bladder and rectum for different TU:TV ratios. The volume parameters and hwt are strongly dependent on this ratio. This information is useful for a quantitative check of the TPS and as a starting point towards optimization.

  16. Medically inoperable endometrial cancer in patients with a high body mass index (BMI): Patterns of failure after 3-D image-based high dose rate (HDR) brachytherapy.

    Science.gov (United States)

    Acharya, Sahaja; Esthappan, Jacqueline; Badiyan, Shahed; DeWees, Todd A; Tanderup, Kari; Schwarz, Julie K; Grigsby, Perry W

    2016-01-01

    High BMI is a reason for medical inoperability in patients with endometrial cancer in the United States. Definitive radiation is an alternative therapy for these patients; however, data on patterns of failure after definitive radiotherapy are lacking. We describe the patterns of failure after definitive treatment with 3-D image-based high dose rate (HDR) brachytherapy for medically inoperable endometrial cancer. Forty-three consecutive patients with endometrial cancer FIGO stages I-III were treated definitively with HDR brachytherapy with or without external beam radiation therapy. Cumulative incidence of failures was estimated and prognostic variables were identified Mean follow up was 29.7 months. Median BMI was 50.2 kg/m(2) (range: 25.1-104 kg/m(2)). The two-year overall survival was 65.2%. The two-year cumulative incidence of pelvic and distant failures was 8.3% and 13.5%, respectively. Grade 3 disease was associated with a higher risk of all-failures (Hazard Ratio [HR]: 4.67, 95% CI: 1.04-20.9, p=0.044). The incidence of acute Grade 3 GI/GU toxicities was 4.6%. Pelvic failure at two years was less than 10%. Patients with grade 3 disease were more likely to experience disease failure and may warrant closer follow up. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  17. Exploration of joint systems and major horizontal stress direction in HDR drillholes of the Soultz site (Alsace, France)

    Energy Technology Data Exchange (ETDEWEB)

    Genter, A. [BRGM/GIG, Orleans (France); Tenzer, H. [Stadtwerke Bad Urach (Germany)

    1997-12-01

    Borehole imaging logs enable continuous recording of natural and artificial planar discontinuities on the drillhole wall and data of the drillhole geometry to be made. Efforts were made to resolve the orientation and characterization of the natural joint system, the active fault pattern, the alteration zones, the orientation of microcracks and the direction of maximum horizontal stress. Intense logging operations and measurements were carried out in the HDR drillholes GPK1 and EPS1 between 1000 and 3600 m depth in the Muschelkalk, Bunter and Granite at Soultz sous Forets. With the help of investigations on subvertical fractures the orientation of the maximum horizontal stress direction was determined as N175 E{+-}17 . These results are consistent with previous investigations performed in the horeholes GPK-1 and EPS-1. (orig./AKF) [Deutsch] Bohrlochmessungen mit dem akustschen Borehole Televiewer und elektrischen Formation MicroScanner (Imager) sowie dem Azimuthal Resistivity Imager und verschiedenen Sonic-Sonden ermoeglichen eine kontinuierliche Aufnahme sowohl von natuerlichen und kuenstlich erzeugten planaren Diskontinuitaeten an der Bohrlochwand als auch der Bohrlochgeometrie. Es wurden die Orientierung und Charakterisierung des natuerlichen Kluftsystems, das aktive Stoerungsmuster, die Alterationszonen, die Orientierung von Mikrorissen und die Orientierung der maximalen horizontalen Hauptspannungsrichtung ermittelt. Die Verfuegbarkeit von Strukturdaten aus Bohrloechern durch Bohrlochmessungen und hydraulischen Testen ermoeglicht die Bestimmung von hydraulisch aktiven Klueften und deren Beziehung zum regionalen Spannungsfeld. Mit Hilfe spezieller Bohrloch-Logs wurden die Orientierung und Haeufigkeit planarer Diskontinuitaeten und ihre scheinbare Oeffnungsweite sowie die Vorzugsrichtung der verschiedenen scheinbaren Weiten bestimmt. Innerhalb des gemeinsamen europaeischen Hot-Dry-Rock-Geothermal-Forschungsprogramms wurden vielfaeltige Bohrlochmessungen in den

  18. Proposal of a high dose rate brachytherapy model for radiobiology studies in vitro; Proposta de um modelo de braquiterapia de alta taxa de dose para estudos de radiobiologia in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Geraldo, Jony M.; Andrade, Lidia M., E-mail: jony.marques@mariopenna.org.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte (Brazil). Departamento de Fisica; Trindade, Cassia [Hospital Luxemburgo, Belo Horizonte, MG (Brazil); Nogueira, Luciana B. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte (Brazil). Faculdade de Medicina; Furtado, Clascidia A.; Ladeira, Luiz Orlando [Centro de Desenvolvimento da Tecnologia Nuclear (CTDN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2016-07-01

    The aim of this research was to develop an easy and reproducible approach for experimental HDR brachytherapy allowing in vitro irradiation studies based on clinical parameters. An acrylic platform was designed to attach T25 tissue culture flasks and multi-well tissue culture plates as well as kept the catheters in a fixed position during irradiation. CT images were taken and the irradiation was planned for 550cGy dose applied on adherent tumor cells. Dosimetric measurements were done and all relevant uncertainties were taken into account in order to figure out the correct dose range received by the cells. Tumor cells were irradiated two times over an interval of 24h between irradiations. Proof of concepts of this approach was carried out by biological effects analysis using a radioresistant human epidermoid carcinoma A431 cell line. Cellular proliferation and cell cycle phase were assessed by Trypan blue exclusion assay and DNA content analysis by flow cytometry, respectively. This approach allowed uniform dose distribution around the arrangement in all types of tissue culture plastics evaluated. Corrections due to uncertainties were managed. Regarding in vitro assays there was a significant (p<0.05) decreasing of cellular proliferation rate in irradiated cells. Moreover, increased percentage of cells arrested in G2/M phase (32.3 ± 1.5%) were observed for treated group compared with untreated cells. (author)

  19. Proposal of a high dose rate brachytherapy model for in vitro radiobiology studies; Proposta de um modelo de braquiterapia de alta taxa de dose para estudos de radiobiologia in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Geraldo, Jony M.; Nogueira, Luciana B.; Andrade, Lidia M. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil); Trindade, Cassia [Hospital Luxemburgo, Belo Horizonte, MG (Brazil); Furtado, Clascidia A.; Ladeira, Luiz Orlando, E-mail: jony.marques@mariopenna.org.br [Centro de Desenvolvimento da Tecnologia Nuclear (CTDN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2016-07-01

    The aim of this research was to develop an easy and reproducible approach for experimental HDR brachytherapy allowing in vitro irradiation studies based on clinical parameters. An acrylic platform was designed to attach T25 tissue culture flasks and multi-well tissue culture plates as well as kept the catheters in a fixed position during irradiation. CT images were taken and the irradiation was planned for 550cGy dose applied on adherent tumor cells. Dosimetric measurements were done and all relevant uncertainties were taken into account in order to figure out the correct dose range received by the cells. Tumor cells were irradiated two times over an interval of 24h between irradiations. Proof of concepts of this approach was carried out by biological effects analysis using a radioresistant human epidermoid carcinoma A431 cell line. Cellular proliferation and cell cycle phase were assessed by Trypan blue exclusion assay and DNA content analysis by flow cytometry, respectively. This approach allowed uniform dose distribution around the arrangement in all types of tissue culture plastics evaluated. Corrections due to uncertainties were managed. Regarding in vitro assays there was a significant (p<0.05) decreasing of cellular proliferation rate in irradiated cells. Moreover, increased percentage of cells arrested in G2/M phase (32.3 ± 1.5%) were observed for treated group compared with untreated cells. (author)

  20. SU-F-T-14: Dosimetric Impacts of Various Uncertainties in Cervical Cancer HDR Brachytherapy: Are Conventional Point Doses Good Surrogates for 3D Dosimetry?

    Energy Technology Data Exchange (ETDEWEB)

    Liang, X; Li, Z [University of Florida Health Proton Therapy Institute, Jacksonville, FL (United States); Zheng, D [University of Nebraska Medical Center, Omaha, NE (United States); Zhang, X; Narayanasamy, G; Morrill, S; Penagaricano, J; Paudel, N [University of Arkansas for Medical Sciences, Little Rock, AR (United States)

    2016-06-15

    Purpose: In the context of evaluating dosimetric impacts of a variety of uncertainties involved in HDR Tandem-and-Ovoid treatment, to study the correlations between conventional point doses and 3D volumetric doses. Methods: For 5 cervical cancer patients treated with HDR T&O, 150 plans were retrospectively created to study dosimetric impacts of the following uncertainties: (1) inter-fractional applicator displacement between two treatment fractions within a single insertion by applying Fraction#1 plan to Fraction#2 CT; (2) positional dwell error simulated from −5mm to 5mm in 1mm steps; (3) simulated temporal dwell error of 0.05s, 0.1s, 0.5s, and 1s. The original plans were based on point dose prescription, from which the volume covered by the prescription dose was generated as the pseudo target volume to study the 3D target dose effect. OARs were contoured. The point and volumetric dose errors were calculated by taking the differences between original and simulated plans. The correlations between the point and volumetric dose errors were analyzed. Results: For the most clinically relevant positional dwell uncertainty of 1mm, temporal uncertainty of 0.05s, and inter-fractional applicator displacement within the same insertion, the mean target D90 and V100 deviation were within 1%. Among these uncertainties, the applicator displacement showed the largest potential target coverage impact (2.6% on D90) as well as the OAR dose impact (2.5% and 3.4% on bladder D2cc and rectum D2cc). The Spearman correlation analysis shows a correlation coefficient of 0.43 with a p-value of 0.11 between target D90 coverage and H point dose. Conclusion: With the most clinically relevant positional and temporal dwell uncertainties and patient interfractional applicator displacement within the same insertion, the dose error is within clinical acceptable range. The lack of correlation between H point and 3D volumetric dose errors is a motivator for the use of 3D treatment planning in

  1. SU-C-16A-01: In Vivo Source Position Verification in High Dose Rate (HDR) Prostate Brachytherapy Using a Flat Panel Imager: Initial Clinical Experience

    Energy Technology Data Exchange (ETDEWEB)

    Franich, R; Smith, R; Millar, J [RMIT University, Melbourne, Victoria (Australia); The Alfred Hospital, Melbourne, Victoria (Australia); Haworth, A [RMIT University, Melbourne, Victoria (Australia); Peter MacCallum Cancer Centre, Melbourne, Victoria (Australia); Taylor, M [RMIT University, Melbourne, Victoria (Australia); Australian Federal Police, Canberra, ACT (Australia); McDermott, L [RMIT University, Melbourne, Victoria (Australia)

    2014-06-15

    Purpose: We report our initial clinical experience with a novel position-sensitive source-tracking system based on a flat panel imager. The system has been trialled with 4 prostate HDR brachytherapy patients (8 treatment fractions) in this initial study. Methods: The flat panel imaging system was mounted under a customised carbon fibre couch top assembly (Figure 1). Three gold fiducial markers were implanted into the prostate of each patient at the time of catheter placement. X-ray dwell position markers were inserted into three catheters and a radiograph acquired to locate the implant relative to the imaging device. During treatment, as the HDR source dwells were delivered, images were acquired and processed to determine the position of the source in the patient. Source positions measured by the imaging device were compared to the treatment plan for verification of treatment delivery. Results: Measured dwell positions provided verification of relative dwell spacing within and between catheters, in the coronal plane. Measurements were typically within 2.0mm (0.2mm – 3.3mm, s.d. 0.8mm) of the planned positions over 60 dwells (Figure 2). Discrimination between larger dwell intervals and catheter differentiation were clear. This confirms important delivery attributes such as correct transfer tube connection, source step size, relative catheter positions and therefore overall correct plan selection and delivery. The fiducial markers, visible on the radiograph, provided verification of treatment delivery to the correct anatomical location. The absolute position of the dwells was determined by comparing the measured dwell positions with the x-ray markers from the radiograph, validating the programmed treatment indexer length. The total impact on procedure time was less than 5 minutes. Conclusion: The novel, noninvasive HDR brachytherapy treatment verification system was used clinically with minor impact on workflow. The system allows verification of correct treatment

  2. Objective method to report planner-independent skin/rib maximal dose in balloon-based high dose rate (HDR) brachytherapy for breast cancer.

    Science.gov (United States)

    Kim, Yongbok; Trombetta, Mark G

    2011-04-01

    An objective method was proposed and compared with a manual selection method to determine planner-independent skin and rib maximal dose in balloon-based high dose rate (HDR) brachytherapy planning. The maximal dose to skin and rib was objectively extracted from a dose volume histogram (DVH) of skin and rib volumes. A virtual skin volume was produced by expanding the skin surface in three dimensions (3D) external to the breast with a certain thickness in the planning computed tomography (CT) images. Therefore, the maximal dose to this volume occurs on the skin surface the same with a conventional manual selection method. The rib was also delineated in the planning CT images and its maximal dose was extracted from its DVH. The absolute (Abdiff = [D(max) Man - D (max)DVH]) and relative (Rediff[%] = 100 x ([D(max)Man-D(max)DVH])/D(max)DVH) maximal skin and rib dose differences between the manual selection method (D(max)Man) and the objective method (D(max)DVH) were measured for 50 balloon-based HDR (25 MammoSite and 25 Contura) patients. The average +/- standard deviation of maximal dose difference was 1.67% +/- 1.69% of the prescribed dose (PD). No statistical difference was observed between MammoSite and Contura patients for both Abdiff and Rediff[%] values. However, a statistically significant difference (p value skin dose difference for both Abdiff (2.30% +/- 1.71% vs 1.05% +/- 1.43%) and Rediff[%] (2.32% +/- 1.79% vs 1.21% +/- 1.41%). In general, rib has a more irregular contour and it is more proximally located to the balloon for 50 HDR patients. Due to the inverse square law factor, more dose difference was observed in higher dose range (D(max) > 90%) compared with lower dose range (D(max) skin and rib can determine the planner-independent maximal dose compared with the manual selection method. However, the difference was < 2% of PD, on average, if appropriate attention is paid to selecting a manual dose point in 3D planning CT images.

  3. Objective method to report planner-independent skin/rib maximal dose in balloon-based high dose rate (HDR) brachytherapy for breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yongbok; Trombetta, Mark G. [Department of Radiation Oncology, Allegheny General Hospital, Pittsburgh, Pennsylvania 15212 (United States) and Drexel University College of Medicine, Allegheny Campus, Pittsburgh, Pennsylvania 15212 (United States)

    2011-04-15

    Purpose: An objective method was proposed and compared with a manual selection method to determine planner-independent skin and rib maximal dose in balloon-based high dose rate (HDR) brachytherapy planning. Methods: The maximal dose to skin and rib was objectively extracted from a dose volume histogram (DVH) of skin and rib volumes. A virtual skin volume was produced by expanding the skin surface in three dimensions (3D) external to the breast with a certain thickness in the planning computed tomography (CT) images. Therefore, the maximal dose to this volume occurs on the skin surface the same with a conventional manual selection method. The rib was also delineated in the planning CT images and its maximal dose was extracted from its DVH. The absolute (Abdiff=|D{sub max}{sup Man}-D{sub max}{sup DVH}|) and relative (Rediff[%]=100x(|D{sub max}{sup Man}-D{sub max}{sup DVH}|)/D{sub max}{sup DVH}) maximal skin and rib dose differences between the manual selection method (D{sub max}{sup Man}) and the objective method (D{sub max}{sup DVH}) were measured for 50 balloon-based HDR (25 MammoSite and 25 Contura) patients. Results: The average{+-}standard deviation of maximal dose difference was 1.67%{+-}1.69% of the prescribed dose (PD). No statistical difference was observed between MammoSite and Contura patients for both Abdiff and Rediff[%] values. However, a statistically significant difference (p value <0.0001) was observed in maximal rib dose difference compared with maximal skin dose difference for both Abdiff (2.30%{+-}1.71% vs 1.05%{+-}1.43%) and Rediff[%] (2.32%{+-}1.79% vs 1.21%{+-}1.41%). In general, rib has a more irregular contour and it is more proximally located to the balloon for 50 HDR patients. Due to the inverse square law factor, more dose difference was observed in higher dose range (D{sub max}>90%) compared with lower dose range (D{sub max}<90%): 2.16%{+-}1.93% vs 1.19%{+-}1.25% with p value of 0.0049. However, the Rediff[%] analysis eliminated the

  4. Avaliação dosimétrica de uma combinação de aplicadores para braquiterapia de tumores do colo uterino com acometimento da porção distal da vagina Dosimetric evaluation of a combination of brachytherapy applicators for uterine cervix cancer with involvement of the distal vagina

    Directory of Open Access Journals (Sweden)

    Roger Guilherme Rodrigues Guimarães

    2009-08-01

    Full Text Available OBJETIVO: Avaliar uma alternativa de braquiterapia para tumores do colo uterino acometendo a porção distal da vagina, sem aumentar os riscos de toxicidade. MATERIAIS E MÉTODOS: Estudo teórico comparando três diferentes aplicadores de braquiterapia intracavitária de alta taxa de dose: sonda intrauterina e cilindro vaginal (SC; sonda e anel associado ao cilindro vaginal (SA+C e um aplicador virtual com sonda, anel e cilindro vaginal em um único conjunto (SAC. Foram prescritas doses de 7 Gy no ponto A e 5 Gy na superfície ou a 5 mm de profundidade na mucosa vaginal, mantendo as doses nos pontos de reto, bexiga e sigmoide abaixo dos limites de tolerância. Foram comparados os volumes englobados pelas isodoses de 50% (V50, 100% (V100, 150% (V150 e 200% (V200, respectivamente. RESULTADOS: Tanto SA+C quanto SAC apresentaram melhor distribuição de dose quando comparados ao aplicador SC. A distribuição de dose obtida com SA+C foi semelhante à do aplicador SAC, sendo V150 e V200 cerca de 50% maiores para SA+C, todavia, dentro do cilindro. CONCLUSÃO: A utilização de SA+C em uma única aplicação em dois tempos pode ser uma alternativa de tratamento para pacientes que apresentam tumores de colo uterino com acometimento distal da vagina.OBJECTIVE: To evaluate an alternative brachytherapy technique for uterine cervix cancer involving the distal vagina, without increasing the risk of toxicity. MATERIALS AND METHODS: Theoretical study comparing three different high-dose rate intracavitary brachytherapy applicators: intrauterine tandem and vaginal cylinder (TC; tandem/ring applicator combined with vaginal cylinder (TR+C; and a virtual applicator combining both the tandem/ring and vaginal cylinder in a single device (TRC. Prescribed doses were 7 Gy at point A, and 5 Gy on the surface or at a 5 mm depth of the vaginal mucosa. Doses delivered to the rectum, bladder and sigmoid colon were kept below the tolerance limits. Volumes covered by the

  5. Cirurgia conservadora, radioterapia externa e reforço de dose com braquiterapia de alta taxa de dose: uma nova perspectiva no tratamento de sarcomas de partes moles do adulto Limb-sparing surgery, external beam radiotherapy and boost with high-dose rate brachytherapy: a new perspective for the treatment of soft tissue sarcomas in adults

    Directory of Open Access Journals (Sweden)

    Antonio Cássio Assis Pellizzon

    2002-03-01

    Full Text Available OBJETIVO: Avaliar a influência no controle local de pacientes adultos e portadores de sarcoma de partes moles em extremidades e submetidos a cirurgia conservadora do membro, com braquiterapia de alta taxa de dose (BATD como reforço para a radioterapia externa (RT. MATERIAL E MÉTODOS: Foram avaliados 16 pacientes tratados, de 1993 até 1999. A RT foi utilizada com finalidade pré ou pós-operatória (30--55 Gy e BATD com dose de 18--36 Gy (fx 3--6 Gy BID. Com base no modelo linear quadrático calculou-se a dose efetiva biológica ("biological effective dose" - BED para o tumor e comparou-se seu valor a dados da literatura internacional, que utiliza tratamentos com RT e braquiterapia de baixa taxa de dose (BBTD. RESULTADOS: Os valores médios e medianos da BED para os sarcomas de partes moles foram de 78,5 Gy7 e 80 Gy7. A análise univariada mostrou que a BED para o tumor, quando utilizada BATD, era semelhante ao valor de 83 Gy7 quando utilizada BBTD (p = 0,008. As taxas de controle local, sobrevida livre de doença e sobrevida global atuarial em cinco anos foram de 83,2%, 75% e 93,7%, respectivamente. CONCLUSÕES: A BATD, quando utilizada como método complementar no reforço de dose da RT no tratamento conservador dos sarcomas de partes moles, apresenta taxas de controle local equiparáveis às da literatura internacional; no entanto, estudos com número maior de pacientes e período maior de seguimento são ainda necessários para determinar o verdadeiro potencial da BATD em substituir a BBTD.PURPOSE: To evaluate the influence on local control in adult patients with soft tissue sarcomas of the limbs that underwent limb-sparing surgery and high-dose rate brachytherapy (HDRB in association with teletherapy. MATERIAL AND METHODS: Sixteen patients treated from 1993 to 1999 were reviewed. Teletherapy was used pre- or postoperatively (30--55 Gy in association with HDRB in a dose range of 18--36 Gy (fx 3--6 Gy BID. The linear quadratic model was

  6. Image-Guided High-Dose-Rate (HDR) Boost Localization Using MRI/MR Spectroscopy: A Correlation Study with Biopsy.

    Science.gov (United States)

    Vigneault, Eric; Mbodji, Khaly; Racine, Louis G; Chevrette, Eric; Lavallee, Marie C; Martin, André-Guy; Despres, Philippe; Beaulieu, Luc

    2016-09-21

    .1% (66.5% - 92.5%), respectively, and a PPV and NPV of 89.4% (79.4% - 95.6%) and 88.9% (73.9% - 96.9%), respectively. Finally, after combining MRI, MRS, and DWI-ADC mapping, compared with biopsy, we obtained a Sn, Sp, PPV, and NPV of 100% (94.8% - 100%), 49% (34.8% - 63.4%), 72.6% (62.5% - 81.3%), and 100% (86.3% - 100%), respectively. The combination of MRI/MRS is a sensitive tool for both the structural and metabolic evaluation of prostate cancer location. MRI/MRS exams are useful to delineate a DIL for high-dose-rate (HDR) intraprostatic boost.

  7. Surface dose characterisation of the Varian Ir-192 HDR conical surface applicator set with a vertically orientated source

    Energy Technology Data Exchange (ETDEWEB)

    Buchauer, Konrad; Henke, Guido; Schiefer, Hans; Plasswilm, Ludwig [Kantonsspital St. Gallen, Department of Radiation Oncology, St. Gallen (Switzerland)

    2014-12-15

    etabliertes Mittel um mit Ir-192 HDR-Brachytherapie nichtmelanomatoese Hautkrebserkrankungen mit hohen Tumorkontrollraten zu behandeln. In dieser Arbeit wird eine hochaufloesende Analyse der Oberflaechendosis eines Varian-Varisource-GammaMed+ IX-Afterloader-Konus-Applikatorsatzes des vertikalen Typs dargestellt. Analyse der Oberflaechendosisverteilung des Applikatorsatzes im Hinblick auf Unregelmaessigkeiten, die fuer aehnliche Applikatoren bereits berichtet wurden. Weiterhin wird untersucht, ob Applikatoren des vertikalen Typs zusaetzliche Verfahren als Ergaenzung der aktuell vorgeschlagenen Methoden zur Verifikation des Dosisoutputs von konischen Oberflaechenapplikatoren benoetigen. Die Verifikation der absoluten Dosis wird nach Herstellerangaben durchgefuehrt. Die Dosisverteilung an der Oberflaeche wird zusaetzlich mit Gafchromic-EBT3-Filmdosimetrie bestimmt. Der Begriff ''therapeutische Dosis'' ist in dieser Arbeit mit 85 % der verschriebenen Dosis definiert. Zehn ausgewertete Applikatoren zeigen Unterdosierungen in der Applikatormitte, mit einer mittlere Groesse von 2,0 mm x 3,6 mm (± 0,6 mm), dosimetrisch deutlich unter 85 % der verschriebenen Dosis. Die Unterdosierung liegt 2,2 mm (1,4-2,7 mm) seitlich der Zentralachse und verursacht eine generelle Asymmetrie in der Dosisverteilung. Ein Schiefstand von 8 (± 1 ) wurde fuer die verwendete Quelle bestimmt. Eine um mehr als 15 % reduzierte Dosis in der Applikatormitte wurde bei Oberflaechenapplikatoren bislang nicht berichtet. Quellenschiefstand wurde als Parameter identifiziert, der die Handhabung dieser Oberflaechenapplikatoren und moeglicherweise den Therapieerfolg beeinflussen kann. Das beschriebene kleinraeumige Dosisartefakt kann systematischen Einfluss auf kammerbasierte Dosisverifikationsverfahren haben. Wir empfehlen daher bei der Applikatorkommissionierung eine zusaetzliche Absicherung mit Filmdosimetrie. (orig.)

  8. Adjuvant radiation therapy for the treatment of endometrial cancer: experience with combination of external radiation therapy and high-dose rate brachytherapy; Radioterapia adjuvante no tratamento do cancer de endometrio: experiencia com a associacao de radioterapia externa e braquiterapia de alta taxa de dose

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Michael Jenwei; Novaes, Paulo Eduardo Ribeiro Soares; Pellizzon, Antonio Cassio de Assis; Ferrigno, Robson; Fogaroli, Ricardo Cesar; Maia, Maria Aparecida Conte; Salvajoli, Joao Victor [Hospital do Cancer A.C. Camargo, Sao Paulo, SP (Brazil). Dept. de Radioterapia]. E-mail: michael.chen@ig.com.br; Nishimoto, Ines Nobuko [Hospital do Cancer A.C. Camargo, Sao Paulo, SP (Brazil). Centro de Estudos

    2005-12-01

    Objective: To review the results of adjuvant external beam radiation therapy (EBRT) combined with high-dose rate brachytherapy (HDR-BT) for the treatment of endometrial carcinoma. Materials and methods: We retrospectively evaluated 141 patients treated with EBRT and HDR-BT after surgery between January 1993 and January 2001. EBRT was performed with a median dose of 45 Gy, and HDR-BT was performed with a median dose of 24 Gy, with four weekly insertions of 6 Gy. The median age of the patients was 63 years and the disease stage distribution was: CS I (FIGO), 52.4%; CS II, 13.5%; CS III, 29.8%; CS IV, 4.3%. Results: With a median follow-up of 53.7 months, the disease free survival (DFS) at five years was: CS I, 88.0%; CS II, 70.8%; CS III, 55.1%; CS IV, 50.0% (p = 0.0003). Global survival after five years was: CS I, 79.6%; CS II, 74.0%; CS III, 53.6%; CS IV, 100.0% (p = 0.0062). Factors affecting the DFS were histological grade and serous-papillary histology. Recurrence of the disease was observed in 33 cases, 13 (9.2%) of these occurred in the pelvis, vagina or vaginal vault. EBRT + HDR-BT of the vaginal vault allowed disease control in 90.8% of the cases. Conclusion: Radiation therapy is essential for loco-regional control of endometrial cancer and can achieve excellent cure rates in the initial stages. In more advanced stages, therapeutic failure frequently appears as distant metastases suggesting the need for complementary systemic therapy using new treatment modalities, particularly chemotherapy. (author)

  9. Advantages and implications of high dose rate (HDR) total skin electron irradiation (TSEI) for the management of Mycosis Fungoides. Indian experience.

    Science.gov (United States)

    Parida, Dillip Kumar; Rath, Goura Kishore

    2014-03-01

    Mycosis Fungoides (MF) is an indolent lymphoproliferative disorder affecting dermis caused by abnormal proliferation of CD4+ T-cells. Radiation therapy is the most effective modality of treatment for MF which offers cure in limited stage disease and desirable palliation in advance stage disease. Treating entire skin having many curved surfaces and folds with radiation is the real challenge for the radiation oncologist. Many techniques, dose schedules and modifications in total skin electron irradiation (TSEI) have been tried since 1950s. TSEI treatment is a very time consuming, inconvenient and physically challenging to both patient as well as oncologist. At our center TSEI was performed since 1983 with conventional linear accelerator where the treatment time was prolonged beyond two hours, which was very difficult or the patient, oncologist, technical officer and eating away the machine time hampering the treatment of other patients. From 1998 we shifted to high dose rate (HDR) mode, in order to bring down the treatment time of a single patient every day from two and half hour to 15 min. The reduction of treatment time increases patient compliance and at the same time saved machine time. Between 1998 and 2003, eleven pathological diagnosed MF patients were treated using HDR TSEI. All the patients were male between 40 and 70 years of age, who had the history of having the disease for 7-22 months. Four patients had T2 and seven patients had T3 stage disease with more than 90% skin surface involvement. TSEI was performed with 4 MeV electrons with a daily fraction size of 120 cGy to a total dose of 36 Gy. At the end of 36 Gy, boost dose of 10 Gy was delivered to self shielding regions like sole, scalp and perineum. Considering the treatment related toxicities and consequent treatment interruptions, in the first seven patients, the last four patients were treated using similar HDR TSEI technique with modified treatment schedule, where the treatment was given on

  10. SU-E-P-38: Comparison of Capri Applicator HDR Planning Methods to Meet the NCCN Uterine Neoplasm 2.2015 Guidelines

    Energy Technology Data Exchange (ETDEWEB)

    Klash, S; Steinman, J [Radphys Oncology Services, LLC, Knoxville, TN (United States); Stanley, T [CCS Oncology Center, Kenmore, NY (United States); Kim, D; Yi, S [CCS Oncology, Williamsville, NY (United States); Yap, J [CCS Oncology, Williamsville, New York (United States)

    2015-06-15

    Purpose: To establish a systematic planning approach for Capri intravaginal multichannel balloon applicators that meet updated Version 2.2015 NCCN guidelines for uterine neoplasms, which dictate delivery of 400 to 600 cGy in 2 to 3 fractions prescribed to the vaginal mucosa for HDR combined with EBRT as well as a regimen of 600 cGy x 5 (to the vaginal mucosa) for HDR brachytherapy alone. Methods: Studies have shown three different channel configurations of the Capri applicator are optimal for dosimetric conformity: central channel combined with the six inner ring channels (R12), all inner and outer ring channels (R23), or all thirteen channels (R123). To minimize the dose to the vaginal mucosa, a traditional 0.5cm expansion contour from the Capri surface was created. Optimization limits were set to push 600 cGy to 100% of the Capri volume, while simultaneously restricting dose to the expansion contour. Results: Plans were created using all three configurations (R12, R23, R123) and evaluated to determine which was best for delivering 600 cGy to the vaginal mucosa. Our criteria was: Capri V100 > 98%, Vaginal Mucosa Dmax < 125%, Bladder Dmax < 100%, Rectum Dmax < 100%. All configurations show Capri V100 values greater than 98.5%, with differences between plans varying by less than 1%. Vaginal mucosal Dmax values showed differences of roughly 5% of prescription. The R12 configuration proved the lowest vaginal mucosa Dmax, on average. The OAR Dmax values showed an average dose difference of roughly 2% of prescription, with the R23 configuration having the best results. Conclusion: The R12 channel configuration optimally fits our planning criteria and NCCN guidelines for 600 cGy prescribed to the vaginal mucosa. On average, it produced the highest Capri V100, the lowest vaginal mucosal Dmax, and a marginally higher OAR Dmax doses compared to the R23 and R123 plans.

  11. Identifying afterloading PDR and HDR brachytherapy errors using real-time fiber-coupled Al(2)O(3):C dosimetry and a novel statistical error decision criterion.

    Science.gov (United States)

    Kertzscher, Gustavo; Andersen, Claus E; Siebert, Frank-André; Nielsen, Søren Kynde; Lindegaard, Jacob C; Tanderup, Kari

    2011-09-01

    The feasibility of a real-time in vivo dosimeter to detect errors has previously been demonstrated. The purpose of this study was to: (1) quantify the sensitivity of the dosimeter to detect imposed treatment errors under well controlled and clinically relevant experimental conditions, and (2) test a new statistical error decision concept based on full uncertainty analysis. Phantom studies of two gynecological cancer PDR and one prostate cancer HDR patient treatment plans were performed using tandem ring applicators or interstitial needles. Imposed treatment errors, including interchanged pairs of afterloader guide tubes and 2-20mm source displacements, were monitored using a real-time fiber-coupled carbon doped aluminum oxide (Al(2)O(3):C) crystal dosimeter that was positioned in the reconstructed tumor region. The error detection capacity was evaluated at three dose levels: dwell position, source channel, and fraction. The error criterion incorporated the correlated source position uncertainties and other sources of uncertainty, and it was applied both for the specific phantom patient plans and for a general case (source-detector distance 5-90 mm and position uncertainty 1-4mm). Out of 20 interchanged guide tube errors, time-resolved analysis identified 17 while fraction level analysis identified two. Channel and fraction level comparisons could leave 10mm dosimeter displacement errors unidentified. Dwell position dose rate comparisons correctly identified displacements ≥ 5mm. This phantom study demonstrates that Al(2)O(3):C real-time dosimetry can identify applicator displacements ≥ 5mm and interchanged guide tube errors during PDR and HDR brachytherapy. The study demonstrates the shortcoming of a constant error criterion and the advantage of a statistical error criterion. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  12. Evaluation of hybrid inverse planning and optimization (HIPO) algorithm for optimization in real-time, high-dose-rate (HDR) brachytherapy for prostate.

    Science.gov (United States)

    Pokharel, Shyam; Rana, Suresh; Blikenstaff, Joseph; Sadeghi, Amir; Prestidge, Bradley

    2013-07-08

    The purpose of this study is to investigate the effectiveness of the HIPO planning and optimization algorithm for real-time prostate HDR brachytherapy. This study consists of 20 patients who underwent ultrasound-based real-time HDR brachytherapy of the prostate using the treatment planning system called Oncentra Prostate (SWIFT version 3.0). The treatment plans for all patients were optimized using inverse dose-volume histogram-based optimization followed by graphical optimization (GRO) in real time. The GRO is manual manipulation of isodose lines slice by slice. The quality of the plan heavily depends on planner expertise and experience. The data for all patients were retrieved later, and treatment plans were created and optimized using HIPO algorithm with the same set of dose constraints, number of catheters, and set of contours as in the real-time optimization algorithm. The HIPO algorithm is a hybrid because it combines both stochastic and deterministic algorithms. The stochastic algorithm, called simulated annealing, searches the optimal catheter distributions for a given set of dose objectives. The deterministic algorithm, called dose-volume histogram-based optimization (DVHO), optimizes three-dimensional dose distribution quickly by moving straight downhill once it is in the advantageous region of the search space given by the stochastic algorithm. The PTV receiving 100% of the prescription dose (V100) was 97.56% and 95.38% with GRO and HIPO, respectively. The mean dose (D(mean)) and minimum dose to 10% volume (D10) for the urethra, rectum, and bladder were all statistically lower with HIPO compared to GRO using the student pair t-test at 5% significance level. HIPO can provide treatment plans with comparable target coverage to that of GRO with a reduction in dose to the critical structures.

