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Sample records for radiotherapy including hdr

  1. Combined curative radiotherapy including HDR brachytherapy and androgen deprivation in localized prostate cancer: A prospective assessment of acute and late treatment toxicity

    International Nuclear Information System (INIS)

    Wahlgren, Thomas; Nilsson, Sten; Ryberg, Marianne; Brandberg, Yvonne; Lennernaes, Bo

    2005-01-01

    Self-reported symptoms including urinary, bowel and sexual side effects were investigated prospectively at multiple assessment points before and after combined radiotherapy of prostate cancer including HDR brachytherapy and neoadjuvant androgen deprivation therapy. Between April 2000 and June 2003, patients with predominantly advanced localized prostate tumours subjected to this treatment were asked before treatment and on follow-up visits to complete a questionnaire covering urinary, bowel and sexual problems. The mainly descriptive analyses included 525 patients, responding to at least one questionnaire before or during the period 2-34 months after radiotherapy. Adding androgen deprivation before radiotherapy significantly worsened sexual function. During radiotherapy, urinary, bowel and sexual problems increased and were reported at higher levels up to 34 months, although there seemed to be a general tendency to less pronounced irritative bowel and urinary tract symptoms over time. No side effects requiring surgery were reported. Classic late irradiation effects such as mucosal bleeding were demonstrated mainly during the second year after therapy, but appear less pronounced in comparison with dose escalated EBRT series. In conclusion, despite the high radiation dose given, the toxicity seemed comparable with that of other series but long term (5-10 years) symptom outcome has to be determined

  2. A dosimetric selectivity intercomparison of HDR brachytherapy, IMRT and helical tomotherapy in prostate cancer radiotherapy

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    Hermesse, Johanne; Biver, Sylvie; Jansen, Nicolas; Coucke, Philippe [Dept. of Radiation Oncology, Liege Univ. Hospital (Belgium); Lenaerts, Eric [Dept. of Medical Physics, Liege Univ. Hospital (Belgium); De Patoul, Nathalie; Vynckier, Stefaan [Dept. of Medical Physics, St Luc Univ. Hospital, Brussels (Belgium); Scalliet, Pierre [Dept. of Radiation Oncology, St Luc Univ. Hospital, Brussels (Belgium); Nickers, Philippe [Dept. of Radiation Oncology, Oscar Lambret Center, Lille (France)

    2009-11-15

    Background and purpose: dose escalation in order to improve the biochemical control in prostate cancer requires the application of irradiation techniques with high conformality. The dosimetric selectivity of three radiation modalities is compared: high-dose-rate brachytherapy (HDR-BT), intensity-modulated radiation radiotherapy (IMRT), and helical tomotherapy (HT). Patients and methods: ten patients with prostate adenocarcinoma treated by a 10-Gy HDR-BT boost after external-beam radiotherapy were investigated. For each patient, HDR-BT, IMRT and HT theoretical treatment plans were realized using common contour sets. A 10-Gy dose was prescribed to the planning target volume (PTV). The PTVs and critical organs' dose-volume histograms obtained were compared using Student's t-test. Results: HDR-BT delivers spontaneously higher mean doses to the PTV with smaller cold spots compared to IMRT and HT. 33% of the rectal volume received a mean HDR-BT dose of 3.86 {+-} 0.3 Gy in comparison with a mean IMRT dose of 6.57 {+-} 0.68 Gy and a mean HT dose of 5.58 {+-} 0.71 Gy (p < 0.0001). HDR-BT also enables to better spare the bladder. The hot spots inside the urethra are greater with HDR-BT. The volume of healthy tissue receiving 10% of the prescribed dose is reduced at least by a factor of 8 with HDR-BT (p < 0.0001). Conclusion: HDR-BT offers better conformality in comparison with HT and IMRT and reduces the volume of healthy tissue receiving a low dose. (orig.)

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

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    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)

  4. Balloon-based adjuvant radiotherapy in breast cancer: comparison between 99mTc and HDR 192Ir

    Directory of Open Access Journals (Sweden)

    Tarcísio Passos Ribeiro de Campos

    2016-04-01

    Full Text Available Abstract Objective: To perform a comparative dosimetric analysis, based on computer simulations, of temporary balloon implants with 99mTc and balloon brachytherapy with high-dose-rate (HDR 192Ir, 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 99mTc-filled and HDR 192Ir-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 99mTc 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 192Ir balloon. An exposure time of 24 hours was required for the 99mTc 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 192Ir 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 99mTc 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 192Ir balloon implantation, which is the current standard in clinical practice.

  5. Genitourinary Toxicity After High-Dose-Rate (HDR) Brachytherapy Combined With Hypofractionated External Beam Radiotherapy for Localized Prostate Cancer: An Analysis to Determine the Correlation Between Dose-Volume Histogram Parameters in HDR Brachytherapy and Severity of Toxicity

    International Nuclear Information System (INIS)

    Ishiyama, Hiromichi; Kitano, Masashi; Satoh, Takefumi; Kotani, Shouko; Uemae, Mineko; Matsumoto, Kazumasa; Okusa, Hiroshi; Tabata, Ken-ichi; Baba, Shiro; Hayakawa, Kazushige

    2009-01-01

    Purpose: To evaluate the severity of genitourinary (GU) toxicity in high-dose-rate (HDR) brachytherapy combined with hypofractionated external beam radiotherapy (EBRT) for prostate cancer and to explore factors that might affect the severity of GU toxicity. Methods and Materials: A total of 100 Japanese men with prostate cancer underwent 192 Ir HDR brachytherapy combined with hypofractionated EBRT. Mean (SD) dose to 90% of the planning target volume was 6.3 (0.7) Gy per fraction of HDR. After 5 fractions of HDR treatment, EBRT with 10 fractions of 3 Gy was administrated. The urethral volume receiving 1-15 Gy per fraction in HDR brachytherapy (V1-V15) and the dose to at least 5-100% of urethral volume in HDR brachytherapy (D5-D100) were compared between patients with Grade 3 toxicity and those with Grade 0-2 toxicity. Prostate volume, patient age, and International Prostate Symptom Score were also compared between the two groups. Results: Of the 100 patients, 6 displayed Grade 3 acute GU toxicity, and 12 displayed Grade 3 late GU toxicity. Regarding acute GU toxicity, values of V1, V2, V3, and V4 were significantly higher in patients with Grade 3 toxicity than in those with Grade 0-2 toxicity. Regarding late GU toxicity, values of D70, D80, V12, and V13 were significantly higher in patients with Grade 3 toxicity than in those with Grade 0-2 toxicity. Conclusions: The severity of GU toxicity in HDR brachytherapy combined with hypofractionated EBRT for prostate cancer was relatively high. The volume of prostatic urethra was associated with grade of acute GU toxicity, and urethral dose was associated with grade of late GU toxicity.

  6. Additional androgen deprivation makes the difference. Biochemical recurrence-free survival in prostate cancer patients after HDR brachytherapy and external beam radiotherapy

    International Nuclear Information System (INIS)

    Schiffmann, Jonas; Tennstedt, Pierre; Beyer, Burkhard; Boehm, Katharina; Tilki, Derya; Salomon, Georg; Graefen, Markus; Lesmana, Hans; Platz, Volker; Petersen, Cordula; Kruell, Andreas; Schwarz, Rudolf

    2015-01-01

    The role of additional androgen deprivation therapy (ADT) in prostate cancer (PCa) patients treated with combined HDR brachytherapy (HDR-BT) and external beam radiotherapy (EBRT) is still unknown. Consecutive PCa patients classified as D'Amico intermediate and high-risk who underwent HDR-BT and EBRT treatment ± ADT at our institution between January 1999 and February 2009 were assessed. Multivariable Cox regression models predicting biochemical recurrence (BCR) were performed. BCR-free survival was assessed with Kaplan-Meier analyses. Overall, 392 patients were assessable. Of these, 221 (56.4 %) underwent trimodality (HDR-BT and EBRT and ADT) and 171 (43.6 %) bimodality (HDR-BT and EBRT) treatment. Additional ADT administration reduced the risk of BCR (HR: 0.4, 95 % CI: 0.3-0.7, p < 0.001). D'Amico high-risk patients had superior BCR-free survival when additional ADT was administered (log-rank p < 0.001). No significant difference for BCR-free survival was recorded when additional ADT was administered to D'Amico intermediate-risk patients (log-rank p = 0.2). Additional ADT administration improves biochemical control in D'Amico high-risk patients when HDR-BT and EBRT are combined. Physicians should consider the oncological benefit of ADT administration for these patients during the decision-making process. (orig.) [de

  7. Additional androgen deprivation makes the difference. Biochemical recurrence-free survival in prostate cancer patients after HDR brachytherapy and external beam radiotherapy

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    Schiffmann, Jonas; Tennstedt, Pierre; Beyer, Burkhard; Boehm, Katharina; Tilki, Derya; Salomon, Georg; Graefen, Markus [University Medical Center Hamburg-Eppendorf, Martini-Clinic Prostate Cancer Center, Hamburg (Germany); Lesmana, Hans; Platz, Volker; Petersen, Cordula; Kruell, Andreas; Schwarz, Rudolf [University Medical Center Hamburg-Eppendorf, Department of Radiation oncology, Hamburg (Germany)

    2015-04-01

    The role of additional androgen deprivation therapy (ADT) in prostate cancer (PCa) patients treated with combined HDR brachytherapy (HDR-BT) and external beam radiotherapy (EBRT) is still unknown. Consecutive PCa patients classified as D'Amico intermediate and high-risk who underwent HDR-BT and EBRT treatment ± ADT at our institution between January 1999 and February 2009 were assessed. Multivariable Cox regression models predicting biochemical recurrence (BCR) were performed. BCR-free survival was assessed with Kaplan-Meier analyses. Overall, 392 patients were assessable. Of these, 221 (56.4 %) underwent trimodality (HDR-BT and EBRT and ADT) and 171 (43.6 %) bimodality (HDR-BT and EBRT) treatment. Additional ADT administration reduced the risk of BCR (HR: 0.4, 95 % CI: 0.3-0.7, p < 0.001). D'Amico high-risk patients had superior BCR-free survival when additional ADT was administered (log-rank p < 0.001). No significant difference for BCR-free survival was recorded when additional ADT was administered to D'Amico intermediate-risk patients (log-rank p = 0.2). Additional ADT administration improves biochemical control in D'Amico high-risk patients when HDR-BT and EBRT are combined. Physicians should consider the oncological benefit of ADT administration for these patients during the decision-making process. (orig.) [German] Der Nutzen einer zusaetzlichen Hormonentzugstherapie (ADT, ''androgen deprivation therapy'') fuer Patienten mit Prostatakarzinom (PCa), welche mit einer Kombination aus HDR-Brachytherapie (HDR-BT) und perkutaner Bestrahlung (EBRT) behandelt werden, ist weiterhin ungeklaert. Fuer diese Studie wurden konsekutive, nach der D'Amico-Risikoklassifizierung in ''intermediate'' und ''high-risk'' eingeteilte Patienten ausgewaehlt, die zwischen Januar 1999 und Februar 2009 in unserem Institut eine kombinierte Therapie aus HDR-BT, EBRT ± ADT erhalten haben. Eine

  8. Radical radiotherapy treatment (EBRT + HDR-ICRT of carcinoma of the uterine cervix: Outcome in patients treated at a rural center in India

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    Jain Vandana

    2007-01-01

    Full Text Available Aim: To report the outcome of carcinoma of the uterine cervix patients treated radically by external beam radiotherapy (EBRT and high-dose-rate (HDR intracavitary radiotherapy (ICRT. Materials and Methods: Between January 1997 to December 2001, a total of 550 newly diagnosed cases of carcinoma of the uterine cervix were reported in the department. All cases were staged according to the International Federation of Gynecologists and Oncologists (FIGO staging system, but for analytical convenience, the staging was limited to stages I, II, III, and IV. Out of the 550 cases, 214 completed radical radiotherapy (EBRT + HDR-ICRT and were retrospectively analyzed for presence of local residual disease, local recurrence, distant metastases, radiation reactions, and disease-free survival. Results: There were 7 (3.27%, 88 (41.1%, 101 (47.1%, and 18 (8.4% patients in stage I, II, III, and IV, respectively. The median follow-up time for all patients was 43 months (range: 3-93 months and for patients who were disease free till the last follow-up it was 59 months (range: 24-93 months. The overall treatment time (OTT ranged from 52 to 73 days (median 61 days. The 5-year disease-free mean survival rate was 58%, 44%, 33%, and 15%, with 95% confidence interval of 48 to 68, 37 to 51, 24 to 35, and 6 to 24 for stages I, II, III, and IV, respectively. There were 62 (28.97% cases with local residual disease, 35 (16.3% developed local recurrence/distant metastases, 17 (7.9% developed distant metastases, and 9 (4.2% had local recurrence as well. Discussion and Conclusion: The overall outcome was poor in advanced stage disease, but might be improved by increasing the total dose, decreasing overall duration of treatment, and by adding chemotherapy in patients with disease limited to the pelvis.

  9. Dose rate effect from the relationship between ICRU rectal dose and local control rate in intracavitary radiotherapy for carcinoma of the uterine cervix. Six fraction HDR and three-fraction LDR in three weeks

    International Nuclear Information System (INIS)

    Jingu, Kenichi; Akita, Yuzou; Ohmagari, Jyunichi

    2001-01-01

    The dose rate effect, low dose rate radiotherapy (LDR)/high dose rate radiotherapy (HDR), was calculated using the isoeffect ICRU rectal dose by intracavitary radiotherapy (ICRT) for uterine cervix cancer. The subjects analyzed consisted of 78 LDR and 74 HDR patients whose ICRU rectal dose could be calculated and whose local control as stage II/III cases could be evaluated. The point A dose in ICRT was 45-55 Gy/3 fractions/3 weeks for LDR and 30 Gy/6 fractions/3 weeks for HDR. The dose effect relationships associated with local control at each whole pelvis external radiation dose were calculated using the double integration method and Probit analysis, and the 50% and 90% local control ICRU rectal doses were calculated from this relationship. Finally, the dose rate effect LDR/HDR was determined from 50% and 90% local control doses. The dose rate effect calculated from the 50% local control dose was 1.24 and that from the 90% local control dose was 1.14. (author)

  10. 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.

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

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    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.

  12. Hydrogen dressings HDR

    International Nuclear Information System (INIS)

    Rosiak, J.M.

    1990-01-01

    Within the past several years new developments in biomaterials have enabled a significant progress in the healing of different kinds of wounds. One of such biomaterials is synthetic hydrogels. They can be formed by means of radiation technology which gives some advantages over chemical methods. Hydrogel dressings HDR have the shape of transparent foil, 3-4 mm thick, which contain over 90% water. They can be used for healing exuding wounds and especially burns, ulcers, bedsores and skin grafts. HDR dressings are sterile, transparent and mechanically resistant

  13. Viewpoint adaptive display of HDR images

    DEFF Research Database (Denmark)

    Forchhammer, Søren; Mantel, Claire

    2017-01-01

    In this paper viewpoint adaptive display of HDR images incorporating the effects of ambient light is presented and evaluated. LED backlight displays may render HDR images, but while at a global scale a high dynamic range may be achieved, locally the contrast is limited by the leakage of light...... through the LC elements of the display. To render high quality images, the display with backlight dimming can compute the values of the LED backlight and LC elements based on the input image, information about the viewpoint of the observer(s) and information of the ambient light. The goal is to achieve...... the best perceptual reproduction of the specified target image derived from the HDR input image in the specific viewing situation including multiple viewers, possibly having different preferences. An optimization based approach is presented. Some tests with reproduced images are also evaluated subjectively...

  14. Radiotherapy

    International Nuclear Information System (INIS)

    Prosnitz, L.R.; Kapp, D.S.; Weissberg, J.B.

    1983-01-01

    This review highlights developments over the past decade in radiotherapy and attempts to summarize the state of the art in the management of the major diseases in which radiotherapy has a meaningful role. The equipment, radiobiology of radiotherapy and carcinoma of the lung, breast and intestines are highlighted

  15. TU-AB-202-02: Deformable Image Registration Accuracy Between External Beam Radiotherapy and HDR Brachytherapy CT Images for Cervical Cancer Using a 3D-Printed Deformable Pelvis Phantom

    International Nuclear Information System (INIS)

    Miyasaka, Y; Kadoya, N; Ito, K; Chiba, M; Nakajima, Y; Dobashi, S; Takeda, K; Jingu, K; Kuroda, Y; Sato, K

    2016-01-01

    Purpose: Accurate deformable image registration (DIR) between external beam radiotherapy (EBRT) and HDR brachytherapy (BT) CT images in cervical cancer is challenging. DSC has been evaluated only on the basis of the consistency of the structure, and its use does not guarantee an anatomically reasonable deformation. We evaluate the DIR accuracy for cervical cancer with DSC and anatomical landmarks using a 3D-printed pelvis phantom. Methods: A 3D-printed, deformable female pelvis phantom was created on the basis of the patient’s CT image. Urethane and silicon were used as materials for creating the uterus and bladder, respectively, in the phantom. We performed DIR in two cases: case-A with a full bladder (170 ml) in both the EBRT and BT images and case-B with a full bladder in the BT image and a half bladder (100 ml) in the EBRT image. DIR was evaluated using DSCs and 70 uterus and bladder landmarks. A Hybrid intensity and structure DIR algorithm with two settings (RayStation) was used. Results: In the case-A, DSCs of the intensity-based DIR were 0.93 and 0.85 for the bladder and uterus, respectively, whereas those of hybrid-DIR were 0.98 and 0.96, respectively. The mean landmark error values of intensity-based DIR were 0.73±0.29 and 1.70±0.19 cm for the bladder and uterus, respectively, whereas those of Hybrid-DIR were 0.43±0.33 and 1.23±0.25 cm, respectively. In both cases, the Hybrid-DIR accuracy was better than the intensity-based DIR accuracy for both evaluation methods. However, for several bladder landmarks, the Hybrid-DIR landmark errors were larger than the corresponding intensity-based DIR errors (e.g., 2.26 vs 1.25 cm). Conclusion: Our results demonstrate that Hybrid-DIR can perform with a better accuracy than the intensity-based DIR for both DSC and landmark errors; however, Hybrid-DIR shows a larger landmark error for some landmarks because the technique focuses on both the structure and intensity.

  16. TU-AB-202-02: Deformable Image Registration Accuracy Between External Beam Radiotherapy and HDR Brachytherapy CT Images for Cervical Cancer Using a 3D-Printed Deformable Pelvis Phantom

    Energy Technology Data Exchange (ETDEWEB)

    Miyasaka, Y; Kadoya, N; Ito, K; Chiba, M; Nakajima, Y; Dobashi, S; Takeda, K; Jingu, K [Tohoku University Graduate School of Medicine, Sendai, Miyagi (Japan); Kuroda, Y [Cybermedia Center, Osaka University, Toyonaka, Osaka (Japan); Sato, K [Tohoku University Hospital, Sendai, Miyagi (Japan)

    2016-06-15

    Purpose: Accurate deformable image registration (DIR) between external beam radiotherapy (EBRT) and HDR brachytherapy (BT) CT images in cervical cancer is challenging. DSC has been evaluated only on the basis of the consistency of the structure, and its use does not guarantee an anatomically reasonable deformation. We evaluate the DIR accuracy for cervical cancer with DSC and anatomical landmarks using a 3D-printed pelvis phantom. Methods: A 3D-printed, deformable female pelvis phantom was created on the basis of the patient’s CT image. Urethane and silicon were used as materials for creating the uterus and bladder, respectively, in the phantom. We performed DIR in two cases: case-A with a full bladder (170 ml) in both the EBRT and BT images and case-B with a full bladder in the BT image and a half bladder (100 ml) in the EBRT image. DIR was evaluated using DSCs and 70 uterus and bladder landmarks. A Hybrid intensity and structure DIR algorithm with two settings (RayStation) was used. Results: In the case-A, DSCs of the intensity-based DIR were 0.93 and 0.85 for the bladder and uterus, respectively, whereas those of hybrid-DIR were 0.98 and 0.96, respectively. The mean landmark error values of intensity-based DIR were 0.73±0.29 and 1.70±0.19 cm for the bladder and uterus, respectively, whereas those of Hybrid-DIR were 0.43±0.33 and 1.23±0.25 cm, respectively. In both cases, the Hybrid-DIR accuracy was better than the intensity-based DIR accuracy for both evaluation methods. However, for several bladder landmarks, the Hybrid-DIR landmark errors were larger than the corresponding intensity-based DIR errors (e.g., 2.26 vs 1.25 cm). Conclusion: Our results demonstrate that Hybrid-DIR can perform with a better accuracy than the intensity-based DIR for both DSC and landmark errors; however, Hybrid-DIR shows a larger landmark error for some landmarks because the technique focuses on both the structure and intensity.

  17. Brachytherapy for Buccal Cancer: From Conventional Low Dose Rate (LDR) or Mold Technique to High Dose Rate Interstitial Brachytherapy (HDR-ISBT).

    Science.gov (United States)

    Kotsuma, Tadayuki; Yamazaki, Hideya; Masui, Koji; Yoshida, Ken; Shimizutani, Kimishige; Akiyama, Hironori; Murakami, Shumei; Isohashi, Fumiaki; Yoshioka, Yasuo; Ogawa, Kazuhiko; Tanaka, Eiichi

    2017-12-01

    To examine the effectiveness of newly-installed high-dose-rate interstitial brachytherapy (HDR-ISBT) for buccal cancer. We retrospectively reviewed 36 patients (25 men and 11 women) with buccal cancer treated with curative brachytherapy with or without external radiotherapy with a median follow-up of 99 months. A total of 15 HDR-ISBT (median 48 Gy/ 8 fractions, range=24-60 Gy) patients were compared to conventional 15 cases LDR-ISBT (70 Gy, range=42.8-110 Gy) and 7 molds techniques (15 Gy, range=9-74 Gy). A total of 31 patients also underwent external radiotherapy (30 Gy, range=24-48 Gy). They comprised of 3T1, 23 T2, 8 T3, 3 T4 including 11 node positive cases. HDR-ISBT provided 82% of local control rate at 5 years, whereas conventional brachytherapy showed 72% [p=0.44; LDR-ISBT (65%), mold therapy (85.7%)]. Patients with early lesions (T1-2 or stage I-II) showed better local control rates than those with advanced lesions (T3-4 or stage III-IV). Severe late grade 3 complications developed in two patients treated with LDR-ISBT and EBRT. There is no significant difference in toxicity grade ≤2 between conventional brachytherapy (5/15=33%) and HDR-ISBT (7/32=32%, p=0.92). HDR-ISBT achieved good and comparable local control rates to conventional brachytherapy without elevating the toxicity. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

  18. Radiotherapy

    Directory of Open Access Journals (Sweden)

    Rema Jyothirmayi

    1999-01-01

    Full Text Available Purpose. Conservative treatment in the form of limited surgery and post-operative radiotherapy is controversial in hand and foot sarcomas, both due to poor radiation tolerance of the palm and sole, and due to technical difficulties in achieving adequate margins.This paper describes the local control and survival of 41 patients with soft tissue sarcoma of the hand or foot treated with conservative surgery and radiotherapy. The acute and late toxicity of megavoltage radiotherapy to the hand and foot are described. The technical issues and details of treatment delivery are discussed. The factors influencing local control after radiotherapy are analysed.

  19. Human reliability in high dose rate afterloading radiotherapy based on FMECA

    International Nuclear Information System (INIS)

    Deng Jun; Fan Yaohua; Yue Baorong; Wei Kedao; Ren Fuli

    2012-01-01

    Objective: To put forward reasonable and feasible recommendations against the procedure with relative high risk during the high dose rate (HDR) afterloading radiotherapy, so as to enhance its clinical application safety, through studying the human reliability in the process of carrying out the HDR afterloading radiotherapy. Methods: Basic data were collected by on-site investigation and process analysis as well as expert evaluation. Failure mode, effect and criticality analysis (FMECA) employed to study the human reliability in the execution of HDR afterloading radiotherapy. Results: The FMECA model of human reliability for HDR afterloading radiotherapy was established, through which 25 procedures with relative high risk index were found,accounting for 14.1% of total 177 procedures. Conclusions: FMECA method in human reliability study for HDR afterloading radiotherapy is feasible. The countermeasures are put forward to reduce the human error, so as to provide important basis for enhancing clinical application safety of HDR afterloading radiotherapy. (authors)

  20. Under-utilisation of high-dose-rate brachytherapy boost in men with intermediate-high risk prostate cancer treated with external beam radiotherapy.

    Science.gov (United States)

    Ong, Wee Loon; Evans, Sue M; Millar, Jeremy L

    2018-04-01

    The aim of this study was to evaluate the use of high-dose-rate brachytherapy (HDR-BT) boost with definitive external beam radiotherapy (EBRT) in prostate cancer (CaP) management. The study population comprised men with intermediate-high risk CaP captured in the population-based Prostate Cancer Outcome Registry Victoria (PCOR-Vic), treated with EBRT from January 2010 to December 2015. The primary outcome is the proportion of men who received HDR-BT boost. Multivariate logistic regressions were used to evaluate the effect of patient-, tumour- and treatment-factors on the likelihood of HDR-BT use. Medicare Benefit Schedule (MBS) data was accessed to evaluate the Australia-wide pattern of HDR-BT use. One thousand eight hundred and six patients were included in this study - 886 (49%) intermediate-risk, and 920 (51%) high-risk CaP patients. Overall, only 124 (7%) patients had EBRT + HDR-BT - 47 (5%) intermediate-risk and 77 (8%) high-risk CaP patients (P = 0.01). There is higher proportion of patients who had HDR-BT in public institutions (7% public vs. 3% private, P = 0.005) and in metropolitan centres (9% metropolitan vs. 2% regional, P Victorian men with CaP. The decline in HDR-BT use was also observed nationally. © 2017 The Royal Australian and New Zealand College of Radiologists.

  1. Radiotherapy

    International Nuclear Information System (INIS)

    Zedgenidze, G.A.; Kulikov, V.A.; Mardynskij, Yu.S.

    1984-01-01

    The technique for roentgenotopometric and medicamentous preparation of patients for radiotherapy has been reported in detail. The features of planning and performing of remote, intracavitary and combined therapy in urinary bladder cancer are considered. The more effective methods of radiotherapy have been proposed taking into account own experience as well as literature data. The comparative evaluation of treatment results and prognosis are given. Radiation pathomorphism of tumors and tissues of urinary bladder is considered in detail. The problems of diagnosis, prophylaxis and treatment of complications following radiodiagnosis and radiotherapy in patients with urinary bladder cancer are illustrated widely

  2. Clinical target volume delineation including elective nodal irradiation in preoperative and definitive radiotherapy of pancreatic cancer

    Directory of Open Access Journals (Sweden)

    Caravatta Luciana

    2012-06-01

    Full Text Available Abstract Background Radiotherapy (RT is widely used in the treatment of pancreatic cancer. Currently, recommendation has been given for the delineation of the clinical target volume (CTV in adjuvant RT. Based on recently reviewed pathologic data, the aim of this study is to propose criteria for the CTV definition and delineation including elective nodal irradiation (ENI in the preoperative and definitive treatment of pancreatic cancer. Methods The anatomical structures of interest, as well as the abdominal vasculature were identified on intravenous contrast-enhanced CT scans of two different patients with pancreatic cancer of the head and the body. To delineate the lymph node area, a margin of 10 mm was added to the arteries. Results We proposed a set of guidelines for elective treatment of high-risk nodal areas and CTV delineation. Reference CT images were provided. Conclusions The proposed guidelines could be used for preoperative or definitive RT for carcinoma of the head and body of the pancreas. Further clinical investigations are needed to validate the defined CTVs.

  3. A rectum shield for the circular applicator system of a selectron unit (HDR and LDR afterloading)

    International Nuclear Information System (INIS)

    Hetzel, H.; McCoy, M.; Kamleitner, H.; Frommhold, H.

    1987-01-01

    In order to decrease the morbidity rate after combined radiotherapy of the cervix carcinoma, a tungsten shield 3 and 5 mm thick for the rectum has been developed by the authors which is applied with the ring and pin applicator of the selectron unit (LDR and HDR afterloading). The isodose curves were measured in a plexiglas phantom, and the radiation dose at the reference points was determined by means of a ionization dosemeter. The phantom measurements were performed with the same arrangement of sources as applied in radiotherapy. The measurements showed a dose reduction at point Rmax of 33% (HDR) and 44% (LDR) with the tungsten shield 5 mm thick. (orig.) [de

  4. Combined modality treatment including intraoperative radiotherapy in locally advanced and recurrent rectal cancer

    International Nuclear Information System (INIS)

    Tveit, Kjell Maque; Wiig, Johan N.; Olsen, Dag Rune; Storaas, Andreas; Poulsen, Jan Peter; Giercksky, Karl-Erik

    1997-01-01

    Background: Treatment of locally advanced and recurrent rectal cancer usually has a high local recurrence rate and poor survival. Promising results have been reported by combined external radiotherapy, extensive surgery and intraoperative radiotherapy (IORT). Methods: One hundred fifteen patients with locally advanced rectal cancers fixed to the pelvic wall or locally recurrent rectal cancers underwent preoperative external radiotherapy with 46-50 Gy. Six to 8 weeks later radical pelvic surgery was attempted, and was combined with intraoperative electron beam radiotherapy (15-20 Gy) in 66 patients. The patients were followed closely to evaluate complication rate, local and distant recurrence rate and survival. Results: Surgery with no macroscopic tumour remaining was obtained in 65% of the patients with no postoperative deaths. Pelvic infection was the major complication (21%). Although the observation time is short (3-60 months), the local recurrence rate seems low (22%) and survival seems promising (about 60% at 4 years) in patients with complete tumour resection, in contrast to patients with residual tumour (none living at 4 years). Conclusions: The combined modality treatment with preoperative external radiotherapy and extensive pelvic surgery with IORT is sufficiently promising to start a randomized trial on the clinical value of IORT as a boost treatment in the multidisciplinary approach to this disease

  5. Intraoperative HDR implant boost for breast cancer (preliminary results)

    International Nuclear Information System (INIS)

    Rodriguez, I.; Torre, M. de la; Gonzalez, E.; Bourel, V.

    1996-01-01

    Introduction: In spite of the fact that it is been discussed whether or not a boost is necessary for all conservative treated breast cancer patients, it is a generalized radiotherapy practice. Since september 1993 we developed a breast conservative protocol for early stage breast cancer (T1-T2) with intraoperative HDR implant boost. Side effects, cosmetic results and recurrence rates are reviewed. Method and Material: From September 1993 we treated 55 patients with intraoperative HDR implant boost to the lumpectomy site for clinical T1 or T2 invasive breast cancer, followed by external megavoltage radiotherapy to the entire breast. We used the Nucletron microselectron HDR remote afterloading system with flexible implant tubes. The geometric distribution of the tubes was performed according to the 'Paris' configuration. Each implant was evaluated by calculating the dose-volume natural histograms. The HDR fractionation schedule consists of three fractions of 4.5Gy each given at least 48 hs apart, and starting between 48-72hs from surgical procedure. The external radiotherapy to the entire breast started one week after the completion of brachytherapy, using conventional fractionation of 5 fractions per week, 1,8Gy per fraction up to 45-50Gy. Results: So far there is not any local recurrence, but medium follow up is only 18 months. We did not observe any acute damage and the cosmetic outcome was 60% excellent, 30% good and 10% acceptable. Two patients developed localized fibrosis, in both the implant involved the submamary fold. Conclusion: The intraoperative implant is the most accurate way to localize the lumpectomy site, to define the target volume, decrease the total treatment time and avoid a second anesthetic procedure without delaying the inpatient time or the initial wound healing process

  6. Radiotherapy

    International Nuclear Information System (INIS)

    Wannenmacher, M.; Debus, J.; Wenz, F.

    2006-01-01

    The book is focussed on the actual knowledge on the clinical radiotherapy and radio-oncology. Besides fundamental and general contributions specific organ systems are treated in detail. The book contains the following contributions: Basic principles, radiobiological fundamentals, physical background, radiation pathology, basics and technique of brachytherapy, methodology and technique of the stereotactic radiosurgery, whole-body irradiation, operative radiotherapy, hadron therapy, hpyerthermia, combined radio-chemo-therapy, biometric clinical studies, intensity modulated radiotherapy, side effects, oncological diagnostics; central nervous system and sense organs, head-neck carcinomas, breast cancer, thorax organs, esophagus carcinoma, stomach carcinoma, pancreas carcinoma, heptabiliary cancer and liver metastases, rectal carcinomas, kidney and urinary tract, prostate carcinoma, testicular carcinoma, female pelvis, lymphatic system carcinomas, soft tissue carcinoma, skin cancer, bone metastases, pediatric tumors, nonmalignant diseases, emergency in radio-oncology, supporting therapy, palliative therapy

  7. Feasibility and early results of interstitial intensity-modulated HDR/PDR brachytherapy (IMBT) with/without complementary external-beam radiotherapy and extended surgery in recurrent pelvic colorectal cancer

    International Nuclear Information System (INIS)

    Tepel, J.; Bokelmann, F.; Faendrich, F.; Kremer, B.; Schmid, A.; Kovacs, G.; University Hospital of Schleswig-Holstein, Kiel

    2005-01-01

    Background: A new multimodality treatment concept consisting of extended resection and postoperative fractionated intensity-modulated interstitial brachytherapy (IMBT) was introduced for pelvic recurrence of colorectal carcinoma. Patients and Methods: 46 patients received extended resection and single plastic tubes were sutured directly onto the tumor bed. IMBT was started within 2 weeks postoperatively with a median dose of 24.5 Gy (5-35 Gy). Patients were treated either with high-dose-rate brachytherapy (HDR; n=23) or with pulsed-dose-rate brachytherapy (PDR; n=23). 25 patients received complementary 45-Gy external-beam irradiation (EBRT) to the pelvic region after explanting the plastic tubes. Results: Median follow-up was 20.6 months (7-107 months) and mean patient survival 25.7±25.8 months (median 17, range 1-107 months). After 5 years overall survival, disease-free survival and local control rate were 23%, 20% and 33%, significantly influenced by the resectional state. There was a trend in favor of PDR compared to HDR, which reached statistical significance in patients who had not received additional EBRT. Conclusion: The combination of extended surgery and postoperative interstitial IMBT is feasible and offers effective interdisciplinary treatment of recurrent colorectal cancer. In this small and inhomogeneous cohort of patients PDR seems to be more effective than HDR, particularly when application of complementary EBRT is not possible. None of the patients who required resection of distant metastasis survived >2 years in this study. (orig.)

  8. Radiotherapy.

    Science.gov (United States)

    Krause, Sonja; Debus, Jürgen; Neuhof, Dirk

    2011-01-01

    Solitary plasmocytoma occurring in bone (solitary plasmocytoma of the bone, SBP) or in soft tissue (extramedullary plasmocytoma, EP) can be treated effectively and with little toxicity by local radiotherapy. Ten-year local control rates of up to 90% can be achieved. Patients with multiple myeloma often suffer from symptoms such as pain or neurological impairments that are amenable to palliative radiotherapy. In a palliative setting, short treatment schedules and lower radiation doses are used to reduce toxicity and duration of hospitalization. In future, low-dose total body irradiation (TBI) may play a role in a potentially curative regimen with nonmyeloablative conditioning followed by allogenic peripheral blood stem cell transplantation.

  9. 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.

  10. Radiotherapy

    International Nuclear Information System (INIS)

    Pistenma, D.A.

    1980-01-01

    The need for radiotherapy research is exemplified by the 100,000 cancer patients who will fail treatment locally and/or regionally annually for the next several years but who would benefit from better local treatment modalities. Theoretically, all of the areas of investigation discussed in this projection paper have the potential to significantly improve local-regional treatment of cancer by radiotherapy alone or in combination with other modalities. In many of the areas of investigation discussed in this paper encouraging results have been obtained in cellular and animal tumor studies and in limited studies in humans as well. In the not too distant future the number of patients who would benefit from better local control may increase by tens of thousands if developments in chemotherapy and/or immunotherapy provide a means to eradicate disseminated microscopic foci of cancer. Thus the efforts to improve local-regional control take on even greater significance

  11. Value of palliation and improvement in quality of life in oesophageal cancer patients treated with iridium - 192 HDR fractionated brachytherapy

    International Nuclear Information System (INIS)

    Biaias, B.; Kaleta, R.; Fijaikowski, M.

    1996-01-01

    During December 1992 - November 1995 twenty-two patients with oesophageal cancer were treated with palliative HDR brachytherapy. Sixteen patients had local recurrence or progression after external radiotherapy and the remaining six patients were treated with brachytherapy alone. All patients received fractions of 7.5 Gy at the reference point 2 - 4 time weekly. Reference point was calculated at 0.5 cm distance from applicator surface. Microselectron HDR device with Iridium-192 source were used. Criteria for palliative effect were as follow: relive of symptoms time of occurrence and duration of palliative effect. Quality of life during and after treatment were evaluated by patients and staff independently. In majority of patients both palliative effect and significant improvement of quality of life were noted. Detail results include: - improvement in swallowing in 63,6% ((14(22))); - increase in body weight in 45% ((10(22))); - pain relive 70% ((12(17))); - appearance of palliation 1 hour - 8 days; - duration of palliation - 3-12 mo. (median 5 mo.); Quality of live - improvement - 59% ((13(22))); - no improvement - 27.3% ((6(22))); - worsening - 13.7% ((3(22))); No improvement or worsening in quality of life were observed only in patients who obtained radical radiotherapy previously. Brachytherapy is an effective method of palliative treatment for as well primary and recurrent oesophageal cancer

  12. A Dosimetric Comparison of Breast Radiotherapy Techniques to Treat Locoregional Lymph Nodes Including the Internal Mammary Chain.

    Science.gov (United States)

    Ranger, A; Dunlop, A; Hutchinson, K; Convery, H; Maclennan, M K; Chantler, H; Twyman, N; Rose, C; McQuaid, D; Amos, R A; Griffin, C; deSouza, N M; Donovan, E; Harris, E; Coles, C E; Kirby, A

    2018-06-01

    Radiotherapy target volumes in early breast cancer treatment increasingly include the internal mammary chain (IMC). In order to maximise survival benefits of IMC radiotherapy, doses to the heart and lung should be minimised. This dosimetry study compared the ability of three-dimensional conformal radiotherapy, arc therapy and proton beam therapy (PBT) techniques with and without breath-hold to achieve target volume constraints while minimising dose to organs at risk (OARs). In 14 patients' datasets, seven IMC radiotherapy techniques were compared: wide tangent (WT) three-dimensional conformal radiotherapy, volumetric-modulated arc therapy (VMAT) and PBT, each in voluntary deep inspiratory breath-hold (vDIBH) and free breathing (FB), and tomotherapy in FB only. Target volume coverage and OAR doses were measured for each technique. These were compared using a one-way ANOVA with all pairwise comparisons tested using Bonferroni's multiple comparisons test, with adjusted P-values ≤ 0.05 indicating statistical significance. One hundred per cent of WT(vDIBH), 43% of WT(FB), 100% of VMAT(vDIBH), 86% of VMAT(FB), 100% of tomotherapy FB and 100% of PBT plans in vDIBH and FB passed all mandatory constraints. However, coverage of the IMC with 90% of the prescribed dose was significantly better than all other techniques using VMAT(vDIBH), PBT(vDIBH) and PBT(FB) (mean IMC coverage ± 1 standard deviation = 96.0% ± 4.3, 99.8% ± 0.3 and 99.0% ± 0.2, respectively). The mean heart dose was significantly reduced in vDIBH compared with FB for both the WT (P FB). Simple WT radiotherapy delivered in vDIBH achieves satisfactory coverage of the IMC while meeting heart and lung dose constraints. However, where higher isodose coverage is required, VMAT(vDIBH) is the optimal photon technique. The lowest OAR doses are achieved by PBT, in which the use of vDIBH does not improve dose statistics. Crown Copyright © 2018. Published by Elsevier Ltd. All rights reserved.

  13. Quality assurance of Vari-source high dose rate (HDR) brachytherapy- remote after loader and cost effectiveness of Vari-source HDR- brachytherapy: NORI, Islamabad experience

    International Nuclear Information System (INIS)

    Ahmad, N.; Mahmood, H.; Jafri, S.R.A.

    2004-01-01

    A quality control of Vari-Source high dose rate (HDR) remote after loading brachytherapy machine was carried out and the cost effectiveness of HDR brachytherapy machine was also evaluated considering the cost of ten Iridium-192 wire sources at Nuclear Medicine, Oncology and Radiotherapy Institute (NORI), Islamabad, Pakistan. A total number of 253 intracavitary insertions were done in 98 patients from October 1996 to May 2001. The results of the quality control tests performed during 1996 to 2001 were within the acceptable limits. The cost effectiveness of Vari-Source HDR brachytherapy machine was also evaluated. The average cost per patient was calculated as US$ 491. Small number of patients was treated as the machine was used for gynecologic malignancies only. The objective was to assess the quality control status of HDR brachytherapy machine on patient treatment day, source exchange day and periodic day (monthly basis). It was found that the cost per patient can be minimized if other type of cancer patients are also treated on Vari-Source HDR machine. (author)

  14. SU-D-19A-07: Dosimetric Comparison of HDR Plesiotherapy and Electron Beam Therapy for Superficial Lesions

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, A; Jacob, D; Andreou, K; Raben, A; Chen, H; Koprowski, C; Mourtada, F [Christiana Care Hospital, Newark, DE (United States)

    2014-06-01

    Purpose: Large superficial (skin, soft tissue sarcoma) lesions located on curved areas are hard to treat with electrons. The Freiburg Flap (Nucletron, Netherlands) is a flexible mesh style surface which can be easily shaped to fit curved surfaces for reproducible HDR fraction delivery. To understand the fundamental dosimetric differences, a dosimetric comparison was made between HDR plesiotherapy (Freiburg applicator for lesions over 4cm) and external electron beam radiotherapy over cases with varying target curvature (both stylized and clinical cases). Methods: Four stylized cases with variable complexity were created using artificial DICOM axial CT slices and RT structures (a square and three curved structures on a 4.5cm radius cylinder). They were planned using Oncentra v4.3 and exported to Pinnacle v9.6 for electrons planning. The HDR source dwell positions were optimized for the best coverage of the targets using graphical optimization. Electron treatment plans were created in Pinnacle using the same CT and RT structures of three HDR cases with surface lesions previously treated with the Freiburg flap. The En face electron plans used 6-12 MeV electrons and 0.5–1 cm bolus was added to increase surface dose. The electron plans were prescribed to an isodose line to conform to the target. Results: For all lesions, the average target dose coverage was similar (D90ave of 100% for HDR vs 101% for electrons). For lesions with high curvature, the HDR coverage was better (D90 102% vs D90 97% for electron). For all cases, adjacent structures high dose region was lower for HDR than electrons (D1cc 100% for HDR vs D1cc 111% for electrons). Conclusion: HDR plesiotherapy offers excellent target conformity for superficial targets similar to electrons. However, for lesions with complex curved surfaces, HDR has the advantage to achieve better dose distributions using graphical optimization to spare adjacent normal tissue while maximizing target coverage.

  15. Definitive radiotherapy based on HDR brachytherapy with iridium 192 in uterine cervix carcinoma: report on the Vienna University Hospital findings (1993-1997) compared to the preceding period in the context of ICRU 38 recommendations

    International Nuclear Information System (INIS)

    Potter, R.; Knocke, T.H.; Fellner, C.; Baldass, M.; Reinthaller, A.; Kucera, H.

    2000-01-01

    According to the reports described in the literature, fractionated HDR brachytherapy seems to represent one option for the primary treatment of cervical carcinoma. In order to render such treatment transparent and comparable for those interested in the field, we have attempted to report our recent experience obtained in Vienna from 1993-1997 using the terminology proposed by the ICRU report 38, focusing in particular on dose and volume reporting and a linear-quadratic model. Based on these parameters, a comparison with the preceding period in Vienna (LDR/HDR) has been made, with an attempt to correlate different methods and parameters with outcome. One hundred and eighty-nine patients (mean age 67 years) were treated with curative intent (stage la: 2,lb: 11, II a:11, IIb: 79, IIIa: 59, IVa: 5, IVb: 3 patients) using a combination of intra-cervical high-dose rate (HDR) brachytherapy (ring-tandem applicator) and a box technique for external-beam therapy (EBT: 48.6-50 Gy, linac 25 MV). Small tumors were treated with 5-6 fractions of 7 Gy at point A and 50 Gy EBT (25 Gy in the brachytherapy reference volume) which is iso-effective to 76-86 Gy at point A. Large tumors received 3-4 fractions of 7 Gy after 50 Gy EBT with open fields, which is iso-effective to 82-92 Gy ar point A. TRAK varied from mean 1.4 cGy (3 fractions) to 2.8 Gy (6 fractions) at one meter. 3-D treatment planning for brachytherapy was based on conventional X-rays and in 181/189 patients on computed tomography (CT) with the applicator in place. Computer-calculated volumes of the brachytherapy reference isodose (7 Gy/fraction) ranged from 46-155 ccm (mean 87 ccm); the respective mean hwt-volume (height x width x thickness) was 180 ccm. The 60 Gy HWT volumes (25 Gy from EBT) for the irradiation of small tumors ranged from 240 to 407 ccm (mean 337 ccm) and for larger tumors (50 Gy for EBT) from 452 to 785 ccm (mean 607 ccm). The beam dose for brachytherapy was 16.2 Gy (6.2-37.8 Gy) at the ICRU rectum

  16. 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

  17. Clinical problems of multiple primary cancers including head and neck cancers. From the viewpoint of radiotherapy

    International Nuclear Information System (INIS)

    Nishio, Masamichi; Myojin, Miyako; Nishiyama, Noriaki; Taguchi, Hiroshi; Takagi, Masaru; Tanaka, Katsuhiko

    2003-01-01

    A total of 2144 head and neck cancers were treated by radiotherapy at the National Sapporo Hospital between 1974 and 2001. Of these, 313 (14.6%) were found to have other primary cancers besides head and neck cancer, in which double cancers were 79% and triple or more cancers were 21%. Frequency according to primary site of the first head and neck cancer was oral cavity: 107/603 (17.7%), epipharynx cancer: 7/117 (6.0%), oropharyngeal cancer: 63/257 (24.5%), hypopharyngeal cancer: 65/200 (32.5%), laryngeal cancer: 114/558 (20.4%), and nose/paranasal sinus: 4.9% respectively. Esophageal cancer, head and neck cancer, lung cancer and gastric cancer were very frequent as other primary sites combined with the head and neck. The first onset region was the head and neck in 233 out of 313 cases with multiple primary cancers. The five-year survival rate from the onset of head and neck cancers is 52%, 10-year: 30%, and 5-year cause-specific survival rate 82%, and 10-year: 78%, respectively. The treatment possibilities in multiple primary cancers tend to be limited because the treatment areas are sometimes overlapped. New approaches to the treatment of multiple primary cancers should be considered in the future. (author)

  18. The radiobiology of prostate cancer including new aspects of fractionated radiotherapy

    International Nuclear Information System (INIS)

    Fowler, Jack F.

    2005-01-01

    Total radiation dose is not a reliable measure of biological effect when dose-per-fraction or dose-rate is changed. Large differences in biological effectiveness (per gray) are seen between the 2 Gy doses of external beam radiotherapy and the large boost doses given at high dose-rate from afterloading sources. The effects are profoundly different in rapidly or slowly proliferating tissues, that is for most tumors versus late complications. These differences work the opposite way round for prostate tumors versus late complications compared with most other types of tumor. Using the Linear-Quadratic formula it is aimed to explain these differences, especially for treatments of prostate cancer. The unusually slow growth rate of prostate cancers is associated with their high sensitivity to increased fraction size, so a large number of small fractions, such as 35 or 40 'daily' doses of 2 Gy, is not an optimum treatment. Theoretical modeling shows a stronger enhancement of tumor effect than of late complications for larger (and fewer) fractions, in prostate tumors uniquely. Biologically Effective Doses and Normalized Total Doses (in 2 Gy fraction equivalents) are given for prostate tumor, late rectal reactions, and - a new development - acute rectal mucosa. Tables showing the change of fraction-size sensitivity (the alpha/beta ratio) with proliferation rates of tissues lead to the association of slow cell doubling times in prostate tumors with small alpha/beta ratios. Clinical evidence to confirm this biological expectation is reviewed. The alpha/beta ratios of prostate tumors appear to be as low as 1.5 Gy (95% confidence interval 1.3-1.8 Gy), in contrast with the value of about 10 Gy for most other types of tumor. The important point is that alpha/beta ratio=1.5 Gy appears to be significantly less than the alpha/beta ratio=3 Gy for late complications in rectal tissues. Such differences are also emerging from recent clinical results. From this important difference stems

  19. WE-G-BRC-02: Risk Assessment for HDR Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Mayadev, J. [UC Davis Comprehensive Cancer Center (United States)

    2016-06-15

    Failure Mode and Effects Analysis (FMEA) originated as an industrial engineering technique used for risk management and safety improvement of complex processes. In the context of radiotherapy, the AAPM Task Group 100 advocates FMEA as the framework of choice for establishing clinical quality management protocols. However, there is concern that widespread adoption of FMEA in radiation oncology will be hampered by the perception that implementation of the tool will have a steep learning curve, be extremely time consuming and labor intensive, and require additional resources. To overcome these preconceptions and facilitate the introduction of the tool into clinical practice, the medical physics community must be educated in the use of this tool and the ease in which it can be implemented. Organizations with experience in FMEA should share their knowledge with others in order to increase the implementation, effectiveness and productivity of the tool. This session will include a brief, general introduction to FMEA followed by a focus on practical aspects of implementing FMEA for specific clinical procedures including HDR brachytherapy, physics plan review and radiosurgery. A description of common equipment and devices used in these procedures and how to characterize new devices for safe use in patient treatments will be presented. This will be followed by a discussion of how to customize FMEA techniques and templates to one’s own clinic. Finally, cases of common failure modes for specific procedures (described previously) will be shown and recommended intervention methodologies and outcomes reviewed. Learning Objectives: Understand the general concept of failure mode and effect analysis Learn how to characterize new equipment for safety Be able to identify potential failure modes for specific procedures and learn mitigation techniques Be able to customize FMEA examples and templates for use in any clinic.

  20. WE-G-BRC-02: Risk Assessment for HDR Brachytherapy

    International Nuclear Information System (INIS)

    Mayadev, J.

    2016-01-01

    Failure Mode and Effects Analysis (FMEA) originated as an industrial engineering technique used for risk management and safety improvement of complex processes. In the context of radiotherapy, the AAPM Task Group 100 advocates FMEA as the framework of choice for establishing clinical quality management protocols. However, there is concern that widespread adoption of FMEA in radiation oncology will be hampered by the perception that implementation of the tool will have a steep learning curve, be extremely time consuming and labor intensive, and require additional resources. To overcome these preconceptions and facilitate the introduction of the tool into clinical practice, the medical physics community must be educated in the use of this tool and the ease in which it can be implemented. Organizations with experience in FMEA should share their knowledge with others in order to increase the implementation, effectiveness and productivity of the tool. This session will include a brief, general introduction to FMEA followed by a focus on practical aspects of implementing FMEA for specific clinical procedures including HDR brachytherapy, physics plan review and radiosurgery. A description of common equipment and devices used in these procedures and how to characterize new devices for safe use in patient treatments will be presented. This will be followed by a discussion of how to customize FMEA techniques and templates to one’s own clinic. Finally, cases of common failure modes for specific procedures (described previously) will be shown and recommended intervention methodologies and outcomes reviewed. Learning Objectives: Understand the general concept of failure mode and effect analysis Learn how to characterize new equipment for safety Be able to identify potential failure modes for specific procedures and learn mitigation techniques Be able to customize FMEA examples and templates for use in any clinic

  1. Fricke gel-layer dosimetry in HDR brachytherapy

    International Nuclear Information System (INIS)

    Gambarini, G.; Negri, A.; Carrara, M.; Marchesini, R.

    2008-01-01

    Full text: In the last decade, technological improvements in radiotherapy have been significant and consequently the use and importance of radiotherapy in cancer treatment have increased greatly. In brachytherapy, new possibilities have been opened by the impressive progresses in 3D imaging, by the development of sophisticated techniques for modern afterloaders and by the constantly increasing speed and capacity of computers. However, these methodological improvements require corresponding improvements in the dosimetry methods, in order to ensure that the values calculated with computer treatment planning systems, adopted in the clinical praxis, agree with the delivered dose distributions. Fricke gel-layer dosimeters (FGLD) are under study by our group as a reliable alternative to films, semiconductors arrays or thermoluminescent dosimeters (TLDs). In the last years, we have significantly improved this technique by defining the FGLD best chemical composition, by optimizing the image acquisition assessment and by developing a dedicated software for image analysis. In this study, experimental measurements of planar dose distributions of a clinical 192 Ir source (Microselectron HDR, Nucletron) obtained by irradiating a series of piled-up FGL dosimeters in a tissue-equivalent phantom are presented. The obtained results were in accordance to TLD measurements and to treatment planning system (Plato, Nucletron) calculations. FGLD have proven to be a reliable tool to achieve HDR brachytherapy dose distribution measurements

  2. The relative efficacy of HDR and LDR interstitial brachytherapy in squamous cell carcinoma of vagina

    International Nuclear Information System (INIS)

    Demanes, D. J.; Hsu, I-C.; Lin, S.; Ewing, T.; Rodriguez, R.

    1996-01-01

    Introduction: Beginning in 1982 we performed low dose rate (LDR) interstitial template brachytherapy (ISTB) for carcinoma of the vagina. High dose rate (HDR) remote afterloading has been used exclusively since 1991. We compare the results LDR and HDR brachytherapy. Material and Methods: Between 1982 and 1994, 30 patients with primary squamous cell carcinoma of vagina received external beam radiotherapy (EBRT) and brachytherapy. The AJCC stage distribution was 3 stage I, 25 stage II, and 2 stage III. The average central pelvic EBRT dose was 35 Gy. Pelvic side wall EBRT doses ranged from 45 to 50.4 Gy. Nineteen patients had LDR treatment; 3 intracavitary brachytherapy (ICB) and 16 ISTB. Eleven patients had HDR treatment; 2 ICB and 9 ISB. The average dose delivered by LDR was 41.2 Gy usually in 2 fractions, and by HDR 32.5 Gy in 6 fractions of 500-550 cGy. Local failures were confirmed pathologically. The absolute survival (AS) and relapse-free survival (RFS) were calculated using Kaplan-Meier method and compared with logrank statistics. Results: The mean follow-up was 77 months for LDR and 23 months for HDR. Local and regional control was achieved in 90% (27/30) of the patients. Three year AS was 84% and RFS was 87%. There was no significant difference between LDR and HDR in AS, RFS or local-regional control, (log rank p=0.85, p=0.12 and p=0.35 respectively). The single HDR local failure presented in a patient with extensive stage II disease who declined ISTB. There were fewer complications following HDR. The 1 case of extensive vaginal necrosis and the 3 cases of rectovaginal fistula that required surgery occurred only with LDR brachytherapy. Discussion: Excellent local and regional control of carcinoma of the vagina can be achieved by administering limited doses of external radiation and brachytherapy. Interstitial template implants are the best means of encompassing paravaginal disease while sparing the adjacent uninvolved normal tissues from high doses of

  3. Acute cardiotoxicity with concurrent trastuzumab and radiotherapy including internal mammary chain nodes: A retrospective single-institution study

    International Nuclear Information System (INIS)

    Shaffer, Richard; Tyldesley, Scott; Rolles, Martin; Chia, Stephen; Mohamed, Islam

    2009-01-01

    Purpose: To examine the acute cardiotoxicity of internal mammary chain (IMC) irradiation with concurrent trastuzumab. Materials and Methods: Clinical and cardiac function data were collected on 59 patients with early breast cancer who were treated with adjuvant trastuzumab and chemotherapy with or without radiotherapy (often including IMC) at BC Cancer Agency in 2005. Results: Forty-four of fifty-nine patients received adjuvant radiotherapy (RT). Thirteen had left-sided IMC RT. For left-sided RT, IMC inclusion increased the mean percentage dose to 5% of the heart, but the mean doses to 50% and 90% of the heart were similar. Median baseline left ventricular ejection fraction (LVEF) was 62% and similar in all groups. Median absolute decrease in LVEF after RT was 4%, which was not significantly different according to side or inclusion of IMCs. Trastuzumab was stopped in 11 of 59 patients (18.6%) due to decrease in LVEF. After median follow up of 15 months, three patients developed clinical congestive heart failure, none of whom received left-sided IMC RT. Conclusions: There was no excess acute cardiotoxicity observed with the combination of left-sided IMC irradiation and concurrent trastuzumab

  4. Success Stories in Radiotherapy Development Projects: Radiotherapy Service in Mauritania. Chapter 28.5

    International Nuclear Information System (INIS)

    Rosenblatt, E.; Zubizarreta, E.; Djeutie, A.; Meghzifene, A.; Mohamedou, M.M.

    2017-01-01

    Mauritania, a country of 3.4 million people, did not have any radiotherapy facility until 2009. As is usually the case in countries without radiotherapy services, cancer patients with a need for this treatment travelled to neighbouring countries (Morocco or Tunisia) or to Europe to receive it, or switched to alternative forms of care. Cancer is a rising cause of death in Mauritania. According to WHO estimates, about 2200 people died of cancer in 2011, of whom 1400 were aged below 70 years of age. The number of patients sent abroad for treatment by the National Health Insurance Fund rose to 500 patients in 2007, causing a significant drain on the State budget. Cancer was the main cause of health related travel abroad. The average cost of such travel was two million ouguiya per patient (US $8000). Through a technical cooperation project initiated in 2009 between the Mauritanian Government and the IAEA, the latter assisted the country with the establishment and operation of its first radiotherapy facility. The National Oncology Centre, including a radiotherapy department, was built in Nouakchott in 2010 and began operation in early 2011 with a limited staff, all hired from abroad. Its equipment includes a modern medical linac with a multileaf collimator and portal imaging, a CT simulator, a 3-D CRT TPS and a remote afterloading HDR brachytherapy system. The centre was planned with an additional bunker, where a second accelerator can be installed in the future. Except for the training of the Department Head, the entire professional team has been trained through the IAEA’s technical cooperation fellowship programme. The centre treated a total of 250 patients in 2012 and treated 176 in the first half of 2013. Most patients undergo simulation and computerized radiotherapy treatment planning. The centre ensures the sustainability of the equipment through full maintenance contracts for the major radiation equipment and source replacements for the HDR brachytherapy unit.

  5. Dosimetric comparison of vaginal vault ovoid brachytherapy versus intensity-modulated radiation therapy plans in postoperative patients of cervical carcinoma following whole pelvic radiotherapy

    Directory of Open Access Journals (Sweden)

    Divya Khosla

    2014-01-01

    Full Text Available Introduction: Dosimetric study to compare high dose rate (HDR vaginal vault ovoid brachytherapy plan versus intensity-modulated radiation therapy (IMRT boost plan for doses delivered to target volume and organs at risk (OAR in postoperative patients of cervical carcinoma following whole pelvic radiotherapy (WPRT. Materials and Methods: Fifteen postoperative patients of cervical carcinoma suitable for vaginal ovoid brachytherapy following WPRT of 46 Gy/23 fractions/4.5 weeks were included. All were treated with brachytherapy (two sessions of 8.5 Gy each. The equivalent dose for IMRT was calculated by computing biologically effective dose of brachytherapy by linear quadratic model. Dose of brachytherapy (two sessions of 8.5 Gy was equivalent to IMRT dose of 26 Gy/13 fractions. Doses to target volume and OAR were compared between HDR and IMRT plans. Results: Target volume was well covered with both HDR and IMRT plans, but dose with brachytherapy was much higher (P < 0.05. Mean doses, doses to 0.1, 1, 2, and 5cc, 1/3 rd , 1/2, and 2/3 rd volume of bladder and rectum were significantly lower with HDR plans. Conclusion: In postoperative patients of cervical carcinoma, HDR brachytherapy following WPRT appears to be better than IMRT for tumor coverage and reducing dose to critical organs.

  6. Poster - Thur Eve - 03: LDR to HDR: RADPOS applications in brachytherapy.

    Science.gov (United States)

    Cherpak, A J; Cygler, J E; Kertzscher, G; E, C; Perry, G

    2012-07-01

    The RADPOS in vivo dosimetry system combines an electromagnetic positioning sensor and either one or five MOSFET dosimeters. The feasibility of using the system for quality control has been explored for a range of radiotherapy treatment techniques including most recently transperineal interstitial permanent prostate brachytherapy and high dose rate (HDR) treatments. Dose and position information was collected by a RADPOS array detector inside a Foley catheter within patients' urethra during permanent seed implantation. Ten patients were studied, and average displacement during implantation was Δr = (1.4-5.1) mm, with movements up to 9.7 mm due to the removal of the transrectal ultrasound probe. Maximum integral dose in the prostatic urethra ranged from 110-195 Gy, and it was found that the dose can change up to 63 cGy (62.0%) depending on whether the rectal probe is in place. For HDR, a RADPOS detector was first calibrated with an Ir-192 source. A treatment was then simulated using a total of 50 dwell positions in 5 catheters in an acrylic phantom. Dwell positions ranged from 1 to 10 cm away from the RADPOS detector and dose was measured for each source position. An average calibration coefficient of 0.74±0.11 cGy/mV was calculated for the detector and the average absolute difference between measured values and expected dose was 0.7±5.4 cGy (5±20%). The demonstrated accuracy of RADPOS dose measurements along with its ability to simultaneously measure displacement makes it a powerful tool for brachytherapy treatments, where high dose gradients can present unique in vivo dosimetry challenges. © 2012 American Association of Physicists in Medicine.

