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Sample records for radiotherapy helical tomotherapy

  1. Adaptive radiotherapy using helical tomotherapy system

    International Nuclear Information System (INIS)

    Jeswani, Sam; Ruchala, Kenneth; Olivera, Gustavo; Mackie, T.R.

    2008-01-01

    As commonly known in the field, adaptive radiation therapy (ART) is the use of feedback to modify a radiotherapy treatment. There are numerous ways in which this feedback can be received and used, and this presentation will discuss some of the implementations of ART being investigated with a helical TomoTherapy system

  2. Standard and Nonstandard Craniospinal Radiotherapy Using Helical TomoTherapy

    International Nuclear Information System (INIS)

    Parker, William; Brodeur, Marylene; Roberge, David; Freeman, Carolyn

    2010-01-01

    Purpose: To show the advantages of planning and delivering craniospinal radiotherapy with helical TomoTherapy (TomoTherapy Inc., Madison, WI) by presenting 4 cases treated at our institution. Methods and Materials: We first present a standard case of craniospinal irradiation in a patient with recurrent myxopapillary ependymoma (MPE) and follow this with 2 cases requiring differential dosing to multiple target volumes. One of these, a patient with recurrent medulloblastoma, required a lower dose to be delivered to the posterior fossa because the patient had been previously irradiated to the full dose, and the other required concurrent boosts to leptomeningeal metastases as part of his treatment for newly diagnosed MPE. The final case presented is a patient with pronounced scoliosis who required spinal irradiation for recurrent MPE. Results: The four cases presented were planned and treated successfully with Helical Tomotherapy. Conclusions: Helical TomoTherapy delivers continuous arc-based intensity-modulated radiotherapy that gives high conformality and excellent dose homogeneity for the target volumes. Increased healthy tissue sparing is achieved at higher doses albeit at the expense of larger volumes of tissue receiving lower doses. Helical TomoTherapy allows for differential dosing of multiple targets, resulting in very elegant dose distributions. Daily megavoltage computed tomography imaging allows for precision of patient positioning, permitting a reduction in planning margins and increased healthy tissue sparing in comparison with standard techniques.

  3. [Technique of complex mammary irradiation: Mono-isocentric 3D conformational radiotherapy and helical tomotherapy].

    Science.gov (United States)

    Vandendorpe, B; Guilbert, P; Champagne, C; Antoni, T; Nguyen, T D; Gaillot-Petit, N; Servagi Vernat, S

    2017-12-01

    To evaluate the dosimetric contribution of helical tomotherapy for breast cancers compared with conformal radiotherapy in mono-isocentric technique. For 23 patients, the dosimetric results in mono-isocentric 3D conformational radiotherapy did not satisfy the constraints either of target volumes nor organs at risk. A prospective dosimetric comparison between mono-isocentric 3D conformational radiotherapy and helical tomotherapy was therefore carried out. The use of helical tomotherapy showed a benefit in these 23 patients, with either an improvement in the conformity index or homogeneity, but with an increase in low doses. Of the 23 patients, two had pectus excavatum, five had past thoracic irradiation and two required bilateral irradiation. The other 14 patients had a combination of morphology and/or indication of lymph node irradiation. For these patients, helical tomotherapy was therefore preferred to mono-isocentric 3D conformational radiotherapy. Tomotherapy appears to provide better homogeneity and tumour coverage. This technique of irradiation may be justified in the case of morphological situations such as pectus exavatum and in complex clinical situations. In other cases, conformal radiotherapy in mono-isocentric technique remains to be favoured. Copyright © 2017 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.