  13. SU-F-T-29: The Important of Each Fraction Image-Guided Planning for Postoperative HDR-Brachytherapy in Endometrial Carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Piriyasang, D; Pattaranutaporn, P; Manokhoon, K [Ramathibodi Hospital, Rachatewi, Bangkok (Thailand)

    2016-06-15

    Purpose: Cylindrical applicators are often used for postoperative HDRbrachytherapy in endometrial carcinoma. It has been considered that dosimetric variation between fractions for this treatment is minimal and might not be necessary to perform treatment planning for every fractions. At our institute, it is traditional to perform treatment planning with CT simulation on the first fraction and uses this plan for the rest of treatment. This study was aim to evaluate the errors of critical structure doses between the fractions when simulation and planning were done for first fraction only. Methods: Treatment plans of 10 endometrial carcinoma patients who received postoperative HDR-brachytherapy and underwent CT-simulation for every HDR-fractions at our department were retrospectively reviewed. All of these patients were treated with cylindrical applicator and prescribed dose 15Gy in 3 fractions to 0.5cm from vaginal surface. The treatment plan from the first fraction was used to simulate in second and third CT-simulation. Radiation dose for critical structures in term of Dose-to-2cc (D2cc) were evaluated and compared between planning CT. Results: The D2cc for bladder and rectum were evaluated. For bladder, the mean error of D2cc estimation for second and third fractions was 7.6% (0.1–20.1%, SD=5.7). And the mean error for D2cc of rectum was 8.5% (0.1–29.4%, SD=8.5). Conclusion: The critical structure doses could be significant difference between fractions which may affects treatment outcomes or toxicities. From our data, image-guided brachytherapy at least with CT-Simulation should be done for every treatment fractions.

  14. Quality of life in non-early rectal cancer treated by neoadjuvant radio-chemotherapy and endoluminal loco-regional resection (ELRR) by transanal endoscopic microsurgery (TEM) versus laparoscopic total mesorectal excision.

    Science.gov (United States)

    D'Ambrosio, Giancarlo; Paganini, Alessandro M; Balla, Andrea; Quaresima, Silvia; Ursi, Pietro; Bruzzone, Paolo; Picchetto, Andrea; Mattei, Fabrizio I; Lezoche, Emanuele

    2016-02-01

    In selected patients with N0 rectal cancer, endoluminal loco-regional resection (ELRR) by transanal endoscopic microsurgery (TEM) may be an alternative treatment option to laparoscopic total mesorectal excision (LTME). Aim of this study is to evaluate the short- and medium-term quality of life (QoL) from a retrospective analysis of prospectively collected data in patients with iT2-iT3 N0-N+ rectal cancer, who underwent ELRR by TEM or LTME after neoadjuvant radio-chemotherapy (n-RCT). Thirty patients with iT2-iT3 rectal cancer who underwent ELRR by TEM (n = 15) or LTME (n = 15) were enrolled in this study. The choice for one operation or the other was made on the basis of predefined criteria. QoL was evaluated by EORTC QLQ-C30 and QLQ-CR38 questionnaires at admission, after n-RCT and 1, 6, and 12 months after surgery. No statistically significant differences in QoL evaluation were observed between the two groups, both at admission and after n-RCT. At 1 month after surgery, significantly better results in the ELRR group were observed by QLQ-C30 in: Nausea/Vomiting (p = 0.05), Appetite Loss (p = 0.003), Constipation (p = 0.05), and by QLQ-CR38 in: Body Image (p = 0.05), Sexual Functioning (p = 0.03), Future Perspective (p = 0.05) and Weight Loss (p = 0.036). At 6 months after surgery, a statistically significant worse impact after LTME was observed by QLQ-C30 in: Global Health Status (p = 0.05), Emotional Functioning (p = 0.021), Dyspnea (p = 0.008), Insomnia (p = 0.012), Appetite Loss (p = 0.014) and by QLQ-CR38 in Body Image (p = 0.05) and Defecation Problems (p = 0.001). At 1 year, the two groups were homogenous as assessed by QLQ-C30, whereas the QLQ-CR38 still showed better results of ELRR versus LTME in Body Image (p = 0.006), Defecation Problems (p = 0.01), and Weight Loss (p = 0.005). Based on the present series, in selected patients, earlier restoration of patients' functions is observed after ELRR by TEM than after LTME.

  15. Watershed Boundaries, HDR engineering consulting company conducted stormwater master plan and gave us the dataset.ArcHydro can create watersheds using DEM and ArcGIS Spatial Analyst., Published in 2010, 1:600 (1in=50ft) scale, City of Decatur Government.

    Data.gov (United States)

    NSGIC Local Govt | GIS Inventory — Watershed Boundaries dataset current as of 2010. HDR engineering consulting company conducted stormwater master plan and gave us the dataset.ArcHydro can create...

  16. A multicenter study to quantify systematic variations and associated uncertainties in source positioning with commonly used HDR afterloaders and ring applicators for the treatment of cervical carcinomas

    Energy Technology Data Exchange (ETDEWEB)

    Awunor, O., E-mail: onuora.awunor@stees.nhs.uk [The Medical Physics Department, The James Cook University Hospital, Marton Road, Middlesbrough TS4 3BW, England (United Kingdom); Berger, D. [Department of Radiotherapy, General Hospital of Vienna, Vienna A-1090 (Austria); Kirisits, C. [Department of Radiotherapy, Comprehensive Cancer Center, Medical University of Vienna, Vienna A-1090 (Austria)

    2015-08-15

    Purpose: The reconstruction of radiation source position in the treatment planning system is a key part of the applicator reconstruction process in high dose rate (HDR) brachytherapy treatment of cervical carcinomas. The steep dose gradients, of as much as 12%/mm, associated with typical cervix treatments emphasize the importance of accurate and precise determination of source positions. However, a variety of methodologies with a range in associated measurement uncertainties, of up to ±2.5 mm, are currently employed by various centers to do this. In addition, a recent pilot study by Awunor et al. [“Direct reconstruction and associated uncertainties of {sup 192}Ir source dwell positions in ring applicators using gafchromic film in the treatment planning of HDR brachytherapy cervix patients,” Phys. Med. Biol. 58, 3207–3225 (2013)] reported source positional differences of up to 2.6 mm between ring sets of the same type and geometry. This suggests a need for a comprehensive study to assess and quantify systematic source position variations between commonly used ring applicators and HDR afterloaders across multiple centers. Methods: Eighty-six rings from 20 European brachytherapy centers were audited in the form of a postal audit with each center collecting the data independently. The data were collected by setting up the rings using a bespoke jig and irradiating gafchromic films at predetermined dwell positions using four afterloader types, MicroSelectron, Flexitron, GammaMed, and MultiSource, from three manufacturers, Nucletron, Varian, and Eckert & Ziegler BEBIG. Five different ring types in six sizes (Ø25–Ø35 mm) and two angles (45° and 60°) were used. Coordinates of irradiated positions relative to the ring center were determined and collated, and source position differences quantified by ring type, size, and angle. Results: The mean expanded measurement uncertainty (k = 2) along the direction of source travel was ±1.4 mm. The standard deviation

  17. SU-E-T-509: Inter-Observer and Inter-Modality Contouring Analysis for Organs at Risk for HDR Gynecological Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Sadeghi, P; Smith, W [University of Calgary, Calgary, AB (Canada); Tom Baker Cancer Centre, Calgary, AB (Canada); Banerjee, R; Alghamdi, M; Phan, T; Taggar, A [University of Calgary, Calgary, AB (Canada)

    2015-06-15

    Purpose This study quantifies errors associated with MR-guided High Dose Rate (HDR) gynecological brachytherapy. Uncertainties in this treatment results from contouring, organ motion between imaging and treatment delivery, dose calculation, and dose delivery. We focus on interobserver and inter-modality variability in contouring and the motion of organs at risk (OARs) in the time span between the MR and CT scans (∼1 hour). We report the change in organ volume and position of center of mass (CM) between the two imaging modalities. Methods A total of 8 patients treated with MR-guided HDR brachytherapy were included in this study. Two observers contoured the bladder and rectum on both MR and CT scans. The change in OAR volume and CM position between the MR and CT imaging sessions on both image sets were calculated. Results The absolute mean bladder volume change between the two imaging modalities is 67.1cc. The absolute mean inter-observer difference in bladder volume is much lower at 15.5cc (MR) and 11.0cc (CT). This higher inter-modality volume difference suggests a real change in the bladder filling between the two imaging sessions. Change in Rectum volume inter-observer standard error of means (SEM) is 3.18cc (MR) and 3.09cc (CT), while the inter-modality SEM is 3.65cc (observer 1), and 2.75cc (observer 2). The SEM for rectum CM position in the superior-inferior direction was approximately three times higher than in other directions for both the inter—observer (0.77 cm, 0.92 cm for observers 1 and 2, respectively) and inter-modality (0.91 cm, 0.95 cm for MR and CT, respectively) variability. Conclusion Bladder contours display good consistency between different observers on both CT and MR images. For rectum contouring the highest inconsistency stems from the observers’ choice of the superior-inferior borders. A complete analysis of a larger patient cohort will enable us to separate the true organ motion from the inter-observer variability.

  18. Thermal dosimetry analysis combined with patient-specific thermal modeling of clinical interstitial ultrasound hyperthermia integrated within HDR brachytherapy for treatment of locally advanced prostate cancer

    Science.gov (United States)

    Salgaonkar, Vasant A.; Wootton, Jeff; Prakash, Punit; Scott, Serena; Hsu, I. C.; Diederich, Chris J.

    2017-03-01

    This study presents thermal dosimetry analysis from clinical treatments where ultrasound hyperthermia (HT) was administered following high-dose rate (HDR) brachytherapy treatment for locally advanced prostate cancer as part of a clinical pilot study. HT was administered using ultrasound applicators from within multiple 13-g brachytherapy catheters implanted along the posterior periphery of the prostate. The heating applicators were linear arrays of sectored tubular transducers (˜7 MHz), with independently powered array elements enabling energy deposition with 3D spatial control. Typical heat treatments employed time-averaged peak acoustic intensities of 1 - 3 W/cm2 and lasted for 60 - 70 minutes. Throughout the treatments, temperatures at multiple points were monitored using multi-junction thermocouples, placed within available brachytherapy catheters throughout mid-gland prostate and identified as the hyperthermia target volume (HTV). Clinical constraints allowed placement of 8 - 12 thermocouple sensors in the HTV and patient-specific 3D thermal modeling based on finite element methods (FEM) was used to supplement limited thermometry. Patient anatomy, heating device positions, orientations, and thermometry junction locations were obtained from patient CT scans and HDR and hyperthermia planning software. The numerical models utilized the applied power levels recorded during the treatments. Tissue properties such as perfusion and acoustic absorption were varied within physiological ranges such that squared-errors between measured and simulated temperatures were minimized. This data-fitting was utilized for 6 HT treatments to estimate volumetric temperature distributions achieved in the HTV and surrounding anatomy devoid of thermocouples. For these treatments, the measured and simulated T50 values in the hyperthermia target volume (HTV) were between 40.1 - 43.9 °C and 40.3 - 44.9 °C, respectively. Maximum temperatures between 46.8 - 49.8 °C were measured during

  19. SU-G-TeP1-01: A Simulation Study to Investigate Maximum Allowable Deformations of Implant Geometry Before Plan Objectives Are Violated in Prostate HDR Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Babier, A [Department of Physics, Engineering Physics and Astronomy, Queens University, Kingston, Ontario (Canada); Joshi, C [Department of Physics, Engineering Physics and Astronomy, Queens University, Kingston, Ontario (Canada); Cancer Center of Southeastern Ontario, Kingston General Hospital, Kingston, Ontario (Canada)

    2016-06-15

    Purpose: In prostate HDR brachytherapy dose distributions are highly sensitive to changes in prostate volume and catheter displacements. We investigate the maximum deformations in implant geometry before planning objectives are violated. Methods: A typical prostate Ir-192 HDR brachytherapy reference plan was calculated on the Oncentra planning system, which used CT images from a tissue equivalent prostate phantom (CIRS Model 053S) embedded inside a pelvis wax phantom. The prostate was deformed and catheters were displaced in simulations using a code written in MATLAB. For each deformation dose distributions were calculated, based on TG43 methods, using the MATLAB code. The calculations were validated through comparison with Oncentra calculations for the reference plan, and agreed within 0.12%SD and 0.3%SD for dose and volume, respectively. Isotropic prostate volume deformations of up to +34% to −27% relative to its original volume, and longitudinal catheter displacements of 7.5 mm in superior and inferior directions were simulated. Planning objectives were based on American Brachytherapy Society guidelines for prostate and urethra volumes. A plan violated the planning objectives when less than 90% of the prostate volume received the prescribed dose or higher (V{sub 100}), or the urethral volume receiving 125% of prescribed dose or higher was more than 1 cc (U{sub 125}). Lastly, the dose homogeneity index (DHI=1-V{sub 150}/V{sub 100}) was evaluated; a plan was considered sub-optimal when the DHI fell below 0.62. Results and Conclusion: Planning objectives were violated when the prostate expanded by 10.7±0.5% or contracted by 11.0±0.2%; objectives were also violated when catheters were displaced by 4.15±0.15 mm and 3.70±0.15 mm in the superior and inferior directions, respectively. The DHI changes did not affect the plan optimality, except in the case of prostate compression. In general, catheter displacements have a significantly larger impact on plan

  20. A method for verification of treatment delivery in HDR prostate brachytherapy using a flat panel detector for both imaging and source tracking

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Ryan L., E-mail: ryan.smith@wbrc.org.au; Millar, Jeremy L.; Franich, Rick D. [Alfred Health Radiation Oncology, The Alfred Hospital, Melbourne, VIC 3004, Australia and School of Science, RMIT University, Melbourne, VIC 3000 (Australia); Haworth, Annette [School of Science, RMIT University, Melbourne, VIC 3000, Australia and Physical Sciences, Peter MacCallum Cancer Centre, East Melbourne, VIC 3002 (Australia); Panettieri, Vanessa [Alfred Health Radiation Oncology, The Alfred Hospital, Melbourne, VIC 3004 (Australia)

    2016-05-15

    Purpose: Verification of high dose rate (HDR) brachytherapy treatment delivery is an important step, but is generally difficult to achieve. A technique is required to monitor the treatment as it is delivered, allowing comparison with the treatment plan and error detection. In this work, we demonstrate a method for monitoring the treatment as it is delivered and directly comparing the delivered treatment with the treatment plan in the clinical workspace. This treatment verification system is based on a flat panel detector (FPD) used for both pre-treatment imaging and source tracking. Methods: A phantom study was conducted to establish the resolution and precision of the system. A pretreatment radiograph of a phantom containing brachytherapy catheters is acquired and registration between the measurement and treatment planning system (TPS) is performed using implanted fiducial markers. The measured catheter paths immediately prior to treatment were then compared with the plan. During treatment delivery, the position of the {sup 192}Ir source is determined at each dwell position by measuring the exit radiation with the FPD and directly compared to the planned source dwell positions. Results: The registration between the two corresponding sets of fiducial markers in the TPS and radiograph yielded a registration error (residual) of 1.0 mm. The measured catheter paths agreed with the planned catheter paths on average to within 0.5 mm. The source positions measured with the FPD matched the planned source positions for all dwells on average within 0.6 mm (s.d. 0.3, min. 0.1, max. 1.4 mm). Conclusions: We have demonstrated a method for directly comparing the treatment plan with the delivered treatment that can be easily implemented in the clinical workspace. Pretreatment imaging was performed, enabling visualization of the implant before treatment delivery and identification of possible catheter displacement. Treatment delivery verification was performed by measuring the

  1. Validation of a novel robot-assisted 3DUS system for real-time planning and guidance of breast interstitial HDR brachytherapy.

    Science.gov (United States)

    Poulin, Eric; Gardi, Lori; Barker, Kevin; Montreuil, Jacques; Fenster, Aaron; Beaulieu, Luc

    2015-12-01

    In current clinical practice, there is no integrated 3D ultrasound (3DUS) guidance system clinically available for breast brachytherapy. In this study, the authors present a novel robot-assisted 3DUS system for real-time planning and guidance of breast interstitial high dose rate (HDR) brachytherapy treatment. For this work, a new computer controlled robotic 3DUS system was built to perform a hybrid motion scan, which is a combination of a 6 cm linear translation with a 30° rotation at both ends. The new 3DUS scanner was designed to fit on a modified Kuske assembly, keeping the current template grid configuration but modifying the frame to allow the mounting of the 3DUS system at several positions. A finer grid was also tested. A user interface was developed to perform image reconstruction, semiautomatic segmentation of the surgical bed as well as catheter reconstruction and tracking. A 3D string phantom was used to validate the geometric accuracy of the reconstruction. The volumetric accuracy of the system was validated with phantoms using magnetic resonance imaging (MRI) and computed tomography (CT) images. In order to accurately determine whether 3DUS can effectively replace CT for treatment planning, the authors have compared the 3DUS catheter reconstruction to the one obtained from CT images. In addition, in agarose-based phantoms, an end-to-end procedure was performed by executing six independent complete procedures with both 14 and 16 catheters, and for both standard and finer Kuske grids. Finally, in phantoms, five end-to-end procedures were performed with the final CT planning for the validation of 3DUS preplanning. The 3DUS acquisition time is approximately 10 s. A paired Student t-test showed that there was no statistical significant difference between known and measured values of string separations in each direction. Both MRI and CT volume measurements were not statistically different from 3DUS volume (Student t-test: p > 0.05) and they were

  2. A method for verification of treatment delivery in HDR prostate brachytherapy using a flat panel detector for both imaging and source tracking.

    Science.gov (United States)

    Smith, Ryan L; Haworth, Annette; Panettieri, Vanessa; Millar, Jeremy L; Franich, Rick D

    2016-05-01

    Verification of high dose rate (HDR) brachytherapy treatment delivery is an important step, but is generally difficult to achieve. A technique is required to monitor the treatment as it is delivered, allowing comparison with the treatment plan and error detection. In this work, we demonstrate a method for monitoring the treatment as it is delivered and directly comparing the delivered treatment with the treatment plan in the clinical workspace. This treatment verification system is based on a flat panel detector (FPD) used for both pre-treatment imaging and source tracking. A phantom study was conducted to establish the resolution and precision of the system. A pretreatment radiograph of a phantom containing brachytherapy catheters is acquired and registration between the measurement and treatment planning system (TPS) is performed using implanted fiducial markers. The measured catheter paths immediately prior to treatment were then compared with the plan. During treatment delivery, the position of the (192)Ir source is determined at each dwell position by measuring the exit radiation with the FPD and directly compared to the planned source dwell positions. The registration between the two corresponding sets of fiducial markers in the TPS and radiograph yielded a registration error (residual) of 1.0 mm. The measured catheter paths agreed with the planned catheter paths on average to within 0.5 mm. The source positions measured with the FPD matched the planned source positions for all dwells on average within 0.6 mm (s.d. 0.3, min. 0.1, max. 1.4 mm). We have demonstrated a method for directly comparing the treatment plan with the delivered treatment that can be easily implemented in the clinical workspace. Pretreatment imaging was performed, enabling visualization of the implant before treatment delivery and identification of possible catheter displacement. Treatment delivery verification was performed by measuring the source position as each dwell was delivered

  3. Prostate Specific Antigen (PSA as Predicting Marker for Clinical Outcome and Evaluation of Early Toxicity Rate after High-Dose Rate Brachytherapy (HDR-BT in Combination with Additional External Beam Radiation Therapy (EBRT for High Risk Prostate Cancer

    Directory of Open Access Journals (Sweden)

    Thorsten H. Ecke

    2016-11-01

    Full Text Available High-dose-rate brachytherapy (HDR-BT with external beam radiation therapy (EBRT is a common treatment option for locally advanced prostate cancer (PCa. Seventy-nine male patients (median age 71 years, range 50 to 79 with high-risk PCa underwent HDR-BT following EBRT between December 2009 and January 2016 with a median follow-up of 21 months. HDR-BT was administered in two treatment sessions (one week interval with 9 Gy per fraction using a planning system and the Ir192 treatment unit GammaMed Plus iX. EBRT was performed with CT-based 3D-conformal treatment planning with a total dose administration of 50.4 Gy with 1.8 Gy per fraction and five fractions per week. Follow-up for all patients was organized one, three, and five years after radiation therapy to evaluate early and late toxicity side effects, metastases, local recurrence, and prostate-specific antigen (PSA value measured in ng/mL. The evaluated data included age, PSA at time of diagnosis, PSA density, BMI (body mass index, Gleason score, D’Amico risk classification for PCa, digital rectal examination (DRE, PSA value after one/three/five year(s follow-up (FU, time of follow-up, TNM classification, prostate volume, and early toxicity rates. Early toxicity rates were 8.86% for gastrointestinal, and 6.33% for genitourinary side effects. Of all treated patients, 84.81% had no side effects. All reported complications in early toxicity were grade 1. PSA density at time of diagnosis (p = 0.009, PSA on date of first HDR-BT (p = 0.033, and PSA on date of first follow-up after one year (p = 0.025 have statistical significance on a higher risk to get a local recurrence during follow-up. HDR-BT in combination with additional EBRT in the presented design for high-risk PCa results in high biochemical control rates with minimal side-effects. PSA is a negative predictive biomarker for local recurrence during follow-up. A longer follow-up is needed to assess long-term outcome and toxicities.

  4. Prostate Specific Antigen (PSA) as Predicting Marker for Clinical Outcome and Evaluation of Early Toxicity Rate after High-Dose Rate Brachytherapy (HDR-BT) in Combination with Additional External Beam Radiation Therapy (EBRT) for High Risk Prostate Cancer.

    Science.gov (United States)

    Ecke, Thorsten H; Huang-Tiel, Hui-Juan; Golka, Klaus; Selinski, Silvia; Geis, Berit Christine; Koswig, Stephan; Bathe, Katrin; Hallmann, Steffen; Gerullis, Holger

    2016-11-10

    High-dose-rate brachytherapy (HDR-BT) with external beam radiation therapy (EBRT) is a common treatment option for locally advanced prostate cancer (PCa). Seventy-nine male patients (median age 71 years, range 50 to 79) with high-risk PCa underwent HDR-BT following EBRT between December 2009 and January 2016 with a median follow-up of 21 months. HDR-BT was administered in two treatment sessions (one week interval) with 9 Gy per fraction using a planning system and the Ir192 treatment unit GammaMed Plus iX. EBRT was performed with CT-based 3D-conformal treatment planning with a total dose administration of 50.4 Gy with 1.8 Gy per fraction and five fractions per week. Follow-up for all patients was organized one, three, and five years after radiation therapy to evaluate early and late toxicity side effects, metastases, local recurrence, and prostate-specific antigen (PSA) value measured in ng/mL. The evaluated data included age, PSA at time of diagnosis, PSA density, BMI (body mass index), Gleason score, D'Amico risk classification for PCa, digital rectal examination (DRE), PSA value after one/three/five year(s) follow-up (FU), time of follow-up, TNM classification, prostate volume, and early toxicity rates. Early toxicity rates were 8.86% for gastrointestinal, and 6.33% for genitourinary side effects. Of all treated patients, 84.81% had no side effects. All reported complications in early toxicity were grade 1. PSA density at time of diagnosis (p = 0.009), PSA on date of first HDR-BT (p = 0.033), and PSA on date of first follow-up after one year (p = 0.025) have statistical significance on a higher risk to get a local recurrence during follow-up. HDR-BT in combination with additional EBRT in the presented design for high-risk PCa results in high biochemical control rates with minimal side-effects. PSA is a negative predictive biomarker for local recurrence during follow-up. A longer follow-up is needed to assess long-term outcome and toxicities.

  5. Endoluminal treatment of thoracic aortic lesions

    African Journals Online (AJOL)

    Enrique

    20 The predominant predictors ... age, chronic obstructive pulmonary disease and an elevated mean blood pressure increase the risk of ... disease, dissection or aortic rupture require immediate diagnostic evalua- tion and pre-procedural ...

  6. Endoluminal release of ureteral ligature after hysterectomy

    Directory of Open Access Journals (Sweden)

    Chih-Jen Wang

    2016-01-01

    Full Text Available Iatrogenic ureteral injury is a well-recognized complication of abdominal total hysterectomy. We report a case of a 57-year-old female who underwent abdominal total hysterectomy for a uterine myoma and experienced severe right flank pain postoperatively. The imaging study displayed an obstruction of the right distal ureter. Under ureteroscopy, an extraluminal ligature was released with a holmium:yttrium–aluminum–garnet laser. The stenotic segment was immediately relieved. Two months later, the intravenous urogram illustrated patency of the distal ureter with regression of right hydronephrosis. There was no recurrent hydronephrosis during 1 year of follow-up.

  7. Endoluminal magnetic resonance imaging in fecal incontinence

    NARCIS (Netherlands)

    E. Rociu (Elena)

    2000-01-01

    textabstractFecal incontinence is a chronic disability, has serious emotional impact and increased risk for social isolation. Imaging has become important in the diagnostic work-up of fecal incontinence. The research described in this thesis continues the line of efforts to improve the quality and

  8. Radiolesão vascular como efeito deletério da braquiterapia intra-arterial com dose elevada de Samário-153 em coelhos hipercolesterolêmicos Vascular radiolesion as a deleterious effect of high-dose-rate intraarterial brachytherapy with Samarium-153 in hypercholesterolemic rabbits

    Directory of Open Access Journals (Sweden)

    Dalton Bertolim Précoma

    2006-10-01

    Full Text Available OBJETIVO: Este estudo tem por objetivo avaliar as alterações vasculares morfológicas e morfométricas induzidas pela braquiterapia com Samário-153 (153 Sm em coelhos hipercolesterolêmicos, com doses elevadas. MÉTODOS: Foram analisados 43 coelhos hipercolesterolêmicos, brancos, da raça New Zealand, e o total de 86 artérias ilíacas submetidas a lesão por balão de angioplastia. Divididos em três grupos: dois (GI irradiados com as doses de 15Gy (n=14 e 60Gy (n=36 e um grupo controle (n=36. Foram realizadas avaliação histológica morfométrica e análise histológica qualitativa para análise tecidual. RESULTADOS: Foram observadas uma redução significativa da neoproliferação intimal (NPI no GI 15 Gy (pOBJECTIVE: This study was designed to evaluate vascular morphological and morphometric changes induced by brachytherapy with samarium-153 (Sm-153 at high doses in hypercholesterolemic rabbits. METHODS: Forty-three New Zealand White hypercholesterolemic rabbits were analyzed, and the total of 86 iliac arteries underwent balloon angioplasty injury. The rabbits were divided into three different groups: two irradiation groups (IG assigned to 15 Gy (n=14 and 60 Gy (n=36 irradiation doses, respectively, and a control group (n = 36. Histomorphometric and qualitative histological analyses were performed for tissue evaluation. RESULTS: Significant reductions were found in neointimal proliferation (NIP (p< 0.0001, media area (MA (p<0.0001 and percent stenosis (p<0.0001 in the 15-Gy IG, compared to the other groups. The 60-Gy IG had the higher rate of NIP, increase in media and vessel areas (VA and percent stenosis. The 60-Gy IG also showed the greatest number of xanthomatous cells (60-Gy IG: 86.11% and 15-Gy IG: 14.29%, p<0.0001 and the highest amount of hyaline amorphous tissue (60-Gy IG:58.33% and 15-Gy IG:0%, p=0.0001 and vascular proliferation (60-Gy IG:30.56% and 15-Gy IG:0%, p=0.0221. No statistically significant differences were found

  9. Comparison of organ doses for patients undergoing balloon brachytherapy of the breast with HDR {sup 192}Ir or electronic sources using Monte Carlo simulations in a heterogeneous human phantom

    Energy Technology Data Exchange (ETDEWEB)

    Mille, Matthew M.; Xu, X. George; Rivard, Mark J. [Nuclear Engineering and Engineering Physics Program, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts 02111 (United States)

    2010-02-15

    Purpose: Accelerated partial breast irradiation via interstitial balloon brachytherapy is a fast and effective treatment method for certain early stage breast cancers. The radiation can be delivered using a conventional high-dose rate (HDR) {sup 192}Ir gamma-emitting source or a novel electronic brachytherapy (eBx) source which uses lower energy x rays that do not penetrate as far within the patient. A previous study [A. Dickler, M. C. Kirk, N. Seif, K. Griem, K. Dowlatshahi, D. Francescatti, and R. A. Abrams, ''A dosimetric comparison of MammoSite high-dose-rate brachytherapy and Xoft Axxent electronic brachytherapy,'' Brachytherapy 6, 164-168 (2007)] showed that the target dose is similar for HDR {sup 192}Ir and eBx. This study compares these sources based on the dose received by healthy organs and tissues away from the treatment site. Methods: A virtual patient with left breast cancer was represented by a whole-body, tissue-heterogeneous female voxel phantom. Monte Carlo methods were used to calculate the dose to healthy organs in a virtual patient undergoing balloon brachytherapy of the left breast with HDR {sup 192}Ir or eBx sources. The dose-volume histograms for a few organs which received large doses were also calculated. Additional simulations were performed with all tissues in the phantom defined as water to study the effect of tissue inhomogeneities. Results: For both HDR {sup 192}Ir and eBx, the largest mean organ doses were received by the ribs, thymus gland, left lung, heart, and sternum which were close to the brachytherapy source in the left breast. eBx yielded mean healthy organ doses that were more than a factor of {approx}1.4 smaller than for HDR {sup 192}Ir for all organs considered, except for the three closest ribs. Excluding these ribs, the average and median dose-reduction factors were {approx}28 and {approx}11, respectively. The volume distribution of doses in nearby soft tissue organs that were outside the PTV were also

  10. Systematic Review of Focal Prostate Brachytherapy and the Future Implementation of Image-Guided Prostate HDR Brachytherapy Using MR-Ultrasound Fusion

    Directory of Open Access Journals (Sweden)

    M. Sean Peach

    2016-01-01

    Full Text Available Prostate cancer is the most common malignancy found in North American and European men and the second most common cause of cancer related death. Since the practice of PSA screening has become common the disease is most often found early and can have a long indolent course. Current definitive therapy treats the whole gland but has considerable long-term side effects. Focal therapies may be able to target the cancer while decreasing dose to organs at risk. Our objective was to determine if focal prostate brachytherapy could meet target objectives while permitting a decrease in dose to organs at risk in a way that would allow future salvage treatments. Further, we wanted to determine if focal treatment results in less toxicity. Utilizing the Medline repository, dosimetric papers comparing whole gland to partial gland brachytherapy and clinical papers that reported toxicity of focal brachytherapy were selected. A total of 9 dosimetric and 6 clinical papers met these inclusion criteria. Together, these manuscripts suggest that focal brachytherapy may be employed to decrease dose to organs at risk with decreased toxicity. Of current technology, image-guided HDR brachytherapy using MRI registered to transrectal ultrasound offers the flexibility and efficiency to achieve such focal treatments.

  11. Flow characteristic of Hijiori HDR reservoir from circulation test in 1991; Koon tantai Hijiori jikkenjo ni okeru senbu choryuso shiken (1991 nendo) kekka to ryudo kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Shiga, T.; Hyodo, M.; Shinohara, N.; Takasugi, S. [Geothermal Energy Research and Development Co. Ltd., Tokyo (Japan)

    1996-05-01

    This paper reports one example of flow analyses on a circulation test carried out in fiscal 1991 at the Hijiori hot dry rock experimental field (Yamagata Prefecture). A fluid circulation model was proposed to simulate an HDR circulation system for a shallow reservoir (at a depth of about 1800 m) demonstrated in the circulation test by using an electric circuit network (which expresses continuity impedance in resistance and fluid storage in capacitance). Storage capacity of the reservoir was estimated by deriving time constant of the system from data of time-based change in reservoir pressure associated with transition phenomena during the circulation test. The storage capacity was estimated separately by dividing change of storage in the reservoir by change in the reservoir pressure. To derive the storage in the reservoir, a method to calculate non-recovered flows in the circulation test was utilized. The results of evaluating the reservoir capacity in the shallow reservoir using the above two independent methods were found substantially consistent. 3 refs., 6 figs., 1 tab.

  12. Flow characteristics of Hijiori HDR reservoir form circulation test in 1995; Koon tantai Hijiori jikkenjo ni okeru shinbu choryuso yobi junkan shiken (1995 nendo) kekka to ryudo kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Fukushima, N.; Hyodo, M.; Shinohara, N.; Takasugi, S. [Geothermal Energy Research and Development Co. Ltd., Tokyo (Japan)

    1996-05-01

    This paper reports the result of a preliminary circulation test conducted in fiscal 1995 on a deep reservoir (at a depth of about 2200 m) in the Hijiori hot dry rock experimental field. One water injection well and two production wells were drilled to constitute a circulation loop, to which the circulation test was performed to investigate the flow characteristics thereof. The result revealed the following matters: total amount of injected water of 51500 m{sup 3} resulted in a total fluid recovery rate of about 40%; as a result of well stimulation given twice during the initial stage of the water injection, the continuity impedance in the vicinity of the injection well decreased largely (however, the continuity improvement upon the second attempt was considerably inferior to that from the first attempt); and increase in the water injection amount does not necessarily lead to increase in the production amount. The paper describes additionally that it is extremely difficult to interpret non-linearity between the injection and production amounts by using a model prepared previously with a main objective to analyze the Hijiori HDR circulation system. 1 ref., 9 figs., 1 tab.

  13. A Case of HDR Syndrome and Ichthyosis: Dual Diagnosis by Whole-Genome Sequencing of Novel Mutations in GATA3 and STS Genes.

    Science.gov (United States)

    Goodwin, Gregory; Hawley, Pamela P; Miller, David T

    2016-03-01

    Atypical presentations of complex multisystem disorders may elude diagnosis based on clinical findings only. Appropriate diagnostic tests may not be available or available tests may not provide appropriate coverage of relevant genomic regions for patients with complex phenotypes. Clinical whole-exome/-genome sequencing is often considered for complex patients lacking a definitive diagnosis. A boy who is now 7 years old presented as a newborn with congenital ichthyosis. At 6 weeks of age, he presented with failure to thrive and hypoparathyroidism. At 4 years of age, he was diagnosed with sensorineural hearing loss. Whole-genome sequencing identified novel mutations in GATA3, which causes HDR syndrome (hypoparathyroidism and deafness), and STS, which causes X -linked congenital ichthyosis. Whole-genome sequencing led to a definitive clinical diagnosis in a case where no other clinical test was available for GATA3, and no sequencing panel would have included both genes because they have disparate phenotypes. This case demonstrates the power of whole-genome (or exome) sequencing for patients with complex clinical presentations involving endocrine abnormalities.