  7. LDR vs. HDR brachytherapy for localized prostate cancer: the view from radiobiological models.

    Science.gov (United States)

    King, Christopher R

    2002-01-01

    Permanent LDR brachytherapy and temporary HDR brachytherapy are competitive techniques for clinically localized prostate radiotherapy. Although a randomized trial will likely never be conducted comparing these two forms of brachytherapy, a comparative radiobiological modeling analysis proves useful in understanding some of their intrinsic differences, several of which could be exploited to improve outcomes. Radiobiological models based upon the linear quadratic equations are presented for fractionated external beam, fractionated (192)Ir HDR brachytherapy, and (125)I and (103)Pd LDR brachytherapy. These models incorporate the dose heterogeneities present in brachytherapy based upon patient-derived dose volume histograms (DVH) as well as tumor doubling times and repair kinetics. Radiobiological parameters are normalized to correspond to three accepted clinical risk factors based upon T-stage, PSA, and Gleason score to compare models with clinical series. Tumor control probabilities (TCP) for LDR and HDR brachytherapy (as monotherapy or combined with external beam) are compared with clinical bNED survival rates. Predictions are made for dose escalation with HDR brachytherapy regimens. Model predictions for dose escalation with external beam agree with clinical data and validate the models and their underlying assumptions. Both LDR and HDR brachytherapy achieve superior tumor control when compared with external beam at conventional doses (LDR brachytherapy as boost achieves superior tumor control than when used as monotherapy. Stage for stage, both LDR and current HDR regimens achieve similar tumor control rates, in agreement with current clinical data. HDR monotherapy with large-dose fraction sizes might achieve superior tumor control compared with LDR, especially if prostate cancer possesses a high sensitivity to dose fractionation (i.e., if the alpha/beta ratio is low). Radiobiological models support the current clinical evidence for equivalent outcomes in localized

  8. Source position verification and dosimetry in HDR brachytherapy using an EPID

    International Nuclear Information System (INIS)

    Smith, R. L.; Taylor, M. L.; McDermott, L. N.; Franich, R. D.; Haworth, A.; Millar, J. L.

    2013-01-01

    Purpose: Accurate treatment delivery in high dose rate (HDR) brachytherapy requires correct source dwell positions and dwell times to be administered relative to each other and to the surrounding anatomy. Treatment delivery inaccuracies predominantly occur for two reasons: (i) anatomical movement or (ii) as a result of human errors that are usually related to incorrect implementation of the planned treatment. Electronic portal imaging devices (EPIDs) were originally developed for patient position verification in external beam radiotherapy and their application has been extended to provide dosimetric information. The authors have characterized the response of an EPID for use with an 192 Ir brachytherapy source to demonstrate its use as a verification device, providing both source position and dosimetric information.Methods: Characterization of the EPID response using an 192 Ir brachytherapy source included investigations of reproducibility, linearity with dose rate, photon energy dependence, and charge build-up effects associated with exposure time and image acquisition time. Source position resolution in three dimensions was determined. To illustrate treatment verification, a simple treatment plan was delivered to a phantom and the measured EPID dose distribution compared with the planned dose.Results: The mean absolute source position error in the plane parallel to the EPID, for dwells measured at 50, 100, and 150 mm source to detector distances (SDD), was determined to be 0.26 mm. The resolution of the z coordinate (perpendicular distance from detector plane) is SDD dependent with 95% confidence intervals of ±0.1, ±0.5, and ±2.0 mm at SDDs of 50, 100, and 150 mm, respectively. The response of the EPID is highly linear to dose rate. The EPID exhibits an over-response to low energy incident photons and this nonlinearity is incorporated into the dose calibration procedure. A distance (spectral) dependent dose rate calibration procedure has been developed. The

  9. 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

  10. Mathematical simulation of biologically equivalent doses for LDR-HDR

    International Nuclear Information System (INIS)

    Slosarek, K.; Zajusz, A.

    1996-01-01

    Based on the LQ model examples of biologically equivalent doses LDR, HDR and external beams were calculated. The biologically equivalent doses for LDR were calculated by appending to the LQ model the corrector for the time of repair of radiation sublethal damages. For radiation continuously delivered at a low dose rate the influence of sublethal damage repair time changes on biologically equivalent doses were analysed. For fractionated treatment with high dose rate the biologically equivalent doses were calculated by adding to the LQ model the formula of accelerated repopulation. For total biologically equivalent dose calculation for combine LDR-HDR-Tele irradiation examples are presented with the use of different parameters of the time of repair of sublethal damages and accelerated repopulation. The calculations performed show, that the same biologically equivalent doses can be obtained for different parameters of cell kinetics changes during radiation treatment. It also shows, that during biologically equivalent dose calculations for different radiotherapy schedules, ignorance of cell kinetics parameters can lead to relevant errors

  11. Radiotherapy physics

    International Nuclear Information System (INIS)

    Chen, G.T.Y.; Collier, J.M.; Lyman, J.T.; Pitluck, S.

    1982-01-01

    The Radiotherapy Physics Group works on the physical and biophysical aspects of charged particle radiotherapy. Our activities include the development of isosurvival beams (beams of uniform biological effect), computerized treatment planning development for charged particle radiotherapy, design of compensation to shape dose distributions, and development of dosimetry techniques to verify planned irradiations in both phantoms and patients

  12. Factors affecting the local control of stereotactic body radiotherapy for lung tumors including primary lung cancer and metastatic lung tumors

    International Nuclear Information System (INIS)

    Hamamoto, Yasushi; Kataoka, Masaaki; Yamashita, Motohiro

    2012-01-01

    The purpose of this study was to identify factors affecting local control of stereotactic body radiotherapy (SBRT) for lung tumors including primary lung cancer and metastatic lung tumors. Between June 2006 and June 2009, 159 lung tumors in 144 patients (primary lung cancer, 128; metastatic lung tumor, 31) were treated with SBRT with 48-60 Gy (mean 50.1 Gy) in 4-5 fractions. Higher doses were given to larger tumors and metastatic tumors in principle. Assessed factors were age, gender, tumor origin (primary vs. metastatic), histological subtype, tumor size, tumor appearance (solid vs. ground glass opacity), maximum standardized uptake value of positron emission tomography using 18 F-fluoro-2-deoxy-D-glucose, and SBRT doses. Follow-up time was 1-60 months (median 18 months). The 1-, 2-, and 3-year local failure-free rates of all lesions were 90, 80, and 77%, respectively. On univariate analysis, metastatic tumors (p<0.0001), solid tumors (p=0.0246), and higher SBRT doses (p=0.0334) were the statistically significant unfavorable factors for local control. On multivariate analysis, only tumor origin was statistically significant (p=0.0027). The 2-year local failure-free rates of primary lung cancer and metastatic lung tumors were 87 and 50%, respectively. A metastatic tumor was the only independently significant unfavorable factor for local control after SBRT. (author)

  13. 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

  14. HDR-Aggregate Read Service (ARS)

    Data.gov (United States)

    Department of Veterans Affairs — ARS is a SOAP web service exposed over HTTPS that provides an aggregated (report) view of HTH Survey, DMP and Census data stored in the HDR DB. ARS is deployed in...

  15. HDR-Clinical Data Service (CDS)

    Data.gov (United States)

    Department of Veterans Affairs — CDS is a SOAP/REST web service interface that supports Create, Retrieve, Update, and Delete (CRUD) operations against HDR data stores over secure Hypertext Transfer...

  16. The revision of RP 91 on criteria for acceptability of radiological (including radiotherapy) and nuclear medicine installations

    International Nuclear Information System (INIS)

    Faulkner, K.; Malone, J. F.; Christofides, S.; Lillicrap, S.; Horton, P.

    2013-01-01

    In 1997 the European Commission published Radiation Protection 91: 'Criteria for acceptability of radiological (including radiotherapy) and nuclear medicine installations'(1). This document specified the minimum criteria for acceptability. It has been used to this effect in legislation, codes of practice and by individual professionals. In a single document, it defined a level of performance at which remedial action was required. The document specified a series of parameters which characterised equipment performance and acceptable levels of performance. In its time it proved to be a useful document which was applied in member states to various degrees. Since the publication of Report 91 in 1997(1), a series of weaknesses emerged over time. Development of new radiological systems and technologies, as well as improvements in traditional technologies, has created circumstances where the acceptability criteria were in need of review. These weaknesses were recognised by the European Commission and a tender for its revision was issued. The criteria were developed by a team drawn from a broad range of backgrounds including hospitals, industry, government bodies, regulators and standardisation organisations. Representatives were mainly from Europe, but individuals from the American Association of Physicists in Medicine and International Atomic Energy Agency were included in the drafting process. This study describes the process employed in developing the revised document and the consultation process involved. One of the major difficulties the revision team encountered was related to an understanding of the actual meaning of the EC Directive(2). The view taken by the revision team was that Article 8, paragraph 3 places responsibilities on both the holders of radiological equipment and competent authorities. The acceptability criteria have been produced consistent with the European Commission's Medical Exposures Directive(2), which requires that patient exposures are

  17. Investigation of superstructure damping identification for the HDR containment building

    International Nuclear Information System (INIS)

    Hsieh, B.J.; Kot, C.A.; Srinivasan, M.G.

    1985-01-01

    A method for the estimation of first mode structural damping, developed by other investigators, was applied to shaker test data of the HDR containment building. Due to inadequate precision in the experimental phase measurements no valid results could be obtained. Based on modal analysis it was also noted that for systems such as the HDR building, contributions of higher modes are not negligible as was assumed in the original approach. Therefore, the procedure for the determination of superstructure damping using experimental data was extended to include the effects of higher modes. The extended method does not lead to any higher order nonlinear equations than the first mode approximation and was found to be as simple to apply as the original approach

  18. The Benefits of Including Clinical Factors in Rectal Normal Tissue Complication Probability Modeling After Radiotherapy for Prostate Cancer

    International Nuclear Information System (INIS)

    Defraene, Gilles; Van den Bergh, Laura; Al-Mamgani, Abrahim; Haustermans, Karin; Heemsbergen, Wilma; Van den Heuvel, Frank; Lebesque, Joos V.

    2012-01-01

    Purpose: To study the impact of clinical predisposing factors on rectal normal tissue complication probability modeling using the updated results of the Dutch prostate dose-escalation trial. Methods and Materials: Toxicity data of 512 patients (conformally treated to 68 Gy [n = 284] and 78 Gy [n = 228]) with complete follow-up at 3 years after radiotherapy were studied. Scored end points were rectal bleeding, high stool frequency, and fecal incontinence. Two traditional dose-based models (Lyman-Kutcher-Burman (LKB) and Relative Seriality (RS) and a logistic model were fitted using a maximum likelihood approach. Furthermore, these model fits were improved by including the most significant clinical factors. The area under the receiver operating characteristic curve (AUC) was used to compare the discriminating ability of all fits. Results: Including clinical factors significantly increased the predictive power of the models for all end points. In the optimal LKB, RS, and logistic models for rectal bleeding and fecal incontinence, the first significant (p = 0.011–0.013) clinical factor was “previous abdominal surgery.” As second significant (p = 0.012–0.016) factor, “cardiac history” was included in all three rectal bleeding fits, whereas including “diabetes” was significant (p = 0.039–0.048) in fecal incontinence modeling but only in the LKB and logistic models. High stool frequency fits only benefitted significantly (p = 0.003–0.006) from the inclusion of the baseline toxicity score. For all models rectal bleeding fits had the highest AUC (0.77) where it was 0.63 and 0.68 for high stool frequency and fecal incontinence, respectively. LKB and logistic model fits resulted in similar values for the volume parameter. The steepness parameter was somewhat higher in the logistic model, also resulting in a slightly lower D 50 . Anal wall DVHs were used for fecal incontinence, whereas anorectal wall dose best described the other two endpoints. Conclusions

  19. The Benefits of Including Clinical Factors in Rectal Normal Tissue Complication Probability Modeling After Radiotherapy for Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Defraene, Gilles, E-mail: gilles.defraene@uzleuven.be [Radiation Oncology Department, University Hospitals Leuven, Leuven (Belgium); Van den Bergh, Laura [Radiation Oncology Department, University Hospitals Leuven, Leuven (Belgium); Al-Mamgani, Abrahim [Department of Radiation Oncology, Erasmus Medical Center - Daniel den Hoed Cancer Center, Rotterdam (Netherlands); Haustermans, Karin [Radiation Oncology Department, University Hospitals Leuven, Leuven (Belgium); Heemsbergen, Wilma [Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital, Amsterdam (Netherlands); Van den Heuvel, Frank [Radiation Oncology Department, University Hospitals Leuven, Leuven (Belgium); Lebesque, Joos V. [Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital, Amsterdam (Netherlands)

    2012-03-01

    Purpose: To study the impact of clinical predisposing factors on rectal normal tissue complication probability modeling using the updated results of the Dutch prostate dose-escalation trial. Methods and Materials: Toxicity data of 512 patients (conformally treated to 68 Gy [n = 284] and 78 Gy [n = 228]) with complete follow-up at 3 years after radiotherapy were studied. Scored end points were rectal bleeding, high stool frequency, and fecal incontinence. Two traditional dose-based models (Lyman-Kutcher-Burman (LKB) and Relative Seriality (RS) and a logistic model were fitted using a maximum likelihood approach. Furthermore, these model fits were improved by including the most significant clinical factors. The area under the receiver operating characteristic curve (AUC) was used to compare the discriminating ability of all fits. Results: Including clinical factors significantly increased the predictive power of the models for all end points. In the optimal LKB, RS, and logistic models for rectal bleeding and fecal incontinence, the first significant (p = 0.011-0.013) clinical factor was 'previous abdominal surgery.' As second significant (p = 0.012-0.016) factor, 'cardiac history' was included in all three rectal bleeding fits, whereas including 'diabetes' was significant (p = 0.039-0.048) in fecal incontinence modeling but only in the LKB and logistic models. High stool frequency fits only benefitted significantly (p = 0.003-0.006) from the inclusion of the baseline toxicity score. For all models rectal bleeding fits had the highest AUC (0.77) where it was 0.63 and 0.68 for high stool frequency and fecal incontinence, respectively. LKB and logistic model fits resulted in similar values for the volume parameter. The steepness parameter was somewhat higher in the logistic model, also resulting in a slightly lower D{sub 50}. Anal wall DVHs were used for fecal incontinence, whereas anorectal wall dose best described the other two endpoints

  20. Difference in target definition using three different methods to include respiratory motion in radiotherapy of lung cancer.

    Science.gov (United States)

    Sloth Møller, Ditte; Knap, Marianne Marquard; Nyeng, Tine Bisballe; Khalil, Azza Ahmed; Holt, Marianne Ingerslev; Kandi, Maria; Hoffmann, Lone

    2017-11-01

    Minimizing the planning target volume (PTV) while ensuring sufficient target coverage during the entire respiratory cycle is essential for free-breathing radiotherapy of lung cancer. Different methods are used to incorporate the respiratory motion into the PTV. Fifteen patients were analyzed. Respiration can be included in the target delineation process creating a respiratory GTV, denoted iGTV. Alternatively, the respiratory amplitude (A) can be measured based on the 4D-CT and A can be incorporated in the margin expansion. The GTV expanded by A yielded GTV + resp, which was compared to iGTV in terms of overlap. Three methods for PTV generation were compared. PTV del (delineated iGTV expanded to CTV plus PTV margin), PTV σ (GTV expanded to CTV and A was included as a random uncertainty in the CTV to PTV margin) and PTV ∑ (GTV expanded to CTV, succeeded by CTV linear expansion by A to CTV + resp, which was finally expanded to PTV ∑ ). Deformation of tumor and lymph nodes during respiration resulted in volume changes between the respiratory phases. The overlap between iGTV and GTV + resp showed that on average 7% of iGTV was outside the GTV + resp implying that GTV + resp did not capture the tumor during the full deformable respiration cycle. A comparison of the PTV volumes showed that PTV σ was smallest and PTV Σ largest for all patients. PTV σ was in mean 14% (31 cm 3 ) smaller than PTV del , while PTV del was 7% (20 cm 3 ) smaller than PTV Σ . PTV σ yields the smallest volumes but does not ensure coverage of tumor during the full respiratory motion due to tumor deformation. Incorporating the respiratory motion in the delineation (PTV del ) takes into account the entire respiratory cycle including deformation, but at the cost, however, of larger treatment volumes. PTV Σ should not be used, since it incorporates the disadvantages of both PTV del and PTV σ .

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

    Energy Technology Data Exchange (ETDEWEB)

    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. Olfactory neuroblastoma: the long-term outcome and late toxicity of multimodal therapy including radiotherapy based on treatment planning using computed tomography

    International Nuclear Information System (INIS)

    Mori, Takashi; Onimaru, Rikiya; Onodera, Shunsuke; Tsuchiya, Kazuhiko; Yasuda, Koichi; Hatakeyama, Hiromitsu; Kobayashi, Hiroyuki; Terasaka, Shunsuke; Homma, Akihiro; Shirato, Hiroki

    2015-01-01

    Olfactory neuroblastoma (ONB) is a rare tumor originating from olfactory epithelium. Here we retrospectively analyzed the long-term treatment outcomes and toxicity of radiotherapy for ONB patients for whom computed tomography (CT) and three-dimensional treatment planning was conducted to reappraise the role of radiotherapy in the light of recent advanced technology and chemotherapy. Seventeen patients with ONB treated between July 1992 and June 2013 were included. Three patients were Kadish stage B and 14 were stage C. All patients were treated with radiotherapy with or without surgery or chemotherapy. The radiation dose was distributed from 50 Gy to 66 Gy except for one patient who received 40 Gy preoperatively. The median follow-up time was 95 months (range 8–173 months). The 5-year overall survival (OS) and relapse-free survival (RFS) rates were estimated at 88% and 74%, respectively. Five patients with stage C disease had recurrence with the median time to recurrence of 59 months (range 7–115 months). Late adverse events equal to or above Grade 2 in CTCAE v4.03 were observed in three patients. Multimodal therapy including radiotherapy with precise treatment planning based on CT simulation achieved an excellent local control rate with acceptable toxicity and reasonable overall survival for patients with ONB

  3. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Xiaofeng, E-mail: xyang43@emory.edu; Rossi, Peter; Ogunleye, Tomi; Marcus, David M.; Jani, Ashesh B.; Curran, Walter J.; Liu, Tian [Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, Georgia 30322 (United States); Mao, Hui [Department of Radiology and Imaging Sciences, Emory University, Atlanta, Georgia 30322 (United States)

    2014-11-01

    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

  5. Traceable calibration of hospital 192Ir HDR sources

    International Nuclear Information System (INIS)

    Govinda Rajan, K.N.; Bhatt, B.C.; Pendse, A.M.; Kannan, V.

    2002-01-01

    Presently, no primary standard exists for the standardization of remote afterloading 192 Ir HDR sources. These sources are, therefore, being standardized by a few Secondary Standard Dosimetry Laboratories (SSDLs), in terms of Air Kerma Strength (AKS) or Reference Air Kerma Rate (RAKR) using a 0.6 cc Farmer type chamber, set up as an Interim Standard. These SSDLs offer calibration to well type of ionization chambers that are normally used by the hospitals for calibrating the 192 lr HDR source. Presently, in many countries, including India, well chambers are not commercially available. Nor do these countries offer any calibration service for 192 lr HDR source. With the result users make use of well chambers imported from different countries with their calibration traceable to the country of origin. Since no intercomparisons between these countries have been reported, the measurement consistency between hospitals becomes questionable. The problem is compounded by the fact that these chambers are used for several years without re-calibration since no calibration service is locally available. For instance, in India, the chambers have been in use in hospitals, since 1994, without a second calibration. Not all hospitals use the well chamber for the calibration of the 192 lr HDR source. Many hospitals make use of 0.6 cc chambers, in air, at short source to chamber distances, for measuring the AKS of the source. The latter method is prone to much larger inaccuracy due to the use of very short source to chamber distances without proper calibration jigs, use of 60 Co calibration factor for 192 Ir HDR source calibrations, neglecting correction factors for room scatter, fluence non-uniformity, use of arbitrary buildup factors for the buildup cap of the chamber etc. A comparison of the procedures used at hospitals revealed that various arbitrary methods are in use at hospitals. An indigenously developed well chamber was calibrated against a Reference Standard traceable to the

  6. A national survey of HDR source knowledge among practicing radiation oncologists and residents: Establishing a willingness-to-pay threshold for cobalt-60 usage.

    Science.gov (United States)

    Mailhot Vega, Raymond; Talcott, Wesley; Ishaq, Omar; Cohen, Patrice; Small, Christina J; Duckworth, Tamara; Sarria Bardales, Gustavo; Perez, Carmen A; Schiff, Peter B; Small, William; Harkenrider, Matthew M

    Ir-192 is the predominant source for high-dose-rate (HDR) brachytherapy in United States markets. Co-60, with longer half-life and fewer source exchanges, has piloted abroad with comparable clinical dosimetry but increased shielding requirements. We sought to identify practitioner knowledge of Co-60 and establish acceptable willingness-to-pay (WTP) thresholds for additional shielding requirements for use in future cost-benefit analysis. A nationwide survey of U.S. radiation oncologists was conducted from June to July 2015, assessing knowledge of HDR sources, brachytherapy unit shielding, and factors that may influence source-selection decision-making. Self-identified decision makers in radiotherapy equipment purchase and acquisition were asked their WTP on shielding should a more cost-effective source become available. Four hundred forty surveys were completed and included. Forty-four percent were ABS members. Twenty percent of respondents identified Co-60 as an HDR source. Respondents who identified Co-60 were significantly more likely to be ABS members, have attended a national brachytherapy conference, and be involved in brachytherapy selection. Sixty-six percent of self-identified decision makers stated that their facility would switch to a more cost-effective source than Ir-192, if available. Cost and experience were the most common reasons provided for not switching. The most common WTP value selected by respondents was decision makers to establish WTP for shielding costs that source change to Co-60 may require. These results will be used to establish WTP threshold for future cost-benefit analysis. Copyright © 2017 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  7. Nasopharyngeal Carcinoma Treated with Precision-Oriented Radiation Therapy Techniques Including Intensity-Modulated Radiotherapy: Preliminary Results

    Directory of Open Access Journals (Sweden)

    Wen-Shan Liu

    2004-02-01

    Full Text Available This paper reports preliminary results with intensity-modulated radiotherapy (IMRT in nasopharyngeal carcinoma (NPC. Between August 2000 and May 2001, we treated 19 patients with NPC using IMRT. Twelve patients had stage I-II disease and seven had stage III-IV disease. Six patients received 9.0-19.8 Gy three-dimensional conformal radiotherapy (3D-CRT before IMRT and 18 patients received a brachytherapy boost after IMRT. The mean follow-up time was 13.0 months. All patients with stage II-IV disease except one received two cycles of chemoradiotherapy with cisplatin and 5-fluorouracil (5-FU during radiotherapy, followed by two to four cycles of chemotherapy after radiotherapy. Tumor response was assessed using clinical examination and computerized tomography or magnetic resonance imaging. The mean doses administered to the gross tumor volume and clinical tumor volume were 70.9 Gy and 63.2 Gy, respectively. The mean doses administered to the right and left parotid glands were 38.1 Gy and 38.6 Gy, respectively. All 19 patients had a complete response of primary and lymph node disease. Grade III mucositis developed during chemoradiotherapy in 15 patients (79%. In addition, clinical grade I xerostomia was recorded in nine patients, grade II in nine, and grade III in one. This study demonstrated that 3D-CRT, IMRT, intracavitary brachytherapy, and chemotherapy are effective and safe methods to treat NPC. Although IMRT treatment spared parotid gland function, its efficacy may be significantly influenced by disease stage and location of the neck lymph nodes. More cases and a longer follow-up to assess survival and complications are planned.

  8. Interstitial prostate brachytherapy. LDR-PDR-HDR

    International Nuclear Information System (INIS)

    Kovacs, Gyoergy; Hoskin, Peter

    2013-01-01

    The first comprehensive overview of interstitial brachytherapy for the management of local or locally advanced prostate cancer. Written by an interdisciplinary team who have been responsible for the successful GEC-ESTRO/EAU Teaching Course. Discusses in detail patient selection, the results of different methods, the role of imaging, and medical physics issues. Prostate brachytherapy has been the subject of heated debate among surgeons and the proponents of the various brachytherapy methods. This very first interdisciplinary book on the subject provides a comprehensive overview of innovations in low dose rate (LDR), high dose rate (HDR), and pulsed dose rate (PDR) interstitial brachytherapy for the management of local or locally advanced prostate cancer. In addition to detailed chapters on patient selection and the use of imaging in diagnostics, treatment guidance, and implantation control, background chapters are included on related medical physics issues such as treatment planning and quality assurance. The results obtained with the different treatment options and the difficult task of salvage treatment are fully discussed. All chapters have been written by internationally recognized experts in their fields who for more than a decade have formed the teaching staff responsible for the successful GEC-ESTRO/EAU Prostate Brachytherapy Teaching Course. This book will be invaluable in informing residents and others of the scientific background and potential of modern prostate brachytherapy. It will also prove a useful source of up-to-date information for those who specialize in prostate brachytherapy or intend to start an interstitial brachytherapy service.

  9. Preliminary results of a phase I/II study of HDR brachytherapy alone for T1/T2 breast cancer

    International Nuclear Information System (INIS)

    Wazer, David E.; Berle, Lisa; Graham, Roger; Chung, Maureen; Rothschild, Janice; Graves, Theresa; Cady, Blake; Ulin, Kenneth; Ruthazer, Robin; DiPetrillo, Thomas A.

    2002-01-01

    Purpose: To investigate the feasibility, toxicity, cosmetic outcome, and local control of high-dose-rate (HDR) brachytherapy alone without whole breast external beam irradiation for early-stage breast carcinoma. Methods and Materials: Between June 1997 and August 1999, 32 women diagnosed with a total of 33 AJCC Stage I/II breast carcinomas underwent surgical breast excision and postoperative irradiation using HDR brachytherapy interstitial implantation as part of a multi-institutional clinical Phase I/II protocol. Eligible patients included those with T1, T2, N0, N1 (≤3 nodes positive), and M0 tumors of nonlobular histologic features with negative surgical margins, no extracapsular lymph node extension, and a negative postexcision mammogram. Brachytherapy catheters were placed at the initial excision, reexcision, or either sentinel or full-axillary sampling. Direct visualization, surgical clips, and ultrasound and/or CT scan assisted in the delineation of the target volume, defined as the excision cavity plus a 2-cm margin. High-activity 192 Ir (3-10 Ci) was used to deliver 340 cGy/fraction, 2 fractions/d, for 5 consecutive days, to a total dose of 34 Gy to the target volume. Source position and dwell times were calculated using standard volume optimization techniques. Results: The median follow-up of all patients was 33 months, and the mean patient age was 63 years. The mean tumor size was 1.3 cm, and 55% had an extensive intraductal component. Three patients had positive axillary nodes. Two patients experienced moderate perioperative pain that required narcotic analgesics. No peri- or postoperative infections occurred. No wound healing problems and no significant skin reactions related to the implant developed. The Radiation Therapy Oncology Group late radiation morbidity scoring scheme was applied to the entire 33-case cohort. In the assessment of the skin, 30 cases were Grade 0-1 and 3 cases were Grade 2. Subcutaneous toxicity was scored as 11 patients with

  10. Evaluation of a HDR image sensor with logarithmic response for mobile video-based applications

    Science.gov (United States)

    Tektonidis, Marco; Pietrzak, Mateusz; Monnin, David

    2017-10-01

    The performance of mobile video-based applications using conventional LDR (Low Dynamic Range) image sensors highly depends on the illumination conditions. As an alternative, HDR (High Dynamic Range) image sensors with logarithmic response are capable to acquire illumination-invariant HDR images in a single shot. We have implemented a complete image processing framework for a HDR sensor, including preprocessing methods (nonuniformity correction (NUC), cross-talk correction (CTC), and demosaicing) as well as tone mapping (TM). We have evaluated the HDR sensor for video-based applications w.r.t. the display of images and w.r.t. image analysis techniques. Regarding the display we have investigated the image intensity statistics over time, and regarding image analysis we assessed the number of feature correspondences between consecutive frames of temporal image sequences. For the evaluation we used HDR image data recorded from a vehicle on outdoor or combined outdoor/indoor itineraries, and we performed a comparison with corresponding conventional LDR image data.

  11. Whither radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Ross, W M

    1987-03-01

    The 1986 Glyn Evans Memorial Lecture, given at the Joint Provincial Meeting of the Royal College of Radiologists, Sheffield, September 1986, sketches an outline of the history of radiotherapy and discusses the future development of the art. Topics included are siting of centres, training needs, the relationship of radiotherapy to other medical specialities, and the advantages and disadvantages of radiotherapy practitioners forming a separate medical College. (U.K.)

  12. Cardiovascular radiotherapy. A multi-disciplinary textbook. 2. rev. and enl. ed.

    International Nuclear Information System (INIS)

    Hehrlein, C.

    2002-01-01

    Cardiovascular radiotherapy has made rapid progress over the past few years, thus necessitating a revision and re-edition of this textbook. The structure of the first edition has been largely retained, but there have nevertheless been some important new additions, including chapters on ''New insights on vessel thrombosis and the edge effect following vascular brachytherapy'', ''Catheter-based intracoronary brachytherapy using the β emitter phosphorus 32'', ''Intracoronary afterloading using the Novoste trademark system'' and ''Catheter-based γ-HDR brachytherapy of the peripheral vessels''. The contributions contained in the first edition have also been thoroughly revised

  13. Development of a TLD mailed system for remote dosimetry audit for 192Ir HDR and PDR sources

    International Nuclear Information System (INIS)

    Roue, Amelie; Venselaar, Jack L.M.; Ferreira, Ivaldo H.; Bridier, Andre; Dam, Jan van

    2007-01-01

    Background and purpose: In the framework of an ESTRO ESQUIRE project, the BRAPHYQS Physics Network and the EQUAL-ESTRO laboratory have developed a procedure for checking the absorbed dose to water in the vicinity of HDR or PDR sources using a mailed TLD system. The methodology and the materials used in the procedure are based on the existing EQUAL-ESTRO external radiotherapy dose checks. Materials and methods: A phantom for TLD postal dose assurance service, adapted to accept catheters from different HDR afterloaders, has been developed. The phantom consists of three PMMA tubes supporting catheters placed at 120 degrees around a central TLD holder. A study on the use of LiF powder type DTL 937 (Philitech) has been performed in order to establish the TLD calibration in dose-to-water at a given distance from 192 Ir source, as well as to determine all correction factors to convert the TLD reading into absorbed dose to water. The dosimetric audit is based on the comparison between the dose to water measured with the TL dosimeter and the dose calculated by the clinical TPS. Results of the audits are classified in four different levels depending on the ratio of the measured dose to the stated dose. The total uncertainty budget in the measurement of the absorbed dose to water using TLD near an 192 Ir HDR source, including TLD reading, correction factors and TLD calibration coefficient, is determined as 3.27% (1 s). Results: To validate the procedures, the external audit was first tested among the members of the BRAPHYQS Network. Since November 2004, the test has been made available for use by all European brachytherapy centres. To date, 11 centres have participated in the checks and the results obtained are very encouraging. Nevertheless, one error detected has shown the usefulness of this audit. Conclusion: A method of absorbed dose to water determination in the vicinity of an 192 Ir brachytherapy source was developed for the purpose of a mailed TL dosimetry system. The

  14. Development of a TLD mailed system for remote dosimetry audit for (192)Ir HDR and PDR sources.

    Science.gov (United States)

    Roué, Amélie; Venselaar, Jack L M; Ferreira, Ivaldo H; Bridier, André; Van Dam, Jan

    2007-04-01

    In the framework of an ESTRO ESQUIRE project, the BRAPHYQS Physics Network and the EQUAL-ESTRO laboratory have developed a procedure for checking the absorbed dose to water in the vicinity of HDR or PDR sources using a mailed TLD system. The methodology and the materials used in the procedure are based on the existing EQUAL-ESTRO external radiotherapy dose checks. A phantom for TLD postal dose assurance service, adapted to accept catheters from different HDR afterloaders, has been developed. The phantom consists of three PMMA tubes supporting catheters placed at 120 degrees around a central TLD holder. A study on the use of LiF powder type DTL 937 (Philitech) has been performed in order to establish the TLD calibration in dose-to-water at a given distance from (192)Ir source, as well as to determine all correction factors to convert the TLD reading into absorbed dose to water. The dosimetric audit is based on the comparison between the dose to water measured with the TL dosimeter and the dose calculated by the clinical TPS. Results of the audits are classified in four different levels depending on the ratio of the measured dose to the stated dose. The total uncertainty budget in the measurement of the absorbed dose to water using TLD near an (192)Ir HDR source, including TLD reading, correction factors and TLD calibration coefficient, is determined as 3.27% (1s). To validate the procedures, the external audit was first tested among the members of the BRAPHYQS Network. Since November 2004, the test has been made available for use by all European brachytherapy centres. To date, 11 centres have participated in the checks and the results obtained are very encouraging. Nevertheless, one error detected has shown the usefulness of this audit. A method of absorbed dose to water determination in the vicinity of an (192)Ir brachytherapy source was developed for the purpose of a mailed TL dosimetry system. The accuracy of the procedure was determined. This method allows a

  15. Dosimetry experience of 192IR sources used In HDR brachytherapy for cervical cancer

    International Nuclear Information System (INIS)

    Daci, Lulzime; Myrku, Rodina Cela

    2013-01-01

    Purpose/Objective: The 192IR Sources are the most commonly used in radiotherapy treatments HDR worldwide. According to international recommendations on quality assurance in HDR brachytherapy, an acceptance test based on the determination of the source strength of any new source shall be carried out before first application to verify the manufacturer’s calibration data. The present paper gives the experimental determination of the source strength for our brachytherapy sources used until now in brachytherapy treatments. Materials/Methods: At Mother Teresa University Hospital we have a cost-effective gynecological brachytherapy unit from Eckert & Ziegler BEBIG named GyneSource® that is a five channel HDR after loader equipped with an 192IR source. The software used is HDR plus™ 2.5 that delivers an optimized treatment plan and makes the process especially fast and we use intracavitary BEBIG applicators. From April 2009 up to December 2012, we have imported nine HDR 192IR Sources. The exchange of the source and acceptance test is done by the physicist of the clinic once the source is imported. The measurements are done with a Well-type ionization chamber HDR1000 Plus and the electrometer used is MAX4000. Only seven sources are compared as we miss the dosimetry data of the first source, and the forth source was not measured and not used because the machine was not working in that time. Results/Conclusions: Eight sources were accepted for clinically use as the measurement were within the tolerance. The source number four with e deviation of -1.92% has been double checked compared with a free in-air measurement with farmer type chamber that gave a deviation to source certificate of 4% that is still inside the tolerance to accept a source for clinical use. The deviations of measured Air Kerma rate to the value of the sources certificates of all our used 192IR sources are less than 2%, which are within the tolerance. The checked value of updated source strength in

  16. Primary radiotherapy of stage IIA/B-IIIB cervical carcinoma. A comparison of continuous versus sequential regimens

    International Nuclear Information System (INIS)

    Mayer, A.; Nemeskeri, C.; Petnehazi, C.; Varga, S.; Naszaly, A.; Borgulya, G.

    2004-01-01

    Background: comprehensive literature on cervical cancer demonstrates, even today, the need for optimization of the timing of external-beam radiotherapy (EBRT) and high-dose-rate brachytherapy (HDR-BT) in the treatment of stage IIA/B-IIIB cervical carcinoma. Patients and methods: 210 patients with carcinoma of the cervix were treated in the Municipal Center of Oncoradiology between January 1991 and December 1996 (FIGO IIA: n = 10, FIGO IIB: n = 113, and FIGO IIIB: n = 87). Two regimens were compared: sequential radiation therapy (SRT) with 4 x 8 Gy HDR-BT to point A followed by EBRT, and continuous radiation therapy (CRT) in which 5 x 6 Gy HDR-BT to point A, one session per week, was integrated into the EBRT. A total dose of 68-70 Gy to point A and 52-54 Gy to point B was given in EBRT with SRT, five fractions per week were applied. Four fractions per week were applied in CRT, i.e., no EBRT was performed on the day of HDR-BT. Total doses to points A and B were identical in both regimens. Overall treatment time (OTT) amounted to 56 days for SRT and 35 days for CRT. Median follow-up time was 3.4 (2.5-4.2) years. Results: progression-free 5-year-survival (PFS) was 71% in the CRT and 56% in the SRT group. Nevertheless, this difference was not statistically significant (p = 1.00), and the same was found in a subgroup analysis of the different tumor stages, showing, however, an unequivocal trend. Late bladder and rectal injuries occurred in 13% and 25%, respectively. Late rectal injuries were significantly more frequent with SRT than CRT (35 patients in the SRT and 18 patients in the CRT group; p = 0.037). This was due to the higher doses per fraction of HDR-BT in the SRT group. No difference was found regarding late bladder injuries (p = 0.837). Conclusion: for the patients included in this study, no advantage has been found so far in using CRT, i.e., shortening the OTT by weekly integration of HDR-BT into EBRT. Nevertheless, an obvious trend exists. The dose of 8 Gy per

  17. Use of CT or MR dosimetry in high dose rate (HDR) brachytherapy for prostate cancer

    International Nuclear Information System (INIS)

    Liu, C.; Das, R.; See, A.; Duchesne, G.M.; Van Dyk, S.; Tai, K.H.

    2003-01-01

    Brachytherapy (BT) has, in recent years, become a well-utilised treatment option for prostate cancer. Tumour control probability relies on accurate dosimetry, which in turn relies on the accurate definition of the prostate gland. In external beam radiotherapy and BT, MRI has been shown to be a superior imaging modality when delineating the prostate gland especially at the apex. To date, data on MRI planning in prostate BT has focussed mainly on permanent interstitial implants. No data currently exists comparing MRI vs CT planning in HDR BT and its subsequent impact on prostate dosimetry. To determine the effects of MRI vs CT in HDR BT with respect to prostatic volumes and normal tissue doses, with the evaluations made using dose-volume histograms (DVH). Dosimetry parameters derived using CT and MRI (T2 weighted) scans of 11 patients who had received TRUS guided implants for HDR BT, were compared using the PlatoTM computer planning system. Treatment plans were generated on volumes marked by the same radiation oncologist for each patient. Comparison was made of the treatment plans (dosimetry) between: 1. CT generated plans; 2. CT generated plans assessed using MRI marked volumes and 3. MRI generated plans. We confirm the previously reported results that CT scans can overestimate prostatic volumes compared with MRI. Variations were noted in CT and MRI based plans that may allow improved sparing of the rectum and urethra when using MRI planning. The main disadvantages of using MRI scans are access to facilities as well as identifying a dummy source to adequately define the tips of our catheters. It is feasible to utilise MRI scans for HDR BT planning. The clearer definition of anatomical structures has added advantages when contouring the prostate

  18. Presumed atypical HDR syndrome associated with Band Keratopathy and pigmentary retinopathy.

    Science.gov (United States)

    Kim, Cinoo; Cheong, Hae Il; Kim, Jeong Hun; Yu, Young Suk; Kwon, Ji Won

    2011-01-01

    This report describes presumed atypical hypoparathyroidism, deafness, and renal dysplasia (HDR) syndrome associated with unexpected ocular findings. The patient had exotropia, bilateral band keratopathy, and pigmentary retinopathy, including attenuated retinal vessels and atrophy of the retinal pigment epithelium. Even though the calcific plaques were successfully removed, visual acuity in both eyes gradually decreased and electroretinography was extinguished. Copyright 2009, SLACK Incorporated.

  19. Guidelines for optimization of planar HDR implants

    International Nuclear Information System (INIS)

    Zwicker, R.D.; Schmidt-Ullrich, R.

    1996-01-01

    Purpose: Conventional low dose rate (LDR) planar Ir-192 implants are typically carried out using at most a few different source strengths. Remote afterloading offers a much higher degree of flexibility with individually programmable dwell times. Dedicated software is available to generate individual dwell times producing isodose surfaces which contour as closely as possible the target volume. The success of these algorithms in enclosing the target volume while sparing normal tissues is dependent on the positioning of the source guides which constrain the dwell points. In this work we provide source placement guidelines for optimal coverage and dose uniformity in planar high dose rate (HDR) implants. The resulting distributions are compared with LDR treatments in terms of dose uniformity and early and late tissue effects. Materials and methods: Computer studies were undertaken to determine source positions and dwell times for optimal dose uniformity in planar HDR implants, and the results were compared to those obtained using corresponding LDR implant geometries. The improvements in the dose distributions achieved with the remote after loader are expected to help offset the increased late tissue effects which can occur when LDR irradiation is replaced with a few large HDR fractions. Equivalent differential volume-dose (DVD) curves for early and late effects were calculated for different numbers of HDR fractions using a linear-quadratic model and compared to the corresponding curves for the LDR regime. Results: Tables of source placement parameters were generated as guidelines for achieving highly homogeneous planar HDR dose distributions. Differential volume-dose data generated inside the target volume provide a quantitative measure of the improvement in real dose homogeneity obtained with remote afterloading. The net result is a shift of the peak in the DVD curve toward lower doses relative to the LDR implant. The equivalent DVD curves for late effects obtained

  20. 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.

  1. 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.

  2. Quality assurance of HDR 192Ir sources using a Fricke dosimeter.

    Science.gov (United States)

    Austerlitz, C; Mota, H; Almeida, C E; Allison, R; Sibata, C

    2007-04-01

    A prototype of a Fricke dosimetry system consisting of a 15 x 15 x 15 cm3 water phantom made of Plexiglas and a 11.3-ml Pyrex balloon fitted with a 0.2 cm thick Pyrex sleeve in its center was created to assess source strength and treatment planning algorithms for use in high dose rate (HDR) 192Ir afterloading units. In routine operation, the radioactive source is positioned at the end of a sleeve, which coincides with the center of the spherical balloon that is filled with Fricke solution, so that the solution is nearly isotropically irradiated. The Fricke system was calibrated in terms of source strength against a reference well-type ionization chamber, and in terms of radial dose by means of an existing algorithm from the HDR's treatment planning system. Because the system is based on the Fricke dosimeter itself, for a given type and model of 192Ir source, the system needs initial calibration but no recalibration. The results from measurements made over a 10 month period, including source decay and source substitutions, have shown the feasibility of using such a system for quality control (QC) of HDR afterloading equipment, including both the source activity and treatment planning parameters. The benefit of a large scale production and the use of this device for clinical HDR QC audits via mail are also discussed.

  3. Anatomy-based inverse optimization in high-dose-rate brachytherapy combined with hypofractionated external beam radiotherapy for localized prostate cancer: Comparison of incidence of acute genitourinary toxicity between anatomy-based inverse optimization and geometric optimization

    International Nuclear Information System (INIS)

    Akimoto, Tetsuo; Katoh, Hiroyuki; Kitamoto, Yoshizumi; Shirai, Katsuyuki; Shioya, Mariko; Nakano, Takashi

    2006-01-01

    Purpose: To evaluate the advantages of anatomy-based inverse optimization (IO) in planning high-dose-rate (HDR) brachytherapy. Methods and Materials: A total of 114 patients who received HDR brachytherapy (9 Gy in two fractions) combined with hypofractionated external beam radiotherapy (EBRT) were analyzed. The dose distributions of HDR brachytherapy were optimized using geometric optimization (GO) in 70 patients and by anatomy-based IO in the remaining 44 patients. The correlation between the dose-volume histogram parameters, including the urethral dose and the incidence of acute genitourinary (GU) toxicity, was evaluated. Results: The averaged values of the percentage of volume receiving 80-150% of the prescribed minimal peripheral dose (V 8 -V 15 ) of the urethra generated by anatomy-based IO were significantly lower than the corresponding values generated by GO. Similarly, the averaged values of the minimal dose received by 5-50% of the target volume (D 5 -D 5 ) obtained using anatomy-based IO were significantly lower than those obtained using GO. Regarding acute toxicity, Grade 2 or worse acute GU toxicity developed in 23% of all patients, but was significantly lower in patients for whom anatomy-based IO (16%) was used than in those for whom GO was used (37%), consistent with the reduced urethral dose (p <0.01). Conclusion: The results of this study suggest that anatomy-based IO is superior to GO for dose optimization in HDR brachytherapy for prostate cancer

  4. Effect and toxicity of endoluminal high-dose-rate (HDR) brachytherapy in centrally located tumors of the upper respiratory tract

    International Nuclear Information System (INIS)

    Harms, W.; Wannenmacher, M.; Becker, H.; Herth, F.; Fritz, P.

    2000-01-01

    Aim: To assess effect an toxicity of high-dose-rate afterloading (HDR) alone or in combination with external beam radiotherapy (EBRT) in centrally located tumors of the upper respiratory tract. Patients and Methods: From 1987 to 1996, 55 patients were treated. Twenty-one patients (group A1: 17 non-small-cell lung cancer [NSCLC], A2: 4 metastases from other malignancies) were treated using HDR alone due to a relapse after external beam irradiation. In 34 previously untreated and inoperable patients (group B1: 27 NSCLC, B2: 7 metastases from other malignancies) HDR was given as a boost after EBRT (30 to 60 Gy, median 50). HDR was carried out with a 192 Ir source (370 GBq). The brachytherapy dose (group A: 5 to 27 Gy, median 20; B: 10 to 20 Gy, median 15) was prescribed to 1 cm distance from the source axis. A distanciable applicator was used in 39/55 patients. Results: In group A1, a response rate (CR, PR) of 53% (group B1: 77%) was reached. The median survival (Kaplan-Meier) was 5 months in group A1 (B1: 20 months). The 1-, 3- and 5-year local progression free survival rates (Kaplan-Meier) were 66% (15%), 52% (0%), and 37% (0%) in group B1 (group A1). Prognostic favorable factors in group B1 were a tumor diameter 70. Grade-1 or 2 toxicity (RTOG/EORTC) occurred in 0% in group A and in 6% in group B. We observed no Grad-3 or 4 toxicity. Complications caused by persistent or progressive local disease occurred in 3 patients in goup A (fatal hemorrhage, tracheomediastinal fistula, hemoptysis) and in 2 patients in group B (fatal hemorrhage, hemoptysis). Conclusions: HDR brachytherapy is an effective treatment with moderate side effects. In combination with external beam irradiation long-term remissions can be reached in one third of the patients. (orig.) [de

  5. 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.

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

    International Nuclear Information System (INIS)

    Chang, Z.

    2016-01-01

    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

  7. 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.

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

    International Nuclear Information System (INIS)

    Mourtada, F.

    2016-01-01

    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

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

    International Nuclear Information System (INIS)

    Zoberi, J.

    2016-01-01

    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

  10. 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.

  11. 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.

  12. Neodadjuvante und adjuvante Kurzzeit-Hormontherapie in Kombination mit konformaler HDR-Brachytherapie beim Prostatakarzinom

    Directory of Open Access Journals (Sweden)

    Martin T

    2004-01-01

    Full Text Available Zielsetzung: Auswertung der Behandlungsergebnisse der neoadjuvanten und adjuvanten Kurzzeit-Hormontherapie kombiniert mit konformaler HDR-Brachytherapie und externer Radiotherapie beim Prostatakarzinom. Patienten und Methoden: Von 01/97 bis 09/99 behandelten wir 102 Patienten mit Prostatakarzinomen im Stadium T1–3 N0 M0. Im Stadium T1–2 befanden sich 71, im Stadium T3 31 Patienten. Der mediane prätherapeutische PSA-Wert betrug 15,3 ng/ml. Nach ultraschallgesteuerter transrektaler Implantation von vier Afterloadingnadeln erfolgte die CT-gestützte 3D-Brachytherapie- Planung. Alle Patienten erhielten vier HDR-Implantate mit einer Referenzdosis von 5 Gy oder 7 Gy pro Implantat. Die Zeit zwischen jedem Implantat betrug jeweils 14 Tage. Nach der Brachytherapie folgte die externe Radiotherapie bis 39,6 Gy oder 45,0 Gy. Alle Patienten erhielten eine neoadjuvante und adjuvante Kurzzeit-Hormontherapie, die 2–19 Monate vor der Brachytherapie eingeleitet und 3 Monate nach Abschluß der externen Radiotherapie abgesetzt wurde (mediane Dauer: 9 Monate. Ergebnisse: Die mediane Nachbeobachtungszeit war 2,6 Jahre (range: 2,0–4,1 Jahre. Die biochemische Kontrollrate betrug 82 % nach 3 Jahren. Bei 14/102 Patienten registrierten wir ein biochemisches Rezidiv, bei 5/102 Patienten ein klinisches Rezidiv. Das Gesamtüberleben betrug 90 %, das krankheitsspezifische Überleben 98,0 % nach 3 Jahren. Ein Patient entwickelte eine prostato-urethro-rektale Fistel als späte Grad 4-Toxizität. Akute Grad-3 Toxizitäten traten bei 4 %, späte Grad-3 Toxizitäten bei 5 % der Patienten auf. Schlußfolgerung: Die neoadjuvante und adjuvante Kurzzeit-Hormontherapie kombiniert mit konformaler HDR-Brachytherapie und externer Radiotherapie erweist sich als sichere und wirksame Behandlungsmodalität beim Prostatakarzinom mit minimalen behandlungsbedingten Toxizitäten und einer vielversprechenden biochemischen Kontrollrate nach medianer Nachbeobachtungszeit von 2,6 Jahren.

  13. A review of the HDR research programme

    International Nuclear Information System (INIS)

    Talja, H.; Koski, K.; Rintamaa, R.; Keskinen, R.

    1995-10-01

    In the German HDR (Heissdampfreaktor, hot steam reactor) reactor safety programme, experiments and simulating numerical analyses have been undertaken since 1976 to study the integrity and safety of light water reactors under operational and faulted conditions. The last experiments of the programme were conducted in 1991. The post test analyses have been finished by March 1994 and the last final reports were obtained a few months later. The report aims to inform the utilities and the regulatory body of Finland about the contents of the lokset HDR research programme and to consider the applicability of the results to safety analyses of Finnish nuclear power plants. The report centers around the thermal shock and piping component experiments within the last or third phase of the HDR programme. Investigations into severe reactor accidents, fire safety and non-destructive testing, also conducted during the third phase, are not considered. The report presents a review of the following experiment groups: E21 (crack growth under corrosive conditions, loading due to thermal stratification), E22 (leak rate and leak detection experiments of through-cracked piping), E23 (thermal transient and stratification experiments for a pipe nozzle), E31 (vibration of cracked piping due to blow down and closure of isolation valve), E32 (seismically induced vibrations of cracked piping), E33 (condensation phenomena in horizontal piping during emergency cooling). A comprehensive list of reference reports, received by VTT and containing a VTT more detailed description, is given for each experiment group. The review is focused on the loading conditions and their theoretical modelling. A comparison of theoretical and experimental results is presented for each experiment group. The safety margins are finally assessed with special reference to leak-before-break, a well known principle for assuring the integrity of primary circuit piping of nuclear power plants. (orig.) (71 figs., 5 tabs.)

  14. HDR economy with special reference to conditions in Europe

    International Nuclear Information System (INIS)

    Smolka, K.; Kappelmeyer, O.

    1992-01-01

    A cost benefit model for the economic evaluation of HDR energy production cost was developed. It can be used for systematic cost analyses of different components of a HDR plant. This relates to natural subsurface conditions (i.e., geothermal gradient, tectonic stress) as well as technical components (i.e., boreholes, heat/power conversion system). The model provides the limiting conditions for an economic HDR energy production. The economic model was applied for an evaluation of the natural parameters in the subsurface of Germany regarding their HDR-suitability. Within a site selection program in Europe the model is part of feasibility studies for the conceptual design of a HDR demonstration plant at three candidate sites: Bad Urach (Germany); Soultz-sous-Forets (France) and Cornwall (UK)

  15. 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.

  16. Difference in target definition using three different methods to include respiratory motion in radiotherapy of lung cancer

    DEFF Research Database (Denmark)

    Sloth Møller, Ditte; Knap, Marianne Marquard; Nyeng, Tine Bisballe

    2017-01-01

    : PTVσ yields the smallest volumes but does not ensure coverage of tumor during the full respiratory motion due to tumor deformation. Incorporating the respiratory motion in the delineation (PTVdel) takes into account the entire respiratory cycle including deformation, but at the cost, however, of larger...

  17. Relocation of a nucletron microselectron-HDR brachytherapy system

    Energy Technology Data Exchange (ETDEWEB)

    Bartrum, T; Tran, T; Freeman, N; Morales, J [St Vincents Hospital, Darlinghurst, NSW (Australia)

    2004-12-15

    Full text: For a period of four weeks, our clinical Nucletron microSelectron high dose rate (HDR) brachytherapy system was pulled out of clinical use and relocated to a new building. During this period decommission tests, de-wiring of the treatment unit and its associated safety system (such as radiation detector, emergency off circuits and door interlocks), transportation of all equipment, re-wiring of this equipment in the new location and recommission tests were carried out. The decommission and recommission test program was designed upon consultation with the manufacturer's (Nucletron) acceptance test procedures and work carried out by others. The ACPSEM tolerances for remote afterloaders was used as a guideline. In addition to mandatory dosimetry, positional, workstation database and safety tests, two Australian Standard compliance tests were carried out. The compliance tests involved one for remote afterloaders and another for treatment room design. This testing program was designed and implemented with the aim of ensuring ongoing safe delivery of brachytherapy doses to the patient. The testing program consisted of two parts. The first involved a series of decommissioning tests that consisted of dosimetry tests such as source and check cable positional accuracy and source calibration tests. In addition to these tests an inventory of standard plans, patient records and system configuration information was catalogued. The second part involved a series of recommission tests and involved carrying out dosimetry tests on the brachytherapy system (positional accuracy and calibration tests), simulating common treatment scenarios (prostate, cervical, vaginal and bile duct) and checking standard plans; patient records and system configuration had remained unchanged. During this period, other tests were carried out. These included Nucletron acceptance and preventative maintenance tests, Australian Standards compliance testing and integrity of network transfer of

  18. Relocation of a nucletron microselectron-HDR brachytherapy system

    International Nuclear Information System (INIS)

    Bartrum, T.; Tran, T.; Freeman, N.; Morales, J.

    2004-01-01

    Full text: For a period of four weeks, our clinical Nucletron microSelectron high dose rate (HDR) brachytherapy system was pulled out of clinical use and relocated to a new building. During this period decommission tests, de-wiring of the treatment unit and its associated safety system (such as radiation detector, emergency off circuits and door interlocks), transportation of all equipment, re-wiring of this equipment in the new location and recommission tests were carried out. The decommission and recommission test program was designed upon consultation with the manufacturer's (Nucletron) acceptance test procedures and work carried out by others. The ACPSEM tolerances for remote afterloaders was used as a guideline. In addition to mandatory dosimetry, positional, workstation database and safety tests, two Australian Standard compliance tests were carried out. The compliance tests involved one for remote afterloaders and another for treatment room design. This testing program was designed and implemented with the aim of ensuring ongoing safe delivery of brachytherapy doses to the patient. The testing program consisted of two parts. The first involved a series of decommissioning tests that consisted of dosimetry tests such as source and check cable positional accuracy and source calibration tests. In addition to these tests an inventory of standard plans, patient records and system configuration information was catalogued. The second part involved a series of recommission tests and involved carrying out dosimetry tests on the brachytherapy system (positional accuracy and calibration tests), simulating common treatment scenarios (prostate, cervical, vaginal and bile duct) and checking standard plans; patient records and system configuration had remained unchanged. During this period, other tests were carried out. These included Nucletron acceptance and preventative maintenance tests, Australian Standards compliance testing and integrity of network transfer of

  19. 192Ir high dose rate (HDR) interstitial brain implant: optimisation

    International Nuclear Information System (INIS)

    Tyagi, Anuj; Singh, Dinesh; Chitra, S.; Gupta, J.P.

    2001-01-01

    The new modality of stepping source dosimetry system (SSDs) illustrates a remarkable improvement in attaining the uniform and homogeneous dose distribution within the target volume. The technique enables the physicist to correct for a certain amount of misplacement or curvature of implant geometry. The short course of brachytherapy provides good palliation in terms of functional improvements with low and acceptable toxicity in high-grade glioma. With continual refinements of the technique, brachytherapy performed by a skilled brachytherapy team offers an opportunity to improve patient survival and quality of life. Since 1997, micro selectron HDR 192 Ir treatments are done including gynecological, oesophageal, breast, surface mould, soft tissue sarcoma (STS) and brain in our hospital. In this paper, procedure of interstitial brain implant in glioma as implant technique, simulation and treatment planning will be discussed

  20. Implementation of microsource high dose rate (mHDR) brachytherapy in developing countries

    International Nuclear Information System (INIS)

    2001-11-01

    Brachytherapy using remote afterloading of a single high dose rate 192 Ir microsource was developed in the 1970s. After its introduction to clinics, this system has spread rapidly among developed Member States and has become a highly desirable modality in cancer treatment. This technique is now gradually being introduced to the developing Member States. The 192 Ir sources are produced with a high specific activity. This results in a high dose rate (HDR) to the tumour and shorter treatment times. The high specific activity simultaneously results in a much smaller source (so-called micro source, around I mm in diameter) which may be easily inserted into tissue through a thin delivery tube, the so-called interstitial treatment, as well as easily inserted into body cavities, the so-called intracavitary or endoluminal treatment. Another advantage is the ability to change dwell time (the time a source remains in one position) of the stepping source which allows dose distribution to match the target volume more closely. The purpose of this TECDOC is to advise radiation oncologists, medical physicists and hospital administrators in hospitals which are planning to introduce 192 Ir microsource HDR (mHDR) remote afterloading systems. The document supplements IAEA-TECDOC-1040, Design and Implementation of a Radiotherapy Programme: Clinical, Medical Physics, Radiation Protection and Safety Aspects, and will facilitate implementation of this new brachytherapy technology, especially in developing countries. The operation of the system, 'how to use the system', is not within the scope of this document. This TECDOC is based on the recommendations of an Advisory Group meeting held in Vienna in April 1999

  1. Who Should Bear the Cost of Convenience? A Cost-effectiveness Analysis Comparing External Beam and Brachytherapy Radiotherapy Techniques for Early Stage Breast Cancer.

    Science.gov (United States)

    McGuffin, M; Merino, T; Keller, B; Pignol, J-P

    2017-03-01

    Standard treatment for early breast cancer includes whole breast irradiation (WBI) after breast-conserving surgery. Recently, accelerated partial breast irradiation (APBI) has been proposed for well-selected patients. A cost and cost-effectiveness analysis was carried out comparing WBI with two APBI techniques. An activity-based costing method was used to determine the treatment cost from a societal perspective of WBI, high dose rate brachytherapy (HDR) and permanent breast seed implants (PBSI). A Markov model comparing the three techniques was developed with downstream costs, utilities and probabilities adapted from the literature. Sensitivity analyses were carried out for a wide range of variables, including treatment costs, patient costs, utilities and probability of developing recurrences. Overall, HDR was the most expensive ($14 400), followed by PBSI ($8700), with WBI proving the least expensive ($6200). The least costly method to the health care system was WBI, whereas PBSI and HDR were less costly for the patient. Under cost-effectiveness analyses, downstream costs added about $10 000 to the total societal cost of the treatment. As the outcomes are very similar between techniques, WBI dominated under cost-effectiveness analyses. WBI was found to be the most cost-effective radiotherapy technique for early breast cancer. However, both APBI techniques were less costly to the patient. Although innovation may increase costs for the health care system it can provide cost savings for the patient in addition to convenience. Copyright © 2016 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  2. Braquiterapia endoluminal HDR no tratamento de tumores primários ou recidivas na árvore traqueobrônquica

    Directory of Open Access Journals (Sweden)

    Maria Fortunato

    2009-03-01

    maciça e três por progressão da doença.Discussão e conclusões Os dts submetidos a BT após recidiva tumoral endobrônquica ou com tumores primários sintomáticos apresentam uma boa tolerância e um alívio sintomático associado a uma boa qualidade de vida. Apesar da reduzida amostra, os resultados demonstram as eventuais vantagens da BTE de HDR no tratamento paliativo/ curativo destes doentes.Rev Port Pneumol 2009; XV (2: 151-164 Abstract: Introduction: Locally advanced tumours as the initial form of presentation of tumours in the bronchial tree are not a rare event. Bronchogenic recurrence is frequent in the natural history of some tumours. The choice of therapeutic options from the raft available depends on such variables as initial therapy, place of recurrence, symptoms and patient’s physical status.Aim: To demonstrate the advantages of endoluminal brachytherapy (EBT with high dose rate (HDR in primary and recurrent tumour of the bronchial tree.Material and methods: A retrospective study of seven patients (pts with primary tumours of the colon, trachea and lung. Tracheobronchial recurrence (trachea, two pts, bronchus, five pts occurred between March 2003 and September 2004. Patients under-went EBT with HDR for primary or recurrent therapy in association with external radiotherapy, laser therapy and chemotherapy with palliative or curative intention. EBT with HDR doses of 5 to 7 Gy in 2 to 4 fractions at 1 cm from the source axis were given. Treatment included endoluminal application of Ir192 with a French 6 catheter.Results: There was symptomatic relief related to reduction of tumour in six of the seven patients treated. In one of the six patients studied, there was progression of the local disease between the second and third fractions of the treatment (obstruction of the trachea. In a mean follow up of 17 (2-40 months between EBT and this study, three patients are alive, one has no evidence of disease while two have had

  3. 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)

  4. Color sensitivity of the multi-exposure HDR imaging process

    Science.gov (United States)

    Lenseigne, Boris; Jacobs, Valéry Ann; Withouck, Martijn; Hanselaer, Peter; Jonker, Pieter P.