  4. Helical Tomotherapy Quality Assurance

    International Nuclear Information System (INIS)

    Balog, John; Soisson, Emilie

    2008-01-01

    Helical tomotherapy uses a dynamic delivery in which the gantry, treatment couch, and multileaf collimator leaves are all in motion during treatment. This results in highly conformal radiotherapy, but the complexity of the delivery is partially hidden from the end-user because of the extensive integration and automation of the tomotherapy control systems. This presents a challenge to the medical physicist who is expected to be both a system user and an expert, capable of verifying relevant aspects of treatment delivery. A related issue is that a clinical tomotherapy planning system arrives at a customer's site already commissioned by the manufacturer, not by the clinical physicist. The clinical physicist and the manufacturer's representative verify the commissioning at the customer site before acceptance. Theoretically, treatment could begin immediately after acceptance. However, the clinical physicist is responsible for the safe and proper use of the machine. In addition, the therapists and radiation oncologists need to understand the important machine characteristics before treatment can proceed. Typically, treatment begins about 2 weeks after acceptance. This report presents an overview of the tomotherapy system. Helical tomotherapy has unique dosimetry characteristics, and some of those features are emphasized. The integrated treatment planning, delivery, and patient-plan quality assurance process is described. A quality assurance protocol is proposed, with an emphasis on what a clinical medical physicist could and should check. Additionally, aspects of a tomotherapy quality assurance program that could be checked automatically and remotely because of its inherent imaging system and integrated database are discussed

  5. Stereotactic Image-Guided Intensity Modulated Radiotherapy Using the HI-ART II Helical Tomotherapy System

    International Nuclear Information System (INIS)

    Holmes, Timothy W.; Hudes, Richard; Dziuba, Sylwester; Kazi, Abdul; Hall, Mark; Dawson, Dana

    2008-01-01

    The highly integrated adaptive radiation therapy (HI-ART II) helical tomotherapy unit is a new radiotherapy machine designed to achieve highly precise and accurate treatments at all body sites. The precision and accuracy of the HI-ART II is similar to that provided by stereotactic radiosurgery systems, hence the historical distinction between external beam radiotherapy and stereotactic procedures based on differing precision requirements is removed for this device. The objectives of this work are: (1) to describe stereotactic helical tomotherapy processes (SRS, SBRT); (2) to show that the precision and accuracy of the HI-ART meet the requirements defined for SRS and SBRT; and (3) to describe the clinical implementation of a stereotactic image-guided intensity modulated radiation therapy (IG-IMRT) system that incorporates optical motion management

  6. Postmastectomy radiotherapy with integrated scar boost using helical tomotherapy

    International Nuclear Information System (INIS)

    Rong Yi; Yadav, Poonam; Welsh, James S.; Fahner, Tasha; Paliwal, Bhudatt

    2012-01-01

    The purpose of this study was to evaluate helical tomotherapy dosimetry in postmastectomy patients undergoing treatment for chest wall and positive nodal regions with simultaneous integrated boost (SIB) in the scar region using strip bolus. Six postmastectomy patients were scanned with a 5-mm-thick strip bolus covering the scar planning target volume (PTV) plus 2-cm margin. For all 6 cases, the chest wall received a total cumulative dose of 49.3–50.4 Gy with daily fraction size of 1.7–2.0 Gy. Total dose to the scar PTV was prescribed to 58.0–60.2 Gy at 2.0–2.5 Gy per fraction. The supraclavicular PTV and mammary nodal PTV received 1.7–1.9 dose per fraction. Two plans (with and without bolus) were generated for all 6 cases. To generate no-bolus plans, strip bolus was contoured and overrode to air density before planning. The setup reproducibility and delivered dose accuracy were evaluated for all 6 cases. Dose-volume histograms were used to evaluate dose-volume coverage of targets and critical structures. We observed reduced air cavities with the strip bolus setup compared with what we normally see with the full bolus. The thermoluminescence dosimeters (TLD) in vivo dosimetry confirmed accurate dose delivery beneath the bolus. The verification plans performed on the first day megavoltage computed tomography (MVCT) image verified that the daily setup and overall dose delivery was within 2% accuracy compared with the planned dose. The hotspot of the scar PTV in no-bolus plans was 111.4% of the prescribed dose averaged over 6 cases compared with 106.6% with strip bolus. With a strip bolus only covering the postmastectomy scar region, we observed increased dose uniformity to the scar PTV, higher setup reproducibility, and accurate dose delivered beneath the bolus. This study demonstrates the feasibility of using a strip bolus over the scar using tomotherapy for SIB dosimetry in postmastectomy treatments.