  14. Validation of a novel robot-assisted 3DUS system for real-time planning and guidance of breast interstitial HDR brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Poulin, Eric; Beaulieu, Luc, E-mail: Luc.Beaulieu@phy.ulaval.ca [Département de Physique, de Génie Physique et d’optique et Centre de Recherche sur le Cancer de l’Université Laval, Université Laval, Québec, Québec G1V 0A6, Canada and Département de Radio-oncologie et Axe Oncologie du Centre de Recherche du CHU de Québec, CHU de Québec, 11 Côte du Palais, Québec, Québec G1R 2J6 (Canada); Gardi, Lori; Barker, Kevin; Montreuil, Jacques; Fenster, Aaron [Imaging Research Laboratories, Robarts Research Institute, 100 Perth Drive, London, Ontario N6A 5K8 (Canada)

    2015-12-15

    Purpose: In current clinical practice, there is no integrated 3D ultrasound (3DUS) guidance system clinically available for breast brachytherapy. In this study, the authors present a novel robot-assisted 3DUS system for real-time planning and guidance of breast interstitial high dose rate (HDR) brachytherapy treatment. Methods: For this work, a new computer controlled robotic 3DUS system was built to perform a hybrid motion scan, which is a combination of a 6 cm linear translation with a 30° rotation at both ends. The new 3DUS scanner was designed to fit on a modified Kuske assembly, keeping the current template grid configuration but modifying the frame to allow the mounting of the 3DUS system at several positions. A finer grid was also tested. A user interface was developed to perform image reconstruction, semiautomatic segmentation of the surgical bed as well as catheter reconstruction and tracking. A 3D string phantom was used to validate the geometric accuracy of the reconstruction. The volumetric accuracy of the system was validated with phantoms using magnetic resonance imaging (MRI) and computed tomography (CT) images. In order to accurately determine whether 3DUS can effectively replace CT for treatment planning, the authors have compared the 3DUS catheter reconstruction to the one obtained from CT images. In addition, in agarose-based phantoms, an end-to-end procedure was performed by executing six independent complete procedures with both 14 and 16 catheters, and for both standard and finer Kuske grids. Finally, in phantoms, five end-to-end procedures were performed with the final CT planning for the validation of 3DUS preplanning. Results: The 3DUS acquisition time is approximately 10 s. A paired Student t-test showed that there was no statistical significant difference between known and measured values of string separations in each direction. Both MRI and CT volume measurements were not statistically different from 3DUS volume (Student t-test: p > 0

  15. Comparison of 3D dose distributions for HDR 192Ir brachytherapy sources with normoxic polymer gel dosimetry and treatment planning system.

    Science.gov (United States)

    Senkesen, Oznur; Tezcanli, Evrim; Buyuksarac, Bora; Ozbay, Ismail

    2014-01-01

    Radiation fluence changes caused by the dosimeter itself and poor spatial resolution may lead to lack of 3-dimensional (3D) information depending on the features of the dosimeter and quality assurance of dose distributions for high-dose rate (HDR) iridium-192 ((192)Ir) brachytherapy sources is challenging and experimental dosimetry methods used for brachytherapy sources are limited. In this study, we investigated 3D dose distributions of (192)Ir brachytherapy sources for irradiation with single and multiple dwell positions using a normoxic gel dosimeter and compared them with treatment planning system (TPS) calculations. For dose calibration purposes, 100-mL gel-containing vials were irradiated at predefined doses and then scanned in an magnetic resonance (MR) imaging unit. Gel phantoms prepared in 2 spherical glasses were irradiated with (192)Ir for the calculated dwell positions, and MR scans of the phantoms were obtained. The images were analyzed with MATLAB software. Dose distributions and profiles derived with 1-mm resolution were compared with TPS calculations. Linearity was observed between the delivered dose and the reciprocal of the T2 relaxation time constant of the gel. The x-, y-, and z-axes were defined as the sagittal, coronal, and axial planes, respectively, the sagittal and axial planes were defined parallel to the long axis of the source while the coronal plane was defined horizontally to the long axis of the source. The differences between measured and calculated profile widths of 3-cm source length and point source for 70%, 50%, and 30% isodose lines were evaluated at 3 dose levels using 18 profiles of comparison. The calculations for 3-cm source length revealed a difference of > 3mm in 1 coordinate at 50% profile width on the sagittal plane and 3 coordinates at 70% profile width and 2 coordinates at 50% and 30% profile widths on the axial plane. Calculations on the coronal plane for 3-cm source length showed > 3-mm difference in 1 coordinate at

  16. SU-G-201-13: Investigation of Dose Variation Induced by HDR Ir-192 Source Global Shift Within the Varian Ring Applicator Using Monte Carlo Methods

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Y; Cai, J; Meltsner, S; Chang, Z; Craciunescu, O [Duke University Medical Center, Durham, NC (United States)

    2016-06-15

    Purpose: The Varian tandem and ring applicators are used to deliver HDR Ir-192 brachytherapy for cervical cancer. The source path within the ring is hard to predict due to the larger interior ring lumen. Some studies showed the source could be several millimeters different from planned positions, while other studies demonstrated minimal dosimetric impact. A global shift can be applied to limit the effect of positioning offsets. The purpose of this study was to assess the necessities of implementing a global source shift using Monte Carlo (MC) simulations. Methods: The MCNP5 radiation transport code was used for all MC simulations. To accommodate TG-186 guidelines and eliminate inter-source attenuation, a BrachyVision plan with 10 dwell positions (0.5cm step sizes) was simulated as the summation of 10 individual sources with equal dwell times for simplification. To simplify the study, the tandem was also excluded from the MC model. Global shifts of ±0.1, ±0.3, ±0.5 cm were then simulated as distal and proximal from the reference positions. Dose was scored in water for all MC simulations and was normalized to 100% at the normalization point 0.5 cm from the cap in the ring plane. For dose comparison, Point A was 2 cm caudal from the buildup cap and 2 cm lateral on either side of the ring axis. With seventy simulations, 108 photon histories gave a statistical uncertainties (k=1) <2% for (0.1 cm)3 voxels. Results: Compared to no global shift, average Point A doses were 0.0%, 0.4%, and 2.2% higher for distal global shifts, and 0.4%, 2.8%, and 5.1% higher for proximal global shifts, respectively. The MC Point A doses differed by < 1% when compared to BrachyVision. Conclusion: Dose variations were not substantial for ±0.3 cm global shifts, which is common in clinical practice.

  17. Radiobiological restrictions and tolerance doses of repeated single-fraction hdr-irradiation of intersecting small liver volumes for recurrent hepatic metastases

    Directory of Open Access Journals (Sweden)

    Wust Peter

    2010-05-01

    Full Text Available Abstract Background To assess radiobiological restrictions and tolerance doses as well as other toxic effects derived from repeated applications of single-fraction high dose rate irradiation of small liver volumes in clinical practice. Methods Twenty patients with liver metastases were treated repeatedly (2 - 4 times at identical or intersecting locations by CT-guided interstitial brachytherapy with varying time intervals. Magnetic resonance imaging using the hepatocyte selective contrast media Gd-BOPTA was performed before and after treatment to determine the volume of hepatocyte function loss (called pseudolesion, and the last acquired MRI data set was merged with the dose distributions of all administered brachytherapies. We calculated the BED (biologically equivalent dose for a single dose d = 2 Gy for different α/β values (2, 3, 10, 20, 100 based on the linear-quadratic model and estimated the tolerance dose for liver parenchyma D90 as the BED exposing 90% of the pseudolesion in MRI. Results The tolerance doses D90 after repeated brachytherapy sessions were found between 22 - 24 Gy and proved only slightly dependent on α/β in the clinically relevant range of α/β = 2 - 10 Gy. Variance analysis showed a significant dependency of D90 with respect to the intervals between the first irradiation and the MRI control (p 90 and the pseudolesion's volume. No symptoms of liver dysfunction or other toxic effects such as abscess formation occurred during the follow-up time, neither acute nor on the long-term. Conclusions Inactivation of liver parenchyma occurs at a BED of approx. 22 - 24 Gy corresponding to a single dose of ~10 Gy (α/β ~ 5 Gy. This tolerance dose is consistent with the large potential to treat oligotopic and/or recurrent liver metastases by CT-guided HDR brachytherapy without radiation-induced liver disease (RILD. Repeated small volume irradiation may be applied safely within the limits of this study.

  18. SU-E-T-297: Dosimetric Assessment of An Air-Filled Balloon Applicator in HDR Vaginal Cuff Brachytherapy Using the Monte Carlo Method

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, H; Lee, Y; Pokhrel, D; Badkul, R [University of Kansas Hospital, Kansas City, KS (United States)

    2015-06-15

    Purpose: As an alternative to cylindrical applicators, air inflated balloon applicators have been introduced into HDR vaginal cuff brachytherapy treatment to achieve sufficient dose to vagina mucosa as well as to spare rectum and bladder. In general, TG43 formulae based treatment planning systems do not take into account tissue inhomogeneity, and air in the balloon applicator can cause higher delivered dose to mucosa than treatment plan reported. We investigated dosimetric effect of air in balloon applicator using the Monte Carlo method. Methods: The thirteen-catheter Capri applicator with a Nucletron Ir-192 seed was modeled for various balloon diameters (2cm to 3.5cm) using the MCNP Monte Carlo code. Ir-192 seed was placed in both central and peripheral catheters to replicate real patient situations. Existence of charged particle equilibrium (CPE) with air balloon was evaluated by comparing kerma and dose at various distances (1mm to 70mm) from surface of air-filled applicator. Also mucosa dose by an air-filled applicator was compared with by a water-filled applicator to evaluate dosimetry accuracy of planning system without tissue inhomogeneity correction. Results: Beyond 1mm from air/tissue interface, the difference between kerma and dose was within 2%. CPE (or transient CPE) condition was deemed existent, and in this region no electron transport was necessary in Monte Carlo simulations. At 1mm or less, the deviation of dose from kerma became more apparent. Increase of dose to mucosa depended on diameter of air balloon. The increment of dose to mucosa was 2.5% and 4.3% on average for 2cm and 3.5cm applicators, respectively. Conclusion: After introduction of air balloon applicator, CPE fails only at the proximity of air/tissue interface. Although dose to mucosa is increased, there is no significant dosimetric difference (<5%) between air and water filled applicators. Tissue inhomogeneity correction is not necessary for air-filled applicators.

  19. Interstitial HDR-brachytherapy of unresectable pancreatic carcinoma by 3D-CT-planning in combination with external beam radiation and chemotherapy, methodology and clinical results; 3D-CT-geplante interstitielle HDR-Brachytherapie + perkutane Bestrahlung und Chemotherapie bei inoperablen Pankreaskarzinomen. Methodik und klinische Ergebnisse

    Energy Technology Data Exchange (ETDEWEB)

    Pfreundner, L.; Baier, K.; Schwab, F.; Willner, J.; Bratengeier, K.; Flentje, M. [Wuerzburg Univ. (Germany). Klinik fuer Strahlentherapie; Feustel, H. [Chirurgische Abt. der Missionsaerztlichen Klinik, Wuerzburg (Germany); Fuchs, K.H. [Chirurgische Universitaetsklinik, Wuerzburg (Germany)

    1998-03-01

    Nineteen patients (9 female, 10 male, median age 67 years) with unresectable carcinoma of the pancreas have been treated with interstitial brachytherapy. Distribution according to UICC stages showed 4, 10 and 5 patients in stage II to IV respectively. In all cases afterloading technique with 192-iridium in HDR-modus was used. A total dose of 10 to 34 Gy to the reference isodose was delivered (single dose 1.88 to 5 Gy, median 2.5 Gy). Brachytherapy was followed by external radiotherapy, delivering an additional dose of 40 to 58 Gy. Nine patients received simultaneous chemotherapy (5-fluorouracil, leucovorin). Treatment planning was performed based on CT scans, allowing spatial correlation of isodose curves to the patient`s anatomy. Median survival time was 6 months. A trend of lower survival rates with advanced stage of disease (median survival stage IV 4 months, stage II and III 6.5 months) was seen. Local control rate was 70%. Brachytherapy treatment was well tolerated, severe acute side effects were not observed. One patient developed pancreatic fistulae 4 months and 1 patient a gastric ulcer 7 months after treatment. Pain release was achieved in all patients. (orig./MG) [Deutsch] 19 Patienten (neun Frauen, zehn Maenner) mit einem inoperablen Adenokarzinom des Pankreas (UICC-Stadium IV n=5, Stadium III n=10, Stadium II n=4) im Alter von median 67 Jahren wurden mit einer interstitiellen Brachytherapie mit 192-Iridium HDR im Afterloadingverfahren behandelt. Die auf die Referenzisodose eingestrahlten Dosen lagen zwischen 10 und 34 Gy, bei Einzeldosen von 1,88 bis 5 Gy (median 2,0 Gy). Der interstitiellen Therapie schloss sich eine perkutane Radiatio mit Gesamtdosen zwischen 40 und 58 Gy an. Bei neun Patienten wurde zusaetzlich eine Chemotherapie mit 5-Fluorouracil und Leucovorin appliziert. Fuer die interstitielle Brachytherapie wurde ein CT-gestuetztes Planungsverfahren angewandt, das eine raeumliche Zuordnung der Isodosenverteilung zur Patientenanatomie gestattet

  20. Comparación de costes de tres tratamientos del cáncer de próstata localizado en España: prostatectomía radical, braquiterapia prostática y radioterapia conformacional externa 3D Cost comparison of three treatments for localized prostate cancer in Spain: radical prostatectomy, prostate brachytherapy and external 3D conformal radiotherapy

    Directory of Open Access Journals (Sweden)

    Virginia Becerra Bachino

    2011-02-01

    Full Text Available Objetivo: Comparar los costes de los tratamientos más establecidos para el cáncer de próstata localizado según grupos de riesgo, edad y comorbilidad, desde la perspectiva del proveedor asistencial. Métodos: Comparación de costes en pacientes reclutados consecutivamente entre 2003 y 2005 en una unidad funcional de tratamiento del cáncer de próstata. La utilización de servicios hasta 6 meses después del inicio del tratamiento se obtuvo de las bases de datos hospitalarias, y los costes directos se estimaron mediante cálculo microcoste. La información sobre las características clínicas de los pacientes y los tratamientos recogió prospectivamente. Los costes se compararon mediante tests no paramétricos de comparación de medianas (Kruskall-Wallis y un modelo semilogarítmico de regresión múltiple. Resultados: La diferencia de costes fue estadísticamente significativa: medianas de 3229.10 €, 5369.00 € y 6265.60 € para los pacientes tratados con radioterapia conformacional externa 3D, braquiterapia, y prostatectomía radical retropública, respectivamente (pObjective: To compare the initial costs of the three most established treatments for clinically localized prostate cancer according to risk, age and comorbidity groups, from the healthcare provider's perspective. Methods: We carried out a cost comparison study in a sample of patients consecutively recruited between 2003 and 2005 from a functional unit for prostate cancer treatment in Catalonia (Spain. The use of services up to 6 months after the treatment start date was obtained from hospital databases and direct costs were estimated by micro-cost calculation. Information on the clinical characteristics of patients and treatments was collected prospectively. Costs were compared by using nonparametric tests comparing medians (Kruskall-Wallis and a semi-logarithmic multiple regression model. Results: Among the 398 patients included, the cost difference among treatments was

  1. SU-E-T-580: On the Significance of Model Based Dosimetry for Breast and Head and Neck 192Ir HDR Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Peppa, V; Pappas, E; Pantelis, E; Papagiannis, P [Medical Physics Laboratory, Medical School, University of Athens, Athens (Greece); Major, T; Polgar, C [National Institute of Oncology, Budapest (Hungary)

    2015-06-15

    Purpose: To assess the dosimetric and radiobiological differences between TG43-based and model-based dosimetry in the treatment planning of {sup 192}Ir HDR brachytherapy for breast and head and neck cancer. Methods: Two cohorts of 57 Accelerated Partial Breast Irradiation (APBI) and 22 head and neck (H&N) patients with oral cavity carcinoma were studied. Dosimetry for the treatment plans was performed using the TG43 algorithm of the Oncentra Brachy v4.4 treatment planning system (TPS). Corresponding Monte Carlo (MC) simulations were performed using MCNP6 with input files automatically prepared by the BrachyGuide software tool from DICOM RT plan data. TG43 and MC data were compared in terms of % dose differences, Dose Volume Histograms (DVHs) and related indices of clinical interest for the Planning Target Volume (PTV) and the Organs-At-Risk (OARs). A radiobiological analysis was also performed using the Equivalent Uniform Dose (EUD), mean survival fraction (S) and Tumor Control Probability (TCP) for the PTV, and the Normal Tissue Control Probability (N TCP) and the generalized EUD (gEUD) for the OARs. Significance testing of the observed differences performed using the Wilcoxon paired sample test. Results: Differences between TG43 and MC DVH indices, associated with the increased corresponding local % dose differences observed, were statistically significant. This is mainly attributed to their consistency however, since TG43 agrees closely with MC for the majority of DVH and radiobiological parameters in both patient cohorts. Differences varied considerably among patients only for the ipsilateral lung and ribs in the APBI cohort, with a strong correlation to target location. Conclusion: While the consistency and magnitude of differences in the majority of clinically relevant DVH indices imply that no change is needed in the treatment planning practice, individualized dosimetry improves accuracy and addresses instances of inter-patient variability observed. Research

  2. Development of a fast 3D treatment planning platform for clinical interstitial microwave hyperthermia within free-hand obliquely implanted HDR catheters

    Science.gov (United States)

    Scott, Serena J.; Salgaonkar, Vasant A.; Prakash, Punit; Curto, Sergio; Hsu, I.-Chow; Diederich, Chris J.

    2015-03-01

    A treatment planning platform for interstitial microwave hyperthermia was developed for practical, free-hand clinical implants. Such implants, consisting of non-parallel, moderately curved antennas with varying insertion depths, are used in HDR brachytherapy for treating locally advanced cancer. Numerical models for commercially available MA251 antennas (915 MHz, BSD Medical) were developed in COMSOL Multiphysics, a finite element analysis software package. To expedite treatment planning, electric fields, power deposition and temperature rises were computed for a single straight antenna in 2D axisymmetric geometry. A precomputed library of electric field and temperature solutions was created for a range of insertion depths (5-12 cm) and blood perfusion rates (0.5-5 kg/m3/s). 3D models of multiple antennas and benchtop phantoms experiments using temperature-sensitive liquid crystal paper to monitor heating by curved antennas were performed for comparative evaluation of the treatment planning platform. A patient-customizable hyperthermia treatment planning software package was developed in MATLAB with capabilities to interface with a commercial radiation therapy planning platform (Oncentra, Nucleotron), import patient and multicatheter implant geometries, calculate insertion depths, and perform hyperthermia planning with antennas operating in asynchronous or synchronous mode. During asynchronous operation, the net power deposition and temperature rises were approximated as a superposition sum of the respective quantities for one single antenna. During synchronous excitation, a superposition of complex electrical fields was performed with appropriate phasing to compute power deposition. Electric fields and temperatures from the pre-computed single-antenna library were utilized following appropriate non-rigid coordinate transformations. Comparison to 3D models indicated that superposition of electric fields around parallel antennas is valid when they are at least 15 mm

  3. Measurement of absorbed dose-to-water for an HDR {sup 192}Ir source with ionization chambers in a sandwich setup

    Energy Technology Data Exchange (ETDEWEB)

    Araki, Fujio; Kouno, Tomohiro; Ohno, Takeshi [Department of Health Sciences, Faculty of Life Sciences, Kumamoto University, 4-24-1 Kuhonji, Kumamoto 862-0976 (Japan); Kakei, Kiyotaka; Yoshiyama, Fumiaki [Department of Radiotherapy, Kumamoto University Hospital, 1-1-1 Honjyo, Kumamoto 860-8556 (Japan); Kawamura, Shinji [Department of Radiotherapy, Miyazaki University Hospital, 5200 Kihara Ohaza Kiyotake-Machi, Miyazaki 889-1692 (Japan)

    2013-09-15

    Purpose: In this study, a dedicated device for ion chamber measurements of absorbed dose-to-water for a Nucletron microSelectron-v2 HDR {sup 192}Ir brachytherapy source is presented. The device uses two ionization chambers in a so-called sandwich assembly. Using this setup and by taking the average reading of the two chambers, any dose error due to difficulties in absolute positioning (centering) of the source in between the chambers is cancelled to first order. The method's accuracy was examined by comparing measurements with absorbed dose-to-water determination based on the AAPM TG-43 protocol.Methods: The optimal source-to-chamber distance (SCD) for {sup 192}Ir dosimetry was determined from ion chamber measurements in a water phantom. The {sup 192}Ir source was sandwiched between two Exradin A1SL chambers (0.057 cm{sup 3}) at the optimal SCD separation. The measured ionization was converted to the absorbed dose-to-water using a {sup 60}Co calibration factor and a Monte Carlo-calculated beam quality conversion factor, k{sub Q}, for {sup 60}Co to {sup 192}Ir. An uncertainty estimate of the proposed method was determined based on reproducibility of measurements at different institutions for the same type of source.Results: The optimal distance for the A1SL chamber measurements was determined to be 5 cm from the {sup 192}Ir source center, considering the depth dependency of k{sub Q} for {sup 60}Co to {sup 192}Ir and the chamber positioning. The absorbed dose to water measured at (5 cm, 90°) on the transverse axis was 1.3% lower than TG-43 values and its reproducibility and overall uncertainty were 0.8% and 1.7%, respectively. The measurement doses at anisotropic points agreed within 1.5% with TG-43 values.Conclusions: The ion chamber measurement of absorbed dose-to-water with a sandwich method for the {sup 192}Ir source provides a more accurate, direct, and reference dose compared to the dose-to-water determination based on air-kerma strength in the TG-43

  4. SU-E-T-433: Pear-Shaped Based Dose Optimization for HDR Intracavitary Brachytherapy for Cervical Cancer Patients with Small Uterus.

    Science.gov (United States)

    Shen, S; Kim, R; Duan, J; Wu, X; Popple, R; Cardan, R; Brezovich, I

    2012-06-01

    Currently, CT has been widely used for HDR planning as MRI is not widely available for tumor imaging. Conventional pear-shaped isodose distribution may not be discarded completely because of possible microscopic diseases into parametrium/uterus. For patients with small uterus, organs at risk (OARs) can fall inside 100% conventional pear-shaped isodose-line. This study compares two pear-shaped based dose optimization methods for OARs sparing. Seven cervical cancer patients with small uterus were evaluated using 2 methods. For Method A, with conventional dwell-time loading, point A lateral distance was reduced until all OARs' D2cc were within the dose limits. For Method B, a reference target volume was generated using conventional pear-shaped 100% isodose- surface. While isodose-line near the point A was adjusted for OARs sparing, isodose-line surrounding ovoids were optimized to match the reference target volume. For equivalent OAR sparing, 100% isodose-line width (lateral dimension) at 1 cm inferior to point A (-1 cm) and at across centers of ovoids (ovoid) were compared between the 2 methods. OARs fall inside conventional 100% isodose-line in all cases. Median position of hot spots was 0.2 cm (range -;1.2 to 2.9 cm) superior to point A. Using Method A, point A lateral distance was adjusted to 1.4-1.7 cm for OARs sparing. Median width of 100% isodose-line was 5.82 cm at ovoid level, and 4.50 cm at -1 cm level. At ovoid level, median width of 100% isodose-line was reduced by 9(8-13)% for Method A, and was unchanged for Method B. At -1 cm level, median width of 100% isodose-line was reduced by 19(2- 33)% for Method A, and 11(0-15)% for Method B. for patients with small uterus, OARs are often fall inside 100% pear-s haped isodose-line near point A level. OARs can be spared without dramatically compromise treatment volume coverage around cervix using Method B. © 2012 American Association of Physicists in Medicine.

  5. WE-A-17A-06: Evaluation of An Automatic Interstitial Catheter Digitization Algorithm That Reduces Treatment Planning Time and Provide Means for Adaptive Re-Planning in HDR Brachytherapy of Gynecologic Cancers

    Energy Technology Data Exchange (ETDEWEB)

    Dise, J [Philadelphia, PA (United States); Liang, X; Lin, L [University of Pennsylvania, Philadelphia, Pennsylvania (United States); Teo, B [University of Pennsylvania, Wayne, PA (United States)

    2014-06-15

    Purpose: To evaluate an automatic interstitial catheter digitization algorithm that reduces treatment planning time and provide means for adaptive re-planning in HDR Brachytherapy of Gynecologic Cancers. Methods: The semi-automatic catheter digitization tool utilizes a region growing algorithm in conjunction with a spline model of the catheters. The CT images were first pre-processed to enhance the contrast between the catheters and soft tissue. Several seed locations were selected in each catheter for the region growing algorithm. The spline model of the catheters assisted in the region growing by preventing inter-catheter cross-over caused by air or metal artifacts. Source dwell positions from day one CT scans were applied to subsequent CTs and forward calculated using the automatically digitized catheter positions. This method was applied to 10 patients who had received HDR interstitial brachytherapy on an IRB approved image-guided radiation therapy protocol. The prescribed dose was 18.75 or 20 Gy delivered in 5 fractions, twice daily, over 3 consecutive days. Dosimetric comparisons were made between automatic and manual digitization on day two CTs. Results: The region growing algorithm, assisted by the spline model of the catheters, was able to digitize all catheters. The difference between automatic and manually digitized positions was 0.8±0.3 mm. The digitization time ranged from 34 minutes to 43 minutes with a mean digitization time of 37 minutes. The bulk of the time was spent on manual selection of initial seed positions and spline parameter adjustments. There was no significance difference in dosimetric parameters between the automatic and manually digitized plans. D90% to the CTV was 91.5±4.4% for the manual digitization versus 91.4±4.4% for the automatic digitization (p=0.56). Conclusion: A region growing algorithm was developed to semi-automatically digitize interstitial catheters in HDR brachytherapy using the Syed-Neblett template. This automatic

  6. SU-E-T-525: Dose Volume Histograms (DVH) Analysis and Comparison with ICRU Point Doses in MRI Guided HDR Brachytherapy for Cervical Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Badkul, R; McClinton, C; Kumar, P; Mitchell, M [University of Kansas Medical Center, Kansas City, KS (United States)

    2014-06-01

    .1 overestimated the bladder ICRU point dose up to 43% for conventional-techniques.Bladder-D2 provided a good estimation of ICRU bladder point-doses(within 3.6%) for conventional-techniques. This correlation is not observed for MGO plans perhaps due to steering of isodose line, leading to unpredictable dwell-weighting. Conclusion: MRI based HDR-planning provides accurate delineation of tumor volumes and normal structures, and optimized tumor-coverage can be achieved with acceptable normal-tissue doses. This study showed that for conventional techniques D0.1 rectum dose and D2 bladder dose are good representation of ICRU-reference-point doses.

  7. Characterization of TLD-100 in powders for dosimetric quality control of {sup 192} Ir sources used in brachytherapy of high dose rate; Caracterizacion de TLD-100 en polvo para control de calidad dosimetrico de fuentes de Ir{sup 192} usadas en braquiterapia de alta tasa de dosis

    Energy Technology Data Exchange (ETDEWEB)

    Loaiza C, S.P

    2007-07-01

    The Secondary Standard Dosimetric at the National Institute of Nuclear Research (ININ) calibrated a lot of powdered TLD-100 (LiF:Mg,Ti) in terms of absorbed dose to water D{sub w} for the energy of: {sup 60}Co, {sup 137C}s, X rays of 250 and 50 kVp. Later on, it is carried out an interpolation of the calibration for the energy of the {sup 192}Ir. This calibration is part of a dosimetric quality control program, to solve the problems of traceability for the measurements carried out by the users of {sup 192}Ir sources employed in the treatments of High Dose Rate Brachytherapy (HDR) at the Mexican Republic. The calibrations of the radiation beams are made with the following protocols: IAEA TRS-398 for the {sup 60}Co for D{sub w}, using a secondary standard ionization chamber PTW N30013 calibrated in D{sub w} by the National Research Council (NRC, Canada). AAPM TG-43 for D{sub w} in terms of the strength kerma Sk, calibrating this last one quantity for the {sup 137}Cs radioactive source, with a well chamber HDR 1000 PLUS traceable to the University of Wisconsin (US). AAPM TG-61 for X ray of 250 and 50 kVp for D{sub w} start to Ka using field standard a Farmer chamber PTW 30001 traceable to K for the Central Laboratory of Electric Industries (CLEI, France). The calibration curves (CC) they built for the response of the powder TLD: R{sub TLD} vs D{sub w}: For the energy of {sup 60}Co, {sup 137}Cs, X rays of 250 and 50 kVp. Fitting them with the least square method weighed by means of a polynomial of second grade that corrects the supra linearity of the response. iii. Each one of the curves was validated with a test by lack of fitting and for the Anderson Darling normality test, using the software MINITAB in both cases. iv. The sensibility factor (F{sub s}) for each energy corresponds to the slope of the CC, v. The F{sub s} for the two {sup 192}Ir sources used are interpolated: one for a Micro Selectron source and the other one a Vari Source source. Finally, a couple of

  8. Comparison of absorbed dose in the cervix carcinoma therapy by brachytherapy of high dose rate using the conventional planning and Monte Carlo simulation; Comparacao da dose absorvida no tratamento do cancer ginecologico por braquiterapia de alta taxa de dose utilizando o planejamento convencional do tratamento e simulacao de Monte Carlo

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Aneli Oliveira da

    2010-07-01

    This study aims to compare the doses received for patients submitted to brachytherapy High Dose Rate (HDR) brachytherapy, a method of treatment of the cervix carcinoma, performed in the planning system PLATO BPS with the doses obtained by Monte Carlo simulation using the radiation transport code MCNP 5 and one female anthropomorphic phantom based on voxel, the FAX. The implementation of HDR brachytherapy treatment for the cervix carcinoma consists of the insertion of an intrauterine probe and an intravaginal probe (ring or ovoid) and then two radiographs are obtained, anteroposterior (AP) and lateral (LAT) to confirm the position of the applicators in the patient and to allow the treatment planning and the determination of the absorbed dose at points of interest: rectum, bladder, sigmoid and point A, which corresponds anatomically to the crossings of the uterine arteries with ureters The absorbed doses obtained with the code MCNP 5, with the exception of the absorbed dose in the rectum and sigmoid for the simulation considering a point source of {sup 192}Ir, are lower than the absorbed doses from PLATO BPS calculations because the MCNP 5 considers the chemical compositions and densities of FAX body, not considering the medium as water. When considering the Monte Carlo simulation for a source with dimensions equal to that used in the brachytherapy irradiator used in this study, the values of calculated absorbed dose to the bladder, to the rectum, to the right point A and to the left point A were respectively lower than those determined by the treatment planning system in 33.29, 5.01, 22.93 and 19.04%. These values are almost all larger than the maximum acceptable deviation between patient planned and administered doses (5 %). With regard to the rectum and bladder, which are organs that must be protected, the present results are in favor of the radiological protection of patients. The point A, that is on the isodose of 100%, used to tumor treatment, the results

  9. Dosimetry in intravascular brachytherapy; Calculos dosimetricos em braquiterapia intravascular

    Energy Technology Data Exchange (ETDEWEB)

    Campos, Laelia Pumilla Botelho

    2000-03-01

    Among the cardiovascular diseases responsible for deaths in the adult population in almost all countries of the world, the most common is acute myocardial infarction, which generally occurs because of the occlusion of one or more coronary arteries. Several diagnostic techniques and therapies are being tested for the treatment of coronary artery disease. Balloon angioplasty has been a popular treatment which is less invasive than traditional surgeries involving revascularization of the myocardium, thus promising a better quality of life for patients. Unfortunately, the rate of restenosis (re-closing of the vessel) after balloon angioplasty is high (approximately 30-50% within the first year after treatment).Recently, the idea of delivering high radiation doses to coronary arteries to avoid or delay restenosis has been suggested. Known as intravascular brachytherapy, the technique has been used with several radiation sources, and researchers have obtained success in decreasing the rate of restenosis in some patient populations. In order to study the radiation dosimetry in the patient and radiological protection for the attending staff for this therapy, radiation dose distributions for monoenergetic electrons and photons (at nine discrete energies) were calculated for blood vessels of diameter 0.15, o,30 and 0.45 cm with balloon and wire sources using the radiation transport code MCNP4B. Specific calculations were carried out for several candidate radionuclides as well. Two s tent sources (metallic prosthesis that put inside of patient's artery through angioplasty) employing {sup 32} P are also simulated. Advantages and disadvantages of the various radionuclides and source geometries are discussed. The dosimetry developed here will aid in the realization of the benefits obtained in patients for this promising new technology. (author)

  10. Dosimetric calculus in intravascular brachytherapy; Calculos dosimetricos em braquiterapia intravascular

    Energy Technology Data Exchange (ETDEWEB)

    Campos, Laelia Pumilla Botelho; Stabin, Michael Gregory [Pernambuco Univ., Recife, PE (Brazil). Dept. de Energia Nuclear

    2000-07-01

    Among the cardiovascular diseases, the most common is acute myocardial infarction, which occurs because of the occlusion of one or more coronary arteries. Balloon angioplasty has been a popular treatment which is less invasive than surgeries involving revascularization of the myocardium, thus promising a better quality of life for patients. Unfortunately, the rate of restenosis (re-closing of the vessel) after balloon angioplasty is high (approximately 30-50% within the first year after treatment). Known as Intravascular Brachytherapy, the technique has been used with several radiation sources, and researchers have obtained success in decreasing the rate of restenosis. In order to study the radiation dosimetry in the patient and radiological protection for this therapy, radiation dose distributions for monoenergetic electrons and photons (at nine discrete energies) were calculated for blood vessels of diameter 0.15, 0.30 and 0.45 cm with balloon and wire sources using the radiation transport code MCNP4B. Specific calculations were carried out for several radionuclides. Two stent sources employing {sup 32}P are also simulated. Advantages and disadvantages of the radionuclides and source geometries are discussed and the dosimetry developed here will aid in the realization of the benefits obtained in patients. (author)

  11. Endoluminal isoproterenol reduces renal pelvic pressure during semirigid ureterorenoscopy

    DEFF Research Database (Denmark)

    Jakobsen, Jørn S; Jung, Helene U; Gramsbergen, Jan B

    2009-01-01

    catheter was placed in the renal pelvis for pressure measurements, and a semirigid ureteroscope (7.8 F) was inserted retrogradely in the renal pelvis, through which the pelvis was perfused. The blood pressure and heart rate were recorded. The increase in renal pelvic pressure was examined with increasing....... The pressure-flow relation was linear; the maximum relaxation (27%) was obtained at 4 mL/min, from 52 to 38 mmHg during saline alone and ISO 0.1 microg/mL perfusion, respectively. The mean blood pressure did not change significantly (P = 0.330). The mean (sd) heart rate in the saline and ISO group were 109 (4...... ureterorenoscopy in this porcine model. ISO might be a potential additive to the irrigation fluid during upper urinary tract endoscopic procedures, minimizing pressure increases due to irrigation and manipulation....