    2013-04-01

    Multi-exposure high dynamic range(HDR) imaging builds HDR radiance maps by stitching together different views of a same scene with varying exposures. Practically, this process involves converting raw sensor data into low dynamic range (LDR) images, estimate the camera response curves, and use them in order to recover the irradiance for every pixel. During the export, applying white balance settings and image stitching, which both have an influence on the color balance in the final image. In this paper, we use a calibrated quasi-monochromatic light source, an integrating sphere, and a spectrograph in order to evaluate and compare the average spectral response of the image sensor. We finally draw some conclusion about the color consistency of HDR imaging and the additional steps necessary to use multi-exposure HDR imaging as a tool to measure the physical quantities such as radiance and luminance.

  5. Essential results of analyses accompanying the leak rate experiments E22 at HDR

    International Nuclear Information System (INIS)

    Grebner, H.; Hoefler, A.; Hunger, H.

    1994-01-01

    Under the E22 test group of phase III of the HDR safety programme, experiments were performed on the crack opening and leak rate behaviour of pipe components of smaller nominal bores. The experiments were complemented by computations, in particular verifications, to qualify the computation models as one of the main aims of the HDR safety programme. Most of the analyses to determine crack openings were performed by means of the finite-element method, including elastic-plastic materials behaviour and, complementarily, assessing engineering methods. The leak rate was calculated by means of separate 2-phase computation models. Altogether, it may be concluded from the structural and fracture mechanical experiments with pipes, elbows and branch pieces, that crack openings and incipient cracks at loading with internal pressure or bending moment can be described with good accuracy by means of the finite-element programme ADINA and the developed FE-models. (orig.) [de

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

    Directory of Open Access Journals (Sweden)

    Qingjiao Sun

    2016-01-01

    Full Text Available 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.

  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. Comparison of high dose rate (HDR) and low dose rate (LDR) brachytherapy in the treatment of stage IIIB cervix cancer with radiation therapy alone. The preliminary results

    International Nuclear Information System (INIS)

    Trippe, Nivaldo; Novaes, P.E.; Ferrigno, R.; Pellizzon, A.C.; Salvajoli, J.V.; Fogaroli, R.C.; Maia, M.A.C.; Baraldi, H.E.

    1996-01-01

    Purpose/Objective: To compare the results between HDR and LDR brachytherapy in the treatment of stage IIIB cervix cancer with radiation therapy alone through a prospective and randomized trial. Materials and Methods: From September 1992 to December 1993, 65 patients with stage IIIB cervical cancer were randomized to one of the following treatment schedule according to the brachytherapy used to complement the dose of external beam radiotherapy (EBRT): 1 - High dose rate (HDR) - 36 patients - 4 weekly insertions of 6,0 Gy at point A 2 - Low dose rate (LDR) - 29 patients - 2 insertions two weeks apart of 17,5 Gy at point A The External Beam radiotherapy was performed through a Linac 4MV, in box arrangement for whole pelvis and in AP-PA fields for parametrial complementation of dose. The dose at the whole pelvis was 45 Gy in 25 fractions of 1,8 Gy and the parametrial dose was 16 Gy. The brachytherapy was realized with Fletcher colpostats and intrauterine tandem, in both arms. The HDR brachytherapy was realized through a Micro-Selectron device, working with Iridium-192 with initial activity of 10 Ci and started ten days after the beginning of EBRT. The total treatment time was shortened in two weeks for this group. The LDR brachytherapy started only after the end of EBRT. Results: With the minimum follow up of 24 months and medium of 31 months, the disease free survival was 50% among the 36 patients in HDR group and 47,8% among the 29 patients in LDR group. Local failures occurred in 50% and 52,8% respectively. Grade I and II complications were restricted to rectites and cistites and the incidence of them was 8,3% for HDR group and 13% for LDR group. Until the time of evaluation there were no grade III complications in any group. Conclusions: Although the number of patients is small and the time of follow up still short, these preliminary results suggest that the HDR brachytherapy has an equivalent efficiency in local control as the LDR in the treatment of stage IIIB

  9. Performance evaluation of objective quality metrics for HDR image compression

    Science.gov (United States)

    Valenzise, Giuseppe; De Simone, Francesca; Lauga, Paul; Dufaux, Frederic

    2014-09-01

    Due to the much larger luminance and contrast characteristics of high dynamic range (HDR) images, well-known objective quality metrics, widely used for the assessment of low dynamic range (LDR) content, cannot be directly applied to HDR images in order to predict their perceptual fidelity. To overcome this limitation, advanced fidelity metrics, such as the HDR-VDP, have been proposed to accurately predict visually significant differences. However, their complex calibration may make them difficult to use in practice. A simpler approach consists in computing arithmetic or structural fidelity metrics, such as PSNR and SSIM, on perceptually encoded luminance values but the performance of quality prediction in this case has not been clearly studied. In this paper, we aim at providing a better comprehension of the limits and the potentialities of this approach, by means of a subjective study. We compare the performance of HDR-VDP to that of PSNR and SSIM computed on perceptually encoded luminance values, when considering compressed HDR images. Our results show that these simpler metrics can be effectively employed to assess image fidelity for applications such as HDR image compression.

  10. HDR and LDR Brachytherapy in the Treatment of Lip Cancer: the Experience of the Catalan Institute of Oncology.

    Science.gov (United States)

    Ayerra, Arrate Querejeta; Mena, Estefanía Palacios; Fabregas, Joan Pera; Miguelez, Cristina Gutiérrez; Guedea, Ferran

    2010-03-01

    Lip cancer can be treated by surgery, external radiotherapy, and/or brachytherapy (BT). In recent years, BT has become increasingly favored for this type of cancer. The aim of the present study was to analyze local control and survival of patients treated at our institution between July 1989 and June 2008. We performed a retrospective study of 121 patients (109 males and 12 females) who underwent lip cancer brachytherapy from July 1989 to June 2008. Median age was 67 years and median follow-up was 31.8 months (range 20-188 months). Out of 121 patients, 100 (82.6%) were treated with low dose rate (LDR) BT while the remaining 21 patients (17.4%) received high dose rate (HDR) BT. The most common cell type was squamous cell carcinoma (115 cases; 95%) and most tumors were located on the lower lip (107 patients; 88.4%). Most cases were either stage T1 (62 patients; 51.2%), or T2 (44 cases; 36.4%). After 15 years of follow-up, overall survival was 89.5%, cause-specific survival 97.8%, and disease-free survival 86.6%. Local, regional, and distant control at 15 years were 90%, 92%, and 98.8%, respectively. Grade 3 mucosal toxicity was observed in 23% of patients treated with LDR compared to 33% of HDR patients, and grade 4 mucosal toxicity in 9% versus 0% in the HDR group. Our findings confirm that brachytherapy is an effective treatment for lip cancer. The results from our series are in line with those published elsewhere. Based on our limited data, HDR appears to be equally as good as LDR, although this needs to be confirmed by further studies.

  11. Clinical implementation of a new HDR brachytherapy device for partial breast irradiation

    International Nuclear Information System (INIS)

    Scanderbeg, Daniel J.; Yashar, Catheryn; Rice, Roger; Pawlicki, Todd

    2009-01-01

    Purpose: To present the clinical implementation of a new HDR device for partial breast irradiation, the Strut-Adjusted Volume Implant (SAVI), at the University of California, San Diego. Methods and materials: The SAVI device has multiple peripheral struts that can be differentially loaded with the HDR source. Planning criteria used for evaluation of the treatment plans included the following dose volume histogram (DVH) criteria: V90 >90%, V150 <50 cc and V200 <20 cc. Results: SAVI has been used on 20 patients to date at UC San Diego. In each case, the dose was modulated according to patient-specific anatomy to cover the tumor bed, while sparing normal tissues. The dosimetric data show that we can achieve greater than 90% coverage with respect to V90 (median of 95.3%) and also keep a low V150 and V200 dose at 24.5 and 11.2 cc, respectively. Complete treatment can be done within a 30-min time slot, which includes implant verification, setup, and irradiation time as well as wound dressing. Conclusion: SAVI has been implemented at UC San Diego for accelerated partial breast irradiation with excellent tumor bed conformance and minimal normal tissue exposure. Patient positioning is the key to identifying any inter-fraction device motion. Device asymmetry or tissue conformance has been shown to resolve itself 24 h after the device implantation. The device can be implemented into an existing HDR program with minimal effort

  12. Exclusive radiation therapy of endometrial carcinoma using HDR Co-60 and Cf-252 sources

    International Nuclear Information System (INIS)

    Inciura, A.; Janulionis, E.; Atkocius, V.

    2000-01-01

    Although the main treatment of endometrial cancer is surgery, the gross spread of carcinoma in pelvis, elderly age of the patients and serious therapeutical diseases do not allow to operate 20% of the patients. For these patients only radical treatment decision is the combined radiation therapy. However, using various modalities of combined radiotherapy, the treatment results are not satisfying: only 52% of patients survive 5 years. There was implemented a new method of combined radiotherapy, using a three-channel applicator with two-positional locating of HDR Co-60 radioactive sources (group I). A new method of brachytherapy for endometrial carcinoma using a HDR Cf 252 sources (group II) was implemented too. For group I the medium total dose of the point A was 77.6 Gy, point I - 69.6 Gy. point 2 - 84.2 Gy, point B - 52.6 Gy, For group II the medium total dose the points A, 3 and 4 was 50 iGy. For group I 1 year overaII survival rate was 85%, 3 year - 73%. The 3 year survival rate for stage I was 79%, for stage II - 89%, for stage III - 33%. 3 year survival for highly virulent tumours - 56% and for low virulent (adenocarcinoma) - 82% was statistically different. The loss of tumour differentiation correlated with the worse prognosis: 3 year survival for G1 and G2 tumours was 92%, for G3 - 45%. Low hemoglobin level was also associated with low survival rate: 2 year survival for Hb≥120g/l was 85% and Hb<120g/l - 23%. 1 year survival rate was 87%, 3 year - 66%, 5 year - 58% for group II, treated with Cf-252. Radiation complications occurred for 13.8% of the patients for group I and 6.2% for group II. Good survival rates and a small number of complications sufficiently proofed treatment method. (author)

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

    International Nuclear Information System (INIS)

    Siauw, Timmy; Cunha, Adam; Atamtuerk, Alper; Hsu, I-Chow; Pouliot, Jean; Goldberg, Ken

    2011-01-01

    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 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.

  14. Phase III trial of high and low dose rate interstitial radiotherapy for early oral tongue cancer

    International Nuclear Information System (INIS)

    Inoue, Takehiro; Inoue, Toshihiko; Teshima, Teruki; Murayama, Shigeyuki; Shimizutani, Kimishige; Fuchihata, Hajime; Furukawa, Souhei

    1996-01-01

    Purpose: Oral tongue carcinomas are highly curable with radiotherapy. In the past, patients with tongue carcinoma have usually been treated with low dose rate (LDR) interstitial radiation. This Phase III study was designed to compare the treatment results obtained with LDR with those obtained with high dose rate (HDR) interstitial radiotherapy for tongue carcinoma. Methods and Materials: The criteria for patient selection for the Phase III study were: (a) presence of a T1T2N0 tumor that could be treated with single-plane implantation, (b) localization of tumor at the lateral tongue border, (c) tumor thickness of 10 mm or less, (d) performance status between O and 3, and (e) absence of any severe concurrent disease. From April 1992 through December 1993, 15 patients in the LDR group (70 Gy/4 to 9 days) and 14 patients in the HDR group (60 Gy/10 fractions/6 days) were accrued. The time interval between two fractions of the HDR brachytherapy was more than 6 h. Results: Local recurrence occurred in two patients treated with LDR brachytherapy but in none of the patients treated with HDR. One- and 2-year local control rates for patients in the LDR group were both 86%, compared with 100% in the HDR group (p = 0.157). There were four patients with nodal metastasis in the LDR group and three in the HDR group. Local recurrence occurred in two of the four patients with nodal metastases in the LDR group. One- and 2-year nodal control rates for patients in the LDR group are were 85%, compared with 79% in the HDR group. Conclusion: HDR fractionated interstitial brachytherapy can be an alternative to traditional LDR brachytherapy for early tongue cancer and eliminate the radiation exposure for medical staffs

  15. 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.

  16. Hyperfractionated radiotherapy and simultaneous cisplatin for stage-III and -IV carcinomas of the head and neck. Long-term results including functional outcome

    International Nuclear Information System (INIS)

    Huguenin, P.; Glanzmann, C.; Taussky, D.; Luetolf, U.M.; Schmid, S.; Moe, K.

    1998-01-01

    Purpose: To assess the survival rate, the probability of local control, the patterns of relapse and late sequelae including self-reported quality of life in patients treated with hyperfractionated radiotherapy (RT) and simultaneous CDDP chemotherapy for stage-III to stage-IV carcinomas of the head and neck. Methods: From 1988 to 1994, 64 patients (median age 55.5 years) with carcinomas of different subsites, excluding the nasopharynx, were treated in a pilot study with 1.2 Gy bid (6 h interval; total dose 74.4 Gy) and simultaneous CDDP (20 mg/m 2 daily, 5 days in week 1 and 5) and followed at regular intervals. Overall survival and local control, as well as the rates of late toxicity, were estimated using the actuarial method. Median follow-up was 3.3 years for all and 5.2 years for surviving patients. To assess the quality of life, the EORTC QLQ-C 30 questionnaire and the H and N35 module questionnaire were sent to the patients surviving with no evidence of disease or second primary tumors; they were answered by 15/23 (67%). Results: Overall survival was 37% at 5 years, whereas disease-specific survival was 59%. Twenty-three patients died from uncontrolled head and neck cancer. Second primary tumors were observed in 13 patients, most frequently in the lung. Local control without salvage surgery was 74% at 5 years for all subsites and stages, and loco-regional disease-free survival was 72%. Eleven patients developed distant metastases, which was the only site of failure in 6 cases. Salvage surgery was successful in 2 cases. The actuarial estimates of ≥grade-3 late toxicity was 4% for the mandibular bone and 23% for dysphagia, and 50% of the patients experienced a permanent xerostomy. Self-reported global quality of life in surviving patients was good (mean 68 points on a scale 0 to 100); consequences of impaired salivary function had most impact on nutritional and social aspects. Conclusions: Hyperfractionated RT with concomitant CDDP is well tolerated and highly

  17. 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.

  18. TU-C-201-02: Clinical Implementation of HDR: Afterloader and Applicator Selection

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-06-15

    Recent use of HDR has increased while planning has become more complex often necessitating 3D image-based planning. While many guidelines for the use of HDR exist, they have not kept pace with the increased complexity of 3D image-based planning. Furthermore, no comprehensive document exists to describe the wide variety of current HDR clinical indications. This educational session aims to summarize existing national and international guidelines for the safe implementation of an HDR program. A summary of HDR afterloaders available on the market and their existing applicators will be provided, with guidance on how to select the best fit for each institution’s needs. Finally, the use of checklists will be discussed as a means to implement a safe and efficient HDR program and as a method by which to verify the quality of an existing HDR program. This session will provide the perspective of expert HDR physicists as well as the perspective of a new HDR user. Learning Objectives: Summarize national and international safety and staffing guidelines for HDR implementation Discuss the process of afterloader and applicator selection for gynecologic, prostate, breast, interstitial, surface treatments Learn about the use of an audit checklist tool to measure of quality control of a new or existing HDR program Describe the evolving use of checklists within an HDR program.

  19. TU-C-201-00: Clinical Implementation of HDR Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2015-06-15

    Recent use of HDR has increased while planning has become more complex often necessitating 3D image-based planning. While many guidelines for the use of HDR exist, they have not kept pace with the increased complexity of 3D image-based planning. Furthermore, no comprehensive document exists to describe the wide variety of current HDR clinical indications. This educational session aims to summarize existing national and international guidelines for the safe implementation of an HDR program. A summary of HDR afterloaders available on the market and their existing applicators will be provided, with guidance on how to select the best fit for each institution’s needs. Finally, the use of checklists will be discussed as a means to implement a safe and efficient HDR program and as a method by which to verify the quality of an existing HDR program. This session will provide the perspective of expert HDR physicists as well as the perspective of a new HDR user. Learning Objectives: Summarize national and international safety and staffing guidelines for HDR implementation Discuss the process of afterloader and applicator selection for gynecologic, prostate, breast, interstitial, surface treatments Learn about the use of an audit checklist tool to measure of quality control of a new or existing HDR program Describe the evolving use of checklists within an HDR program.

  20. Traceable calibration of hospital 192Ir HDR sources

    International Nuclear Information System (INIS)

    Govinda Rajan, K.N.; Sharma, S.D.; Palaniselvam, T.; Vandana, S.; Bhatt, B.C.; Vinatha, S.; Patki, V.S.; Pendse, A.M.; Kannan, V.

    2004-01-01

    A HDR 1000 PLUS well type ionization chamber, procured from Standard Imaging, USA, and maintained by medical Physics and Safety Section (MPSS), Bhabha Atomic Research Centre (BARC), India, as a reference well chamber 1 (RWCH1), was traceably calibrated against the primary standard established by Radiological Standards Laboratory (RSL), BARC for 192 Ir HDR source, in terms of air kerma strength (AKS). An indigenously developed well-type ionization chamber, reference well chamber 2 (RWCH2) and electrometer system, fabricated by CD High Tech (CDHT) Instruments Private Ltd., Bangalore, India, was in turn calibrated against RWCH1. The CDHT system (i.e. RWCH2 and CDHT electrometer system) was taken to several hospitals, in different regions of the country, to check the calibration status of 192 Ir HDR sources. The result of this calibration audit work is reported here. (author)

  1. Experience of the first application of HDR brachytherapy in nasopharynx

    International Nuclear Information System (INIS)

    Vega Hernandez, Manuel I.; Alfonso Laguardia, Rodolfo; Silvestre Patallo, Ileana; Roca Muchuli, Carlos; Garcia Heredia, Gilda

    2006-01-01

    A research was made by applying boost on the area of the nasopharynx relapse with high dose rate (HDR) in a diagnosis of nasopharynx carcinoma previously treated with telecobalt therapy, at a dose of 70 Gy. There was persistence of the injury. Three sessions were planned, with consecutive fractions of 6.5 Gy in 15 days, with optimization, using a personal mould of autopolymerizable acrylic. The successful possibility to apply the high rate modern brachytherapy was reaffirmed, as a treatment complementary to teletherapy in case of persistence or relapse. A Micro Selectron HDR equipment was used

  2. Hyperfractionated radiotherapy and simultaneous cisplatin for stage-III and -IV carcinomas of the head and neck. Long-term results including functional outcome

    Energy Technology Data Exchange (ETDEWEB)

    Huguenin, P.; Glanzmann, C.; Taussky, D.; Luetolf, U.M. [Univ. Hospital Zurich (Switzerland). Radiation Oncology Dept.; Schmid, S.; Moe, K. [Univ. Hospital Zurich (Switzerland). Dept. of Head and Neck Surgery

    1998-08-01

    Purpose: To assess the survival rate, the probability of local control, the patterns of relapse and late sequelae including self-reported quality of life in patients treated with hyperfractionated radiotherapy (RT) and simultaneous CDDP chemotherapy for stage-III to stage-IV carcinomas of the head and neck. Methods: From 1988 to 1994, 64 patients (median age 55.5 years) with carcinomas of different subsites, excluding the nasopharynx, were treated in a pilot study with 1.2 Gy bid (6 h interval; total dose 74.4 Gy) and simultaneous CDDP (20 mg/m{sup 2} daily, 5 days in week 1 and 5) and followed at regular intervals. Overall survival and local control, as well as the rates of late toxicity, were estimated using the actuarial method. Median follow-up was 3.3 years for all and 5.2 years for surviving patients. To assess the quality of life, the EORTC QLQ-C 30 questionnaire and the H and N35 module questionnaire were sent to the patients surviving with no evidence of disease or second primary tumors; they were answered by 15/23 (67%). Results: Overall survival was 37% at 5 years, whereas disease-specific survival was 59%. Twenty-three patients died from uncontrolled head and neck cancer. Second primary tumors were observed in 13 patients, most frequently in the lung. Local control without salvage surgery was 74% at 5 years for all subsites and stages, and loco-regional disease-free survival was 72%. Eleven patients developed distant metastases, which was the only site of failure in 6 cases. Salvage surgery was successful in 2 cases. The actuarial estimates of {>=}grade-3 late toxicity was 4% for the mandibular bone and 23% for dysphagia, and 50% of the patients experienced a permanent xerostomy. Self-reported global quality of life in surviving patients was good (mean 68 points on a scale 0 to 100); consequences of impaired salivary function had most impact on nutritional and social aspects. Conclusions: Hyperfractionated RT with concomitant CDDP is well tolerated and

  3. Phase III trial of high- vs. low-dose-rate interstitial radiotherapy for early mobile tongue cancer

    International Nuclear Information System (INIS)

    Inoue, Takehiro; Inoue, Toshihiko; Yoshida, Ken; Yoshioka, Yasuo; Shimamoto, Shigetoshi; Tanaka, Eiichi; Yamazaki, Hideya; Shimizutani, Kimishige; Teshima, Teruki; Furukawa, Souhei

    2001-01-01

    Purpose: Early mobile tongue cancer can be controlled with interstitial radiotherapy (ISRT). We carried out a Phase III trial to compare the treatment results of low-dose-rate (Ld) ISRT and high-dose-rate (HDR) ISRT for early mobile tongue cancer. Methods and Materials: From April 1992 through October 1996, 59 patients with cancer of the early mobile tongue were registered in this Phase III study. Eight patients were excluded from the evaluation because of violations of the requirements for this study. Of 51 eligible patients, 26 patients were treated with LDR-ISRT (70 Gy/4-9 days) and 25 patients with HDR-ISRT (60 Gy/10 fractions/1 week). For the hyperfractionated HDR-ISRT, the time interval between 2 fractions was more than 6 h. Results: Five-year local control rates of the LDR and HDR groups were 84% and 87% respectively. Nodal metastasis occurred in 6 patients in each group. Five-year nodal control rates of the LDR and HDR groups were 77% and 76%, respectively. Conclusion: Hyperfractionated HDR-ISRT for early mobile tongue cancer has the same local control compared with continuous LDR-ISRT. Hyperfractionated HDR-ISRT is an alternative treatment for continuous LDR-ISRT

  4. High-dose-rate brachytherapy as salvage modality for locally recurrent prostate cancer after definitive radiotherapy. A systematic review

    Energy Technology Data Exchange (ETDEWEB)

    Chatzikonstantinou, Georgios; Zamboglou, Nikolaos; Roedel, Claus; Tselis, Nikolaos [J.W. Goethe University of Frankfurt, Department of Radiotherapy and Oncology, Frankfurt am Main (Germany); Zoga, Eleni [Sana Klinikum Offenbach, Department of Radiotherapy and Oncology, Offenbach am Main (Germany); Strouthos, Iosif [Medical Center - University of Freiburg, Department of Radiotherapy and Oncology, University of Freiburg, Freiburg (Germany); Butt, Saeed Ahmed [Sana Klinikum Offenbach, Department of Medical Physics and Engineering, Offenbach am Main (Germany)

    2017-09-15

    To review the current status of interstitial high-dose-rate brachytherapy as a salvage modality (sHDR BRT) for locally recurrent prostate cancer after definitive radiotherapy (RT). A literature search was performed in PubMed using ''high-dose-rate, brachytherapy, prostate cancer, salvage'' as search terms. In all, 51 search results published between 2000 and 2016 were identified. Data tables were generated and summary descriptions created. The main outcome parameters used were biochemical control (BC) and toxicity scores. Eleven publications reported clinical outcome and toxicity with follow-up ranging from 4-191 months. A variety of dose and fractionation schedules were described, including 19.0 Gy in 2 fractions up to 42.0 Gy in 6 fractions. The 5-year BC ranged from 18-77%. Late grade 3 genitourinary and gastrointestinal toxicity was 0-32% and 0-5.1%, respectively. sHDR BRT appears as safe and effective salvage modality for the reirradiation of locally recurrent prostate cancer after definitive RT. (orig.) [German] Zusammenfassende Darstellung relevanter Literatur zur interstitiellen High-Dose-Rate-Brachytherapie als Salvage-Modalitaet (sHDR-BRT) bei der Behandlung des lokal rezidivierten Prostatakarzinoms nach vorausgegangener definitiver Radiotherapie (RT). In der PubMed-Datenbank wurde eine Literaturrecherche mit den Suchbegriffen ''high-dose-rate, brachytherapy, prostate cancer, salvage'' durchgefuehrt. Zwischen den Jahren 2000 und 2016 wurden 51 Publikationen identifiziert. Die biochemische Kontrolle (BC) sowie das assoziierte Toxizitaetsprofil waren onkologische Hauptpunkte in der Analyse der beruecksichtigten Literatur. Von onkologischen Ergebnissen und Toxizitaeten berichteten 11 Publikationen bei einer medianen Nachbeobachtungszeit von 4-191 Monaten. Eine Variabilitaet von Dosis- und Fraktionierungsregimen wurde beschrieben mit totalen physikalischen Dosen von 19,0 Gy in 2 Fraktionen bis zu 42,0 Gy in 6 Fraktionen

  5. Dosimetric analysis at ICRU reference points in HDR-brachytherapy of cervical carcinoma.

    Science.gov (United States)

    Eich, H T; Haverkamp, U; Micke, O; Prott, F J; Müller, R P

    2000-01-01

    In vivo dosimetry in bladder and rectum as well as determining doses on suggested reference points following the ICRU report 38 contribute to quality assurance in HDR-brachytherapy of cervical carcinoma, especially to minimize side effects. In order to gain information regarding the radiation exposure at ICRU reference points in rectum, bladder, ureter and regional lymph nodes those were calculated (digitalisation) by means of orthogonal radiographs of 11 applications in patients with cervical carcinoma, who received primary radiotherapy. In addition, the doses at the ICRU rectum reference point was compared to the results of in vivo measurements in the rectum. The in vivo measurements were by factor 1.5 below the doses determined for the ICRU rectum reference point (4.05 +/- 0.68 Gy versus 6.11 +/- 1.63 Gy). Reasons for this were: calibration errors, non-orthogonal radiographs, movement of applicator and probe in the time span between X-ray and application, missing connection of probe and anterior rectal wall. The standard deviation of calculations at ICRU reference points was on average +/- 30%. Possible reasons for the relatively large standard deviation were difficulties in defining the points, identifying them on radiographs and the different locations of the applicators. Although 3 D CT, US or MR based treatment planning using dose volume histogram analysis is more and more established, this simple procedure of marking and digitising the ICRU reference points lengthened treatment planning only by 5 to 10 minutes. The advantages of in vivo dosimetry are easy practicability and the possibility to determine rectum doses during radiation. The advantages of computer-aided planning at ICRU reference points are that calculations are available before radiation and that they can still be taken into account for treatment planning. Both methods should be applied in HDR-brachytherapy of cervical carcinoma.

  6. Development of optimized dosimetric models for HDR brachytherapy

    International Nuclear Information System (INIS)

    Thayalan, K.; Jagadeesan, M.

    2003-01-01

    High dose rate brachytherapy (HDRB) systems are in clinical use for more than four decades particularly in cervical cancer. Optimization is the method to produce dose distribution which assures that doses are not compromised at the treatment sites whilst reducing the risk of overdosing critical organs. Hence HDRB optimization begins with the desired dose distribution and requires the calculations of the relative weighting factors for each dwell position with out changing the source activity. The optimization for Ca. uterine cervix treatment is simply duplication of the dose distribution used for Low dose rate (LDR) applications. In the present work, two optimized dosimetric models were proposed and studied thoroughly, to suit the local clinical conditions. These models are named as HDR-C and HDR-D, where C and D represent configuration and distance respectively. These models duplicate exactly the LDR pear shaped dose distribution, which is a golden standard. The validity of these models is tested in different clinical situations and in actual patients (n=92). These models: HDR-C and HDR-D reduce bladder dose by 11.11% and 10% and rectal dose by 8% and 7% respectively. The treatment time is also reduced by 12-14%. In a busy hospital setup, these models find a place to cater large number of patients, while addressing individual patients geometry. (author)

  7. 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.

  8. Radiobiological considerations in gynaecological HDR and LDR brachytherapy

    International Nuclear Information System (INIS)

    Bauer, M.; Schulz-Wendtland, R.

    1989-01-01

    In brachytherapy the advantages of high dose rate over low dose rate afterloading therapy were obvious. Out-patient treatment becomes possible, the position of the sources is reproducible and can be observed during the treatment and the patients have to be immobilised for only a short time, giving less psychological stress and a decreased risk of thrombosis and embolism. When changing from LDR to HDR afterloading therapy we are not yet able to evaluate its biological impact. Radiobiological considerations and our experimental data, however, give us the following clinical consequences by using HDR brachytherapy: There is a need for about 15 fractions or more and each increase in dose rate requires higher fractioning. Due to the steep dose rate decline and the inhomogeneous dose distribution, multiple equivalence factors are necessary when fractioning is not sufficiently high. Correction factors to reduce the dose close to the source are low, with increasing distance from the source they increase. If HDR radiation therapy is used, the percutaneous dose in the pelvic wall region should be reduced. The reduction of the dose in HDR brachytherapy is a compromise to limit the side effects caused by the radiation. The drawback is a small therapeutic range and reduced therapeutic effectivity at the tumour. (orig.) [de

  9. SU-G-JeP2-14: MRI-Based HDR Prostate Brachytherapy: A Phantom Study for Interstitial Catheter Reconstruction with 0.35T MRI Images

    International Nuclear Information System (INIS)

    Park, S; Kamrava, M; Yang, Y

    2016-01-01

    Purpose: To evaluate the accuracy of interstitial catheter reconstruction with 0.35T MRI images for MRI-based HDR prostate brachytherapy. Methods: Recently, a real-time MRI-guided radiotherapy system combining a 0.35T MRI system and three cobalt 60 heads (MRIdian System, ViewRay, Cleveland, OH, USA) was installed in our department. A TrueFISP sequence for MRI acquisition at lower field on Viewray was chosen due to its fast speed and high signal-to-noise efficiency. Interstitial FlexiGuide needles were implanted into a tissue equivalent ultrasound prostate phantom (CIRS, Norfolk, Virginia, USA). After an initial 15s pilot MRI to confirm the location of the phantom, planning MRI was acquired with a 172s TrueFISP sequence. The pulse sequence parameters included: flip angle = 60 degree, echo time (TE) =1.45 ms, repetition time (TR) = 3.37 ms, slice thickness = 1.5 mm, field of view (FOV) =500 × 450mm. For a reference image, a CT scan was followed. The CT and MR scans were then fused with the MIM Maestro (MIM software Inc., Cleveland, OH, USA) and sent to the Oncentra Brachy planning system (Elekta, Veenendaal, Netherlands). Automatic catheter reconstruction using CT and MR image intensities followed by manual reconstruction was used to digitize catheters. The accuracy of catheter reconstruction was evaluated from the catheter tip location. Results: The average difference between the catheter tip locations reconstructed from the CT and MR in the transverse, anteroposterior, and craniocaudal directions was −0.1 ± 0.1 mm (left), 0.2 ± 0.2 mm (anterior), and −2.3 ± 0.5 mm (cranio). The average distance in 3D was 2.3 mm ± 0.5 mm. Conclusion: This feasibility study proved that interstitial catheters can be reconstructed with 0.35T MRI images. For more accurate catheter reconstruction which can affect final dose distribution, a systematic shift should be applied to the MR based catheter reconstruction in HDR prostate brachytherapy.

  10. Braquiterapia endoluminal HDR no tratamento de tumores primários ou recidivas na árvore traqueobrônquica Endoluminal high dose rate brachytherapy in the treatment of primary and recurrent bronchogenic tree malignancies

    Directory of Open Access Journals (Sweden)

    Maria Fortunato

    2009-03-01

    primários sintomáticos apresentam uma boa tolerância e um alívio sintomático associado a uma boa qualidade de vida. Apesar da reduzida amostra, os resultados demonstram as eventuais vantagens da BTE de HDR no tratamento paliativo/ curativo destes doentesIntroduction: Locally advanced tumours as the initial form of presentation of tumours in the bronchial tree are not a rare event. Bronchogenic recurrence is frequent in the natural history of some tumours. The choice of therapeutic options from the raft available depends on such variables as initial therapy, place of recurrence, symptoms and patient’s physical status. Aim: To demonstrate the advantages of endoluminal brachytherapy (EBT with high dose rate (HDR in primary and recurrent tumour of the bronchial tree. Material and methods: A retrospective study of seven patients (pts with primary tumours of the colon, trachea and lung. Tracheobronchial recurrence (trachea, two pts, bronchus, five pts occurred between March 2003 and September 2004. Patients under-went EBT with HDR for primary or recurrent therapy in association with external radiotherapy, laser therapy and chemotherapy with palliative or curative intention. EBT with HDR doses of 5 to 7 Gy in 2 to 4 fractions at 1 cm from the source axis were given. Treatment included endoluminal application of Ir192 with a French 6 catheter. Results: There was symptomatic relief related to reduction of tumour in six of the seven patients treated. In one of the six patients studied, there was progression of the local disease between the second and third fractions of the treatment (obstruction of the trachea. In a mean follow up of 17 (2-40 months between EBT and this study, three patients are alive, one has no evidence of disease while two have had bronchial recurrence, four patients have died, one after massive haemoptysis and three due to disease progression. Discussion and conclusions: Patients undergoing brachytherapy for symptomatic primary tumours or

  11. Quality assurance in radiotherapy dosimetry in China

    International Nuclear Information System (INIS)

    Li Kaibao; Luo Suming; Cheng Jinsheng; He Zhijian; An Jinggang; Hu Yimin; Feng Ningyuan

    2002-01-01

    In 1995, the SSDL in the Laboratory of Industrial Hygiene cooperated with Beijing Cancer Hospital, Chinese Academy of Medical science joined the IAEA Co-ordinated Research Programme (NO.8769/RO). According to the requirements of the project, an External Audit Group (EAG) in China was established in 1996 with the responsibilities of operating TLD-based quality audit for radiotherapy dosimetry. Since then. The national TLD dose quality audit services have been carried out in 7 provinces in China. Besides this, the national programmes for brachytherapy and stereostatic radiosurgery (SRS) treatment dosimetry were initiated in 2001. The activity measurement intercomparison between the SSDL and some hospitals for Ir-192 HDR brachytherapy sources has been performed using a HDR well-type ionization chamber (Model HDR 1000 plus) and CDX-2000A Charge Digitizer, which were calibrated in Accredited Dosimetry Calibration Laboratory, University of Wisconsin, USA. The preliminary results indicated that the agreement between SSDL measured activity and hospital stated activity was within ±5% for more than 80% of total participants

  12. On-line conformal HDR dose escalation trial in prostate cancer

    International Nuclear Information System (INIS)

    Martinez, Alvaro; Stromberg, Jannifer; Edmundson, Gregory; Gustafson, Gary; Vicini, Frank; Brabbins, Donald

    1996-01-01

    Purpose: To improve treatment results on prostatic adenocarcinoma, we began the first prospective Phase I/II dose-escalating clinical trial of conformal brachytherapy (CB) and concurrent external beam irradiation. Methods and Materials: Fifty-four patients with T2b-T3c prostatic adenocarcinoma received 172 transperineal conformal high-dose rate (HDR) boost implants. All patients received concomitant external beam pelvic irradiation. Dose escalation of the three HDR fractions were: 5.5 Gy (18 patients), 6 Gy (15 patients), and 6.5 Gy (21 patients). The urethra, anterior rectal wall, and prostate boundaries were identified individually and outlined at 5 mm intervals from the base to the apex of the gland. The CB using real-time ultrasound guidance with interactive online isodose distributions was performed on an outpatient basis. As needles were placed into the prostate, corrections for prostate displacement were recorded and the isodose distributions were recalculated to represent the new relationship between the needles, prostate, and normal structures. Results: Craniocaudal motion of the gland ranged from 0.5-2.0 cm (mean=1.0 cm), whereas lateral displacement was 0.1-0.4 cm. With the interactive online planning system, organ motion was immediately detected, accounted for, and corrected prior to each HDR treatment. The rectal dose has ranged from 45 to 87%, and the urethral dose from 97 to 112% of the prostate dose. Negative prostatic biopsies at 18 months were seen in (30(32)) patients. Biochemical (PSA <1.5 ng/ml) control at 36 months is is 89%. It is significant that operator dependence has been completely removed because the interactive online planning system uniformly guides the physicians. Conclusions: With ultrasound guidance and the interactive online dosimetry system, organ motion is insignificant because it can be corrected during the procedure. Common pitfalls of brachytherapy, including operator dependence and difficulty with reproducibility, have been

  13. Salvage high-dose-rate brachytherapy for local prostate cancer recurrence after radical radiotherapy

    Directory of Open Access Journals (Sweden)

    V. A. Solodkiy

    2016-01-01

    Full Text Available Studies salvage interstitial radiation therapy for recurrent prostate cancer, launched at the end of the XX century. In recent years, more and more attention is paid to high-dose-rate brachytherapy (HDR-BT as a method of treating local recurrence.The purpose of research – preliminary clinical results of salvage high-dose-rate brachytherapy applied in cases of suspected local recurrence or of residual tumour after radiotherapy.Preliminary findings indicate the possibility of using HDR-BT, achieving local tumor control with low genitourinary toxicity.

  14. Results of combined photodynamic therapy (PDT) and high dose rate brachytherapy (HDR) in treatment of obstructive endobronchial non-small cell lung cancer

    Science.gov (United States)

    Weinberg, Benjamin D.; Allison, Ron R.; Sibata, Claudio; Parent, Teresa; Downie, Gordon

    2009-06-01

    We reviewed the outcome of combined photodynamic therapy (PDT) and high dose rate brachytherapy (HDR) for patients with symptomatic obstruction from endobronchial non-small cell lung cancer. Methods: Nine patients who received combined PDT and HDR for endobronchial cancers were identified and their charts reviewed. The patients were eight males and one female aged 52-73 at diagnosis, initially presenting with various stages of disease: stage IA (N=1), stage IIA (N=1), stage III (N=6), and stage IV (N=1). Intervention was with HDR (500 cGy to 5 mm once weekly for 3 weeks) and PDT (2 mg/kg Photofrin, followed by 200 J/cm2 illumination 48 hours post infusion). Treatment group 1 (TG-1, N=7) received HDR first; Treatment group 2 (TG-2, N=2) received PDT first. Patients were followed by regular bronchoscopies. Results: Treatments were well tolerated, all patients completed therapy, and none were lost to follow-up. In TG-1, local tumor control was achieved in six of seven patients for: 3 months (until death), 15 months, 2+ years (until death), 2+ years (ongoing), and 5+ years (ongoing, N=2). In TG-2, local control was achieved in only one patient, for 84 days. Morbidities included: stenosis and/or other reversible benign local tissue reactions (N=8); photosensitivity reaction (N=2), and self-limited pleural effusion (N=2). Conclusions: Combined HDR/PDT treatment for endobronchial tumors is well tolerated and can achieve prolonged local control with acceptable morbidity when PDT follows HDR and when the spacing between treatments is one month or less. This treatment regimen should be studied in a larger patient population.

  15. High-dose-rate brachytherapy as salvage modality for locally recurrent prostate cancer after definitive radiotherapy. A systematic review

    International Nuclear Information System (INIS)

    Chatzikonstantinou, Georgios; Zamboglou, Nikolaos; Roedel, Claus; Tselis, Nikolaos; Zoga, Eleni; Strouthos, Iosif; Butt, Saeed Ahmed

    2017-01-01

    To review the current status of interstitial high-dose-rate brachytherapy as a salvage modality (sHDR BRT) for locally recurrent prostate cancer after definitive radiotherapy (RT). A literature search was performed in PubMed using ''high-dose-rate, brachytherapy, prostate cancer, salvage'' as search terms. In all, 51 search results published between 2000 and 2016 were identified. Data tables were generated and summary descriptions created. The main outcome parameters used were biochemical control (BC) and toxicity scores. Eleven publications reported clinical outcome and toxicity with follow-up ranging from 4-191 months. A variety of dose and fractionation schedules were described, including 19.0 Gy in 2 fractions up to 42.0 Gy in 6 fractions. The 5-year BC ranged from 18-77%. Late grade 3 genitourinary and gastrointestinal toxicity was 0-32% and 0-5.1%, respectively. sHDR BRT appears as safe and effective salvage modality for the reirradiation of locally recurrent prostate cancer after definitive RT. (orig.) [de

  16. An easy irradiation technique (partial half-beam) to reduce renal dose in radiotherapy of cervical cancer including paraaortic lymph nodes

    International Nuclear Information System (INIS)

    Vorwerk, H.; Wagner, D.; Christiansen, H.; Hess, C.F.; Hermann, R.M.

    2008-01-01

    Purpose: for radiation treatment of patients with cervical cancer and a high risk for paraaortic lymph node involvement, an easy three-dimensional (3-D) conformal irradiation technique (partial half-beam [PHB]) for protection of organs at risk, especially of renal tissue, was developed. Patients and methods: in five consecutive female patients a computed tomography scan was performed. Dose-volume histograms of the renal tissue and other organs at risk were analyzed for PHB, three other 3-D conformal techniques, and an intensity-modulated radiotherapy (IMRT) technique. Results: the PHB technique reduced the renal volume and volumes of other organs at risk exposed to radiation doses when comparing all patients to the other 3-D conformal techniques. With use of the IMRT technique more renal tissue volume received very low radiation doses (≤ 6.8 Gy) whereas the D 10 was lower than with the PHB technique. Conclusion: in female patients with cervical cancer and high risk for paraaortic lymph node involvement, the use of the PHB technique is recommended to reduce renal radiation exposure, if no IMRT technique should be applied. The PHB technique is very easily and fast applicable. (orig.)

  17. Occurrence Prospect of HDR and Target Site Selection Study in Southeastern of China

    Science.gov (United States)

    Lin, W.; Gan, H.

    2017-12-01

    Hot dry rock (HDR) geothermal resource is one of the most important clean energy in future. Site selection a HDR resource is a fundamental work to explore the HDR resources. This paper compiled all the HDR development projects domestic and abroad, and summarized the location of HDR geothermal geological index. After comparing the geological background of HDR in the southeast coastal area of China, Yangjiang Xinzhou in Guangdong province, Leizhou Peninsula area, Lingshui in Hainan province and Huangshadong in Guangzhou were selected from some key potential target area along the southeast coast of China. Deep geothermal field model of the study area is established based on the comprehensive analysis of the target area of deep geothermal geological background and deep thermal anomalies. This paper also compared the hot dry rock resources target locations, and proposed suggestions for the priority exploration target area and exploration scheme.

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

    Science.gov (United States)

    Pujades, Ma Carmen; Camacho, Cristina; Perez-Calatayud, Jose; Richart, José; Gimeno, Jose; Lliso, Françoise; Carmona, Vicente; Ballester, Facundo; Crispín, Vicente; Rodríguez, Silvia; Tormo, Alejandro

    2011-09-01

    The common use of nomograms in Low Dose Rate (LDR) permanent prostate brachytherapy (BT) allows to estimate the number of seeds required for an implant. Independent dosimetry verification is recommended for each clinical dosimetry in BT. Also, nomograms can be useful for dose calculation quality assurance and they could be adapted to High Dose Rate (HDR). This work sets nomograms for LDR and HDR prostate-BT implants, which are applied to three different institutions that use different implant techniques. Patients treated throughout 2010 till April 2011 were considered for this study. This example was chosen to be the representative of the latest implant techniques and to ensure consistency in the planning. A sufficient number of cases for both BT modalities, prescription dose and different work methodology (depending on the institution) were taken into account. The specific nomograms were built using the correlation between the prostate volume and some characteristic parameters of each BT modality, such as the source Air Kerma Strength, number of implanted seeds in LDR or total radiation time in HDR. For each institution and BT modality, nomograms normalized to the prescribed dose were obtained and fitted 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 centre should construct its own nomograms. Nomograms for LDR and HDR prostate brachytherapy are simple quality assurance tools, specific for each institution. Nevertheless, their use should be complementary to the necessary independent verification.

  19. 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.

  20. Rendering of HDR content on LDR displays: an objective approach

    Science.gov (United States)

    Krasula, Lukáš; Narwaria, Manish; Fliegel, Karel; Le Callet, Patrick

    2015-09-01

    Dynamic range compression (or tone mapping) of HDR content is an essential step towards rendering it on traditional LDR displays in a meaningful way. This is however non-trivial and one of the reasons is that tone mapping operators (TMOs) usually need content-specific parameters to achieve the said goal. While subjective TMO parameter adjustment is the most accurate, it may not be easily deployable in many practical applications. Its subjective nature can also influence the comparison of different operators. Thus, there is a need for objective TMO parameter selection to automate the rendering process. To that end, we investigate into a new objective method for TMO parameters optimization. Our method is based on quantification of contrast reversal and naturalness. As an important advantage, it does not require any prior knowledge about the input HDR image and works independently on the used TMO. Experimental results using a variety of HDR images and several popular TMOs demonstrate the value of our method in comparison to default TMO parameter settings.

  1. Vibrational experiments at the HDR [Heissdampfreaktor] German/US cooperation

    International Nuclear Information System (INIS)

    Kot, C.A.; Malcher, L.; Costello, J.F.

    1987-04-01

    As part of an overall effort on the validation of seismic calculational methods, the US NRC/RES is collaborating with the Kernforschungszentrum Karlsruhe, FRG, in the vibrational/earthquake experiments conducted at the HDR (Heissdampfreaktor) Test Facility in Kahl/Main, FRG. In the most recent experiments (SHAG), high level excitations were produced in the HDR by means of an eccentric-mass coastdown shaker capable of developing 1000 tons of force. The purpose of the experiments was to investigate full-scale structural response, soil-structure interaction, and piping and equipment response. Data obtained in the tests serve to evaluate analysis methods. In the SHAG experiments, loadings of the HDR soil-structure system approached incipient failure levels as evidenced by high peak accelerations and displacements, local damage, nonlinear behavior, soil subsidence, and wall strains which exceeded estimated limit values. Also, the performance of different pipe hanger configurations for the VKL piping system was compared in these tests under high excitation levels. The support configurations ranged from very rigid systems (strut/snubbers) to very flexible configurations (spring and constant force supports). Pretest and post-test analyses for the building/soil and piping response were performed and are being validated with the test data

  2. 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.

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

    International Nuclear Information System (INIS)

    Craciunescu, O; Todor, D; Leeuw, A de

    2014-01-01

    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

  4. A multicentre ‘end to end’ dosimetry audit for cervix HDR brachytherapy treatment

    International Nuclear Information System (INIS)

    Palmer, Antony L.; Diez, Patricia; Gandon, Laura; Wynn-Jones, Andrea; Bownes, Peter; Lee, Chris; Aird, Edwin; Bidmead, Margaret; Lowe, Gerry; Bradley, David; Nisbet, Andrew

    2015-01-01

    Purpose: To undertake the first multicentre fully ‘end to end’ dosimetry audit for HDR cervix brachytherapy, comparing planned and delivered dose distributions around clinical treatment applicators, with review of local procedures. Materials and methods: A film-dosimetry audit was performed at 46 centres, including imaging, applicator reconstruction, treatment planning and delivery. Film dose maps were calculated using triple-channel dosimetry and compared to RTDose data from treatment planning systems. Deviations between plan and measurement were quantified at prescription Point A and using gamma analysis. Local procedures were also discussed. Results: The mean difference between planned and measured dose at Point A was −0.6% for plastic applicators and −3.0% for metal applicators, at standard uncertainty 3.0% (k = 1). Isodose distributions agreed within 1 mm over a dose range 2–16 Gy. Mean gamma passing rates exceeded 97% for plastic and metal applicators at 3% (local) 2 mm criteria. Two errors were found: one dose normalisation error and one applicator library misaligned with the imaged applicator. Suggestions for quality improvement were also made. Conclusions: The concept of ‘end to end’ dosimetry audit for HDR brachytherapy has been successfully implemented in a multicentre environment, providing evidence that a high level of accuracy in brachytherapy dosimetry can be achieved

  5. Essential results of analyses accompanying the leak rate experiments E22 at HDR

    International Nuclear Information System (INIS)

    Grebner, H.; Hoefler, A.; Hunger, H.

    1997-01-01

    During phase III of the HDR Safety Programme (HDR: decommissioned overheated steam reactor in Karlstein, Germany), experiments were performed in test group E22 on small-bore austenitic straight piping and on pipe elbows and branches containing through-wall cracks. The main aim was the determination of crack opening and leak rate behaviour for the cracked components under almost operational pressure and temperature loading conditions, especially including transient bending moments. In addition to machined slits, naturally grown fatigue cracks were also considered to cover the leakage behaviour. The experiments were accompanied by calculations, mainly performed by GRS. The paper describes the most important aspects and the essential results of the calculations and analysis. The main outcome was that the crack opening and initiation of crack growth can be described with the finite element techniques applied with sufficient accuracy. However, the qualification of the leak rate models could not be completed successfully, and therefore more sophisticated experiments of this kind are needed. (orig.)

  6. Independent technique of verifying high-dose rate (HDR) brachytherapy treatment plans

    International Nuclear Information System (INIS)

    Saw, Cheng B.; Korb, Leroy J.; Darnell, Brenda; Krishna, K. V.; Ulewicz, Dennis

    1998-01-01

    Purpose: An independent technique for verifying high-dose rate (HDR) brachytherapy treatment plans has been formulated and validated clinically. Methods and Materials: In HDR brachytherapy, dwell times at respective dwell positions are computed, using an optimization algorithm in a HDR treatment-planning system to deliver a specified dose to many target points simultaneously. Because of the variability of dwell times, concerns have been expressed regarding the ability of the algorithm to compute the correct dose. To address this concern, a commercially available low-dose rate (LDR) algorithm was used to compute the doses at defined distances, based on the dwell times obtained from the HDR treatment plans. The percent deviation between doses computed using the HDR and LDR algorithms were reviewed for HDR procedures performed over the last year. Results: In this retrospective study, the difference between computed doses using the HDR and LDR algorithms was found to be within 5% for about 80% of the HDR procedures. All of the reviewed procedures have dose differences of less than 10%. Conclusion: An independent technique for verifying HDR brachytherapy treatment plans has been validated based on clinical data. Provided both systems are available, this technique is universal in its applications and not limited to either a particular implant applicator, implant site, or implant type

  7. Air-kerma evaluation at the maze entrance of HDR brachytherapy facilities

    International Nuclear Information System (INIS)

    Pujades, M C; Granero, D; Vijande, J; Ballester, F; Perez-Calatayud, J; Papagiannis, P; Siebert, F A

    2014-01-01

    In the absence of procedures for evaluating the design of brachytherapy (BT) facilities for radiation protection purposes, the methodology used for external beam radiotherapy facilities is often adapted. The purpose of this study is to adapt the NCRP 151 methodology for estimating the air-kerma rate at the door in BT facilities. Such methodology was checked against Monte Carlo (MC) techniques using the code Geant4. Five different facility designs were studied for 192 Ir and 60 Co HDR applications to account for several different bunker layouts. For the estimation of the lead thickness needed at the door, the use of transmission data for the real spectra at the door instead of the ones emitted by 192 Ir and 60 Co will reduce the lead thickness by a factor of five for 192 Ir and ten for 60 Co. This will significantly lighten the door and hence simplify construction and operating requirements for all bunkers. The adaptation proposed in this study to estimate the air-kerma rate at the door depends on the complexity of the maze: it provides good results for bunkers with a maze (i.e. similar to those used for linacs for which the NCRP 151 methodology was developed) but fails for less conventional designs. For those facilities, a specific Monte Carlo study is in order for reasons of safety and cost-effectiveness. (paper)

  8. Air-kerma evaluation at the maze entrance of HDR brachytherapy facilities.

    Science.gov (United States)

    Pujades, M C; Granero, D; Vijande, J; Ballester, F; Perez-Calatayud, J; Papagiannis, P; Siebert, F A

    2014-12-01

    In the absence of procedures for evaluating the design of brachytherapy (BT) facilities for radiation protection purposes, the methodology used for external beam radiotherapy facilities is often adapted. The purpose of this study is to adapt the NCRP 151 methodology for estimating the air-kerma rate at the door in BT facilities. Such methodology was checked against Monte Carlo (MC) techniques using the code Geant4. Five different facility designs were studied for (192)Ir and (60)Co HDR applications to account for several different bunker layouts.For the estimation of the lead thickness needed at the door, the use of transmission data for the real spectra at the door instead of the ones emitted by (192)Ir and (60)Co will reduce the lead thickness by a factor of five for (192)Ir and ten for (60)Co. This will significantly lighten the door and hence simplify construction and operating requirements for all bunkers.The adaptation proposed in this study to estimate the air-kerma rate at the door depends on the complexity of the maze: it provides good results for bunkers with a maze (i.e. similar to those used for linacs for which the NCRP 151 methodology was developed) but fails for less conventional designs. For those facilities, a specific Monte Carlo study is in order for reasons of safety and cost-effectiveness.

  9. Study of the dosimetric response of Gallium Nitride (GaN): modeling, simulation and characterization on radiotherapy

    International Nuclear Information System (INIS)

    Wang, Ruoxi

    2015-01-01

    The work in this thesis has the objective to increase the measurement precision of the dosimetry based on the Gallium Nitride (GaN) transducer and develop its applications on radiotherapy. The study includes the aspects of modeling, simulation and characterization of this response in external radiotherapy and brachytherapy. In modeling, we have proposed two approaches to model the GaN transducer's response in external radiotherapy. For the first approach, a model has been built based on experimental data, while separating the primary and scattering component of the beam. For the second approach, we have adopted a response model initially developed for the silicon diodes for the GaN radioluminescent transducer. We have also proposed an original concept of bi-media dosimetry which evaluates the dose in tissue according to different responses from two media without prior information on the conditions of irradiation. This concept has been shown by Monte Carlo simulation. Moreover, for High Dose Rate brachytherapy, the response of GaN transducer irradiated by iridium 192 and cobalt 60 sources has been evaluated by Monte Carlo simulation and confirmed by the measurements. Studies on the property characterization of GaN radioluminescent transducer has been carried out with these sources as well. An instrumented phantom prototype with GaN probe has been developed for the HDR brachytherapy quality control. It allows a real-time verification of the physics parameters of a treatment (source dwell position, source dwell time, source activity). (author) [fr

  10. Postmastectomy radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Shikama, Naoto; Koguchi, Masahiko; Sasaki, Shigeru; Kaneko, Tomoki; Shinoda, Atsunori; Nishikawa, Atsushi [Shinshu Univ., Matsumoto, Nagano (Japan). School of Medicine

    2000-10-01

    Since there have been few reports on postmastectomy radiotherapy having a high evidence level in Japan, the significance of postoperative radiotherapy and the irradiation techniques were reviewed based on reports from Western countries. Authors focused on the indications for postoperative irradiation, irradiation methods (irradiation sites, irradiation techniques; prosthetics, methods of irradiating the chest wall and lymph nodes, timing of irradiation), and complications, and discuss them. The factors thought to be adaptable to postmastectomy radiotherapy have been listed. Axillary lymph node metastasis and the size of the primary focus are thought to be important factors in locoregional recurrence. The chest wall and the supraclavicular lymph nodes are the usual sites of irradiation after mastectomy. The irradiation method consists of tangential irradiation of the chest wall and single-field irradiation of the supraclavicular lymph nodes, with 46-50 Gy in fractional doses of 1.8-2 Gy x 5/w is administered for 4.5-5.5 weeks. The timing of irradiation in the West is generally after chemotherapy. Adverse radiation effects include ischemic heart disease, pneumonitis, arm edema, rib fractures, and brachial plexus paralysis. The frequency of these complications is increased by the combined use of chemotherapy or surgery. The breast cancer cure rate in Japan is generally better than in the West. It remains to be determined whether the clinical data from Europe and America are applicable to the treatment of breast cancer in Japan. To address this issue, a clinical investigation should be performed in Japan with close cooperation between surgeons, physicians, pathologists, and radiotherapists. (K.H.)

  11. Radiotherapy injuries in children

    International Nuclear Information System (INIS)

    Kalifa, G.; Bennet, J.; Couanet, D.; Masselot, J.

    1985-01-01

    Side effects of radiotherapy in pediatrics are reviewed including bone injuries and radio-induced bone tumors; nervous system injuries with emphasis on hypothalamus, pituitary gland, brain and spinal cord; lung, digestive system and urinary tract injuries [fr

  12. Comparison of the outcome and morbidity for localized or locally advanced prostate cancer treated by high-dose-rate brachytherapy plus external beam radiotherapy (EBRT) versus EBRT alone

    International Nuclear Information System (INIS)

    Fang Fumin; Wang Yuming; Wang Chongjong; Huang Hsuanying; Chiang Pohui

    2008-01-01

    The objective of this study was to compare the survival, gastrointestinal (GI) and genitourinary (GU) toxicity for localized or locally advanced prostate cancer treated by high-dose-rate-brachytherapy (HDR-BT) plus external beam radiotherapy (EBRT) versus EBRT alone at a single institute in Taiwan. Eighty-eight patients with T1c-T3b prostate cancer consecutively treated by EBRT alone (33 patients) or HDR-BT+EBRT (55 patients) were studied. The median dose of EBRT was 70.2 Gy in the EBRT group and 50.4 Gy in the HDR-BT group. HDR-BT was performed 2-3 weeks before EBRT, with 12.6 Gy in three fractions over 24 h. Five patients (15.2%) in the EBRT group and seven (12.7%) in the HDR-BT group developed a biochemical relapse. The 5-year actuarial biochemical relapse-free survival rates were 65.0% in the EBRT group and 66.7% in the HDR-BT group (P=0.76). The 5-year actuarial likelihood of late ≥Grade 2 and ≥Grade 3 GI toxicity in the EBRT versus HDR-BT group was 62.8 versus 7.7% (P<0.001) and 19.6 versus 0% (P=0.001), respectively. In a multivariate analysis, the only predictor for late GI toxicity was the mode of RT. The 5-year actuarial likelihood of late ≥Grade 2 and ≥Grade 3 GU toxicity in the EBRT versus HDR-BT group was 14.8 versus 15.9% (P=0.86) and 3.6 versus 8.5% (P=0.40), respectively. The addition of HDR-BT before EBRT with a reduced dose from the EBRT produces a comparable survival outcome and GU toxicity but a significantly less GI toxicity for prostate cancer patients. (author)

  13. A regional cooperative clinical study of radiotherapy for cervical cancer in east and south-east Asian countries

    International Nuclear Information System (INIS)

    Nakano, Takashi; Kato, Shingo; Cao, Jianping; Zhou Juying; Susworo, Raden; Supriana, Nana; Sato, Shinichiro; Ohno, Tatsuya; Suto, Hisao; Nakamura, Yuzuru; Cho, Chul-Koo; Ismail, Fuad B.; Calaguas, Miriam J.C.; Reyes, Rey H. de los; Chansilpa, Yaowalak; Thephamongkhol, Kullathom; Nguyen Ba Duc; To Anh Dung; Tsujii, Hirohiko

    2007-01-01

    Purpose: Radiotherapy differed widely in east and south-east Asia because of technical, cultural, and socio-economic differences. With the purpose of standardizing radiotherapy for cervical cancer in the region, an international clinical study was conducted. Materials and methods: Eleven institutions in eight Asian countries participated in the study. Between 1996 and 1998, 210 patients with stage IIIB cervical cancer were enrolled. Patients were treated with a combination of external beam radiotherapy (total dose, 50 Gy) and either high-dose-rate (HDR) or low-dose-rate (LDR) intracavitary brachytherapy (ICBT) according to the institutional practice. The planned point A dose was 20-28 Gy/4 fractions for HDR-ICBT and 30-40 Gy/1-2 fractions for LDR-ICBT. Results: Hundred patients were treated with HDR-ICBT and 110 were treated with LDR-ICBT. The ICBT doses actually delivered to point A ranged widely: 12-32 Gy in the HDR group and 26-52.7 Gy in the LDR group. The 5-year follow-up rate among the countries differed greatly, from 29% to 100%. The 5-year major complication rates were 6% in the HDR group and 10% in the LDR group. The 5-year overall survival rates were 51.1% in the HDR group and 57.5% in the LDR group. Conclusions: Although there were several problems with treatment compliance and patients' follow-up, the study suggests that the protocols provided favorable outcomes with acceptable rates of late complications in the treatment of advanced cervical cancer in east and south-east Asia

  14. Practice patterns of radiotherapy in cervical cancer among member groups of the Gynecologic Cancer Intergroup (GCIG).

    Science.gov (United States)

    Gaffney, David K; Du Bois, Andreas; Narayan, Kailash; Reed, Nick; Toita, Takafumi; Pignata, Sandro; Blake, Peter; Portelance, Lorraine; Sadoyze, Azmat; Pötter, Richard; Colombo, Alessandro; Randall, Marcus; Mirza, Mansoor R; Trimble, Edward L

    2007-06-01

    The aim of this study was to describe radiotherapeutic practice of the treatment of cervical cancer in member groups of the Gynecologic Cancer Intergroup (GCIG). A survey was developed and distributed to the members of the GCIG focusing on details of radiotherapy practice. Different scenarios were queried including advanced cervical cancer, postoperative patients, and para-aortic-positive lymph node cases. Items focused on indications for radiation therapy, radiation fields, dose, use of chemotherapy, brachytherapy and others. The cooperative groups from North America were compared with the other groups to evaluate potential differences in radiotherapy doses. A total of 39 surveys were returned from 13 different cooperative groups. For the treatment of advanced cervical cancer, external beam pelvic doses and total doses to point A were 47 + 3.5 Gy (mean + SD) and 79.1 + 7.9 Gy, respectively. Point A doses were not different between the North American cooperative groups compared with the others (p = 0.103). All groups used concomitant chemotherapy, with 30 of 36 respondents using weekly cisplatin. Of 33 respondents, 31 intervened for a low hemoglobin level. For a para-aortic field, the upper border was most commonly (15 of 24) at the T12-L1 interspace. Maintenance chemotherapy (after radiotherapy) was not performed by 68% of respondents. For vaginal brachytherapy after hysterectomy, 23 groups performed HDR brachytherapy and four groups used LDR brachytherapy. In the use of brachytherapy, there was no uniformity in dose prescription. Radiotherapy practices among member groups of the GCIG are similar in terms of both doses and use of chemotherapy.