  7. Treatment Planning for Pulsed Reduced Dose-Rate Radiotherapy in Helical Tomotherapy

    International Nuclear Information System (INIS)

    Rong Yi; Paliwal, Bhudatt; Howard, Steven P.; Welsh, James

    2011-01-01

    Purpose: Pulsed reduced dose-rate radiotherapy (PRDR) is a valuable method of reirradiation because of its potential to reduce late normal tissue toxicity while still yielding significant tumoricidal effect. A typical method using a conventional linear accelerator (linac) is to deliver a series of 20-cGy pulses separated by 3-min intervals to give an effective dose-rate of just under 7 cGy/min. Such a strategy is fraught with difficulties when attempted on a helical tomotherapy unit. We investigated various means to overcome this limitation. Methods and Materials: Phantom and patient cases were studied. Plans were generated with varying combinations of field width (FW), pitch, and modulation factor (MF) to administer 200 cGy per fraction to the planning target in eight subfractions, thereby mimicking the technique used on conventional linacs. Plans were compared using dose-volume histograms, homogeneity indices, conformation numbers, and treatment time. Plan delivery quality assurance was performed to assess deliverability. Results: It was observed that for helical tomotherapy, intrinsic limitations in leaf open time in the multileaf collimator deteriorate plan quality and deliverability substantially when attempting to deliver very low doses such as 20-40 cGy. The various permutations evaluated revealed that the combination of small FW (1.0 cm), small MF (1.3-1.5), and large pitch (∼0.86), along with the half-gantry-angle-blocked scheme, can generate clinically acceptable plans with acceptable delivery accuracy (±3%). Conclusion: Pulsed reduced dose-rate radiotherapy can be accurately delivered using helical tomotherapy for tumor reirradiation when the appropriate combination of FW, MF, and pitch is used.

  8. Dosimetric aspects of breast radiotherapy with three-dimensional and intensity-modulated radiotherapy helical tomotherapy planning modules

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    Yadav, Poonam [Department of Human Oncology, University of Wisconsin-Madison, Madison, WI (United States); Service of Radiation Therapy, University of Wisconsin Aspirus Cancer Center, Wisconsin Rapids, WI (United States); Yan, Yue, E-mail: yyan5@mdanderson.org [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX (United States); Ignatowski, Tasha [Service of Radiation Therapy, University of Wisconsin Aspirus Cancer Center, Wisconsin Rapids, WI (United States); Olson, Anna [Department of Human Oncology, University of Wisconsin-Madison, Madison, WI (United States); Service of Radiation Therapy, University of Wisconsin Aspirus Cancer Center, Wisconsin Rapids, WI (United States)

    2017-04-01

    In this work, we investigated the dosimetric differences between the intensity-modulated radiotherapy (IMRT) plans and the three-dimensional (3D) helical plans based on the TomoTherapy system. A total of 15 patients with supine setup were randomly selected from the data base. For patients with lumpectomy planning target volume (PTV), regional lymph nodes were also included as part of the target. For dose sparing, the significant differences between the helical IMRT and helical 3D were only found in the heart and contralateral breast. For the dose to the heart, helical IMRT reduced the maximum point dose by 6.98 Gy compared to the helical 3D plan (p = 0.01). For contralateral breast, the helical IMRT plans significantly reduced the maximum point dose by 5.6 Gy compared to the helical 3D plan. However, compared to the helical 3D plan, the helical IMRT plan increased the volume for lower dose (13.08% increase in V{sub 5} {sub Gy}, p = 0.01). In general, there are no significant differences in dose sparing between helical IMRT and helical 3D plans.