  12. Intraoperative HDR Brachytherapy: Present and Future

    NARCIS (Netherlands)

    I.-K.K. Kolkman-Deurloo (Inger-Karina)

    2007-01-01

    textabstractRadiotherapy is one of the most effective modalities in cancer treatment, and can be applied either by external beam radiotherapy or by brachytherapy. Brachytherapy is a treatment modality in which tumors are irradiated by positioning radioactive sources very close to or in the tumor

  13. Breast conserving treatment of locally advanced carcinoma T2 and T3 after neoadjuvant chemotherapy followed by quadrantectomy and high dose-rate brachytherapy, as a boost, complementary teletherapy and adjuvant chemotherapy; Tratamento conservador dos carcinomas de mama localmente avancados T2 e T3, apos quimioterapia neoadjuvante, com quadrantectomia e braquiterapia de alta taxa de dose como reforco de dose, teleterapia complementar e quimioterapia adjuvante

    Energy Technology Data Exchange (ETDEWEB)

    Fristachi, Carlos Elias [Instituto do Cancer Dr. Arnaldo Vieira de Carvalho (ICAVC), Sao Paulo, SP (Brazil). Servico de Onco-Ginecologia e Mastologia]. E-mail: cefristachi@uol.com.br; Miziara Filho, Miguel Abrao; Soares, Celia Regina; Fogaroli, Ricardo Cesar; Pelosi, Edilson Lopes; Martins, Homero Lavieri Martins [Instituto do Cancer Dr. Arnaldo Vieira de Carvalho (ICAVC), Sao Paulo, SP (Brazil). Servico de Radioterapia; Baracat, Fausto Farah [Hospital do Servidor Publico Estadual de Sao Paulo (HSPE), SP (Brazil). Servico de Ginecologia e Mastologia; Piato, Sebastiao [Irmandade da Santa Casa de Misericordia de Sao Paulo, SP (Brazil). Dept. de Obstetricia e Ginecologia (DOGI)

    2005-07-01

    Objective: to assess the treatment of breast cancer T2 and T3(T > = 4 cm), through neoadjuvant chemotherapy, quadrantectomy and high-dose-rate (HDR) brachytherapy as a boost, complementary radiotherapy and adjuvant chemotherapy, considering its method problems, its esthetics results, the aspect of local control, overall survival, and disease-free survival. Patients and method: this clinical prospective descriptive study was based on the evaluation of 26 patients ranging from 30 to 70 years old, with infiltrating ductal carcinoma, clinical stage IIB and IIIA, responsive to the neoadjuvant chemotherapy. Early and late radiotherapy complications were evaluated according to the criteria established by the RTOG/EORTC (Radiotherapy and Oncology Group /European Organization for Research and Treatment of Cancer) groups. Esthetics evaluation was done in accordance with the criteria set by a plastic surgeon. Local control was evaluated by clinical method, mammography and ultrasonography. Overall survival (OS) and the disease-free survival (DFS) were assessed according to Kaplan-Meier methodology. All the patients were treated at the Dr. Arnaldo Vieira de Carvalho Cancer Institute, from June/1995 to November/2001, and evaluated in March, 2002, with median follow-up of 28.7 months. Results: early complications were observed in 8 patients (30.6%). Two patients were classified as G3 and G4 (RTOG/EORTC). Six patients had late complications and three of them (11.5%) were classified as G3 and G4. One patient (3.8%) had local recurrence, 64 months after having local treatment. Esthetics results were considered good or regular in 16 patients (60.5%) out of 24 patients who were examined. Overall survival and disease-free survival in 24, 36 and 60 months were 100%, 92.3% and 83.1% respectively. Conclusion: early and late radiotherapy complications were considerate high when compared to literature, but esthetic results were considered acceptable. RL, OS and DFS were comparable to other

  14. The natural seismic hazard and induced seismicity of the european HDR (hot dry rock) geothermal energy project at Soultz-sous-Forets (Bas-Rhin, France); Alea sismique naturel et sismicite induite du projet geothermique europeen RCS (roche chaude seche) de Soultz-sous-Forets (Bas-Rhin, France)

    Energy Technology Data Exchange (ETDEWEB)

    Helm, J.A.

    1996-06-07

    Development of the Soultz-sous-Forets HDR (Hot Dry Rock) geothermal energy project will involve important fluid injections which will induce micro-seismic events. This thesis discusses the natural seismicity of the region and induced seismicity associated with fluid injections. A catalogue of all historical and instrument seismicity of the Soultz-sous-Forets (SSF) region has been compiled. This seismicity does not correspond to movements along the major tectonic features of the region. The area around SSF has been identified as being one where high heat flow corresponds to low seismicity. The largest well documented seismic event in the region which took place in 1952 had an epicentral intensity of VI. All important data pertaining to the series of seismic events which took place in the region from August to October 1952 have been collected and are presented. This work details the installation and operation of a permanent 3 station network of accelerometers and seismometers around the HDR site. Also the installation and operation of a mobile network of vertical seismometers during fluid injections. 167 micro-seismic events were recorded on the surface network, with magnitudes from -0.5 to 1.9. The preferential alignment of the micro-seismic cloud is N160 deg. Individual focal mechanisms of the larger seismic events correspond to an extensional tectonic regime. Stress inversion of P wave polarities indicates that the maximum stress is vertical and the intermediate and minimum stress axes horizontal. The largest of the horizontal stresses is orientated N124 deg and the smallest N34 deg. Induced seismic movement is taking place on pre-existing fractures controlled by the in situ stress seismic movement is taking place on pre-existing tectonic fractures controlled by the in situ stress field, and the largest of the induced events had a magnitude 1.9. This level of seismicity does not pose any environmental hazard to the region around Soultz-sous-Forets. (author) 151

  15. Radiation Protection in Brachytherapy. Report of the SEFM Task Group on Brachytherapy; Proteccion radiologica en Braquiterapia. Informe del grupo de trabajo de Braquiterapia de la SEFM

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Calatayud, J.; Corredoira Silva, E.; Crispin Contreras, V.; Eudaldo Puell, T.; Frutos Baraja, J. de; Pino Sorroche, F.; Pujades Claumarchirant, M. C.; Richart Sancho, J.

    2015-07-01

    This document presents the report of the Brachytherapy Task Group of the Spanish Society of Medical Physics. It is dedicated to the radiation protection aspects involved in brachytherapy. The aim of this work is to include the more relevant aspects related to radiation protection issues that appear in clinical practice, and for the current equipment in Spain. Basically this report focuses on the typical contents associated with high dose rate brachytherapy with {sup 1}92Ir and {sup 6}0Co sources, and permanent seed implants with {sup 1}25I, {sup 1}03Pd and {sup 1}31Cs, which are the most current and widespread modalities. Ophthalmic brachytherapy (COMS with {sup 1}25I, {sup 1}06Ru, {sup 9}0Sr) is also included due to its availability in a significant number of spanish hospitals. The purpose of this report is to assist to the medical physicist community in establishing a radiation protection program for brachytherapy procedures, trying to solve some ambiguities in the application of legal requirements and recommendations in clinical practice. (Author)

  16. Use of Monte Carlo Methods in brachytherapy; Uso del metodo de Monte Carlo en braquiterapia

    Energy Technology Data Exchange (ETDEWEB)

    Granero Cabanero, D.

    2015-07-01

    The Monte Carlo method has become a fundamental tool for brachytherapy dosimetry mainly because no difficulties associated with experimental dosimetry. In brachytherapy the main handicap of experimental dosimetry is the high dose gradient near the present sources making small uncertainties in the positioning of the detectors lead to large uncertainties in the dose. This presentation will review mainly the procedure for calculating dose distributions around a fountain using the Monte Carlo method showing the difficulties inherent in these calculations. In addition we will briefly review other applications of the method of Monte Carlo in brachytherapy dosimetry, as its use in advanced calculation algorithms, calculating barriers or obtaining dose applicators around. (Author)

  17. Model of distribution of dose for intravascular brachytherapy; Modelo de distribucion de dosis para braquiterapia intravascular

    Energy Technology Data Exchange (ETDEWEB)

    Pirchio, Rosana; Signoretta, Catalina [Comision Nacional de Energia Atomica (CNEA), Buenos Aires (Argentina). Dosimetria de Radioaciones Ionizantes; Martin, Gabriela; Rivera, Elena; Bergoc, Rosa [Univeridad de Buenos Aires (Argentina). Facultad de Farmacia y Bioquimica. Lab. de Radioisotopos; Guzman, Luis [Instituto Cardiovascular de Buenos Aires (Argentina)

    2001-07-01

    In this work we present the radiation dose distributions for a theoretical model with Monte Carlo simulation, which was based on an experimental model developed for the study of the prevention of restenosis post-angioplasty employing intravascular brachytherapy. In the experimental model, the atherosclerotic plaques were induced in femoral arteries of male New Zealand rabbits through surgical intervention and later administration of cholesterol enriched diet. For the intravascular irradiation we employed a {sup 32} P source contained within the balloon used for the angioplasty. The radiation dose distributions were calculated using the Monte Carlo code MCNP4B according to a segment of a simulated artery. We studied the radiation dose distribution in the axial and radial directions for different thickness of the atherosclerotic plaques. The results will be correlated with the biologic effects observed by means of histological analysis of the irradiated arteries. (author)

  18. Braquiterapia electrónica en el carcinoma basocelular superficial y nodular

    OpenAIRE

    Ballester Sánchez, Rosa

    2017-01-01

    El carcinoma basocelular es el cáncer cutáneo más frecuente. Presenta un crecimiento local con poca capacidad de diseminación a distancia, lo que supone una importante morbilidad. Su elevada incidencia conlleva una importante demanda asistencial que genera elevados costes sanitarios. El manejo terapéutico de este tipo de tumor varía en función de las características del paciente (edad, comorbilidades, tratamientos y preferencias) y de la lesión (subtipo, tamaño y localización). Su manejo tera...

  19. Las diferentes modalidades de la radioterapia: externa, braquiterapia e intraoperatoria. Indicaciones

    Directory of Open Access Journals (Sweden)

    Manuel Algara López

    Full Text Available Conclusiones: Se puede afirmar que la radioterapia contribuye a aumentar la supervivencia de las pacientes con cáncer de mama; las mejoras tecnológicas experimentadas en los últimos años han contribuido de forma importante a disminuir la toxicidad; estas mejoras permiten concentrar la radioterapia en menos sesiones, incluso en una única de forma intraoperatoria en un grupo muy seleccionado de pacientes; y que debemos seguir investigado para conocer en que pacientes podemos disminuir nuestros tratamientos, especialmente a nivel ganglionar.

  20. Brachytherapy in childhood rhabdomyosarcoma treatment; Braquiterapia no tratamento do rabdomiossarcoma da infancia

    Energy Technology Data Exchange (ETDEWEB)

    Novaes, Paulo Eduardo Ribeiro dos Santos

    1995-07-01

    A retrospective study of 21 children with rhabdomyosarcoma treated by brachytherapy to the primary site of the tumor at the Radiotherapy Department of the A.C.Camargo Hospital between january/1980 to june/1993 was undertaken. The main objectives were to comprove the utility of brachytherapy in childhood rhabdomyosarcoma, to evaluate the local control and survival, in association with chemotherapy, to analyze the late effects of the treatment and to determinate the preferential technique to each clinical situation. All patients received brachytherapy to the tumor site. The radioactive isotopes employed were Gold{sup 198}, Cesium{sup 137} and Iridium{sup 192}. The brachytherapy techniques depended on the tumor site, period of treatment, availability of the radioactive material and stage of the disease. Patients treated exclusively by brachytherapy received 40 Gy to 60 Gy. When brachytherapy was associated with external radiotherapy the dose ranged from 20 Gy to 40 Gy. Local control was achieved in 18 of 20 patients (90%). The global survival and local control survival rates were 61.9% (13/21 patients) and 72,2% (13/18 patients) respectively. (author)

  1. Quality program for gynecological brachytherapy; Programa de qualidade em braquiterapia ginecologica

    Energy Technology Data Exchange (ETDEWEB)

    Peregrino, Antonio Augusto F.; Almeida, Carlos Eduardo Veloso de [Universidade do Estado, Rio de Janeiro, RJ (Brazil). Dept. de Biofisica e Biometria. Lab. de Ciencias Radiologicas

    1996-12-31

    The implementation of a quality program for a gynecological brachytherapy service is proposed. A remote afterloading technique using low dose rate is considered to establish operational procedures, assuring the prescription of the treatment and the safety of the patients and workers. A periodical personnel training program is suggested as well as the implementation of a treatment record for the patients aiming a interchange in future researches in gynecological cancer treatment among several brachytherapy centres in Brazil 2 refs., 2 figs.

  2. Allogeneic stem cell transplantation after reduced intensity conditioning in patients with relapsed or refractory Hodgkin's lymphoma. Results of the HDR-ALLO study - a prospective clinical trial by the Grupo Español de Linfomas/Trasplante de Médula Osea (GEL/TAMO) and the Lymphoma Working Party of the European Group for Blood and Marrow Transplantation.

    Science.gov (United States)

    Sureda, Anna; Canals, Carme; Arranz, Reyes; Caballero, Dolores; Ribera, Josep Maria; Brune, Mats; Passweg, Jacob; Martino, Rodrigo; Valcárcel, David; Besalduch, Joan; Duarte, Rafael; León, Angel; Pascual, Maria Jesus; García-Noblejas, Ana; López Corral, Lucia; Xicoy, Bianca; Sierra, Jordi; Schmitz, Norbert

    2012-02-01

    Although Hodgkin's lymphoma is a highly curable disease with modern chemotherapy protocols, some patients are primary refractory or relapse after first-line chemotherapy or even after high-dose therapy and autologous stem cell transplantation. We investigated the potential role of allogeneic stem cell transplantation in this setting. In this phase II study 92 patients with relapsed Hodgkin's lymphoma and an HLA-identical sibling, a matched unrelated donor or a one antigen mismatched, unrelated donor were treated with salvage chemotherapy followed by reduced intensity allogeneic transplantation. Fourteen patients showed refractory disease and died from progressive lymphoma with a median overall survival after trial entry of 10 months (range, 6-17). Seventy-eight patients proceeded to allograft (unrelated donors, n=23). Fifty were allografted in complete or partial remission and 28 in stable disease. Fludarabine (150 mg/m(2) iv) and melphalan (140 mg/m(2) iv) were used as the conditioning regimen. Anti-thymocyte globulin was additionally used as graft-versus-host-disease prophylaxis for recipients of grafts from unrelated donors. The non-relapse mortality rate was 8% at 100 days and 15% at 1 year. Relapse was the major cause of failure. The progression-free survival rate was 47% at 1 year and 18% at 4 years from trial entry. For the allografted population, the progression-free survival rate was 48% at 1 year and 24% at 4 years. Chronic graft-versus-host disease was associated with a lower incidence of relapse. Patients allografted in complete remission had a significantly better outcome. The overall survival rate was 71% at 1 year and 43% at 4 years. Allogeneic stem cell transplantation can result in long-term progression-free survival in heavily pre-treated patients with Hodgkin's lymphoma. The reduced intensity conditioning approach significantly reduced non-relapse mortality; the high relapse rate represents the major remaining challenge in this setting. The HDR

  3. Allogeneic stem cell transplantation after reduced intensity conditioning in patients with relapsed or refractory Hodgkin’s lymphoma. Results of the HDR-ALLO study – a prospective clinical trial by the Grupo Español de Linfomas/Trasplante de Médula Osea (GEL/TAMO) and the Lymphoma Working Party of the European Group for Blood and Marrow Transplantation

    Science.gov (United States)

    Sureda, Anna; Canals, Carme; Arranz, Reyes; Caballero, Dolores; Ribera, Josep Maria; Brune, Mats; Passweg, Jacob; Martino, Rodrigo; Valcárcel, David; Besalduch, Joan; Duarte, Rafael; León, Angel; Pascual, Maria Jesus; García-Noblejas, Ana; Corral, Lucia López; Xicoy, Bianca; Sierra, Jordi; Schmitz, Norbert

    2012-01-01

    the major remaining challenge in this setting. The HDR-Allo trial was registered in the European Clinical Trials Database (EUDRACT, https://eudract.ema.europa.eu/) with number 02-0036 PMID:21993674

  4. Minimally invasive autopsy by using postmortem endoluminal and transluminal endoscopy and EUS.

    Science.gov (United States)

    Denzer, Ulrike W; von Renteln, Daniel; Lübke, Andreas; Heinemann, Axel; Rösch, Thomas; Püschel, Klaus; Karbe, Tom

    2013-11-01

    Virtual autopsy by using CT imaging has been introduced as an alternative to conventional autopsy and has resulted in an increase in acceptance of autopsy by relatives. Because direct inspection and tissue acquisition is not possible by imaging alone, various endoscopic techniques can be considered of complementary usefulness. We present the first series of sequential endoscopic techniques including natural orifice transluminal access for minimally invasive autopsy. University hospital, legal medicine department. Twenty deceased subjects. Various flexible endoscopic modalities including EUS, with biopsy or EUS-guided FNA, were attempted. This included transluminal intra-abdominal endoscopic exploration with tissue sampling in a few cases. Completeness of inspection of the luminal and extraluminal cavity as well as tissue acquisition. Complete upper GI endoscopy was performed in 17 of 20 and EUS in 8 of 8 cases. In addition, transgastric intra-abdominal endoscopy was successfully performed in 5 cases. Adequate histology from biopsy and EUS-guided puncture could be obtained in case of short time intervals post mortem. In 1 case, a rupture of the gastric cardia with bleeding was diagnosed as a significant unexpected finding. New minor pathological findings were revealed on EGD (6/17), GI EUS (3/8), and transgastric inspection (4/5). Limited number of cases for all procedures. Minimally invasive autopsy by using multiple endoscopic techniques for imaging and tissue acquisition is feasible. The significant value of this technique, in combination with virtual autopsy compared with classic autopsy, warrants further evaluation. Copyright © 2013 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.

  5. Endoluminal compression clip : full-thickness resection of the mesenteric bowel wall in a porcine model

    NARCIS (Netherlands)

    Kopelman, Yael; Siersema, Peter D.; Nir, Yael; Szold, Amir; Bapaye, Amol; Segol, Ori; Willenz, Ehud P.; Lelcuk, Shlomo; Geller, Alexander; Kopelman, Doron

    2009-01-01

    Background: Performing a full-thickness intestinal wall resection Of a sessile polyp located on the mesenteric side with a compression clip may lead to compression of mesenteric vessels. The application of such a clip may therefore cause a compromised blood supply in the particular bowel segment,

  6. An in vivo endoluminal ultrasonographic study of peristaltic activity in the distal porcine ureter

    NARCIS (Netherlands)

    Roshani, H.; Dabhoiwala, N. F.; Dijkhuis, T.; Kurth, K. H.; Lamers, W. H.

    2000-01-01

    PURPOSE: Experiments were performed to quantify the duration and frequency of ureteric peristaltic activity in the laparotomized and non-laparotomized pig in its virgin and postinstrumented states. MATERIALS AND METHODS: Pigs (n = 10) in a steady state of hydration were studied under halothane

  7. Endoluminal gingival fibroblast transfer reduces the size of rabbit carotid aneurisms via elastin repair.

    Science.gov (United States)

    Durand, Eric; Fournier, Benjamin; Couty, Ludovic; Lemitre, Mathilde; Achouh, Paul; Julia, Pierre; Trinquart, Ludovic; Fabiani, Jean Noel; Seguier, Sylvie; Gogly, Bruno; Coulomb, Bernard; Lafont, Antoine

    2012-08-01

    Matrix metalloproteinase-9 is considered to play a pivotal role in aneurismal formation. We showed that gingival fibroblasts (GF) in vitro reduced matrix metalloproteinase-9 activity via increased secretion of tissue inhibitor of metalloproteinase 1. We aimed to evaluate in vivo the efficacy of GF transplantation to reduce aneurism development in a rabbit model. Seventy rabbit carotid aneurisms were induced by elastase infusion. Four weeks later, GF, dermal fibroblast, or culture medium (DMEM) were infused into established aneurisms. Viable GF were abundantly detected in the transplanted arteries 3 months after seeding. GF engraftment resulted in a significant reduction of carotid aneurisms (decrease of 23.3% [P<0.001] and 17.6% [P=0.01] of vessel diameter in GF-treated arteries, 1 and 3 months after cell therapy, respectively), whereas vessel diameter of control DMEM and dermal fibroblast-treated arteries increased. GF inhibited matrix metalloproteinase-9 activity by tissue inhibitor of metalloproteinase 1 overexpression and matrix metalloproteinase-9/tissue inhibitor of metalloproteinase 1 complex formation, induced elastin repair, and increased elastin density in the media compared with DMEM-treated arteries (38.2 versus 18.0%; P=0.02). Elastin network GF-induced repair was inhibited by tissue inhibitor of metalloproteinase 1 blocking peptide. Our results demonstrate that GF transplantation results in significant aneurism reduction and elastin repair. This strategy may be attractive because GF are accessible and remain viable within the grafted tissue.

  8. Balloon removal after fetoscopic endoluminal tracheal occlusion for congenital diaphragmatic hernia.

    Science.gov (United States)

    Jiménez, Julio A; Eixarch, Elisenda; DeKoninck, Philip; Bennini, João R; Devlieger, Roland; Peralta, Cleisson F; Gratacos, Eduard; Deprest, Jan

    2017-07-01

    Isolated congenital diaphragmatic hernia defect allows viscera to herniate into the chest, competing for space with the developing lungs. At birth, pulmonary hypoplasia leads to respiratory insufficiency and persistent pulmonary hypertension that is lethal in up to 30% of patients. Antenatal measurement of lung size and liver herniation can predict survival after birth. Prenatal intervention aims at stimulating lung development, clinically achieved by percutaneous fetal endoscopic tracheal occlusion under local anesthesia. This in utero treatment requires a second intervention to reestablish the airway, either before birth or at delivery. To describe our experience with in utero endotracheal balloon removal. This is a retrospective analysis of prospectively collected data on consecutive patients with congenital diaphragmatic hernia treated in utero by fetal endoscopic tracheal occlusion from 3 centers. Maternal and pregnancy-associated variables were retrieved. Balloon removal attempts were categorized as elective or emergency and by technique (in utero: ultrasound-guided puncture; fetoscopy; ex utero: on placental circulation or postnatal tracheoscopy). We performed 351 balloon insertions during a 144-month period. In 9 cases removal was attempted outside fetal endoscopic tracheal occlusion centers, 3 of which were deemed impossible and led to neonatal death. We attempted 302 in-house balloon removals in 292 fetuses (217 elective [71.8%], 85 emergency [28.2%]) at 33.4 ± 0.1 weeks (range: 28.9-37.1), with a mean interval to delivery of 16.6 ± 0.8 days (0-85). Primary attempt was by fetoscopy in 196 (67.1%), by ultrasound-guided puncture in 62 (21.2%), by tracheoscopy on placental circulation in 30 (10.3%), and postnatal tracheoscopy in 4 cases (1.4%); a second attempt was required in 10 (3.4%) cases. Each center had different preferences for primary technique selection. In elective removals, we found no differences in the interval to delivery between fetoscopic and ultrasound-guided puncture removals. Difficulties during fetoscopic removal led to the development of a stylet to puncture the balloon, leading to shorter operating time and easier reestablishment of airways. In these fetal treatment centers, the balloon could always be removed successfully. In 90% this was in utero, with the use of fetoscopy preferred over ultrasound-guided puncture. Ex utero removal was a fall-back procedure. In utero removal does not seem to precipitate immediate membrane rupture, labor, or delivery, although the design of the study did not allow for a formal conclusion. For fetoscopic removals, the introduction of a stylet facilitated retrieval. Successful removal may rely on a permanently prepared team with expertise in all possible techniques. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. The endoluminal bypass for occlusive lesions of the superficial femoral artery

    NARCIS (Netherlands)

    Lensvelt, Martha Maria Antonia

    2013-01-01

    Het plaatsen van een stent bij patiënten met perifere vaatziekten leidt tot minder complicaties dan een chirurgische omleiding. Het risico op wondgenezingsstoornissen en oedeem (vochtophoping) is kleiner en de opnameduur in het ziekenhuis aanmerkelijk korter. Dat concludeert Mare Lensvelt in haar

  10. Transit dose calculation in high dose rate brachytherapy (HDR ...

    African Journals Online (AJOL)

    Transit doses around a high dose rate 192Ir brachytherapy source were calculated using Sievert Integral at positions where the moving source was located exactly between two adjacent dwell positions. The correspond-ing transit dose rates were obtained by using energy absorption coefficients. Discrete step sizes of 0.25 ...

  11. Automatic Level Control for Video Cameras towards HDR Techniques

    Directory of Open Access Journals (Sweden)

    de With PeterHN

    2010-01-01

    Full Text Available We give a comprehensive overview of the complete exposure processing chain for video cameras. For each step of the automatic exposure algorithm we discuss some classical solutions and propose their improvements or give new alternatives. We start by explaining exposure metering methods, describing types of signals that are used as the scene content descriptors as well as means to utilize these descriptors. We also discuss different exposure control types used for the control of lens, integration time of the sensor, and gain control, such as a PID control, precalculated control based on the camera response function, and propose a new recursive control type that matches the underlying image formation model. Then, a description of commonly used serial control strategy for lens, sensor exposure time, and gain is presented, followed by a proposal of a new parallel control solution that integrates well with tone mapping and enhancement part of the image pipeline. Parallel control strategy enables faster and smoother control and facilitates optimally filling the dynamic range of the sensor to improve the SNR and an image contrast, while avoiding signal clipping. This is archived by the proposed special control modes used for better display and correct exposure of both low-dynamic range and high-dynamic range images. To overcome the inherited problems of limited dynamic range of capturing devices we discuss a paradigm of multiple exposure techniques. Using these techniques we can enable a correct rendering of difficult class of high-dynamic range input scenes. However, multiple exposure techniques bring several challenges, especially in the presence of motion and artificial light sources such as fluorescent lights. In particular, false colors and light-flickering problems are described. After briefly discussing some known possible solutions for the motion problem, we focus on solving the fluorescence-light problem. Thereby, we propose an algorithm for the detection of fluorescent lights from the image itself and define a set of remedial actions, to minimize false color and light-flickering problems.

  12. Dosimetric equivalence of nonstandard HDR brachytherapy catheter patterns

    Energy Technology Data Exchange (ETDEWEB)

    Cunha, J. A. M.; Hsu, I-C.; Pouliot, J. [University of California, San Francisco, California 94115 (United States)

    2009-01-15

    Purpose: To determine whether alternative high dose rate prostate brachytherapy catheter patterns can result in similar or improved dose distributions while providing better access and reducing trauma. Materials and Methods: Standard prostate cancer high dose rate brachytherapy uses a regular grid of parallel needle positions to guide the catheter insertion. This geometry does not easily allow the physician to avoid piercing the critical structures near the penile bulb nor does it provide position flexibility in the case of pubic arch interference. This study used CT datasets with 3 mm slice spacing from ten previously treated patients and digitized new catheters following three hypothetical catheter patterns: conical, bi-conical, and fireworks. The conical patterns were used to accommodate a robotic delivery using a single entry point. The bi-conical and fireworks patterns were specifically designed to avoid the critical structures near the penile bulb. For each catheter distribution, a plan was optimized with the inverse planning algorithm, IPSA, and compared with the plan used for treatment. Irrelevant of catheter geometry, a plan must fulfill the RTOG-0321 dose criteria for target dose coverage (V{sub 100}{sup Prostate}>90%) and organ-at-risk dose sparing (V{sub 75}{sup Bladder}<1 cc, V{sub 75}{sup Rectum}<1 cc, V{sub 125}{sup Urethra}<<1 cc). Results: The three nonstandard catheter patterns used 16 nonparallel, straight divergent catheters, with entry points in the perineum. Thirty plans from ten patients with prostate sizes ranging from 26 to 89 cc were optimized. All nonstandard patterns fulfilled the RTOG criteria when the clinical plan did. In some cases, the dose distribution was improved by better sparing the organs-at-risk. Conclusion: Alternative catheter patterns can provide the physician with additional ways to treat patients previously considered unsuited for brachytherapy treatment (pubic arch interference) and facilitate robotic guidance of catheter insertion. In addition, alternative catheter patterns may decrease toxicity by avoidance of the critical structures near the penile bulb while still fulfilling the RTOG criteria.

  13. Spatial imaging in color and HDR: prometheus unchained

    Science.gov (United States)

    McCann, John J.

    2013-03-01

    The Human Vision and Electronic Imaging Conferences (HVEI) at the IS and T/SPIE Electronic Imaging meetings have brought together research in the fundamentals of both vision and digital technology. This conference has incorporated many color disciplines that have contributed to the theory and practice of today's imaging: color constancy, models of vision, digital output, high-dynamic-range imaging, and the understanding of perceptual mechanisms. Before digital imaging, silver halide color was a pixel-based mechanism. Color films are closely tied to colorimetry, the science of matching pixels in a black surround. The quanta catch of the sensitized silver salts determines the amount of colored dyes in the final print. The rapid expansion of digital imaging over the past 25 years has eliminated the limitations of using small local regions in forming images. Spatial interactions can now generate images more like vision. Since the 1950's, neurophysiology has shown that post-receptor neural processing is based on spatial interactions. These results reinforced the findings of 19th century experimental psychology. This paper reviews the role of HVEI in color, emphasizing the interaction of research on vision and the new algorithms and processes made possible by electronic imaging.

  14. Obtention of brachytherapy seeds by sealing process using polymer; Obtencao de sementes de braquiterapia pelo processo de selagem com polimero

    Energy Technology Data Exchange (ETDEWEB)

    Lana, Diogo Alberto P.D.; Ferraz, Wilmar B.; Santos, Ana Maria M., E-mail: amms@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Carvalho, Luiz Claudio F.M. Garcia [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil)

    2012-08-15

    Brachytherapy is an advanced cancer treatment where radioactive seeds or sources are placed near or directly into the tumor thus reducing the radiation exposure in the surrounding healthy tissues. Several kinds of seeds have been developed in order to obtain a better dose distribution around them and with a lower cost manufacturing. These seeds consist of an encapsulation (titanium or stainless steel tube), a radionuclide carrier, and X-ray marker. The usual sealing process of the seeds is done with laser welding, but this process can promote radionuclide volatilization. In this paper, we present a new sealing process using epoxy resin and characterizations of two epoxy resins. These resins were characterized by Fourier transform infrared spectroscopic (FTIR), ultraviolet-visible spectroscopy (UV-vis) and differential scanning calorimetry (DSC). Interactions of the resins and of the sealed seeds in a simulated body fluid (SBF) were evaluated by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and by a counting gamma-rays. (author)

  15. Manual method for dose calculation in gynecologic brachytherapy; Metodo manual para o calculo de doses em braquiterapia ginecologica

    Energy Technology Data Exchange (ETDEWEB)

    Vianello, Elizabeth A.; Almeida, Carlos E. de [Instituto Nacional do Cancer, Rio de Janeiro, RJ (Brazil); Biaggio, Maria F. de [Universidade do Estado, Rio de Janeiro, RJ (Brazil)

    1998-09-01

    This paper describes a manual method for dose calculation in brachytherapy of gynecological tumors, which allows the calculation of the doses at any plane or point of clinical interest. This method uses basic principles of vectorial algebra and the simulating orthogonal films taken from the patient with the applicators and dummy sources in place. The results obtained with method were compared with the values calculated with the values calculated with the treatment planning system model Theraplan and the agreement was better than 5% in most cases. The critical points associated with the final accuracy of the proposed method is related to the quality of the image and the appropriate selection of the magnification factors. This method is strongly recommended to the radiation oncology centers where are no treatment planning systems available and the dose calculations are manually done. (author) 10 refs., 5 figs.

  16. Importance of the elemental composition in brachytherapy with neutrons; Importancia de la composicion elemental en braquiterapia con neutrones

    Energy Technology Data Exchange (ETDEWEB)

    Paredes G, L.; Balcazar G, M. [ININ, A.P. 18-1027, 11801 Mexico D.F. (Mexico); Azorin N, J. [UAM-I, 09340 Mexico D.F. (Mexico); Francois L, J.L. [ICN-UNAM, 04510 Mexico D.F. (Mexico)

    2004-07-01

    An analysis is presented of as the small differences that exist in the elementary composition of the wicked tumors, healthy fabrics and some material substitutes of fabric employees in dosimetry, they generate variations in the value of the kerma coefficient and consequently in the absorbed dose of neutrons in the interval 11 eV to 29 MeV. These differences make that the coefficient of kerma of neutrons average for the considered wicked tumors, be between 6% and 7% smaller that the coefficient of kerma of neutrons average for soft fabric, in the interval of interest in therapy with quick neutrons. These results have a special importance during the process of planning of brachytherapy treatments with sources of {sup 252} Cf, to optimize and to individualize the treatments to the patients. (Author)

  17. Divergence of Cs-137 sources fluence used in brachytherapy; Divergencia da fluencia de fontes de Cs-137 usadas em braquiterapia

    Energy Technology Data Exchange (ETDEWEB)

    Vianello, E.A.; Almeida, C.E. de [Laboratorio de Ciencias Radiologicas- LCR-DBB (UERJ). R. Sao Francisco Xavier, 524- Pav. HLC, sala 136 terreo- CEP 20.550- 013. Rio de Janeiro (Brazil)

    1998-12-31

    In this work the experimental determination of correction factor for fluence divergence (kln) of linear Cs-137 sources CDCS J4, with Farmer ionization chamber model 2571 in a central and perpendicular plan to source axis, for distances range from 1 to 7 cm., has been presented. The experimental results were compared to calculating by Kondo and Randolph (1960) isotropic theory and Bielajew (1990) anisotropic theory. (Author)

  18. Prótesis endoluminal autoexpandible en una oclusión aguda por tumor del colon izquierdo Self-expanding endoluminal prosthesis in an acute occlusion due to left colon tumor

    Directory of Open Access Journals (Sweden)

    Manuel Cepero Valdés

    2011-06-01

    Full Text Available Se describe la utilización endoscópica de prótesis autoexpandibles en dos pacientes con oclusión mecánica aguda del colon izquierdo, tratados en el servicio de urgencias, lo que permitió mejorar el estado hidroelectrolítico y sintomático de los pacientes, así como la preparación del colon. Esto último evitó una cirugía de urgencia y colostomía descompresiva, y la intervención quirúrgica se programó para los 5 posteriores. No hubo complicaciones posoperatorias. El resultado anatomopatológico confirmó sendos adenocarcinomas de colon en anillo de sellos, en un paciente en el colon descendente y en el otro en el colon sigmoides.Endoscopic use of self-expanding prostheses is described in two patients with acute mechanical occlusion of left colon, treated in the emergence service of our center allowing us to improve the hydroelectric symptomatic status of patients, as well as the colon preparation. This latter avoided an emergence surgery and decompression colostomy; surgery was programmed for the subsequent five ones. Anatomical-pathological results confirmed the presence of large seal-ring colon's adenocarcinomas in the descendent colon in a patient, and in the sigmoid colon in another one.