  15. SU-E-T-124: Dosimetric Comparison of HDR Brachytherapy and Intensity Modulated Proton Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Wu, J [Purdue University, West Lafayette, IN (United States); Wu, H [IUPUI, Indianapolis, IN (United States); Das, I [Indiana University- School of Medicine, Indianapolis, IN (United States)

    2014-06-01

    Purpose: Brachytherapy is known to be able to deliver more radiation dose to tumor while minimizing radiation dose to surrounding normal tissues. Proton therapy also provides superior dose distribution due to Bragg peak. Since both HDR and Intensity Modulated Proton Therapy (IMPT) are beneficial for their quick dose drop off, our goal in this study is to compare the pace of dose gradient drop-off between HDR and IMPT plans based on the same CT image data-set. In addition, normal tissues sparing were also compared among HDR, IMPT and SBRT. Methods: Five cervical cancer cases treated with EBRT + HDR boost combination with Tandem and Ovoid applicator were used for comparison purpose. Original HDR plans with prescribed dose of 5.5 Gy x 5 fractions were generated and optimized. The 100% isodose line of HDR plans was converted to a dose volume, and treated as CTV for IMPT and SBRT planning. The same HDR CT scans were also used for IMPT plan and SBRT plan for direct comparison. The philosophy of the IMPT and SBRT planning was to create the same CTV coverage as HDR plans. All three modalities treatment plans were compared to each other with a set of predetermined criteria. Results: With similar target volume coverage in cervix cancer boost treatment, HDR provides a slightly sharper dose drop-off from 100% to 50% isodose line, averagely in all directions compared to IMPT. However, IMPT demonstrated more dose gradient drop-off at the junction of the target and normal tissues by providing more normal tissue sparing and superior capability to reduce integral dose. Conclusion: IMPT is capable of providing comparable dose drop-off as HDR. IMPT can be explored as replacement for HDR brachytherapy in various applications.

  16. 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.

  17. Radiotherapy indications - rectum cancer

    International Nuclear Information System (INIS)

    2009-05-01

    This document is addressed to oncologists radiotherapists and to any health professional concerned by rectum cancer treatment. Rectum cancer therapy is based on various technical procedures including surgery, radiotherapy and systemic treatments defined for each patient according to his clinical situation. This document precises the specific situations where radiotherapy can be employed. However, the radiotherapy decision must be taken with respect to other therapeutic alternatives. Such a decision must be validated and must be the object of a discussion in the framework of a pluri-disciplinary consultation. (J.S.)

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

    International Nuclear Information System (INIS)

    2016-01-01

    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

  19. 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.

  20. Characteristics of hearing loss in HDR (hypoparathyroidism, sensorineural deafness, renal dysplasia) syndrome

    NARCIS (Netherlands)

    van Looij, Marjolein A. J.; Meijers-Heijboer, Hanne; Beetz, Rolf; Thakker, Rajesh V.; Christie, Paul T.; Feenstra, Lou W.; van Zanten, Bert G. A.

    2006-01-01

    Haploinsufficiency of the zinc finger transcription factor GATA3 causes the triad of hypoparathyroidism, deafness and renal dysplasia, known by its acronym HDR syndrome. The purpose of the current study was to describe in detail the auditory phenotype in human HDR patients and compare these to

  1. TU-C-201-01: Clinical Implementation of HDR: A New User’s Perspective

    Energy Technology Data Exchange (ETDEWEB)

    Al-Hallaq, H. [The University of Chicago (United States)

    2015-06-15

    Recent use of HDR has increased while planning has become more complex often necessitating 3D image-based planning. While many guidelines for the use of HDR exist, they have not kept pace with the increased complexity of 3D image-based planning. Furthermore, no comprehensive document exists to describe the wide variety of current HDR clinical indications. This educational session aims to summarize existing national and international guidelines for the safe implementation of an HDR program. A summary of HDR afterloaders available on the market and their existing applicators will be provided, with guidance on how to select the best fit for each institution’s needs. Finally, the use of checklists will be discussed as a means to implement a safe and efficient HDR program and as a method by which to verify the quality of an existing HDR program. This session will provide the perspective of expert HDR physicists as well as the perspective of a new HDR user. Learning Objectives: Summarize national and international safety and staffing guidelines for HDR implementation Discuss the process of afterloader and applicator selection for gynecologic, prostate, breast, interstitial, surface treatments Learn about the use of an audit checklist tool to measure of quality control of a new or existing HDR program Describe the evolving use of checklists within an HDR program.

  2. Computer-assisted dosimetry in the radiotherapy of cancer of the cervix

    International Nuclear Information System (INIS)

    Calaguas, M.J.C.; Rodriguez, L.V.; Vito Cruz, E.Q.; Legaspi, G.C.; De Luna, R.M.; Hermoso, T.M.; Razon, E.C.; Madrid, E.T.; Viray, R.G.

    1992-01-01

    Cancer of the cervix is the third leading cause of cancer in the Philippines. The Department of Radiotherapy of the Jose R. Reyes Memorial Medical Center has participated in the Regional Coordinated Research project sponsored by the International Atomic Energy Agency (IAEA) to undertake a study to compare computer treatment planning and manual calculations in radiotherapy of the cancer of the cervix; and to perform actual measurements on bladder and rectal points using TLDs. Twenty-seven patients with Stage II-B to III-B were included in the study. External beam teletherapy of 40 Gy without shielding for 4 weeks and 50 Gy with blocks plus brachytherapy of 20-40 Gy were given using LDR or HDR machine. Point A, bladder and rectal points were defined following ICRU 38 recommendations. The results showed dose calculations between commercially available computers and IAEA - provided computers agree to within 20%. Results of TLD measurement in bladder and rectum have shown wide range of variation. (author). 3 refs.; 4 tabs.; 8 figs

  3. : 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

  4. 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.

  5. HDR brachytherapy for superficial non-melanoma skin cancers

    International Nuclear Information System (INIS)

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

    2013-01-01

    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. 36Gy, prescribed to between 3 to 4mm, was given in daily 3Gy 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 36Gy over 2 weeks to superficial NMSC using HDR brachytherapy is well tolerated and provides a high local control rate without significant toxicity.

  6. Cost modelling of electricity-producing hot dry rock (HDR) geothermal systems in the United Kingdom

    International Nuclear Information System (INIS)

    Doherty, P.; Harrison, R.

    1995-01-01

    A detailed and comprehensive cost model for Hot Dry Rock (HDR) electricity producing systems has been developed in this study. The model takes account of the major aspects of the HDR system, parameterized in terms of the main physical and cost parameters of the resource and the utilization system. A doublet configuration is assumed, and the conceptual HDR system which is defined in the study is based upon the UK Department of Energy (DEn) HDR geothermal R and D programme. The model has been used to calculate the costs of HDR electricity for a UK defined base case which represents a consensus view of what might be achieved in Cornwall in the long term. At 14.2 p/kWh (1988 costs) this cost appears to be unacceptably high. A wide-ranging sensitivity study has also been carried out on the main resource, geometrical, and operational parameters of the HDR system centred around the UK base case. The sensitivity study shows the most important parameters to be thermal gradient and depth. The geometrical arrangement and the shape of the reservoir constitute major uncertainties in HDR systems. Their effect on temperature has a major influence on system performance, and therefore a range of theoretically possible geometries have been studied and the importance of geometrical effects on HDR electricity costs assessed. The most cost effective HDR arrangement in terms of optimized volumes and flow rates has been investigated for a world-wide range of thermal settings. The main conclusions from this study suggests that for HDR electricity to be economic, thermal gradients of 55 o C/km and above, well depths of 5 km or less, and production fluid temperatures of 210 o C and above are required. (UK)

  7. Quality indicators for prostate radiotherapy: are patients disadvantaged by receiving treatment in a 'generalist' centre?

    Science.gov (United States)

    Freeman, Amanda R; Roos, Daniel E; Kim, Laurence

    2015-04-01

    The purpose of this retrospective review was to evaluate concordance with evidence-based quality indicator guidelines for prostate cancer patients treated radically in a 'generalist' (as distinct from 'sub-specialist') centre. We were concerned that the quality of treatment may be lower in a generalist centre. If so, the findings could have relevance for many radiotherapy departments that treat prostate cancer. Two hundred fifteen consecutive patients received external beam radiotherapy (EBRT) and/or brachytherapy between 1.10.11 and 30.9.12. Treatment was deemed to be in line with evidence-based guidelines if the dose was: (i) 73.8-81 Gy at 1.8-2.0 Gy/fraction for EBRT alone (eviQ guidelines); (ii) 40-50 Gy (EBRT) for EBRT plus high-dose rate (HDR) brachytherapy boost (National Comprehensive Cancer Network (NCCN) guidelines); and (iii) 145 Gy for low dose rate (LDR) I-125 monotherapy (NCCN). Additionally, EBRT beam energy should be ≥6 MV using three-dimensional conformal RT (3D-CRT) or intensity-modulated RT (IMRT), and high-risk patients should receive neo-adjuvant androgen-deprivation therapy (ADT) (eviQ/NCCN). Treatment of pelvic nodes was also assessed. One hundred four high-risk, 84 intermediate-risk and 27 low-risk patients (NCCN criteria) were managed by eight of nine radiation oncologists. Concordance with guideline doses was confirmed in: (i) 125 of 136 patients (92%) treated with EBRT alone; (ii) 32 of 34 patients (94%) treated with EBRT + HDR BRT boost; and (iii) 45 of 45 patients (100%) treated with LDR BRT alone. All EBRT patients were treated with ≥6 MV beams using 3D-CRT (78%) or IMRT (22%). 84%, 21% and 0% of high-risk, intermediate-risk and low-risk patients received ADT, respectively. Overall treatment modality choice (including ADT use and duration where assessable) was concordant with guidelines for 176/207 (85%) of patients. The vast majority of patients were treated concordant with evidence-based guidelines suggesting that

  8. Computed versus measured response of HDR reactor building in large scale shaking tests

    International Nuclear Information System (INIS)

    Werkle, H.; Waas, G.

    1987-01-01

    The earthquake resistant design of NPP structures and their installations is commonly based on linear analysis methods. Nonlinear effects, which may occur during strong earthquakes, are approximately accounted for in the analysis by adjusting the structural damping values. Experimental investigations of nonlinear effects were performed with an extremely heavy shaker at the decommissioned HDR reactor building in West Germany. The tests were directed by KfK (Nuclear Research Center Karlsruhe, West Germany) and supported by several companies and institutes from West Germany, Switzerland and the USA. The objective was the dynamic repsonse behaviour of the structure, piping and components to strong earthquake-like shaking including nonlinear effects. This paper presents some results of safety analyses and measurements, which were performed prior and during the test series. It was intended to shake the building up to a level where only a marginal safety against global structural failure was left

  9. 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.

  10. Surveillance after prostate cancer radiotherapy

    International Nuclear Information System (INIS)

    Supiot, S.; Rio, E.; Clement-Colmou, K.; Bouchot, O.; Rigaud, J.

    2011-01-01

    Follow-up after prostate cancer radiotherapy aims at detecting local or metastatic relapse, as well as long-term toxicity, requiring adapted treatments. Several scientific societies have published guidelines including clinical, biological and imaging recommendations. More data suggest a role for aggressive salvage therapy in case of local failure following radiotherapy. An adequate follow-up is required for the sake of patients' safety, i.e. to a posteriori validate dose constraints and radiation technique in each radiotherapy department. (authors)

  11. 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.

  12. Fast exposure time decision in multi-exposure HDR imaging

    Science.gov (United States)

    Piao, Yongjie; Jin, Guang

    2012-10-01

    Currently available imaging and display system exists the problem of insufficient dynamic range, and the system cannot restore all the information for an high dynamic range (HDR) scene. The number of low dynamic range(LDR) image samples and fastness of exposure time decision impacts the real-time performance of the system dramatically. In order to realize a real-time HDR video acquisition system, this paper proposed a fast and robust method for exposure time selection in under and over exposure area which is based on system response function. The method utilized the monotony of the imaging system. According to this characteristic the exposure time is adjusted to an initial value to make the median value of the image equals to the middle value of the system output range; then adjust the exposure time to make the pixel value on two sides of histogram be the middle value of the system output range. Thus three low dynamic range images are acquired. Experiments show that the proposed method for adjusting the initial exposure time can converge in two iterations which is more fast and stable than average gray control method. As to the exposure time adjusting in under and over exposed area, the proposed method can use the dynamic range of the system more efficiently than fixed exposure time method.

  13. 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.

  14. Seismic investigations of the HDR Safety Program. Summary report

    International Nuclear Information System (INIS)

    Malcher, L.; Schrammel, D.; Steinhilber, H.; Kot, C.A.

    1994-08-01

    The primary objective of the seismic investigations, performed at the HDR facility in Kahl/Main, FRG was to validate calculational methods for the seismic evaluation of nuclear-reactor systems, using experimental data from an actual nuclear plant. Using eccentric mass shaker excitation the HDR soil/structure system was tested to incipient failure, exhibiting highly nonlinear response and demonstrating that structures not seismically designed can sustain loads equivalent to a design basin earthquake (DBE). Load transmission from the structure to piping/equipment indicated significant response amplifications and shifts to higher frequencies, while the response of tanks/vessels depended mainly on their support conditions. The evaluation of various piping support configurations demonstrated that proper system design (for a given spectrum) rather than number of supports or system stiffness is important to limiting pipe greens. Piping at loads exceeding the DBE eightfold still had significant margins and failure is improbable inspite of multiple support failures. The mean value for pipe damping, even under extreme loads, was found to be about 4%. Comparison of linear and nonlinear computational results with piping response measurements showed that predictions have a wide scatter and do not necessarily yield conservative responses underpredicting, in particular, peak support forces. For the soil/structure system the quality of the predictions did not depend so much on the complexity of the modeling, but rather on whether the model captured the salient features and nonlinearities of the system

  15. Prostate HDR brachytherapy catheter displacement between planning and treatment delivery

    International Nuclear Information System (INIS)

    Whitaker, May; Hruby, George; Lovett, Aimee; Patanjali, Nitya

    2011-01-01

    Background and purpose: HDR brachytherapy is used as a conformal boost for treating prostate cancer. Given the large doses delivered, it is critical that the volume treated matches that planned. Our outpatient protocol comprises two 9 Gy fractions, two weeks apart. We prospectively assessed catheter displacement between CT planning and treatment delivery. Materials and methods: Three fiducial markers and the catheters were implanted under transrectal ultrasound guidance. Metal marker wires were inserted into 4 reference catheters before CT; marker positions relative to each other and to the marker wires were measured from the CT scout. Measurements were repeated immediately prior to treatment delivery using pelvic X-ray with marker wires in the same reference catheters. Measurements from CT scout and film were compared. For displacements of 5 mm or more, indexer positions were adjusted prior to treatment delivery. Results: Results are based on 48 implants, in 25 patients. Median time from planning CT to treatment delivery was 254 min (range 81–367 min). Median catheter displacement was 7.5 mm (range −2.9–23.9 mm), 67% of implants had displacement of 5 mm or greater. Displacements were predominantly caudal. Conclusions: Catheter displacement can occur in the 1–3 h between the planning CT scan and treatment. It is recommended that departments performing HDR prostate brachytherapy verify catheter positions immediately prior to treatment delivery.

  16. FZUImageReg: A toolbox for medical image registration and dose fusion in cervical cancer radiotherapy.

    Directory of Open Access Journals (Sweden)

    Qinquan Gao

    Full Text Available The combination external-beam radiotherapy and high-dose-rate brachytherapy is a standard form of treatment for patients with locally advanced uterine cervical cancer. Personalized radiotherapy in cervical cancer requires efficient and accurate dose planning and assessment across these types of treatment. To achieve radiation dose assessment, accurate mapping of the dose distribution from HDR-BT onto EBRT is extremely important. However, few systems can achieve robust dose fusion and determine the accumulated dose distribution during the entire course of treatment. We have therefore developed a toolbox (FZUImageReg, which is a user-friendly dose fusion system based on hybrid image registration for radiation dose assessment in cervical cancer radiotherapy. The main part of the software consists of a collection of medical image registration algorithms and a modular design with a user-friendly interface, which allows users to quickly configure, test, monitor, and compare different registration methods for a specific application. Owing to the large deformation, the direct application of conventional state-of-the-art image registration methods is not sufficient for the accurate alignment of EBRT and HDR-BT images. To solve this problem, a multi-phase non-rigid registration method using local landmark-based free-form deformation is proposed for locally large deformation between EBRT and HDR-BT images, followed by intensity-based free-form deformation. With the transformation, the software also provides a dose mapping function according to the deformation field. The total dose distribution during the entire course of treatment can then be presented. Experimental results clearly show that the proposed system can achieve accurate registration between EBRT and HDR-BT images and provide radiation dose warping and fusion results for dose assessment in cervical cancer radiotherapy in terms of high accuracy and efficiency.

  17. Gene therapy and radiotherapy in malignant tumor

    International Nuclear Information System (INIS)

    Zhang Yaowen; Cao Yongzhen; Li Jin; Wang Qin

    2008-01-01

    Tumor treatment is one of the most important fields in medical research. Nowadays, a novel method which is combined gene therapy with radiotherapy plays an important role in the field of cancer research, and mainly includes immune gene therapy combined with radiotherapy, suicide gene therapy or tumor suppressor gene therapy combined with radiotherapy, antiangiogenesis gene therapy combined with radiotherapy and protective gene therapy combined with radiotherapy based on the technical features. This review summarized the current status of combined therapies of gene therapy and radiotherapy and possible mechanism. (authors)

  18. External audit in radiotherapy dosimetry

    International Nuclear Information System (INIS)

    Thwaites, D.I.; Western General Hospital, Edinburgh

    1996-01-01

    Quality audit forms an essential part of any comprehensive quality assurance programme. This is true in radiotherapy generally and in specific areas such as radiotherapy dosimetry. Quality audit can independently test the effectiveness of the quality system and in so doing can identify problem areas and minimize their possible consequences. Some general points concerning quality audit applied to radiotherapy are followed by specific discussion of its practical role in radiotherapy dosimetry, following its evolution from dosimetric intercomparison exercises to routine measurement-based on-going audit in the various developing audit networks both in the UK and internationally. Specific examples of methods and results are given from some of these, including the Scottish+ audit group. Quality audit in radiotherapy dosimetry is now well proven and participation by individual centres is strongly recommended. Similar audit approaches are to be encouraged in other areas of the radiotherapy process. (author)

  19. Preliminary results of intersticial HDR brachytherapy in association with conservative surgery for soft tissue sarcomas

    International Nuclear Information System (INIS)

    Pellizzon, A.C.A; Ferrigno, R.; Trippe, N.; Novaes, P.; Salvajoli, J.V.; Fogareli, R.; Maja, M.A.C.; Baraldi, H.

    1996-01-01

    From january 1994 to january 1995 seven patients were treated with conservative surgery in association to postoperative HDR brachytherapy through Micro-Selectron HDR. Four patients were male and three female, the ages ranged from 20 to 60 years old and the main site of the tumor were at the extremities and just one had a perineal lesion. The follow up ranged from 4 to 24 months. Most of the implants were done through single plane technic. Definition of the treatment volume was based on CT scans and metallic clips inserted during the surgery. The prescribed dose was at 10mm from the implant plane. The patient with perineal lesion had a volumetric implant and the dose prescription was based on Paris System, in which the total volume of the tumor bed must be included in a 85% isodose curve. The number of catheters used ranged from 6 to 14 and the active length from 20 to 150mm, placed intraoperatively. The volumetric implant was performed through perineal template to guide the needles in number of nine and an active length of 60mm. The prescribed dose ranged from 20 to 25Gy when associated with EBRT and 30 to 35Gy when brachytherapy alone was used. Results: All patients had local control. Acute complications were observed only in the skin, limited to mild erytema and dry descanation. Conclusions: Although the number of the patients is small, this procedure has been shown to be effective in local control when associated to conservative surgery, can be easily and safely done and gives the possibilities of dose optimization

  20. 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.

  1. 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

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

    DEFF Research Database (Denmark)

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

    2010-01-01

    Estimation and detection of the hemodynamic response (HDR) are of great importance in functional MRI (fMRI) data analysis. In this paper, we propose the use of three H-infinity adaptive filters (finite memory, exponentially weighted, and timevarying) for accurate estimation and detection of the HDR......-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....

  3. Finite element study of a HDR-RPV-section including a nozzle under thermal shock transient

    Energy Technology Data Exchange (ETDEWEB)

    Roos, E [Stuttgart Univ. (Germany); Katzenmeier, G [Forschungszentrum Juelich GmbH (Germany); Wanner, R; Mercier, O [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1988-12-31

    This document presents a finite element study of a reactor pressure vessel section under thermal stresses. The strength properties of the vessel walls are studied as well as cracks due to the thermo-shock transient. (TEC). 6 refs.

  4. Commissioning and clinical implementation of HDR brachytherapy in El Salvador

    International Nuclear Information System (INIS)

    Morales Lopez, Jorge Luis; Castillo, Luis Frank; Castillo Bahi, Ramon del

    2009-01-01

    The Gynecologic Cancer is one of the best known malignancies in different countries of the world, with a high incidence in developing countries. In the treatment of this disease have been used multiple treatment arms among which is the high rate brachytherapy (HDR). The IAEA has put much emphasis on supporting all programs to treat this disease and in this context within the project 'Human Resource Development and Nuclear Technology Support', collaborated with the dispatch of experts on mission ELS0006 01 'Assistance to the ICES in HDR brachytherapy initiating Treatments at the Cancer Institute of El Salvador 'Dr. Narciso Diaz Bazan' in San Salvador, El Salvador. The process of commissioning and implementing clinical service Brachytherapy High Dose Rate (HDR BT) is a relatively complex process that begins with the formation of functional and technical service, based on flow patients to be treated, availability of local technological capability to install, and culminates with the preparation and implementation of protocols. Experts involved in the implementation of this service divided this task in stages organized chronologically: 1st. Study of existing infrastructure and level of training of technical personnel available, 2nd. Proposal and application of amendments in order to adapt the facility to the planned patient flow and optimal use of technological infrastructure, 3rd. Establishment of the process of securing the disposable waste materials and not required, 4th. Performance of tests of physical commissioning clinical dosimetry and instrumentation unit, surgical and therapeutic, 5th. Training of technical personnel, 6th. Preparation of clinical protocol and 7th. Initiation and development of treatment for patients. All these steps are carried out with the integration and consensus of the entire multidisciplinary team that makes up the service and with the support of the administration as a prerequisite. Within two weeks the service was modified according to

  5. [Current status and potential perspectives in classical radiotherapy technology].

    Science.gov (United States)

    Dabić-Stanković, Kata M; Stanković, Jovan B; Radosević-Jelić, Ljiljana M

    2004-01-01

    After purchase of radiotherapy equipment in 2003, classic radiation therapy in Serbia will reach the highest world level. In order to define the highest standards in radiation technology, we analyzed the current status and potential perspectives of radiation therapy. An analysis of present situation in the USA, assumed as the most developed in the world, was done. Available data, collected in the last 3 years (equipment assortment, therapy modalities, workload and manpower) for 284 radiotherapy centers, out of potential 2050, were analyzed. Results were presented as crude percentage and matched to point current status. The analysis showed that CLINAC accelerators are the most popular (82.7%), as well as, ADAC (43.7%) and Focus (CMS) (27.4%) systems for therapy planning. Movement towards virtual simulation is evident (59.3%), although classic "simulation" is not fully eliminated from the radiotherapy chain. The most popular brachytherapy afterloader is Microselectron HDR (71%). About 64.4% centers use IMPAC communication/verification/record system that seems more open than Varis. All centers practice modern radiotherapy modalities and techniques (CPRT, IMRT, SRS/SRT, TBI, IORT, IVBHRT, HDR BHRT, etc.). CT and MRI availability is out of question, but PET is available in 3% of centers, however this percentage is rapidly growing. Up to 350 new patients per year are treated by one accelerator (about 35 pts. a day). Centers are relatively small and utilize 2-3 accelerators on average. Average FTE staffing norm is 4 radiation oncologists, 2-3 medical radiotherapy physicists, about 3 certified medical dosimetrists and about 6 radiotherapy technologists. In the past 5 years relative stagnation in classic radiotherapy has been observed. In spite of substantial investments in technology and consequent improvements, as well as wide introduction of computers in radiotherapy, radiotherapy results have not changed significantly. Vendor developement strategies do not point that

  6. Commissioning of a well type chamber for HDR and LDR brachytherapy applications: a review of methodology and outcomes.

    Science.gov (United States)

    Mukwada, Godfrey; Neveri, Gabor; Alkhatib, Zaid; Waterhouse, David K; Ebert, Martin

    2016-03-01

    For safe and accurate dose delivery in brachytherapy, associated equipment is subject to commissioning and ongoing quality assurance (QA). Many centres depend on the use of a well-type chamber ('well chamber') for performing brachytherapy dosimetry. Documentation of well chamber commissioning is scarce despite the important role the chamber plays in the whole brachytherapy QA process. An extensive and structured commissioning of the HDR 1000 plus well chamber (Standard Imaging Inc, Middleton WI) for HDR and LDR dosimetry was undertaken at Sir Charles Gairdner Hospital. The methodology and outcomes of this commissioning is documented and presented as a guideline to others involved in brachytherapy. The commissioning tests described include mechanical integrity, leakage current, directional dependence, response, length of uniform response, the influence of insert holders, ion collection efficiency, polarity effect, accuracy of measured air kerma strength (S(K)) or reference air kerma rate (K(R)) and baseline setting (for ongoing constancy checks). For the HDR 1000 plus well chamber, some of the insert holders modify the response curve. The measured sweet length was 2.5 cm which is within 0.5% of that specified by the manufacturer. Correction for polarity was negligible (0.9999) and ion recombination was small (0.9994). Directional dependence was small (less than 0.2%) and leakage current was negligible. The measured K(R) for (192)Ir agreed within 0.11% compared with a second well chamber of similar model and was within 0.5% of that determined via a free-in-air measurement method. Routine constancy checks over a year agreed with the baseline within 0.4%.

  7. HDR flood-water storage-tank modal vibration tests

    International Nuclear Information System (INIS)

    Gorman, V.W.; Thinnes, G.L.

    1983-01-01

    Modal vibration tests were conducted by EG and G Idaho on two vessels located at West Germany's Heissdampfreaktor (HDR) facility which is 25 kilometers east of Frankfurt. The tests were performed during May and June 1982 for the US Nuclear Regulatory Commission (NRC) as part of their cooperative effort with Kernforschungszentrum Karlsruhe (KfK) of West Germany. The primary purpose for performing this task was to determine modal properties (frequencies, mode shapes and associated damping ratios) in order to eventually provide guidelines for standards development by the NRC in modeling similar vessels. One of the vessels tested was a flood water storage tank (FWST) for empty, half full and full water conditions. The FWST was excited randomly with an electromagnetic shaker and by impulsive hammer blows. Excitation or input forces together with measured vessel responses were processed by a digital modal analyzer and stored on magnetic disks for subsequent evaluation

  8. Remote Afterloading High Dose Rate (HDR) Endobronchial Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Hyesook; Choi, Eun Kyung; Yi, Byong Yong; Kim, Won Dong; Kim, Woo Sung; Koh, Youn Suck [Ulsan University College of Medicine, Seoul (Korea, Republic of)

    1991-12-15

    Authors described the remote afterloading endobronchial brachytherapy (EBBT) technique using the microSelectron HDR Ir-192 and the Asan Medical Center experience. Total 28 EBBT in 9 patients were performed since November 1989 and 24 EBBT in 8 patients were employed for palliation and 3 EBBT in 1 patient was treated curatively. Authors observed a significant relief of obstructive symptom with tumor regression in 7 patients out of 8 who were treated palliatively but one of them died of pulmonary congestion in 3 weeks after EBBT. One patient with prior therapy of extensive electrocautery expired within 1 day after 2nd EBBT procedure with massive hemorrhage from the lesion. EBBT procedure has been tolerable and can be performed as an outpatient.

  9. Remote Afterloading High Dose Rate (HDR) Endobronchial Brachytherapy

    International Nuclear Information System (INIS)

    Chang, Hyesook; Choi, Eun Kyung; Yi, Byong Yong; Kim, Won Dong; Kim, Woo Sung; Koh, Youn Suck

    1991-01-01

    Authors described the remote afterloading endobronchial brachytherapy (EBBT) technique using the microSelectron HDR Ir-192 and the Asan Medical Center experience. Total 28 EBBT in 9 patients were performed since November 1989 and 24 EBBT in 8 patients were employed for palliation and 3 EBBT in 1 patient was treated curatively. Authors observed a significant relief of obstructive symptom with tumor regression in 7 patients out of 8 who were treated palliatively but one of them died of pulmonary congestion in 3 weeks after EBBT. One patient with prior therapy of extensive electrocautery expired within 1 day after 2nd EBBT procedure with massive hemorrhage from the lesion. EBBT procedure has been tolerable and can be performed as an outpatient

  10. Risk of second non-breast cancer among patients treated with and without postoperative radiotherapy for primary breast cancer: A systematic review and meta-analysis of population-based studies including 522,739 patients

    DEFF Research Database (Denmark)

    Grantzau, Trine; Overgaard, Jens

    2016-01-01

    -irradiated women. Irradiated patients had an overall increased risk of second non-breast cancer, with a SIR of 1.23 (95% confidence interval [CI] 1.12-1.36). For non-irradiated patients the SIR was 1.08 (95% CI, 1.03-1.13). For irradiated patients the incidence of second cancers including the lung, esophagus......, thyroid and connective tissues progressively increased over time, peaking at 10-15years following breast cancer diagnosis. Summary estimates at ⩾15years after breast cancer irradiation were 1.91 for lung, 2.71 for esophagus, 3.15 for thyroid and 6.54 at ⩾10years for second sarcomas. Non......-irradiated patients had no increased risk of second lung or esophagus cancer, neither overall nor over time. For non-irradiated patients' risk of second thyroid cancer (SIR 1.21) and sarcomas (SIR 1.42) were increased overall, but with no remaining risk ⩾10 after breast cancer. CONCLUSION: Radiotherapy for breast...

  11. Cost modelling of electricity producing hot dry rock (HDR) geothermal systems in the UK

    International Nuclear Information System (INIS)

    Doherty, P.S.

    1992-03-01

    A detailed and comprehensive cost model for Hot Dry Rock (HDR) electricity producing systems has been developed in this study. The model takes account of the major aspects of the HDR system, parameterized in terms of the main physical and cost parameters of the resource and the utilization system. A doublet configuration is assumed, and the conceptual HDR system which is defined in the study is based upon the UK Department of Energy (DEn) HDR geothermal R and D programme. The model has been used to calculate the costs of HDR electricity for a UK defined base case which represents a consensus view of what might be achieved in Cornwall in the long term. At 14.2 p/kWh (1988 costs) this cost appears to be unacceptably high. A wide-ranging sensitivity study has also been carried out on the main resource, geometrical, and operational parameters of the HDR system centred around the UK base case. The sensitivity study shows the most important parameters to be thermal gradient and depth. (Author)

  12. Treatment results of radical radiotherapy in uterine cervix cancer

    Energy Technology Data Exchange (ETDEWEB)

    Huh, Seung Jae; Kim, Bo Kyong; Lim, Do Hoon; Shin, Seong Soo; Lee, Jeong Eun; Kang, Min Kyu; Ahn, Yong Chan [Samsung Medical center, sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2002-09-15

    This study was conducted to evaluate the treatment results, prognostic factors, and complication rates after high dose rate (HDR) brachytherapy in patients with uterine cervix cancer who were treated with curative aim. Of 269 cervix cancer patients treated at the department of radiation oncology, Samsung Medical Center from September 1994 to July 1998, the 106 who were treated with radical radiotherapy were analyzed. The median age was 61 years (range 22 to 89). All patients except 4 with carcinoma in situ (CIS) were given external beam radiotherapy (range 30.6 {approx} 50.4 Gy to whole pelvis) and HDR brachytherapy. The common regimens of HDR brachytherapy were a total dose of 24 {approx} 28 Gy with 6 {approx} 7 fractions to point A at two fractions per week. The median overall treatment time was 55 days (range 44 to 104) in patients given both external beam radiotherapy and HDR brachytherapy. Early response of radiotherapy were evaluated by gynecologic examination and follow-up MRI 1 month after radiotherapy. Treatment responses were complete remission in 72 patients, partial response in 33 and no response in 1. The overall survival (OS) rate of all patients was 82%, and 73%, and the disease free survival (DFS) rate was 72%, and 69%, at 3, and 5 years, respectively. The pelvic control rate (PCR) was 79% at both 3 and 5 years. According to the FIGO stage, 3 and 5 year OS were 100% and 50% in CIS/IA, 100% in 100% in IB, 83% and 69% in IIA, 87% and 80% in IIB, and 62% and 62% in III, respectively. The 3 year OS in 4 patients with stage IVA was 100%. Three-year DFS were 80% in CIS/IA, 88% in IB, 100% in IIA, 64% in IIB, 58% in III, and 75% in IVA. Three-year PCR were 100% in CIS/IA, 94% in IB, 100% in IIA, 84% in IIB, 69% in III, and 50% in IVA. By univariate analysis, FIGO stage and treatment response were significant factors for OS. The significant factors for DFS were age, FIGO stage, treatment response and overall treatment time (OTT). For pelvic control rate

  13. Investigation of normal tissue complication probabilities in prostate and partial breast irradiation radiotherapy techniques

    International Nuclear Information System (INIS)

    Bezak, E.; Takam, R.; Bensaleh, S.; Yeoh, E.; Marcu, L.

    2011-01-01

    Full text: Normal- Tissue-Complication Probabilities of rectum, bladder and urethra following various radiation techniques for prostate cancer were evaluated using the relative-seriality and Lyman models. NTCPs of lungs, heart and skin, their dependence on sourceposition, balloon-deformation were also investigated for HDR mammosite brachytherapy. The prostate treatment techniques included external three dimentional conformal-radiotherapy, Low-Dose-Rate brachytherapy (1-125), High-Dose-Rate brachytherapy (Ir-I92). Dose- Volume-Histograms of critical structures for prostate and breast radiotherapy, retrieved from corresponding treatment planning systems, were converted to Biological Effective Dose (BEffD)-based and Equivalent Dose(Deq)-based DVHs to account for differences in radiation delivery and fractionation schedule. Literature-based model parameters were used to calculate NTCPs. Hypofractionated 3D-CRT (2.75 Gy/fraction, total dose 55 Gy) NTCPs of rectum, bladder and urethra were less than those for standard fractionated 4-field 3D-CRT (2-Gy/fraction, 64 Gy) and dose-escalated 4- and 5-field 3D-CRT (74 Gy). Rectal and bladder NTCPs (5.2% and 6.6%) following the dose-escalated 4-field 3D-CRT (74 Gy) were the highest among analyzed techniques. The average NTCP for rectum and urethra were 0.6% and 24.7% for LDRBT and 0.5% and 11.2% for HDR-BT. For Mammosite, NTCP was estimated to be 0.1 %, 0.1 %, 1.2% and 3.5% for skin desquamation, erythema, telangiectasia and fibrosis respectively (the source positioned at the balloon centre). A 4 mm Mammosite-balloon deformation leads to overdosing of PTV regions by ∼40%, resulting in excessive skin dose and increased NTCP. Conclusions Prostate brachytherapy resulted in NTCPs lower compared to external beam techniques. Mammosite-brachytherapy resulted in no heart/lung complications regardless of balloon deformation. However, 4 mm deformation caused 0.6% increase in tissue fibrosis NTCP.

  14. Patterns of Radiotherapy Practice for Patients With Cervical Cancer (1999-2001): Patterns of Care Study in Japan

    International Nuclear Information System (INIS)

    Toita, Takafumi; Kodaira, Takeshi; Shinoda, Atsunori; Uno, Takashi; Akino, Yuichi; Mitsumori, Michihide; Teshima, Teruki

    2008-01-01

    Purpose: To describe the patterns of definitive radiotherapy practice for patients with uterine cervical cancer from 1999 to 2001 in Japan. Methods and Materials: The Japanese Patterns of Care Study (JPCS) working group conducted a third extramural audit survey of 68 institutions and collected specific information on 324 cervical cancer patients treated with definitive radiotherapy. Results: Almost all patients (96%) were treated with whole pelvic radiotherapy using opposing anteroposterior fields (87%). A midline block was used in 70% of the patients. Intracavitary brachytherapy (ICBT) was applied in 82% of cases. Most patients (89%) were treated with high-dose rate (HDR) ICBT. Calculation of doses to organs at risk (ICRU 38) was performed for rectum in 25% of cases and for bladder in 18% of cases. Only 3% of patients were given intravenous conscious sedation during ICBT applicator insertions. The median total biologically effective dose at point A (EBRT+ICBT) was 74 Gy 10 in cases treated with HDR-ICBT. There was no significant difference in total biologically effective dose between stages. The median overall treatment time was 47 days. Concurrent chemoradiation was applied in 17% of patients. Conclusions: This study describes the general patterns of radiotherapy practice for uterine cervical cancer in Japan. Although methods of external radiotherapy seemed to be appropriate, there was room for improvement in ICBT practice, such as pretreatment. A substantial difference in total radiotherapy dose between Japan and the United States was observed

  15. Radiotherapy; Strahlentherapie

    Energy Technology Data Exchange (ETDEWEB)

    Wannenmacher, M. [Heidelberg Univ., Mannheim (Germany). Abt. fuer Klinische Radiologie; Debus, J. [Univ. Heidelberg (Germany). Abt. Radioonkologie und Strahlentherapie; Wenz, F. (eds.) [Universitaetsklinikum Mannheim (Germany). Klinik fuer Strahlentherapie und Radioonkologie

    2006-07-01

    The book is focussed on the actual knowledge on the clinical radiotherapy and radio-oncology. Besides fundamental and general contributions specific organ systems are treated in detail. The book contains the following contributions: Basic principles, radiobiological fundamentals, physical background, radiation pathology, basics and technique of brachytherapy, methodology and technique of the stereotactic radiosurgery, whole-body irradiation, operative radiotherapy, hadron therapy, hpyerthermia, combined radio-chemo-therapy, biometric clinical studies, intensity modulated radiotherapy, side effects, oncological diagnostics; central nervous system and sense organs, head-neck carcinomas, breast cancer, thorax organs, esophagus carcinoma, stomach carcinoma, pancreas carcinoma, heptabiliary cancer and liver metastases, rectal carcinomas, kidney and urinary tract, prostate carcinoma, testicular carcinoma, female pelvis, lymphatic system carcinomas, soft tissue carcinoma, skin cancer, bone metastases, pediatric tumors, nonmalignant diseases, emergency in radio-oncology, supporting therapy, palliative therapy.

  16. Is there any advantage of CT based 3-dimensional conformal planning over conventional orthogonal x-ray based planning in HDR brachytherapy in breast cancer

    International Nuclear Information System (INIS)

    Biswal, B.M.; Idris, N.R.; Zakaria, A.B.; Khairul, N.

    2003-01-01

    The conventional brachytherapy dose calculation is based on a particular brachytherapy rule or individual dosimetry based on the reconstruction of the sources from the orthogonal films. In the recent years many centers are using CT based 3D conformal brachytherapy in order to improve the dosimetric outcome of a given plan. Here we would like to present our experience on the use of both techniques to deliver HDR interstitial brachytherapy as boost in early breast cancer. From January 2001 to January 2003, we treated 4 breast cancer patients using conventional orthogonal x-rays and CT scan in 3 cases for the treatment plan. All patients received an external beam radiotherapy dose of 46 Gy in 23 fractions over 4.5 weeks to the whole breast using 6 MV photon beam. Subsequently the primary lesion was supplimented with HDR brachytherapy to a dose of 2.5 Gy BID for 3 consecutive days using a (192)Ir microSelectronHDR. The dose prescription was individualized to encompass the tumor volume with a 10 mm margin. The differences of the dosimetric outcome were compared. All patients completed above schedule of radiotherapy. The primary was implanted with single plane in 3 patients and multiplane implant in 4 patients. Orthogonal x-ray based localization was performed in 4 patients and CT scan based localization in 3 cases. Three patients were implanted single plane and 4 patients with multiplane implants with a median catheter number of 9 (range 6-14). The 3D conformal dose optimization was performed using Nucletron planning system (Plato). The mean 100% and 150% isodose volume was 67.3 cm 3 and 31.25cm 3 respectively. The identification of primary tumor volume, organ at risk, and identification of afterloading catheters were superior in CT based plan than conventional planning. CT scan based 3D conformal brachytherapy planning give better identification of tumor volume and its curvature, decrease the time to identify the sources and evaluate the radiation dose to organs at

  17. Demand for radiotherapy in Spain.

    Science.gov (United States)

    Rodríguez, A; Borrás, J M; López-Torrecilla, J; Algara, M; Palacios-Eito, A; Gómez-Caamaño, A; Olay, L; Lara, P C

    2017-02-01

    Assessing the demand for radiotherapy in Spain based on existing evidence to estimate the human resources and equipment needed so that every person in Spain has access to high-quality radiotherapy when they need it. We used data from the European Cancer Observatory on the estimated incidence of cancer in Spain in 2012, along with the evidence-based indications for radiotherapy developed by the Australian CCORE project, to obtain an optimal radiotherapy utilisation proportion (OUP) for each tumour. About 50.5 % of new cancers in Spain require radiotherapy at least once over the course of the disease. Additional demand for these services comes from reradiation therapy and non-melanoma skin cancer. Approximately, 25-30 % of cancer patients with an indication for radiotherapy do not receive it due to factors that include access, patient preference, familiarity with the treatment among physicians, and especially resource shortages, all of which contribute to its underutilisation. Radiotherapy is underused in Spain. The increasing incidence of cancer expected over the next decade and the greater frequency of reradiations necessitate the incorporation of radiotherapy demand into need-based calculations for cancer services planning.

  18. Radiotherapy apparatus

    International Nuclear Information System (INIS)

    Leung, P.M.; Webb, H.P.J.

    1985-01-01

    This invention relates to apparatus for applying intracavitary radiotherapy. In previously-known systems radioactive material is conveyed to a desired location within a patient by transporting a chain of balls pneumatically to and from an appropriately inserted applicator. According to this invention a ball chain for such a purpose comprises several radioactive balls separated by non-radioactive tracer balls of radiographically transparent material of lower density and surface hardness than the radioactive balls. The invention also extends to radiotherapy treatment apparatus comprising a storage, sorting and assembly system

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

    International Nuclear Information System (INIS)

    Gabris, F.; Zeman, J.; Valenta, J.; Gabris, F.; Selbach, H.J.

    2012-01-01

    A secondary standard of the BEV, calibrated at the PTB in terms of D w,1c m, 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 after-loader. 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 D w,1c m may improve the safety and reliability of patient treatment. (authors)

  20. A summary of the Fire Testing Program at the German HDR Test Facility

    International Nuclear Information System (INIS)

    Nowlen, S.P.

    1995-11-01

    This report provides an overview of the fire safety experiments performed under the sponsorship of the German government in the containment building of the decommissioned pilot nuclear power plant known as HDR. This structure is a highly complex, multi-compartment, multi-level building which has been used as the test bed for a wide range of nuclear power plant operation safety experiments. These experiments have included numerous fire tests. Test fire fuel sources have included gas burners, wood cribs, oil pools, nozzle release oil fires, and cable in cable trays. A wide range of ventilation conditions including full natural ventilation, full forced ventilation, and combined natural and forced ventilation have been evaluated. During most of the tests, the fire products mixed freely with the full containment volume. Macro-scale building circulation patterns which were very sensitive to such factors as ventilation configuration were observed and characterized. Testing also included the evaluation of selective area pressurization schemes as a means of smoke control for emergency access and evacuation stairwells

  1. Comparison of radiation shielding requirements for HDR brachytherapy using 169Yb and 192Ir sources

    International Nuclear Information System (INIS)

    Lymperopoulou, G.; Papagiannis, P.; Sakelliou, L.; Georgiou, E.; Hourdakis, C. J.; Baltas, D.

    2006-01-01

    169 Yb has received a renewed focus lately as an alternative to 192 Ir sources for high dose rate (HDR) brachytherapy. Following the results of a recent work by our group which proved 169 Yb to be a good candidate for HDR prostate brachytherapy, this work seeks to quantify the radiation shielding requirements for 169 Yb HDR brachytherapy applications in comparison to the corresponding requirements for the current 192 Ir HDR brachytherapy standard. Monte Carlo simulation (MC) is used to obtain 169 Yb and 192 Ir broad beam transmission data through lead and concrete. Results are fitted to an analytical equation which can be used to readily calculate the barrier thickness required to achieve a given dose rate reduction. Shielding requirements for a HDR brachytherapy treatment room facility are presented as a function of distance, occupancy, dose limit, and facility workload, using analytical calculations for both 169 Yb and 192 Ir HDR sources. The barrier thickness required for 169 Yb is lower than that for 192 Ir by a factor of 4-5 for lead and 1.5-2 for concrete. Regarding 169 Yb HDR brachytherapy applications, the lead shielding requirements do not exceed 15 mm, even in highly conservative case scenarios. This allows for the construction of a lead door in most cases, thus avoiding the construction of a space consuming, specially designed maze. The effects of source structure, attenuation by the patient, and scatter conditions within an actual treatment room on the above-noted findings are also discussed using corresponding MC simulation results

  2. Preliminary results of study comparing HDR with LDR brachytherapy for IIIb cervical cancer

    International Nuclear Information System (INIS)

    Trippe, N.; Pellizzon, A.C.A.; Novaes, P.; Salvajoli, J.V.; Fogaroli, R.; Maia, M.A.C.; Baraldi, H.; Ferrigno, R.

    1996-01-01

    Since 1992 we have been using a Micro-Selectron HDR device, working with Iridium 192 to treat the cervical cancer and some others pathologies. With a minimum follow up of 24 months, 59 patients with cervical cancer were randomizated for one of the following schedule of treatment: EBRT - 45Gy - fx 1,8Gy plus Brachytherapy 1-HDR - 36 (61%) - 4 weekly insertions of 6,0Gy at point A 2-LDR - 29 (39%) - two insertions fifteen days apart of 17,5Gy at point A EBRT was performed with a Linac 4MV, in box arrangement and parametrial complementation of dose with AP-PA fields. For Brachytherapy Fletcher Colpostats are used in association with intrauterine tamdens, in both arms. Brachyterapy starts in HDR group after ten days of the beginning of the treatment. The total time of treatment is shortened here in two weeks. LDR brachytherapy starts only after the end of EBRT. Results - local control was 61% in 12 months and 50% in 24 months for HDR group, versus 52,6% and 47,8% for LDR group. Local failures of 39% and 50% in 12 and 24 months for HDR and 47,8% and 52,8% for LDR groups respectively. Complications were restricted to rectites and cistites - 8,3% for HDR and 13% for LDR. Conclusions - HDR brachytherapy has an equivalent local control when compared to LDR, can treat a larger number of patients in a shorter period, has possibilities of dose optimizations and decrease the radiation exposure to the staff

  3. MR-based source localization for MR-guided HDR brachytherapy

    Science.gov (United States)

    Beld, E.; Moerland, M. A.; Zijlstra, F.; Viergever, M. A.; Lagendijk, J. J. W.; Seevinck, P. R.

    2018-04-01

    For the purpose of MR-guided high-dose-rate (HDR) brachytherapy, a method for real-time localization of an HDR brachytherapy source was developed, which requires high spatial and temporal resolutions. MR-based localization of an HDR source serves two main aims. First, it enables real-time treatment verification by determination of the HDR source positions during treatment. Second, when using a dummy source, MR-based source localization provides an automatic detection of the source dwell positions after catheter insertion, allowing elimination of the catheter reconstruction procedure. Localization of the HDR source was conducted by simulation of the MR artifacts, followed by a phase correlation localization algorithm applied to the MR images and the simulated images, to determine the position of the HDR source in the MR images. To increase the temporal resolution of the MR acquisition, the spatial resolution was decreased, and a subpixel localization operation was introduced. Furthermore, parallel imaging (sensitivity encoding) was applied to further decrease the MR scan time. The localization method was validated by a comparison with CT, and the accuracy and precision were investigated. The results demonstrated that the described method could be used to determine the HDR source position with a high accuracy (0.4–0.6 mm) and a high precision (⩽0.1 mm), at high temporal resolutions (0.15–1.2 s per slice). This would enable real-time treatment verification as well as an automatic detection of the source dwell positions.

  4. SU-F-BRA-04: Prostate HDR Brachytherapy with Multichannel Robotic System

    International Nuclear Information System (INIS)

    Joseph, F Maria; Podder, T; Yu, Y

    2015-01-01

    Purpose: High-dose-rate (HDR) brachytherapy is gradually becoming popular in treating patients with prostate cancers. However, placement of the HDR needles at desired locations into the patient is challenging. Application of robotic system may improve the accuracy of the clinical procedure. This experimental study is to evaluate the feasibility of using a multichannel robotic system for prostate HDR brachytherapy. Methods: In this experimental study, the robotic system employed was a 6-DOF Multichannel Image-guided Robotic Assistant for Brachytherapy (MIRAB), which was designed and fabricated for prostate seed implantation. The MIRAB has the provision of rotating 16 needles while inserting them. Ten prostate HDR brachytherapy needles were simultaneously inserted using MIRAB into a commercially available prostate phantom. After inserting the needles into the prostate phantom at desired locations, 2mm thick CT slices were obtained for dosimetric planning. HDR plan was generated using Oncetra planning system with a total prescription dose of 34Gy in 4 fractions. Plan quality was evaluated considering dose coverage to prostate and planning target volume (PTV), with 3mm margin around prostate, as well as the dose limit to the organs at risk (OARs) following the American Brachytherapy Society (ABS) guidelines. Results: From the CT scan, it is observed that the needles were inserted straight into the desired locations and they were adequately spaced and distributed for a clinically acceptable HDR plan. Coverage to PTV and prostate were about 91% (V100= 91%) and 96% (V100=96%), respectively. Dose to 1cc of urethra, rectum, and bladder were within the ABS specified limits. Conclusion: The MIRAB was able to insert multiple needles simultaneously into the prostate precisely. By controlling the MIRAB to insert all the ten utilized needles into the prostate phantom, we could achieve the robotic HDR brachytherapy successfully. Further study for assessing the system

  5. The biological basis of radiotherapy

    International Nuclear Information System (INIS)

    Steel, G.G.; Adams, G.E.; Horwich, A.

    1989-01-01

    The focus of this book is the biological basis of radiotherapy. The papers presented include: Temporal stages of radiation action:free radical processes; The molecular basis of radiosensitivity; and Radiation damage to early-reacting normal tissue

  6. Early bowel complications following radiotherapy of uterine cervix carcinoma

    International Nuclear Information System (INIS)

    Kim, Won Dong

    1999-01-01

    This study evaluated early bowel complications in cervix cancer patients, following external radiotherapy (ERT) and high dose rate intracavitary radiation (HDR ICR). Factors affecting the risk of developing early bowel complications and its incidence are analyzed and discussed. The study is the retrospective review of 66 patients who received radiotherapy at Chungbuk National University Hospital from April 1994 to December 1998. The patients underwent 41.4 or 50.4 Gy ERT according to FIGO stage and tumor size, then A point dose was boosted to 71.4 or 74.4 Gy using a remotely controlled after loading Buchler HDR ICR. The EORTC/RTOG morbidity criteria were used to grade early bowel complications, which are valid from day 1, the commencement of therapy, through day 90. The actuarial incidence, severity of complications were investigated and clinical pretreatment factors relevant to complications were found through univariate (Wilcoxon) and multivariate (Cox proportional hazard model) analysis. Of the 66 patients, 30 patients (46%) developed early bowel complications; 25 patients (38%) with grade 1 or 2, 4 patients (6%) with grade 3 and 1 patient (2%) with grade 4. The complications usually began to occur 3 weeks after the commencement of radiotherapy. The actuarial incidence of early bowel complications was 41% at 10 weeks. The early bowel complications were associated significantly with an old age and a history of previous abdomino-pelvic surgery. All three patients who had a protracted overall treatment time (about 2 weeks) due to severe bowel complication, suffered from pelvic recurrences. Forty six percent of patients experienced early bowel complications, most of which were grade 1 or 2 and relieved spontaneously or by medication. The patients with an old age or a previous surgery have a high probability of early complications and they may be less compliant with planned radiotherapy. So more careful precaution is necessary for these patients

  7. Postoperative radiotherapy for endometrial carcinoma. A retrospective analysis of 541 cases

    International Nuclear Information System (INIS)

    Haensgen, G.; Nagel, M.; Dunst, J.; Enke, H.

    1999-01-01

    Purpose: This retrospective study was designed to evaluate the role of adjuvant radiotherapy for surgically treated endometrial carcinoma. Patients and methods: From 1980 through 1988, 541 patients were treated with either intravaginal cuff irradiation with a high-dose-rate (HDR) Iridium-192 remote afterloading technique (n=294) or with combined HDR-brachytherapy and additional external pelvic irradiation to 54 Gy (n=247) after surgery for endometrical cancer. Afterloading irradiation was administered in 4 fractions 4 to 6 weeks after surgery. A dose of 30 Gy was delivered at a depth of 0,5 cm from the vaginal mucosa. Results: Patients with HDR-brachytherapy alone showed a 5-year survival of 94.3% for Stage I and 73.6% for Stage II (p=0.0007). Patients who received both brachytherapy and additional pelvic irradiation had a 5-year survival of 94.1% for Stage I, 81.1% for Stage II, 70.4% for Stage III and 46.9% for Stage IV (p=0.0001). The main predictors for survival in a multivariate analysis were stage and grading. Patients with combined readiotherapy had a local recurrence rate of 3.2%, whereas patients with brachytherapy alone who were better selected and had more favorable prognostic factors showed a recurrence rate of 2%. Low-risk patients (Stage I, Grade 1, low infiltration) in the HDR-brachytherapy group had 6 relapses, mainly caused by insufficient treatment on the basis of papillary histology. High-risk patients with poorly differential tumors, which infiltrate more than half the myometrial wall might benefit from additional external radiotherapy in terms of reduction of local recurrence and better survival. Five-year actuarial survival rate was 93.6% after combined radiotherapy vs 86.7% after brachytherapy alone. Complications were graded according to the RTOG scoring system. Severe late complications were fistulas of bladder and/or bowel, which occurred in 2.8% in the combined radiotherapy group, and 0.7% in the HDR brachytherapy group. (orig.) [de

  8. Requirements tests for QC of microSelectron-HDR

    International Nuclear Information System (INIS)

    Gesheva-Atanasova, N.; Gogova, A.; Peycheva, S.; Constantinov, B.; Ganchev, M.

    2000-01-01

    The Quality Control (QC) considers checks and measurements with the purpose of reconstruction, maintaining and increasing the quality of medical procedures and equipment. The QC tests for micro Selectron HDR afterloading machine with 192 Ir which allows more precise calculation and realisation of the tumour's dose have been created and introduced regularly in National Oncological Centre, Sofia. This paper has been cover the machine and software performance, source positioning, application equipment and radiation safety. A list of tests, their frequency, tolerance and action levels, as well as the tests' procedures have been worked out. The used methods are based on establishment of QC protocols. The documents have achieved for a certain period of time and they are available at any time. The experience shows drastically reduction of failures during medical treatment, ensuring the reliability of the used equipment and confidence that all the patients have treated adequate. Where some parameter is above the tolerance is it possible to do proper corrections measures immediately. This QA protocols give assurance that specific objectives being successfully met

  9. Dose rate considerations in brachytherapy: biological equivalence of LDR and HDR

    International Nuclear Information System (INIS)

    Orton, C.G.

    1994-01-01

    The linear-quadratic model for cell survival and bioeffect doses is discussed and equations for low dose rate (LDR), high dose rate (HDR) and intermediate situations are presented. The model, when used to define LDR and single fractions of HDR, shows, that these correspond to irradiations lasting longer than about 14 hours or shorter than about 0.7 hours, respectively. It is shown that, for HDR to be as safe and effective as LDR, the dose-rate effect of LDR has to be replaced by the fractionation-effect of HDR. This is necessary in order to take advantage of the differential repair characteristics between late-reacting normal tissue and tumor cells at low doses and low dose rates. Using the linear-quadratic model to simulate repair mathematically, it is shown that the number of fractions required is highly dependent upon what parameters are assumed for normal tissues and tumor, as well as whether or not there is any physical advantage gained by conversion from LDR to HDR. (author). 20 refs., 7 figs

  10. Highly efficient CRISPR/HDR-mediated knock-in for mouse embryonic stem cells and zygotes.

    Science.gov (United States)

    Wang, Bangmei; Li, Kunyu; Wang, Amy; Reiser, Michelle; Saunders, Thom; Lockey, Richard F; Wang, Jia-Wang

    2015-10-01

    The clustered regularly interspaced short palindromic repeat (CRISPR) gene editing technique, based on the non-homologous end-joining (NHEJ) repair pathway, has been used to generate gene knock-outs with variable sizes of small insertion/deletions with high efficiency. More precise genome editing, either the insertion or deletion of a desired fragment, can be done by combining the homology-directed-repair (HDR) pathway with CRISPR cleavage. However, HDR-mediated gene knock-in experiments are typically inefficient, and there have been no reports of successful gene knock-in with DNA fragments larger than 4 kb. Here, we describe the targeted insertion of large DNA fragments (7.4 and 5.8 kb) into the genomes of mouse embryonic stem (ES) cells and zygotes, respectively, using the CRISPR/HDR technique without NHEJ inhibitors. Our data show that CRISPR/HDR without NHEJ inhibitors can result in highly efficient gene knock-in, equivalent to CRISPR/HDR with NHEJ inhibitors. Although NHEJ is the dominant repair pathway associated with CRISPR-mediated double-strand breaks (DSBs), and biallelic gene knock-ins are common, NHEJ and biallelic gene knock-ins were not detected. Our results demonstrate that efficient targeted insertion of large DNA fragments without NHEJ inhibitors is possible, a result that should stimulate interest in understanding the mechanisms of high efficiency CRISPR targeting in general.

  11. 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.

  12. Adaptive Motion Compensation in Radiotherapy

    CERN Document Server

    Murphy, Martin J

    2011-01-01

    External-beam radiotherapy has long been challenged by the simple fact that patients can (and do) move during the delivery of radiation. Recent advances in imaging and beam delivery technologies have made the solution--adapting delivery to natural movement--a practical reality. Adaptive Motion Compensation in Radiotherapy provides the first detailed treatment of online interventional techniques for motion compensation radiotherapy. This authoritative book discusses: Each of the contributing elements of a motion-adaptive system, including target detection and tracking, beam adaptation, and pati

  13. Development of targeted radiotherapy systems

    International Nuclear Information System (INIS)

    Ferro, Guillermina; Villarreal, Jose E.; Garcia, Laura; Tendilla, Jose I.; Paredes, Lydia; Murphy, Consuelo A.; Pedraza, Martha

    2001-01-01

    Conventional or external beam radiotherapy, has been a viable alternative for cancer treatment. Although this technique is effective, its use is limited if the patient has multiple malignant lesions (metastases). An alternative approach is based on the design of radiopharmaceuticals that, to be administered in the patient, are directed specifically toward the target cell producing a selective radiation delivery. This treatment is known as targeted radiotherapy. We have summarized and discussed some results related to our investigations on the development of targeted radiotherapy systems, including aspects of internal dosimetry

  14. Towards real-time 3D ultrasound planning and personalized 3D printing for breast HDR brachytherapy treatment

    International Nuclear Information System (INIS)

    Poulin, Eric; Gardi, Lori; Fenster, Aaron; Pouliot, Jean; Beaulieu, Luc

    2015-01-01

    Two different end-to-end procedures were tested for real-time planning in breast HDR brachytherapy treatment. Both methods are using a 3D ultrasound (3DUS) system and a freehand catheter optimization algorithm. They were found fast and efficient. We demonstrated a proof-of-concept approach for personalized real-time guidance and planning to breast HDR brachytherapy treatments

  15. Four R's of radiotherapy

    International Nuclear Information System (INIS)

    Withers, H.R.

    1975-01-01

    Radiotherapy given as multiple doses can be effective in sterilizing cancers, but the processes whereby the neoplasm is eradicated and the normal tissues are preserved are not fully understood. The differential between normal tissue and tumor response is enhanced by dose fractionation, single doses resulting in severe normal tissue injury when the dose is sufficient to control a proportion of treated tumors. Data are reviewed from radiobiological studies on laboratory animals and cultured cells that have thrown some light on four of the phenomena that influence the outcome of fractionated-dose radiotherapy, one or more of which may account for the relative sparing of normal tissues. These are repair of sublethal injury in normal and neoplastic cells, reoxygenation of the tumor, redistribution through the division cycle, and regeneration of surviving normal and malignant cells between dose fractions. These have been called the four R's of fractionated radiotherapy. Other factors are involved in the outcome of multifraction radiotherapy, including maintenance of the architectural integrity of the normal tissues, the volume of tissue irradi []ted, the tumor bed, and the immunocompetence of the host. (90 references) (CH)

  16. Interstitial radiotherapy

    International Nuclear Information System (INIS)

    Scardino, P.T.; Bretas, F.