  9. Dosimetric aspects of breast radiotherapy with three-dimensional and intensity-modulated radiotherapy helical tomotherapy planning modules

    International Nuclear Information System (INIS)

    Yadav, Poonam; Yan, Yue; Ignatowski, Tasha; Olson, Anna

    2017-01-01

    In this work, we investigated the dosimetric differences between the intensity-modulated radiotherapy (IMRT) plans and the three-dimensional (3D) helical plans based on the TomoTherapy system. A total of 15 patients with supine setup were randomly selected from the data base. For patients with lumpectomy planning target volume (PTV), regional lymph nodes were also included as part of the target. For dose sparing, the significant differences between the helical IMRT and helical 3D were only found in the heart and contralateral breast. For the dose to the heart, helical IMRT reduced the maximum point dose by 6.98 Gy compared to the helical 3D plan (p = 0.01). For contralateral breast, the helical IMRT plans significantly reduced the maximum point dose by 5.6 Gy compared to the helical 3D plan. However, compared to the helical 3D plan, the helical IMRT plan increased the volume for lower dose (13.08% increase in V 5 Gy , p = 0.01). In general, there are no significant differences in dose sparing between helical IMRT and helical 3D plans.

  10. Radiotherapy for Adult Medulloblastoma: Evaluation of Helical Tomotherapy, Volumetric Intensity Modulated Arc Therapy, and Three-Dimensional Conformal Radiotherapy and the Results of Helical Tomotherapy Therapy

    Directory of Open Access Journals (Sweden)

    Sun Zong-wen

    2018-01-01

    Full Text Available Introduction. All adult medulloblastoma (AMB patients should be treated with craniospinal irradiation (CSI postoperatively. Because of the long irradiation range, multiple radiation fields must be designed for conventional radiotherapy technology. CSI can be completed in only one session with helical tomotherapy (HT. We evaluated the dose of HT, volumetric intensity modulated arc therapy (VMAT, and three-dimensional conformal radiotherapy (3D-CRT of AMB and the results of 5 cases of AMB treated with HT. Methods. Complete craniospinal and posterior cranial fossa irradiation with HT, VMAT, and 3D-CRT and dose evaluation were performed. And results of 5 cases of AMB treated with HT were evaluated. Results. A large volume of tissue was exposed to low dose radiation in the organs at risk (OAR, while a small volume was exposed to high dose radiation with HT. The conformity and uniformity of the targets were good with HT and VMAT, and the volume of targets exposed to high dose with VMAT was larger than that of HT. The uniformity of 3D-CRT was also good, but the dose conformity was poor. The main toxicity was hematologic toxicity, without 4th-degree bone marrow suppression. There was 3rd-degree inhibition in the white blood cells, hemoglobin, and platelets. The three female patients suffered menstrual disorders during the course of radiation. Two female patients with heavy menstruation suffered 3rd-degree anemia inhibition, and 2 patients suffered amenorrhea after radiotherapy. Although menstrual cycle was normal, the third patient was not pregnant. Conclusion. CSI with HT is convenient for clinical practice, and the side effects are mild. With good conformity and uniformity, VMAT can also be used for selection in CSI. For poor conformity, 3D-CRT should not be the priority selection for CSI. In female patients, the ovaries should be protected.

  11. Clinical benefits of new immobilization system for hypofractionated radiotherapy of intrahepatic hepatocellular carcinoma by helical tomotherapy

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    Hu, Yong; Zhou, Yong-Kang; Chen, Yi-Xing; Shi, Shi-Ming; Zeng, Zhao-Chong, E-mail: zeng.zhaochong@zs-hospital.sh.cn