  19. Endoluminal brachytherapy in the treatment of oesophageal cancer: technique description, case report and review of the literature

    Directory of Open Access Journals (Sweden)

    Luisa Castilla

    2015-07-01

    Full Text Available Endoesophageal brachytherapy is a useful technique for the palliative treatment of dysphagia in advanced oesophageal cancer. This technique offers good results on dysphagia control and quality of life. We report the case of a patient treated with this technique presenting complete response to the dysphagia. We describe endoesophageal brachyterapy technique and we comment on the literature.

  20. Intravenous, contrast-enhanced MR colonography using air as endoluminal contrast agent: Impact on colorectal polyp detection.

    LENUS (Irish Health Repository)

    Keeling, Aoife N

    2012-02-01

    PURPOSE: To compare diagnostic accuracy and patient tolerance of MR colonography with intravenous contrast and luminal air (MRC) to conventional colonoscopy (CC). MATERIALS AND METHODS: IRB approval and written informed consent were obtained. Forty-six patients, both screening and symptomatic, underwent MRC followed by CC. The MRC technique employed 3D T1W spoiled gradient echo sequences performed after the administration of gadopenetate dimeglumine, with parallel imaging. The diagnostic accuracy and tolerance of patients for MRC was compared to CC. RESULTS: Twenty-four polyps were detected in eighteen patients with CC (5 polyps >\\/=10mm, 4 polyps 6-9mm, 15 polyps <\\/=5mm). MRC was 66.7% (12\\/18) sensitive and 96.4% (27\\/28) specific for polyp detection on a per-patient basis. When analyzed by polyp size, sensitivity and specificity of MRC was 100% (5\\/5) and 100% (19\\/19), respectively, for lesions greater than 10mm, 100% (4\\/4) and 100% (20\\/20) for lesions 6-9mm, and sensitivity of 20% (3\\/15) lesions less than 5mm. The sensitivity and specificity of MRC for detecting significant lesions (>6mm) was 100% (9\\/9) and 100% (15\\/15), respectively. Regarding tolerance of the exams, there were no significant differences between MRC and CC. Thirty-five percent (n=16) of patients preferred MRC as a future screening test compared to 33% (n=15) for CC. CONCLUSION: MRC using air as an intraluminal contrast agent is a feasible and well-tolerated technique for detecting colonic polyps >\\/=6mm in size. Further studies are warranted.

  1. Remission of heart failure through endoluminal repair of femoral arteriovenous fistula with the use of a covered stent

    Directory of Open Access Journals (Sweden)

    Portela Antenor

    2001-01-01

    Full Text Available We report the case of a 21-year-old male with high-output heart failure due to a femoral arteriovenous fistula caused by a firearm wound. A new balloon expandable stent covered with polytetrafluorethylene was implanted in the artery to occlude the arteriovenous fistula. The fistula was immediately occluded and the artery remained patent. On the following day, the patient felt much better, with no symptoms of heart failure. Additional follow-up is required to assure the usefulness of this less invasive procedure in the treatment of arteriovenous fistulas.

  2. Tratamiento endoluminal de disección aguda complicada en aorta descendente: Comunicación de un caso

    OpenAIRE

    Fava P,Mario; Espíndola,Manuel; Bertoni,Hernán; Loyola Z,M Soledad; Meneses Q,Luis; Maureira,Mauricio

    2006-01-01

    Acute dissection of the aorta, although not common, has early and highly lethal complications. The type A dissection is treated with surgery. Patients with type B dissections are treated with surgery if they have complications like rupture, growth or visceral ischemia. Surgery, however, has complications such as spinal cord ischemia. Endovascular grafts have less mortality and complications. We report a 59 years old male patient with a type B dissection complicated with rupture. He was treate...

  3. Intravenous, contrast-enhanced MR colonography using air as endoluminal contrast agent: Impact on colorectal polyp detection.

    LENUS (Irish Health Repository)

    Keeling, Aoife N

    2010-12-03

    PURPOSE: To compare diagnostic accuracy and patient tolerance of MR colonography with intravenous contrast and luminal air (MRC) to conventional colonoscopy (CC). MATERIALS AND METHODS: IRB approval and written informed consent were obtained. Forty-six patients, both screening and symptomatic, underwent MRC followed by CC. The MRC technique employed 3D T1W spoiled gradient echo sequences performed after the administration of gadopenetate dimeglumine, with parallel imaging. The diagnostic accuracy and tolerance of patients for MRC was compared to CC. RESULTS: Twenty-four polyps were detected in eighteen patients with CC (5 polyps ≥10mm, 4 polyps 6-9mm, 15 polyps ≤5mm). MRC was 66.7% (12\\/18) sensitive and 96.4% (27\\/28) specific for polyp detection on a per-patient basis. When analyzed by polyp size, sensitivity and specificity of MRC was 100% (5\\/5) and 100% (19\\/19), respectively, for lesions greater than 10mm, 100% (4\\/4) and 100% (20\\/20) for lesions 6-9mm, and sensitivity of 20% (3\\/15) lesions less than 5mm. The sensitivity and specificity of MRC for detecting significant lesions (>6mm) was 100% (9\\/9) and 100% (15\\/15), respectively. Regarding tolerance of the exams, there were no significant differences between MRC and CC. Thirty-five percent (n=16) of patients preferred MRC as a future screening test compared to 33% (n=15) for CC. CONCLUSION: MRC using air as an intraluminal contrast agent is a feasible and well-tolerated technique for detecting colonic polyps ≥6mm in size. Further studies are warranted.

  4. The role of superficial femoral artery endoluminal bypass in long de novo lesions and in-stent restenosis.

    NARCIS (Netherlands)

    Doomernik, D.E.; Golchehr, B.; Lensvelt, M.M.A.; Reijnen, M.M.P.J.

    2012-01-01

    AIM: Results of endovascular treatment for long de novo lesions of the superficial femoral artery (SFA) are limited by in-stent restenosis (ISR). Polytetrafluoroethylene (PTFE) covered stents are developed to reduce the incidence of ISR. This study was conducted to summarize available data on the

  5. What Bariatric Surgery Can Teach Us About Endoluminal Treatment of Obesity and Metabolic Disorders.

    Science.gov (United States)

    Kaplan, Lee M

    2017-04-01

    Bariatric surgical procedures, including gastric bypass, vertical sleeve gastrectomy, and biliopancreatic diversion, are the most effective and durable treatments for obesity. In addition, These operations induce metabolic changes that provide weight-independent improvement in type 2 diabetes, fatty liver disease and other metabolic disorders. Initially thought to work by mechanical restriction of food intake or malabsorption of ingested nutrients, these procedures are now known to work through complex changes in neuroendocrine and immune signals emanating from the gut, including peptide hormones, bile acids, vagal nerve activity, and metabolites generated by the gut microbiota, all collaborating to reregulate appetite, food preference, and energy expenditure. Development of less invasive means of achieving these benefits would allow much greater dissemination of effective, gastrointestinal (GI)-targeted therapies for obesity and metabolic disorders. To reproduce the benefits of bariatric surgery, however, these endoscopic procedures and devices will need to mimic the physiological rather than the mechanical effects of these operations. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Disfunção sexual em pacientes com câncer do colo uterino avançado submetidas à radioterapia exclusiva Sexual dysfunction in patients with advanced cervical cancer submitted to exclusive radiotherapy

    Directory of Open Access Journals (Sweden)

    Bebiana Calisto Bernardo

    2007-02-01

    Full Text Available OBJETIVO: identificar disfunções sexuais em pacientes com câncer de colo uterino submetidas à radioterapia exclusiva pela técnica de braquiterapia de alta taxa de dose. MÉTODOS: foi realizado um estudo descritivo do tipo corte transversal no período de janeiro a junho de 2004. O estudo envolveu 71 pacientes selecionadas de acordo o perfil estabelecido e que vinham sendo seguidas no ambulatório de pélvis do Hospital do Câncer de Pernambuco. Os dados foram coletados a partir de um questionário estruturado, complementado por um exame ginecológico visando investigar queixas de disfunção sexual após a radioterapia. Foi utilizado o programa estatístico Epi-Info 6.04 para processamento e análise dos dados. A análise descritiva foi feita pela média, mediana, valores máximo e mínimo. Para análise bivariada foram realizados os testes de homogeneidade marginal e McNemar, considerando um nível de significância de 5%. RESULTADOS: das complicações ginecológicas identificadas, destacam-se fibrose, estenose e atrofia vaginais (98,6, 76,1 e 71,8% dos casos, respectivamente. As disfunções sexuais identificadas foram: frigidez e falta de lubrificação, de excitação e de orgasmo, que ocorreram em 76,1% dos casos, falta de libido em 40,8% e vaginismo em 5,6% dos casos. CONCLUSÕES: as disfunções sexuais são freqüentes em pacientes com câncer do colo uterino avançado tratadas com radioterapia exclusiva utilizando o protocolo de braquiterapia de alta taxa de dose. Atenção específica deve ser dada à anamnese sexual e ao exame ginecológico durante o acompanhamento destas pacientes.PURPOSE: to identify sexual dysfunctions in patients with cancer of the uterine cervix submitted to exclusive radiotherapy, using the high dose rate (HDR brachytherapy technique. METHODS: a descriptive transversal study from January to June of 2004. The study involved 71 selected patients who had been followed in the pelvis outpatient clinic from the

  7. Photometric and Colorimeric Comparison of HDR and Spctrally Resolved Rendering Images

    DEFF Research Database (Denmark)

    Amdemeskel, Mekbib Wubishet; Soreze, Thierry Silvio Claude; Thorseth, Anders

    2017-01-01

    . The spectral irradiances of the light source were measured for two lighting scenarios: low and high correlated colour temperature (CCT) white lighting conditions for the modelling of the light source. Based on these measurements, we have conducted spectrally resolved renderings with a spectral renderer, Ocean...

  8. Long-time water level observations at the HDR-testsite Soultz-sous-Forets

    Energy Technology Data Exchange (ETDEWEB)

    Dornstaedter, J.; Heinemann-Glutsch, B.; Zaske, J. [GTC-Kappelmeyer GmbH, Karlsruhe (Germany)

    1997-12-01

    Pressure or water level measurements have been performed by GTC in different wells at the geothermal testsite Soultz-sous-Forets for six years now. The water lever variations are mainly influenced by earth tides, barometric pressure variations, hydraulic testing and stimulation. The small scale variations are influenced by tidal and barometric forcing functions, the large scale variations by hydraulic testing and stimulation. By analyzing such measurements it is possible to get important information about the hydrualic connections between the boreholes, as well as aquifer parameters. (orig./AKF)

  9. Improved vegetation segmentation with ground shadow removal using an HDR camera

    NARCIS (Netherlands)

    Suh, Hyun K.; Hofstee, Jan W.; Henten, van Eldert J.

    2017-01-01

    A vision-based weed control robot for agricultural field application requires robust vegetation segmentation. The output of vegetation segmentation is the fundamental element in the subsequent process of weed and crop discrimination as well as weed control. There are two challenging issues for

  10. Objective Video Quality Assessment of Direct Recording and Datavideo HDR-40 Recording System

    Directory of Open Access Journals (Sweden)

    Nofia Andreana

    2016-10-01

    Full Text Available Digital Video Recorder (DVR is a digital video recorder with hard drive storage media. When the capacity of the hard disk runs out. It will provide information to users and if there is no response, it will be overwritten automatically and the data will be lost. The main focus of this paper is to enable recording directly connected to a computer editor. The output of both systems (DVR and Direct Recording will be compared with an objective assessment using the Mean Square Error (MSE and Peak Signal to Noise Ratio (PSNR parameter. The results showed that the average value of MSE Direct Recording dB 797.8556108, 137.4346100 DVR MSE dB and the average value of PSNR Direct Recording and DVR PSNR dB 19.5942333 27.0914258 dB. This indicates that the DVR has a much better output quality than Direct Recording.

  11. The drama of illumination: artist's approaches to the creation of HDR in paintings and prints

    Science.gov (United States)

    Parraman, Carinna

    2010-02-01

    For many centuries artists have considered and depicted illumination in art, from the effect of sunlight on objects at different times of the day, of shadows and highlights as cast by the moon, through indirect light as that through an open window or the artificial light of the candle or firelight. The presentation will consider artists who were fascinated by the phenomena of natural and artificial illumination and how they were able to render the natural world as a form of dynamic range through pigment. Artists have been long aware of the psychological aspects of the juxtaposition of colour in exploiting the optical qualities and arranging visual effects in painting and prints. Artists in the 16th century were attempting to develop an extended dynamic range through multi-colour, wood-block printing. Artists working at the height of naturalist realism in the 17th through the 19th century were fascinated by the illusory nature of light on objects. The presentation will also consider the interpretation of dynamic range through the medium of mezzotint, possibly the most subtle of printing methods, which was used by printers to copy paintings, and to create highly original works of art containing a dynamic range of tones.

  12. TU-AB-201-07: Image Guided Endorectal HDR Brachytherapy Using a Compliant Balloon Applicator

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, G; Goodman, K [Memorial Sloan Kettering Cancer Center, New York, NY (United States)

    2015-06-15

    Purpose: High dose rate endorectal brachytherapy is an option to deliver a focal, high-dose radiotherapy to rectal tumors for patients undergoing non-operative management. We investigate a new multichannel, MR compatible applicator with a novel balloon-based design to provide improved treatment geometry. We report on the initial clinical experience using this applicator. Methods: Patients were enrolled on an IRB-approved, dose-escalation protocol evaluating the use of the anorectal (AR-1) applicator (Ancer Medical, Hialeah, FL), a multichannel applicator with two concentric balloons. The inner balloon supports 8 source lumens; the compliant outer balloon expands to separate the normal rectal wall and the source lumens, yet deforms around a firm, exophytic rectal mass, leading to dose escalation to tumor while sparing normal rectum. Under general anesthesia, gold fiducial markers were inserted above and below the tumor, and the AR applicator was placed in the rectum. MRI-based treatment plans were prepared to deliver 15 Gy in 3 weekly fractions to the target volume while sparing healthy rectal tissue, bladder, bowel and anal muscles. Prior to each treatment, CBCT/Fluoroscopy were used to place the applicator in the treatment position and confirm the treatment geometry using rigid registration of the CBCT and planning MRI. After registration of the applicator images, positioning was evaluated based on the match of the gold markers. Results: Highly conformal treatment plans were achieved. MR compatibility of the applicator enabled good tumor visualization. In spite of the non-rigid nature of the applicators and the fact that a new applicator was used at each treatment session, treatment geometry was reproducible to within 2.5 mm. Conclusions: This is the first report on using the AR applicator in patients. Highly conformal plans, confidence in MRI target delineation, in combination with reproducible treatment geometry provide encouraging feedback for continuation with dose escalation in these patients.

  13. Joint deformable liver registration and bias field correction for MR-guided HDR brachytherapy.

    Science.gov (United States)

    Rak, Marko; König, Tim; Tönnies, Klaus D; Walke, Mathias; Ricke, Jens; Wybranski, Christian

    2017-12-01

    In interstitial high-dose rate brachytherapy, liver cancer is treated by internal radiation, requiring percutaneous placement of applicators within or close to the tumor. To maximize utility, the optimal applicator configuration is pre-planned on magnetic resonance images. The pre-planned configuration is then implemented via a magnetic resonance-guided intervention. Mapping the pre-planning information onto interventional data would reduce the radiologist's cognitive load during the intervention and could possibly minimize discrepancies between optimally pre-planned and actually placed applicators. We propose a fast and robust two-step registration framework suitable for interventional settings: first, we utilize a multi-resolution rigid registration to correct for differences in patient positioning (rotation and translation). Second, we employ a novel iterative approach alternating between bias field correction and Markov random field deformable registration in a multi-resolution framework to compensate for non-rigid movements of the liver, the tumors and the organs at risk. In contrast to existing pre-correction methods, our multi-resolution scheme can recover bias field artifacts of different extents at marginal computational costs. We compared our approach to deformable registration via B-splines, demons and the SyN method on 22 registration tasks from eleven patients. Results showed that our approach is more accurate than the contenders for liver as well as for tumor tissues. We yield average liver volume overlaps of 94.0 ± 2.7% and average surface-to-surface distances of 2.02 ± 0.87 mm and 3.55 ± 2.19 mm for liver and tumor tissue, respectively. The reported distances are close to (or even below) the slice spacing (2.5 - 3.0 mm) of our data. Our approach is also the fastest, taking 35.8 ± 12.8 s per task. The presented approach is sufficiently accurate to map information available from brachytherapy pre-planning onto interventional data. It is also reasonably fast, providing a starting point for computer-aidance during intervention.

  14. A comparison of inverse optimization algorithms for HDR/PDR prostate brachytherapy treatment planning.

    Science.gov (United States)

    Dinkla, Anna M; van der Laarse, Rob; Kaljouw, Emmie; Pieters, Bradley R; Koedooder, Kees; van Wieringen, Niek; Bel, Arjan

    2015-01-01

    Graphical optimization (GrO) is a common method for high-dose-rate/pulsed-dose-rate (PDR) prostate brachytherapy treatment planning. New methods performing inverse optimization of the dose distribution have been developed over the past years. The purpose is to compare GrO and two established inverse methods, inverse planning simulated annealing (IPSA) and hybrid inverse treatment planning and optimization (HIPO), and one new method, enhanced geometric optimization-interactive inverse planning (EGO-IIP), in terms of speed and dose-volume histogram (DVH) parameters. For 26 prostate cancer patients treated with a PDR brachytherapy boost, an experienced treatment planner optimized the dose distributions using four different methods: GrO, IPSA, HIPO, and EGO-IIP. Relevant DVH parameters (prostate-V100%, D90%, V150%; urethra-D(0.1cm3) and D(1.0cm3); rectum-D(0.1cm3) and D(2.0cm3); bladder-D(2.0cm3)) were evaluated and their compliance to the constraints. Treatment planning time was also recorded. All inverse methods resulted in shorter planning time (mean, 4-6.7 min), as compared with GrO (mean, 7.6 min). In terms of DVH parameters, none of the inverse methods outperformed the others. However, all inverse methods improved on compliance to the planning constraints as compared with GrO. On average, EGO-IIP and GrO resulted in highest D90%, and the IPSA plans resulted in lowest bladder D2.0cm3 and urethra D(1.0cm3). Inverse planning methods decrease planning time as compared with GrO for PDR/high-dose-rate prostate brachytherapy. DVH parameters are comparable for all methods. Copyright © 2015 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  15. Comparison of IPSA and HIPO inverse planning optimization algorithms for prostate HDR brachytherapy.

    Science.gov (United States)

    Panettieri, Vanessa; Smith, Ryan L; Mason, Natasha J; Millar, Jeremy L

    2014-11-08

    Publications have reported the benefits of using high-dose-rate brachytherapy (HDRB) for the treatment of prostate cancer, since it provides similar biochemical control as other treatments while showing lowest long-term complications to the organs at risk (OAR). With the inclusion of anatomy-based inverse planning opti- mizers, HDRB has the advantage of potentially allowing dose escalation. Among the algorithms used, the Inverse Planning Simulated Annealing (IPSA) optimizer is widely employed since it provides adequate dose coverage, minimizing dose to the OAR, but it is known to generate large dwell times in particular positions of the catheter. As an alternative, the Hybrid Inverse treatment Planning Optimization (HIPO) algorithm was recently implemented in Oncentra Brachytherapy V. 4.3. The aim of this work was to compare, with the aid of radiobiological models, plans obtained with IPSA and HIPO to assess their use in our clinical practice. Thirty patients were calculated with IPSA and HIPO to achieve our department's clinical constraints. To evaluate their performance, dosimetric data were collected: Prostate PTV D90(%), V100(%), V150(%), and V200(%), Urethra D10(%), Rectum D2cc(%), and conformity indices. Additionally tumor control probability (TCP) and normal tissue complication probability (NTCP) were calculated with the BioSuite software. The HIPO optimization was performed firstly with Prostate PTV (HIPOPTV) and then with Urethra as priority 1 (HIPOurethra). Initial optimization constraints were then modified to see the effects on dosimetric parameters, TCPs, and NTCPs. HIPO optimizations could reduce TCPs up to 10%-20% for all PTVs lower than 74 cm3. For the urethra, IPSA and HIPOurethra provided similar NTCPs for the majority of volume sizes, whereas HIPOPTV resulted in large NTCP values. These findings were in agreement with dosimetric values. By increasing the PTV maximum dose constraints for HIPOurethra plans, TCPs were found to be in agreement with IPSA without affecting the urethral NTCPs. 

  16. Dose verification in HDR brachytherapy and IMRT with Fricke gel-layer dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Gambarini, G.; Negri, A.; Bartesaghi, G.; Pirola, L. [Department of Physics, Universita degli Studi di Milano, Italy (Italy); Carrara, M.; Gambini, I.; Tomatis, S.; Fallai, C.; Zonca, G. [Fondazione IRCCS Istituto Nazionale dei Tumori, Milano, Italy (Italy); Stokucova, J. [Faculty Hospital Na Bulovce, Prague, Czech Republic (Czech Republic)

    2009-10-15

    At the Department of Physics of the Universita degli Studi di Milano in collaboration with the Medical Physics Unit and the Radiotherapy Unit of the Fondazione IRCCS Istituto Nazionale dei Tumori di Milano the research of a dosimetric technique based on Fricke gel layers and optical analysis in under study. In fact, Fricke gel layer dosimeters (FGLD) have various advantages such as the tissue-equivalence for photons in the clinical energy interval, the possibility to obtain the spatial information about continuous dose distribution and not only a point dose distribution as it is for example in the case of ionization chambers, TLD or diodes and the possibility to obtain the information about 3D dose distributions. In this work, specific applications of FGLD to absolute dosimetry in radiotherapy have been studied, i.e. in-phantom measurements of complex intensity modulated radiation therapy fields (IMRT) and complex brachytherapy fields. (Author)

  17. Retrospective review of Contura HDR breast cases to improve our standardized procedure

    Energy Technology Data Exchange (ETDEWEB)

    Iftimia, Ileana, E-mail: Ileana.n.iftimia@lahey.org [Lahey Clinic, Radiation Oncology Department, MA (United States); Cirino, Eileen T.; Ladd, Ron; Mower, Herbert W.; McKee, Andrea B. [Lahey Clinic, Radiation Oncology Department, MA (United States)

    2013-07-01

    To retrospectively review our first 20 Contura high dose rate breast cases to improve and refine our standardized procedure and checklists. We prepared in advance checklists for all steps, developed an in-house Excel spreadsheet for second checking the plan, and generated a procedure for efficient contouring and a set of optimization constraints to meet the dose volume histogram criteria. Templates were created in our treatment planning system for structures, isodose levels, optimization constraints, and plan report. This study reviews our first 20 high dose rate Contura breast treatment plans. We followed our standardized procedure for contouring, planning, and second checking. The established dose volume histogram criteria were successfully met for all plans. For the cases studied here, the balloon-skin and balloon-ribs distances ranged between 5 and 43 mm and 1 and 33 mm, respectively; air{sub s}eroma volume/PTV{sub E}val volume≤5.5% (allowed≤10%); asymmetry<1.2 mm (goal≤2 mm); PTV{sub E}val V90%≥97.6%; PTV{sub E}val V95%≥94.9%; skin max dose≤98%Rx; ribs max dose≤137%Rx; V150%≤29.8 cc; V200%≤7.8 cc; the total dwell time range was 225.4 to 401.9 seconds; and the second check agreement was within 3%. Based on this analysis, more appropriate ranges for the total dwell time and balloon diameter tolerance were found. Three major problems were encountered: balloon migration toward the skin for small balloon-to-skin distances, lumen obstruction, and length change for the flexible balloon. Solutions were found for these issues and our standardized procedure and checklists were updated accordingly. Based on our review of these cases, the use of checklists resulted in consistent results, indicating good coverage for the target without sacrificing the critical structures. This review helped us to refine our standardized procedure and update our checklists.

  18. Study for HDR cross-link for formation flight satellite systems

    Science.gov (United States)

    Nishinaga, Nozomu; Takayama, Yoshihisa; Takahashi, Takashi; Ogawa, Yasuo; Kubooka, Toshihiro; Umehara, Hiroaki

    2003-07-01

    In this paper we studied about optical and millimeter radio wave cross-link for formation flight communication satellite system in a geostationary orbit. In formation flight system, since the distance among the satellites becomes short compared with the conventional inter satellite comunication link, the size and the weight of the communication system can be reduced. If the high data rate cross-link among the satellites which is equal to the whole transponder bandwidth can be established, the functionally distributed communications satellite system can be constructed. Then, by exchanging a part of the satellite system without the physical contact, in other words, by exchange some old satellites and new ones, the fully reconfigurable and long lifetime (from the point of the function) satellite communication system which can follow the paradigm shift in the terrestrial communications technology can be realize. On the other hand, however, since the maximum of relative angle error among two satellites is enlarged, the tracking becomes difficult. In this study, it turns the electric power which is gotten from the shortening the distance to making beam width large. Here, we examine communication among two satellites (10Km distance) where the data rate is 1Gbps.

  19. Advantages of high-dose rate (HDR) brachytherapy in treatment of prostate cancer

    Science.gov (United States)

    Molokov, A. A.; Vanina, E. A.; Tseluyko, S. S.

    2017-09-01

    One of the modern methods of preserving organs radiation treatment is brachytherapy. This article analyzes the results of prostate brachytherapy. These studies of the advantages of high dose brachytherapy lead to the conclusion that this method of radiation treatment for prostate cancer has a favorable advantage in comparison with remote sensing methods, and is competitive, preserving organs in comparison to surgical methods of treatment. The use of the method of polyfocal transperineal biopsy during the brachytherapy session provides information on the volumetric spread of prostate cancer and adjust the dosimetry plan taking into account the obtained data.

  20. Assessment of the implant geometry in fractionated interstitial HDR breast brachytherapy using an electromagnetic tracking system.

    Science.gov (United States)

    Kellermeier, Markus; Fietkau, Rainer; Strnad, Vratislav; Bert, Christoph

    During the partial-breast treatment course by interstitial brachytherapy, electromagnetic tracking (EMT) was applied to measure the implant geometry. Implant-geometry variation, choice of reference data, and three registration methods were assessed. The implant geometry was measured in 28 patients after catheter implantation (EMTbed), during CT imaging (EMTCT), and in each of up to n = 9 treatment fractions (EMTF(k), k = 1, 2,… n). EMTF(k) were registered to the planned implant reconstruction (CTplan) by using all dwell positions (DPs), the button centers, or three fiducial sensors on the patient's skin. Variation in implant geometry obtained from EMTF(k) was assessed for EMTbed, EMTCT, and CTplan. EMT was used to measure 3932 catheters. A duration of 6.5 ± 1.7 min was needed for each implant measurement (mean, 17 catheters) plus setup of the EMT system. Data registration based on the DP deviated significantly lower than registration on button centers or fiducial sensors. Within a registration group, there was a geometry in high-dose-rate interstitial brachytherapy breast treatments. EMTbed, EMTCT, and CTplan data can serve as reference for assessment of implant changes. Copyright © 2017 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  1. Construction of a anthropomorphic phantom for dose measurement in hands in brachytherapy procedures; Construccion de un fantoma antropomorfico para mediciones de dosis en manos en procedimientos de braquiterapia

    Energy Technology Data Exchange (ETDEWEB)

    Papp, Cinthia M., E-mail: cinthia_papp@yahoo.com.ar [Comision Nacional de Energia Atomica (IH/UNCUYO/CNEA), Mendoza (Argentina). Universidad Nacional de Cuyo. Instituto Balseiro; Ortiz, Arnulfo; Alvarez, Guillermo, E-mail: arnot@gmail.com, E-mail: galvarez@fuesmen.edu.ar [Fundacion Escuela de Medicina Nuclear (FUESMEN), Mendoza (Argentina)

    2013-11-01

    The main objective of this work was to show the differences between the dose value measured by dosimeter endpoint and the values measured in different points inside the hand during brachytherapy procedures. For this, the procedures involved in the handling of sources were analyzed and the simulated using an anthropomorphic phantom hand.

  2. Prototypes of phosphorus-32 sealed sources for use in Brachytherapy; Prototipo de fuente radiactiva de fosforo para uso medico en braquiterapia

    Energy Technology Data Exchange (ETDEWEB)

    Anaya Garro, Olgger; Vela Mora, Mariano; Revilla Silva, Angel Revilla [Instituto Peruano de Energia Nuclear (IPEN), Lima (Peru)]. E-mail: oanaya@ipen.gob.pe; mvela@ipen.gob.pe; arevilla@ipen.gob.pe

    2005-07-01

    It has developed prototypes of phosphorus-32 sealed sources for use in Brachytherapy. This one was made in two stages, at the first one, we designed and constructed the container (capsule), the filling system and the sealed system; at the second one, we made the irradiation of the capsules containing the 'target'. The prototypes was made of aluminum in cylindrical geometry. During the irradiation test was made using two different dimensions: one of 1 mm outer diameter and 1 cm length and another one of 0.8 mm outer diameter and 5 mm length. They were radiated in the core of the RP-10 research reactor, at 7.93 x10{sup 13} n/cm{sup 2}.s thermal neutron flux during 27 operation cycles. Activities of 144.53 MBq (3.91 mCi) and 107.67 MBq (2.91 mCi) was obtained for each case. This activities are adequate to restenosis and for some tumors treatment. We can observed that the capsules irradiated passed visual inspection in its physical integrity (leakage and geometry). It has been demonstrated, that the beta radiation for his minor power of penetration and its high interaction, causes major local damage to the malignant tissue, minimizing the damage of the healthy surrounding tissues. It has been advisable to use for the treatment of illnesses of the circulatory system and some tumors. At the present, the source of strontium-90 are the most beta ray source used, but of this one are obtained as fission product of uranium target, where valuable radioactive waste is generated, whereas if we were using phosphorus-32 that we propose, radioactive waste would not be generated since it would take place directly as sealed source, for reaction (n, {beta}). (author)

  3. Dose optimization in simulated permanent interstitial implant of prostate brachytherapy; Otimizacao de dose em implantes intersticiais permanentes simulados de braquiterapia de prostata

    Energy Technology Data Exchange (ETDEWEB)

    Faria, Fernando Pereira de

    2006-07-01

    Any treatment of cancer that uses some modality of radiotherapy is planned before being executed. In general the goal in radiotherapy is to irradiate the target to be treated minimizing the incidence of radiation in healthy surrounding tissues. The planning differ among themselves according to the modality of radiotherapy, the type of cancer and where it is located. This work approaches the problem of dose optimization for the planning of prostate cancer treatment through the modality of low dose-rate brachytherapy with Iodine 125 or Palladium 103 seeds. An algorithm for dose calculation and optimization was constructed to find the seeds configuration that better fits the relevant clinical criteria such as as the tolerated dose by the urethra and rectum and the desired dose for prostate. The algorithm automatically finds this configuration from the prostate geometry established in two or three dimensions by using images of ultrasound, magnetic resonance or tomography and from the establishment of minimum restrictions to the positions of the seeds in the prostate and needles in a template. Six patterns of seeds distribution based on clinical criteria were suggested and tested in this work. Each one of these patterns generated a space of possible seeds configurations for the prostate tested by the dose calculation and optimization algorithm. The configurations that satisfied the clinical criteria were submitted to a test according to an optimization function suggested in this work. The configuration that produced maximum value for this function was considered the optimized one. (author)

  4. Use of Monte Carlo Methods for determination of isodose curves in brachytherapy; Uso de tecnicas Monte Carlo para determinacao de curvas de isodose em braquiterapia

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, Jose Wilson

    2001-08-01

    Brachytherapy is a special form of cancer treatment in which the radioactive source is very close to or inside the tumor with the objective of causing the necrosis of the cancerous tissue. The intensity of cell response to the radiation varies according to the tissue type and degree of differentiation. Since the malign cells are less differentiated than the normal ones, they are more sensitive to the radiation. This is the basis for radiotherapy techniques. Institutes that work with the application of high dose rates use sophisticated computer programs to calculate the necessary dose to achieve the necrosis of the tumor and the same time, minimizing the irradiation of tissues and organs of the neighborhood. With knowledge the characteristics of the source and the tumor, it is possible to trace isodose curves with the necessary information for planning the brachytherapy in patients. The objective of this work is, using Monte Carlo techniques, to develop a computer program - the ISODOSE - which allows to determine isodose curves in turn of linear radioactive sources used in brachytherapy. The development of ISODOSE is important because the available commercial programs, in general, are very expensive and practically inaccessible to small clinics. The use of Monte Carlo techniques is viable because they avoid problems inherent to analytic solutions as, for instance , the integration of functions with singularities in its domain. The results of ISODOSE were compared with similar data found in the literature and also with those obtained at the institutes of radiotherapy of the 'Hospital do Cancer do Recife' and of the 'Hospital Portugues do Recife'. ISODOSE presented good performance, mainly, due to the Monte Carlo techniques, that allowed a quite detailed drawing of the isodose curves in turn of linear sources. (author)

  5. Ruthenium-106 brachytherapy for uveal melanomas. Preliminary results: a single institutional experience; Braquiterapia com rutenio-106 em melanomas uveais. Resultados preliminares: experiencia uni-instuticional

    Energy Technology Data Exchange (ETDEWEB)

    Dias, Rodrigo Souza; Giordani, Adelmo Jose; Segreto, Helena Regina Comodo; Segreto, Roberto Araujo [Universidade Federal de Sao Paulo/Escola Paulista de Medicina (Unifesp/EPM), Sao Paulo, SP (Brazil). Departamento de Medicina. Setor de Radioterapia ; Erwenne, Clelia Maria; Teixeira, Luiz Fernando [Universidade Federal de Sao Paulo/Escola Paulista de Medicina (UNIFESP/EPM), Sao Paulo, SP (Brazil). Dept. de Oftalmologia]. E-mail: segreto. dmed@epm.br

    2007-03-15

    Objective: To analyze the early response of uveal melanomas in patients treated with ruthenium-106 brachytherapy. Materials And Methods: In the period between April 2002 and July 2003, 20 patients diagnosed with uveal melanoma were submitted to ruthenium-106 brachytherapy. The calculated dose delivered at the apex of the tumor ranged between 55 Gy and 100 Gy. Patients with lesions greater than 5 mm were submitted to transpupillary thermotherapy concomitantly with ophthalmic plaque insertion. Results: As regards the lesions site, 75% of the lesions were located in the choroid, 15% in the iris, and the remainder 10% in the ciliary body. In a median 19-month-follow-up, the progression-free survival for brachytherapy was 69%, and 87% for associated brachytherapy and transpupillary thermotherapy. A significant tumor height reduction was observed after treatment. No patient was submitted to enucleation. Conclusion: Our preliminary results show that ruthenium-106 brachytherapy is an appropriate method for conservative treatment of patients with uveal melanomas in terms of local management, ocular and visual acuity preservation with an acceptable complications incidence rate. (author)

  6. Efectividad de las protesis intrabucales protectoras emplomadas en teleterapia y braquiterapia.(DOSSIER CIENCIAS BASICAS, MEDICINA ORAL, BIOTECNOLOGIA Y BIOINFORMATICA EN ODONTOLOGIA)

    National Research Council Canada - National Science Library

    Rosales Ibanez, Raul; Montalvo Ramirez, Gustavo; de Lima Moreno, Javier; Sanchez-Rubio Carrillo, Ricardo Manuel; Estrada Esquivel, Blanca Estela; Sanchez-Rubio Carrillo, Raul Armando

    2014-01-01

    Antecedentes: se presentan las primeras fases de pruebas in vitro que refutan la hipotesis de que el material de 2-3 mm de plomo utilizado como protector en protesis radiferas, durante radioterapia en pacientes...