    1987-01-01

    The authors now have 20 years of experience with modern techniques of brachytherapy. The large number of patients treated in medical centers around the world and the widespread use of this type of radiotherapy have provided us with substantial information about the indications and contraindications, advantages and disadvantages, pitfalls and complications, as well as the results of these techniques. Although the focus of this review is the experience at Baylor using the combined technique of gold seed implantation plus external beam irradiation, the alternative forms of brachytherapy will be described and compared. The authors' intention is to provide the busy clinician with a succinct and informative review indicating the status of modern interstitial radiotherapy and describing day-to-day approach and results

  17. 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.

  18. Multiobjective anatomy-based dose optimization for HDR-brachytherapy with constraint free deterministic algorithms

    International Nuclear Information System (INIS)

    Milickovic, N.; Lahanas, M.; Papagiannopoulou, M.; Zamboglou, N.; Baltas, D.

    2002-01-01

    In high dose rate (HDR) brachytherapy, conventional dose optimization algorithms consider multiple objectives in the form of an aggregate function that transforms the multiobjective problem into a single-objective problem. As a result, there is a loss of information on the available alternative possible solutions. This method assumes that the treatment planner exactly understands the correlation between competing objectives and knows the physical constraints. This knowledge is provided by the Pareto trade-off set obtained by single-objective optimization algorithms with a repeated optimization with different importance vectors. A mapping technique avoids non-feasible solutions with negative dwell weights and allows the use of constraint free gradient-based deterministic algorithms. We compare various such algorithms and methods which could improve their performance. This finally allows us to generate a large number of solutions in a few minutes. We use objectives expressed in terms of dose variances obtained from a few hundred sampling points in the planning target volume (PTV) and in organs at risk (OAR). We compare two- to four-dimensional Pareto fronts obtained with the deterministic algorithms and with a fast-simulated annealing algorithm. For PTV-based objectives, due to the convex objective functions, the obtained solutions are global optimal. If OARs are included, then the solutions found are also global optimal, although local minima may be present as suggested. (author)

  19. Large scale fire experiments in the HDR containment as a basis for fire code development

    International Nuclear Information System (INIS)

    Hosser, D.; Dobbernack, R.

    1993-01-01

    Between 1984 and 1991 7 different series of large scale fire experiments and related numerical and theoretical investigations have been performed in the containment of a high pressure reactor in Germany (known as HDR plant). The experimental part included: gas burner tests for checking the containment behaviour; naturally ventilated fires with wood cribs; naturally and forced ventilated oil pool fires; naturally and forced ventilated cable fires. Many results of the oil pool and cable fires can directly be applied to predict the impact of real fires at different locations in a containment on mechanical or structural components as well as on plant personnel. But the main advantage of the measurements and observations was to serve as a basis for fire code development and validation. Different types of fire codes have been used to predict in advance or evaluate afterwards the test results: zone models for single room and multiple room configurations; system codes for multiple room configurations; field models for complex single room configurations. Finally, there exist codes of varying degree of specialization which have proven their power and sufficient exactness to predict fire effects as a basis for optimum fire protection design. (author)

  20. Palliative Radiotherapy

    International Nuclear Information System (INIS)

    Salinas, J.

    2003-01-01

    Palliative care does not attempt to prolong survival but to the achieve the highest quality of life both for the patient and their family covering their physical, psychological, social and spiritual needs. Radiotherapy (RT), one of the most important therapeutic modalities, has a great significance in palliative medicine for cancer since it attempts to reduce as much as possible the acute reaction associated with the treatment for the patient. (Author)

  1. HDR imaging and color constancy: two sides of the same coin?

    Science.gov (United States)

    McCann, John J.

    2011-01-01

    At first, we think that High Dynamic Range (HDR) imaging is a technique for improved recordings of scene radiances. Many of us think that human color constancy is a variation of a camera's automatic white balance algorithm. However, on closer inspection, glare limits the range of light we can detect in cameras and on retinas. All scene regions below middle gray are influenced, more or less, by the glare from the bright scene segments. Instead of accurate radiance reproduction, HDR imaging works well because it preserves the details in the scene's spatial contrast. Similarly, on closer inspection, human color constancy depends on spatial comparisons that synthesize appearances from all the scene segments. Can spatial image processing play similar principle roles in both HDR imaging and color constancy?

  2. 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.

  3. Acceptance testing and commissioning of a new model HDR afterloader

    International Nuclear Information System (INIS)

    McDermott, Patrick N.; Somnay, Archana R.; Alecu, Rodica

    1996-01-01

    We have recently performed acceptance testing procedures and have commissioned a new model HDR afterloader, the Varian VariSource with ''Intelligent Drive.'' Our site was one of the first installations worldwide. It is our intent to describe our tests and the results of the tests particularly as they may differ from other afterloaders. The Ir-192 source is unique among afterloaders marketed in the US in that it is very slender (OD of source wire is 0.59 mm) and relatively long (two 0.5 cm sources for a total active length of 1.0 cm). A check of source homogeneity by autoradiograph as urged by the US Nuclear Regulatory Commission demonstrates no detectable source inhomogeneity. Reentrant well ionization chambers are calibrated in the US with a 3.5 mm long source at Accredited Dosimetry Calibration Laboratories. Therefore calibration needs to be considered with some care. Calibration of the first delivered source with a well ionization chamber indicated agreement with the manufacturer's stated activity to within 0.5%. Source positioning is checked with a device called a 'cam scale'. Tests have been carried out on this system and it has been found to accurately indicate source position to within ±0.5 mm. Timer accuracy has been found to be better than 0.1% for dwell times of several hundred seconds. The intelligent drive system and the small source diameter allow the source wire to negotiate paths with small radius of curvature. A series of tests have been made in which the source is forced to negotiate 'U' turns of decreasing radius of curvature. A 4.7 F, 100 cm long catheter was used for these tests and the 'U' turn was positioned at approximately 90 cm. Under these conditions, the VariSource was consistently able to traverse a 1.25 cm radius of curvature, which is better than the manufacturer's stated limit of 1.5 cm

  4. Quality assurance of HDR prostate plans: program implementation at a community hospital.

    Science.gov (United States)

    Rush, Jennifer B; Thomas, Michael D

    2005-01-01

    Adenocarcinoma of the prostate is currently the most commonly diagnosed cancer in men in the United States, and the second leading cause of cancer mortality. The utilization of radiation therapy is regarded as the definitive local therapy of choice for intermediate- and high-risk disease, in which there is increased risk for extracapsular extension, seminal vesicle invasion, or regional node involvement. High-dose-rate (HDR) brachytherapy is a logical treatment modality to deliver the boost dose to an external beam radiation therapy (EBRT) treatment to increase local control rates. From a treatment perspective, the utilization of a complicated treatment delivery system, the compressed time frame in which the procedure is performed, and the small number of large dose fractions make the implementation of a comprehensive quality assurance (QA) program imperative. One aspect of this program is the QA of the HDR treatment plan. Review of regulatory and medical physics professional publications shows that substantial general guidance is available. We provide some insight to the implementation of an HDR prostate plan program at a community hospital. One aspect addressed is the utilization of the low-dose-rate (LDR) planning system and the use of existing ultrasound image sets to familiarize the radiation therapy team with respect to acceptable HDR implant geometries. Additionally, the use of the LDR treatment planning system provided a means to prospectively determine the relationship between the treated isodose volume and the product of activity and time for the department's planning protocol prior to the first HDR implant. For the first 12 HDR prostate implants, the root-mean-square (RMS) deviation was 3.05% between the predicted product of activity and time vs. the actual plan values. Retrospective re-evaluation of the actual implant data reduced the RMS deviation to 2.36%.

  5. Quality assurance of HDR prostate plans: Program implementation at a community hospital

    International Nuclear Information System (INIS)

    Rush, Jennifer B.; Thomas, Michael D.

    2005-01-01

    Adenocarcinoma of the prostate is currently the most commonly diagnosed cancer in men in the United States, and the second leading cause of cancer mortality. The utilization of radiation therapy is regarded as the definitive local therapy of choice for intermediate- and high-risk disease, in which there is increased risk for extracapsular extension, seminal vesicle invasion, or regional node involvement. High-dose-rate (HDR) brachytherapy is a logical treatment modality to deliver the boost dose to an external beam radiation therapy (EBRT) treatment to increase local control rates. From a treatment perspective, the utilization of a complicated treatment delivery system, the compressed time frame in which the procedure is performed, and the small number of large dose fractions make the implementation of a comprehensive quality assurance (QA) program imperative. One aspect of this program is the QA of the HDR treatment plan. Review of regulatory and medical physics professional publications shows that substantial general guidance is available. We provide some insight to the implementation of an HDR prostate plan program at a community hospital. One aspect addressed is the utilization of the low-dose-rate (LDR) planning system and the use of existing ultrasound image sets to familiarize the radiation therapy team with respect to acceptable HDR implant geometries. Additionally, the use of the LDR treatment planning system provided a means to prospectively determine the relationship between the treated isodose volume and the product of activity and time for the department's planning protocol prior to the first HDR implant. For the first 12 HDR prostate implants, the root-mean-square (RMS) deviation was 3.05% between the predicted product of activity and time vs. the actual plan values. Retrospective re-evaluation of the actual implant data reduced the RMS deviation to 2.36%

  6. Neoadjuvant androgen deprivation and long-term results for patients with intermediate- and high-risk prostate cancer treated with high-dose rate brachytherapy and external beam radiotherapy

    International Nuclear Information System (INIS)

    Pellizzon, Antonio Cassio Assis; Fogaroli, Ricardo Cesar; Silva, Maria Leticia Gobo; Castro, Douglas Guedes; Maia, Maria Conte

    2010-01-01

    Purpose: to evaluate the influence of neoadjuvant androgen deprivation (NAAD) and report the long term biochemical control rates according to the Phoenix Consensus Conference, and prognostic factors of intermediate- (IR) and high-risk (HR) prostate cancer treated with external beam radiotherapy and high-dose-rate brachytherapy (HDR-BT). Methods and materials: between March, 1997 and June, 2005, 184 patients considered IR or HR were treated with localized radiotherapy and HDR-BT at the Department of Radiation Oncology, Hospital A.C. Camargo, Sao Paulo, Brazil. Patient's age, Gleason score, clinical stage, initial PSA value, risk group for biochemical failure, presence of NAAD, doses of radiotherapy and HDR-BT were evaluated. Results: median age and follow-up were 70 years old (range, 47-83) and 74.5 months (range, 24-123 months), respectively. Patients considered IR were 91 (49.4%) and HR 93 (50.6%). Ninety-nine (53.8%) patients had no NAAD. The overall survival at 5 years was 93.6%. The 5-year actuarial biochemical control rates for all patients, IR and HR were 83.4%, 86.2% and 78.8%, respectively, p0.076. On univariate analysis the prognostic factors related to better biochemical control were Gleason score 45 Gy (p= 0.011) and HDR-BT dose > 20 Gy (p< 0.001). On multivariate analysis no statistical significant predictive factor related to biochemical control was found. Conclusions: the role of NAAD for IR and HR prostate cancer is still to be defined. HDR-BT combined to external radiotherapy is a successful form of treatment for these patients, with our results comparable to published data. (author)

  7. Time to PSA rise differentiates the PSA bounce after HDR and LDR brachytherapy of prostate cancer.

    Science.gov (United States)

    Burchardt, Wojciech; Skowronek, Janusz

    2018-02-01

    To investigate the differences in prostate-specific antigen (PSA) bounce (PB) after high-dose-rate (HDR-BT) or low-dose-rate (LDR-BT) brachytherapy alone in prostate cancer patients. Ninety-four patients with localized prostate cancer (T1-T2cN0), age ranged 50-81 years, were treated with brachytherapy alone between 2008 and 2010. Patients were diagnosed with adenocarcinoma, Gleason score ≤ 7. The LDR-BT total dose was 144-145 Gy, in HDR-BT - 3 fractions of 10.5 or 15 Gy. The initial PSA level (iPSA) was assessed before treatment, then PSA was rated every 3 months over the first 2 years, and every 6 months during the next 3 years. Median follow-up was 3.0 years. Mean iPSA was 7.8 ng/ml. In 58 cases, PSA decreased gradually without PB or biochemical failure (BF). In 24% of patients, PB was observed. In 23 cases (24%), PB was observed using 0.2 ng/ml definition; in 10 cases (11%), BF was diagnosed using nadir + 2 ng/ml definition. The HDR-BT and LDR-BT techniques were not associated with higher level of PB (26 vs. 22%, p = 0.497). Time to the first PSA rise finished with PB was significantly shorter after HDR-BT then after LDR-BT (median, 10.5 vs. 18.0 months) during follow-up. Predictors for PB were observed only after HDR-BT. Androgen deprivation therapy (ADT) and higher Gleason score decreased the risk of PB (HR = 0.11, p = 0.03; HR = 0.51, p = 0.01). The higher PSA nadir and longer time to PSA nadir increased the risk of PB (HR 3.46, p = 0.02; HR 1.04, p = 0.04). There was no predictors for PB after LDR-BT. HDR-BT and LDR-BT for low and intermediate risk prostate cancer had similar PB rate. The PB occurred earlier after HDR-BT than after LDR-BT. ADT and higher Gleason score decreased, and higher PSA nadir and longer time to PSA nadir increased the risk of PB after HDR-BT.

  8. Quality assurance in radiotherapy

    International Nuclear Information System (INIS)

    2003-03-01

    Good radiotherapy results and safety of treatment require the radiation to be optimally applied to a specified target area and the correct dose. According to international recommendations, the average uncertainty in therapeutic dose should not exceed 5%. The need for high precision in therapeutic dose requires quality assurance covering the entire radiotherapy process. Besides the physical and technical characteristics of the therapy equipment, quality assurance must include all radiotherapy equipment and procedures that are significant for the correct magnitude and precision of application of the therapeutic dose. The duties and responsibilities pertaining to various stages of treatment must also be precisely defined. These requirements may be best implemented through a quality system. The general requirements for supervision and quality assurance of medical radiation apparatus are prescribed in section 40 of the Radiation Act (592/1991, amendment 1142/1998) and in sections 18 and 32 of the Decree of the Ministry of Social Affairs and Health on the medical use of radiation (423/2000). Guide ST 2.2 imposes requirements on structural radiation shielding of radiotherapy equipment and the premises in which it is used, and on warning and safety arrangements. Guide ST 1.1 sets out the general safety principles for radiation practices and regulatory control procedure for the use of radiation. Guide ST 1.6 provides general requirements for operational measures in the use of radiation. This Guide sets out the duties of responsible parties (the party running a radiation practice) in respect of arranging and maintaining radiotherapy quality assurance. The principles set out in this Guide and Guide ST 6.3 may be applied to radionuclide therapy

  9. Conformation radiotherapy and conformal radiotherapy

    International Nuclear Information System (INIS)

    Morita, Kozo

    1999-01-01

    In order to coincide the high dose region to the target volume, the 'Conformation Radiotherapy Technique' using the multileaf collimator and the device for 'hollow-out technique' was developed by Prof. S. Takahashi in 1960. This technique can be classified a type of 2D-dynamic conformal RT techniques. By the clinical application of this technique, the late complications of the lens, the intestine and the urinary bladder after radiotherapy for the maxillary cancer and the cervical cancer decreased. Since 1980's the exact position and shape of the tumor and the surrounding normal tissues can be easily obtained by the tremendous development of the CT/MRI imaging technique. As a result, various kinds of new conformal techniques such as the 3D-CRT, the dose intensity modulation, the tomotherapy have been developed since the beginning of 1990'. Several 'dose escalation study with 2D-/3D conformal RT' is now under way to improve the treatment results. (author)

  10. SU-G-201-15: Nomogram as an Efficient Dosimetric Verification Tool in HDR Prostate Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Liang, J; Todor, D [Virginia Commonwealth University, Richmond, VA (United States)

    2016-06-15

    Purpose: Nomogram as a simple QA tool for HDR prostate brachytherapy treatment planning has been developed and validated clinically. Reproducibility including patient-to-patient and physician-to-physician variability was assessed. Methods: The study was performed on HDR prostate implants from physician A (n=34) and B (n=15) using different implant techniques and planning methodologies. A nomogram was implemented as an independent QA of computer-based treatment planning before plan execution. Normalized implant strength (total air kerma strength Sk*t in cGy cm{sup 2} divided by prescribed dose in cGy) was plotted as a function of PTV volume and total V100. A quadratic equation was used to fit the data with R{sup 2} denoting the model predictive power. Results: All plans showed good target coverage while OARs met the dose constraint guidelines. Vastly different implant and planning styles were reflected on conformity index (entire dose matrix V100/PTV volume, physician A implants: 1.27±0.14, physician B: 1.47±0.17) and PTV V150/PTV volume ratio (physician A: 0.34±0.09, physician B: 0.24±0.07). The quadratic model provided a better fit for the curved relationship between normalized implant strength and total V100 (or PTV volume) than a simple linear function. Unlike the normalized implant strength versus PTV volume nomogram which differed between physicians, a unique quadratic model based nomogram (Sk*t)/D=−0.0008V2+0.0542V+1.1185 (R{sup 2}=0.9977) described the dependence of normalized implant strength on total V100 over all the patients from both physicians despite two different implant and planning philosophies. Normalized implant strength - total V100 model also generated less deviant points distorting the smoothed ones with a significantly higher correlation. Conclusion: A simple and universal, excel-based nomogram was created as an independent calculation tool for HDR prostate brachytherapy. Unlike similar attempts, our nomogram is insensitive to implant

  11. Why Radiotherapy Works. Chapter 6

    International Nuclear Information System (INIS)

    Tashiro, S.; Nishibuchi, I.; Wondergem, J.

    2017-01-01

    The history of radiotherapy began in 1895, when Röntgen discovered X rays, and in the following year, radiation was used for medical treatment. In the early days, the development of radiotherapy was based extensively on empiricism. Radiotherapists worked closely with radiation biologists in attempting to describe and understand the phenomena produced by ionizing radiation in the clinic and in biological systems. During the ensuing 120 years, radiotherapy has been improved significantly and, in addition to radiation biology, medical physics has played an important role in the design and development of equipment, quality assurance and dosimetry. Over recent decades, advances have been made in the field of molecular biology. Currently available techniques enable us to elucidate the molecular mechanisms of cellular response to ionizing irradiation, and it is anticipated that the role and contributions of radiation biology in radiotherapy will remain relevant. This chapter describes the clinically important biological points, including knowledge from current molecular biology.

  12. Management of a HDR brachytherapy system in the Hospital Juarez of Mexico; Gestion de un sistema de braquiterapia HDR een el Hospital Juarez de Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Serrano F, A.G.; Ramirez R, G.; Gil G, R. [Hospital Juarez de Mexico, Av. l.P.N. 5160, Col. Magdalena de las Salinas, 07760 Mexico D.F. (Mexico); Azorin N, J. [UAM-I, 09340 Mexico D.F. (Mexico); Rivera M, T. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Unidad Legaria del IPN, Av. Legaria 694, Col. Irrigacion, 11500 Mexico D.F. (Mexico)

    2007-07-01

    Full text: In the Hospital Juarez of Mexico, it is carried out a project to implement a Brachytherapy system with high dose rate (HDR) through a Management quality program. In our work center this treatment modality in patients with cervicouterine cancer is used (CaCu), and constantly it is necessary to carry out improvements in the procedures, with the purpose of optimizing them and in consequence to complete the principles of the Radiological Protection, guaranteeing this way, an attention with the quality and safety, such that allow to diminish the risks to the patients and to assure that the received dose in critical organs it finds inside the permitted therapeutic limits, without commit the radiosensitive response of healthy organs. In this work an analysis of the implementation of this system is presented, detailing the procedures so much in the technological infrastructure like human and indicating the necessary technical and operative requirements to reach an adequate practice in HDR brachytherapy. (Author)

  13. 3D dosimetry in HDR brachytherapy resonance imaging nuclear magnetic (b= 0.2 t) using a base acrylic gel (MAGIC)

    International Nuclear Information System (INIS)

    Batista Hernandez, Guillermo; Velez, Graciela R.; Schurrer, Clemar

    2009-01-01

    Dosimetry gels using magnetic resonance imaging (MRI) has been extended in recent literature. Our study presents the preparation, calibration IRM of acrylic gel (MAGIC) and its application in measuring dose in a 3D distribution HDR Brachytherapy with 192Ir source. The first gels used were the type Fricke gels based on the relationship of dose and time T1 relaxation. In 2001, Fong presented a new normoxic gel known as MAGIC whose main components are Methacrylic Acid (polymerizing), and Hydroquinone (inhibitor of self-curing) based on the relationship of dose and T2 relaxation time. Subsequent studies make changes in the concentrations component of the MAGIC (Methacrylic Acid and Hydroquinone in particular) to observe the behavior of the sensitivity of the gel with respect to its components and beam magnetic resonance equipment using magnetic fields higher to 0.5 T. This is done with equipment available to the staff of a Radiotherapy clinic setting. MAGIC gel is prepared according to composition by Crescenti (6% methacrylic acid), is calibrated with a 60Co unit TERADI INVAP 8002c (Argentina). Was raised shooting in a Siemens MRI scanner of 0.2 T Magnetom Concerto irradiated with a team of Brachytherapy High Dose Rate (HDR) Micro selectron Nucletron's V2 HDR for comparison with dose distributions provided by the planning system from Nucletron PLATO Sunrise. Was obtained a calibration curve for doses ranging from 0 to 8.0 Gy and a field strength 0.2 T magnetic We compared the sensitivity obtained in our calibration (Slope of the calibration curve) with those presented in the literature. Two phantoms were prepared for measurement in brachytherapy: a PMMA and a PVC. It was noted that MAGIC gel reacts chemically with PMMA and cured prior to irradiation. The phantom of PVC (no reactions) were irradiated with Micro selectron equipment and measured the dose distribution in 3D MRI. Were measured doses at the points specified by the Planning System and PLATO Sunrise compared

  14. Emergency rescue in accidents with HDR afterloading units

    International Nuclear Information System (INIS)

    Kaulich, T.W.; Nuesslin, F.; Becker, G.; Lamprecht, U.; Bamberg, M.

    1999-01-01

    Problem: HDR brachyradiotherapy has minimized the exposure to radiation of the personnel working in this field. Nonetheless there are periodically reported troubles with afterloading units concerning the retraction of sources that require immediate action for the limitation of possible damage. Legal Principles according to the German Regulation Concerning Protection against Radiation (Strahlenschutzverordnung=StrlSchV): If in afterloading brachyradiotherapy the radiation source remains extended through malfunction we deal with an emergency according to the StrlSchV. The rescue personnel should be chosen in accordance with Paragraph 50 StrlSchV. Organization of the Rescue of the Patient: The quickest possible rescue of a patient in an emergency demands an unequivocal definition of responsibilities. Our recommendations in this instance: The physicist is responsible for the organization of the emergency rescue. The radiation oncologist in charge informs himself about the necessary emergency measures before starting the treatment and carries out the emergency rescue. If the physicist diagnoses a failure in the retraction of the source he tries to remove the failure. If he doesn't succeed in retracting the source the radiation oncologist carries out the rescue of the patient. The organizational structure of the clinic allowing, the emergency physician should invariably be the physician who placed the applicator. In the emergency rescue the radiation oncologist should be protected by a lead barrier and use manipulators. Dose Assessment in Personnel and Patient: The radiation exposure of the rescue personnel is calculated from the photon-equivalence dose H x with the help of the dose-rate constant of 192 Ir. According to the same procedure there can be evaluated the local radiation exposure of the patient concerned. Conclusions: Generally speaking, all considerations regarding the topic of emergency rescue should always start out from a worst-case scenario. Of all the

  15. Quality assurance in radiotherapy of mammary cancer

    International Nuclear Information System (INIS)

    Mangold, C.A.

    2000-11-01

    The outcome of breast conserving treatment, in terms of local control, cosmetic outcome, and complication rate depends on the quality of surgery and on the adequacy of the irradiation treatment performed. In the radiotherapy department of Leuven and the AKH Vienna about 70 % of all breast cancer patients are treated with breast conserving surgery and external radiotherapy. About 20 % of the patients treated with external radiotherapy receive an additional boost with pulse dose rate (PDR) or high dose rate (HDR) brachytherapy using Ir-192 sources. An investigation is performed to assess the accuracy of both treatment techniques. Secondly, the feasibility of in vivo measurements is studied for these two treatment techniques. For investigating the accuracy of the brachytherapy treatment two phantoms are manufactured to mimic a breast, one for TLD measurements, and one for film dosimetry using radiochromic films. The TLD phantom allows to measure at 34 dose points in three planes including the basal dose points. The film phantom is designed in such a way that films can be positioned in a plane parallel and orthogonal to the needles. In vivo measurements are simulated on one of the phantoms and carried out on 21 patients. The accuracy of the external radiotherapy treatment is checked with the thorax part of a commercially available Alderson phantom. It allows to perform measurements with TLDs in three different planes and with diodes on the surface. Furthermore, all diode characteristics and correction factors necessary for the clinical application are investigated. For the brachytherapy treatment the dose distributions calculated with the TPS are in good agreement with both TLD and radiochromic film measurements (average deviations of point doses < ± 6 %). However, close to the interface tissue-air the dose is overestimated by the TPS since it neglects the finite size of a breast and hence the associated lack of backscatter (average deviations of point doses up to -13

  16. Radiotherapy and Brachytherapy : Proceedings of the NATO Advanced Study Institute on Physics of Modern Radiotherapy & Brachytherapy

    CERN Document Server

    Lemoigne, Yves

    2009-01-01

    This volume collects a series of lectures presented at the tenth ESI School held at Archamps (FR) in November 2007 and dedicated to radiotherapy and brachytherapy. The lectures focus on the multiple facets of radiotherapy in general, including external radiotherapy (often called teletherapy) as well as internal radiotherapy (called brachytherapy). Radiotherapy strategy and dose management as well as the decisive role of digital imaging in the associated clinical practice are developed in several articles. Grouped under the discipline of Conformal Radiotherapy (CRT), numerous modern techniques, from Multi-Leaf Collimators (MLC) to Intensity Modulated RadioTherapy (IMRT), are explained in detail. The importance of treatment planning based upon patient data from digital imaging (Computed Tomography) is also underlined. Finally, despite the quasi- totality of patients being presently treated with gamma and X-rays, novel powerful tools are emerging using proton and light ions (like carbon ions) beams, bound to bec...

  17. Determinación de la distribución de dosis en tratamientos de cáncer de mama con fuentes de 192 Ir HDR / Determination of doses distributions on breast cancer treatments with 192 Ir HDR sources

    OpenAIRE

    Beltrán Gómez, Cristian Camilo

    2010-01-01

    La Braquiterapia de alta tasa de dosis HDR es una moderna técnica de tratamiento que ha venido teniendo un rápido crecimiento en su uso clínico, reemplazando a la braquiterapia de baja tasa de dosis LDR. La braquiterapia HDR se caracteriza por utilizar fuentes radiactivas con tasas de dosis mayores a 12 Gy/h, por tanto con propósitos de protección radiológica debe ser realizada con equipos de carga remota, es común en los tratamientos de braquiterapia HDR depositar altas dosis por fracción, c...

  18. 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.

  19. Determination of the dose of traffic in HDR brachytherapy with ALANINE/R PE technique

    International Nuclear Information System (INIS)

    Guzman Calcina, C. S.; Chen, F.; Almeida, A. de; Baffa, O.

    2001-01-01

    It determines, experimentally, the dose of traffic in brachytherapy for High Dose Rate (HDR), using for the first-time the Electronic Paramagnetic Resonance (EPR) technique with alanine detectors. The value obtained is the published next to obtained using lithium fluoride thermoluminescent dosimeters [es

  20. 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.

  1. 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...

  2. 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

    In this paper, we will demonstrate a comparison between measured colorimetric images, and simulated images from a physics based rendering engine. The colorimetric images are high dynamic range (HDR) and taken with a luminance and colour camera mounted on a goniometer. For the comparison, we have ...

  3. Quality control and performance evaluation of microselectron HDR machine over 30 months

    International Nuclear Information System (INIS)

    Balasubramanian, N.; Annex, E.H.; Sunderam, N.; Patel, N.P.; Kaushal, V.

    2008-01-01

    To assess the performance evaluation of Microselectron HDR machine the standard quality control and quality assurance checks were carried out after each loading of new 192 Ir brachytherapy source In the machine. Total 9 loadings were done over a period of 30 months

  4. Implementation of the technique of partial irradiation accelerated the breast with high doses (HDR) brachytherapy

    International Nuclear Information System (INIS)

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

    2013-01-01

    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)

  5. HDR brachytherapy in carcinoma of cervix: initial experience at AWARE hospitals

    International Nuclear Information System (INIS)

    Rajendran, M.; Reddy, K.D.; Reddy, R.M.; Reddy, J.M.; Reddy, B.V.N.; Kiran Kumar; Gopi, S.; Dharaniraj; Janardhanan

    2002-01-01

    High dose rate (HDR) brachytherapy is well established in the management of gynaecological malignancies. A report on the initial results of one and half year experience with a consistent dose/fractionation schedule and procedure of planning with delivery of treatment schedule is presented

  6. 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

  7. Optimum radiotherapy schedule for uterine cervical cancer based-on the detailed information of dose fractionation and radiotherapy technique

    International Nuclear Information System (INIS)

    Cho, Jae Ho; Kim, Hyun Chang; Suh, Chang Ok

    2005-01-01

    The best dose-fractionation regimen of the definitive radiotherapy for cervix cancer remains to be clearly determined. It seems to be partially attributed to the complexity of the affecting factors and the lack of detailed information on external and intra-cavitary fractionation. To find optimal practice guidelines, our experiences of the combination of external beam radiotherapy (EBRT) and high-dose-rate intracavitary brachytherapy (HDR-ICBT) were reviewed with detailed information of the various treatment parameters obtained from a large cohort of women treated homogeneously at a single institute. The subjects were 743 cervical cancer patients (Stage IB 198, IIA 77, IIB 364, IIIA 7, IIIB 89 and IVA 8) treated by radiotherapy alone, between 1990 and 1996. A total external beam radiotherapy (EBRT) dose of 23.4 ∼ 59.4 Gy (Median 45.0) was delivered to the whole pelvis. High-dose-rate intracavitary brachytherapy (HDR-ICBT) was also performed using various fractionation schemes. A Midline block (MLB) was initiated after the delivery of 14.4∼ 43.2 Gy (Median 36.0) of EBRT in 495 patients, while in the other 248 patients EBRT could not be used due to slow tumor regression or the huge initial bulk of tumor. The point A, actual bladder and rectal doses were individually assessed in all patients. The biologically effective dose (BED) to the tumor (α / β = 10) and late-responding tissues (α /β = 3) for both EBRT and HDR-ICBT were calculated. The total BED values to point A, the actual bladder and rectal reference points were the summation of the EBRT and HDR-ICBT. In addition to all the details on dose-fractionation, the other factors (i.e. the overall treatment time, physicians preference) that can affect the schedule of the definitive radiotherapy were also thoroughly analyzed. The association between MD-BED Gy 3 and the risk of complication was assessed using serial multiple logistic regressions models. The associations between R-BED Gy 3 and rectal complications

  8. Bone Health and Pelvic Radiotherapy.

    Science.gov (United States)

    Higham, C E; Faithfull, S

    2015-11-01

    Survivors who have received pelvic radiotherapy make up many of the long-term cancer population, with therapies for gynaecological, bowel, bladder and prostate malignancies. Individuals who receive radiotherapy to the pelvis as part of their cancer treatment are at risk of insufficiency fractures. Symptoms of insufficiency fractures include pelvic and back pain and immobility, which can affect substantially quality of life. This constellation of symptoms can occur within 2 months of radiotherapy up to 63 months post-treatment, with a median incidence of 6-20 months. As a condition it is under reported and evidence is poor as to the contributing risk factors, causation and best management to improve the patient's bone health and mobility. As radiotherapy advances, chronic symptoms, such as insufficiency fractures, as a consequence of treatment need to be better understood and reviewed. This overview explores the current evidence for the effect of radiotherapy on bone health and insufficiency fractures and identifies what we know and where gaps in our knowledge lie. The overview concludes with the need to take seriously complaints of pelvic pain from patients after pelvic radiotherapy and to investigate and manage these symptoms more effectively. There is a clear need for definitive research in this field to provide the evidence-based guidance much needed in practice. Copyright © 2015 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  9. Radiotherapy in bladder cancer

    International Nuclear Information System (INIS)

    Rozan, R.

    1992-01-01

    In 1992, the problem of the vesical radiotherapy is not resolved. The author presents the situation and the different techniques of radiotherapy in bladder cancers: external radiotherapy, only and associated with surgery, interstitial curietherapy and non-classical techniques as per operative radiotherapy, neutron therapy and concurrent radiotherapy with chemotherapy. In order to compare their efficiency, the five-year survival are given in all cases.(10 tabs)

  10. Needle displacement during HDR brachytherapy in the treatment of prostate cancer

    International Nuclear Information System (INIS)

    Damore, Steven J.; Syed, A.M. Nisar; Puthawala, Ajmel A.; Sharma, Anil

    2000-01-01

    Purpose: We used clinical patient data to examine implant displacement between high dose rate (HDR) brachytherapy fractions for prostate cancer to determine its impact on treatment delivery. Materials and Methods: We analyzed the verification films taken prior to each fraction for 96 consecutive patients treated with HDR brachytherapy boosts as part of their radiation therapy for definitive treatment of organ-confined prostate cancer at our institution. Patients were treated with 18-24 Gy in 4 fractions of HDR delivered in 40 hours followed by 36-39.6 Gy external beam radiation to the prostate. We determined the mean and maximum displacement distances of marker seeds placed in the prostate and of the implanted needles between HDR fractions. Results: Mean and maximum displacement distances between fractions were documented up to 7.6 mm and 28.5 mm, respectively, for the implant needles and 3.6 mm and 11.4 mm, respectively, for the gold marker seeds. All displacement of implant needles occurred in the caudal direction. At least 1 cm caudal displacement of needles occurred prior to 15.5% all fractions. Manual adjustment of needles was required prior to 15% of fractions, and adjustment of the CLP only was required in 24%. Most of the displacement for both the marker seeds and needles occurred between the first and second fractions. Conclusions: There is significant caudal displacement of interstitial implant needles between HDR fractions in our prostate cancer patients. Obtaining verification films and making adjustments in the treatment volume prior to each fraction is necessary to avoid significant inaccuracies in treatment delivery

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

    International Nuclear Information System (INIS)

    Li, J S; Ma, C

    2014-01-01

    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

  12. Perioperative high dose rate (HDR brachytherapy in unresectable locally advanced pancreatic tumors

    Directory of Open Access Journals (Sweden)

    Brygida Białas

    2011-07-01

    Full Text Available Purpose: The aim of the study was to present an original technique of catheter implantation for perioperative HDR-Ir192 brachytherapy in patients after palliative operations of unresectable locally advanced pancreatic tumors and to estimate the influence of perioperative HDR-Ir192 brachytherapy on pain relief in terminal pancreatic cancer patients. Material and methods: Eight patients with pancreatic tumors located in the head of pancreas underwent palliative operations with the use of HDR-Ir192 brachytherapy. All patients qualified for surgery reported pain of high intensity and had received narcotic painkillers prior to operation. During the last phase of the surgery, the Nucletron® catheters were implanted in patients to prepare them for later perioperative brachytherapy. Since the 6th day after surgery HDR brachytherapy was performed. Before each brachytherapy fraction the location of implants were checked using fluoroscopy. A fractional dose was 5 Gy and a total dose was 20 Gy in the area of radiation. A comparative study of two groups of patients (with and without brachytherapy with stage III pancreatic cancer according to the TNM scale was taken in consideration. Results and Conclusions: The authors claim that the modification of catheter implantation using specially designed cannula, facilitates the process of inserting the catheter into the tumor, shortens the time needed for the procedure, and reduces the risk of complications. Mean survival time was 5.7 months. In the group of performed brachytherapy, the mean survival time was 6.7 months, while in the group of no brachytherapy performed – 4.4 months. In the group of brachytherapy, only one patient increased the dose of painkillers in the last month of his life. Remaining patients took constant doses of medicines. Perioperative HDR-Ir192 brachytherapy could be considered as a practical application of adjuvant therapy for pain relief in patients with an advanced pancreatic cancer.

  13. Updated results of high-dose rate brachytherapy and external beam radiotherapy for locally and locally advanced prostate cancer using the RTOG-ASTRO phoenix definition

    Directory of Open Access Journals (Sweden)

    Antonio C. Pellizzon

    2008-06-01

    Full Text Available PURPOSE: To evaluate the prognostic factors for patients with local or locally advanced prostate cancer treated with external beam radiotherapy (RT and high dose rate brachytherapy (HDR according to the RTOG-ASTRO Phoenix Consensus Conference. MATERIALS AND METHODS: The charts of 209 patients treated between 1997 and 2005 with localized RT and HDR as a boost at the Department of Radiation Oncology, AC Camargo Hospital, Sao Paulo, Brazil were reviewed. Clinical and treatment parameters i.e.: patient's age, Gleason score, clinical stage, initial PSA (iPSA, risk group (RG for biochemical failure, doses of RT and HDR were evaluated. Median age and median follow-up time were 68 and 5.3 years, respectively. Median RT and HDR doses were 45 Gy and 20 Gy. RESULTS: Disease specific survival (DSS at 3.3 year was 94.2%. Regarding RG, for the LR (low risk, IR (intermediate risk and HR (high risk, the DSS rates at 3.3 years were 91.5%, 90.2% and 88.5%, respectively. On univariate analysis prognostic factors related to DSS were RG (p = 0.040, Gleason score ≤ 6 ng/mL (p = 0.002, total dose of HDR ≥ 20 Gy (p < 0.001 On multivariate analysis the only statistical significant predictive factor for biochemical control (bNED was the RG, p < 0.001 (CI - 1.147-3.561. CONCLUSIONS: Although the radiation dose administered to the prostate is an important factor related to bNED, this could not be established with statistical significance in this group of patients. To date , in our own experience, HDR associated to RT could be considered a successful approach in the treatment of prostate cancer.

  14. High-Dose-Rate Brachytherapy and External-Beam Radiotherapy for Hormone-Naïve Low- and Intermediate-Risk Prostate Cancer: A 7-Year Experience

    International Nuclear Information System (INIS)

    Aluwini, Shafak; Rooij, Peter H. van; Kirkels, Wim J.; Jansen, Peter P.; Praag, John O.; Bangma, Chris H.; Kolkman-Deurloo, Inger-Karine K.

    2012-01-01

    Purpose: To report clinical outcomes and early and late complications in 264 hormone-naïve patients with low- and intermediate-risk prostate cancer treated with high-dose-rate brachytherapy (HDR-BT) in combination with external-beam radiotherapy (EBRT). Methods and Materials: Between February 2000 and July 2007, 264 patients underwent HDR-BT in combination with EBRT as a treatment for their low- to intermediate-risk prostate cancer. The HDR-BT was performed using ultrasound-based implantation. The total HDR-BT dose was 18 Gy in 3 fractions within 24 h, with a 6-h minimum interval. The EBRT started 2 weeks after HDR-BT and was delivered in 25 fractions of 1.8 Gy to 45 Gy within 5 weeks. Results: After a mean follow-up of 74.5 months, 4 patients (1.5%) showed prostate-specific antigen progression according to the American Society for Radiation Oncology definition and 8 patients (3%) according to the Phoenix definition. A biopsy-proven local recurrence was registered in 1 patient (0.4%), and clinical progression (bone metastases) was documented in 2 patients (0.7%). Seven-year actuarial freedom from biochemical failure was 97%, and 7-year disease-specific survival and overall survival were 100% and 91%, respectively. Toxicities were comparable to other series. Conclusions: Treatment with interstitial HDR-BT plus EBRT shows a low incidence of late complications and a favorable oncologic outcome after 7 years follow-up.

  15. The Role of Radiotherapy in the Treatment of Extrahepatic Bile Duct Carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Hyun Soo; Kim, Gwi Eon; Lee, Hyung Sik; Suh, Chang Ok; Loh, John Ku; Lee, Jong Tae [Yonsei National University College of Medicine, Seoul (Korea, Republic of)

    1991-12-15

    Twenty-seven patients with unresectable extrahepatic bile duct carcinoma (n=21) or with microscopic evidence of tumor rest after aggressive surgery for extrahepatic bile duct carcinoma(n=6) between 1985 and 1990 were given radiotherapy consisting intentionally external radiotherapy and /or intraluminal therapy using Gamma-Med 12i (192-lr) high dose rate (HDR) remote control afterloading system following bile drainage procedures and Gianturco stent insertion. The objectives of this study has been to assess the feasibility and effects on survival of a combination of external radiotherapy and brachytherapy with which we hope to achieve optimal loco-regional control for patients with unresectable extrahepatic bile duct tumors. Sixteen patients were men and eleven were women, and the mean age was 58 years (34-70 ). 10MV X-ray was used for radiation therapy, with the total dose ranging from 45 Gy to 55 Gy, and intraluminal brachytherapy performed after external radiotherapy, with the dose of total 15 Gy. The minimum follow up was 12 months. Failure were predominantly local-regional, without distant failure. Median survival was 10 months; 2-year actuarial survival rates was 21%. Median survival for common hepatic duct(CHD) cancer was 9 months; for common bile duct (CBD) cancer, was 16 months. And median survival for incomplete surgery/external radiotherapy group and external/intraluminal radiotherapy group was 10 months; for external radiotherapy alone group, was 6 months. Use of chemotherapy and/or hyperthermia were not affected in survival. Therefore, our result is that the survival rates in the group of external/intraluminal radiotherapy were comparable with ones in the group of incomplete resection/external radiotherapy, and so we believe that the aggressive local and regional radiotherapy can improve the quality of life and the survival length.

  16. Rectal Bleeding After High-Dose-Rate Brachytherapy Combined With Hypofractionated External-Beam Radiotherapy for Localized Prostate Cancer: The Relationship Between Dose-Volume Histogram Parameters and the Occurrence Rate

    International Nuclear Information System (INIS)

    Okamoto, Masahiko; Ishikawa, Hitoshi; Ebara, Takeshi; Kato, Hiroyuki; Tamaki, Tomoaki; Akimoto, Tetsuo; Ito, Kazuto; Miyakubo, Mai; Yamamoto, Takumi; Suzuki, Kazuhiro; Takahashi, Takeo; Nakano, Takashi

    2012-01-01

    Purpose: To determine the predictive risk factors for Grade 2 or worse rectal bleeding after high-dose-rate brachytherapy (HDR-BT) combined with hypofractionated external-beam radiotherapy (EBRT) for prostate cancer using dose–volume histogram analysis. Methods and Materials: The records of 216 patients treated with HDR-BT combined with EBRT were analyzed. The treatment protocols for HDR-BT were 5 Gy × five times in 3 days or 7 Gy × three, 10.5 Gy × two, or 9 Gy × two in 2 days. The EBRT doses ranged from 45 to 51 Gy with a fractional dose of 3 Gy. Results: In 20 patients Grade 2 or worse rectal bleeding developed, and the cumulative incidence rate was 9% at 5 years. By converting the HDR-BT and EBRT radiation doses into biologic effective doses (BED), the BED 3 at rectal volumes of 5% and 10% in the patients who experienced bleeding were significantly higher than those in the remaining 196 patients. Univariate analysis showed that a higher rectal BED 3–5% and the use of fewer needles in brachytherapy were correlated with the incidence of bleeding, but BED 3–5% was found to be the only significant factor on multivariate analysis. Conclusions: The radiation dose delivered to small rectal lesions as 5% is important for predicting Grade 2 or worse rectal bleeding after HDR-BT combined with EBRT for prostate cancer.

  17. Comparison of three radiotherapy modalities on biochemical control and overall survival for the treatment of prostate cancer: A systematic review

    International Nuclear Information System (INIS)

    Pieters, Bradley R.; Back, Djuna Z. de; Koning, Caro C.E.; Zwinderman, Aeilko H.

    2009-01-01

    Background and Purpose: For the radiation treatment of prostate cancer high dose should be delivered for optimal biochemical control. Treatment can be given by dose-escalated external beam radiotherapy (EBRT) or external beam radiotherapy combined with a radioactive seed implantation (EBSeeds) or high-dose rate (HDR) brachytherapy (EBTI). Differences in outcome between the modalities were assessed by a systematic review. Materials and methods: A systematic search was performed resulting in 40 articles to be used. Data were extracted on biochemical control and overall survival at 3, 5, and 8 years and other time points mentioned in the articles. Also known prognostic parameters were noted. Comparison of the modalities was done by a Weibull survival analysis and estimation of Hazard Ratio's (HR) was done with 95% confidence intervals (95% CIs). Results: The HR for biochemical recurrence was 1.40 (95% CI 1.31-1.51) for EBRT relative to EBTI, and was 1.37 (95% CI 1.26-1.49) for EBSeeds relative to EBTI. The HR for overall survival was 1.50 (95% CI 1.29-1.73) for EBRT relative to EBTI, and was 2.33 (95% CI 2.04-2.66) for EBSeeds relative to EBTI. Conclusion: The combination of external beam radiotherapy and HDR brachytherapy results in a superior biochemical control and overall survival found in a systematic review on radiotherapy for prostate cancer.

  18. Stereotactic body radiotherapy for localized prostate cancer: disease control and quality of life at 6 years

    International Nuclear Information System (INIS)

    Katz, Alan J; Santoro, Michael; Diblasio, Fred; Ashley, Richard

    2013-01-01

    low and acceptable toxicity, outcomes consistent with those reported for from high dose rate brachytherapy (HDR BT). Provided that measures are taken to account for prostate motion, SBRT’s distinct advantages over HDR BT include its noninvasiveness and delivery to patients without anesthesia or hospitalization

  19. Results of different modes conformal radiotherapy in treatment of cervical cancer

    International Nuclear Information System (INIS)

    Baranovs'ka, L.M.; Yivankova, V.S.; Khrulenko, T.V.; Skomorokhova, T.V.; Gorelyina, G.L.

    2017-01-01

    Development of techniques for cytotoxic treatment applying different modes of conformal radiotherapy, brachytherapy and high-energy (high dose rate - HDR) is one of the promising areas of optimization and efficiency of conservative treatment of patients with regional forms of cervical cancer. At Radiation Oncology Department, National Cancer Institute, 89 patients with stage 2b-3b cervical cancer, aged 29 to 70, underwent examination and combined radiotherapy course. The patients were divided into 2 main groups (56 patients) depending on the mode of developed conformal radiation therapy, and a control group made up by 33 patients (classic, default conformal radiotherapy). Results. Along with external beam radiotherapy, the patients of Group 2 were provided with conformal radiotherapy carried out by means of the linear accelerator of electrons in the mode of enhanced multi fractionation of irradiation dose applied to the small pelvis area (tumor and lymph efflux channels) with the single tumor dose 1.3 Gy twice per day once 4-6 hours up to the total radiation dose of 45 Gy applied to the small pelvis lymph nodes. The patients of Group 1 and the ones of the control group underwent conformal radiotherapy in the mode of standard fractionation applied to the small pelvis area with the single tumor dose of 1.8 Gy up to the total radiation dose of 45 Gy. Conformal radiotherapy was carried out for the patients of Group 1 associated with chemoradiomodifiers (tegafur, cisplatin). At the stage 2 of combined radiotherapy course, all patients underwent HDR brachytherapy via Co60 source in the mode of the single tumor dose of 5 Gy at point A up to the total radiation dose of 35-40 Gy. Therefore, employing accelerated mode of multifractiation in conformal radiotherapy of patients with regional cervical cancer makes it possible to enhance canrcinocidal irradiation doses applied to a tumor, and an interval between radiotherapy fractions provides conditions for initiation of

  20. Combined radiotherapy and chemotherapy for head and neck cancer

    International Nuclear Information System (INIS)

    Inuyama, Yukio; Fujii, Masato; Tanaka, Juichi; Takaoka, Tetsuro; Hosoda, Hyonosuke; Kawaura, Mitsuhiro; Toji, Masao

    1988-01-01

    There are 4 modalities of combined radiotherapy and chemotherapy which include (1) concurrent radiotherapy and chemotherapy, (2) sequential use of radiotherapy and chemotherapy (pre-radiation chemotherapy), (3) pre-radiation chemotherapy followed by concurrent radiation and chemotherapy, and (4) alternating use of radiotherapy and chemotherapy based upon Looney's hypothesis. We studied concurrent use of radiotherapy and UFT by means of animal experimentation and clinical trials. The results obtained revealed that UFT was a most suitable agent together with 5-fluorouracil for concurrent application of radiotherapy and chemotherapy. Neo-adjuvant chemotherapy including pre-radiation chemotherapy was also studied in cases of maxillary sinus carcinoma and nasopharyngeal carcinoma. From the results, it seemed desirable to use cisplatin and bleomycin analogs sequentially in combined chemotherapy and radiotherapy. Neo-adjuvant chemotherapy should be studied successively to improve local tumor control rates and prevent distant metastases. For future perspectives, new trials of alternating radiotherapy and chemotherapy based upon Looney's hypothesis seem necessary. (author)

  1. Radiotherapy in Cancer Management

    International Nuclear Information System (INIS)

    Abdel-Wahab, M.

    2015-01-01

    Radiotherapy has been used for curative or palliative treatment of cancer, either alone or increasingly as part of a multimodality approach in conjunction with chemotherapy, immunotherapy or surgery. Radiation must be delivered in the safest and most effective way. The use of radiologic and nuclear medicine diagnostic techniques, e.g., the use of CT (Computerized Tomography) and PET/CT allow better detection and staging of diseases by displaying both morphological and functional abnormalities within the affected organs and are essential in the process of radiotherapy planning. Technical advances in radiotherapy have allowed better targeting of tumors, sparing of normal tissue and, in the case of radiosurgery, a decrease in the number of treatments. The IAEA Programme in Human Health aims to enhance the capabilities in Member States to address needs related to the treatment of diseases, including cancer, through the application of nuclear techniques. The Programme supports quality assurance in radiation medicine; DIRAC, the only radiation oncology-specific resource database world-wide; significant, innovative education and training programmes through telemedicine and e-learning accessible via the human health campus website. Technical expertise for country– and region–specific technical cooperation radiation-medicine projects is provided to establish or enhance radiation medicine worldwide. (author)

  2. 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

    International Nuclear Information System (INIS)

    Sayler, E; Harrison, A; Eldredge-Hindy, H; Dinome, J; Munro, S; Anne, R; Comber, E; Lockamy, V

    2014-01-01

    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

  3. The IPEM code of practice for determination of the reference air kerma rate for HDR 192Ir brachytherapy sources based on the NPL air kerma standard

    International Nuclear Information System (INIS)

    Bidmead, A M; Sander, T; Nutbrown, R F; Locks, S M; Lee, C D; Aird, E G A; Flynn, A

    2010-01-01

    This paper contains the recommendations of the high dose rate (HDR) brachytherapy working party of the UK Institute of Physics and Engineering in Medicine (IPEM). The recommendations consist of a Code of Practice (COP) for the UK for measuring the reference air kerma rate (RAKR) of HDR 192 Ir brachytherapy sources. In 2004, the National Physical Laboratory (NPL) commissioned a primary standard for the realization of RAKR of HDR 192 Ir brachytherapy sources. This has meant that it is now possible to calibrate ionization chambers directly traceable to an air kerma standard using an 192 Ir source (Sander and Nutbrown 2006 NPL Report DQL-RD 004 (Teddington: NPL) http://publications.npl.co.uk). In order to use the source specification in terms of either RAKR, .K R (ICRU 1985 ICRU Report No 38 (Washington, DC: ICRU); ICRU 1997 ICRU Report No 58 (Bethesda, MD: ICRU)), or air kerma strength, S K (Nath et al 1995 Med. Phys. 22 209-34), it has been necessary to develop algorithms that can calculate the dose at any point around brachytherapy sources within the patient tissues. The AAPM TG-43 protocol (Nath et al 1995 Med. Phys. 22 209-34) and the 2004 update TG-43U1 (Rivard et al 2004 Med. Phys. 31 633-74) have been developed more fully than any other protocol and are widely used in commercial treatment planning systems. Since the TG-43 formalism uses the quantity air kerma strength, whereas this COP uses RAKR, a unit conversion from RAKR to air kerma strength was included in the appendix to this COP. It is recommended that the measured RAKR determined with a calibrated well chamber traceable to the NPL 192 Ir primary standard is used in the treatment planning system. The measurement uncertainty in the source calibration based on the system described in this COP has been reduced considerably compared to other methods based on interpolation techniques.

  4. Radiotherapy of bronchogenic carcinoma

    International Nuclear Information System (INIS)

    Heilmann, H.P.

    1982-01-01

    Radiotherapy of branchogenic carcinoma comprises; palliative treatment, postoperative or pre-operative radiotherapy, radiotherapy as part of a combination of chemotherapy and radiotherapy of small cell carcinoma and curative radiotherapy of non-operable non-small cell carcinoma. Atelectasis and obstruction are indications for palliative radiotherapy. Postoperative radiotherapy is given only in cases of incomplete resection or mediastinal metastases. In the treatment of small cell carcinoma by combined irradiation and chemotherapy the mediastinum and primary tumour are irradiated, generally after chemotherapy, and the C.N.S. receives prophylactic radiotherapy. Curative radiotherapy is indicated in cases of non-operable small cell carcinoma. Irradiation with doses of 60-70 Gy produced 5-years-survival rates of 10-14% in cases classified as T 1 -T 2 N 0 M 0 . (orig.) [de

  5. 3D workflow for HDR image capture of projection systems and objects for CAVE virtual environments authoring with wireless touch-sensitive devices

    Science.gov (United States)

    Prusten, Mark J.; McIntyre, Michelle; Landis, Marvin

    2006-02-01

    A 3D workflow pipeline is presented for High Dynamic Range (HDR) image capture of projected scenes or objects for presentation in CAVE virtual environments. The methods of HDR digital photography of environments vs. objects are reviewed. Samples of both types of virtual authoring being the actual CAVE environment and a sculpture are shown. A series of software tools are incorporated into a pipeline called CAVEPIPE, allowing for high-resolution objects and scenes to be composited together in natural illumination environments [1] and presented in our CAVE virtual reality environment. We also present a way to enhance the user interface for CAVE environments. The traditional methods of controlling the navigation through virtual environments include: glove, HUD's and 3D mouse devices. By integrating a wireless network that includes both WiFi (IEEE 802.11b/g) and Bluetooth (IEEE 802.15.1) protocols the non-graphical input control device can be eliminated. Therefore wireless devices can be added that would include: PDA's, Smart Phones, TabletPC's, Portable Gaming consoles, and PocketPC's.

  6. The Oryza sativa Regulator HDR1 Associates with the Kinase OsK4 to Control Photoperiodic Flowering.

    Directory of Open Access Journals (Sweden)

    Xuehui Sun

    2016-03-01

    Full Text Available Rice is a facultative short-day plant (SDP, and the regulatory pathways for flowering time are conserved, but functionally modified, in Arabidopsis and rice. Heading date 1 (Hd1, an ortholog of Arabidopsis CONSTANS (CO, is a key regulator that suppresses flowering under long-day conditions (LDs, but promotes flowering under short-day conditions (SDs by influencing the expression of the florigen gene Heading date 3a (Hd3a. Another key regulator, Early heading date 1 (Ehd1, is an evolutionarily unique gene with no orthologs in Arabidopsis, which acts as a flowering activator under both SD and LD by promoting the rice florigen genes Hd3a and RICE FLOWERING LOCUST 1 (RFT1. Here, we report the isolation and characterization of the flowering regulator Heading Date Repressor1 (HDR1 in rice. The hdr1 mutant exhibits an early flowering phenotype under natural LD in a paddy field in Beijing, China (39°54'N, 116°23'E, as well as under LD but not SD in a growth chamber, indicating that HDR1 may functionally regulate flowering time via the photoperiod-dependent pathway. HDR1 encodes a nuclear protein that is most active in leaves and floral organs and exhibits a typical diurnal expression pattern. We determined that HDR1 is a novel suppressor of flowering that upregulates Hd1 and downregulates Ehd1, leading to the downregulation of Hd3a and RFT1 under LDs. We have further identified an HDR1-interacting kinase, OsK4, another suppressor of rice flowering under LDs. OsK4 acts similarly to HDR1, suppressing flowering by upregulating Hd1 and downregulating Ehd1 under LDs, and OsK4 can phosphorylate HD1 with HDR1 presents. These results collectively reveal the transcriptional regulators of Hd1 for the day-length-dependent control of flowering time in rice.

  7. A segmentation and point-matching enhanced efficient deformable image registration method for dose accumulation between HDR CT images

    International Nuclear Information System (INIS)

    Zhen, Xin; Chen, Haibin; Zhou, Linghong; Yan, Hao; Jiang, Steve; Jia, Xun; Gu, Xuejun; Mell, Loren K; Yashar, Catheryn M; Cervino, Laura

    2015-01-01

    Deformable image registration (DIR) of fractional high-dose-rate (HDR) CT images is challenging due to the presence of applicators in the brachytherapy image. Point-to-point correspondence fails because of the undesired deformation vector fields (DVF) propagated from the applicator region (AR) to the surrounding tissues, which can potentially introduce significant DIR errors in dose mapping. This paper proposes a novel segmentation and point-matching enhanced efficient DIR (named SPEED) scheme to facilitate dose accumulation among HDR treatment fractions. In SPEED, a semi-automatic seed point generation approach is developed to obtain the incremented fore/background point sets to feed the random walks algorithm, which is used to segment and remove the AR, leaving empty AR cavities in the HDR CT images. A feature-based ‘thin-plate-spline robust point matching’ algorithm is then employed for AR cavity surface points matching. With the resulting mapping, a DVF defining on each voxel is estimated by B-spline approximation, which serves as the initial DVF for the subsequent Demons-based DIR between the AR-free HDR CT images. The calculated DVF via Demons combined with the initial one serve as the final DVF to map doses between HDR fractions. The segmentation and registration accuracy are quantitatively assessed by nine clinical HDR cases from three gynecological cancer patients. The quantitative analysis and visual inspection of the DIR results indicate that SPEED can suppress the impact of applicator on DIR, and accurately register HDR CT images as well as deform and add interfractional HDR doses. (paper)

  8. A segmentation and point-matching enhanced efficient deformable image registration method for dose accumulation between HDR CT images

    Science.gov (United States)

    Zhen, Xin; Chen, Haibin; Yan, Hao; Zhou, Linghong; Mell, Loren K.; Yashar, Catheryn M.; Jiang, Steve; Jia, Xun; Gu, Xuejun; Cervino, Laura

    2015-04-01

    Deformable image registration (DIR) of fractional high-dose-rate (HDR) CT images is challenging due to the presence of applicators in the brachytherapy image. Point-to-point correspondence fails because of the undesired deformation vector fields (DVF) propagated from the applicator region (AR) to the surrounding tissues, which can potentially introduce significant DIR errors in dose mapping. This paper proposes a novel segmentation and point-matching enhanced efficient DIR (named SPEED) scheme to facilitate dose accumulation among HDR treatment fractions. In SPEED, a semi-automatic seed point generation approach is developed to obtain the incremented fore/background point sets to feed the random walks algorithm, which is used to segment and remove the AR, leaving empty AR cavities in the HDR CT images. A feature-based ‘thin-plate-spline robust point matching’ algorithm is then employed for AR cavity surface points matching. With the resulting mapping, a DVF defining on each voxel is estimated by B-spline approximation, which serves as the initial DVF for the subsequent Demons-based DIR between the AR-free HDR CT images. The calculated DVF via Demons combined with the initial one serve as the final DVF to map doses between HDR fractions. The segmentation and registration accuracy are quantitatively assessed by nine clinical HDR cases from three gynecological cancer patients. The quantitative analysis and visual inspection of the DIR results indicate that SPEED can suppress the impact of applicator on DIR, and accurately register HDR CT images as well as deform and add interfractional HDR doses.

  9. Evaluation of the Kerma at the entrance of the labyrin thin in facilities with Co-60 HDR brachytherapy

    International Nuclear Information System (INIS)

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

    2013-01-01

    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)

  10. Bystander effects and radiotherapy.

    Science.gov (United States)

    Marín, Alicia; Martín, Margarita; Liñán, Olga; Alvarenga, Felipe; López, Mario; Fernández, Laura; Büchser, David; Cerezo, Laura

    2015-01-01

    Radiation-induced bystander effects are defined as biological effects expressed after irradiation by cells whose nuclei have not been directly irradiated. These effects include DNA damage, chromosomal instability, mutation, and apoptosis. There is considerable evidence that ionizing radiation affects cells located near the site of irradiation, which respond individually and collectively as part of a large interconnected web. These bystander signals can alter the dynamic equilibrium between proliferation, apoptosis, quiescence or differentiation. The aim of this review is to examine the most important biological effects of this phenomenon with regard to areas of major interest in radiotherapy. Such aspects include radiation-induced bystander effects during the cell cycle under hypoxic conditions when administering fractionated modalities or combined radio-chemotherapy. Other relevant aspects include individual variation and genetics in toxicity of bystander factors and normal tissue collateral damage. In advanced radiotherapy techniques, such as intensity-modulated radiation therapy (IMRT), the high degree of dose conformity to the target volume reduces the dose and, therefore, the risk of complications, to normal tissues. However, significant doses can accumulate out-of-field due to photon scattering and this may impact cellular response in these regions. Protons may offer a solution to reduce out-of-field doses. The bystander effect has numerous associated phenomena, including adaptive response, genomic instability, and abscopal effects. Also, the bystander effect can influence radiation protection and oxidative stress. It is essential that we understand the mechanisms underlying the bystander effect in order to more accurately assess radiation risk and to evaluate protocols for cancer radiotherapy.