    2017-04-01

    Objective: A comprehensive clinical evaluation was conducted, assessing the Body Pro-Lok immobilization and positioning system to facilitate hypofractionated radiotherapy of intrahepatic hepatocellular carcinoma (HCC), using helical tomotherapy to improve treatment precision. Methods: Clinical applications of the Body Pro-Lok system were investigated (as above) in terms of interfractional and intrafractional setup errors and compressive abdominal breath control. To assess interfractional setup errors, a total of 42 patients who were given 5 to 20 fractions of helical tomotherapy for intrahepatic HCC were analyzed. Overall, 15 patients were immobilized using simple vacuum cushion (group A), and the Body Pro-Lok system was used in 27 patients (group B), performing megavoltage computed tomography (MVCT) scans 196 times and 435 times, respectively. Pretreatment MVCT scans were registered to the planning kilovoltage computed tomography (KVCT) for error determination, and group comparisons were made. To establish intrafractional setup errors, 17 patients with intrahepatic HCC were selected at random for immobilization by Body Pro-Lok system, undergoing MVCT scans after helical tomotherapy every week. A total of 46 MVCT re-scans were analyzed for this purpose. In researching breath control, 12 patients, randomly selected, were immobilized by Body Pro-Lok system and subjected to 2-phase 4-dimensional CT (4DCT) scans, with compressive abdominal control or in freely breathing states, respectively. Respiratory-induced liver motion was then compared. Results: Mean interfractional setup errors were as follows: (1) group A: X, 2.97 ± 2.47 mm; Y, 4.85 ± 4.04 mm; and Z, 3.77 ± 3.21 mm; pitch, 0.66 ± 0.62°; roll, 1.09 ± 1.06°; and yaw, 0.85 ± 0.82°; and (2) group B: X, 2.23 ± 1.79 mm; Y, 4.10 ± 3.36 mm; and Z, 1.67 ± 1.91 mm; pitch, 0.45 ± 0.38°; roll, 0.77 ± 0.63°; and yaw, 0.52 ± 0.49°. Between-group differences were statistically significant in 6 directions (p

  12. Clinical benefits of new immobilization system for hypofractionated radiotherapy of intrahepatic hepatocellular carcinoma by helical tomotherapy

    International Nuclear Information System (INIS)

    Hu, Yong; Zhou, Yong-Kang; Chen, Yi-Xing; Shi, Shi-Ming; Zeng, Zhao-Chong

    2017-01-01

    Objective: A comprehensive clinical evaluation was conducted, assessing the Body Pro-Lok immobilization and positioning system to facilitate hypofractionated radiotherapy of intrahepatic hepatocellular carcinoma (HCC), using helical tomotherapy to improve treatment precision. Methods: Clinical applications of the Body Pro-Lok system were investigated (as above) in terms of interfractional and intrafractional setup errors and compressive abdominal breath control. To assess interfractional setup errors, a total of 42 patients who were given 5 to 20 fractions of helical tomotherapy for intrahepatic HCC were analyzed. Overall, 15 patients were immobilized using simple vacuum cushion (group A), and the Body Pro-Lok system was used in 27 patients (group B), performing megavoltage computed tomography (MVCT) scans 196 times and 435 times, respectively. Pretreatment MVCT scans were registered to the planning kilovoltage computed tomography (KVCT) for error determination, and group comparisons were made. To establish intrafractional setup errors, 17 patients with intrahepatic HCC were selected at random for immobilization by Body Pro-Lok system, undergoing MVCT scans after helical tomotherapy every week. A total of 46 MVCT re-scans were analyzed for this purpose. In researching breath control, 12 patients, randomly selected, were immobilized by Body Pro-Lok system and subjected to 2-phase 4-dimensional CT (4DCT) scans, with compressive abdominal control or in freely breathing states, respectively. Respiratory-induced liver motion was then compared. Results: Mean interfractional setup errors were as follows: (1) group A: X, 2.97 ± 2.47 mm; Y, 4.85 ± 4.04 mm; and Z, 3.77 ± 3.21 mm; pitch, 0.66 ± 0.62°; roll, 1.09 ± 1.06°; and yaw, 0.85 ± 0.82°; and (2) group B: X, 2.23 ± 1.79 mm; Y, 4.10 ± 3.36 mm; and Z, 1.67 ± 1.91 mm; pitch, 0.45 ± 0.38°; roll, 0.77 ± 0.63°; and yaw, 0.52 ± 0.49°. Between-group differences were statistically significant in 6 directions (p