  7. High dose rate brachytherapy in the treatment of endometrium carcinoma; Tratamento de cancer do endometrio com braquiterapia de alta taxa de dose

    Energy Technology Data Exchange (ETDEWEB)

    Aisen, Salim; Carvalho, Heloisa A.; Nadalin, Wladimir [Sao Paulo Univ., SP (Brazil). Hospital das Clinicas. Servico de Radioterapia

    1995-11-01

    One hundred and four patients with histologic proven carcinoma of the endometrium were referred to our department for treatment. The median age was 65.5 years and the median follow-up was 38 months. Ninety-five was pos-menopaused, 7 peri and 2 were pre-menopaused. Sixteen patients were staged (pos-surgery) IA, 5 GI, 8 G2 and 3 G3. Thirty and four stage IB, 10 G1, 18 G2 and 1 G3. Twenty-five were stage IC, 9 G1, 9 G2 and 7 G3. Six were stage IIA, 2 GI, 3 G2 and 1 G3. Eight were stages IIB, 1 G1,3 G2 and 4 G3. Nine were stage IIA, 2 GI, 5 G2, 2 G3. Three were stage IIIB, 2 GI and 1 G2. One was stage III C G3, and two were IVA G3. Depending of the extension of the disease, patients underwent total hysterectomy and bilateral salpino-ooforectomy, or total hysterectomy and bilateral salpino-ooforectomy plus omentectomy or Werthein-Megs technique. All the patients IA and IB have no evidence of disease (NED). Twenty-four patients IC are NED and one presented distant metastasis. From the IIB patients, 6 are NED, one shown progressive local disease (PLD) and one died from disease. From the patients IIIA, 7 are NED, one DM and one PLD. From the IIIB patients one is NED and TWO are PLD. From the IIIC patient is NED two months after treatment and the IVA patients are NED three and four month after treatment. Eight patients have shown mild complications of treatment. The results of survival and complications are similar to the therapeutic with low dose rate brachytherapy, with the advantage of an outpatient treatment, without the inconvenience of impatient regime. (author). 22 refs., 1 tab.

  8. Comparison between calculation methods of dose rates in gynecologic brachytherapy; Comparacion entre metodos de calculo de tasa de dosis en braquiterapia ginecologica8

    Energy Technology Data Exchange (ETDEWEB)

    Vianello, E.A.; Biaggio, M.F.; Dr, M.F.; Almeida, C.E. de [Laboratorio de Ciencias Radiologicas- (L.C.R.)-D.B.B.- UERJ- R. Sao Francisco Xavier, 524- Pav. HLC- sala 136- CEP 20550-013 Rio de Janeiro (Brazil)

    1998-12-31

    In treatments with radiations for gynecologic tumors is necessary to evaluate the quality of the results obtained by different calculation methods for the dose rates on the points of clinical interest (A, rectal, vesicle). The present work compares the results obtained by two methods. The Manual Calibration Method (MCM) tri dimensional (Vianello E., et.al. 1998), using orthogonal radiographs for each patient in treatment, and the Theraplan/T P-11 planning system (Thratonics International Limited 1990) this last one verified experimentally (Vianello et.al. 1996). The results show that MCM can be used in the physical-clinical practice with a percentile difference comparable at the computerized programs. (Author)

  9. Experience in the safety use of a brachytherapy by manual afterloading; Experiencia en el uso seguro de un sistema de braquiterapia por carga diferida manual

    Energy Technology Data Exchange (ETDEWEB)

    Marco Hernandez, Jose M.; Flores Caro, Jorge; Morales Jorge, Leonel [Instituto Nacional de Oncologia y Radiobiologia, La Habana (Cuba). Seccion de Proteccion Radiologica

    2001-07-01

    Early in the twenty century started in Cuba the use of Radium Brachytherapy for malign neoplasms of the uterine cervix and endometrium, using the Manchester system. This became the main source of personal collective dose and unwanted radiological incidents. In 1989 this method was substituted by Amersham 137 Cs manual afterloading system. The purpose of this work has been to evaluate the impact of the new system in the optimization of this practice in the effective dose and collective effective dose distributions, during ten years, comparing these results of both systems and sources. Monitoring of personnel was done using film bages and recently by means of TLD(Li Fl:Mg). Highest annual exposures with 137 Cs reached only once to 26,2 mSv as result of local rules violation. Technologists, nurses and ward service personnel recorded 14%, 11%, and 29% of the ICRP annual effective dose limit. Thanks to the afterloading system, organisative rules and use of shielded containers, it was achieved a 79% reduction in the collective effective dose. (author)

  10. Dosimetric study for characterization of a postal system of quality control in brachytherapy; Estudo dosimetrico para caracterizacao de um sistema postal de controle de qualidade em braquiterapia

    Energy Technology Data Exchange (ETDEWEB)

    Alves, Victor Gabriel Leandro, E-mail: vgalves@inca.gov.b [Instituto Nacional do Cancer (INCa), Rio de Janeiro, RJ (Brazil); Queiroz Filho, Pedro Pacheco de; Santos, Denison de Souza, E-mail: queiroz@ird.gov.b, E-mail: santosd@ird.gov.b [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Begalli, Marcia, E-mail: begalli@uerj.b [Universidade do Estado do Rio de Janeiro (IF/UERJ), RJ (Brazil). Inst. de Fisica

    2009-07-01

    This work presents a dosimetric study of a postal system, to be developed for measurements of brachytherapy. It was projected a PMMA phantom with orifices for insertion of the high dose {sup 192}Ir source and the T L dosemeters. The system was characterized with using of Monte Carlo simulations, using the dosimetric magnitudes defined at the T G-43 of AAPM, as function of radial dose g(f)

  11. Doses of radiation in the environment of patients undergoing treatment of ophthalmic brachytherapy; Dosis de radiaciones en el entorno de pacientes sometidos a tratamientos de braquiterapia oftalmica

    Energy Technology Data Exchange (ETDEWEB)

    Terron Leon, J. A.; Moreno Reyes, J. C.; Perales Molina, A.; Miras, H.; Ortiz, M.; Macias, J.

    2013-07-01

    This paper presents results for measures of dose made to different patient undergoing treatment with ophthalmic brachytherapy. The aim of these measures has been, on the one hand, verify assessments relating to radiation protection in the memory of the installation and, on the other hand, experimental measures that can serve to reduce the perception of the radiological risk professionals have. (Author)

  12. Applications of a statistical model to the dosimetry of brachytherapy linear sources; Aplicaciones de un modelo estadistico a la dosimetria dde fuentes de braquiterapia

    Energy Technology Data Exchange (ETDEWEB)

    Sabariego, M. P.; Lallena, A. M.; Porras, I.

    2011-07-01

    The dosimetry of photon brachytherapy sources often make use of simple analytical expressions with free parameters to fit experimental data or Monte Carlo simulation. Some planning systems make use of polynomials yi o exponential functions. By applying a statistical model developed by the authors-point source of photons that provides these functions, we try to describe the dosimetric parameters that characterize the linear brachytherapy sources by integrating them.

  13. Notes on the implementation of the TG-43 formalism in high-rate brachytherapy; Notas sobre la implementacion del formalismo TG-43 en braquiterapia de lata tasa

    Energy Technology Data Exchange (ETDEWEB)

    Sendon del Rio, J. R.; Gonzalez Ruiz, C.; Garcia Marcos, R.; Jimenez Rojas, R.; Lopez Bote, M. A.

    2011-07-01

    The TG-43 formalism is based on dosimetric parameters depend on the specific font design extracted from dose distributions calculated by Monte Carlo in water. Relatively easy to implement, yet provides a degree of uncertainty, making it necessary to verify the calculation algorithm in the planning system to assess its behavior.

  14. Validation of a computerized system plan for gynecological brachytherapy; Validacao de um sistema computadorizado de planejamento de braquiterapia de tumores ginecologicos

    Energy Technology Data Exchange (ETDEWEB)

    Vianello, Elizabeth A.; Biaggio, Maria de Fatima de; Almeida, Carlos Eduardo de [Instituto Nacional do Cancer, Rio de Janeiro, RJ (Brazil)]|[Universidade do Estado, Rio de Janeiro, RJ (Brazil). Dept. de Biofisica e Biometria. Lab. de Ciencias Radiologicas

    1996-12-31

    Comparative evaluations between experimental measurements obtained with an anthropomorphic pelvic phantom, and with results obtained manually and by Theraplan/TP-11 (5. version) for the same source distribution are presented. The dose rates at the point A, rectum and bladder are considered 5 refs., 1 fig., 2 tabs.

  15. Image-Guided High-Dose-Rate (HDR) Boost Localization Using MRI/MR Spectroscopy: A Correlation Study with Biopsy

    OpenAIRE

    Vigneault, Eric; Mbodji, Khaly; Racine, Louis G; Chevrette, Eric; Lavallee, Marie C; Martin, Andr?-Guy; Despres, Philippe; Beaulieu, Luc

    2016-01-01

    Purpose: The purpose of this study is to compare the blind interpretations of magnetic resonance imaging (MRI) sequences, diffusion-weighted imaging (DWI), apparent diffusion coefficient (ADC), mapping, and magnetic resonance spectroscopy (MRS) of the prostate, in comparison to prostate biopsy to identify a valid dominant intraprostatic lesion (DIL) for dose escalation using high-dose rate brachytherapy. Methods: MRI/MRS were performed on 20 patients with intermediate risk adenocarcinoma of t...

  16. Visual acuity-adaptive detail enhancement and shadow noise reduction for iCAM06-based HDR imaging

    Science.gov (United States)

    Lee, Geun-Young; Lee, Sung-Hak; Kwon, Hyuk-Ju; Sohng, Kyu-Ik

    2015-04-01

    An image appearance model is extremely useful for high-dynamic-range image (HDRI) rendering. However, the base-detail separation and the tone compression process for tonal control cause degradations in image quality. This study focuses on the de-saturation, reduced contrast, and noise problems in dark regions that occur through HDRI-rendering. First, we discuss de-saturation compensation using a bilateral filter that is based on the visual acuity characteristics of various illuminant levels. The edge stop function of the bilateral filter in iCAM06 is adaptively modified according to the illuminant information. Second, to reduce the magnified noise in the dark regions caused by tone mapping, the shadow regions are detected by an object's intensity and illuminant level, and then the noise of the detected regions is reduced using a luminance-adaptive coring function. Finally, we confirmed the enhanced color saturation, image contrast, and reduced noise in shadow regions through the application of the proposed methods.

  17. A detailed dosimetric comparison between manual and inverse plans in HDR intracavitary/interstitial cervical cancer brachytherapy.

    Science.gov (United States)

    Trnková, Petra; Baltas, Dimos; Karabis, Andreas; Stock, Markus; Dimopoulos, Johannes; Georg, Dietmar; Pötter, Richard; Kirisits, Christian

    2010-12-01

    The purpose of this study was to compare two inverse planning algorithms for cervical cancer brachytherapy and a conventional manual treatment planning according to the MUW (Medical University of Vienna) protocol. For 20 patients, manually optimized, and, inversely optimized treatment plans with Hybrid Inverse treatment Planning and Optimization (HIPO) and with Inverse Planning Simulated Annealing (IPSA) were created. Dosimetric parameters, absolute volumes of normal tissue receiving reference doses, absolute loading times of tandem, ring and interstitial needles, Paddick and COIN conformity indices were evaluated. HIPO was able to achieve a similar dose distribution to manual planning with the restriction of high dose regions. It reduced the loading time of needles and the overall treatment time. The values of both conformity indices were the lowest. IPSA was able to achieve acceptable dosimetric results. However, it overloaded the needles. This resulted in high dose regions located in the normal tissue. The Paddick index for the volume of two times prescribed dose was outstandingly low. HIPO can produce clinically acceptable treatment plans with the elimination of high dose regions in normal tissue. Compared to IPSA, it is an inverse optimization method which takes into account current clinical experience gained from manual treatment planning.

  18. A detailed dosimetric comparison between manual and inverse plans in HDR intracavitary/interstitial cervical cancer brachytherapy

    Directory of Open Access Journals (Sweden)

    Johannes Dimopoulos

    2010-01-01

    Full Text Available Purpose: The purpose of this study was to compare two inverse planning algorithms for cervical cancer brachytherapy and a conventional manual treatment planning according to the MUW (Medical University of Vienna protocol.Material and methods: For 20 patients, manually optimized, and, inversely optimized treatment plans with Hybrid Inverse treatment Planning and Optimization (HIPO and with Inverse Planning Simulated Annealing (IPSA were created. Dosimetric parameters, absolute volumes of normal tissue receiving reference doses, absolute loading times of tandem, ring and interstitial needles, Paddick and COIN conformity indices were evaluated.Results: HIPO was able to achieve a similar dose distribution to manual planning with the restriction of high dose regions. It reduced the loading time of needles and the overall treatment time. The values of both conformity indices were the lowest. IPSA was able to achieve acceptable dosimetric results. However, it overloaded the needles.This resulted in high dose regions located in the normal tissue. The Paddick index for the volume of two times prescribed dose was outstandingly low.Conclusions: HIPO can produce clinically acceptable treatment plans with the elimination of high dose regions in normal tissue. Compared to IPSA, it is an inverse optimization method which takes into account current clinical experience gained from manual treatment planning.

  19. Design and Implementation of a Complementary Treatment Planning Software for the GZP6 HDR Brachytherapy System (GZP6 CTPS

    Directory of Open Access Journals (Sweden)

    Sanaz Hariri Tabrizi

    2011-03-01

    Full Text Available Introduction: Brachytherapy is one of the most common treatment modalities for gynecological cancer. The GZP6 brachytherapy system is one of the devices utilized in Iran. It has been considered particularly due to its low cost compared to other more complete and established systems. This system has some deficiencies including lack of a treatment planning software for non-predefined treatments, inability to change the gradually changeable dosimetric variables and using a point source estimation in dose calculation. This report presents a complementary treatment planning software (CTPS to the system’s own dedicated program. Material and Methods: First, the dosimetric characteristics of three GZP6 sources were calculated based on the TG-43 protocol using the MCNP4C Monte Carlo code. Then, the calculated dose distribution around the implanted applicators, based on the selected dwell positions and dwell times, was shown in a graphical user interface (GUI written using the MATLAB software. Results: The computation uncertainty in the resulting TG-43 parameters was about 1% and the calculated parameters were in good agreement with similar studies on cobalt-60 source dosimetry. Furthermore, the GUI is prepared as a user-friendly executable file which can be installed on any operating system. Discussion and Conclusion: Since different patients have distinct anatomy and physical conditions, a program for non-predefined situations of source arrangement is necessary. Using GZP6 CTPS can satisfy this requirement.

  20. Dosimetric evaluation of a combination of brachytherapy applicators for uterine cervix cancer with involvement of the distal vagina

    OpenAIRE

    Guimarães, Roger Guilherme Rodrigues; Carvalho, Heloisa de Andrade; Stuart, Silvia Radwanski; Rubo, Rodrigo Augusto; Seraide, Rodrigo Migotto

    2009-01-01

    OBJETIVO: Avaliar uma alternativa de braquiterapia para tumores do colo uterino acometendo a porção distal da vagina, sem aumentar os riscos de toxicidade. MATERIAIS E MÉTODOS: Estudo teórico comparando três diferentes aplicadores de braquiterapia intracavitária de alta taxa de dose: sonda intrauterina e cilindro vaginal (SC); sonda e anel associado ao cilindro vaginal (SA+C) e um aplicador virtual com sonda, anel e cilindro vaginal em um único conjunto (SAC). Foram prescritas doses de 7 Gy n...

  1. Study and development of methodology for radioactive iodine fixation in polymeric substrate for manufacturing sources used in brachytherapy; Estudo e desenvolvimento de metodologia para fixacao de iodo radioativo em substrato polimerico para confeccao de fontes utilizadas em braquiterapia

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Bruna T.; Souza, Carla D.; Benega, Marcos A.G. and others, E-mail: bteigarodrigues@gmail.com, E-mail: carladdsouza@yahoo.com.br, E-mail: marcosagbenega@gmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Tecnologia das Radiacoes

    2014-07-01

    According global estimates of Globocan 2012 project of the International Agency for Research of Cancer, of the World Health Organization, there were 14,1 million new cases of cancer and a total of 8,2 million deaths from cancer. Also show that in 2030, the overall load will be 21,4 million new cases and 13,2 million cancer deaths. One of the prostate cancer therapy is brachytherapy, used in early and middle stages of the disease. It is made with the introduction of seeds with radioactive material within the tumor or in nearby regions, affecting the minimum surrounding tissues. The aim of this work is the study and developing the deposition of radioactive iodine on the polymeric substrate method, and an analysis relating the efficiency of the method to implementation in the laboratory of brachytherapy from IPEN. Iodine-125 is adsorbed on an epoxy resin solution. The objective of this study is to offer a new proposal for seeds. The results will give the data for the radiation protection and the procedures for radioactive waste management.

  2. Influence of modifications in the positioning of phantoms in the Monte Carlo computational simulation of the prostate brachytherapy; Influencia de alteracoes no posicionamento de fantomas nas simulacoes computacionais Monte Carlo de braquiterapia de prostata

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, Antonio Konrado de Santana; Vieira, Jose Wilson, E-mail: konrado.radiologia@gmail.co, E-mail: jose.wilson59@uol.com.b [Instituto Federal de Educacao, Ciencia e Tecnologia (IFPE), Recife, PE (Brazil); Costa, Kleber Souza Silva [Faculdade Integrada de Pernambuco (FACIPE), Recife, PE (Brazil); Lima, Fernando Roberto de Andrade, E-mail: falima@cnen.gov.b [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

    2011-07-01

    Radiotherapy simulation procedures using Monte Carlo methods have shown to be increasingly important to the improvement of cancer fighting strategies. Within this context, brachytherapy is one of the most used methods to ensure better life quality when compared to other therapeutic modalities. These procedures are planned with the use of sectional exams with the patient in lying position. However, it is known that alteration of body posture after the procedure has an influence in the localization of many organs. This study had the aim to identify and to measure the influence of such alterations in MC brachytherapy simulations. In order to do so, prostate brachytherapy with the use of Iodine-125 radionuclide was chosen as model. Simulations were carried out with 108 events using EGSnrc code associated to MASH phantom in orthostatic and supine positions. Significant alterations were found, especially regarding bladder, small intestine and testicles. (author)

  3. Dosimetric comparison between a planning system and Radiochromic-EBT2 films in surface brachytherapy treatments of high rate; Comparacion dosimetrica entre un sistema de planificacion y peliculas radiocromicas EBT2 en tratamientos de braquiterapia superficial de alta tasa

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez Ramos, S. M.; Carrasco Herrera, M. a.; Vicent, D.; Rodriguez, C.; Herrador, M.

    2013-07-01

    The objective of this work is to study a situation in which, the accuracy of the calculation of the planner may be limited, superficial brachytherapy treatment. It has relative to the dose obtained with the planner with that obtained with film radiochromic EBT2. (Author)

  4. Evaluation of failure modes of computerized planning phase of interstitial implants with high dose rate brachytherapy using HFMEA; Avaliacao dos modos de falha do planejamento computadorizado em implantes intersticiais com braquiterapia de alta taxa de dose usando HFMEA

    Energy Technology Data Exchange (ETDEWEB)

    Biazotto, Bruna; Tokarski, Marcio, E-mail: bruna@ceb.unicamp.br [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Centro de Engenharia Biomedica

    2014-08-15

    This paper evaluates the failure modes of the computerized planning step in interstitial implants with high dose rate brachytherapy. The prospective tool of risk management Health Care Failure Mode and Effects Analysis (HFMEA) was used. Twelve subprocesses were identified, and 33 failure modes of which 21 justified new safety actions, and 9 of them were intolerable risks. The method proved itself useful in identifying failure modes, but laborious and subjective in their assessment. The main risks were due to human factors, which require training and commitment of management to their mitigation. (author)

  5. Measure of the uncertainty associated with the reconstruction of applicators in adaptive guided brachytherapy by resonance; Medida de la incertidumbre asociada a la reconstruccion de aplicadores en braquiterapia adaptativa guiada por resonancia

    Energy Technology Data Exchange (ETDEWEB)

    Torres Pozas, S.; Federico, M.; Perez Molina, J. L.; Marti Asenjo, J.; Sanchez Carrascal, M.; Macias verde, D.; Ruiz Egea, E.; Lara Jimenez, P.; Martin Oliva, R.

    2013-07-01

    The objective of this study is to assess the uncertainty introduced in the process to rebuild the catheters using three methods, manual reconstruction from a template elaborate service, auto-rebuild with the software included in the TPS and reconstruction from radiopaque mannequins in CT and subsequent merger. (Author)

  6. Calibration of a {sup 19} {sup 2}Ir source for high dose brachytherapy using various techniques; Calibracion de una fuente de {sup 192} Ir para braquiterapia de alta tasa de dosis mediante diversas tecnicas

    Energy Technology Data Exchange (ETDEWEB)

    Montilla Prieto, Tedicel C., E-mail: tcdicel@gmaiLcam [Instituto de Oncologia Dr. Miguel Perez Carreno, Barbula (Venezuela, Bolivarian Republic of). Departamento de Fisica y Dosimetria; Padron Rivero, Alvaro D., E-mail: alvarodpadronr@yahoo.com.ve [Universidad de Carabobo, Barbula (Venezuela, Bolivarian Republic of). Facultad de Ciencias de la Salud. Departamento de Ciencias Fisiologicas

    2013-10-01

    In this research we studied three experimental procedures for calibration of a source of {sup 192}Ir to high dose rate for clinical brachytherapy use, and thus were compared and analysis of the advantages and disadvantages of each. For this study we quantified the value of the current kerma rate reference in air by three procedures: source calibration using a well chamber, with an cylindrical ionization chamber in air, and a cylindrical ionization chamber on a phantom, and this magnitude was compared with the value provided by the manufacturer of the source and thereby obtaining the deviation corresponding . Thus, it was found that the deviation corresponding to the source calibration making use of a well chamber, remained within tolerance, while the cylindrical ionization chamber in air and on phantom exceeded the standards established in some documents. However, although both the measurement in air and in the phantom are the procedures for the final calibration source, these can be used to verify that the delivered dose are in tolerance.

  7. Determination of air kerma standard of high dose rate {sup 192}Ir brachytherapy source; Determinacao da taxa de kerma no ar de referencia para {sup 192}Ir de alta taxa de dose para braquiterapia

    Energy Technology Data Exchange (ETDEWEB)

    Pires, E.J.; Alves, C.F.E.; Leite, S.P.; Magalhaes, L.A.G.; David, M.G.; Almeida, C.E. de, E-mail: cfealves@gmail.com [Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, RJ (Brazil). Lab. de Ciencias Radiologicas; Di Prinzio, R. [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2015-07-01

    This paper presents the methodology developed by the Laboratorio de Ciencias Radiologicas and presently in use for determining of the air kerma standard of {sup 192}Ir high dose rate sources to calibrate well-type chambers. Uncertainty analysis involving the measurements procedure are presented. (author)

  8. Determination of the chemical yield on the Fricke dosimetry for {sup 192}Ir sources used in brachytherapy; Determinacao do rendimento quimico na dosimetria Fricke para fontes de {sup 192}Ir usadas em braquiterapia

    Energy Technology Data Exchange (ETDEWEB)

    David, M.G.; Albuquerque, M.A.G.; Almeida, C.E. de, E-mail: marianogd08@gmail.com [Universidade do Estado do Rio de Janeiro (LCR/UERJ), Rio de Janeiro, RJ (Brazil). Lab. de Ciencias Radiologicas; Salata, C. [Comissao Nacional de Energia Nuclear (CNEN), Rio de Janeiro, RJ (Brazil); Rosado, P.H. [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2015-07-01

    With the aim of developing a primary standard for the absorbed dose to water, for the {sup 192}Ir sources used in high dose rate brachytherapy, this work focuses on the determination of the chemical yield, G(Fe{sup +3}), using Fricke dosimetry, for the energy of those sources . The G(Fe{sup +3}) were determined the for three qualities of x-ray beams (150, 250 and 300 kV ) and for {sup 60}Co energy. The G(Fe{sup +3}) value for the average energy of {sup 192}Ir was obtained by linear fit, the found value was 1,555 ± 0,015 μmol/J. (author)

  9. Applicability of a prototype for determination of absorbed dose using brachytherapy equipment with Ir-192 sources; Aplicabilidade de um prototipo para determinacao da dose absorvida utilizando equipamentos de braquiterapia com fontes de IR-192

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Vivianne Lucia Bormann; Almeida, Mayara Gabriella Oliveira de; Vieira, Rafaela Etelvina de Amorim; Silva, Waldecy Ananias da; Nascimento, Rizia Keila, E-mail: vlsouza@cnen.gov.br, E-mail: mayaradqf@hotmail.com, E-mail: rodriguesss@hootmail.com, E-mail: waldecy@cnen.gov.br, E-mail: riziakeila@hotmail.com [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

    2014-07-01

    This work aims at the development and improvement of a device to perform the absolute dosimetry sources of Ir-192 using the Fricke solution contained in a flask. The Fricke solution used was prepared using amounts of ferrous ammonium sulfate, sodium chloride and sulfuric acid, diluted with water tri distilled pre-established in the literature. The spectrophotometer used was a UV-VIS spectrophotometer (Beckman DU-640 Counter) for measuring the optical density at wavelength 304 nm. The calculation for determining the radial dose takes into account the radial distance and the angle formed with the transverse axis of the source. As the results obtained can be seen that the states of Pernambuco, Ceara, Paraiba e Piaui are in accordance with the recommendations of international standards of the International Atomic Energy Agency (IAEA), which considers not acceptable a difference greater than 5% of prescribed dose and measured dose.

  10. Staff dose of hospitalization in the treatment of patients in ophthalmic brachytherapy with 125 I; Dosis al personal de hospitalizacion en el tratamiento de pacientes de braquiterapia oftalmica con I-125

    Energy Technology Data Exchange (ETDEWEB)

    Terron Leon, J. A.; Gomez Palacios, M.; Moreno Reyes, J. C.; Perales Molina, A.

    2013-07-01

    The objective of this work, therefore, has been the evaluation of the dose levels which nursing staff can receive in care for ophthalmic brachytherapy patients treated with 125 I from measurements made on the same, evaluating, in an experimental way, job security following the PR rules laid down for these treatments. (Author)

  11. Analysis of the uncertainty of semiconductor diodes in dosimetry in vivo of brachytherapy treatments; Analisis de la incertidumbre de diodos semiconductores en dosimetria in vivo de tratamientos de braquiterapia

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, K.; Rodriguez, P.; Prieto, D.; Esteve, S.; Colmenares, R.; Bejar, M. J.; Ordonez, J.; Capuz, B.; Moris, R.

    2013-07-01

    Brachytherapy involves the administration of high doses in some parts of healthy tissue, especially in the organ at risk coming to the region of prescription, as it is the case of the rectum and bladder in various gynecological treatments. The possibility of trying to know the actual dose in vivo through the use of dosimeters of semiconductor diode could be. However, to know if you can have certainty in these measures it is necessary to establish the uncertainty previously. The objective of this work consists in estimating the intrinsic uncertainty of diodes and compare it with other dosimetry uncertainties such as the one given the displacement of these between the planning and administration of treatment. (Author)

  12. Interstitial brachytherapy with 192-IR in treatment of recurrent malignant primary brain tumors. Braquiterapia intersticial con iridio-192 en el tratamiento de recidivas de tumores cerebrales tras cirugia y radioterapia

    Energy Technology Data Exchange (ETDEWEB)

    Cardenes, R.; Martinez, R.; Victoria, C.; Nuez, L.; Clavo, B.; Sancedo, G. (Clinica Puerta de Hierro. Madrid (Spain))

    1994-01-01

    Seven patients with recurrent malignant primary brain tumors after surgery and radiation therapy were treated at the Clinica Puerta de Hierro (Madrid) by interstitial brachytherapy with 192-Ir sources. Implantations were performed using computerized tomography and dose prescription were determined following the Paris system rules for interstitial implants. The means dose deliberated was 50 to 65 Gy to the reference isodoses. At the last follow-up all patients except for one are alive and without evidence of progression of the disease. (Author) 35 refs.

  13. Dosimetric evaluation of a combination of brachytherapy applicators for uterine cervix cancer with involvement of the distal vagina; Avaliacao dosimetrica de uma combinacao de aplicadores para braquiterapia de tumores do colo uterino com acometimento da porcao distal da vagina

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, Roger Guilherme Rodrigues [Real e Benemerita Sociedade Portuguesa de Beneficencia, Sao Paulo, SP (Brazil). Servico de Radioterapia Estereotactica; Carvalho, Heloisa de Andrade; Stuart, Silvia Radwanski; Rubo, Rodrigo Augusto [Universidade de Sao Paulo (USP), SP (Brazil). Hospital das Clinicas. Servico de Radioterapia], e-mail: handrade@hcnet.usp.br; Seraide, Rodrigo Migotto [Centro de Oncologia Campinas, SP (Brazil)

    2009-07-15

    Objective: To evaluate an alternative brachytherapy technique for uterine cervix cancer involving the distal vagina, without increasing the risk of toxicity. Materials And Methods: Theoretical study comparing three different high-dose rate intracavitary brachytherapy applicators: intrauterine tandem and vaginal cylinder (TC); tandem/ring applicator combined with vaginal cylinder (TR+C); and a virtual applicator combining both the tandem/ring and vaginal cylinder in a single device (TRC). Prescribed doses were 7 Gy at point A, and 5 Gy on the surface or at a 5 mm depth of the vaginal mucosa. Doses delivered to the rectum, bladder and sigmoid colon were kept below the tolerance limits. Volumes covered by the isodoses, respectively, 50% (V50), 100% (V100), 150% (V150) and 200% (V200) were compared. Results: Both the combined TR+C and TRC presented a better dose distribution as compared with the TC applicator. The TR+C dose distribution was similar to the TRC dose, with V150 and V200 being about 50% higher for TR+C (within the cylinder). Conclusion: Combined TR+C in a two-time single application may represent an alternative therapy technique for patients affected by uterine cervix cancer involving the distal vagina. (author)

  14. Synthesis and characterization of hydroxyapatite porous matrixes for application as radiation sources in brachytherapy; Sintese e caracterizacao de matrizes porosas de hidroxiapatita para aplicacao como fontes radioativas em braquiterapia

    Energy Technology Data Exchange (ETDEWEB)

    Lacerda, Kassio Andre; Lameiras, Fernando Soares; Silva, Viviane Viana [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)]. E-mail: kassiolacerda@yahoo.com.br

    2006-04-15

    Porous ceramic materials based on calcium phosphate compounds (CPC) have been studied aiming at different biomedical applications such as implants, drug delivery systems and radioactive sources for brachytherapy. Two kinds of hydroxyapatite (HAp) powders and their ceramic bodies were characterized by a combination of different techniques (X-rays diffraction and fluorescence, infrared spectrophotometry, BET method, thermal analysis, and scanning electron microscopy) to evaluate their physico-chemical and microstructural characteristics in terms of chemical composition, segregated phases, microstructure, porosity, and chemical and thermal stability. The results revealed that these systems presented potential for use as porous biodegradable radioactive sources able to be loaded with a wide range of radionuclides for cancer treatment by the brachytherapy technique. (author)

  15. Determination of factors through Monte Carlo method for Fricke dosimetry from {sup 192}Ir sources for brachytherapy; Determinacao por Monte Carlo de fatores para dosimetria Fricke de fontes de {sup 192}Ir para braquiterapia

    Energy Technology Data Exchange (ETDEWEB)

    David, Mariano Gazineu; Salata, Camila; Almeida, Carlos Eduardo, E-mail: marianogd08@gmail.com [Universidade do Estado do Rio de Janeiro (UERJ/LCR), Rio de Janeiro (Brazil). Lab. de Ciencias Radiologicas

    2014-07-01

    The Laboratorio de Ciencias Radiologicas develops a methodology for the determination of the absorbed dose to water by Fricke chemical dosimetry method for brachytherapy sources of {sup 192}Ir high dose rate and have compared their results with the laboratory of the National Research Council Canada. This paper describes the determination of the correction factors by Monte Carlo method, with the Penelope code. Values for all factors are presented, with a maximum difference of 0.22% for their determination by an alternative way. (author)

  16. Preparation of a program for the independent verification of the brachytherapy planning systems calculations; Confeccion de un programa para la verificacion independiente de los calculos de los sistemas de planificacion en braquiterapia

    Energy Technology Data Exchange (ETDEWEB)

    V Carmona, V.; Perez-Calatayud, J.; Lliso, F.; Richart Sancho, J.; Ballester, F.; Pujades-Claumarchirant, M.C.; Munoz, M.

    2010-07-01

    In this work a program is presented that independently checks for each patient the treatment planning system calculations in low dose rate, high dose rate and pulsed dose rate brachytherapy. The treatment planning system output text files are automatically loaded in this program in order to get the source coordinates, the desired calculation point coordinates and the dwell times when it is the case. The source strength and the reference dates are introduced by the user. The program allows implementing the recommendations about independent verification of the clinical brachytherapy dosimetry in a simple and accurate way, in few minutes. (Author).

  17. Quality control of brachytherapy system module Oncentra MasterPlan V3.3 planning; Control de calidad del modulo de braquiterapia del sistema de planificacion Oncentra MasterPlan V3.3

    Energy Technology Data Exchange (ETDEWEB)

    Monja Ray, P. de la; Torres Pozas, S.; Sanchez Carrascal, M.; Macias Verde, D.; Martin Oliva, R.