  11. Clinical-dosimetric analysis of measures of dysphagia including gastrostomy-tube dependence among head and neck cancer patients treated definitively by intensity-modulated radiotherapy with concurrent chemotherapy

    International Nuclear Information System (INIS)

    Li, Baoqing; Chen, Allen M; Li, Dan; Lau, Derick H; Farwell, D Gregory; Luu, Quang; Rocke, David M; Newman, Kathleen; Courquin, Jean; Purdy, James A

    2009-01-01

    To investigate the association between dose to various anatomical structures and dysphagia among patients with head and neck cancer treated by definitive intensity-modulated radiotherapy (IMRT) and concurrent chemotherapy. Thirty-nine patients with squamous cancer of the head and neck were treated by definitive concurrent chemotherapy and IMRT to a median dose of 70 Gy (range, 68 to 72). In each patient, a gastrostomy tube (GT) was prophylacticly placed prior to starting treatment. Prolonged GT dependence was defined as exceeding the median GT duration of 192 days. Dysphagia was scored using standardized quality-of-life instruments. Dose-volume histogram (DVH) data incorporating the superior/middle pharyngeal constrictors (SMPC), inferior pharyngeal constrictor (IPC), cricoid pharyngeal inlet (CPI), and cervical esophagus (CE) were analyzed in relation to prolonged GT dependence, dysphagia, and weight loss. At 3 months and 6 months after treatment, 87% and 44% of patients, respectively, were GT dependent. Spearman's ρ analysis identified statistical correlations (p < 0.05) between prolonged GT dependence or high grade dysphagia with IPC V65, IPC V60, IPC Dmean, and CPI Dmax. Logistic regression model showed that IPC V65 > 30%, IPC V60 > 60%, IPC Dmean > 60 Gy, and CPI Dmax > 62 Gy predicted for greater than 50% probability of prolonged GT dependence. Our analysis suggests that adhering to the following parameters may decrease the risk of prolonged GT dependence and dysphagia: IPC V65 < 15%, IPC V60 < 40%, IPC Dmean < 55 Gy, and CPI Dmax < 60 Gy

  12. HDR intralumenal brachytherapy in bronchial cancer: review of our experience

    International Nuclear Information System (INIS)

    Muto, P.; Ravo, V.; Muschera, R.

    1996-01-01

    The main indications for brachytherapy in the treatment of endobronchial cancer are dyspnea. postobstructive pneumonia and atelectasis, cough and hemoptysis resulting from broncus obstruction by exophytic intralumenal tumor growth. High Dose Rate intralumenal brachytherapy (HDRBT) may be combined with external beam radiotherapy (EBRT), in particular as almost all tumors are too large for HDRBT alone. From January 1992 to September 1995 we treated 268 patients affected by bronchial cancer, with EBRT combined with HDRBT. All patients were staged as IIIa-IIIb-IV but KPS was >60 and expectancy of life > than 3 months. After bronchoscopy and Tc simulation we found that almost 10% of patients were downstaged. Treatment was always realized delivering 60 Gy to the tumour volume and 50 Gy to the mediastinal structures with EBRT. Brachytherapy was performed during the radiotherapy course. In 38 patients HDRBT was realized just one time, at the beginning of EBRT, with a dose of 10 Gy calculated at 1cm from the central axis of the catheter. In 47 HDRBT was performed twice (at the beginning and at the end of EBRT) with a dose of 7 Gy calculated at 1 cm from the central axis. From 1994 we started a 3 fractions protocol (Timing: days 1.15.30) with a dose of 5 Gy calculated at 0.5 cm from the axis. Of the 183 patients introduced in the protocol 170 received the three fractions of HDRBT and 13 were excluded from the study for personal or clinical reasons. In 97% of cases the application did not need general anesthesia; local anesthesia has been sufficient supplemented by some drug for sedation and coughing. Anyway both bronchoscopy and HDRBT (with anterior-posterior and lateral chest X-ray) are performed in the same shielded room without the necessity of displacing the patient. In almost 60% of treatments we used just one endobronchial applicator. In case of tumor involvement of the carina, two applicators were introduced. By this a larger tumor volume can be treated with adequate

  13. Evaluation of the response of concurrent high dose rate intracavitary brachytherapy with external beam radiotherapy in management of early stage carcinoma cervix.

    Science.gov (United States)

    Patidar, Arvind Kumar; Kumar, H S; Walke, Rahul V; Hirapara, Pushpendra H; Jakhar, Shankar Lal; Bardia, M R

    2012-10-01

    To evaluate local disease control and early complications of concomitant brachytherapy with external beam-radiotherapy in early stage carcinoma cervix. Fifty patients of early stage carcinoma cervix (FIGO-IB/IIA) were randomly divided into study group concomitant external beam irradiation (EBRT) and HDR-ICBT (intra-cavitary brachytherapy, xrt = 50 Gy/25 Fr, HDR 5.2 Gy*5 Fr) and the control group EBRT followed by HDR-ICBT (xrt = 50 Gy/25 Fr, HDR 7.5 Gy*3 Fr). Acute reactions and local disease response were compared between treatment and at 6-month follow up. Median overall treatment times were 38 and 61 days in the study and the control groups, respectively. Acute skin reactions and diarrhea were more in the study but manageable. At the completion of the study, there were 80 and 68 % complete responses, 16 and 20 % partial responses, 0 and 8 % stable diseases in the study group and the control group, respectively. Response was better in the study group but statistically insignificant. Larger number of patients and longer follow up are required to arrive at concrete conclusion.

  14. Inverse treatment planning based on MRI for HDR prostate brachytherapy

    International Nuclear Information System (INIS)

    Citrin, Deborah; Ning, Holly; Guion, Peter; Li Guang; Susil, Robert C.; Miller, Robert W.; Lessard, Etienne; Pouliot, Jean; Xie Huchen; Capala, Jacek; Coleman, C. Norman; Camphausen, Kevin; Menard, Cynthia

    2005-01-01

    Purpose: To develop and optimize a technique for inverse treatment planning based solely on magnetic resonance imaging (MRI) during high-dose-rate brachytherapy for prostate cancer. Methods and materials: Phantom studies were performed to verify the spatial integrity of treatment planning based on MRI. Data were evaluated from 10 patients with clinically localized prostate cancer who had undergone two high-dose-rate prostate brachytherapy boosts under MRI guidance before and after pelvic radiotherapy. Treatment planning MRI scans were systematically evaluated to derive a class solution for inverse planning constraints that would reproducibly result in acceptable target and normal tissue dosimetry. Results: We verified the spatial integrity of MRI for treatment planning. MRI anatomic evaluation revealed no significant displacement of the prostate in the left lateral decubitus position, a mean distance of 14.47 mm from the prostatic apex to the penile bulb, and clear demarcation of the neurovascular bundles on postcontrast imaging. Derivation of a class solution for inverse planning constraints resulted in a mean target volume receiving 100% of the prescribed dose of 95.69%, while maintaining a rectal volume receiving 75% of the prescribed dose of <5% (mean 1.36%) and urethral volume receiving 125% of the prescribed dose of <2% (mean 0.54%). Conclusion: Systematic evaluation of image spatial integrity, delineation uncertainty, and inverse planning constraints in our procedure reduced uncertainty in planning and treatment

  15. National arrangements for radiotherapy

    International Nuclear Information System (INIS)

    2007-01-01

    After a presentation of several letters exchanged between the French health ministry and public agencies in charge of public health or nuclear safety after a radiotherapy accident in Epinal, this report comments the evolution of needs in cancerology care and the place given to radiotherapy. It outlines the technological and organisational evolution of radiotherapy and presents the distribution of radiotherapy equipment, of radio-therapists and other radiotherapy professionals in France. Within the context of radiotherapy accidents which occurred in 2007, it presents the regulatory arrangements which aimed at improving the safety, short term and middle term arrangements which are needed to support and structure radiotherapy practice quality. It stresses the fact that the system will deeply evolve by implementing a radiotherapy vigilance arrangement and a permanent follow-on and adaptation plan based on surveys and the creation of a national committee

  16. Radiotherapy of malignant lymphomas

    Energy Technology Data Exchange (ETDEWEB)

    Kujawska, J [Instytut Onkologii, Krakow (Poland)

    1979-01-01

    The paper discusses current views on the role of radiotherapy in the treatment of patients with malignant lymphomas. Principles of radiotherapy employed in the Institute of Oncology in Cracow in case of patients with malignant lymphomas are also presented.

  17. Management of a HDR brachytherapy system in the Hospital Juarez of Mexico

    International Nuclear Information System (INIS)

    Serrano F, A.G.; Ramirez R, G.; Gil G, R.; Azorin N, J.; Rivera M, T.

    2007-01-01

    Full text: In the Hospital Juarez of Mexico, it is carried out a project to implement a Brachytherapy system with high dose rate (HDR) through a Management quality program. In our work center this treatment modality in patients with cervicouterine cancer is used (CaCu), and constantly it is necessary to carry out improvements in the procedures, with the purpose of optimizing them and in consequence to complete the principles of the Radiological Protection, guaranteeing this way, an attention with the quality and safety, such that allow to diminish the risks to the patients and to assure that the received dose in critical organs it finds inside the permitted therapeutic limits, without commit the radiosensitive response of healthy organs. In this work an analysis of the implementation of this system is presented, detailing the procedures so much in the technological infrastructure like human and indicating the necessary technical and operative requirements to reach an adequate practice in HDR brachytherapy. (Author)

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

    International Nuclear Information System (INIS)

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

    2014-01-01

    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

  19. 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.

  20. 3-D conformal HDR brachytherapy as monotherapy for localized prostate cancer. A pilot study

    International Nuclear Information System (INIS)

    Martin, T.; Baltas, D.; Kurek, R.; Roeddiger, S.; Kontova, M.; Anagnostopoulos, G.; Skazikis, G.; Zamboglou, N.; Dannenberg, T.; Buhleier, T.; Tunn, U.

    2004-01-01

    Purpose: pilot study to evaluate feasibility, acute toxicity and conformal quality of three-dimensional (3-D) conformal high-dose-rate (HDR) brachytherapy as monotherapy for localized prostate cancer using intraoperative real-time planning. Patients and methods: between 05/2002 and 05/2003, 52 patients with prostate cancer, prostate-specific antigen (PSA) ≤ 10 ng/ml, Gleason score ≤ 7 and clinical stage ≤ T2a were treated. Median PSA was 6.4 ng/ml and median Gleason score 5. 24/52 patients had stage T1c and 28/52 stage T2a. For transrectal ultrasound-(TRUS-)guided transperineal implantation of flexible plastic needles into the prostate, the real-time HDR planning system SWIFT trademark was used. After implantation, CT-based 3-D postplanning was performed. All patients received one implant for four fractions of HDR brachytherapy in 48 h using a reference dose (D ref ) of 9.5 Gy to a total dose of 38.0 Gy. Dose-volume histograms (DVHs) were analyzed to evaluate the conformal quality of each implant using D 90 , D 10 urethra, and D 10 rectum. Acute toxicity was evaluated using the CTC (common toxicity criteria) scales. Results: median D 90 was 106% of D ref (range: 93-115%), median D 10 urethra 159% of D ref (range: 127-192%), and median D 10 rectum 55% of D ref (range: 35-68%). Median follow-up is currently 8 months. In 2/52 patients acute grade 3 genitourinary toxicity was observed. No gastrointestinal toxicity > grade 1 occurred. Conclusion: 3-D conformal HDR brachytherapy as monotherapy using intraoperative real-time planning is a feasible and highly conformal treatment for localized prostate cancer associated with minimal acute toxicity. Longer follow-up is needed to evaluate late toxicity and biochemical control. (orig.)

  1. Is there any place for LDR brachytherapy for head and neck carcinomas in HDR era?

    OpenAIRE

    Fijuth, Jacek

    2009-01-01

    In Poland, the classical LDR brachytherapy for head and neck carcinomas with Ir-192 wires or hairpins has completely disappeared some time ago after 30 years of successful clinical use. Can this technique be fully and safely replaced by HDR or PDR application? This option seems attractive because of new possibilities of 3D reconstruction and computer real-time treatment planning and optimization. However, in my opinion, long time is needed to get a clinical and scientific experience that has ...

  2. SU-E-J-270: Study of PET Response to HDR Brachytherapy of Rectal Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Hobbs, R; Le, Y; Armour, E; Efron, J; Azad, N; Wahl, R; Gearhart, S; Herman, J [Johns Hopkins University, Baltimore, MD (United States)

    2014-06-01

    Purpose: Dose-response studies in radiation therapy are typically using single response values for tumors across ensembles of tumors. Using the high dose rate (HDR) treatment plan dose grid and pre- and post-therapy FDG-PET images, we look for correlations between voxelized dose and FDG uptake response in individual tumors. Methods: Fifteen patients were treated for localized rectal cancer using 192Ir HDR brachytherapy in conjunction with surgery. FDG-PET images were acquired before HDR therapy and 6–8 weeks after treatment (prior to surgery). Treatment planning was done on a commercial workstation and the dose grid was calculated. The two PETs and the treatment dose grid were registered to each other using non-rigid registration. The difference in PET SUV values before and after HDR was plotted versus absorbed radiation dose for each voxel. The voxels were then separated into bins for every 400 cGy of absorbed dose and the bin average values plotted similarly. Results: Individual voxel doses did not correlate with PET response; however, when group into tumor subregions corresponding to dose bins, eighty percent of the patients showed a significant positive correlation (R2 > 0) between PET uptake difference in the targeted region and the absorbed dose. Conclusion: By considering larger ensembles of voxels, such as organ average absorbed dose or the dose bins considered here, valuable information may be obtained. The dose-response correlations as measured by FDG-PET difference potentially underlines the importance of FDG-PET as a measure of response, as well as the value of voxelized information.

  3. Stereotactic radiotherapy for vestibular schwannoma

    DEFF Research Database (Denmark)

    Muzevic, Dario; Legcevic, Jelena; Splavski, Bruno

    2014-01-01

    BACKGROUND: Vestibular schwannomas (acoustic neuromas) are common benign tumours that arise from the Schwann cells of the vestibular nerve. Management options include observation with neuroradiological follow-up, microsurgical resection and stereotactic radiotherapy. OBJECTIVES: To assess...... the effect of stereotactic radiotherapy compared to observation, microsurgical resection, any other treatment modality, or a combination of two or more of the above approaches for vestibular schwannoma. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials; PubMed; EMBASE; CINAHL......; Web of Science; CAB Abstracts; ISRCTN and additional sources for published and unpublished trials. The date of the search was 24 July 2014. SELECTION CRITERIA: Randomised controlled trials (RCTs) exploring the efficacy of stereotactic radiotherapy compared with observation alone, microsurgical...

  4. Hyperthermia and radiotherapy

    International Nuclear Information System (INIS)

    Fitspatrick, C.

    1990-01-01

    Hyperthermia and radiotherapy have for long been used to assist in the control of tumours, either as separate entities, or, in a combined treatment scheme. This paper outlines why hyperthermia works, thermal dose and the considerations required in the timing when hyperthermia is combined with radiotherapy. Previously reported results for hyperthermia and radiotherapy used together are also presented. 8 refs., 8 tabs

  5. Application of the Monte Carlo integration method in calculations of dose distributions in HDR-Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Baltas, D; Geramani, K N; Ioannidis, G T; Kolotas, C; Zamboglou, N [Strahlenklinik, Stadtische Kliniken Offenbach, Offenbach (Germany); Giannouli, S [Department of Electrical and Computer Engineering, National Technical University of Athens, Athens (Greece)

    1999-12-31

    Source anisotropy is a very important factor in brachytherapy quality assurance of high dose rate HDR Ir 192 afterloading stepping sources. If anisotropy is not taken into account then doses received by a brachytherapy patient in certain directions can be in error by a clinically significant amount. Experimental measurements of anisotropy are very labour intensive. We have shown that within acceptable limits of accuracy, Monte Carlo integration (MCI) of a modified Sievert integral (3D generalisation) can provide the necessary data within a much shorter time scale than can experiments. Hence MCI can be used for routine quality assurance schedules whenever a new design of HDR or PDR Ir 192 is used for brachytherapy afterloading. Our MCI calculation results are comparable with published experimental data and Monte Carlo simulation data for microSelectron and VariSource Ir 192 sources. We have shown not only that MCI offers advantages over alternative numerical integration methods, but also that treating filtration coefficients as radial distance-dependent functions improves Sievert integral accuracy at low energies. This paper also provides anisotropy data for three new Ir 192 sources, one for microSelectron-HDR and two for the microSelectron-PDR, for which data currently is not available. The information we have obtained in this study can be incorporated into clinical practice.

  6. 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.

  7. 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.

  8. Vibrational experiments at the HDR [Heissdampfreaktor]: SHAG results and planning for SHAM

    International Nuclear Information System (INIS)

    Kot, C.A.; Malcher, L.; Steinhilber, H.

    1987-01-01

    As part of the second phase of vibrational/earthquake investigations at the HDR (Heissdampfreaktor) Test Facility in Kahl/Main, FRG, high-level shaker tests (SHAG) were performed during June and July 1986 using a coast-down shaker capable of generating 1000 tons of force. The purpose of these experiments was to investigate full-scale structural response, soil/structure interaction, and piping and equipment response under strong excitation conditions. While global safety considerations imposed load limitations, the HDR soil/structure system was nevertheless tested to incipient failure. The performance of pipe support systems in as many as seven different multiple support pipe hanger configurations, ranging from flexible to stiff systems, was evaluated in the tests. Data obtained in the tests are used to validate analysis methods. The vibrational/earthquake investigations at the HDR are continuing with the SHAM experiments, planned for the spring of 1988. In these experiments the VKL piping loop will be subjected to direct multiple-point excitation at extremely high levels. The objective is to investigate different pipe support configurations at extreme loading, to establish seismic margins for piping, and to investigate possible failure/plastification modes in an in situ piping system

  9. Interactive multiobjective optimization for anatomy-based three-dimensional HDR brachytherapy

    Science.gov (United States)

    Ruotsalainen, Henri; Miettinen, Kaisa; Palmgren, Jan-Erik; Lahtinen, Tapani

    2010-08-01

    In this paper, we present an anatomy-based three-dimensional dose optimization approach for HDR brachytherapy using interactive multiobjective optimization (IMOO). In brachytherapy, the goals are to irradiate a tumor without causing damage to healthy tissue. These goals are often conflicting, i.e. when one target is optimized the other will suffer, and the solution is a compromise between them. IMOO is capable of handling multiple and strongly conflicting objectives in a convenient way. With the IMOO approach, a treatment planner's knowledge is used to direct the optimization process. Thus, the weaknesses of widely used optimization techniques (e.g. defining weights, computational burden and trial-and-error planning) can be avoided, planning times can be shortened and the number of solutions to be calculated is small. Further, plan quality can be improved by finding advantageous trade-offs between the solutions. In addition, our approach offers an easy way to navigate among the obtained Pareto optimal solutions (i.e. different treatment plans). When considering a simulation model of clinical 3D HDR brachytherapy, the number of variables is significantly smaller compared to IMRT, for example. Thus, when solving the model, the CPU time is relatively short. This makes it possible to exploit IMOO to solve a 3D HDR brachytherapy optimization problem. To demonstrate the advantages of IMOO, two clinical examples of optimizing a gynecologic cervix cancer treatment plan are presented.

  10. Interactive multiobjective optimization for anatomy-based three-dimensional HDR brachytherapy

    International Nuclear Information System (INIS)

    Ruotsalainen, Henri; Miettinen, Kaisa; Palmgren, Jan-Erik; Lahtinen, Tapani

    2010-01-01

    In this paper, we present an anatomy-based three-dimensional dose optimization approach for HDR brachytherapy using interactive multiobjective optimization (IMOO). In brachytherapy, the goals are to irradiate a tumor without causing damage to healthy tissue. These goals are often conflicting, i.e. when one target is optimized the other will suffer, and the solution is a compromise between them. IMOO is capable of handling multiple and strongly conflicting objectives in a convenient way. With the IMOO approach, a treatment planner's knowledge is used to direct the optimization process. Thus, the weaknesses of widely used optimization techniques (e.g. defining weights, computational burden and trial-and-error planning) can be avoided, planning times can be shortened and the number of solutions to be calculated is small. Further, plan quality can be improved by finding advantageous trade-offs between the solutions. In addition, our approach offers an easy way to navigate among the obtained Pareto optimal solutions (i.e. different treatment plans). When considering a simulation model of clinical 3D HDR brachytherapy, the number of variables is significantly smaller compared to IMRT, for example. Thus, when solving the model, the CPU time is relatively short. This makes it possible to exploit IMOO to solve a 3D HDR brachytherapy optimization problem. To demonstrate the advantages of IMOO, two clinical examples of optimizing a gynecologic cervix cancer treatment plan are presented.

  11. Near constant-time optimal piecewise LDR to HDR inverse tone mapping

    Science.gov (United States)

    Chen, Qian; Su, Guan-Ming; Yin, Peng

    2015-02-01

    In a backward compatible HDR image/video compression, it is a general approach to reconstruct HDR from compressed LDR as a prediction to original HDR, which is referred to as inverse tone mapping. Experimental results show that 2- piecewise 2nd order polynomial has the best mapping accuracy than 1 piece high order or 2-piecewise linear, but it is also the most time-consuming method because to find the optimal pivot point to split LDR range to 2 pieces requires exhaustive search. In this paper, we propose a fast algorithm that completes optimal 2-piecewise 2nd order polynomial inverse tone mapping in near constant time without quality degradation. We observe that in least square solution, each entry in the intermediate matrix can be written as the sum of some basic terms, which can be pre-calculated into look-up tables. Since solving the matrix becomes looking up values in tables, computation time barely differs regardless of the number of points searched. Hence, we can carry out the most thorough pivot point search to find the optimal pivot that minimizes MSE in near constant time. Experiment shows that our proposed method achieves the same PSNR performance while saving 60 times computation time compared to the traditional exhaustive search in 2-piecewise 2nd order polynomial inverse tone mapping with continuous constraint.

  12. NOTE: Monte Carlo evaluation of kerma in an HDR brachytherapy bunker

    Science.gov (United States)

    Pérez-Calatayud, J.; Granero, D.; Ballester, F.; Casal, E.; Crispin, V.; Puchades, V.; León, A.; Verdú, G.

    2004-12-01

    In recent years, the use of high dose rate (HDR) after-loader machines has greatly increased due to the shift from traditional Cs-137/Ir-192 low dose rate (LDR) to HDR brachytherapy. The method used to calculate the required concrete and, where appropriate, lead shielding in the door is based on analytical methods provided by documents published by the ICRP, the IAEA and the NCRP. The purpose of this study is to perform a more realistic kerma evaluation at the entrance maze door of an HDR bunker using the Monte Carlo code GEANT4. The Monte Carlo results were validated experimentally. The spectrum at the maze entrance door, obtained with Monte Carlo, has an average energy of about 110 keV, maintaining a similar value along the length of the maze. The comparison of results from the aforementioned values with the Monte Carlo ones shows that results obtained using the albedo coefficient from the ICRP document more closely match those given by the Monte Carlo method, although the maximum value given by MC calculations is 30% greater.

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

    International Nuclear Information System (INIS)

    Fonseca, Gabriel P.; Yoriyaz, Helio; Antunes, Paula C.G.; Siqueira, Paulo T.D.; Rubo, Rodrigo; Ferreira, Louise A.

    2011-01-01

    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)

  14. 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.

  15. 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)

  16. The effect of split pixel HDR image sensor technology on MTF measurements

    Science.gov (United States)

    Deegan, Brian M.

    2014-03-01

    Split-pixel HDR sensor technology is particularly advantageous in automotive applications, because the images are captured simultaneously rather than sequentially, thereby reducing motion blur. However, split pixel technology introduces artifacts in MTF measurement. To achieve a HDR image, raw images are captured from both large and small sub-pixels, and combined to make the HDR output. In some cases, a large sub-pixel is used for long exposure captures, and a small sub-pixel for short exposures, to extend the dynamic range. The relative size of the photosensitive area of the pixel (fill factor) plays a very significant role in the output MTF measurement. Given an identical scene, the MTF will be significantly different, depending on whether you use the large or small sub-pixels i.e. a smaller fill factor (e.g. in the short exposure sub-pixel) will result in higher MTF scores, but significantly greater aliasing. Simulations of split-pixel sensors revealed that, when raw images from both sub-pixels are combined, there is a significant difference in rising edge (i.e. black-to-white transition) and falling edge (white-to-black) reproduction. Experimental results showed a difference of ~50% in measured MTF50 between the falling and rising edges of a slanted edge test chart.

  17. Independent verification of the delivered dose in High-Dose Rate (HDR) brachytherapy

    International Nuclear Information System (INIS)

    Portillo, P.; Feld, D.; Kessler, J.

    2009-01-01

    An important aspect of a Quality Assurance program in Clinical Dosimetry is an independent verification of the dosimetric calculation done by the Treatment Planning System for each radiation treatment. The present paper is aimed at creating a spreadsheet for the verification of the dose recorded at a point of an implant with radioactive sources and HDR in gynecological injuries. An 192 Ir source automatic differed loading equipment, GammaMedplus model, Varian Medical System with HDR installed at the Angel H. Roffo Oncology Institute has been used. The planning system implemented for getting the dose distribution is the BraquiVision. The sources coordinates as well as those of the calculation point (Rectum) are entered into the Excel-devised verification program by assuming the existence of a point source in each one of the applicators' positions. Such calculation point has been selected as the rectum is an organ at risk, therefore determining the treatment planning. The dose verification is performed at points standing at a sources distance having at least twice the active length of such sources, so they may be regarded as point sources. Most of the sources used in HDR brachytherapy with 192 Ir have a 5 mm active length for all equipment brands. Consequently, the dose verification distance must be at least of 10 mm. (author)

  18. 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.

  19. Impact of using linear optimization models in dose planning for HDR brachytherapy

    International Nuclear Information System (INIS)

    Holm, Aasa; Larsson, Torbjoern; Carlsson Tedgren, Aasa

    2012-01-01

    Purpose: Dose plans generated with optimization models hitherto used in high-dose-rate (HDR) brachytherapy have shown a tendency to yield longer dwell times than manually optimized plans. Concern has been raised for the corresponding undesired hot spots, and various methods to mitigate these have been developed. The hypotheses upon this work is based are (a) that one cause for the long dwell times is the use of objective functions comprising simple linear penalties and (b) that alternative penalties, as these are piecewise linear, would lead to reduced length of individual dwell times. Methods: The characteristics of the linear penalties and the piecewise linear penalties are analyzed mathematically. Experimental comparisons between the two types of penalties are carried out retrospectively for a set of prostate cancer patients. Results: When the two types of penalties are compared, significant changes can be seen in the dwell times, while most dose-volume parameters do not differ significantly. On average, total dwell times were reduced by 4.2%, with a reduction of maximum dwell times by 25%, when the alternative penalties were used. Conclusions: The use of linear penalties in optimization models for HDR brachytherapy is one cause for the undesired long dwell times that arise in mathematically optimized plans. By introducing alternative penalties, a significant reduction in dwell times can be achieved for HDR brachytherapy dose plans. Although various measures for mitigating the long dwell times are already available, the observation that linear penalties contribute to their appearance is of fundamental interest.

  20. Design and implementation of a film dosimetry audit tool for comparison of planned and delivered dose distributions in high dose rate (HDR) brachytherapy

    Science.gov (United States)

    Palmer, Antony L.; Lee, Chris; Ratcliffe, Ailsa J.; Bradley, David; Nisbet, Andrew

    2013-10-01

    A novel phantom is presented for ‘full system’ dosimetric audit comparing planned and delivered dose distributions in HDR gynaecological brachytherapy, using clinical treatment applicators. The brachytherapy applicator dosimetry test object consists of a near full-scatter water tank with applicator and film supports constructed of Solid Water, accommodating any typical cervix applicator. Film dosimeters are precisely held in four orthogonal planes bisecting the intrauterine tube, sampling dose distributions in the high risk clinical target volume, points A and B, bladder, rectum and sigmoid. The applicator position is fixed prior to CT scanning and through treatment planning and irradiation. The CT data is acquired with the applicator in a near clinical orientation to include applicator reconstruction in the system test. Gamma analysis is used to compare treatment planning system exported RTDose grid with measured multi-channel film dose maps. Results from two pilot audits are presented, using Ir-192 and Co-60 HDR sources, with a mean gamma passing rate of 98.6% using criteria of 3% local normalization and 3 mm distance to agreement (DTA). The mean DTA between prescribed dose and measured film dose at point A was 1.2 mm. The phantom was funded by IPEM and will be used for a UK national brachytherapy dosimetry audit.

  1. Design and implementation of a film dosimetry audit tool for comparison of planned and delivered dose distributions in high dose rate (HDR) brachytherapy

    International Nuclear Information System (INIS)

    Palmer, Antony L; Bradley, David; Nisbet, Andrew; Lee, Chris; Ratcliffe, Ailsa J

    2013-01-01

    A novel phantom is presented for ‘full system’ dosimetric audit comparing planned and delivered dose distributions in HDR gynaecological brachytherapy, using clinical treatment applicators. The brachytherapy applicator dosimetry test object consists of a near full-scatter water tank with applicator and film supports constructed of Solid Water, accommodating any typical cervix applicator. Film dosimeters are precisely held in four orthogonal planes bisecting the intrauterine tube, sampling dose distributions in the high risk clinical target volume, points A and B, bladder, rectum and sigmoid. The applicator position is fixed prior to CT scanning and through treatment planning and irradiation. The CT data is acquired with the applicator in a near clinical orientation to include applicator reconstruction in the system test. Gamma analysis is used to compare treatment planning system exported RTDose grid with measured multi-channel film dose maps. Results from two pilot audits are presented, using Ir-192 and Co-60 HDR sources, with a mean gamma passing rate of 98.6% using criteria of 3% local normalization and 3 mm distance to agreement (DTA). The mean DTA between prescribed dose and measured film dose at point A was 1.2 mm. The phantom was funded by IPEM and will be used for a UK national brachytherapy dosimetry audit. (paper)

  2. Thalassaemic osteoarthropathy treated with radiotherapy

    International Nuclear Information System (INIS)

    Davies, A.N.

    1993-01-01

    Patients with beta thalassaemia may develop a specific osteoarthropathy involving the feet. A number of different treatments for this condition have been tried, including rest, analgesia and hypertransfusion. We report a case of a patient with thalassaemic osteoarthropathy who responded to radiotherapy after failing conventional treatment. (author)

  3. Costing in Radiotherapy. Chapter 18

    International Nuclear Information System (INIS)

    Zubizarreta, E.; Lievens, Y.; Levin, V.C.; Van Der Merwe, D.

    2017-01-01

    The available literature on the cost of radiotherapy yields a large variation in data related to the specifics of the methodology used (the viewpoint of the analysis, time frame, health care system, etc.) and to the cost components and radiotherapy activities included. To overcome this difficulty, the reimbursement paid by medical insurance is commonly used as a proxy for the actual radiotherapy costs. Costs, however, generally bear little or no resemblance to charges, as the latter also include allowances for non-capacity use and profit margins. Accurate resource cost data are therefore more valid and should ideally be used in the context of economic evaluations and public health provisions. In addition to the theoretical problems related to obtaining accurate costs, it is difficult to interpret cost data across country borders because of differences in economics. If this is already the case for high income countries, using these cost data for low and middle income countries (LMICs) is even more problematic. Thus, there clearly is a need for calculations performed from the viewpoint of LMICs to prevent misapprehensions based on conclusions derived from data from their high income counterparts. The IAEA endeavours to assist Member States in accumulating appropriate and sufficient cost data for the initiation or expansion of radiation oncology services. Although relatively simple and easy to understand, the IAEA has found that in many countries where it has been involved in the establishment of new radiotherapy departments, the basic principles of cost calculation for radiotherapy facilities were not followed by the local planners. Radiotherapy needs careful planning, organization and a strong quality assurance (QA) programme in order to deliver safe treatments, due to the complexity of the planning and treatment process and the possibility of systematic errors. Administrators should be aware that the cost of building a radiotherapy facility and buying machines

  4. 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

  5. Anatomy-based inverse planning dose optimization in HDR prostate implant: A toxicity study

    International Nuclear Information System (INIS)

    Mahmoudieh, Alireza; Tremblay, Christine; Beaulieu, Luc; Lachance, Bernard; Harel, Francois; Lessard, Etienne; Pouliot, Jean; Vigneault, Eric

    2005-01-01

    Background and purpose: The aim of this study is to evaluate the acute and late complications in patients who have received HDR implant boost using inverse planning, and to determine dose volume correlations. Patients and methods: Between September 1999 and October 2002, 44 patients with locally advanced prostate cancer (PSA ≥10 ng/ml, and/or Gleason score ≥7, and/or Stage T2c or higher) were treated with 40-45 Gy external pelvic field followed by 2-3 fraction of inverse-planned HDR implant boost (6-9.5 Gy /fraction). Median follow-up time was 1.7 years with 81.8% of patients who had at least 12 months of follow up (range 8.6-42.5. Acute and late morbidity data were collected and graded according to RTOG criteria. Questionnaires were used to collect prostate related measures of quality of life, and international prostate symptom score (IPSS) before and after treatment. Dose-volume histograms for prostate, urethra, bladder, penis bulb and rectum were analyzed. Results: The median patient age was 64 years. Of these, 32% were in the high risk group, and 61% in the intermediate risk group. 3 patients (7%) had no adverse prognostic factors. A single grade 3 GU acute toxicity was reported but no grade 3-4 acute GI toxicity. No grade 3-4 late GU or GI toxicity was reported. Acute (late) grade 2 urinary and rectal symptoms were reported in 31.8 (11.4%) and 4.6% (4.6%) of patients, respectively. A trend for predicting acute GU toxicity is seen for total HDR dose of more than 18 Gy (OR=3.6, 95%CI=[0.96-13.5], P=0.058). The evolution of toxicity is presented for acute and late GU/GI toxicity. Erectile dysfunction occurs in approximately 27% of patients who were not on hormonal deprivation, but may be taking sildenafil. The IPSS peaked on averaged 6 weeks post-implant and returned to the baseline at a median of 6 months. Conclusions: Inverse-planned HDR brachytherapy is a viable option to deliver higher dose to the prostate as a boost without increasing GU or rectal

  6. Developing A Directional High-Dose Rate (d-HDR) Brachytherapy Source

    Science.gov (United States)

    Heredia, Athena Yvonne

    Conventional sources used in brachytherapy provide nearly isotropic or radially symmetric dose distributions. Optimizations of dose distributions have been limited to varied dwell times at specified locations within a given treatment volume, or manipulations in source position for seed implantation techniques. In years past, intensity modulated brachytherapy (IMBT) has been used to reduce the amount of radiation to surrounding sensitive structures in select intracavitary cases by adding space or partial shields. Previous work done by Lin et al., at the University of Wisconsin-Madison, has shown potential improvements in conformality for brachytherapy treatments using a directionally shielded low dose rate (LDR) source for treatments in breast and prostate. Directional brachytherapy sources irradiate approximately half of the radial angles around the source, and adequately shield a quarter of the radial angles on the opposite side, with sharp gradient zones between the treated half and shielded quarter. With internally shielded sources, the radiation can be preferentially emitted in such a way as to reduce toxicities in surrounding critical organs. The objective of this work is to present findings obtained in the development of a new directional high dose rate (d-HDR) source. To this goal, 103Pd (Z = 46) is reintroduced as a potential radionuclide for use in HDR brachytherapy. 103Pd has a low average photon energy (21 keV) and relatively short half -life (17 days), which is why it has historically been used in low dose rate applications and implantation techniques. Pd-103 has a carrier-free specific activity of 75000 Ci/g. Using cyclotron produced 103Pd, near carrier-free specific activities can be achieved, providing suitability for high dose rate applications. The evolution of the d-HDR source using Monte Carlo simulations is presented, along with dosimetric parameters used to fully characterize the source. In addition, a discussion on how to obtain elemental

  7. Clinical quality standards for radiotherapy

    Science.gov (United States)

    2012-01-01

    Aim of the study The technological progress that is currently being witnessed in the areas of diagnostic imaging, treatment planning systems and therapeutic equipment has caused radiotherapy to become a high-tech and interdisciplinary domain involving staff of various backgrounds. This allows steady improvement in therapy results, but at the same time makes the diagnostic, imaging and therapeutic processes more complex and complicated, requiring every stage of those processes to be planned, organized, controlled and improved so as to assure high quality of services provided. The aim of this paper is to present clinical quality standards for radiotherapy as developed by the author. Material and methods In order to develop the quality standards, a comparative analysis was performed between European and Polish legal acts adopted in the period of 1980-2006 and the universal industrial ISO 9001:2008 standard, defining requirements for quality management systems, and relevant articles published in 1984-2009 were reviewed, including applicable guidelines and recommendations of American, international, European and Polish bodies, such as the American Association of Physicists in Medicine (AAPM), the European Society for Radiotherapy & Oncology (ESTRO), the International Atomic Energy Agency (IAEA), and the Organisation of European Cancer Institutes (OECI) on quality assurance and management in radiotherapy. Results As a result, 352 quality standards for radiotherapy were developed and categorized into the following three groups: 1 – organizational standards; 2 – physico-technical standards and 3 – clinical standards. Conclusion Proposed clinical quality standards for radiotherapy can be used by any institution using ionizing radiation for medical purposes. However, standards are of value only if they are implemented, reviewed, audited and improved, and if there is a clear mechanism in place to monitor and address failure to meet agreed standards. PMID:23788854

  8. Historical aspects of heavy ion radiotherapy

    International Nuclear Information System (INIS)

    Raju, M.R.

    1995-01-01

    This paper presents historical developments of heavy-ion radiotherapy including discussion of HILAC and HIMAC and discussion of cooperation between Japan and the United States, along with personal reflections

  9. Stereotactic body radiotherapy a practical guide

    CERN Document Server

    Gaya, Andrew

    2015-01-01

    Collecting the key information in this burgeoning field into a single volume, this handbook for clinical oncology trainees and consultants covers all of the basic aspects of stereotactic radiotherapy systems and treatment and includes plenty of case studies.

  10. The effect on the radiotherapy for cervical cancer patients quality of life and the related health education

    International Nuclear Information System (INIS)

    Gao Xinli

    2012-01-01

    Radiotherapy is an important means of cervical cancer, due to the specificity of tumor site and side effect of radiotherapy, lack of knowledge of radiotherapy for patients and relatives about the disease, It is particularly important during radiotherapy on health education. By the analysis of radiotherapy for cervical cancer patients quality of life, it is the purpose of patients during the period of radiotherapy of whole course health education. Including before radiotherapy, radiotherapy in health education and the guide of the leaving hospital. In order to improve the compliance of patients, reduce the complications. Further it is improved the clinical treatment effect. (author)

  11. Adjuvant radiotherapy for stage I endometrial cancer.

    Science.gov (United States)

    Kong, A; Johnson, N; Cornes, P; Simera, I; Collingwood, M; Williams, C; Kitchener, H

    2007-04-18

    The role of adjuvant radiotherapy (both pelvic external beam radiotherapy and vaginal intracavity brachytherapy) in stage I endometrial cancer following total abdominal hysterectomy and bilateral salpingo-oophorectomy (TAH and BSO) remains unclear. To assess the efficacy of adjuvant radiotherapy following surgery for stage I endometrial cancer. The Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, CancerLit, Physician Data Query (PDQ) of National Cancer Institute. Handsearching was also carried out where appropriate. Randomised controlled trials (RCTs) which compared adjuvant radiotherapy versus no radiotherapy following surgery for patients with stage I endometrial cancer were included. Quality of the studies was assessed and data collected using a predefined data collection form. The primary endpoint was overall survival. Secondary endpoints were locoregional recurrence, distant recurrence and endometrial cancer death. Data on quality of life (QOL) and morbidity were also collected. A meta-analysis on included trials was performed using the Cochrane Collaboration Review Manager Software 4.2. The meta-analysis was performed on four trials (1770 patients). The addition of pelvic external beam radiotherapy to surgery reduced locoregional recurrence, a relative risk (RR) of 0.28 (95% confidence interval (CI) 0.17 to 0.44, p ASTEC; Lukka) are awaited. External beam radiotherapy carries a risk of toxicity and should be avoided in stage 1 endometrial cancer patients with no high risk factors.

  12. Arterial occlusive disease after radiotherapy

    International Nuclear Information System (INIS)

    Piedbois, P.; Mazeron, J.J.; Le Bourgeois, J.P.; Becquemin, J.P.; Blanc, I.; Lange, F.; Melliere, D.

    1990-01-01

    Fourteen cases of arterial occlusion or severe narrowing following radiotherapy are studied in order to assess the possible etiological role of such therapy in arterial lesion. Surgical results are also discussed in terms of long-term efficacy. The average time of occurrence after radiotherapy was 8 years post-radiotherapy. This series includes 7 supra-aortic trunk stenoses and 7 abdominal aorta trunk stenoses. The doses received in the volumes iradiated ranged from 47 to 70 Gy with standard fractionation. Association of atherosclerotic risk factors was present in 12 patients, but stenoses were usually confined to irradiated areas, and at imes occurred in uncommon sites. Surgical management included 11 by-passes, 2 endarterectomies and one percutaneous transluminal angioplasty. All patients experienced immediate and satisfactory functional improvements. Three patients were re-operated on because of the re-occlusion of the by-pass and graft infection. On the whole, stenoses in previously irradiated areas showed no particular difficulties for surgical treatment. It was concluded that radiotherapy seems to be a definite risk factor for arterial occlusion or narrowing, especially in association in association with atherosclerotic risk factors. (author). 45 refs.; 3 figs.; 2 tabs

  13. 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

  14. WE-AB-207B-11: Optimizing Tumor Control Probability in Radiation Therapy Treatment - Application to HDR Cervical Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Lee, E [Georgia Institute of Technology, Atlanta, GA (Georgia); Yuan, F [Georgia Institute of Technology, Atlanta, GEORGIA (United States); Templeton, A [Rush University Medical Center, Chicago, IL (United States); Yao, R [Columbus Regional Healthcare, Columbus, GA (United States); Chu, J [Rush University Medical Center, Oak Brook, IL (United States)

    2016-06-15

    Purpose: The ultimate goal of radiotherapy treatment planning is to find a treatment that will yield a high tumor-control-probability(TCP) with an acceptable normal-tissue-complication probability(NTCP). Yet most treatment planning today is not based upon optimization of TCPs and NTCPs, but rather upon meeting physical dose and volume constraints defined by the planner. We design treatment plans that optimize TCP directly and contrast them with the clinical dose-based plans. PET image is incorporated to evaluate gain in TCP for dose escalation. Methods: We build a nonlinear mixed integer programming optimization model that maximizes TCP directly while satisfying the dose requirements on the targeted organ and healthy tissues. The solution strategy first fits the TCP function with a piecewise-linear approximation, then solves the problem that maximizes the piecewise linear approximation of TCP, and finally performs a local neighborhood search to improve the TCP value. To gauge the feasibility, characteristics, and potential benefit of PET-image guided dose escalation, initial validation consists of fifteen cervical cancer HDR patient cases. These patients have all received prior 45Gy of external radiation dose. For both escalated strategies, we consider 35Gy PTV-dose, and two variations (37Gy-boost to BTV vs 40Gy-boost) to PET-image-pockets. Results: TCP for standard clinical plans range from 59.4% - 63.6%. TCP for dose-based PET-guided escalated-dose-plan ranges from 63.8%–98.6% for all patients; whereas TCP-optimized plans achieves over 91% for all patients. There is marginal difference in TCP among those with 37Gy-boosted vs 40Gy-boosted. There is no increase in rectum and bladder dose among all plans. Conclusion: Optimizing TCP directly results in highly conformed treatment plans. The TCP-optimized plan is individualized based on the biological PET-image of the patients. The TCP-optimization framework is generalizable and has been applied successfully to other

  15. WE-AB-207B-11: Optimizing Tumor Control Probability in Radiation Therapy Treatment - Application to HDR Cervical Cancer

    International Nuclear Information System (INIS)

    Lee, E; Yuan, F; Templeton, A; Yao, R; Chu, J

    2016-01-01

    Purpose: The ultimate goal of radiotherapy treatment planning is to find a treatment that will yield a high tumor-control-probability(TCP) with an acceptable normal-tissue-complication probability(NTCP). Yet most treatment planning today is not based upon optimization of TCPs and NTCPs, but rather upon meeting physical dose and volume constraints defined by the planner. We design treatment plans that optimize TCP directly and contrast them with the clinical dose-based plans. PET image is incorporated to evaluate gain in TCP for dose escalation. Methods: We build a nonlinear mixed integer programming optimization model that maximizes TCP directly while satisfying the dose requirements on the targeted organ and healthy tissues. The solution strategy first fits the TCP function with a piecewise-linear approximation, then solves the problem that maximizes the piecewise linear approximation of TCP, and finally performs a local neighborhood search to improve the TCP value. To gauge the feasibility, characteristics, and potential benefit of PET-image guided dose escalation, initial validation consists of fifteen cervical cancer HDR patient cases. These patients have all received prior 45Gy of external radiation dose. For both escalated strategies, we consider 35Gy PTV-dose, and two variations (37Gy-boost to BTV vs 40Gy-boost) to PET-image-pockets. Results: TCP for standard clinical plans range from 59.4% - 63.6%. TCP for dose-based PET-guided escalated-dose-plan ranges from 63.8%–98.6% for all patients; whereas TCP-optimized plans achieves over 91% for all patients. There is marginal difference in TCP among those with 37Gy-boosted vs 40Gy-boosted. There is no increase in rectum and bladder dose among all plans. Conclusion: Optimizing TCP directly results in highly conformed treatment plans. The TCP-optimized plan is individualized based on the biological PET-image of the patients. The TCP-optimization framework is generalizable and has been applied successfully to other

  16. Radiotherapy of bladder cancer

    International Nuclear Information System (INIS)

    Ikeda, Yoshiyuki

    1978-01-01

    Methods of treating bladder cancer include surgery, radiotherapy and chemotherapy, as well as various combinations of these. The author investigated clinically and histopathologically the therapeutic results of preoperative irradiation in cases of bladder cancer. 1. The survival rates (crude survival rates) in forty cases of bladder cancer were 90% after one year, 62.5% after three years and 46% after five years from the treatment. 2. As the result of irradiation, urogram improved in 25%, which was comparatively remarkable in high stage cases. There were no cases of deterioration of urogram findings caused by irradiation. Cystoscopy revealed disappearance or remarkable shrinkage of the tumors in 35% of the total cases and effects of the irradiation was observed not correlated to the stage and grade. 3. With respect to the histopathological changes, the changes became greater as the dosage increased and the higher the stage and grade were the more remarkable tendency was observed. 4. From our clinical observations such as urogram, cystoscopy and histopathologically, we estimated the optimum dosage of preoperative irradiation for bladder cancer is 3000 - 4000 rad. Thus, we concluded that the radiotherapy is effective in reducing both surgical invasion and postoperative recurrence. (author)

  17. A comparison of HDR brachytherapy and IMRT techniques for dose escalation in prostate cancer: A radiobiological modeling study

    Energy Technology Data Exchange (ETDEWEB)

    Fatyga, M.; Williamson, J. F.; Dogan, N.; Todor, D.; Siebers, J. V.; George, R.; Barani, I.; Hagan, M. [Department of Radiation Oncology, Virginia Commonwealth University Medical Center, 401 College Street, Richmond, Virginia 23298 (United States)

    2009-09-15

    A course of one to three large fractions of high dose rate (HDR) interstitial brachytherapy is an attractive alternative to intensity modulated radiation therapy (IMRT) for delivering boost doses to the prostate in combination with additional external beam irradiation for intermediate risk disease. The purpose of this work is to quantitatively compare single-fraction HDR boosts to biologically equivalent fractionated IMRT boosts, assuming idealized image guided delivery (igIMRT) and conventional delivery (cIMRT). For nine prostate patients, both seven-field IMRT and HDR boosts were planned. The linear-quadratic model was used to compute biologically equivalent dose prescriptions. The cIMRT plan was evaluated as a static plan and with simulated random and setup errors. The authors conclude that HDR delivery produces a therapeutic ratio which is significantly better than the conventional IMRT and comparable to or better than the igIMRT delivery. For the HDR, the rectal gBEUD analysis is strongly influenced by high dose DVH tails. A saturation BED, beyond which no further injury can occur, must be assumed. Modeling of organ motion uncertainties yields mean outcomes similar to static plan outcomes.

  18. A novel GATA3 nonsense mutation in a newly diagnosed adult patient of hypoparathyroidism, deafness, and renal dysplasia (HDR) syndrome.

    Science.gov (United States)

    Nanba, Kazutaka; Usui, Takeshi; Nakamura, Michikazu; Toyota, Yuko; Hirota, Keisho; Tamanaha, Tamiko; Kawashima, Sachiko-Tsukamoto; Nakao, Kanako; Yuno, Akiko; Tagami, Tetsuya; Naruse, Mitsuhide; Shimatsu, Akira

    2013-01-01

    Hypoparathyroidism, deafness, and renal dysplasia (HDR) syndrome is an autosomal dominant disorder caused by a GATA3 gene mutation. Here we report a novel mutation of GATA3 in a patient diagnosed with HDR syndrome at the age of 58 with extensive intracranial calcification. A 58-year-old Japanese man showed severe hypocalcemia and marked calcification in the basal ganglia, cerebellum, deep white matter, and gray-white junction on computed tomography (CT). The serum intact parathyroid hormone level was relatively low against low serum calcium concentration. The patient had been diagnosed with bilateral sensorineural deafness in childhood and had a family history of hearing disorders. Imaging studies revealed no renal anomalies. The patient was diagnosed with HDR syndrome, and genetic testing was performed. Genetic analysis of GATA3 showed a novel nonsense mutation at codon 198 (S198X) in exon 3. The S198X mutation leads to a loss of two zinc finger deoxyribonucleic acid (DNA) binding domains and is considered to be responsible for HDR syndrome. We identified a novel nonsense mutation of GATA3 in an adult patient with HDR syndrome who showed extensive intracranial calcification.

  19. Imaging and concomitant dose in radiotherapy

    International Nuclear Information System (INIS)

    Negi, P.S.

    2008-01-01

    Image guidance in radiotherapy now involves multiple imaging procedures for planning, simulation, set-up inter and intrafraction monitoring. Presently ALARA (i.e. as low as reasonable achievable) is the principle of management of dose to radiation workers and patients in any diagnostic imaging procedures including image guided surgery. The situation is different in repeated radiographic/fluoroscopic imaging performed for simulation, dose planning, patient positioning and set-up corrections during preparation/execution of Image guided radiotherapy (IGRT) as well as for Intensity Modulated Radiotherapy (IMRT). Reported imaging and concomitant doses will be highlighted and discussed for the management and optimization of imaging techniques in IMRT and IGRT

  20. The metabolic radiotherapy. La radiotherapie metabolique

    Energy Technology Data Exchange (ETDEWEB)

    Begon, F.; Gaci, M. (Centre Hospitalier Universitaire, 86 - Poitiers (France))

    In this article, the authors recall the principles of the metabolic radiotherapy and present these main applications in the treatment of thyroid cancers, hyperthyroidism, polycythemia, arthritis, bone metastases, adrenergic neoplasms. They also present the radioimmunotherapy.

  1. Barriers to palliative radiotherapy referral: A Canadian perspective

    International Nuclear Information System (INIS)

    Samant, Rajiv S.; Fitzgibbon, Edward; Meng, Joanne; Graham, Ian D.

    2007-01-01

    Radiotherapy is an effective but underutilized treatment modality for cancer patients. We decided to investigate the factors influencing radiotherapy referral among family physicians in our region. A 30-item survey was developed to determine palliative radiotherapy knowledge and factors influencing referral. It was sent to 400 physicians in eastern Ontario (Canada) and the completed surveys were evaluated. The overall response rate was 50% with almost all physicians seeing cancer patients recently (97%) and the majority (80%) providing palliative care. Approximately 56% had referred patients for radiotherapy previously and 59% were aware of the regional community oncology program. Factors influencing radiotherapy referral included the following: waiting times for radiotherapy consultation and treatment, uncertainty about the benefits of radiotherapy, patient age, and perceived patient inconvenience. Physicians who referred patients for radiotherapy were more than likely to provide palliative care, work outside of urban centres, have hospital privileges and had sought advice from a radiation oncologist in the past. A variety of factors influence the referral of cancer patients for radiotherapy by family physicians and addressing issues such as long waiting times, lack of palliative radiotherapy knowledge and awareness of Cancer Centre services could increase the rate of appropriate radiotherapy patient referral

  2. Quality Audits In Radiotherapy. Chapter 20

    International Nuclear Information System (INIS)

    Izewska, J.

    2017-01-01

    It is widely recognized that quality audits constitute a vital component of quality management in radiotherapy [20.1–20.3]. The main reason why quality audits are considered an important activity is that they help to review the quality of radiotherapy services and improve them. Quality audits check whether radiotherapy practices are adequate, i.e. that what should be done is being done; and in case it is not, audits provide recommendations to encourage improvements to be made. Without some form of auditing, it would be difficult to determine whether radiotherapy services are safe and effective for cancer treatment. In other words, a quality audit in radiotherapy is a method of reviewing whether the quality of activities in a radiotherapy department adheres to the standards of good practices to ensure that the treatment to the cancer patient is optimal. Overall, audits lead to improvements of professional practices and the general quality of services delivered. There are many recommendations regarding quality in radiotherapy practice, both national and international. Practices vary depending on the economic level of States, including specific procedures, equipment and facilities, as well as available resources. Good practices evolve with research developments, including new clinical trial results, progress in evidence based medicine and developments in radiotherapy technology. Quality audits involve the process of fact finding and comparing the findings against criteria for good practices in radiotherapy. Various issues and gaps may be identified by the auditors in the audit process, for example insufficiencies in structure, inadequacies in technology or deviations in procedures. This way the weak points or areas of concern are documented and recommendations for the audited centre are formulated that address these areas with the purpose of improving quality.

  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.

    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.

  4. Hypofractionated radiotherapy for invasive bladder cancer

    International Nuclear Information System (INIS)

    Scholten, Astrid N.; Leer, Jan-Willem H.; Collins, C. David; Wondergem, Jan; Hermans, Jo; Timothy, Adrian

    1997-01-01

    Background and purpose: The policy of the Radiotherapy Department of St. Thomas' Hospital in London for patients with invasive bladder cancer, used to be treatment with hypofractionated radiotherapy. The advantages of this fractionation scheme included reduction of the number of treatment sessions and better use of limited resources. Our results after hypofractionation were compared to series with more conventional radiotherapy. Material and methods: Between 1975 and 1985, 123 patients with a T2-T3 transitional cell carcinoma of the bladder were treated by a radical course of hypofractionated radiotherapy. Local control, survival and morbidity rates were analysed retrospectively. Results: The actuarial local control rates at 5 and 10 years were 31 and 29%, respectively. The actuarial cancer-specific 5- and 10-year survival rates were 48 and 39%, respectively. Acute side effects were observed in 87% of patients. The actuarial overall and severe late complication rates at 5 years were 33 and 9%, respectively. The local control, survival and early side effect rates we found, were in the same range as those reported in literature. Late radiation side effects however, were more common after hypofractionated radiotherapy compared to conventional radiotherapy schedules. Conclusions: We conclude that the potential advantage of a reduced number of treatment sessions may be lost in the long term, because of the higher incidence of late morbidity after hypofractionated radiotherapy. Hypofractionation however, remains a valuable technique for palliation and deserves further investigation for radical treatment where access to equipment is difficult or resources are limited

  5. Palliative radiotherapy in developing countries

    International Nuclear Information System (INIS)

    Allen, B.J.

    2010-01-01

    Full text: The International Agency for Research on Cancer predicts that cancer incidence in developing countries will increase dramatically in the first two decades of this millennium. Already some 80% of cancer patients in developing countries present with incurable disease. [n many cases pain is a severe problem and palliation is needed to improve quality of life as well as extending survival. This paper will consider the physical and clinical aspects of palliative radiotherapy (PRT), choice of radiation modality, alternative approaches to imaging and therapy and cost-benefit considerations. The potential benefits of a dedicated palliative centre include lower cost and therefore more centres, enabling more patients access to regional palliative care. Whilst there is an obvious need for palliative radiotherapy, simple curative treatments could also be managed. C060 radiotherapy has important advantages in developing countries, because of the higher initial cost of a linear accelerator, as well as the need for reliable power supply and the level of skill required by linac technicians and physicists. The beam characteristics of both C060 units and low energy linacs are compared and both are found to be acceptable for palliation. The concept of telemedicine is also discussed, using mobile phones and internet communication to allow rural clinics to receive support from specialists based in the cities, to send images for remote diagnosis and remote dose planning for radiotherapy. (author)

  6. Stereotactic intracranial radiotherapy: Dose prescription

    International Nuclear Information System (INIS)

    Schlienger, M.; Lartigau, E.; Nataf, F.; Mornex, F.; Latorzeff, I.; Lisbona, A.; Mahe, M.

    2012-01-01

    The aim of this article was the study of the successive steps permitting the prescription of dose in stereotactic intracranial radiotherapy, which includes radiosurgery and fractionated stereotactic radiotherapy. The successive steps studied are: the choice of stereotactic intracranial radiotherapy among the therapeutic options, based on curative or palliative treatment intent, then the selection of lesions according to size/volume, pathological type and their number permitting the choice between radiosurgery or fractionated stereotactic radiotherapy, which have the same methodological basis. Clinical experience has determined the level of dose to treat the lesions and limit the irradiation of healthy adjacent tissues and organs at risk structures. The last step is the optimization of the different parameters to obtain a safe compromise between the lesion dose and healthy adjacent structures. Study of dose-volume histograms, coverage indices and 3D imaging permit the optimization of irradiation. For lesions close to or included in a critical area, the prescribed dose is planned using the inverse planing method. Implementation of the successively described steps is mandatory to insure the prescription of an optimized dose. The whole procedure is based on the delineation of the lesion and adjacent healthy tissues. There are sometimes difficulties to assess the delineation and the volume of the target, however improvement of local control rates and reduction of secondary effects are the proof that the totality of the successive procedures are progressively improved. In practice, stereotactic intracranial radiotherapy is a continually improved treatment method, which constantly benefits from improvements in the choice of indications, imaging, techniques of irradiation, planing/optimization methodology and irradiation technique and from data collected from prolonged follow-up. (authors)

  7. Response of HDR-VKL piping system to seismic test excitations: Comparison of analytical predictions and test measurements

    International Nuclear Information System (INIS)

    Srinivasan, M.G.; Kot, C.A.; Hsieh, B.J.

    1989-01-01

    As part of the earthquake investigations at the HDR (Heissdampfreaktor) Test Facility in Kahl/Main, FRG, simulated seismic tests (SHAM) were performed during April--May 1988 on the VKL (Versuchskreislauf) piping system. The purpose of these experiments was to study the behavior of piping subjected to a range of seismic excitation levels including those that exceed design levels manifold and that might induce failure of pipe supports or plasticity in the pipe runs, and to establish seismic margins for piping and pipe supports. Data obtained in the tests are also used to validate analysis methods. Detailed reports on the SHAM experiments are given elsewhere. The objective of this document is to evaluate a subsystem analysis module of the SMACS code. This module is a linear finite-element based program capable of calculating the response of nuclear power plant subsystems subjected to independent multiple-acceleration input excitation. The evaluation is based on a comparison of computational results of simulation of SHAM tests with corresponding test measurements

  8. Advances in radiotherapy

    International Nuclear Information System (INIS)

    Mackie, T.R.

    2005-01-01

    computer optimization to determine optimal beam delivery intensity maps in order to maximize the target coverage and spare critical tissues as much as possible. The intensity modulated beams are delivered by conventional multileaf collimators or binary collimators modulating fan beams delivered rotationally. IMRT can enable higher doses to be delivered to the tumor and/or reduce the complications of sensitive tissues. Variability in the setup of the patient and movement of organs has likely limited the success of radiation therapy in the past but has become critical with the newfound ability of IMRT to put high dose gradients between the tumor and critical tissues. These issues are now being addressed with imaging systems present in the treatment room. Image-guided radiation therapy (IGRT) includes methods, such as transabdominal ultrasound and in-room CT scanners to image the patient just before treatment to improve setup accuracy and methods such as electronic x-ray imaging systems viewing implanted markers during treatment to minimize the effect of organ motion. 18 Excluding proton radiotherapy, equipment costs of modern radiotherapy are only marginally greater than for conventional radiotherapy. In the developed world the cost of radiotherapy equipment is about 15-20% of the total to deliver the treatment. Moreover, the cost of radiation therapy delivery represents only about 10-15% of the budget of a comprehensive cancer center and so it is a bargain as compared to other therapy forms such as surgery and chemotherapy. (author)

  9. SU-E-T-149: Brachytherapy Patient Specific Quality Assurance for a HDR Vaginal Cylinder Case

    Energy Technology Data Exchange (ETDEWEB)

    Barbiere, J; Napoli, J; Ndlovu, A [Hackensack Univ Medical Center, Hackensack, NJ (United States)

    2015-06-15

    Purpose: Commonly Ir-192 HDR treatment planning system commissioning is only based on a single absolute measurement of source activity supplemented by tabulated parameters for multiple factors without independent verification that the planned distribution corresponds to the actual delivered dose. The purpose on this work is to present a methodology using Gafchromic film with a statistically valid calibration curve that can be used to validate clinical HDR vaginal cylinder cases by comparing the calculated plan dose distribution in a plane with the corresponding measured planar dose. Methods: A vaginal cylinder plan was created with Oncentra treatment planning system. The 3D dose matrix was exported to a Varian Eclipse work station for convenient extraction of a 2D coronal dose plane corresponding to the film position. The plan was delivered with a sheet of Gafchromic EBT3 film positioned 1mm from the catheter using an Ir-192 Nucletron HDR source. The film was then digitized with an Epson 10000 XL color scanner. Film analysis is performed with MatLab imaging toolbox. A density to dose calibration curve was created using TG43 formalism for a single dwell position exposure at over 100 points for statistical accuracy. The plan and measured film dose planes were registered using a known dwell position relative to four film marks. The plan delivered 500 cGy to points 2 cm from the sources. Results: The distance to agreement of the 500 cGy isodose between the plan and film measurement laterally was 0.5 mm but can be as much as 1.5 mm superior and inferior. The difference between the computed plan dose and film measurement was calculated per pixel. The greatest errors up to 50 cGy are near the apex. Conclusion: The methodology presented will be useful to implement more comprehensive quality assurance to verify patient-specific dose distributions.