  13. Radiation characteristics of helical tomotherapy

    International Nuclear Information System (INIS)

    Jeraj, Robert; Mackie, Thomas R.; Balog, John; Olivera, Gustavo; Pearson, Dave; Kapatoes, Jeff; Ruchala, Ken; Reckwerdt, Paul

    2004-01-01

    Helical tomotherapy is a dedicated intensity modulated radiation therapy (IMRT) system with on-board imaging capability (MVCT) and therefore differs from conventional treatment units. Different design goals resulted in some distinctive radiation field characteristics. The most significant differences in the design are the lack of flattening filter, increased shielding of the collimators, treatment and imaging operation modes and narrow fan beam delivery. Radiation characteristics of the helical tomotherapy system, sensitivity studies of various incident electron beam parameters and radiation safety analyses are presented here. It was determined that the photon beam energy spectrum of helical tomotherapy is similar to that of more conventional radiation treatment units. The two operational modes of the system result in different nominal energies of the incident electron beam with approximately 6 MeV and 3.5 MeV in the treatment and imaging modes, respectively. The off-axis mean energy dependence is much lower than in conventional radiotherapy units with less than 5% variation across the field, which is the consequence of the absent flattening filter. For the same reason the transverse profile exhibits the characteristic conical shape resulting in a 2-fold increase of the beam intensity in the center. The radiation leakage outside the field was found to be negligible at less than 0.05% because of the increased shielding of the collimators. At this level the in-field scattering is a dominant source of the radiation outside the field and thus a narrow field treatment does not result in the increased leakage. The sensitivity studies showed increased sensitivity on the incident electron position because of the narrow fan beam delivery and high sensitivity on the incident electron energy, as common to other treatment systems. All in all, it was determined that helical tomotherapy is a system with some unique radiation characteristics, which have been to a large extent

  14. Image Guided Hypofractionated Radiotherapy by Helical Tomotherapy for Prostate Carcinoma: Toxicity and Impact on Nadir PSA

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    Salvina Barra

    2014-01-01

    Full Text Available Aim. To evaluate the toxicity of a hypofractionated schedule for primary radiotherapy (RT of prostate cancer as well as the value of the nadir PSA (nPSA and time to nadir PSA (tnPSA as surrogate efficacy of treatment. Material and Methods. Eighty patients underwent hypofractionated schedule by Helical Tomotherapy (HT. A dose of 70.2 Gy was administered in 27 daily fractions of 2.6 Gy. Acute and late toxicities were graded on the RTOG/EORTC scales. The nPSA and the tnPSA for patients treated with exclusive RT were compared to an equal cohort of 20 patients treated with conventional fractionation and standard conformal radiotherapy. Results. Most of patients (83% did not develop acute gastrointestinal (GI toxicity and 50% did not present genitourinary (GU toxicity. After a median follow-up of 36 months only grade 1 of GU and GI was reported in 6 and 3 patients as late toxicity. Average tnPSA was 30 months. The median value of nPSA after exclusive RT with HT was 0.28 ng/mL and was significantly lower than the median nPSA (0.67 ng/mL of the conventionally treated cohort (P=0.02. Conclusions. Hypofractionated RT schedule with HT for prostate cancer treatment reports very low toxicity and reaches a low level of nPSA that might correlate with good outcomes.