    2011-07-01

    We present the results of quality control carried out the planning system (SP) MasterPlan Oncentra Brachy, version 3.3 (Nucletron), on the occasion of its launch, following the recommendations proposed in the Protocol for quality control in planning systems therapy with ionizing radiation [SEFM, published by the Spanish Society of Medical Physics (SEFM) in 2005].

  18. Monte Carlo simulation of gynecologic brachytherapy treatment of high rate considering the heterogeneity; Simulacion Monte Carlo de un tratamiento de braquiterapia ginecologica de alta tasa teniendo en cuenta las heterogeneidades

    Energy Technology Data Exchange (ETDEWEB)

    Berenguer Serrano, R.; Rivera Jimenez, M.; Nunez Quintanilla, A. T.; Vara Olivas, V. de la; Gutierrez Perez, M.; Sabater Martin, S.

    2011-07-01

    The objective of this study was to compare the dosimetric distribution of gynecological brachytherapy treatment with high dose rate Ir-192 source as does a conventional planner versus dosimetric distribution obtained by Monte Carlo simulation taking into account (addition to the geometry of the source), gynecologic vaginal applicator (tube and vaginal cylinder or dome) and the anatomy of the patient. In particular we assessed the effect of the presence of iodinated contrast in the bladder of the patient.

  19. Volume study pre and post-implant brachytherapy prostate for establishment of PTV margins; Estudio de volumenes pre y post-implante en braquiterapia de prostata para establecimiento de margenes del PTV

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez Dominguez, M.; Carrasco Herrera, M.; Baeza Trujillo, M.; Herrador Cordoba, M.

    2011-07-01

    Treatment of prostate cancer by permanent implantation of radioactive seeds is now a good alternative to radical surgery or radiotherapy, as it provides a good tumor control while the risk is reduced by a lower complication irradiation of adjacent healthy organs. The large volume change during seed implantation occurs in the prostate of the patient, makes it important to consider margins around the organs of interest both to ensure optimal coverage and minimal tumor irradiation of healthy tissue. Analyze how the volume varies during and after implantation and establish a margin around the prostate to the practice of our hospital are the two objectives of this work.

  20. Estimates of relative doses of {sup 106}Ru/{sup 106}Rh of spherical applicators used in ophthalmic brachytherapy; Estimativas de doses relativas de aplicadores esfericos de {sup 106}Ru/{sup 106}Rh usados em braquiterapia oftalmologica

    Energy Technology Data Exchange (ETDEWEB)

    Paiva, Eduardo de, E-mail: edup2112@gmail.com, E-mail: epaiva@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Div. de Fisica Medica

    2016-11-01

    Spherical ophthalmic applicators containing the beta emitter {sup 106}Ru / {sup 106}Rh are much used in brachytherapy for the treatment of various eye diseases. However, there is great difficulty in dosimetry these sources because of its geometric shape, the short range of the beta particles and the large dose gradient, and because of that calculation methods of dose distributions around these sources take on a great importance. In this work an analytical / numerical method is used to estimate the dose rates for a function of depth for spherical sources containing {sup 106}Ru / {sup 106}Rh. The results of the doses on along the central axis for applicators models CXS, CCX, CCY, CCZ, CCD and CGD and CCC are compared with published values calculated by Monte Carlo simulation and measurement results.

  1. Importance of the neutrons kerma coefficient in the planning of Brachytherapy treatments with Cf-252 sources; Importancia del coeficiente de kerma de neutrones en la planeacion de tratamientos de Braquiterapia con fuentes de Cf-252

    Energy Technology Data Exchange (ETDEWEB)

    Paredes G, L.; Balcazar G, M. [ININ, 52045 Ocoyocac, Estado de Mexico (Mexico); Azorin N, J. [Universidad Autonoma Metropolitana, 09000 Mexico D.F. (Mexico); Francois L, J.L. [UNAM, 04500 Mexico D.F. (Mexico)]. e-mail: lpg@nuclear.inin.mx

    2006-07-01

    The Cf-252 is a fast neutrons emitting radioisotope by spontaneous fission that can be used as sealed source in medicine applications, industry and research. Commercially its offer sources of different sizes, compact and with a fast neutrons emission of the order of 10{sup 6} n/s-{mu}g and an energy spectra that presents respectively maxim and average energy in 2.1 MeV and 0.7 MeV. In medicine new applications are being developed for the treatment of patient with hypoxic and voluminous tumors, where the therapy with photons has not given positive results, as well as for the protocols of therapy treatment by boron neutron capture, where very small sources of Cf-252 will be used with the interstitial brachytherapy technique of high and low dose rate. In this work an analysis of how the small differences that exist in the elementary composition of 4 wicked tumors, 4 ICRU healthy tissues and 3 substitute materials of ICRU tissue used in dosimetry are presented, its generate changes in the neutrons kerma coefficient in function of the energy and consequently in the absorbed dose in the interval of 11 eV to 29 MeV. These differences can produce maximum variations of the neutron kerma coefficients ratio for E{sub n} > 1 keV of the one: 15% tumor/ICRU guest healthy tissue, 12% ICRU tumor/muscle, 12% ICRU healthy tissues ICRU/ICRU muscle, 22% substitutes tissue/tumor and 22% ICRU substitutes tissue/muscle. Also, it was found that the average value of the neutrons kerma coefficient for the 4 wicked tumors is from 6% to 7% smaller that the average value for the soft tissue in the interval energy of interest for therapy with fast neutrons with E{sub n} > 1 MeV. These results have a special importance during the planning process of brachytherapy treatments with sources of {sup 252}Cf, to optimize and to individualize the patients treatments. (Author)

  2. Study of the radiation levels in low dose rate brachytherapy zones of the National Institute of Neoplastic Illnesses; Estudio de los Niveles de Radiacion en Zonas de Braquiterapia de Baja Tasa de Dosis del Instituto Nacional de Enfermedades Neoplasicas

    Energy Technology Data Exchange (ETDEWEB)

    Figueroa J, N.; Mora Y, B. [Instituto Nacional de Enfermedades Neoplasicas, Lima (Peru)]. e-mail: navorf01@yahoo.es

    2006-07-01

    The present study has as objective to evaluate the radiation levels of the Brachytherapy work areas of low dose rate (Gammateque, nurses station and of hospitalization rooms of patients RIC of 4th, 5th Floor-East) and to estimate the effective dose of the occupationally exposed personnel and the public in general. The measurements of the dose rate in these areas, were registered with a radiations monitor Inspector trademark, during a period of 60 days, without altering the routinary work conditions. The more high levels of environmental dose equivalent rate registered in the different work areas its are of 1.41 and 47.78 {mu}Sv/h rooms 1 and 2 in the Gammateque environments, in the hospitalization rooms of the 4th and 5th floor in the point 1 are of 40.77 and 23.67, {mu}Sv/h respectively and in the point 2 are of 129.19 and 39.93, {mu}Sv/h respectively, and in the nurses station of the 4th and 5th floor its are respectively of 7.62 u Sv/h and 0.45 u Sv/h. According to the carried out measurements and the permanency in the work place is possible to estimate the effective dose involved to the occupationally exposed personnel. The personnel that works in Gammateque could be receiving respectively as maximum dose 0.61 mSv/month, and the personnel that works in the nurses station of 13.17 and 0.78 mSv/year in the 4th and 5th floor. These registered differences among the two floors are due to that the 5th floor counts with the shielding systems (screen) contrary to the 4th, another of the factors is the distribution form of the patient beds RIC. We should have present that the radiation levels although in some cases it is very high, however, they are below of the permissible limits according to standards, but it is still possible to reduce even more, the radiation levels in the critical points fulfilling with the ALARA principle. (Author)

  3. Simulation Monte Carlo as a method of verification of the characterization of fountains in ophthalmic brachytherapy; Simulacion Monte Carlo como metodo de verificacion de la caracterizacion de fuentes en braquiterapia oftalmica

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    Ortiz Lora, A.; Miras del Rio, H.; Terron Leon, J. A.

    2013-07-01

    Following the recommendations of the IAEA, and as a further check, they have been Monte Carlo simulation of each one of the plates that are arranged at the Hospital. The objective of the work is the verification of the certificates of calibration and intends to establish criteria of action for its acceptance. (Author)

  4. Verification of the calculation program for brachytherapy planning system of high dose rate (PLATO); Programa de verificacion del calculo para un sistema de planificacion de braquiterapia de alta tasa de dosis (PLATO)

    Energy Technology Data Exchange (ETDEWEB)

    Almansa, J.; Alaman, C.; Perez-Alija, J.; Herrero, C.; Real, R. del; Ososrio, J. L.

    2011-07-01

    In our treatments are performed brachytherapy high dose rate since 2007. The procedures performed include gynecological intracavitary treatment and interstitial. The treatments are performed with a source of Ir-192 activity between 5 and 10 Ci such that small variations in treatment times can cause damage to the patient. In addition the Royal Decree 1566/1998 on Quality Criteria in radiotherapy establishes the need to verify the monitor units or treatment time in radiotherapy and brachytherapy. All this justifies the existence of a redundant system for brachytherapy dose calculation that can reveal any abnormality is present.

  5. Study and parameters survey for iodine-125 source dosimetry to be applied in brachytherapy; Estudo e levantamentos de parametros para dosimetria de fontes de iodo-125 aplicadas em braquiterapia

    Energy Technology Data Exchange (ETDEWEB)

    Moura, Eduardo Santana de

    2011-07-01

    The use of brachytherapy technique with iodine-125 seeds to prostate cancer treatment has been used for decades with good clinical outcomes. To aim the Brazilian population necessities, IPEN-CNEN/SP developed the iodine-125 seed prototype with national technology. The objectives of this work are the development and the study of dosimetric procedures associates with the experimental acquisition of the useful parameters for the iodine-125 dosimetric characterization and to evaluate if the developed procedures, in this work, have the basic conditions to determinate the dosimetric analysis, that are fundamental for clinical procedures. The dosimeters selected for the analysis are the TLD-100 (LiF:Mg,Ti), initially these dosimeters were submitted for two selection steps to choose the dosimeters more reproducible for the dosimetric analysis. The two steps were the selection by the mass of the dosimeters and the reproducibility after four irradiation series in a Cobalt-60 irradiator (CTR-IPEN). Afterwards these steps, the dosimeters were irradiated in linear accelerator with 6 MV energy (Service of Radiotherapy - Hospital Israelita Albert Einstein) to yield the individual calibration factors to each dosimeter. After, the dosimeters were used to the irradiations with iodine-125 seed, 6711 model, (GE-Healthcare). The irradiations and others analysis with iodine-125 seeds yield the useful values for the determination of the parameters suggested by the AAPM (American Association of Physicists in Medicine): constant of dose rate, geometry function, dose radial function and anisotropy function. The results showed good agreement with the values published by the literature, for the same iodine- 125 model, this fact confirms that the realized parameters will be able to be used for the IPEN-CNEN iodine-125 seeds dosimetry and quality control. (author)

  6. Implementation of three-dimensional planning in brachytherapy of high dose rate for gynecology therapies; Implementacao de planejamento tridimensional em braquiterapia de alta taxa de dose para tratamentos ginecologicos

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    Sales, Camila Pessoa de

    2015-09-01

    This work aims to implement the three-dimensional (3D) planning for gynecological brachytherapy treatments. For this purpose, tests of acceptance and commissioning of brachytherapy equipment were performed to establish a quality and periodic assurance program. For this purpose, an important step was searching for a material to be used as a dummy source, since the applicators do not have any specific dummy. In addition, the validation of the use of applicators library was made for reconstruction in computed tomography (CT) and magnetic resonance imaging (MRI). In order to validate 3D planning, comparison of doses in dose assessment points used in bidimensional (2D) plans have been performed with volumetric doses to adjacent organs to the tumor. Finally, a protocol was established for 3D brachytherapy planning alternately using magnetic resonance image (MRI) and CT images, making evaluation of the dose in the tumor through the recording of MR and CT images. It was not possible to find a suitable material that could be used as dummy in MRI. However, the acquisition of the license's library for the applicators made possible the 3D planning based on MRI. No correlation was found between volumetric and specific doses analyzed, showing the importance of the implementation of 3D planning. The average ratio between D{sub 2cc} and ICRU{sub Bladder} dose was 1,74, 22% higher than the ratio found by others authors. For the rectum, D{sub 2cc} was less than dose point for 60% of fractions; the average difference was 12,5%. The average ratio between D{sub 2cc} and point dose rectum, 0,85, is equivalent to the value showed by Kim et al, 0,91. The D{sub 2cc} for sigmoid was 69% higher than point dose used, unless it was not possible compare this value, since the sigmoid point used in the 2D procedures is not used in others institutes. Relative dose in 2 cc of sigmoid was 57% of the prescription dose, the same value was found by in literature. This work enabled the implementation of a viable brachytherapy 3D protocol planning, using MRI for the first fraction of the treatment and CT images for the subsequent fractions. (author)

  7. Preparation and determination of kerma for Iridium 192 sources of low dose rate for brachytherapy; Preparacion y determinacion del kerma de fuentes de iridio-192 de baja tasa de dosis para braquiterapia

    Energy Technology Data Exchange (ETDEWEB)

    Tendilla, J.I.; Tovar M, V.; Mitsoura, E.; Aguilar H, F.; Alanis M, J. [Instituto Nacional de Investigaciones Nucleares, C.P. 52045-1, Salazar, Esrado de Mexico, D.F. (Mexico)

    2000-07-01

    The practice of Brachytherapy with Iridium-192 sources of low dose rate (0.4 - 0.8 Gy/h) is a technique used in the treatment of diverse illnesses. in this work the preparation, quality control and calibration are presented in terms of kerma in air of Iridium-192 using as target these recycled Iridium-Platinum wires. The targets were obtained as decayed sources of different radio therapeutical centers in the country and they were characterized by Scanning electron microscopy in order to determine their chemical composition. Subsequently it was developed an experimental design to establish the effect of neutron flux, geometrical array and irradiation time over the activity and percentage of the sources homogeneity. The homogeneity was determined by auto radiography and by Gamma spectroscopy. Once the optimal irradiation conditions were established, it is determined the apparent activity and kerma in air using a well type ionization chamber with traceability to a primary laboratory. Iridium-192 sources were obtained with an average homogeneity 96 %, apparent activity 282.129 {+-} 0.531 M Bq and kerma in air 0.03200 {+-} 0.00006 m Gy m/h A. (Author)

  8. Methodology, results and experience of independent brachytherapy plan verifications based on DICOM standard; Implementacion, resultados y experiencia de una verificacion independiente de tratamientos de braquiterapia basada en el estandar DICOM

    Energy Technology Data Exchange (ETDEWEB)

    Ferrando Sanchez, A.; Pardo Perez, E.; Castro Novals, J.; Casa de Julian, M. A. de la; Cabello Murillo, E.; Diaz Fuentes, R.; Molina Lopez, M. Y.

    2013-09-01

    The use of a high dose rate source together with an afterloading treatment delivery in brachytherapy plans allows for dose modulation minimizing dose to staff. An independent verification of the exported data to the treatment station is required by local regulations (being also a widely accepted recommendation on the international literature). We have developed a methodology under home brew code to import DICOM treatment data onto an Excel spreadsheet that is able to calculate dose on given reference points using the TG-43 formalism of the AAPM3-5. It employs analytic fits of anisotropy factor and radial dose function for different sources. The end point implementations we present here allow merging in one step an independent verification and a treatment printout. The use of DICOM standard makes our code versatile and provides greater compatibility with respect to current treatment planning systems. (Author)

  9. Viability of neutron brachytherapy technique using Cf{sup 252} for tumors of salivary glands therapy; Viabilidade da tecnica de braquiterapia de neutrons por Cf{sup 252} para tratamento de tumores de glandulas salivares

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Lidia M.; Campos, Tarcisio P.R. [Minas Gerais Univ., Belo Horizonte, MG (Brazil). Dept. de Engenharia Nuclear]. E-mail: campos@nuclear.ufmg.br; lidia@nuclear.ufmg.br

    2000-07-01

    Gland salivary tumors, although uncommon, present significant characteristics such as distant metastasis, recurrence and average survive of five year for treated patients. Those tumors presents low response to a conventional radiotherapy, photon and electron therapy; thus, this modality is associated with surgery. Fast neutron therapy has been presented better results in controlling the local tumor in comparison with conventional radiotherapy. Brachytherapy with Cf-252 presents an alternative treatment for tumors. Those radiotherapy technique are discussed and analyzed. (author)

  10. Molecular cloning and functional identification of a cDNA encoding 4-hydroxy-3-methylbut-2-enyl diphosphate reductase from Tripterygium wilfordii

    Directory of Open Access Journals (Sweden)

    Qiqing Cheng

    2017-03-01

    Full Text Available The 4-hydroxy-3-methylbut-2-enyl diphosphate reductase (HDR is the last step key enzyme of the methylerythritol phosphate (MEP pathway, synthesizing isopentenyl diphosphate and its allyl isomer dimethylallyl diphosphate, which is important for regulation of isoprenoid biosynthesis. Here the full-length cDNA of HDR, designated TwHDR (GenBank Accession No. KJ933412.1, was isolated from Tripterygium wilfordii for the first time. TwHDR has an open reading frame (ORF of 1386 bp encoding 461 amino acids. TwHDR exhibits high homology with HDRs of other plants, with an N-terminal conserved domain and three conserved cysteine residues. TwHDR cDNA was cloned into an expression vector and transformed into an Escherichia coli hdr mutant. Since loss-of-function E.coli hdr mutant is lethal, the result showed that transformation of TwHDR cDNA rescued the E.coli hdr mutant. This complementation assay suggests that the TwHDR cDNA encodes a functional HDR enzyme. The expression of TwHDR was induced by methyl-jasmonate (MJ in T. wilfordii suspension cells. The expression of TwHDR reached the highest level after 1 h of MJ treatment. These results indicate that we have identified a functional TwHDR enzyme, which may play a pivotal role in the biosynthesis of diterpenoid triptolide in T. wilfordii.

  11. Integrated interpretation of AE clusters and fracture system in Hijiori HDR artificial reservoir; Hijiori koon gantai jinko choryuso no AE cluster to kiretsu system ni kansuru togoteki kaishaku

    Energy Technology Data Exchange (ETDEWEB)

    Tezuka, K. [Japan Petroleum Exploration Corp., Tokyo (Japan); Niitsuma, H. [Tohoku University, Sendai (Japan)

    1997-05-27

    With regard to a fracture system in the Hijiori hot dry rock artificial reservoir, an attempt was made on an interpretation which integrates different data. Major factors that characterize development and performance of an artificial reservoir are composed of a fracture system in rocks, which acts as circulating water paths, a heat exchange face and a reservoir space. The system relates not only with crack density distribution, but also with cracks activated by water pressure fracturing, cracks generating acoustic emission (AE), and cracks working as major flow paths, all of which are characterized by having respective behaviors and roles. Characteristics are shown on AE cluster distribution, crack distribution, production zone and estimated stress fields. Mutual relationship among these elements was discussed based on the Coulomb`s theory. The most important paths are characterized by distribution of slippery cracks. Directions and appearance frequencies of the slippery cracks affect strongly directionality of the paths, which are governed by distribution of the cracks (weak face) and stress field. Among the slippery cracks, cracks that generate AE are cracks that release large energy when a slip occurs. Evaluation on slippery crack distribution is important. 7 refs., 8 figs.

  12. Remediación in situ de agua contaminada con diesel por oxidación con peróxido de hdrógeno

    Directory of Open Access Journals (Sweden)

    Cardona Gallo Santiago Alonso

    2011-11-01

    Full Text Available Las grandes cantidades de hidrocarburos que se manejan en el mundo y en México, generan derrames de crudo y sus derivados, deteriorando en gran medida el medioambiente y especialmente las fuentes de suministro de agua subterránea. En México, el 27% del agua potable proviene de los acuíferos. Lo anterior permite plantear la necesidad de desarrollar sistemas de tratamiento viables que pueden reducir la contaminación rápida y económicamente de los acuíferos. Este trabajo presenta la oxidación del diesel combustible en solución con un agente oxidante, peróxido de hidrógeno; grado industrial al 50%. Se utilizó el H2O2, porque es un agente oxidante fuerte muy conocido, de fácil manejo, de bajo costo y una solubilidad mayor en el agua que el oxígeno molecular. Se tuvo una concentración inicial de diesel en solución de 45.000 mg/L, bajo agitación horizontal continua en un sistema en serie durante 114 horas. Las muestras fueron tomadas periódicamente. Al final de las 114 horas, la concentraci��n del hidrocarburo descendió hasta 24.000 mg/L, obteniendo una velocidad de la reacción de 0,0047 h-1 (0,1128 d-1. El estudio fue llevado a cabo sin catalizador. El efluente presentó un intervalo de pH entre 6,5 y 7,5. Con los resultados previos fueron diseñadas las columnas y operadas intermitentemente, y se comparó con columnas sin adición de peróxido de hidrógeno. La eficiencia del sistema y el bajo costo pueden ser aplicados en diferentes sistemas para el tratamiento de diesel en barreras reactivas permeables, zonas reactivas o aguas subterráneas.

  13. Comparison of Oncentra® Brachy IPSA and graphical optimisation techniques: a case study of HDR brachytherapy head and neck and prostate plans

    Energy Technology Data Exchange (ETDEWEB)

    Jameson, Michael G, E-mail: michael.jameson@sswahs.nsw.gov.au [Liverpool and Macarthur Cancer Therapy Centres, Liverpool, New South Wales (Australia); Centre for Medical Radiation Physics, University of Wollongong, Wollongong, New South Wales (Australia); Ingham Institute of Applied Medical Research, Liverpool, New South Wales (Australia); Ohanessian, Lucy [Liverpool and Macarthur Cancer Therapy Centres, Liverpool, New South Wales (Australia); Batumalai, Vikneswary [Liverpool and Macarthur Cancer Therapy Centres, Liverpool, New South Wales (Australia); Ingham Institute of Applied Medical Research, Liverpool, New South Wales (Australia); South Western Sydney Clinical School, School of Medicine, University of New South Wales (Australia); Patel, Virendra [Liverpool and Macarthur Cancer Therapy Centres, Liverpool, New South Wales (Australia); Holloway, Lois C [Liverpool and Macarthur Cancer Therapy Centres, Liverpool, New South Wales (Australia); Centre for Medical Radiation Physics, University of Wollongong, Wollongong, New South Wales (Australia); Ingham Institute of Applied Medical Research, Liverpool, New South Wales (Australia); South Western Sydney Clinical School, School of Medicine, University of New South Wales (Australia); Institute of Medical Physics, School of Physics, University of Sydney, Sydney, New South Wales (Australia)

    2015-06-15

    There are a number of different dwell positions and time optimisation options available in the Oncentra® Brachy (Elekta Brachytherapy Solutions, Veenendaal, The Netherlands) brachytherapy treatment planning system. The purpose of this case study was to compare graphical (GRO) and inverse planning by simulated annealing (IPSA) optimisation techniques for interstitial head and neck (HN) and prostate plans considering dosimetry, modelled radiobiology outcome and planning time. Four retrospective brachytherapy patients were chosen for this study, two recurrent HN and two prostatic boosts. Manual GRO and IPSA plans were generated for each patient. Plans were compared using dose–volume histograms (DVH) and dose coverage metrics including; conformity index (CI), homogeneity index (HI) and conformity number (CN). Logit and relative seriality models were used to calculate tumour control probability (TCP) and normal tissue complication probability (NTCP). Approximate planning time was also recorded. There was no significant difference between GRO and IPSA in terms of dose metrics with mean CI of 1.30 and 1.57 (P > 0.05) respectively. IPSA achieved an average HN TCP of 0.32 versus 0.12 for GRO while for prostate there was no significant difference. Mean GRO planning times were greater than 75 min while average IPSA planning times were less than 10 min. Planning times for IPSA were greatly reduced compared to GRO and plans were dosimetrically similar. For this reason, IPSA makes for a useful planning tool in HN and prostate brachytherapy.

  14. Comparison of Oncentra® Brachy IPSA and graphical optimisation techniques: a case study of HDR brachytherapy head and neck and prostate plans.

    Science.gov (United States)

    Jameson, Michael G; Ohanessian, Lucy; Batumalai, Vikneswary; Patel, Virendra; Holloway, Lois C

    2015-06-01

    There are a number of different dwell positions and time optimisation options available in the Oncentra® Brachy (Elekta Brachytherapy Solutions, Veenendaal, The Netherlands) brachytherapy treatment planning system. The purpose of this case study was to compare graphical (GRO) and inverse planning by simulated annealing (IPSA) optimisation techniques for interstitial head and neck (HN) and prostate plans considering dosimetry, modelled radiobiology outcome and planning time. Four retrospective brachytherapy patients were chosen for this study, two recurrent HN and two prostatic boosts. Manual GRO and IPSA plans were generated for each patient. Plans were compared using dose-volume histograms (DVH) and dose coverage metrics including; conformity index (CI), homogeneity index (HI) and conformity number (CN). Logit and relative seriality models were used to calculate tumour control probability (TCP) and normal tissue complication probability (NTCP). Approximate planning time was also recorded. There was no significant difference between GRO and IPSA in terms of dose metrics with mean CI of 1.30 and 1.57 (P > 0.05) respectively. IPSA achieved an average HN TCP of 0.32 versus 0.12 for GRO while for prostate there was no significant difference. Mean GRO planning times were greater than 75 min while average IPSA planning times were less than 10 min. Planning times for IPSA were greatly reduced compared to GRO and plans were dosimetrically similar. For this reason, IPSA makes for a useful planning tool in HN and prostate brachytherapy.

  15. Targeting Homology-Directed Recombinational Repair (HDR) of Chromosomal Breaks to Sensitize Prostate Cancer Cells to Poly (ADP-Ribose) Polymerase (PARP) Inhibition

    Science.gov (United States)

    2013-08-01

    Dawant, BM. Comparison of manual and automatic segmentation methods for brain structures in the presence of space-occupying lesions : a multi-expert...DS, Dawant, BM. Segmentation editing improves efficiency while reducing inter-expert variation and maintaining accuracy for normal brain tissues in...can enhance tumor susceptibility to DNA damage by novel combinations of targeted agents. Additionally, we aim to protect normal brain by augmenting

  16. Body mass index versus bladder and rectal doses using 2D planning for patients with carcinoma of the cervix undergoing HDR brachytherapy

    Directory of Open Access Journals (Sweden)

    Anil Kumar Talluri

    2016-06-01

    Full Text Available Purpose: To assess bladder and rectum doses in relation to body mass index of patients undergoing high dose rate brachytherapy for the treatment of carcinoma of the cervix.Methods: The cohort consists of fifty subjects with carcinoma of the uterine cervix presented with grade II and III. Patient’s height and weight was measured before the insertion of applicator in situ. Body mass index (BMI of the patient was calculated in accordance to World Health Organization definition (weight in Kg/ height in m2. Adequacy of position and orientation of the applicator was confirmed with the help of orthogonal X-ray images and the same were transferred to the treatment planning system (TPS to generate treatment plan. Prescription doses were optimized to Point A and to reference lines placed at 0.5 cm apart from the surface of ovoids. The following dose reference points were identified on orthogonal x-ray images for analysis using the rectal marker and Foleys bulb inflated with radio opaque dye Rectal points at the level of femoral heads (RL and pubis symphysis (RLP, Anorectum Junction (AR Jn point and Rectosigmoid (RS point and Bladder point (BL. Pearson regression analysis was used to analyze data from TPS.Results: The mean BMI was 22.7 kg/m2 and average age was 49.9 years. Analysis showed that RL point dose and BMI were inversely correlated with a coefficient -0.45 (p = 0.001. The trend continued along the rectal tube in cranio-caudal direction, as RLP and AR Jn points showed inversion co-efficiency with increase in BMI,-0.48 (p < 0.01 and -0.51 (p < 0.01 respectively. Bladder point showed weak positive correlation to BMI, 0.12 (p = 0.38.Conclusion: Significant rectal dose reduction is observed with increase in BMI. Bladder dose did not show statistically significant correlation with BMI. Based on the findings, BMI constitutes a confounding factor in the treatment of carcinoma of cervix.

  17. Evaluation of deformable image registration between external beam radiotherapy and HDR brachytherapy for cervical cancer with a 3D-printed deformable pelvis phantom.

    Science.gov (United States)

    Kadoya, Noriyuki; Miyasaka, Yuya; Nakajima, Yujiro; Kuroda, Yoshihiro; Ito, Kengo; Chiba, Mizuki; Sato, Kiyokazu; Dobashi, Suguru; Yamamoto, Takaya; Takahashi, Noriyoshi; Kubozono, Masaki; Takeda, Ken; Jingu, Keiichi

    2017-04-01

    In this study, we developed a 3D-printed deformable pelvis phantom for evaluating spatial DIR accuracy. We then evaluated the spatial DIR accuracies of various DIR settings for cervical cancer. A deformable female pelvis phantom was created based on patient CT data using 3D printing. To create the deformable uterus phantom, we first 3D printed both a model of uterus and a model of the internal cavities of the vagina and uterus. We then made a mold using the 3D printed uterus phantom. Finally, urethane was poured into the mold with the model of the internal cavities in place, creating the deformable uterus phantom with a cavity into which an applicator could be inserted. To create the deformable bladder phantom, we first 3D printed models of the bladder and of the same bladder scaled down by 2 mm. We then made a mold using the larger bladder model. Finally, silicone was poured into the mold with the smaller bladder model in place to create the deformable bladder phantom with a wall thickness of 2 mm. To emulate the anatomical bladder, water was poured into the created bladder. We acquired phantom image without applicator for EBRT. Then, we inserted the applicator into the phantom to simulate BT. In this situation, we scanned the phantom again to obtain the phantom image for BT. We performed DIR using the two phantom images in two cases: Case A, with full bladder (170 ml) in both EBRT and BT images; and Case B with full bladder in the BT image and half-full bladder (100 ml) in the EBRT image. DIR was evaluated using Dice similarity coefficients (DSCs) and 31 landmarks for the uterus and 25 landmarks for the bladder. A hybrid intensity and structure DIR algorithm implemented in RayStation with four DIR settings was evaluated. On visual inspection, reasonable agreement in shape of the uterus between the phantom and patient CT images was observed for both EBRT and BT, although some regional disagreements in shape of the bladder and rectum were apparent. The created phantom could reproduce the actual patient's uterus deformation by the applicator. For both Case A and B, large variation was seen in landmark error among the four DIR parameters. In addition, although DSCs were comparable, moderate differences in landmark error existed between the two different DIR parameters selected from the four DIR parameters (i.e., DSC = 0.96, landmark error = 13.2 ± 5.7 mm vs. DSC = 0.97, landmark error = 9.7 ± 4.0 mm). This result suggests that landmark error evaluation might thus be more effective than DSC for evaluating DIR accuracy. Our developed phantom enabled the evaluation of spatial DIR accuracy for the female pelvic region for the first time. Although the DSCs are high, the spatial errors can still be significant and our developed phantom facilitates their quantification. Our results showed that optimization is needed to identify suitable DIR settings. For determining suitable DIR settings, our method of evaluating spatial DIR accuracy using the 3D-printed phantom may prove helpful. © 2017 American Association of Physicists in Medicine.

  18. A study on the accuracy of source position in HDR brachytherapy according to the curvature of universal application transfer tube and applicator type

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Hyeon Kyung; Lee, Sang Kyoo; Kim, Joo Ho; Cho, Jeong Hee [Dept. of Radiation Oncology, Yonsei Cancer Center, Seoul (Korea, Republic of)

    2015-12-15

    The goal of this study was to verify and analyze the source position according to the curvature of the universal applicator and 4 different angle applicators when using RALS(Remote After Loading System). An interval of 1 cm and 15 second dwell times in each source position were applied for plan. To verify the accuracy of source position, we narrowed the distance between MultiSource container and GAFCHROMIC? EBT3 film by 5 cm, 10 cm, 20 cm so that the universal applicator transfer tube had some curvature. Also 4 applicators(Intrauterine tube: 0° , 15°, 30° , Ovoid tube: 65° ) were used in the same condition. The differences between desired and actual source position were measured by using Image J. In case of using 4 different angles of applicator with the straight universal applicator transfer tube, the average error was the lowest for 0°applicator, greatest for 65°applicator. However, All average errors were within ±2 mm recommended in TG-56. When MultiSource container was moved 5 cm, 10 cm, 20 cm towards the EBT3 film, the average errors were beyond ±2 mm. The first dwell position was relatively located in accuracy, while the second and third dwells were displaced by an increasing magnitude with increasing curvature of the transfer tube. Furthermore, with increasing the angle of applicators, the error of all other dwell positioning was increased. The results of this study showed that both the curvature of universal applicator transfer tube and the angle of applicators affect the source dwell position. It is recommended that using straight universal applicator transfer tubes is followed in all cases, in order to avoid deviations in the delivered source dwell position. Also, It is advisable to verify the actual dwell position, using video camera quality control tool prior to all treatments.

  19. SU-F-P-61: Does It Matter Not to Use Optimization Points at the Apex for Vaginal Cylinder HDR Brachytherapy Planning?

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Y [University Of Iowa, College of Medicine, Iowa City, IN (United States)

    2016-06-15

    Purpose: To test the impact of the use of apex optimization points for new vaginal cylinder (VC) applicators. Methods: New “ClickFit” single channel VC applicators (Varian) that have a different top thicknesses but the same diameters as the old VC applicators (2.3 cm diameter, 2.6 cm, 3.0 cm, and 3.5 cm) were compared using phantom studies. Old VC applicator plans without apex optimization points were also compared to the plans with the optimization points. The apex doses were monitored at 5 mm depth doses (8 points) where a prescription dose (Rx) of 6Gy was prescribed. VC surface doses (8 points) were also analyzed. Results: The new VC applicator plans without apex optimization points presented significantly lower 5mm depth doses than Rx (on average −31 ± 7%, p <0.00001) due to their thicker VC tops (3.4 ± 1.1 mm thicker with the range of 1.2 to 4.4 mm) than the old VC applicators. Old VC applicator plans also showed a statistically significant reduction (p <0.00001) due to Ir-192 source anisotropic effect at the apex region but the % reduction over Rx was only −7 ± 9%. However, by adding apex optimization points to the new VC applicator plans, the plans improved 5 mm depth doses (−7 ± 9% over Rx) that were not statistically different from old VC plans (p = 0.923), along with apex VC surface doses (−22 ± 10% over old VC versus −46 ± 7% without using apex optimization points). Conclusion: The use of apex optimization points are important in order to avoid significant additional cold doses (−24 ± 2%) at the prescription depth (5 mm) of apex, especially for the new VC applicators that have thicker tops.