  10. 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.

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

    International Nuclear Information System (INIS)

    Kolotas, C.; Roeddiger, S.; Martin, T.; Tselis, N.; Baltas, D.; Zamboglou, N.; Strassmann, G.; Aebersold, D.M.

    2003-01-01

    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 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 3 with a range of 41-2,103 cm 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.)

  12. 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.)

  13. Westinghouse-GOTHIC distributed parameter modelling for HDR test E11.2

    International Nuclear Information System (INIS)

    Narula, J.S.; Woodcock, J.

    1994-01-01

    The Westinghouse-GOTHIC (WGOTHIC) code is a sophisticated mathematical computer code designed specifically for the thermal hydraulic analysis of nuclear power plant containment and auxiliary buildings. The code is capable of sophisticated flow analysis via the solution of mass, momentum, and energy conservation equations. Westinghouse has investigated the use of subdivided noding to model the flow patterns of hydrogen following its release into a containment atmosphere. For the investigation, several simple models were constructed to represent a scale similar to the German HDR containment. The calculational models were simplified to test the basic capability of the plume modeling methods to predict stratification while minimizing the number of parameters. A large empty volume was modeled, with the same volume and height as HDR. A scenario was selected that would be expected to stably stratify, and the effects of noding on the prediction of stratification was studied. A single phase hot gas was injected into the volume at a height similar to that of HDR test E11.2, and there were no heat sinks modeled. Helium was released into the calculational models, and the resulting flow patterns were judged relative to the expected results. For each model, only the number of subdivisions within the containment volume was varied. The results of the investigation of noding schemes has provided evidence of the capability of subdivided (distributed parameter) noding. The results also showed that highly inaccurate flow patterns could be obtained by using an insufficient number of subdivided nodes. This presents a significant challenge to the containment analyst, who must weigh the benefits of increased noding with the penalties the noding may incur on computational efficiency. Clearly, however, an incorrect noding choice may yield erroneous results even if great care has been taken in modeling accurately all other characteristics of containments. (author). 9 refs., 9 figs

  14. 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.

  15. Radiotherapy in small countries.

    Science.gov (United States)

    Barton, Michael B; Zubizarreta, Eduardo H; Polo Rubio, J Alfredo

    2017-10-01

    To examine the availability of radiotherapy in small countries. A small country was defined as a country with a population less than one million persons. The economic status of each country was defined using the World Bank Classification. The number of cancers in each country was obtained from GLOBOCAN 2012. The number of cancer cases with an indication or radiotherapy was calculated using the CCORE model. There were 41 countries with a population of under 1 million; 15 were classified as High Income, 15 Upper Middle Income, 10 Lower Middle Income and one Low Income. 28 countries were islands. Populations ranged from 799 (Holy See) to 886450 (Fiji) and the total number of cancer cases occurring in small countries was 21,043 (range by country from 4 to 2476). Overall the total number of radiotherapy cases in small countries was 10982 (range by country from 2 to 1239). Radiotherapy was available in all HIC islands with 80 or more new cases of cancer in 2012 but was not available in any LMIC island. Fiji was the only LMIC island with a large radiotherapy caseload. Similar caseloads in non-island LMIC all had radiotherapy services. Most non-island HIC did not have radiotherapy services presumably because of the easy access to radiotherapy in neighbouring countries. There are no radiotherapy services in any LMIC islands. Copyright © 2017. Published by Elsevier Ltd.

  16. Is there any place for LDR brachytherapy for head and neck carcinomas in HDR era?

    Science.gov (United States)

    Fijuth, Jacek

    2009-03-01

    In Poland, the classical LDR brachytherapy for head and neck carcinomas with Ir-192 wires or hairpins has completely disappeared some time ago after 30 years of successful clinical use. Can this technique be fully and safely replaced by HDR or PDR application? This option seems attractive because of new possibilities of 3D reconstruction and computer real-time treatment planning and optimization. However, in my opinion, long time is needed to get a clinical and scientific experience that has been accumulated for decades with the use of LDR technique.

  17. 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...... other algorithms aim at enhancing contrast, with power savings as a side effect. In our earlier work, we have modeled backlight dimming as a linear programming problem, where the target is to minimize the cost function measuring the distance between ideal and actual output. In this paper, we propose...

  18. Prospective randomized trial of HDR brachytherapy as a sole modality in palliation of advanced esophageal carcinoma--an International Atomic Energy Agency study

    International Nuclear Information System (INIS)

    Sur, Ranjan K.; Levin, C. Victor; Donde, Bernard; Sharma, Vinay; Miszczyk, Leszek; Nag, Subir

    2002-01-01

    Background: Previous studies from South Africa have established that fractionated high-dose-rate (HDR) brachytherapy gives the best results in terms of palliation and survival in advanced esophageal cancer. A multicenter, prospective randomized study was therefore conducted under the auspices of the International Atomic Energy Agency to evaluate two HDR regimens. Methods and Materials: Surgically inoperable patients with histologically proven squamous cell cancer of the esophagus, tumor >5 cm in length on barium swallow and/or endoscopy, Karnofsky performance score >50, age 17-70 years, primary disease in the thoracic esophagus, no prior malignancy within the past 5 years, and any N or M status were included in the study. Exclusion criteria included cervical esophagus location, tumor extending 0.05). The overall survival was 7.9 months for the whole group (Group A, 9.1 months; Group B, 6.9 months; p>0.05). On univariate analysis, the presenting weight (p=0.0083), gender (p=0.0038), race (p=0.0105), the presenting dysphagia score (p=0.0083), the treatment center (p=0.0029), and tumor grade (p=0.0029) had an impact on the dysphagia-free survival, and gender (p=0.0011) and performance score (p=0.0060) had an impact on dysphagia-free survival on multivariate analysis. Only age had an impact on overall survival on both univariate (p=0.0430) and multivariate (p=0.0331) analysis. The incidence of strictures (Group A, n=12; Group B, n=13; p>0.05) and fistulas (Group A, n=11; Group B, n=12; p>0.05) was similar in both groups. Conclusion: Fractionated HDR brachytherapy alone is an effective method of palliating advanced esophageal cancers, surpassing the results of any other modality of treatment presently available. Dose fractions of 6 Gy x 3 and 8 Gy x 2 give similar results for dysphagia-free survival, overall survival, strictures, and fistulas and are equally effective in palliation of advanced esophageal cancer

  19. MO-C-17A-11: A Segmentation and Point Matching Enhanced Deformable Image Registration Method for Dose Accumulation Between HDR CT Images

    International Nuclear Information System (INIS)

    Zhen, X; Chen, H; Zhou, L; Yan, H; Jiang, S; Jia, X; Gu, X; Mell, L; Yashar, C; Cervino, L

    2014-01-01

    Purpose: To propose and validate a novel and accurate deformable image registration (DIR) scheme to facilitate dose accumulation among treatment fractions of high-dose-rate (HDR) gynecological brachytherapy. Method: We have developed a method to adapt DIR algorithms to gynecologic anatomies with HDR applicators by incorporating a segmentation step and a point-matching step into an existing DIR framework. In the segmentation step, random walks algorithm is used to accurately segment and remove the applicator region (AR) in the HDR CT image. A semi-automatic seed point generation approach is developed to obtain the incremented foreground and background point sets to feed the random walks algorithm. In the subsequent point-matching step, a feature-based thin-plate spline-robust point matching (TPS-RPM) algorithm is employed for AR surface point matching. With the resulting mapping, a DVF characteristic of the deformation between the two AR surfaces is generated by B-spline approximation, which serves as the initial DVF for the following Demons DIR between the two AR-free HDR CT images. Finally, the calculated DVF via Demons combined with the initial one serve as the final DVF to map doses between HDR fractions. Results: The segmentation and registration accuracy are quantitatively assessed by nine clinical HDR cases from three gynecological cancer patients. The quantitative results as well as the visual inspection of the DIR indicate that our proposed method can suppress the interference of the applicator with the DIR algorithm, and accurately register HDR CT images as well as deform and add interfractional HDR doses. Conclusions: We have developed a novel and robust DIR scheme that can perform registration between HDR gynecological CT images and yield accurate registration results. This new DIR scheme has potential for accurate interfractional HDR dose accumulation. This work is supported in part by the National Natural ScienceFoundation of China (no 30970866 and no

  20. External radiotherapy of pituitary adenomas

    International Nuclear Information System (INIS)

    Zierhut, Dietmar; Flentje, Michael; Adolph, Juergen; Erdmann, Johannes; Raue, Friedhelm; Wannenmacher, Michael

    1995-01-01

    Purpose: To evaluate therapeutic outcome and side effects of radiotherapy in pituitary adenomas as sole or combined treatment. Methods and Materials: Retrospective analysis of 138 patients (74 male, 64 female) irradiated for pituitary adenoma from 1972 to 1991 was performed. Mean age was 49.7 years (15-80 years). Regular follow-up (in the mean 6.53 ± 3.99 years) included radiodiagnostical [computed tomography (CT), magnetic resonance imaging (MRI), x-ray], endocrinological, and ophthalmological examinations. Seventy patients suffered from nonfunctional pituitary adenoma, 50 patients suffered from growth-hormone producing adenomas, 11 had prolactinomas, and 7 patients had adrenocorticotropic hormone (ACTH) producing pituitary adenomas. In 99 patients surgery was followed by radiotherapy in case of suspected remaining tumor (invasive growth of the adenoma, assessment of the surgeon, pathologic CT after surgery, persisting hormonal overproduction). Twenty-three patients were treated for recurrence of disease after surgery and 16 patients received radiation as primary treatment. Total doses from 40-60 Gy (mean: 45.5 Gy) were given with single doses of 2 Gy 4 to five times a week. Results: Tumor control was achieved in 131 patients (94.9%). In seven patients, recurrence of disease was diagnosed in the mean 2.9 years (9-98 months) after radiotherapy and salvaged by surgery. A statistically significant dose-response relationship was found in favor of doses ≥ 45 Gy. Ninety percent of the patients with hormonally active pituitary adenomas had a benefit from radiotherapy in means of complete termination (38%) or at least reduction (52%) of hormonal overproduction. Partial or complete hypopituitarism after radiotherapy developed, depending on hormonal axis, in 12 (prolactin) to 27% (follicle-stimulating hormone FSH) of patients who had not already had hypopituitarism prior to radiation. Two out of 138 patients suffered reduction of visual acuity, which was, in part

  1. Device for radiotherapy

    International Nuclear Information System (INIS)

    Levinta, A.

    2002-01-01

    The invention refers to medicine, in particular to radiology. Summary of the invention consists in that the device for the radiotherapy includes a base a headrest, a mechanism for head fixation, means for placement of the formation element, the mechanism for head fixation representing a semicircle situated in horizontal position and fixed to the base with the possibility of displacement, in the centre of which it is installed a fixing arm, and the means for placement of the formation elements representing at least two semicircles, mounted in vertical position and fixed into supports with the possibility of mutual swiveling of each of them, between the headrest and the base being installed the neck support

  2. Experimental work and know-how transfer in the framework of the individual project 'Earthquake investigations on the HDR reactor'

    International Nuclear Information System (INIS)

    Corvin, P.; Metz, K.

    1976-03-01

    In the framework of investigations to determine the earthquake resistance of nuclear power plant, carried out by the Applied Nucleonics Company on the HDR reactor in Grosswelzheim/Main, theoretical fundamentals and experimental test procedures in the sense of know-how transfer were elaborated. This enables the corresponding German institutions to carry out similar investigations on their own. In addition ANC carried out safety control measures during the investigations in order to prevent structural damage to the HDR reactor and neighbouring buildings. (orig.) 891 HP [de

  3. Evaluation of radiation doses on critical organs in the treatment of cancer of the cervix using HDR-brachytherapy

    International Nuclear Information System (INIS)

    Soares, Taciana; Jansem, Teresa

    2000-01-01

    High dose-rate (HDR) brachytherapy is one type of treatment of the cervix carcinoma. During the planning for this therapy, especial attention is given to proximal normal organs such as bladder and rectum. In fact, due to their radiosensibility and localization, bladder and rectum are considered as critical organs. In this work we have studied the influence of the positioning of patient legs in the dose delivered to these critical organs in the treatment of cancer of the cervix using HDR-brachytherapy. (author)

  4. Radiotherapy for Vestibular Schwannomas: A Critical Review

    International Nuclear Information System (INIS)

    Murphy, Erin S.; Suh, John H.

    2011-01-01

    Vestibular schwannomas are slow-growing tumors of the myelin-forming cells that cover cranial nerve VIII. The treatment options for patients with vestibular schwannoma include active observation, surgical management, and radiotherapy. However, the optimal treatment choice remains controversial. We have reviewed the available data and summarized the radiotherapeutic options, including single-session stereotactic radiosurgery, fractionated conventional radiotherapy, fractionated stereotactic radiotherapy, and proton beam therapy. The comparisons of the various radiotherapy modalities have been based on single-institution experiences, which have shown excellent tumor control rates of 91-100%. Both stereotactic radiosurgery and fractionated stereotactic radiotherapy have successfully improved cranial nerve V and VII preservation to >95%. The mixed data regarding the ideal hearing preservation therapy, inherent biases in patient selection, and differences in outcome analysis have made the comparison across radiotherapeutic modalities difficult. Early experience using proton therapy for vestibular schwannoma treatment demonstrated local control rates of 84-100% but disappointing hearing preservation rates of 33-42%. Efforts to improve radiotherapy delivery will focus on refined dosimetry with the goal of reducing the dose to the critical structures. As future randomized trials are unlikely, we suggest regimented pre- and post-treatment assessments, including validated evaluations of cranial nerves V, VII, and VIII, and quality of life assessments with long-term prospective follow-up. The results from such trials will enhance the understanding of therapy outcomes and improve our ability to inform patients.

  5. A method of quality audit for treatment planning system for intracavitary HDR brachytherapy

    International Nuclear Information System (INIS)

    Sharma, S.D.; Vandana, S.; Philomina, A.; Kannan, S.; Rituraj, U.

    2007-01-01

    High dose rate brachytherapy is a multipurpose modality. Quality audit (QAu) is an independent examination and evaluation of quality assurance activities and results of an institution. Both clinical and physical aspects of patient treatments must be subjected to careful control and planning to achieve a high degree of accuracy in radiation therapy treatments. Comprehensive quality assurance (QA) programmes should be established to cover all steps from dose prescription to dose delivery. These programmes should include detailed internal checks performed by the radiotherapy centres and external audits made by independent bodies. A systematic and independent examination and evaluation to determine whether quality activities and results comply with planned arrangements and whether the arrangements are implemented effectively and are suitable to achieve objectives is called quality audit. One purpose of a quality audit (QAu) is to evaluate the need for improvement or corrective action

  6. Anatomical imaging for radiotherapy

    International Nuclear Information System (INIS)

    Evans, Philip M

    2008-01-01

    scans is taken on different days. Both allow planning to account for variability intrinsic to the patient. Treatment verification has been carried out using a variety of technologies including: MV portal imaging, kV portal/fluoroscopy, MVCT, conebeam kVCT, ultrasound and optical surface imaging. The various methods have their pros and cons. The four x-ray methods involve an extra radiation dose to normal tissue. The portal methods may not generally be used to visualize soft tissue, consequently they are often used in conjunction with implanted fiducial markers. The two CT-based methods allow measurement of inter-fraction variation only. Ultrasound allows soft-tissue measurement with zero dose but requires skilled interpretation, and there is evidence of systematic differences between ultrasound and other data sources, perhaps due to the effects of the probe pressure. Optical imaging also involves zero dose but requires good correlation between the target and the external measurement and thus is often used in conjunction with an x-ray method. The use of anatomical imaging in radiotherapy allows treatment uncertainties to be determined. These include errors between the mean position at treatment and that at planning (the systematic error) and the day-to-day variation in treatment set-up (the random error). Positional variations may also be categorized in terms of inter- and intra-fraction errors. Various empirical treatment margin formulae and intervention approaches exist to determine the optimum strategies for treatment in the presence of these known errors. Other methods exist to try to minimize error margins drastically including the currently available breath-hold techniques and the tracking methods which are largely in development. This paper will review anatomical imaging techniques in radiotherapy and how they are used to boost the therapeutic benefit of the treatment. (topical review)

  7. Intensity modulated radiotherapy (IMRT) in bilateral retinoblastoma

    International Nuclear Information System (INIS)

    Atalar, Banu; Ozyar, Enis; Gunduz, Kaan; Gungor, Gorkem

    2010-01-01

    External beam radiotherapy (EBRT) for retinoblastoma has traditionally been done with conventional radiotherapy techniques which resulted high doses to the surrounding normal tissues. A 20 month-old girl with group D bilateral retinoblastoma underwent intensity modulated radiotherapy (IMRT) to both eyes after failing chemoreduction and focal therapies including cryotherapy and transpupillary thermotherapy. In this report, we discuss the use of IMRT as a method for reducing doses to adjacent normal tissues while delivering therapeutic doses to the tumour tissues compared with 3-dimensional conformal radiotherapy (3DCRT). At one year follow-up, the patient remained free of any obvious radiation complications. Image guided IMRT provides better dose distribution than 3DCRT in retinoblastoma eyes, delivering the therapeutic dose to the tumours and minimizing adjacent tissue damage

  8. PLANNING NATIONAL RADIOTHERAPY SERVICES

    Directory of Open Access Journals (Sweden)

    Eduardo eRosenblatt

    2014-11-01

    Full Text Available Countries, states and island nations often need forward planning of their radiotherapy services driven by different motives. Countries without radiotherapy services sponsor patients to receive radiotherapy abroad. They often engage professionals for a feasibility study in order to establish whether it would be more cost-beneficial to establish a radiotherapy facility. Countries where radiotherapy services have developed without any central planning, find themselves in situations where many of the available centres are private and thus inaccessible for a majority of patients with limited resources. Government may decide to plan ahead when a significant exodus of cancer patients travel to another country for treatment, thus exposing the failure of the country to provide this medical service for its citizens. In developed countries the trigger has been the existence of highly visible waiting lists for radiotherapy revealing a shortage of radiotherapy equipment.This paper suggests that there should be a systematic and comprehensive process of long-term planning of radiotherapy services at the national level, taking into account the regulatory infrastructure for radiation protection, planning of centres, equipment, staff, education pr

  9. Role of bio-effect models in improving radiotherapy of cancer

    International Nuclear Information System (INIS)

    Rao, B.S.

    2013-01-01

    Application of linear quadratic model of cell survival in radiotherapy has enabled to successfully predict the response of both the normal tissues and tumours. Even the simplest form of BED (biological effective dose) equation for fractionated radiotherapy could precisely predict the late normal tissue complications resulting from large dose per fraction. These observations have led to the development MFD (multiple fractions daily) protocol, with the specific objective of reducing late normal tissue morbidity. Protraction of treatment and consequent loss of BED and tumour control; multiple fractions delivered without adequate intervals resulting in incomplete repair of sub-lethal damage and consequent normal tissue complications, have been explained successfully by the LQ model. In the recent past LDR (low dose rate) brachytherapy is mostly replaced by HDR (high dose rate) technique. A series of calculations based on tumour bio-kinetics parameters, as well as the geometric sparing provides a sound rationale for replacing LDR technique by HDR technique. Some of the calculations relevant to this will be presented during this talk. Bio-effect models can also provide insight in to the rationale of RIT (radio-immunotherapy). With an adequate knowledge of biological half-life of antibodies in the tumour/critical organs, and biological uptake half-time in the tumour, it is possible to evaluate the efficacy of a number of radio-nuclides in RIT. Calculations based on LQ models suggest that longer lived isotopes such as 32 P, 86 Rb, 144m In may have an advantage over the shorter lived radio-nuclides. A clear knowledge of the various parameters like/values, potentially doubling time of tumour and other bio-kinetic parameters may hold the key for successful application of bio-effect models in predicting the response to radiotherapy. Feedback from the clinics will further help in refining and validating the existing models. (author)

  10. Radiotherapy gel dosimetry

    International Nuclear Information System (INIS)

    Baldock, C.

    2002-01-01

    be either through direct absorption of ionising radiation or via intermediate water free radicals. Fe 2+ ions are converted to Fe 3+ ions with a corresponding change in paramagnetic properties that may be quantified using NMR relaxation measurements or optical techniques. Due to predominantly diffusion-related limitations (and references therein), alternative polymer gel dosimeters were subsequently suggested. In polymer gels, monomers such as acrylamide and N,N'-methylene-bis-acrylamide are usually dispersed in a gelatin or agarose matrix. Monomers undergo a polymerisation reaction as a function of absorbed dose resulting in a 3D polymer gel matrix. The radiation-induced formation of polymer influences NMR relaxation properties and results in other physical changes that may be used to quantify absorbed radiation dose. As well as MRI, other quantitative techniques for measuring dose distributions include X-ray computer tomography, vibrational spectroscopy and ultrasound. Clinical applications of these radiologically tissue equivalent gel dosimeters have been reported in the literature. For further information of gel dosimetry and specifically clinical applications the proceedings of the 2nd International Conference on Radiotherapy Gel Dosimetry and references therein should be consulted

  11. Verification of experimental modal modeling using HDR (Heissdampfreaktor) dynamic test data

    International Nuclear Information System (INIS)

    Srinivasan, M.G.; Kot, C.A.; Hsieh, B.J.

    1983-01-01

    Experimental modal modeling involves the determination of the modal parameters of the model of a structure from recorded input-output data from dynamic tests. Though commercial modal analysis algorithms are being widely used in many industries their ability to identify a set of reliable modal parameters of an as-built nuclear power plant structure has not been systematically verified. This paper describes the effort to verify MODAL-PLUS, a widely used modal analysis code, using recorded data from the dynamic tests performed on the reactor building of the Heissdampfreaktor, situated near Frankfurt, Federal Republic of Germany. In the series of dynamic tests on HDR in 1979, the reactor building was subjected to forced vibrations from different types and levels of dynamic excitations. Two sets of HDR containment building input-output data were chosen for MODAL-PLUS analyses. To reduce the influence of nonlinear behavior on the results, these sets were chosen so that the levels of excitation are relatively low and about the same in the two sets. The attempted verification was only partially successful in that only one modal model, with a limited range of validity, could be synthesized and in that the goodness of fit could be verified only in this limited range

  12. Seismic tests at the HDR facility using explosives and solid propellant rockets

    International Nuclear Information System (INIS)

    Corvin, P.; Steinhilber, H.

    1981-01-01

    In blast tests the HDR reactor building and its mechanical equipment were subjected to earthquake-type excitations through the soil and the foundation. A series of six tests was carried out, two tests being made with HDR facility under operating conditions (BWR conditions, 285 0 C, 70 bar). The charges were placed in boreholes at a depth of 4 to 10 m and a distance of 16 to 25 m from the reactor building. The tests with solid propellant rockets were made in order to try a new excitation technique. The rockets used in these tests were of compact design and had a short combustion period (500 ms) at high constant thrust (100 kN per combustion chamber). These rockets were fixed to the concrete dome of the building in such a way that the thrust generated during the combustion of the propellant resulted in an impulsive load acting on the building. This type of excitation was selected with a view to investigating the global effects of the load case 'aircraft impact' on the building and the mechanical equipment. In the four tests made so far, up to four rockets were ignited simultaneously, so that the maximum impulse was 2 x 10 5 Ns. The excitation level can be markedly increased by adding further rockets. This excitation technique was characterised by excellent reproducibility of the load parameters. (orig./HP)

  13. Variability of Marker-Based Rectal Dose Evaluation in HDR Cervical Brachytherapy

    International Nuclear Information System (INIS)

    Wang Zhou; Jaggernauth, Wainwright; Malhotra, Harish K.; Podgorsak, Matthew B.

    2010-01-01

    In film-based intracavitary brachytherapy for cervical cancer, position of the rectal markers may not accurately represent the anterior rectal wall. This study was aimed at analyzing the variability of rectal dose estimation as a result of interfractional variation of marker placement. A cohort of five patients treated with multiple-fraction tandem and ovoid high-dose-rate (HDR) brachytherapy was studied. The cervical os point and the orientation of the applicators were matched among all fractional plans for each patient. Rectal points obtained from all fractions were then input into each clinical treated plan. New fractional rectal doses were obtained and a new cumulative rectal dose for each patient was calculated. The maximum interfractional variation of distances between rectal dose points and the closest source positions was 1.1 cm. The corresponding maximum variability of fractional rectal dose was 65.5%. The percentage difference in cumulative rectal dose estimation for each patient was 5.4%, 19.6%, 34.6%, 23.4%, and 13.9%, respectively. In conclusion, care should be taken when using rectal markers as reference points for estimating rectal dose in HDR cervical brachytherapy. The best estimate of true rectal dose for each fraction should be determined by the most anterior point among all fractions.

  14. 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.

  15. Adenocarcinoma of the stomach following radical radiotherapy for testicular cancer

    International Nuclear Information System (INIS)

    Griffith, C.D.M.; Chadderton, R.; Bourke, J.B.

    1990-01-01

    Two male patients who underwent curative surgery and adjuvant radiotherapy (with further chemotherapy in one) for testicular cancer developed adenocarcinoma of the stomach 5 and 19 years after treatment. The stomach is included in the field of radiotherapy used to treat the para-aortic lymph nodes and this may lead to dysplastic changes in the stomach mucosa which can lead to frank malignancy. Early endoscopy should be offered to patients with dyspeptic symptoms after adjuvant radiotherapy for testicular cancer. (author)

  16. To understand radiotherapy

    International Nuclear Information System (INIS)

    2009-01-01

    Dealing with the use of radiotherapy for adults, this guide indicates when a radiotherapy is suggested, how it acts, how the treatment is chosen, which are the professionals involved. It describes how an external radiotherapy takes place and its various techniques, the different types of side effects (general, specific to the treated zone, late effects). It indicates which organs can be treated by curie-therapy, the different curie-therapy treatment modalities, how a curie-therapy takes place and which are its side effects. It outlines how to better cope with radiotherapy (how to be supported, the important role of relatives, everyday life questions, rights). It indicates and comments the different measures adopted for the safety and quality of radiotherapy

  17. 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)

  18. 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

  19. Neutron radiotherapy

    International Nuclear Information System (INIS)

    Thomas, F.J.

    1987-01-01

    The rationale for the application of neutron radiation for the treatment of malignancies is well established based on radiobiological studies. These factors include the presence of tissue hypoxia, radiation response as a function of cell cycle kinetics, the repair capacity of the malignant cells and the regeneration of malignant cells during a fractionated course of radiation. Despite the constraints under which the clinical trials to date have been conducted, promising results have been obtained. Randomized trials have demonstrated that neutron therapy is the treatment of choice for inoperable salivary gland carcinomas. A randomized trial of the RTOG has demonstrated a probable advantage for neutron radiation in the treatment of advanced prostate carcinomas but is yet to be confirmed. An improvement in local control has also been observed for selected sarcomas. Equivocal or contradictory results have been obtained for squamous cell carcinomas of the head and neck, bronchogenic carcinomas, advanced rectal, transitional cell carcinomas of the bladder and cervical carcinomas. The practical consequences of these radiobiological and clinical observations on the current generation of clinical trials is discussed

  20. Pre- and post-calculations for crack opening and leak rate experiments on piping components within the HDR-program

    International Nuclear Information System (INIS)

    Grebner, H.; Hoefler, A.; Hunger, H.

    1991-01-01

    In this paper calculations to experiments on leak opening and leak rates of piping components are presented. The experiments are performed at the HDR-facility at Karlstein/Germany and up to now straight pipes and pipe branches were considered. Numerical and experimental results are compared. (author)

  1. Telemedicine in radiotherapy treatment planning: requirements and applications

    International Nuclear Information System (INIS)

    Olsen, D.R.; Bruland, O.S.; Davis, B.J.

    2000-01-01

    Telemedicine facilitates decentralized radiotherapy services by allowing remote treatment planning and quality assurance of treatment delivery. A prerequisite is digital storage of relevant data and an efficient and reliable telecommunication system between satellite units and the main radiotherapy clinic. The requirements of a telemedicine system in radiotherapy is influenced by the level of support needed. In this paper we differentiate between three categories of telemedicine support in radiotherapy. Level 1 features video conferencing and display of radiotherapy images and dose plans. Level 2 involves replication of selected data from the radiotherapy database - facilitating remote treatment planning and evaluation. Level 3 includes real-time, remote operations, e.g. target volume delineation and treatment planning performed by the team at the satellite unit under supervision and guidance from more experienced colleagues at the main clinic. (author)

  2. The result of radiotherapy for pituitary adenoma

    International Nuclear Information System (INIS)

    Lee, H. J.; Yang, K. M.; Suh, S. H.

    1997-01-01

    To evaluate the prognostic factors for disease-free survival and long-term results of radiotherapy for pituitary adenoma. The study involved a retrospective review of outcome in a series of 27 patients with pituitary adenoma, between 1984 and 1995 at Paik hospital. The study included 20 patients treated with surgery and postoperative radiotherapy and 7 with radiotherapy alone. The patients were followed for 12-146 months (median: 97 months). Seventeen were men and 10 were women. The numbers of functioning and non-functioning pituitary adenoma were 22 and 5 respectively and those of microadenoma and macroadenoma were 4 and 23 respectively. The radiation doses of 5040-5580cGy(median: 5040cGy) were delivered over 5-7 weeks, using 4MV LINAC. The prognostic factors were analyzed by log-rank test. For radiation therapy alone, the 5 YSR was 100% and progression free survival rate was 85.8%. The tumor was controlled in 6/7 (85.8%). For surgery and postoperative radiotherapy , the 5YSR, progression free survival rate and local control rate were 95%, 84.8%, and 89.5% respectively. The parameters of tumor size, hormone secretion, radiation dose, radiotherapy field size were evaluated in a uni- and multivariate analysis and all the factors were not statistically significant (P>0.05). Eleven of 12 (92%) with visual field defect experienced normalization or improvement, and 5 for 7 evaluable patients with hyperprolactinoma achieved normalization in 4 and decrement in 5 patients. Only 2 patients developed mild degree of panhypopituitarism. The radiotherapy appears to be effective in controlling clinical symptoms and signs resulting from pituitary adenoma. Local control rate with radiotherapy alone or with surgery and postoperative radiotherapy was comparable. There was a trend toward high recurrence rate in patients with nonfunctioning or prolactin secreting tumor and larger radiation field sizes. (author)

  3. The result of radiotherapy for pituitary adenoma

    Energy Technology Data Exchange (ETDEWEB)

    Lee, H. J.; Yang, K. M.; Suh, S. H. [Inje Univ., Seoul (Korea, Republic of). Coll. of Medicine; Cho, H. L.; Shon, S. C. [Pusan Paik Hospital, Pusan (Korea, Republic of)

    1997-12-01

    To evaluate the prognostic factors for disease-free survival and long-term results of radiotherapy for pituitary adenoma. The study involved a retrospective review of outcome in a series of 27 patients with pituitary adenoma, between 1984 and 1995 at Paik hospital. The study included 20 patients treated with surgery and postoperative radiotherapy and 7 with radiotherapy alone. The patients were followed for 12-146 months (median: 97 months). Seventeen were men and 10 were women. The numbers of functioning and non-functioning pituitary adenoma were 22 and 5 respectively and those of microadenoma and macroadenoma were 4 and 23 respectively. The radiation doses of 5040-5580cGy(median: 5040cGy) were delivered over 5-7 weeks, using 4MV LINAC. The prognostic factors were analyzed by log-rank test. For radiation therapy alone, the 5 YSR was 100% and progression free survival rate was 85.8%. The tumor was controlled in 6/7 (85.8%). For surgery and postoperative radiotherapy , the 5YSR, progression free survival rate and local control rate were 95%, 84.8%, and 89.5% respectively. The parameters of tumor size, hormone secretion, radiation dose, radiotherapy field size were evaluated in a uni- and multivariate analysis and all the factors were not statistically significant (P>0.05). Eleven of 12 (92%) with visual field defect experienced normalization or improvement, and 5 for 7 evaluable patients with hyperprolactinoma achieved normalization in 4 and decrement in 5 patients. Only 2 patients developed mild degree of panhypopituitarism. The radiotherapy appears to be effective in controlling clinical symptoms and signs resulting from pituitary adenoma. Local control rate with radiotherapy alone or with surgery and postoperative radiotherapy was comparable. There was a trend toward high recurrence rate in patients with nonfunctioning or prolactin secreting tumor and larger radiation field sizes. (author).

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

    International Nuclear Information System (INIS)

    Kertzscher, Gustavo; Andersen, Claus E.; Siebert, Frank-Andre; Nielsen, Soren Kynde; Lindegaard, Jacob C.; Tanderup, Kari

    2011-01-01

    Background and purpose: 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. Materials and methods: 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 2-20 mm 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 1-4 mm). Results: 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 10 mm dosimeter displacement errors unidentified. Dwell position dose rate comparisons correctly identified displacements ≥5 mm. Conclusion: This phantom study demonstrates that Al 2 O 3 :C real-time dosimetry can identify applicator displacements ≥5 mm 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.

  5. Experimental radiotherapy and clinical radiobiology. Vol. 20. Proceedings

    International Nuclear Information System (INIS)

    Baumann, Michael; Dahm-Daphi, Jochen; Dikomey, Ekkehard; Petersen, Cordula; Rodemannn, Hans-Peter; Zips, Daniel

    2011-01-01

    The proceedings include contributions on the following issues: laser driven proton accelerators on the way for radiotherapy, radiobiological evaluation of new radiations; molecular factors of radiation response; biological targeting; EGFR epidermal growth factor receptor/targeting - combined internal and external irradiation, radiobiology of normal tissues; dose-volume histograms for the radiotherapy: curves without radiobiological relevance or important information for the therapy planning; HPV (human papilloma virus) and radiation sensitivity of HNSCC (head and neck squamous cell carcinomas): evidence, radiobiological mechanism, clinical consequences and perspectives; mechanisms of action and intertumoral heterogeneity of response to EGFR inhibition in radiotherapy of solid tumors; evaluation of biomarkers for radiotherapy.

  6. Six fractions per week of external beam radiotherapy and high-dose-rate brachytherapy for carcinoma of the uterine cervix: A phase I/II study

    International Nuclear Information System (INIS)

    Yoon, Sang Min; Huh, Seung Jae; Park, Won; Lee, Jeung Eun; Park, Young Je; Nam, Hee Rim; Lim, Do Hoon; Ahn, Yong Chan

    2006-01-01

    Purpose: This study evaluated the treatment results of external beam radiotherapy administered in six fractions per week and high-dose-rate (HDR) brachytherapy for the treatment of cervical cancer. Methods and Materials: From July 2000 to July 2003, 43 patients were enrolled in this study. The patients received 45 Gy from a 10-MV photon beam using four-field box or anterior-posterior beams. Parametrial regions and the pelvic side walls were boosted with up to 50.4 Gy using a midline block. The daily fraction dose was 1.8 Gy administered in six-weekly fractions, from Monday to Saturday. HDR brachytherapy was also delivered at doses of 24 Gy to point A in six fractions twice a week. The median follow-up time was 37 months (range, 9-60 months). Results: The median overall treatment time was 51 days for all patients (range, 44-62 days). Thirty-four patients (79.1%) achieved complete remission and 8 (18.6%) achieved partial remission after radiotherapy. Locoregional recurrence occurred in 5 patients (11.6%), and a distant metastasis was encountered in 6 patients (13.9%). The 3-year overall survival, locoregional, and distant metastasis-free survival rates were 74.7%, 87.8%, and 84.7%, respectively. Grade 2 and 3 late rectal complications were encountered in 3 (6.5%) and 1 (2.2%), respectively. There were no Grade 3 late bladder complications. Conclusions: Six fractions per week of external beam radiotherapy and HDR brachytherapy is an effective treatment for patients with a carcinoma of the uterine cervix and can be used as a possible alternative to concomitant chemoradiotherapy in elderly patients or in patients with co-morbidity

  7. Genome-wide transcription responses to synchrotron microbeam radiotherapy.

    Science.gov (United States)

    Sprung, Carl N; Yang, Yuqing; Forrester, Helen B; Li, Jason; Zaitseva, Marina; Cann, Leonie; Restall, Tina; Anderson, Robin L; Crosbie, Jeffrey C; Rogers, Peter A W

    2012-10-01

    The majority of cancer patients achieve benefit from radiotherapy. A significant limitation of radiotherapy is its relatively low therapeutic index, defined as the maximum radiation dose that causes acceptable normal tissue damage to the minimum dose required to achieve tumor control. Recently, a new radiotherapy modality using synchrotron-generated X-ray microbeam radiotherapy has been demonstrated in animal models to ablate tumors with concurrent sparing of normal tissue. Very little work has been undertaken into the cellular and molecular mechanisms that differentiate microbeam radiotherapy from broad beam. The purpose of this study was to investigate and compare the whole genome transcriptional response of in vivo microbeam radiotherapy versus broad beam irradiated tumors. We hypothesized that gene expression changes after microbeam radiotherapy are different from those seen after broad beam. We found that in EMT6.5 tumors at 4-48 h postirradiation, microbeam radiotherapy differentially regulates a number of genes, including major histocompatibility complex (MHC) class II antigen gene family members, and other immunity-related genes including Ciita, Ifng, Cxcl1, Cxcl9, Indo and Ubd when compared to broad beam. Our findings demonstrate molecular differences in the tumor response to microbeam versus broad beam irradiation and these differences provide insight into the underlying mechanisms of microbeam radiotherapy and broad beam.

  8. Historical review of radiotherapy

    International Nuclear Information System (INIS)

    Onai, Yoshio

    1993-01-01

    The techniques of radiotherapy have been improved by development of particle accelerators, radionuclides and computers. This paper presents a historical review of the physical and technical aspects of radiotherapy in Japan. Changes in the kinds of radiation, such as X-rays, gamma rays, electrons, neutrons and protons used for external radiotherapy, and the equipment involved are described chronologically, and historical changes in the quality of radiotherapy apparatus are outlined. Patient data acquisition equipment, such as X-ray simulator and X-ray CT, beam modifying devices, patient setup devices, and devices to verify treatment fields and patient doses are reviewed historically. Radiation sources for brachytherapy and internal radiotherapy, and remotely controlled afterloading systems are reviewed chronologically. Historical changes in methods to evaluate absorbed doses, dose monitor systems and beam data acquisition systems are outlined. Changes in methods of calculating dose distributions for external X-ray and electron therapy, brachytherapy and internal radiotherapy by unsealded radionuclides are described and calculation techniques for treatment planning system are reviewed. Annual figures in the numbers of radiotherapy equipment, such as telecobalt and telecesium units, linear accelerators, betatrons, microtrons, stereotactic gamma units, conformation radiotherapy units, remotely controlled afterloading systems, and associated equipment such as X-ray simulators and treatment planning systems are provided, as are changes in the number of accelerators by maximum X-ray energy and maximum electron energy, and in the number of licensed hospitals and clinics using small sealed sources. Changes in techniques of external radiotherapy and brachytherapy are described briefly from the point of view of dose distributions. (author)

  9. Radiological incidents in radiotherapy

    International Nuclear Information System (INIS)

    Hobzova, L.; Novotny, J.

    2008-01-01

    In many countries a reporting system of radiological incidents to national regulatory body exists and providers of radiotherapy treatment are obliged to report all major and/or in some countries all incidents occurring in institution. State Office for Nuclear Safety (SONS) is providing a systematic guidance for radiotherapy departments from 1997 by requiring inclusion of radiation safety problems into Quality assurance manual, which is the basic document for obtaining a license of SONS for handling with sources of ionizing radiation. For that purpose SONS also issued the recommendation 'Introduction of QA system for important sources in radiotherapy-radiological incidents' in which the radiological incidents are defined and the basic guidance for their classification (category A, B, C, D), investigation and reporting are given. At regular periods the SONS in co-operation with radiotherapy centers is making a survey of all radiological incidents occurring in institutions and it is presenting obtained information in synoptic communication (2003 Motolske dny, 2005 Novy Jicin). This presentation is another summary report of radiological incidents that occurred in our radiotherapy institutions during last 3 years. Emphasis is given not only to survey and statistics, but also to analysis of reasons of the radiological incidents and to their detection and prevention. Analyses of incidents in radiotherapy have led to a much broader understanding of incident causation. Information about the error should be shared as early as possible during or after investigation by all radiotherapy centers. Learning from incidents, errors and near misses should be a part of improvement of the QA system in institutions. Generally, it is recommended that all radiotherapy facilities should participate in the reporting, analyzing and learning system to facilitate the dissemination of knowledge throughout the whole country to prevent errors in radiotherapy.(authors)

  10. Dosimetric intercomparison of permanent Ho-166 seed's implants and HDR Ir-192 brachytherapy in breast cancer.

    Science.gov (United States)

    de Campos, Tarcisio Passos Ribeiro; Nogueira, Luciana Batista; Trindade, Bruno; Cuperschmid, Ethel Mizrahy

    2016-01-01

    To provide a comparative dosimetric analysis of permanent implants of Ho(166)-seeds and temporary HDR Ir(192)-brachytherapy through computational simulation. Brachytherapy with Ir(192)-HDR or LDR based on temporary wires or permanent radioactive seed implants can be used as dose reinforcement for breast radiation therapy. Permanent breast implants have not been a practical clinical routine; although, I(125) and Pd(103)-seeds have already been reported. Biodegradable Ho(166)-ceramic-seeds have been addressed recently. Simulations of implants of nine Ho(166)-seeds and equivalent with HDR Ir(192)-brachytherapy were elaborated in MCNP5, shaped in a computational multivoxel simulator which reproduced a female thorax phantom. Spatial dose rate distributions and dose-volume histograms were generated. Protocol's analysis involving exposure time, seed's activities and dose were performed. Permanent Ho(166)-seed implants presented a maximum dose rate per unit of contained activity (MDR) of 1.1601 μGy h(-1) Bq(-1); and, a normalized MDR in standard points (8 mm, equidistant to 03-seeds - SP1, 10 mm - SP2) of 1.0% (SP1) and 0.5% (SP2), respectively. Ir(192)-brachytherapy presented MDR of 4.3945 × 10(-3) μGy h(-1) Bq(-1); and, 30% (SP1), and 20% (SP2). Therefore, seed's implant activities of 333 MBq (Ho(166)) and 259 GBq (Ir(192)) produced prescribed doses of 58 Gy (SP1; 5d) and 56 Gy (SP1, 5 fractions, 6 min), respectively. Breast Ho(166)-implants of 37-111 MBq are attractive due to the high dose rate near 6-10 mm from seeds, equivalent to Ir(192)-brachytherapy of 259 GBq (3 fractions, 6 min) providing similar dose in standard points at a week; however, with spatial dose distribution better confined. The seed positioning can be adjusted for controlling the breast tumor, in stages I and II, in flat and deep tumors, without any breast volumetric limitation.

  11. Comparison of air-kerma strength determinations for HDR {sup 192}Ir sources

    Energy Technology Data Exchange (ETDEWEB)

    Rasmussen, Brian E.; Davis, Stephen D.; Schmidt, Cal R.; Micka, John A.; DeWerd, Larry A. [Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)

    2011-12-15

    Purpose: To perform a comparison of the interim air-kerma strength standard for high dose rate (HDR) {sup 192}Ir brachytherapy sources maintained by University of Wisconsin Accredited Dosimetry Calibration Laboratory (UWADCL) with measurements of the various source models using modified techniques from the literature. The current interim standard was established by Goetsch et al. in 1991 and has remained unchanged to date. Methods: The improved, laser-aligned seven-distance apparatus of University of Wisconsin Medical Radiation Research Center (UWMRRC) was used to perform air-kerma strength measurements of five different HDR {sup 192}Ir source models. The results of these measurements were compared with those from well chambers traceable to the original standard. Alternative methodologies for interpolating the {sup 192}Ir air-kerma calibration coefficient from the NIST air-kerma standards at {sup 137}Cs and 250 kVp x rays (M250) were investigated and intercompared. As part of the interpolation method comparison, the Monte Carlo code EGSnrc was used to calculate updated values of A{sub wall} for the Exradin A3 chamber used for air-kerma strength measurements. The effects of air attenuation and scatter, room scatter, as well as the solution method were investigated in detail. Results: The average measurements when using the inverse N{sub K} interpolation method for the Classic Nucletron, Nucletron microSelectron, VariSource VS2000, GammaMed Plus, and Flexisource were found to be 0.47%, -0.10%, -1.13%, -0.20%, and 0.89% different than the existing standard, respectively. A further investigation of the differences observed between the sources was performed using MCNP5 Monte Carlo simulations of each source model inside a full model of an HDR 1000 Plus well chamber. Conclusions: Although the differences between the source models were found to be statistically significant, the equally weighted average difference between the seven-distance measurements and the well

  12. Comparison of air-kerma strength determinations for HDR 192Ir sources

    International Nuclear Information System (INIS)

    Rasmussen, Brian E.; Davis, Stephen D.; Schmidt, Cal R.; Micka, John A.; DeWerd, Larry A.

    2011-01-01

    Purpose: To perform a comparison of the interim air-kerma strength standard for high dose rate (HDR) 192 Ir brachytherapy sources maintained by University of Wisconsin Accredited Dosimetry Calibration Laboratory (UWADCL) with measurements of the various source models using modified techniques from the literature. The current interim standard was established by Goetsch et al. in 1991 and has remained unchanged to date. Methods: The improved, laser-aligned seven-distance apparatus of University of Wisconsin Medical Radiation Research Center (UWMRRC) was used to perform air-kerma strength measurements of five different HDR 192 Ir source models. The results of these measurements were compared with those from well chambers traceable to the original standard. Alternative methodologies for interpolating the 192 Ir air-kerma calibration coefficient from the NIST air-kerma standards at 137 Cs and 250 kVp x rays (M250) were investigated and intercompared. As part of the interpolation method comparison, the Monte Carlo code EGSnrc was used to calculate updated values of A wall for the Exradin A3 chamber used for air-kerma strength measurements. The effects of air attenuation and scatter, room scatter, as well as the solution method were investigated in detail. Results: The average measurements when using the inverse N K interpolation method for the Classic Nucletron, Nucletron microSelectron, VariSource VS2000, GammaMed Plus, and Flexisource were found to be 0.47%, -0.10%, -1.13%, -0.20%, and 0.89% different than the existing standard, respectively. A further investigation of the differences observed between the sources was performed using MCNP5 Monte Carlo simulations of each source model inside a full model of an HDR 1000 Plus well chamber. Conclusions: Although the differences between the source models were found to be statistically significant, the equally weighted average difference between the seven-distance measurements and the well chambers was 0.01%, confirming that

  13. Comparison of air-kerma strength determinations for HDR (192)Ir sources.

    Science.gov (United States)

    Rasmussen, Brian E; Davis, Stephen D; Schmidt, Cal R; Micka, John A; Dewerd, Larry A

    2011-12-01

    To perform a comparison of the interim air-kerma strength standard for high dose rate (HDR) (192)Ir brachytherapy sources maintained by the University of Wisconsin Accredited Dosimetry Calibration Laboratory (UWADCL) with measurements of the various source models using modified techniques from the literature. The current interim standard was established by Goetsch et al. in 1991 and has remained unchanged to date. The improved, laser-aligned seven-distance apparatus of the University of Wisconsin Medical Radiation Research Center (UWMRRC) was used to perform air-kerma strength measurements of five different HDR (192)Ir source models. The results of these measurements were compared with those from well chambers traceable to the original standard. Alternative methodologies for interpolating the (192)Ir air-kerma calibration coefficient from the NIST air-kerma standards at (137)Cs and 250 kVp x rays (M250) were investigated and intercompared. As part of the interpolation method comparison, the Monte Carlo code EGSnrc was used to calculate updated values of A(wall) for the Exradin A3 chamber used for air-kerma strength measurements. The effects of air attenuation and scatter, room scatter, as well as the solution method were investigated in detail. The average measurements when using the inverse N(K) interpolation method for the Classic Nucletron, Nucletron microSelectron, VariSource VS2000, GammaMed Plus, and Flexisource were found to be 0.47%, -0.10%, -1.13%, -0.20%, and 0.89% different than the existing standard, respectively. A further investigation of the differences observed between the sources was performed using MCNP5 Monte Carlo simulations of each source model inside a full model of an HDR 1000 Plus well chamber. Although the differences between the source models were found to be statistically significant, the equally weighted average difference between the seven-distance measurements and the well chambers was 0.01%, confirming that it is not necessary to

  14. Success Stories in Radiotherapy Development Projects: Lessons Learned from Radiotherapy Development Projects. Chapter 29

    International Nuclear Information System (INIS)

    Zubizarreta, E.; Van Der Merwe, D.

    2017-01-01

    This chapter examines some problems found to be common in the process of setting up, running or expanding radiotherapy facilities. The establishment of radiotherapy services is essential to consolidate any national cancer control plan. In other words, such a plan cannot exist without radiotherapy. The IAEA guidance on setting up a radiotherapy programme covering the clinical, medical physics, radiation protection and safety aspects gives an estimate of one teletherapy machine needed per million population]. The IAEA’s Directory of Radiotherapy Centres (DIRAC) shows that the number of megavoltage (MV) machines per million population varies from 8.2 in the United States of America to 5.5 in western Europe. There are still many countries without a single radiotherapy department, especially in Africa, and many others have very low coverage, e.g. up to one external beam radiotherapy machine to cover a population of 35 million, which is close to having no coverage. There are many possible reasons for this situation. In many low income countries, the combination of lower life expectancy, low income taxes, a small budget for public health, and unmet basic needs such as housing, prevention and/or treatment of infectious diseases (malaria, tuberculosis, human immunodeficiency virus (HIV), diarrhoea), drinkable water and sewerage makes the cancer control problem a lower priority. The indicators shown illustrate these points. Establishing a radiotherapy programme requires careful planning, including the requirement for successive phases. Resources should be available for designing, building, purchasing, maintaining and replacing equipment, and for providing training in its use. In the case of a first radiotherapy facility with basic staffing levels, there is not likely to be enough expertise to guide and oversee the process in many or all of these areas.

  15. Patient Radiation Protection in Radiotherapy

    International Nuclear Information System (INIS)

    Hegazy, M.

    2010-01-01

    The Role of Radiotherapy is treatment modalities for cancer which is generally assumed that 50 to 60% of cancer patients will benefit from radiotherapy. It constitutes a peaceful application of ionizing radiation and an essential part of cancer management. The two aims of radiation protection Prevention is of deterministic effect and Reduction of the probability of stochastic effects. The Shielding fundamentals is to limit radiation exposure of staff, patients, visitors and the public to acceptable levels it also optimize protection of patients, staff and the public. Diagnosis is important for target design and the dose required for cure or palliation while Simulator is often used twice in the radiotherapy process where Patient data acquisition - target localization, contours, outlines and Verification. The Prescription is the responsibility of individual clinicians, depending on the patient’s condition, equipment available, experience and training. An ultimate check of the actual treatment given can only be made by using in vivo dosimetry. Treatment records must be kept of all relevant aspects of the treatment – including Session and Summary Record information, Records all treatment parameters, Dose Calculations and Dose Measurements

  16. Conformal radiotherapy: principles and classification

    International Nuclear Information System (INIS)

    Rosenwald, J.C.; Gaboriaud, G.; Pontvert, D.

    1999-01-01

    'Conformal radiotherapy' is the name fixed by usage and given to a new form of radiotherapy resulting from the technological improvements observed during the last ten years. While this terminology is now widely used, no precise definition can be found in the literature. Conformal radiotherapy refers to an approach in which the dose distribution is more closely 'conformed' or adapted to the actual shape of the target volume. However, the achievement of a consensus on a more specific definition is hampered by various difficulties, namely in characterizing the degree of 'conformality'. We have therefore suggested a classification scheme be established on the basis of the tools and the procedures actually used for all steps of the process, i.e., from prescription to treatment completion. Our classification consists of four levels: schematically, at level 0, there is no conformation (rectangular fields); at level 1, a simple conformation takes place, on the basis of conventional 2D imaging; at level 2, a 3D reconstruction of the structures is used for a more accurate conformation; and level 3 includes research and advanced dynamic techniques. We have used our personal experience, contacts with colleagues and data from the literature to analyze all the steps of the planning process, and to define the tools and procedures relevant to a given level. The corresponding tables have been discussed and approved at the European level within the Dynarad concerted action. It is proposed that the term 'conformal radiotherapy' be restricted to procedures where all steps are at least at level 2. (author)

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

    International Nuclear Information System (INIS)

    Lee, B; Grelewicz, Z; Kang, Z; Cutright, D; Gopalakrishnan, M; Sathiaseelan, V; Zhang, H

    2016-01-01

    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.

  18. Dosimetric evaluation of a novel high dose rate (HDR) intraluminal / interstitial brachytherapy applicator for gastrointestinal and bladder cancers

    Science.gov (United States)

    Aghamiri, Seyyed Mahmoud Reza; Najarian, Siamak; Jaberi, Ramin

    2010-01-01

    High dose rate (HDR) brachytherapy is one of the accepted treatment modalities in gastro‐intestinal tract and bladder carcinomas. Considering the shortcoming of contact brachytherapy routinely used in gastrointestinal tract in treatment of big tumors or invasive method of bladder treatment, an intraluminal applicator with the capability of insertion into the tumor depth seems to be useful. This study presents some dosimetric evaluations to introduce this applicator to the clinical use. The radiation attenuation characteristics of the applicator were evaluated by means of two dosimetric methods including well‐type chamber and radiochromic film. The proposed 110 cm long applicator has a flexible structure made of stainless steel for easy passage through lumens and a needle tip to drill into big tumors. The 2 mm diameter of the applicator is thick enough for source transition, while easy passage through any narrow lumen such as endoscope or cystoscope working channel is ensured. Well‐chamber results showed an acceptably low attenuation of this steel springy applicator. Performing absolute dosimetry resulted in a correlation coefficient of R=0.9916(p‐value≈10−7) between standard interstitial applicator and the one proposed in this article. This study not only introduces a novel applicator with acceptable attenuation but also proves the response independency of the GAFCHROMIC EBT films to energy. By applying the dose response of the applicator in the treatment planning software, it can be used as a new intraluminal / interstitial applicator. PACS number: 87.53.Bn, 87.53.Jw, 29.40.Cs

  19. 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.

  20. 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.

  1. The metabolic radiotherapy

    International Nuclear Information System (INIS)

    Begon, F.; Gaci, M.

    1993-01-01

    In this article, the authors recall the principles of the metabolic radiotherapy and present these main applications in the treatment of thyroid cancers, hyperthyroidism, polycythemia, arthritis, bone metastases, adrenergic neoplasms. They also present the radioimmunotherapy

  2. The potential of radiotherapy of lymphoma infiltrations of the CNS

    International Nuclear Information System (INIS)

    Coupek, P.; Hanova, I.; Pohankova, R.

    1997-01-01

    Radiotherapy is a very important element in the complex therapy of lymphomas of the central nervous system, significantly improving the results of the aggressive system chemotherapy. Irradiation of considerable tissue volumes and the application of rather high total doses are recommended. In view of the unfavorable prognosis and biological behavior of the tumor, the total treatment (including chemotherapy and radiotherapy) should be aggressive. (author)

  3. Proceedings of 19. symposium on experimental radiotherapy and clinical radiobiology

    International Nuclear Information System (INIS)

    Baumann, Michael; Dahm-Daphi, Jochen; Dikomey, Ekkehard; Petersen, Cordula; Rodemann, H. Peter; Zips, Daniel

    2010-01-01

    The proceedings include review contributions on radio-oncology, and new radiation technologies and molecular prediction; and poster sessions on the following topics: hypoxia; molecular mechanisms of radiation resistance; molecular targeting; DNA repair; biological imaging; biology of experimental radiations; normal tissue toxicity; modern radiotherapy; tumor hypoxia and metabolic micro milieu; immune system and radiotherapy.

  4. Experimental and theoretical investigations of soil-structure interaction effect at HDR-reactor-building

    International Nuclear Information System (INIS)

    Wassermann, K.

    1983-01-01

    Full-scale dynamic testing on intermediate and high levels was performed at the Heissdampfreaktor (HDR) in 1979. Various types of dynamic forces were applied and response of the reactor containment structure and internal components was measured. Precalculations of dynamic behaviour and response of the structure were made through different mathematical models for the structure and the underlying soil. Soil-Structure Interaction effects are investigated and different theoretical models are compared with experimental results. In each model, the soil is represented by springs attached to the structural model. Stiffnesses of springs are calculated by different finite-element idealizations and half-space approximations. Eigenfrequencies and damping values related to interaction effects (translation, rocking, torsion) are identified from test results. The comparisons of dynamic characteristic of the soil-structure system between precalculations and test results show good agreement in general. (orig.)

  5. SW England seismic monitoring for the HDR geothermal programme in Cornwall 1989 to September 1991

    International Nuclear Information System (INIS)

    Walker, A.B.

    1992-01-01

    The potential for earthquakes to be triggered by fluid injected into boreholes has been recognised for 25 years and natural earthquakes in Cornwall have been reported for over 250 years. As a result, the Geothermal Steering Committee advising the Hot Dry Rock project recommended that background seismic monitoring be undertaken around the HDR experimental site at Rosemanowes. A network of seismographs was established for this purpose by the British Geological Survey (BGS) in late 1980 and has been operated continuously through September 1991. The primary aim of the network has been to provide an independent, continuous assessment of all vibrational transients in order to discriminate between those caused by the Hot Dry Rock experiments and those of natural origin or from other man-made sources. In this respect, the work provides an insurance against claims that extraneous seismic activity is related to those experiments. (author)

  6. Structural safety of HDR reactor building during large scale vibration tests

    International Nuclear Information System (INIS)

    Stangenberg, F.; Zinn, R.

    1985-01-01

    In the second phase of the HDR investigations, a high shaker excitation of the building is planned using a large shaker which will be located on the operating floor and will be brought up to speed in a balanced condition and then unbalanced and decoupled from the drive system. With decreasing speed the shaker comes in resonance with the building frequencies and its energy is transferred to the building. In this paper the structural safety of the reactor building during the projected shaker tests is analysed. Dynamic response calculations with coupling between building and shaker by simultaneously integrating the equilibrium equations of both building and shaker are presented. The resulting building stresses, soil pressures etc. are compared with allowable values. (orig.)

  7. Comparison of leak opening and leak rate calculations to HDR experimental results

    International Nuclear Information System (INIS)

    Grebner, H.; Hoefler, A.; Hunger, H.

    1993-01-01

    During the last years a number of calculations of leak opening and leak rate for through cracks in piping components have been performed. Analyses are pre- or mostly post-calculations to experiments performed at the HDR facility under PWR operating conditions. Piping components under consideration were small diameter straight pipes with circumferential cracks, pipe bends with longitudinal or circumferential cracks and pipe branches with weldment cracks. The components were loaded by internal pressure and opening as well as closing bending moment. The finite element method and two-phase flow leak rate programs were used for the calculations. Results of the analyses are presented as J-integral values, crack opening displacements and areas and leak rates as well as comparisons to the experimental results

  8. Accurate assessment of the distortions produced by the transit dose in HDR brachytherapy

    International Nuclear Information System (INIS)

    Nani, E.K.; Kyere, A.W.K.; Tetteh, K.

    2001-01-01

    Current polynomial methods used in the modelling of the dose distributions in HDR brachytherapy have been reformulated to improve accuracy. An example is provided to show the effects of the transit dose on the output. The transit dose, which is neglected by current computer software for calculating doses, can result in significant dosimetric errors. These additional unrecognised doses imply over-dosing and distortions in the dose distributions within the irradiated volume. Assessment of dose to critical and radiosensitive organs is therefore inaccurate. These could increase late tissue complications as predicted by the Linear Quadratic Model. Our model works very well for straight catheters and is highly recommended for the evaluation of the transit dose around such catheters. (author)

  9. Heissdampfreaktor (HDR) steel-containment-vessel and floodwater-storage-tank structural-dynamics tests

    International Nuclear Information System (INIS)

    Arendts, J.G.

    1982-01-01

    Inertance (vibration) testing of two significant vessels at the Heissdampfreaktor (HDR) facility, located near Kahl, West Germany, was recently completed. Transfer functions were obtained for determination of the modal properties (frequencies, mode shapes and damping) of the vessels using two different test methods for comparative purposes. One of the vessels tested was the steel containment vessel (SCV). The SCV is approximately 180 feet high and 65 feet in diameter with a 1.2-inch wall thickness. The other vessel, called the floodwater storage tank (FWST), is a vertically standing vessel approximately 40 feet high and 10 feet in diameter with a 1/2-inch wall thickness. The FWST support skirt is square (in plan views) with its corners intersecting the ellipsoidal bottom head near the knuckle region

  10. 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.

  11. Clinical practice of radiotherapy

    International Nuclear Information System (INIS)

    Tobias, J.S.

    1992-01-01

    After describing the recent advances in radiotherapy, this brief article presents in tabular form the changing indications for radiotherapy for tumours of the skin, head and neck, adult CNS, lung, thyroid, thymus, breast, female genital tract, soft tissue sarcoma, genitourinary tract, bone sarcoma, Hodgkin's disease, non-Hodgkin lymphoma, multiple myeloma, leukemia and paediatric malignancy. For each tumour type, information is provided for the radiosensitivity, the radiocurability, complications and five-year survival. Combined modality treatment is also briefly discussed. (UK)

  12. Nanoparticle-guided radiotherapy

    DEFF Research Database (Denmark)

    2012-01-01

    The present invention relates to a method and nano-sized particles for image guided radiotherapy (IGRT) of a target tissue. More specifically, the invention relates to nano-sized particles comprising X-ray-imaging contrast agents in solid form with the ability to block x-rays, allowing for simult...... for simultaneous or integrated external beam radiotherapy and imaging, e.g., using computed tomography (CT)....