  15. Dosimetric Comparison of Three Dimensional Conformal Radiation Radiotherapy and Helical Tomotherapy Partial Breast Cancer

    International Nuclear Information System (INIS)

    Kim, Dae Woong; Kim, Jong Won; Choi, Yun Kyeong; Kim, Jung Soo; Hwang, Jae Woong; Jeong, Kyeong Sik; Choi, Gye Suk

    2008-01-01

    The goal of radiation treatment is to deliver a prescribed radiation dose to the target volume accurately while minimizing dose to normal tissues. In this paper, we comparing the dose distribution between three dimensional conformal radiation radiotherapy (3D-CRT) and helical tomotherapy (TOMO) plan for partial breast cancer. Twenty patients were included in the study, and plans for two techniques were developed for each patient (left breast:10 patients, right breast:10 patients). For each patient 3D-CRT planning was using pinnacle planning system, inverse plan was made using Tomotherapy Hi-Art system and using the same targets and optimization goals. We comparing the Homogeneity index (HI), Conformity index (CI) and sparing of the organs at risk for dose-volume histogram. Whereas the HI, CI of TOMO was significantly better than the other, 3D-CRT was observed to have significantly poorer HI, CI. The percentage ipsilateral non-PTV breast volume that was delivered 50% of the prescribed dose was 3D-CRT (mean: 40.4%), TOMO (mean: 18.3%). The average ipsilateral lung volume percentage receiving 20% of the PD was 3D-CRT (mean: 4.8%), TOMO (mean: 14.2), concerning the average heart volume receiving 20% and 10% of the PD during treatment of left breast cancer 3D-CRT (mean: 1.6%, 3.0%), TOMO (mean: 9.7%, 26.3%) In summary, 3D-CRT and TOMO techniques were found to have acceptable PTV coverage in our study. However, in TOMO, high conformity to the PTV and effective breast tissue sparing was achieved at the expense of considerable dose exposure to the lung and heart.

  16. Comparing conformal, arc radiotherapy and helical tomotherapy in craniospinal irradiation planning.

    Science.gov (United States)

    Myers, Pamela A; Mavroidis, Panayiotis; Papanikolaou, Nikos; Stathakis, Sotirios

    2014-09-08

    Currently, radiotherapy treatment plan acceptance is based primarily on dosimetric performance measures. However, use of radiobiological analysis to assess benefit in terms of tumor control and harm in terms of injury to normal tissues can be advantageous. For pediatric craniospinal axis irradiation (CSI) patients, in particular, knowing the technique that will optimize the probabilities of benefit versus injury can lead to better long-term outcomes. Twenty-four CSI pediatric patients (median age 10) were retrospectively planned with three techniques: three-dimensional conformal radiation therapy (3D CRT), volumetric-modulated arc therapy (VMAT), and helical tomotherapy (HT). VMAT plans consisted of one superior and one inferior full arc, and tomotherapy plans were created using a 5.02cm field width and helical pitch of 0.287. Each plan was normalized to 95% of target volume (whole brain and spinal cord) receiving prescription dose 23.4Gy in 13 fractions. Using an in-house MATLAB code and DVH data from each plan, the three techniques were evaluated based on biologically effective uniform dose (D=), the complication-free tumor control probability (P+), and the width of the therapeutically beneficial range. Overall, 3D CRT and VMAT plans had similar values of D= (24.1 and 24.2 Gy), while HT had a D= slightly lower (23.6 Gy). The average values of the P+ index were 64.6, 67.4, and 56.6% for 3D CRT, VMAT, and HT plans, respectively, with the VMAT plans having a statistically significant increase in P+. Optimal values of D= were 28.4, 33.0, and 31.9 Gy for 3D CRT, VMAT, and HT plans, respectively. Although P+ values that correspond to the initial dose prescription were lower for HT, after optimizing the D= prescription level, the optimal P+ became 94.1, 99.5, and 99.6% for 3D CRT, VMAT, and HT, respectively, with the VMAT and HT plans having statistically significant increases in P+. If the optimal dose level is prescribed using a radiobiological evaluation method, as

  17. 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.)

  18. Helical tomo-therapy in the anal canal cancer: dosimetric comparison with conformal radiotherapy with intensity modulation and classical conformal radiotherapy

    International Nuclear Information System (INIS)

    Ozsahin, M.; Ugurluer, G.; Ballerini, G.; Letenneur, G.; Zouhair, A.; Mirimanoff, R.O.