  20. Pořizování HDR snímků na mobilních zařízeních

    OpenAIRE

    Padyšák, Michal

    2017-01-01

    Tato bakalářská práce se věnuje problematice digitální fotografie s vysokým dynamickým rozsahem. Řešení této problematiky je provedeno složením několika snímků stejné scény s různou expozicí do jednoho snímku s vysokým dynamickým rozsahem. Metoda je implementována jako aplikace pro operační systém Android a pořízený snímek je schopna zobrazit na svém displeji. This bachelor thesis deals with high dynamic range in digital photography. This problem is solved by composing multiple images with...

  1. Substantial advantage of CT-planned HDR brachytherapy for cervical cancer patients compared to a historical series with regard to local control and toxicity?; Substantieller Vorteil durch CT-geplante HDR-Brachytherapie bei Zervixkarzinompatientinnen im Vergleich zu historischen Serien bezueglich lokaler Kontrolle und Toxizitaet

    Energy Technology Data Exchange (ETDEWEB)

    Marnitz, Simone [Klinik fuer Strahlentherapie der Uniklinik Koeln, Medizinische Fakultaet der Universitaet zu Koeln, CyberKnife Centrum, Koeln (Germany)

    2017-03-15

    The primary radiochemotherapy is the standard treatment for patients with nodal positive and/or locally advanced cervical carcinoma. The therapy consists of percutaneous radiotherapy, simultaneous chemotherapy with cisplatin and an intracervical brachytherapy. The application of highly standardized brachytherapy based on NMR imaging allowed an improved local contol and a considerable reduction of toxicity.

  2. A feasibility study of applying thermal imaging to assist quality assurance of high-dose rate brachytherapy

    Directory of Open Access Journals (Sweden)

    Xiaofeng Zhu

    2017-01-01

    Conclusion: Thermal imaging could be a feasible tool to visualize HDR source dwell positions and verify source integrity. Potentially, patient safety and treatment quality may be improved by integrating thermal measurements into HDR QA procedures.

  3. Verification and analysis of the positioning of a source of brachytherapy high dose within an applicator gynecological interstitial fletcher Utrecht TC/RM; Verificacion y analysis del posicionamiento de una fuente de braquiterapia de alta tasa de dosis dentro de un aplicador ginecologico fletcher intersticial UTRECHT TC/RM

    Energy Technology Data Exchange (ETDEWEB)

    Panedo Cobos, J. M.; Garcia castejon, M. A.; Huertas Martinez, C.; Gomez-Tejedor Alonso, S.; Rincon Perez, M.; Luna Tirado, J.; Perez Casas, A. M.

    2013-07-01

    Applicators are guides that circulate and are located within the patient brachytherapy sources. Applicators can suffer mechanical deformations due to processes of sterilization or shock, which may result in that the source do not place within these very precise and coincides with the planned. In these cases the planned treatment deviate actually managed. The object of this study is to verify that the position of the source into the dispenser coincides with the planned position, with a procedure that is described. (Author)

  4. Influence of radioactive sources discretization in the Monte Carlo computational simulations of brachytherapy procedures: a case study on the procedures for treatment of prostate cancer; Influencia da discretizacao das fontes radioativas nas simulacoes computacionais Monte Carlo de procedimentos de braquiterapia: um estudo de caso sobre os procedimentos para tratamento do cancer de prostata

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, Antonio Konrado de Santana; Vieira, Jose Wilson [Instituto Federal de Educacao, Ciencia e Tecnologia (IFPE), Recife, PE (Brazil); Costa, Kleber Souza Silva [Faculdade Integrada de Pernambuco (FACIPE), Recife, PE (Brazil); Lima, Fernando Roberto de Andrade, E-mail: falima@cnen.gov.b [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

    2011-07-01

    Radiotherapy computational simulation procedures using Monte Carlo (MC) methods have shown to be increasingly important to the improvement of cancer fighting strategies. One of the biases in this practice is the discretization of the radioactive source in brachytherapy simulations, which often do not match with a real situation. This study had the aim to identify and to measure the influence of radioactive sources discretization in brachytherapy MC simulations when compared to those that do not present discretization, using prostate brachytherapy with Iodine-125 radionuclide as model. Simulations were carried out with 108 events with both types of sources to compare them using EGSnrc code associated to MASH phantom in orthostatic and supine positions with some anatomic adaptations. Significant alterations were found, especially regarding bladder, rectum and the prostate itself. It can be concluded that there is a need to discretized sources in brachytherapy simulations to ensure its representativeness. (author)

  5. Study and methodology development for quality control in the production process of iodine-125 radioactive sealed sources applied to brachytherapy; Estudo e desenvolvimento de metodologia para controle de qualidade em processo de producao de fontes seladas de iodo-125 para aplicacao em braquiterapia

    Energy Technology Data Exchange (ETDEWEB)

    Moura, Joao Augusto

    2009-07-01

    Today cancer is the second cause of death by disease in several countries, including Brazil. Excluding skin cancer, prostate cancer is the most incident in the population. Prostate tumor can be treated by several ways, including brachytherapy, which consists in introducing sealed radioactive sources (Iodine - 125 seeds) inside the tumor. The target region of treatment receives a high radiation dose, but healthy neighbor tissues receive a significantly reduced radiation dose. The seed is made of a welding sealed titanium capsule, 0.8 mm external diameter and 4.5 mm length, enclosing a 0.5 mm diameter silver wire with Iodine-125 adsorbed. After welded, the seeds have to be submitted to a leak test to prevent any radioactive material release. The aims of this work were: (a) the study of the different leakage test methods applied to radioactive seeds and recommended by the ISO 997820, (b) the choice of the appropriate method and (c) the flowchart determination of the process to be used during the seeds production. The essays exceeded the standards with the use of ultra-sound during immersion and the corresponding benefits to leakage detection. Best results were obtained with the immersion in distilled water at 20 degree C for 24 hours and distilled water at 70 degree C for 30 minutes. These methods will be used during seed production. The process flowchart has all the phases of the leakage tests according to the sequence determined in the experiments. (author)

  6. Complementary method of analyzing the quality of the implant I-125 seeds for prostate brachytherapy using ultrasound imaging post-implant; Metodo complementario de analisis de la calidad del implante de semillas de I-125 para braquiterapia de prostata mediante la adquisicion de imagenes ecograficas post-implante

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez Dominguez, M.; Carrasco Herrera, M.; Baeza Trujillo, M.; Herrador Cordoba, M.

    2011-07-01

    In this paper we propose a complementary method based on Longitudinal mode ultrasound images acquired the same day of surgery, at the end of the implant. This option will allow us to evaluate the dosimetry end of treatment with the patient in the same position he was planning and to the rectum and bladder just as full. This will permit the identification of bodies and the seeds of interest more easily and will have a reference with which to compare one month later, when the CT images can also detect whether there has been some migration.

  7. Measuring the absorbed dose in critical organs during low rate dose brachytherapy with {sup 137} Cs using thermoluminescent dosemeters; Medicion de la dosis absorbida en organos criticos durante braquiterapia de baja tasa de dosis con {sup 137} Cs usando dosimetros termoluminiscentes

    Energy Technology Data Exchange (ETDEWEB)

    Torres, A. [UAEM, Fac. de Medicina, 50180 Toluca, Estado de Mexico (Mexico); Gonzalez, P.R. [ININ, A.P. 18-1027, 11801 Mexico D.F. (Mexico); Furetta, C.; Azorin, J. [UAM-I, 09340 Mexico D.F. (Mexico); Andres, U.; Mendez, G. [Centro Estatal de Cancerologia de Tabasco, A. Gregorio Mendez No. 2838, Col. Atasta, 86100 Villahermosa, Tabasco (Mexico)

    2003-07-01

    Intracavitary Brachytherapy is one of the most used methods for the treatment of the cervical-uterine cancer. This treatment consists in the insertion of low rate dose {sup 137}Cs sources into the patient. The most used system for the treatment dose planning is that of Manchester. This planning is based on sources, which are considered fixed during the treatment. However, the experience has shown that, during the treatment, the sources could be displaced from its initial position, changing the dose from that previously prescribed. For this reason, it is necessary to make measurements of the absorbed dose to the surrounding organs (mainly bladder and rectum). This paper presents the results of measuring the absorbed dose using home-made LiF: Mg, Cu, P + Ptfe thermoluminescent dosimeters (TLD). Measurements were carried out in-vivo during 20 minutes at the beginning and at the end of the treatments. Results showed that the absorbed dose to the critical organs vary significantly due to the movement of the patient during the treatment. (Author)

  8. Dosimetric results in implant and post-implant and low rate in brachytherapy prostate cancer with loose seeds and attached; Resultados dosimetricos en el implante y post-impante en braquiterapia de baja tasa en cancer de prostata con semillas sueltas y unidas

    Energy Technology Data Exchange (ETDEWEB)

    Juan-Senabre, X. J.; Albert Antequera, M.; Lopez-Tarjuelo, J.; Santos Serra, A.; Perez-Mestre, M.; Sanchez Iglesias, A. L.; Conde Moreno, A. J.; Gonzalez Vidal, V.; Beltran Persiva, J.; Muelas Soria, R.; Ferrer Albiach, C.

    2015-07-01

    The objective is determine differences dosimetry statistics on the dosimetry of the implant and post-implant in brachytherapy of low rate with implants permanent in prostate using seed of 125-I loose and attached Both in lives and in the post-prostatic plans dosimetric coverage is good and restrictions in urethra and rectum for both groups of patients are met. Not migrating with joined is evident, as well as better dosimetric homogeneity. (Author)

  9. Evaluation of the response of polymeric gel modified MAGIC-f using a clinical brachytherapy source and Monte Carlo simulation with package PENELOPE; Avaliacao da resposta do gel polimerico MAGIC-f modificado utilizando uma fonte clinica de braquiterapia e simulacao Monte Carlo com o pacote PENELOPE

    Energy Technology Data Exchange (ETDEWEB)

    Quevedo, Ana Luiza; Nicolucci, Patricia [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Filosofia Ciencias e Letras. Dept. de Fisica; Borges, Leandro F. [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Hospital das Clinicas. Setor de Radioterapia

    2016-07-01

    In this work a comparison of experimental and simulated relative doses of a clinical brachytherapy source was performed. A 5 x 5 x 7 cm{sup 3} phantom with a modified MAGIC-f gel was irradiated using a clinical {sup 192}Ir source and read using Magnetic Resonance Imaging. The Monte Carlo simulation package PENELOPE was used to simulate the dose distributions of the same radiation source. The dose distributions were obtained in two planes perpendicular to the source: one passing through the source's center and the other at 0.5 cm away from the source's center. The higher differences found between experimental and computational distributions were 12.5% at a point 0.62 cm from the source for the central plane and 8.6% at 1.3 cm from the source to the plane 0.5 cm away from the source's center. Considering the high dose gradient of these dose distributions, the results obtained show that the modified MAGIC-f gel is promising for brachytherapy dosimetry. (author)

  10. Impact on safety and radiation protection standard operating procedures and internal emergency plans in case of high dose rate brachytherapy; Incidencia en la seguridad y proteccion radiologica de procedimientos normalizados y planes de emergencia interiores en caso de la braquiterapia de alta tasa

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez Dominguez, M.; Rodriguez Alarcon, C.; Baeza Trujillo, M.; Haro Madero, G.; Herrador Cordoba, M.

    2011-07-01

    Emergency situations are the result of unplanned events where there may be (accidents) or not(incidents)likely to exceed the dose limits. In this regard, it is essential to define a set of actions to perform in the event that increases the risk radiological emergency predictable. We analyze here the case of a unit of high-rate brachytherapy.

  11. Dose calculation in eye brachytherapy with Ir-192 threads using the Sievert integral and corrected by attenuation and scattering with the Meisberg polynomials; Calculo de dosis en braquiterapia ocular con hilos de Ir-192 utilizando la integral de Sievert y cooregida por atenuacion y dispersion con los polinomios de Meisberg

    Energy Technology Data Exchange (ETDEWEB)

    Vivanco, M.G. Bernui de; Cardenas R, A. [Instituto Nacional de Enfermedades Neoplasicas, Universidad Nacional de Ingenieria, Av. Angamos No. 2520, Surquillo, Lima (Peru)]. e-mail: gisellebdv@hotmail.com

    2006-07-01

    The ocular brachytherapy many times unique alternative to conserve the visual organ in patients of ocular cancer, one comes carrying out in the National Institute of Neoplastic Illnesses (INEN) using threads of Iridium 192; those which, they are placed in radial form on the interior surface of a spherical cap of gold of 18 K; the cap remains in the eye until reaching the prescribed dose by the doctor. The main objective of this work is to be able to calculate in a correct and practical way the one time that the treatment of ocular brachytherapy should last to reach the dose prescribed by the doctor. To reach this objective I use the Sievert integral corrected by attenuation effects and scattering (Meisberg polynomials); calculating it by the Simpson method. In the calculations by means of the Sievert integral doesn't take into account the scattering produced by the gold cap neither the variation of the constant of frequency of exposure with the distance. The calculations by means of Sievert integral are compared with those obtained using the Monte Carlo Penelope simulation code, where it is observed that they agree at distances of the surface of the cap greater or equal to 2mm. (Author)

  12. Evaluation of the response of modified MAGIC-f polymeric gel using a clinical brachytherapy source and Monte Carlo simulation with package PENELOPE; Avaliacao da resposta do gel polimerico MAGIC-f modificado utilizando uma fonte clinica de braquiterapia e simulacao Monte Carlo com o pacote PENELOPE

    Energy Technology Data Exchange (ETDEWEB)

    Quevedo, Ana Luiza; Nicolucci, Patricia, E-mail: anaquevedo@usp.br [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Dept. de Fisica; Borges, Leandro F. [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Setor de Radioterapia

    2016-07-01

    A comparison of experimental and simulated relative doses of a clinical brachytherapy source was performed. A 5 x 5 x 7 cm{sup 3} phantom with a modified MAGIC-f gel was irradiated using a clinical {sup 192}Ir source, Varian, model GammaMed Plus. The phantom was irradiated with 7,5 Gy, commonly used in gynecological treatments. The dose distributions readings were performed 24h after irradiation using Magnetic Resonance Imaging, weighted in T2, with repetition time of 6000 ms, echo-time of 15 ms, 16 echos and 0.40 mm pixel size. The same brachytherapy source was modeled in the Monte Carlo package PENELOPE to obtain dose distributions. The energy cutoff for electrons, photons and positrons was 100 keV, the primary particles condensation parameters remained the same at 0.3. The dose distributions were obtained in two planes perpendicular to the source: one passing through the source’s center and the other at 0.5 cm away from the source’s center in direction of the top of encapsulation. A comparison of the experimental results using the polymeric gel to the computational results showed maximum differences of 12.5%, at 0.62 cm from the source for the central plane, and 6.4% at 0.5 cm from the source for the superior plane. Considering the high dose gradient of these clinical brachytherapy sources, the results obtained in these work show that MAGIC-f gel with modified formulation, is promising for dosimetry in brachytherapy. (author)

  13. Radiological protection on interstitial brachytherapy and dose determination and exposure rate of an Ir-192 source through the MCNP-4B; Proteccion radiologica en braquiterapia intersticial y determinacion de la dosis y tasa de exposicion de una fuente de Ir-192 mediante el MCNP-4B

    Energy Technology Data Exchange (ETDEWEB)

    Morales L, M.E. [INEN, Av. Angamos Este 2520- Surquillo, Lima (Peru)

    2006-07-01

    The present work was carried out in the Neurological Sciences Institute having as objective to determine the dose and the rate of exhibition of the sources of Iridium 192, Iodine 125 and Palladium 103; which are used to carry out implant in the Interstitial Brachytherapy according to the TG43. For it we carry out a theoretical calculation, its are defined in the enter file: the geometry, materials of the problem and the radiation source, etc; in the MCNP-4B Monte Carlo code, considering a punctual source and for the dose determination we simulate thermoluminescent dosemeters (TLD): at 5 cm, 50 cm, 100 cm and 200 cm of the source. Our purpose is to analyze the radioprotection measures that should take into account in this Institute in which are carried out brain biopsies using a Micro mar stereotactic mark, and in a near future with the collaboration of a doctor and a cuban physique seeks to be carried out the Interstitial Brachytherapy technique with sources of Ir-192 for patient with tumors like glioblastoma, astrocytoma, etc. (Author)

  14. Avaliação da biodegradação de matrizes porosas à base de hidroxiapatita para aplicação como fontes radioativas em braquiterapia Evaluation of the biodegradation of porous hydroxyapatite matrices for application as radioactive sources in brachytherapy

    Directory of Open Access Journals (Sweden)

    Kássio André Lacerda

    2009-01-01

    Full Text Available Porous ceramic materials based on calcium phosphate compounds (CPC have been studied aiming at different biomedical applications such as implants, drug delivery systems and radioactive sources for brachytherapy. Two kinds of hydroxyapatite (HAp powders and their ceramic bodies were characterized by a combination of different techniques (XRF, BET method, SEM, ICP/AES and neutron activation analysis - NAA to evaluate their physico-chemical and microstructural characteristics in terms of chemical composition, segregated phases, microstructure, porosity, chemical and thermal stability, biodegradation and incorporation of substances in their structures. The results revealed that these systems presented potential for use as porous biodegradable radioactive sources able to be loaded with a wide range of radionuclides for cancer treatment by the brachytherapy technique.

  15. Relationship between two year PSA nadir and biochemical recurrence in prostate cancer patients treated with iodine-125 brachytherapy; A relacao entre PSA nadir de dois anos e recidiva bioquimica no tratamento do cancer de prostata com braquiterapia de semente de iodo-125

    Energy Technology Data Exchange (ETDEWEB)

    Franca, Carlos Antonio da Silva; Vieira, Sergio Lannes; Penna, Antonio Belmiro Rodrigues Campbell, E-mail: carlosfranca@cremerj.org.br [Instituto Brasileiro de Oncologia (IBO), Rio de Janeiro, RJ (Brazil); Radioterapia Botafogo, Rio de janeiro, RJ (Brazil); Carvalho, Antonio Carlos Pires [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil); Bernabe, Antonio Jose Serrano [Radioterapia Botafogo, Rio de janeiro, RJ (Brazil)

    2014-03-15

    Objective: to evaluate the relationship between two year PSA nadir (PSAn) after brachytherapy and biochemical recurrence rates in prostate cancer patients. Materials and methods: In the period from January 1998 to August 2007, 120 patients were treated with iodine-125 brachytherapy alone. The results analysis was based on the definition of biochemical recurrence according to the Phoenix Consensus. Results: biochemical control was observed in 86 patients (71.7%), and biochemical recurrence, in 34 (28.3%). Mean PSAn was 0.53 ng/ml. The mean follow-up was 98 months. The patients were divided into two groups: group 1, with two year PSAn < 0.5 ng/ml after brachytherapy (74 patients; 61.7%), and group 2, with two year PSAn ≥ 0.5 ng/ml after brachytherapy (46 patients; 38.3%). Group 1 presented biochemical recurrence in 15 patients (20.3%), and group 2, in 19 patients (43.2%) (p < 0.02). The analysis of biochemical disease-free survival at seven years, stratified by the two groups, showed values of 80% and 64% (p < 0.02), respectively. Conclusion: levels of two year PSAn ≥ 0.5 ng/ml after brachytherapy are strongly correlated with a poor prognosis. This fact may help to identify patients at risk for disease recurrence. (author)

  16. Attainment of dose distributions produced by different arrangements of Ir-192 wires in ocular brachytherapy treatments using the Monte Carlo method; Obtencion de distribuciones de dosis producida por diferentes arreglos de alambres de Ir-192 en tratamientos de braquiterapia ocular utilizando el metodo de Monte Carlo

    Energy Technology Data Exchange (ETDEWEB)

    Vivanco, M.G. Bernui de [Instituto Peruano de Energia Nuclear (IPEN), Lima (Peru)

    2004-07-01

    This paper has two aims: to use The Monte Carlo Simulation to find the dose distributions of brachytherapy treatment and to discover the best way to generate dose distributions for each individual ocular brachytherapy treatment. To achieve these objectives a Monte Carlo Simulation program was developed, which is referred as 'Alternativo', which specifically simulates ocular brachytherapy treatments of the type used in Peru. The results obtained using the Alternativo program are compared with those of the Penelope program, where it is found that the simulation coincide within one standard deviation. The time spent in the simulation using the Alternativo program is an average 30% less, depending on the characteristics of the simulated treatment. The simulation model is confirmed experimentally. Finally a study is made of the variation in dose occasioned by treatment characteristics (source dimensions, number of sources and their placement on the gold plate, characteristics of the plate: thickness, radius of the ophthalmic plate). The conclusion reached in this paper is that is possible to significantly reduce the time needed for ocular brachytherapy treatment simulations by creating a specific program, without significantly lowering the quality of the results. In addition ways were found that give adequate dose distributions for each individual ocular brachytherapy treatment. (author)

  17. Proposal of a postal system for Ir-192 sources calibration used in high dose rate brachytherapy with LiF:Mn:Ti thermoluminescent dosemeters; Proposta de um sistema postal para a calibracao de fontes de {sup 192} Ir, utilizadas em braquiterapia de alta taxa de dose, com dosimetros termoluminescentes de LiF: Mn: Ti

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, W.S.; Borges, J.C.; Almeida, C.E.V. [Instituto de Radioprotecao e Dosimetria. CNEN Caixa Postal 37750, 22780-160, Rio de Janeiro (Brazil)

    1998-12-31

    A proposal in order to improve the brachytherapy quality control and to allow postal intercomparison of Ir-192 sources used in high dose rate brachytherapy has been presented. The LiF: Mn: Ti (TLD 100) detector has been selected for such purpose. The experimental array and the TLDs irradiation and calibration techniques, at the treatment units, have been specified in the light of more recent methodology of Ir-192 calibration sources. (Author)

  18. In vivo Tl dosimetry for the quality control in Radiotherapy with {sup 60} Co and brachytherapy of low dose rate; Dosimetria Tl in vivo para el control de calidad en Radioterapia con {sup 60} Co y Braquiterapia de baja tasa de dosis

    Energy Technology Data Exchange (ETDEWEB)

    Velez, G.; Bustos, S.; Balmaceda, O.; Gutierrez, S.; Ferraris, M. [Servicio de Radioterapia, Hospital San Roque. Rosario de Santa Fe 374. CP 5000. Cordoba (Argentina)

    1998-12-31

    In vivo dosimetry is used every time with more frequency as a valuable tool for the quality control in Radiotherapy. The measurements of input and output doses provide us information about the technique accuracy or the treatment procedure used; likewise the dose measurement which rectum or bladder receive in gynecologic implants contribute to the improving and adjusting the procedures in brachytherapy. Besides, it may be identify systematic errors in particular situations which allow to optimize the treatment and to minimize errors. It was realized a study at the Radiotherapy service in San Roque Hospital (Cordoba) to control the procedures used in the treatment of distinct oncologic pathologies. Its were selected patients, which were realized the routine planning with the planning system of computerized treatments Prowess 3000, that later its were controlled with In vivo thermoluminescent dosimetry using the Ceprocor Services (Cordoba). Its were realized dose skin measurements in treatments of mammary gland, pelvis, thorax, head and neck and it were measured doses in body cavities, as oral cavity, rectum, esophagus, etc. arranging the TLD inside special catheters. In the case of dose skin, the dosemeters were arranged in acrylic porta-dosemeters, at pairs, which later they were enveloped and sealed. It was founded a very good agreement among the In vivo measurements and the predicted by the planner. In some cases, the control allows to modify the treatment for to avoid over or sub dosages of the distinct organs affected by the radiation field. (Author)

  19. Combination of high-dose rate brachytherapy and external beam radiotherapy for the treatment of advanced scalp angiosarcoma - case report; Braquiterapia de alta taxa de dose associada a radioterapia externa no tratamento de angiossarcoma extenso do couro cabeludo - relato de caso

    Energy Technology Data Exchange (ETDEWEB)

    Gentil, Andre Cavalcanti; Lima Junior, Carlos Genesio Bezerra [Instituto Nacional do Cancer, Rio de Janeiro, RJ (Brazil). Dept. de Radioterapia]. E-mail: andregentil@hotmail.com; Soboll, Danyel Scheidegger; Novaes, Paulo Eduardo R.S.; Pereira, Adelino Jose; Pellizon, Antonio Carlos Assis [Hospital do Cancer A.C. Camargo, Sao Paulo, SP (Brazil). Centro de Tratamento e Pequisa

    2001-10-01

    The authors report a case of a patient with an extensive angiosarcoma of the scalp that was submitted only to radiotherapy with a combination of orthovoltage roentgentherapy and high-dose rate brachytherapy, using a mould. The clinical and technical features as well as the therapeutic outcome are presented, and the usefulness and peculiarities of high-dose rate brachytherapy for this particular indication is discussed. A comparative analysis of the difficulties and limitations of employing low-dose rate brachytherapy is also presented. The authors concluded that high-dose rate brachytherapy might be an useful, practical and safe option to treat neoplastic lesions of the scalp, and an alternative treatment to electrontherapy. (author)

  20. Una técnica novedosa para corrección de prolapso rectal completo: rectopexia percutánea asistida por endoscopia con ayuda del EndoLifter

    Directory of Open Access Journals (Sweden)

    L. Bustamante-Lopez

    2016-10-01

    Conclusiones: La rectopexia percutánea asistida por endoscopia es un procedimiento endoluminal seguro y factible para la fijación del recto a la pared abdominal anterior en animales de experimentación.

  1. Stereo Vision-Based High Dynamic Range Imaging Using Differently-Exposed Image Pair.

    Science.gov (United States)

    Park, Won-Jae; Ji, Seo-Won; Kang, Seok-Jae; Jung, Seung-Won; Ko, Sung-Jea

    2017-06-22

    In this paper, a high dynamic range (HDR) imaging method based on the stereo vision system is presented. The proposed method uses differently exposed low dynamic range (LDR) images captured from a stereo camera. The stereo LDR images are first converted to initial stereo HDR images using the inverse camera response function estimated from the LDR images. However, due to the limited dynamic range of the stereo LDR camera, the radiance values in under/over-exposed regions of the initial main-view (MV) HDR image can be lost. To restore these radiance values, the proposed stereo matching and hole-filling algorithms are applied to the stereo HDR images. Specifically, the auxiliary-view (AV) HDR image is warped by using the estimated disparity between initial the stereo HDR images and then effective hole-filling is applied to the warped AV HDR image. To reconstruct the final MV HDR, the warped and hole-filled AV HDR image is fused with the initial MV HDR image using the weight map. The experimental results demonstrate objectively and subjectively that the proposed stereo HDR imaging method provides better performance compared to the conventional method.

  2. Stereo Vision-Based High Dynamic Range Imaging Using Differently-Exposed Image Pair

    Directory of Open Access Journals (Sweden)

    Won-Jae Park

    2017-06-01

    Full Text Available In this paper, a high dynamic range (HDR imaging method based on the stereo vision system is presented. The proposed method uses differently exposed low dynamic range (LDR images captured from a stereo camera. The stereo LDR images are first converted to initial stereo HDR images using the inverse camera response function estimated from the LDR images. However, due to the limited dynamic range of the stereo LDR camera, the radiance values in under/over-exposed regions of the initial main-view (MV HDR image can be lost. To restore these radiance values, the proposed stereo matching and hole-filling algorithms are applied to the stereo HDR images. Specifically, the auxiliary-view (AV HDR image is warped by using the estimated disparity between initial the stereo HDR images and then effective hole-filling is applied to the warped AV HDR image. To reconstruct the final MV HDR, the warped and hole-filled AV HDR image is fused with the initial MV HDR image using the weight map. The experimental results demonstrate objectively and subjectively that the proposed stereo HDR imaging method provides better performance compared to the conventional method.

  3. A importância do diagnóstico por imagem na classificação dos endoleaks como complicação do tratamento endovascular de aneurismas aórticos The value of diagnostic imaging in the classification of endoleaks as a complication of endoluminal grafting of aortic aneurysms

    Directory of Open Access Journals (Sweden)

    Francisco Abaeté das Chagas Neto

    2010-10-01

    Full Text Available OBJETIVO: Relatar uma série de casos de endoleaks, com descrição da classificação vigente. MATERIAIS E MÉTODOS: Realizou-se um estudo retrospectivo dos endoleaks diagnosticados em nossa instituição, entre 2005 e 2009. Foram incluídos 20 casos, utilizados para ilustrar os diferentes tipos de endoleaks. RESULTADOS: Setenta por cento dos pacientes eram do sexo masculino. A idade variou entre 43 e 91 anos, média de 76,3 anos. Treze casos foram observados na aorta abdominal infrarrenal, quatro na aorta torácica, dois nas artérias ilíacas e um no território carotídeo. A ultrassonografia foi o método utilizado para o diagnóstico em 3 casos e a tomografia computadorizada, nos outros 17 casos. Classificação: tipo I, 60%; tipo II, 25%; tipo III, 15%. Não foram observados os demais tipos nesta série. CONCLUSÃO: O diagnóstico precoce e a correta classificação são fundamentais para o manejo adequado dos casos de endoleaks, tornando o conhecimento de seus subtipos conceito fundamental na formação do médico especialista em radiologia e diagnóstico por imagem e para o cirurgião vascular.OBJECTIVE: To describe a series of endoleak cases and their respective classification. MATERIALS AND METHODS: The authors developed a retrospective study of endoleaks diagnosed at their institution in the period between 2005 and 2009. Twenty cases were included to illustrate the different types of endoleaks. RESULTS: Seventy percent of the patients were men, and the ages ranged from 43 to 91 years (mean, 76.3 years. Thirteen cases were observed in the infrarenal abdominal aorta, four in the thoracic aorta, two in the iliac artery, and one in the carotid territory. Ultrasonography was the method utilized for diagnosis in three cases, and computed tomography in the other 17 cases. Classification: 60% type I, 25% type II, 15% type III. Other endoleak types were not observed in the present series. CONCLUSION: Early diagnosis and correct classification of endoleaks are crucial for an appropriate management of cases. The knowledge of endoleaks subtypes is fundamental in the education of physicians specialized in radiology and imaging diagnosis as well as for vascular surgeons.

  4. Metal stent and endoluminal high-dose rate [sup 192]iridium brachytherapy in palliative treatment of malignant biliary tract obstruction. First experiences. Metallgeflecht-Endoprothese und intraluminare High-dose-rate-[sup 192]Iridium-Brachytherapie zur palliativen Behandlung maligner Gallengangsobstruktionen. Erste Erfahrungen

    Energy Technology Data Exchange (ETDEWEB)

    Pakisch, B.; Stuecklschweiger, G.; Poier, E.; Leitner, H.; Poschauko, J.; Hackl, A. (Universitaets-Klinik fuer Radiologie, Abt. fuer Strahlentherapie, Graz (Austria)); Klein, G.E.; Lammer, J.; Hausegger, K.A. (Universitaets-Klinik fuer Radiologie, Abt. fuer Spezielle Roentgendiagnostik und Digitale Bilddiagnostische Verfahren, Graz (Austria))

    1992-06-01

    Since December 1989, 9 patients with inoperable malignant biliary tract obstruction were treated palliatively by a combined modality treatment consisting of placement of a permanent biliary endoprosthesis followed by intraluminal high dose-rate [sup 192]Ir brachytherapy. A dose of 10 Gy was delivered in a hyperfractionated schedule at the point of reference in a distance of 7.5 mm of centre of the source. External small field radiotherapy (50.4 Gy, 1.8 Gy per day, 5 fractions per week) was also given in six cases (M/O, Karnofsky >60%). In 9/9 cases an unrestrained bile flow and an interruption of pruritus was achieved, in 78% (7/9) of cases the duration of palliation was as long as the survival time (median survival time 7.5 months). (orig.).

  5. Recommendations of the Spanish brachytherapy group (GEB) of Spanish Society of Radiation Oncology (SEOR) and the Spanish Society of Medical Physics (SEFM) for high-dose rate (HDR) non melanoma skin cancer brachytherapy.

    Science.gov (United States)

    Rodríguez, S; Arenas, M; Gutierrez, C; Richart, J; Perez-Calatayud, J; Celada, F; Santos, M; Rovirosa, A

    2017-08-14

    Clinical indications of brachytherapy in non-melanoma skin cancers, description of applicators and dosimetry recommendations are described based on the literature review, clinical practice and experience of Spanish Group of Brachytherapy and Spanish Society of Medical Physics reported in the XIV Annual Consensus Meeting on Non Melanoma Skin Cancer Brachytherapy held in Benidorm, Alicante (Spain) on October 21st, 2016. All the recommendations for which consensus was achieved are highlighted in blue. Regular and small surfaces may be treated with Leipzig, Valencia, flap applicators or electronic brachytherapy (EBT). For irregular surfaces, customized molds or interstitial implants should be employed. The dose is prescribed at a maximum depth of 3-4 mm of the clinical target volume/planning target volume (CTV/PTV) in all cases except in flaps or molds in which 5 mm is appropriate. Interstitial brachytherapy should be used for CTV/PTV >5 mm. Different total doses and fraction sizes are used with very similar clinical and toxicity results. Hypofractionation is very useful twice or 3 times a week, being comfortable for patients and practical for Radiotherapy Departments. In interstitial brachytherapy 2 fractions twice a day are applied.

  6. Molecular and functional characterization of a cDNA encoding 4-hydroxy-3-methylbut-2-enyl diphosphate reductase from Dunaliella salina.

    Science.gov (United States)

    Ramos, Ana A; Marques, Ana R; Rodrigues, Marta; Henriques, Nuno; Baumgartner, Alexandra; Castilho, Rita; Brenig, Bertram; Varela, João C

    2009-06-01

    In green algae, the final step of the plastidial methylerythritol phosphate (MEP) pathway is catalyzed by 4-hydroxy-3-methylbut-2-enyl diphosphate reductase (HDR; EC: 1.17.1.2), an enzyme proposed to play a key role in the regulation of isoprenoid biosynthesis. Here we report the isolation and functional characterization of a 1959-bp Dunaliella salina HDR (DsHDR) cDNA encoding a deduced polypeptide of 474 amino acid residues. Phylogenetic analysis implied a cyanobacterial origin for plant and algal HDR genes. Steady-state DsHDR transcript levels were higher in D. salina cells submitted to nutritional depletion, high salt and/or high light, suggesting that DsHDR may respond to the same environmental cues as genes involved in carotenoid biosynthesis.

  7. Supplemental Environmental Assessment for the Mid-Bay Bridge Connector Phases 2 and 3, Eglin Air Force Base, Florida

    Science.gov (United States)

    2010-08-03

    Qualifications Contribution Experience Brad Collins Professional Engineer B.S. Civil Engineering M.B.A. Engineering Technical Review 8 years civil...Kellner Brad Collins Mick Garrett Mid-Bay Bridge Authority HDR Engineering HDR Engineering HDR Engineering 4400 E. Hwy. 20, #403 25 W. Cedar...Discusse