  13. Clinical practice of radiotherapy

    International Nuclear Information System (INIS)

    Horiuchi, Junichi; Masaki, Norie; Onoyama, Yasuto

    1987-01-01

    This chapter presents in greater detail radiotherapy used in each clinical setting. The descriptions are given under the following sections: the tongue and oral cavity; the maxilla, larynx, and pharynx; brain tumors; the eyes and orbit; pediatric tumors; lung cancer; the esophagus; breast cancer; the abdominal digestive system; the urogenital system; the uterine cervix; the ovaries and vulva; bone and soft tissues; the skin; hematopoietic tumors; lymph node metastases; and radiotherapy as palliative treatment. (Namekawa, K.)

  14. Patients and radiotherapy

    International Nuclear Information System (INIS)

    Eardley, A.

    1986-01-01

    The results of interviews with thirty discharged patients who had undergone radical radiotherapy for cancer of the head and neck are presented. Patients were asked whether their side-effects had got worse or had stayed the same, what effect their side effects had had on eating and drinking and whether they had felt depressed during this period. Measures which could be taken to improve patients' experiences of radiotherapy are discussed. (U.K.)

  15. Radiotherapy and oral cancer

    Energy Technology Data Exchange (ETDEWEB)

    Sealy, R [Cape Town Univ. (South Africa). Dept. of Radiotherapy

    1982-08-01

    A general review article for the non-radiotherapist. The historical, physical and biological background is briefly reviewed. Mention is made of the effects of fraction size, hyperbaric oxygen, neutron beams and radiation sensitizers. The use of chemotherapy and radiotherapy is discussed, as well as the selection of patients for radiotherapy and the treatment of neck nodes. The author suggests a therapeutic approach to the various disease sites and finally reviews some of the literature on radiation caries and jaw necrosis.

  16. Radioprotectors in Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Nair, C.K.K. [Bhabha Atomic Research Centre, Mumbai (India); Parida, D.K.; Nomura, Taisei

    2001-03-01

    This review article focuses on clinically relevant radioprotectors and their mechanisms of radioprotection. Radiotherapy is the most common modality of human cancer therapy. Obtaining optimal results requires a judicious balance between the total dose of radiotherapy delivered and the threshold limit of critical surrounding normal tissues, and the normal tissues need to be protected against radiation injury to obtain better tumor control by using a higher dose. For this reason, radiation-protective agents play an important role in clinical radiotherapy. Radiation-protective agents can be classified into three groups: radioprotectors, adaptogens, and absorbents. The first group generally consists of sulfhydryl compounds and other antioxidants. They include several myelo-, entero-, and cerebro-protectors. Adaptogens act as promotors of radioresistance. They are natural protectors that offer chemical protection against low levels of ionizing radiation. Absorbents protect organs from internal radiation and chemicals. They include drugs that prevent incorporation of radioiodine by the thyroid gland and absorption of radionuclides. This article thoroughly describes the properties, mechanisms of action, and perspectives on clinical application of the following categories of radioprotectors: sulfhydryl compounds (e.g., cysteine, cysteamine, glutathione, AET, WR 2127, and other WR-compounds), antioxidants (e.g., tempace, Hoechst 33342, vitamin A, E, and C, TMG, melatonin), angiotensin-converting enzyme (ACE) inhibitors (e.g., captopril, elanopril, penicillamine, pentoxifylline, L-158, 809), cytoprotective agents (mesna, dexrazoxane, and amifostin), metalloelements (e.g., manganese chloride, cadmium salts, bismuth subnitrate), immunomodulators (gamma-interferon, polysaccharides AM5, AM218, heat-killed lactobacillus cells, broncho-vaxom, trehalose dicorynomycolate, and AS101), lipopolysaccharides and prostaglandins, plant extracts and compounds isolated from plants (curcmin

  17. Dosimetric comparison between the microSelectron HDR 192Ir v2 source and the BEBIG 60Co source for HDR brachytherapy using the EGSnrc Monte Carlo transport code

    International Nuclear Information System (INIS)

    Anwarul Islam, M.; Akramuzzaman, M.M.; Zakaria, G.A.

    2012-01-01

    Manufacturing of miniaturized high activity 192 Ir sources have been made a market preference in modern brachytherapy. The smaller dimensions of the sources are flexible for smaller diameter of the applicators and it is also suitable for interstitial implants. Presently, miniaturized 60 Co HDR sources have been made available with identical dimensions to those of 192 Ir sources. 60 Co sources have an advantage of longer half life while comparing with 192 Ir source. High dose rate brachytherapy sources with longer half life are logically pragmatic solution for developing country in economic point of view. This study is aimed to compare the TG-43U1 dosimetric parameters for new BEBIG 60 Co HDR and new microSelectron 192 Ir HDR sources. Dosimetric parameters are calculated using EGSnrc-based Monte Carlo simulation code accordance with the AAPM TG-43 formalism for microSelectron HDR 192 Ir v2 and new BEBIG 60 Co HDR sources. Air-kerma strength per unit source activity, calculated in dry air are 9.698x10 -8 ± 0.55% U Bq -1 and 3.039x10 -7 ± 0.41% U Bq -1 for the above mentioned two sources, respectively. The calculated dose rate constants per unit air-kerma strength in water medium are 1.116±0.12% cGy h -1 U -1 and 1.097±0.12% cGy h -1 U -1 , respectively, for the two sources. The values of radial dose function for distances up to 1 cm and more than 22 cm for BEBIG 60 Co HDR source are higher than that of other source. The anisotropic values are sharply increased to the longitudinal sides of the BEBIG 60 Co source and the rise is comparatively sharper than that of the other source. Tissue dependence of the absorbed dose has been investigated with vacuum phantom for breast, compact bone, blood, lung, thyroid, soft tissue, testis, and muscle. No significant variation is noted at 5 cm of radial distance in this regard while comparing the two sources except for lung tissues. The true dose rates are calculated with considering photon as well as electron transport using

  18. Relationship between in vitro chromosomal radiosensitivity of peripheral blood lymphocytes and the expression of normal tissue damage following radiotherapy for breast cancer

    International Nuclear Information System (INIS)

    Barber, J.B.P.; Burrill, W.; Spreadborough, A.R.; Levine, E.; Warren, C.; Scott, D.; Kiltie, A.E.; Roberts, S.A.

    2000-01-01

    There is a need for rapid and reliable tests for the prediction of normal tissue responses to radiotherapy, as this could lead to individualization of patient radiotherapy schedules and thus improvements in the therapeutic ratio. Because the use of cultured fibroblasts is too slow to be practicable in a clinical setting, we evaluated the predictive role of assays of lymphocyte chromosomal radiosensitivity in patients having radiotherapy for breast cancer. Radiosensitivity was assessed using a macronucleus (MN) assay at high dose rate (HDR) and low dose rate (LDR) on lymphocytes irradiated in the G 0 phase of the cell cycle (Scott D, Barber JB, Levine EL, Burril W, Roberts SA. Radiation-induced micronucleus induction in lymphocytes identifies a frequency of radiosensitive cases among breast cancer patients: a test for predisposition? Br. J. Cancer 1998;77;614-620) and an assay of G 2 phase chromatid radiosensitivity ('G 2 assay') (Scott D, Spreadborough A, Levine E, Roberts SA. Genetic predisposition in breast cancer. Lancet 1994; 344: 1444). In a study of acute reactions, blood samples were taken from breast cancer patients before the start of radiotherapy, and the skin reaction documented. 116 patients were tested with the HDR MN assay, 73 with the LDR MN assay and 123 with the G 2 assay. In a study of late reactions, samples were taken from a series of breast cancer patients 8-14 years after radiotherapy and the patients assessed for the severity of late effects according to the 'LENT SOMA' scales. 47 were tested with the HDR assay, 26 with the LDR assay and 19 with the G 2 assay. For each clinical endpoint, patients were classified as being normal reactors or 'highly radiosensitive patients' (HR patients (Burnet NG. Johansen J, Turesson I, Nyman J. Describing patients' normal tissue reactions: Concerning the possibility of individualising radiotherapy dose prescriptions based on potential predictive assays of normal tissue radiosensitivity. Int. J. Cancer 1998

  19. 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.

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

    International Nuclear Information System (INIS)

    Calcina, Carmen S Guzman; Almeida, Adelaide de; Rocha, Jose R Oliveira; Abrego, Felipe Chen; Baffa, Oswaldo

    2005-01-01

    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)

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

    International Nuclear Information System (INIS)

    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 D 90% 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 D 90% 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 D 90% against uncertainty in dwell positions for both models. (paper)

  2. TU-D-201-06: HDR Plan Prechecks Using Eclipse Scripting API

    Energy Technology Data Exchange (ETDEWEB)

    Palaniswaamy, G; Morrow, A; Kim, S; Rangaraj, D [Baylor Scott & White Health, Temple, TX (United States)

    2016-06-15

    Purpose: Automate brachytherapy treatment plan quality check using Eclipse v13.6 scripting API based on pre-configured rules to minimize human error and maximize efficiency. Methods: The HDR Precheck system is developed based on a rules-driven approach using Eclipse scripting API. This system checks for critical plan parameters like channel length, first source position, source step size and channel mapping. The planned treatment time is verified independently based on analytical methods. For interstitial or SAVI APBI treatment plans, a Patterson-Parker system calculation is performed to verify the planned treatment time. For endobronchial treatments, an analytical formula from TG-59 is used. Acceptable tolerances were defined based on clinical experiences in our department. The system was designed to show PASS/FAIL status levels. Additional information, if necessary, is indicated appropriately in a separate comments field in the user interface. Results: The HDR Precheck system has been developed and tested to verify the treatment plan parameters that are routinely checked by the clinical physicist. The report also serves as a reminder or checklist for the planner to perform any additional critical checks such as applicator digitization or scenarios where the channel mapping was intentionally changed. It is expected to reduce the current manual plan check time from 15 minutes to <1 minute. Conclusion: Automating brachytherapy plan prechecks significantly reduces treatment plan precheck time and reduces human errors. When fully developed, this system will be able to perform TG-43 based second check of the treatment planning system’s dose calculation using random points in the target and critical structures. A histogram will be generated along with tabulated mean and standard deviation values for each structure. A knowledge database will also be developed for Brachyvision plans which will then be used for knowledge-based plan quality checks to further reduce

  3. Monte Carlo Treatment Planning for Advanced Radiotherapy

    DEFF Research Database (Denmark)

    Cronholm, Rickard

    This Ph.d. project describes the development of a workflow for Monte Carlo Treatment Planning for clinical radiotherapy plans. The workflow may be utilized to perform an independent dose verification of treatment plans. Modern radiotherapy treatment delivery is often conducted by dynamically...... modulating the intensity of the field during the irradiation. The workflow described has the potential to fully model the dynamic delivery, including gantry rotation during irradiation, of modern radiotherapy. Three corner stones of Monte Carlo Treatment Planning are identified: Building, commissioning...... and validation of a Monte Carlo model of a medical linear accelerator (i), converting a CT scan of a patient to a Monte Carlo compliant phantom (ii) and translating the treatment plan parameters (including beam energy, angles of incidence, collimator settings etc) to a Monte Carlo input file (iii). A protocol...

  4. Radiation caries - an evil eye of radiotherapy

    International Nuclear Information System (INIS)

    Lakshman, Anusha Rangare

    2013-01-01

    Although radiotherapy plays an important role in the management of patients with head and neck cancer, it is also associated with several undesired side effects such as radiation caries which is a common, yet serious, complication. The radiotherapy field of exposure frequently includes the salivary glands, oral mucosa, and jaws, thus, leading to various side effects including hyposalivation, mucositis, and taste loss. Irradiated patients are also at increased risk for the development of a rapid, rampant carious process known as radiation caries. Lesions tend to develop four weeks after completion of radiotherapy and affect atypical areas of teeth, such as the lingual surface, incisal edges, and cusp tips. The aim of this paper is to review the clinical features, prevention and management of radiation caries. (author)

  5. Hyperthermia and radiotherapy

    International Nuclear Information System (INIS)

    Dietzel, F.

    1979-01-01

    Of decisive importance for superadditive enhancement is the close temporal correlation of hyperthermia and radiotherapy. It is recommended to first irradiate and then use heat treatment in order to ensure that dividable tumour cells are irradiated before hyperthermia. To achieve an optimal enhancing effect, temperatures of appr. 42 0 are sufficient. In order to be able to neglect temperature regulation and convection effects, hyperthermia for clinical use must be carried out in doses high enough to ensure that it can be finished within 3-4 minutes. It is necessary to make efforts to find out which forms of application can be realised in order to reach deeper tissue regions, thus making possible at least a half-depth-therapy. Up to day, only the 2 cm near to the surface can be heated in a sufficiently homogeneous way. In the FRG, there are more than 200 high-volt-therapy systems, including electron accelerators and telegamma systems. This is a dense network of radiation-therapeutical supply. An improved therapy effect of loose ionising rays which, with the help of the hypertherming, would almost be equal to irradiation with high ionisation density, is not only of scientific interest, but also of high interest for public health. (orig./MG) 891 MG/orig.- 892 RDG [de

  6. All delays before radiotherapy risk progression of Merkel cell carcinoma

    International Nuclear Information System (INIS)

    Tsang, G.; O'Brien, P.; Robertson, R.; Hamilton, C.; Wratten, C.; Denham, J.

    2004-01-01

    Prolonged waiting times for radiotherapy have resulted in many centres assigning priorities to various patient or diagnostic groups. A high risk of progression on a waiting list is one factor that would reasonably influence the priority. The present descriptive study of 27 patients with Merkel cell carcinoma (MCC) found that a median wait of 24 days for radiotherapy is associated with a high risk of progression. Eleven (41%) of 27 patients developed progressive disease, including five (45%) of 11 patients waiting for adjuvant radiotherapy. Patients treated adjuvantly also had longer waiting times prior to their initial radiotherapy consultation (median 41 days), which may have contributed to the rate of progression. Merkel cell carcinoma is an aggressive but curable malignancy and appropriate management should include efforts to minimize all potential delays prior to the commencement of radiotherapy. Copyright (2004) Blackwell Science Pty Ltd

  7. Oxygenation of cervical cancers during radiotherapy and radiotherapy + cis-retinoic acid/interferon

    International Nuclear Information System (INIS)

    Dunst, Jeurgen; Heansgen, Gabriele; Lautenschleager, Christine; Feuchsel, Glenn; Becker, Axel

    1999-01-01

    Purpose: We have evaluated the tumor tissue pO 2 in cervical cancers during radiotherapy with special emphasis on the course of the pO 2 in primarily hypoxic tumors and in patients treated with radiotherapy plus 13-cis-retinoic acid/interferon-α-2a. Methods and Materials: From June 1995 through April 1997, 49 patients with squamous cell carcinoma FIGO IIB-IVA of the cervix who were treated with definitve radiotherapy with curative intent underwent polarographic measurement of tumor tissue pO 2 with an Eppendorf pO 2 -histograph prior to and during radiation treatment. Radiotherapy consisted of external irradiation with 50.4 Gy in 28 fractions of 1.8 Gy plus high dose rate (HDR) brachytherapy. Twenty-two patients had additional treatment with 13-cis-retinoic acid (cRA, isotretinoin) and interferon-α-2a (IFN-α-2a). Therapy with cRA/IFN in these patients started 2 weeks before radiotherapy; during this induction period, cRA was administered in a dosage of 1 mg per kilogram body weight orally daily and IFN-α-2a in a dosage of 6 x 10 6 I.U. subcutaneously daily. After start of external radiotherapy (XRT), cRA/IFN was continued concomitantly with radiotherapy in reduced doses (0.5 mg cRA per kg body weight orally daily plus 3 x 10 6 I.U. IFN-α-2a subcutaneously three times weekly until the end of the radiation treatment). pO 2 measurements were performed prior to radiotherapy, at 20 Gy, and at the end of radiotherapy. Results: A poor oxygenation defined as a median pO 2 of 10 mm Hg or less was present in 15/38 tumors (39%) in which measurements prior to any treatment were done. Low pO 2 readings below 5 mm Hg were present in 70% of all tumors prior to treatment. In 13 of 15 hypoxic tumors, pO 2 measurements at 19.8 Gy were performed. In these tumors, a significant increase of the median pO 2 from 6.0 ± 3.1 mm Hg to 20.7 ± 21.2 mm Hg was found, p 2 was more pronounced in patients with radiotherapy plus additional cRA/IFN treatment as compared to patients treated

  8. Radiotherapy of primary gastric malignant lymphoma

    International Nuclear Information System (INIS)

    Monzen, Yoshio; Mutsukura, Masahide; Moriuchi, Yukiyoshi

    2017-01-01

    Fifteen patients with primary gastric malignant lymphoma who underwent radiotherapy were examined. Median age was 68 years, and male to female ratio was 1:2. All the cases were stage I including 7 cases of diffuse large B-cell lymphoma (DLBCL), 7 cases of MALT lymphoma, and 1 case of follicular lymphoma. Therapy methods were as follows. For DLBCL, 30 Gy of radiotherapy was performed after chemotherapy. For six cases of MALT lymphomas, 30 Gy of radiotherapy was performed. For one patient diagnosed as high-grade gastric MALT lymphoma was treated in the same way as DLBCL. For one patient with follicular lymphoma, 30 Gy of radiotherapy was performed. The radiotherapy was applied with 3-dimensional fixed multi-portal irradiation, with the reduced irradiation of the liver and kidney. There was no recurrence of disease in all cases, and all patients have been alive, and no-recurrence living periods are 20 to 120 months. There was no harmful adverse event, and the tumor had disappeared with 30 Gy of radiation therapy in all cases. Considering the occurrence of secondary cancer, it was considered that a dosage of more than 30 Gy was not necessary for primary gastric malignant lymphoma. (J.P.N.)

  9. Survey on deep learning for radiotherapy.

    Science.gov (United States)

    Meyer, Philippe; Noblet, Vincent; Mazzara, Christophe; Lallement, Alex

    2018-05-17

    More than 50% of cancer patients are treated with radiotherapy, either exclusively or in combination with other methods. The planning and delivery of radiotherapy treatment is a complex process, but can now be greatly facilitated by artificial intelligence technology. Deep learning is the fastest-growing field in artificial intelligence and has been successfully used in recent years in many domains, including medicine. In this article, we first explain the concept of deep learning, addressing it in the broader context of machine learning. The most common network architectures are presented, with a more specific focus on convolutional neural networks. We then present a review of the published works on deep learning methods that can be applied to radiotherapy, which are classified into seven categories related to the patient workflow, and can provide some insights of potential future applications. We have attempted to make this paper accessible to both radiotherapy and deep learning communities, and hope that it will inspire new collaborations between these two communities to develop dedicated radiotherapy applications. Copyright © 2018 Elsevier Ltd. All rights reserved.

  10. Quality and safety in radiotherapy

    CERN Document Server

    Pawlicki, Todd

    2010-01-01

    The first text to focus solely on quality and safety in radiotherapy, this work encompasses not only traditional, more technically oriented, quality assurance activities, but also general approaches of quality and safety. It includes contributions from experts both inside and outside the field to present a global view. The task of assuring quality is no longer viewed solely as a technical, equipment-dependent endeavor. Instead, it is now recognized as depending on both the processes and the people delivering the service. Divided into seven broad categories, the text covers: Quality Management

  11. Basic radiotherapy physics and biology

    CERN Document Server

    Chang, David S; Das, Indra J; Mendonca, Marc S; Dynlacht, Joseph R

    2014-01-01

    This book is a concise and well-illustrated review of the physics and biology of radiation therapy intended for radiation oncology residents, radiation therapists, dosimetrists, and physicists. It presents topics that are included on the Radiation Therapy Physics and Biology examinations and is designed with the intent of presenting information in an easily digestible format with maximum retention in mind. The inclusion of mnemonics, rules of thumb, and reader-friendly illustrations throughout the book help to make difficult concepts easier to grasp. Basic Radiotherapy Physics and Biology is a

  12. Advice concerning radiotherapy

    International Nuclear Information System (INIS)

    1984-01-01

    Dutch National cancer incidence figures were calculated by using the reliable data on cancer incidence in the Eindhoven area and population forecasts and information obtained from the Central Bureau of Statistics. Several radiotherapy departments suffer from under capacity (a lack of resources and understaffing). Data have also shown that 35% of cancer patients receive radiotherapy, instead of 50%. Calculations have been made by the committee on the present and future needs with regard to equipment and staff. In 1983, the number of megavoltage therapy units amounted to 38, but should have been 65. It should be 80 in 1990 and 90 in 2000. Since building and installing such equipment is a lengthy process a considerable effort is needed to make up for the arrears. The committee advocates the extension of the system of regional cooperation in cancer care (comprehensive cancer centres), in which radiotherapy departments play a crucial role. Working parties from the committee provided a comprehensive description of current radiotherapy practice with reference to physical, technical, clinical and management aspects. Another working party assessed the results of cancer treatment with regard to many different tumour sites. Recent and expected developments were analysed or indicated. The Radiotherapy Committee commissioned an external team to conduct a project to achieve a picture of future developments using methods different to those of the committee's. An interim advice has been added on this subject. (Auth.)

  13. Adjuvant high-dose-rate brachytherapy after external beam radiotherapy in nasopharyngeal carcinoma

    International Nuclear Information System (INIS)

    Oezyar, Enis; Yildz, Ferah; Akyol, Fadil H.; Atahan, I. Lale

    2002-01-01

    Purpose: To compare the local control and survival rates obtained with either external beam radiation therapy (ERT) and adjuvant high-dose-rate (HDR) brachytherapy (BRT) or ERT alone in patients with nasopharyngeal cancer. Methods and Materials: Between December 1993 and December 1999, 144 patients (106 male, 38 female) with the diagnosis of nasopharyngeal cancer were treated with either ERT and adjuvant HDR BRT (Group A) or ERT alone (Group B) at our department. BRT was not applied in 38 patients for the following reasons: (1) Unit was unavailable (n=13), (2) Patient was younger than 18 years (n=17), (3) Patient received accelerated hyperfractionated ERT (n=6), and (4) Patient refused BRT (n=2). The median age for whole group was 43 (range: 9-82 years). According to the AJCC-1997 staging system, there were 11 (7.6%), 35 (24.3%), 38 (26.4%), and 60 (41.7%) patients in Stage I, II, III, and IV, respectively. There were 57 (39.6%) patients with T1, 41 (28.5%) with T2, 20 (13.9%) with T3, and 26 (18.1%) with T4 tumors. Histopathologic diagnosis was WHO 2-3 in 137 (95.2%) patients. ERT doses ranged between 58.8 and 74 Gy (median: 66 Gy). There were significantly more patients with young age, N2 status, and Stage III disease in Group B and with Stage II disease in Group A. Significantly more patients received chemotherapy in Group B. BRT with an HDR 192 Ir microSelectron afterloading unit was delivered in 106 patients at the conclusion of ERT using a single-channel nasal applicator. Dose was prescribed at 1 cm from the source, and total dose of 12 Gy in 3 fractions on 3 consecutive days was given immediately after ERT. Besides radiotherapy, 82 (56.9%) patients received cisplatin-based chemotherapy, as well. Follow-up time ranged between 12 and 80 months (median: 32 months). Results: The two groups were comparable in terms of local recurrence, locoregional failure, regional failure, and rate of distant metastasis. Local failure was observed in 11 (10.3%) out of 106

  14. Cardiac Side-effects From Breast Cancer Radiotherapy.

    Science.gov (United States)

    Taylor, C W; Kirby, A M

    2015-11-01

    Breast cancer radiotherapy reduces the risk of cancer recurrence and death. However, it usually involves some radiation exposure of the heart and analyses of randomised trials have shown that it can increase the risk of heart disease. Estimates of the absolute risks of radiation-related heart disease are needed to help oncologists plan each individual woman's treatment. The risk for an individual woman varies according to her estimated cardiac radiation dose and her background risk of ischaemic heart disease in the absence of radiotherapy. When it is known, this risk can then be compared with the absolute benefit of the radiotherapy. At present, many UK cancer centres are already giving radiotherapy with mean heart doses of less than 3 Gy and for most women the benefits of the radiotherapy will probably far outweigh the risks. Technical approaches to minimising heart dose in breast cancer radiotherapy include optimisation of beam angles, use of multileaf collimator shielding, intensity-modulated radiotherapy, treatment in a prone position, treatment in deep inspiration (including the use of breath-hold and gating techniques), proton therapy and partial breast irradiation. The multileaf collimator is suitable for many women with upper pole left breast cancers, but for women with central or lower pole cancers, breath-holding techniques are now recommended in national UK guidelines. Ongoing work aims to identify ways of irradiating pan-regional lymph nodes that are effective, involve minimal exposure of organs at risk and are feasible to plan, deliver and verify. These will probably include wide tangent-based field-in-field intensity-modulated radiotherapy or arc radiotherapy techniques in combination with deep inspiratory breath-hold, and proton beam irradiation for women who have a high predicted heart dose from intensity-modulated radiotherapy. Copyright © 2015 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  15. 13. status report of the project HDR safety program of Kernforschungszentrum Karlsruhe. Working report 05.46/89

    International Nuclear Information System (INIS)

    Katzenmeier, G.

    1989-01-01

    The programme phase III, which extends to the end of 1991, is divided into the part projects containment behaviour in extreme accidents, long-term damage and monitoring the components in operation, behaviour of damaged components in dynamic accidents and large fires of actual materials. The main aims, state of the HDR safety programme, main points of the programme for 1990 and 8 technical reports on phase II and III are documented. There is a survey of costs. (DG) [de

  16. Radiotherapy of patients with germ cell tumor

    International Nuclear Information System (INIS)

    Inomata, Taisuke; Maeda, Tomoho; Yoshida, Shoji; Ogawa, Yasuhiro; Hamada, Fumio; Imajo, Yoshinari; Gose, Kyuhei; Fujiwara, Kiyoshi.

    1986-01-01

    Twenty-one patients with germ cell tumor who received radiotherapy were discussed. There were eight patients with germinoma, two patients with malignant teratoma, three patients with pineocytoma (out of category of germ cell tumor today) and eight unverified patients. Irradiated dose was mostly from 50 Gy to 60 Gy and local irradiation was performed after whole brain irradiation in many cases. The effect of radiotherapy was not so good in patients with malignant teratoma. On the contrary, it was relatively good in patients with germinoma and five out of eight patients are alive with no symptoms of recurrence. Six out of eight unverified patients are also alive. Among them, several patients with germinoma are considered to be included. Germinoma occupies many cases of germ cell tumor and has a good response to radiotherapy. Against spinal cord metastasis and late recurrence, additional therapy, such as chemotherapy, seems to be useful to improve cure ratio. (author)

  17. Radiotherapy for Oligometastatic Lung Cancer

    Directory of Open Access Journals (Sweden)

    Derek P. Bergsma

    2017-09-01

    Full Text Available Non-small cell lung cancer (NSCLC typically presents at an advanced stage, which is often felt to be incurable, and such patients are usually treated with a palliative approach. Accumulating retrospective and prospective clinical evidence, including a recently completed randomized trial, support the existence of an oligometastatic disease state wherein select individuals with advanced NSCLC may experience historically unprecedented prolonged survival with aggressive local treatments, consisting of radiotherapy and/or surgery, to limited sites of metastatic disease. This is reflected in the most recent AJCC staging subcategorizing metastatic disease into intra-thoracic (M1a, a single extra thoracic site (M1b, and more diffuse metastases (M1c. In the field of radiation oncology, recent technological advances have allowed for the delivery of very high, potentially ablative, doses of radiotherapy to both intra- and extra-cranial disease sites, referred to as stereotactic radiosurgery and stereotactic body radiotherapy (or SABR, in much shorter time periods compared to conventional radiation and with minimal associated toxicity. At the same time, significant improvements in systemic therapy, including platinum-based doublet chemotherapy, molecular agents targeting oncogene-addicted NSCLC, and immunotherapy in the form of checkpoint inhibitors, have led to improved control of micro-metastatic disease and extended survival sparking newfound interest in combining these agents with ablative local therapies to provide additive, and in the case of radiation and immunotherapy, potentially synergistic, effects in order to further improve progression-free and overall survival. Currently, despite the tantalizing potential associated with aggressive local therapy in the setting of oligometastatic NSCLC, well-designed prospective randomized controlled trials sufficiently powered to detect and measure the possible added benefit afforded by this approach are

  18. Chemotherapy disruption of efficient radiotherapy

    International Nuclear Information System (INIS)

    Nervi, C.; Friedman, M.

    1974-01-01

    Studies on the use of chemotherapy in combination with radiotherapy are reviewed. Some topics discussed are: indications for the use of combined chemotherapy and radiotherapy; improvement of the therapeutic ratio following the use of methotrexate; advantages of preirradiation and postirradiation chemotherapy; side effects following simultaneous chemotherapy and radiotherapy; and effects of chemotherapy on cure rate of radiosensitive and radioresistant tumors. (U.S.)

  19. Radiotherapy of pineal tumors

    International Nuclear Information System (INIS)

    Danoff, B.; Sheline, G.E.

    1984-01-01

    Radiotherapy has universally been used in the treatment of pineal tumors and suprasellar germinomas. Recently however, major technical advances related to the use of the operating microscope and development of microsurgical techniques have prompted a renewed interest in the direct surgical approach for biopsy and/or excision. This interest has resulted in a controversy regarding the role of surgery prior to radiotherapy. Because of the heterogeneity of tumors occurring in the pineal region (i.e., germ cell tumors, pineal parenchymal tumors, glial tumors, and cysts) and their differing biological behavior, controversy also surrounds aspects of radiotherapy such as: the optimal radiation dose, the volume to be irradiated, and indications for prophylactic spinal irradiation. A review of the available data is presented in an attempt to answer these questions

  20. Cancer research and radiotherapy

    International Nuclear Information System (INIS)

    Matsuzawa, Taiju

    1978-01-01

    An actual condition of cancer, and the basis and a future view of radiotherapy were described by adding generally established biological and biochemical knowledge to the author's research. It was described that the relapse of cancer after irradiation was induced from outside of cancerous mass, and the nature of relapsed cancerous cells group was also stated. The histological structure of cancer from a view of cell movement and radioresistant cancerous cells group were described. The differentiation of cancerous cells were described, and a study of inhibition of cancer by redifferentiation was considered. It is important to grasp characteristics and a limit of radiotherapy for cancer, to systematize and materialize reasonable therapy which uses drug and immunotherapy together with surgery, and to use radiotherapy reasonably together with redifferentiation therapy of cancerous cells by extracting characteristics and a limit of radiationtherapy from an actual condition of cancer. (Serizawa, K.)

  1. Radiotherapy equipment and departments in the European countries

    DEFF Research Database (Denmark)

    Grau, Cai; Defourny, Noémie; Malicki, Julian

    2014-01-01

    BACKGROUND: Documenting the distribution of radiotherapy departments and the availability of radiotherapy equipment in the European countries is an important part of HERO - the ESTRO Health Economics in Radiation Oncology project. HERO has the overall aim to develop a knowledge base...... of the provision of radiotherapy in Europe and build a model for health economic evaluation of radiation treatments at the European level. The aim of the current report is to describe the distribution of radiotherapy equipment in European countries. METHODS: An 84-item questionnaire was sent out to European...... countries, principally through their national societies. The current report includes a detailed analysis of radiotherapy departments and equipment (questionnaire items 26-29), analyzed in relation to the annual number of treatment courses and the socio-economic status of the countries. The analysis is based...

  2. PET/CT Based Dose Planning in Radiotherapy

    DEFF Research Database (Denmark)

    Berthelsen, Anne Kiil; Jakobsen, Annika Loft; Sapru, Wendy

    2011-01-01

    radiotherapy planning with PET/CT prior to the treatment. The PET/CT, including the radiotherapy planning process as well as the radiotherapy process, is outlined in detail. The demanding collaboration between mould technicians, nuclear medicine physicians and technologists, radiologists and radiology......This mini-review describes how to perform PET/CT based radiotherapy dose planning and the advantages and possibilities obtained with the technique for radiation therapy. Our own experience since 2002 is briefly summarized from more than 2,500 patients with various malignant diseases undergoing...... technologists, radiation oncologists, physicists, and dosimetrists is emphasized. We strongly believe that PET/CT based radiotherapy planning will improve the therapeutic output in terms of target definition and non-target avoidance and will play an important role in future therapeutic interventions in many...

  3. Children Undergoing Radiotherapy: Swedish Parents’ Experiences and Suggestions for Improvement

    Science.gov (United States)

    Mullaney, Tara; Nilsson, Kristina; Wickart-Johansson, Gun; Svärd, Anna-Maja; Nyholm, Tufve; Lindh, Jack; Lindh, Viveca

    2015-01-01

    Approximately 300 children, from 0 to 18 years old, are diagnosed with cancer in Sweden every year. Of these children, 80–90 of them undergo radiotherapy treatment for their cancer. Although radiotherapy is an encounter with advanced technology, few studies have investigated the child’s and the parent’s view of the procedure. As part of an ongoing multicenter study aimed to improve patient preparation and the care environment in pediatric radiotherapy, this article reports the findings from interviews with parents at baseline. The aim of the present study was twofold: to describe parents’ experience when their child undergoes radiotherapy treatment, and to report parents’ suggestions for improvements during radiotherapy for their children. Sixteen mothers and sixteen fathers of children between 2–16 years old with various cancer diagnoses were interviewed. Data were analyzed using content analysis. The findings showed that cancer and treatment turns people’s lives upside down, affecting the entire family. Further, the parents experience the child’s suffering and must cope with intense feelings. Radiotherapy treatment includes preparation by skilled and empathetic staff. The parents gradually find that they can deal with the process; and lastly, parents have suggestions for improvements during the radiotherapy treatment. An overarching theme emerged: that despair gradually turns to a sense of security, with a sustained focus on and close interaction with the child. In conclusion, an extreme burden was experienced around the start of radiotherapy, though parents gradually coped with the process. PMID:26509449

  4. Validating Fricke dosimetry for the measurement of absorbed dose to water for HDR 192Ir brachytherapy: a comparison between primary standards of the LCR, Brazil, and the NRC, Canada

    Science.gov (United States)

    Salata, Camila; Gazineu David, Mariano; de Almeida, Carlos Eduardo; El Gamal, Islam; Cojocaru, Claudiu; Mainegra-Hing, Ernesto; McEwen, Malcom

    2018-04-01

    Two Fricke-based absorbed dose to water standards for HDR Ir-192 dosimetry, developed independently by the LCR in Brazil and the NRC in Canada have been compared. The agreement in the determination of the dose rate from a HDR Ir-192 source at 1 cm in a water phantom was found to be within the k  =  1 combined measurement uncertainties of the two standards: D NRC/D LCR  =  1.011, standard uncertainty  =  2.2%. The dose-based standards also agreed within the uncertainties with the manufacturer’s stated dose rate value, which is traceable to a national standard of air kerma. A number of possible influence quantities were investigated, including the specific method for producing the ferrous-sulphate Fricke solution, the geometry of the holder, and the Monte Carlo code used to determine correction factors. The comparison highlighted the lack of data on the determination of G(Fe3+) in this energy range and the possibilities for further development of the holders used to contain the Fricke solution. The comparison also confirmed the suitability of Fricke dosimetry for Ir-192 primary standard dose rate determinations at therapy dose levels.

  5. Magnetic resonance imaging in radiotherapy treatment planning

    NARCIS (Netherlands)

    Moerland, Marinus Adriaan

    1996-01-01

    From its inception in the early 1970's up to the present, magnetic resonance imaging (MRI) has evolved into a sophisticated technique, which has aroused considerable interest in var- ious subelds of medicine including radiotherapy. MRI is capable of imaging in any plane and does not use ionizing

  6. Quality assurance for image-guided radiotherapy

    International Nuclear Information System (INIS)

    Marinello, Ginette

    2008-01-01

    The topics discussed include, among others, the following: Quality assurance program; Image guided radiotherapy; Commissioning and quality assurance; Check of agreement between visual and displayed scales; quality controls: electronic portal imaging device (EPID), MV-kV and kV-kV, cone-beam CT (CBCT), patient doses. (P.A.)

  7. Clinical results in heavy particle radiotherapy

    International Nuclear Information System (INIS)

    Castro, J.R.; Quivey, J.M.; Saunders, W.M.; Woodruff, K.H.; Chen, G.T.Y.; Lyman, J.T.; Pitluck, S.; Tobias, C.A.; Walton, R.E.; Peters, T.C.

    1980-01-01

    The chapter presents an overview of the use of heavy particles in human cancer radiotherapy. The biophysical characteristics and rationale for using heavy charged particle therapy are explored. The clinical experience with carbon, neon, argon and helium are summarized for various types of tumors including carcinomas of the uterine cervix and lung, skin melanomas and metastatic sarcomas. No obvious normal tissue complications have appeared

  8. Radiotherapy in breast cancer and its prognosis

    International Nuclear Information System (INIS)

    Mitter, Mihir

    1980-01-01

    Various aspects of breast cancer are discussed. These include clinical staging, histological grading, site of growth, frequency and lactation, immunological response and prognosis, and survival of untreated cases. Importance of early detection is emphasised and prognosis after radiotherapy alone or in combination with surgery is briefly discussed. (M.G.B.)

  9. Radiotherapy for the medulloblastoma

    International Nuclear Information System (INIS)

    Gose, Kyuhei; Imajo, Yoshinari; Imanaka, Kazufumi

    1983-01-01

    Eighteen patients with medulloblastoma, treated between 1972 and 1981, at Kobe University School of Medicine, were retrospectively studied. Of those completing post operative irradiation, 50% have survived for 2 years, 15% for 5 years and mean survival periods was 22.2 months. 13 out of 18 patients developed local recurrence and spinal dissemination. The mean time from the initial radiotherapy to recurrence was 8.5 months. It was suggested that posterior fossa should recieve 5,000 rad, the spine should 2,000 rad and recurrences should be treated by the combination of radiotherapy and chemotherapy. (author)

  10. Arterial disease after radiotherapy

    International Nuclear Information System (INIS)

    Bigot, J.M.; Mathieu, D.; Reizine, D.

    1983-01-01

    Disease of the large arterial vessels is a relatively unknown complication of radiotherapy. However, it should be considered in the same manner as the other complications of irradiation when a tumour recurrence is suspected. The experimental studies of Kirkpatrick and Konings, demonstrating the synergy between irradiation and hypercholesterolemia in the precocity and gravity of vascular complications are recalled. The different localisations reported in the litterature are discussed: coronary, pulmonary, thoracic aorta, supra aortic, renal, digestive and ilio-femoral arteries. Finally, the difficulty of diagnosis of post-radiotherapy without clinical, radiological or anatomopathological confirmation, is underlined [fr

  11. Second cancers following radiotherapy

    International Nuclear Information System (INIS)

    Tubiana, M.

    1983-01-01

    Published reports have shown that there is an increased incidence of second malignancies, particularly sarcomas, following high dose radiotherapy in cancer treatment. However, this increased risk is very small and is relatively negligeable when one considers the beneficial effects of radiotherapy in cancer treatment. This incidence of radiation induced cancer appears to be higher in certain groups of patients, such as children and patients with Hodgkin's disease. In view of scarcity of published data, controlled surveys remain necessary for the quantitative assessment of the cancer risk in various subgroups of irradited patients [fr

  12. Xerostomia induced by radiotherapy

    Directory of Open Access Journals (Sweden)

    Alimi D

    2015-08-01

    Full Text Available David Alimi Department of Anesthesiology, University of Pittsburgh Medical Center, Pittsburgh, PA, USAWe read with great interest the excellent review on xerostomia induced by radiotherapy, by Pinna et al.1 The authors should be congratulated for a very detailed review of the physiopathology, clinical symptoms, and therapeutic management of an extremely difficult condition. Although we agree that the use of anticholinergic medication represents treatment, it requires the patient to have residual salivary gland function. Unfortunately, it is well established that in most cases radiotherapy destroys most of the salivary gland and associated salivary secretions.     

  13. Acute genitourinary toxicity after high-dose-rate (HDR) brachytherapy combined with hypofractionated external-beam radiation therapy for localized prostate cancer: Correlation between the urethral dose in HDR brachytherapy and the severity of acute genitourinary toxicity

    International Nuclear Information System (INIS)

    Akimoto, Tetsuo; Ito, Kazuto; Saitoh, Jun-ichi; Noda, Shin-ei; Harashima, Koichi; Sakurai, Hideyuki; Nakayama, Yuko; Yamamoto, Takumi; Suzuki, Kazuhiro; Nakano, Takashi; Niibe, Hideo

    2005-01-01

    Purpose: Several investigations have revealed that the α/β ratio for prostate cancer is atypically low, and that hypofractionation or high-dose-rate (HDR) brachytherapy regimens using appropriate radiation doses may be expected to yield tumor control and late sequelae rates that are better or at least as favorable as those achieved with conventional radiation therapy. In this setting, we attempted treating localized prostate cancer patients with HDR brachytherapy combined with hypofractionated external beam radiation therapy (EBRT). The purpose of this study was to evaluate the feasibility of using this approach, with special emphasis on the relationship between the severity of acute genitourinary (GU) toxicity and the urethral dose calculated from the dose-volume histogram (DVH) of HDR brachytherapy. Methods and Materials: Between September 2000 and December 2003, 70 patients with localized prostate cancer were treated by iridium-192 HDR brachytherapy combined with hypofractionated EBRT at the Gunma University Hospital. Hypofractionated EBRT was administered in fraction doses of 3 Gy, three times per week; a total dose of 51 Gy was delivered to the prostate gland and the seminal vesicles using the four-field technique. No elective pelvic irradiation was performed. After the completion of EBRT, all the patients additionally received transrectal ultrasonography (TRUS)-guided HDR brachytherapy. The fraction size and the number of fractions in HDR brachytherapy were prospectively changed, whereas the total radiation dose for EBRT was fixed at 51 Gy. The fractionation in HDR brachytherapy was as follows: 5 Gy x 5, 7 Gy x 3, 9 Gy x 2, administered twice per day, although the biologic effective dose (BED) for HDR brachytherapy combined with EBRT, assuming that the α/β ratio is 3, was almost equal to 138 in each fractionation group. The planning target volume was defined as the prostate gland with 5-mm margin all around, and the planning was conducted based on

  14. Dosimetric measurements of an 192Ir HDR source with a diamond detector

    International Nuclear Information System (INIS)

    Rustgi, Surendra N.

    1996-01-01

    Purpose: To study the feasibility of using a diamond detector for the dosimetry of a high dose rate (HDR) 192 Ir source and to compare the measurement results with published data and calculations from a commercial treatment planning system. Materials and methods: The sensitive volume of the diamond detector consists of a disk of 0.26 mm thickness and 3 mm diameter. The detector was applied an external bias of +100 V and was preirradiated to a dose of 500 cGy to stabilize its response. The 192 Ir source from the Nucletron microSelectron unit has an active diameter of 0.6 mm and a length of 3.5 mm. Photon fluence anisotropy factors in air were measured at distances of 5 and 10 cm from two sources and compared with TLD measurements. Dose profiles and isodose distributions were measured at several distances from the source and compared with calculations from a Nucletron treatment planning system. These dose calculations in water use a point source approximation with the anisotropy factors independent of the radial distance from the source. Results: The photon fluence around the 192 Ir HDR source, measured with a diamond detector at distances of 5 and 10 cm from the source, is very anisotropic. Compared to the source transverse direction, the photon fluence intensity along the source axis reduces to approximately 60%. Measurements performed on two sources indicate that the photon anisotropy does not change with distance in air. Within experimental uncertainty, similar results were obtained with TLD rods and are in excellent agreement with published anisotropy factors 1 . Dose profiles, measured with the diamond detector in a water phantom, at distances of 1,2,3 and 5 cm from the source, are found to be in excellent agreement with the Nucletron planning system calculations. Similar excellent agreement is observed between the measured and calculated isodose curves in planes parallel to the source plane. Conclusion: The diamond detector has been demonstrated to be suitable

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

    International Nuclear Information System (INIS)

    Siauw, Timmy; Cunha, Adam; Berenson, Dmitry; Atamtürk, Alper; Hsu, I-Chow; Goldberg, Ken; Pouliot, Jean

    2012-01-01

    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, δ. The candidate needle set consisted of 5000 needles, and a range of δ 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 δ 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 or fewer

  16. 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.

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

    International Nuclear Information System (INIS)

    Poulin, Eric; Racine, Emmanuel; Beaulieu, Luc; Binnekamp, Dirk

    2015-01-01

    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 ® 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

  18. Patterns of radiotherapy practice for patients with squamous carcinoma of the uterine cervix. A patterns of care study

    International Nuclear Information System (INIS)

    Eifel, Patricia J.; Owen, Jean; Stouffer, Nicole O.; Hanks, Gerald E.

    1997-01-01

    Purpose: To determine the impact of evolving technology and the influence of published findings from retrospective and prospective studies on the patterns of radiotherapy practice for patients with carcinoma of the uterine cervix. Materials and Methods: 66 institutions were randomly selected for the National Survey (NS) from a master list of all radiation facilities in the United States, proportionally stratified according to practice type. To study the potential influence of patient ethnicity on practice patterns, 12 additional facilities were selected for a Minority-Rich Survey (MRS) from a list of institutions that reported a high proportion of minority patients in their census. Each facility submitted a list of patients treated in 1992-94 with radiation for squamous carcinoma of the cervix. Patients who had clinical evidence of distance metastases or who were treated with initial hysterectomy were excluded. Patients were randomly selected from each institution for review. A total of 601 patients' records were reviewed in the treating institution by one of two trained research associates. Information was recorded about patients' characteristics, diagnostic evaluation, tumor extent, treatment approach, and radiotherapy techniques. Results: Of 601 patients, 31%, 40%, 24% and 4% had FIGO Stage I, II, III, or IV disease, respectively. 79% of women had a Karnofsky status ≥90 and 76% had a pre-treatment Hgb ≥10. Black women tended to have lower hemoglobin levels and a poorer performance status than Hispanic or non-Hispanic white patients although the distribution of tumors according to FIGO stage was similar for women of different ethnic groups. Diagnostic work-up included a CT scan in (411(516)) patients for whom information was available (80%). Of these, 61 (15%) were interpreted as showing evidence of nodal metastasis in either the abdomen or pelvis. Lymphangiogram or MRI were obtained in only 4% and 5% of patients, respectively. 104 patients had surgical

  19. 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

  20. 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

  1. Erythropoietin and radiotherapy; Erythropoietine et radiotherapie

    Energy Technology Data Exchange (ETDEWEB)

    Le Fur, E.; Albarghach, M.N.; Pradier, O. [CHU de Morvan, Dept. de radiotherapie, 29 - Brest (France)

    2010-01-15

    Erythropoietin (E.P.O.) is a glycoprotein hormone. This hormone is a growth factor for red blood cells precursors in the bone marrow. The decrease of oxygen partial pressure, a reduced number of erythrocytes caused by bleeding or excessive destruction, or increased tissues oxygen requirements lead to increased secretion of E.P.O.. Its action takes place on bone marrow erythroblastic cells through specific receptors. E.P.O. stimulates the proliferation of red cell precursors stem cells in the bone marrow, thus increasing their production in one to two weeks. The effectiveness of E.P.O. at increasing haemoglobin and improving patients quality of life has been demonstrated by several studies. However, its use in radiotherapy remains controversial. While tumour hypoxia caused by anaemia is a factor of radio resistance and thus a source of local failure, tumour expression of E.P.O. receptors presents a significant risk for tumour progression and neo-angiogenesis, which would be increased during the administration of E.P.O.. The purpose of this article is to answer the question: is there a place for E.P.O. in combination with radiotherapy in the management of cancer?

  2. Fractionated stereotactic radiotherapy for craniopharyngiomas

    International Nuclear Information System (INIS)

    Schulz-Ertner, Daniela; Frank, Claudia; Herfarth, Klaus K.; Rhein, Bernhard; Wannenmacher, Michael; Debus, Juergen

    2002-01-01

    Purpose: To investigate outcome and toxicity after fractionated stereotactic radiation therapy (FSRT) in patients with craniopharyngiomas. Methods and Materials: Twenty-six patients with craniopharyngiomas were treated with FSRT between May 1989 and February 2001. Median age was 33.5 years (range: 5-57 years). Nine patients received FSRT after surgery as primary treatment, and 17 patients were irradiated for recurrent tumor or progressive growth after initial surgery. Median target dose was 52.2 Gy (range: 50.0-57.6 Gy) with conventional fractionation. Follow-up included MRI and neurologic, ophthalmologic, and endocrinologic examinations. Results: The median follow-up was 43 months (range: 7-143 months). The actuarial local control rate and actuarial overall survival rates were 100% and 100%, respectively, at 5 years and 100% and 83%, respectively, at 10 years. Four patients showed complete response, 14 patients showed partial response, and 8 patients remained stable. In 5 patients, vision improved after radiation therapy. Acute toxicity was mild. One patient required cyst drainage 3 months after radiotherapy. Late toxicity after radiotherapy included impairment of hormone function in 3 out of 18 patients at risk. We did not observe any vision impairment, radionecrosis, or secondary malignancies. Conclusions: FSRT is effective and safe in the treatment of cystic craniopharyngiomas. Toxicity is extremely low using this conformal technique

  3. Analysis of the efficacy and safety of conventional radiotherapy of chest wall and clavicular field and three-dimensional conformal radiotherapy in patients after modified radical mastectomy

    Directory of Open Access Journals (Sweden)

    Song-Lin Wang

    2017-04-01

    Full Text Available Objective: To explore the efficacy and safety of conventional radiotherapy of chest wall and clavicular field and three-dimensional conformal radiotherapy in patients after modified radical mastectomy. Methods: A total of 84 patients who were admitted in our hospital after modified radical mastectomy were included in the study and divided into the conventional radiotherapy group (n=42 and the three-dimensional conformal radiotherapy group (n=42 according to different radiotherapy methods. The patients in the conventional radiotherapy group were given conventional radiotherapy of chest wall and clavicular field, while the patients in the three-dimensional conformal radiotherapy group were given three-dimensional conformal radiotherapy. The serum tumor markers and peripheral blood T lymphocyte subsets 6-8 weeks after treatment in the two groups were detected. The clinical efficacy, and toxic and side effects in the two groups were evaluated. Results: The serum CA15-3, CA125, CEA, and CK19 levels after treatment in the two groups were significantly reduced when compared with before treatment, CD3 +,CD4 +, and CD4 +/CD8 + were significantly elevated, while CD8 + was significantly reduced when compared with before treatment, but the comparison of the above indicators between the two groups was not statistically significant. The occurrence rate of radioactive skin damage and pneumonia after treatment in the conventional radiotherapy group was significantly higher than that in the three-dimensional conformal radiotherapy group. Conclusions: The two kinds of radiotherapy schemes have an equal efficacy, but the toxic and side effects of three-dimensional conformal radiotherapy are significantly lower than those by the conventional radiotherapy, with a certain advantage.

  4. Clinical efficacy of radiotherapy combined with sodium glycididazole ...

    African Journals Online (AJOL)

    treatment group (treated with radiotherapy and sodium glycididazole) and a control group (treated with ... Side effects in both groups included alopecia, headache, nausea, vomiting and ... hypoxic cells in a solid carcinoma to low linear ...

  5. Evolution of radiotherapy and chemotherapy practice in malignant gliomas

    Directory of Open Access Journals (Sweden)

    Anusheel Munshi

    2013-01-01

    Full Text Available Malignant astrocytomas of the brain carry a poor prognosis. This article traces the evolution of radiotherapy and chemotherapy practice including the development of concurrent chemo-radiation schedules in the context of these tumors.

  6. Multileaf collimator in radiotherapy

    International Nuclear Information System (INIS)

    Jeraj, M.; Robar, V.

    2004-01-01

    Background. Basic goal of radiotherapy treatment is the irradiation of a target volume while minimizing the amount of radiation absorbed in healthy tissue. Shaping the beam is an important way of minimizing the absorbed dose in healthy tissue and critical structures. Conventional collimator jaws are used for shaping a rectangular treatment field; but, as usually treatment volume is not rectangular, additional shaping is required. On a linear accelerator, lead blocks or individually made Cerroben TM blocks are attached onto the treatment head under standard collimating system. Another option is the use of multileaf collimator (MLC). Conclusions. Multileaf collimator is becoming the main tool for beam shaping on the linear accelerator. It is a simple and useful system in the preparation and performance of radiotherapy treatment. Multileaf collimators are reliable, as their manufacturers developed various mechanisms for their precision, control and reliability, together with reduction of leakage and transmission of radiation between and through the leaves. Multileaf collimator is known today as a very useful clinical system for simple field shaping, but its use is getting even more important in dynamic radiotherapy, with the leaves moving during irradiation. This enables a precise dose delivery on any part of a treated volume. Intensity modulated radiotherapy (IMRT), the therapy of the future, is based on the dynamic use of MLC. (author)

  7. [Radiotherapy of oropharynx carcinoma].

    Science.gov (United States)

    Servagi Vernat, S; Tochet, F; Vieillevigne, L; Pointreau, Y; Maingon, P; Giraud, P

    2016-09-01

    Indication, doses, technique of radiotherapy and concomitant chemotherapy for oropharynx carcinoma are presented. The recommendations for delineation of the target volumes and organs at risk are detailed. Copyright © 2016 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.

  8. Quality indicators in radiotherapy

    International Nuclear Information System (INIS)

    Cionini, Luca; Gardani, Gianstefano; Gabriele, Pietro; Magri, Secondo; Morosini, Pier Luigi; Rosi, Antonella; Viti, Vincenza

    2007-01-01

    Background and purpose: There is a widespread and increasing tendency to develop hospital performance indicators in the field of accreditation/certification systems and quality benchmarking. A study has been undertaken to develop a set of performance indicators for a typical radiotherapy Centre and to evaluate their ability to provide a continuous quality improvement. Materials and methods: A working group consisting of radiation oncologists, medical physicists and radiation technologists under the coordination of experts in health technology assessment has elaborated a set of general indicators able to monitor performances and the quality level of a typical radiotherapy Centre. The work has been carried out through four steps: a preliminary set of indicators was selected; data on these indicators were collected in a number of Italian radiotherapy Centres and medical physics Services; problems in collection and analysis of data were discussed; a final set of indicators was developed. Results: A final set of 13 indicators is here presented. They concern general structural and/or operational features, health physics activities and accuracy and technical complexity of the treatment. Conclusions: The indicators tested in a few Italian Centres of radiotherapy and medical physics Services are now ready to be utilized by a larger community

  9. Bowel disease after radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Schofield, P.F.; Holden, D.; Carr, N.D. (Christie Hospital and Holt Radium Inst., Manchester (UK))

    1983-06-01

    The clinical presentation, operative findings and outcome in 40 patients who required surgery for bowel disease after radiotherapy are presented. The type of presentation varied according to the time after radiotherapy. In the first month, many patients had a proctitis but none required surgery. Five patients were operated on within one month, 2 for radiation-induced acute ileitis and 3 for exacerbations of pre-existing disease (diverticular disease 2, ulcerative colitis 1). The commonest time of presentation was between 3 and 18 months after radiotherapy, when 20 patients needed surgery for bowel disease caused by radiation-induced local ischaemia. Twelve of these patients had chronic perforation, 6 had severe rectal bleeding and 2 had painful anorectal ulceration. Fifteen patients presented between 2 and 24 years after radiotherapy, usually with incomplete intestinal obstruction due to a fibrous stricture, but 2 patients had rectal carcinoma. Wide resection of the involved bowel was the principal method of treatment but any anastomosis was protected by a proximal defunctioning stoma. There was no operative mortality but 10 patients have died subsequently. The danger of dismissing these patients as having incurable malignancy is stressed because, although the condition is infrequent, it is usually amenable to adequate surgery.

  10. Radiotherapy of breast fibrosis

    International Nuclear Information System (INIS)

    Heibel, J.H.

    1979-01-01

    In a retrospective study radiotherapy of breast fibrosis in hormone-treated men with histologically confirmed prostate carcinoma was examined. 10 patients had received hormones even before irradiation, 113 obtained hormone administration only after irradiation. The objective size of the glandular body and the overall size of the breast were measured with a special method developed by the author. 46 patients indicated complaints. With hypertrophic mamma and hypertrophic mamilla in 67 examined patients, 127 different symptoms resulted in total. Four patients of the group who had obtained hormones before irradiation, suffered from subjective symptoms. It resulted that radiotherapy of breast fibrosis carried out during hormone treatment is no gynecomastia prophylaxis, that already existent mamma hypertrophies are irreversible, but that existent sensations were notably reduced within 6 months after irradiation therapy. These results indicate the necessity of a radiotherapy of the mamma fibrosis before the hormone treatment is begun. Particularly in cases of higher operative risks, also the possibility of preferring radiotherapy to mastectomy should be fully utilized, in view of adequate or even better therapeutic results. (orig./MG) [de

  11. Gamma apparatuses for radiotherapy

    International Nuclear Information System (INIS)

    Sul'kin, A.G.

    1986-01-01

    Scientific and technical achievements in development and application of gamma therapeutic apparatuses for external and intracavity irradiations are generalized. Radiation-physical parameters of apparatuses providing usability of progressive methods in radiotherapy of onclogical patients are given. Optimization of main apparatus elements, ensurance of its operation reliability, reduction of errors of irradiation plan reproduction are considered. Attention is paid to radiation safety

  12. X-ray radiotherapy

    International Nuclear Information System (INIS)

    Tronc, D.

    1995-01-01

    Full text: The most common form of radio therapy is X-ray therapy, where a beam of photons or their parent electrons break down hydrogen bonds within the body's cells and remove certain DNA information necessary for cell multiplication. This process can eradicate malignant cells leading to complete recovery, to the remission of some cancers, or at least to a degree of pain relief. The radiotherapy instrument is usually an electron linac, and the electrons are used either directly in 'electrotherapy' for some 10% of patients, or the electrons bombard a conversion target creating a broad beam of high energy photons or 'penetration X-rays'. The simplest machine consists of several accelerating sections at around 3 GHz, accelerating electrons to 6 MeV; a cooled tungsten target is used to produce a 4 Gray/min X-ray field which can be collimated into a rectangular shape at the patient position. This tiny linac is mounted inside a rotating isocentric gantry above the patient who must remain perfectly still. Several convergent beams can also be used to increase the delivered dose. More sophisticated accelerators operate at up to 18 MeV to increase penetration depths and decrease skin exposure. Alternatively, electrotherapy can be used with different energies for lower and variable penetration depths - approximately 0.5 cm per MeV. In this way surface tissue may be treated without affecting deeper and more critical anatomical regions. This type of linac, 1 to 2 metres long, is mounted parallel to the patient with a bending magnet to direct the beam to the radiotherapy system, which includes the target, thick movable collimator jaws, a beam field equalizer, dose rate and optical field simulation and energy controls. There are over 2000 acceleratorbased X-ray treatment units worldwide. Western countries have up to two units per million population, whereas in developing countries such as Bangladesh, the density is only one per 100 million. Several

  13. HDR-investigations of check valve closure and resultant water hammer effects

    International Nuclear Information System (INIS)

    Scholl, K.D.

    1983-01-01

    The presented investigations are based on the Loss of Coolant Accident (LOCA). They concentrate on the first blowdown phase after pipe break of a feedwater line. The effect of such a break is moderated by quick closing check valves, by which the loss of coolant water is reduced and optimal post accident conditions are obtained. Unfortunately the closure of the valve can cause high pressure peaks (water hammer effects) in the feedwater system which potentially could produce safety relevant secondary damage. The system loading by these effects has been analysed. The HDR-Investigation-results led to an improvement of the feedwater system safety by verifying damping measures of quick closing check valves. Pressure peaks obtained with undamped valves in the range of 300 bars, are reduced to zero or a few bars above the normal operation pressure in feedwater systems. For the analytical simulation of valve closure the following dominant acting forces are identified: the blowdown flow resistance of the valve cone and the damping pistong force. The analytical description and quantification of the forces depends on blowdown flow and valve friction parameters. These have been evaluated and are presented for practical use. (orig.)

  14. 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)

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

    International Nuclear Information System (INIS)

    Reyes, E.; Sosa, M. A.; Gil V, A.; Monzon, E.

    2015-10-01

    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)

  16. An in vivo investigative protocol for HDR prostate brachytherapy using urethral and rectal thermoluminescence dosimetry

    International Nuclear Information System (INIS)

    Toye, Warren; Das, Ram; Kron, Tomas; Franich, Rick; Johnston, Peter; Duchesne, Gillian

    2009-01-01

    Purpose: To develop an in vivo dosimetry based investigative action level relevant for a corrective protocol for HDR brachytherapy boost treatment. Methods and materials: The dose delivered to points within the urethra and rectum was measured using TLD in vivo dosimetry in 56 patients. Comparisons between the urethral and rectal measurements and TPS calculations showed differences, which are related to the relative position of the implant and TLD trains, and allowed shifts of implant position relative to the prostate to be estimated. Results and conclusions: Analysis of rectal dose measurements is consistent with implant movement, which was previously only identified with the urethral data. Shift corrected doses were compared with results from the TPS. Comparison of peak doses to the urethra and rectum has been assessed against the proposed corrective protocol to limit overdosing these critical structures. An initial investigative level of 20% difference between measured and TPS peak dose was established, which corresponds to 1/3 of patients which was practical for the caseload. These patients were assessed resulting in corrective action being applied for one patient. Multiple triggering for selective investigative action is outlined. The use of a single in vivo measurement in the first fraction optimizes patient benefit at acceptable cost.

  17. Intraoperative HDR brachytherapy for rectal cancer using a flexible intraoperative template: standard plans versus