    2009-01-01

    A dosimetry comparison was made between helical tomo-therapy, I.M.R.T. and classical conformal three dimensional radiotherapy for twelve first patients that received a image guided radiotherapy, the toxicity was tackled with a minimum follow-up of fourteen months. In conclusion, the CT-guided radiotherapy allows to save organs at risks superior to I.M.R.T. and conformal radiotherapy and a best homogeneity in the target volume. the toxicity is moderated and the break time is limited. (N.C.)

  19. TU-H-BRC-07: Therapeutic Benefit in Spatially Fractionated Radiotherapy (GRID) Using Helical Tomotherapy

    International Nuclear Information System (INIS)

    Narayanasamy, G; Zhang, X; Paudel, N; Morrill, S; Maraboyina, S; Peacock, L; Penagaricano, J; Meigooni, A; Liang, X

    2016-01-01

    Purpose: The aim of this project is to study the therapeutic ratio (TR) for helical Tomotherapy (HT) based spatially fractionated radiotherapy (GRID). Estimation of TR was based on the linear-quadratic cell survival model by comparing the normal cell survival in a HT GRID to that of a uniform dose delivery in an open-field for the same tumor survival. Methods: HT GRID plan was generated using a patient specific virtual GRID block pattern of non-divergent, cylinder shaped holes using MLCs. TR was defined as the ratio of normal tissue surviving fraction (SF) under HT GRID irradiation to an open field irradiation with an equivalent dose that result in the same tumor cell SF. The ratio was estimated from DVH data on ten patient plans with deep seated, bulky tumor approved by the treating radiation oncologist. Dependence of the TR values on radio-sensitivity of the tumor cells and prescription dose were also analyzed. Results: The mean ± standard deviation (SD) of TR was 4.0±0.7 (range: 3.1 to 5.5) for the 10 patients with single fraction dose of 20 Gy and tumor cell SF of 0.5 at 2 Gy. In addition, mean±SD of TR = 1±0.1 and 18.0±5.1 were found for tumor with SF of 0.3 and 0.7, respectively. Reducing the prescription dose to 15 and 10 Gy lowered the TR to 2.0±0.2 and 1.2±0.04 for a tumor cell SF of 0.5 at 2 Gy. In this study, the SF of normal cells was assumed to be 0.5 at 2 Gy. Conclusion: HT GRID displayed a significant therapeutic advantage over uniform dose from an open field irradiation. TR increases with the radioresistance of the tumor cells and with prescription dose.

  20. A Prospective Evaluation of Helical Tomotherapy

    International Nuclear Information System (INIS)

    Bauman, Glenn; Yartsev, Slav; Rodrigues, George; Lewis, Craig; Venkatesan, Varagur M.; Yu, Edward; Hammond, Alex; Perera, Francisco; Ash, Robert; Dar, A. Rashid; Lock, Michael; Baily, Laura; Coad, Terry C; Trenka, Kris C.; Warr, Barbara; Kron, Tomas; Battista, Jerry; Van Dyk, Jake

    2007-01-01

    Purpose: To report results from two clinical trials evaluating helical tomotherapy (HT). Methods and Materials: Patients were enrolled in one of two prospective trials of HT (one for palliative and one for radical treatment). Both an HT plan and a companion three-dimensional conformal radiotherapy (3D-CRT) plan were generated. Pretreatment megavoltage computed tomography was used for daily image guidance. Results: From September 2004 to January 2006, a total of 61 sites in 60 patients were treated. In all but one case, a clinically acceptable tomotherapy plan for treatment was generated. Helical tomotherapy plans were subjectively equivalent or superior to 3D-CRT in 95% of plans. Helical tomotherapy was deemed equivalent or superior in two thirds of dose-volume point comparisons. In cases of inferiority, differences were either clinically insignificant and/or reflected deliberate tradeoffs to optimize the HT plan. Overall imaging and treatment time (median) was 27 min (range, 16-91 min). According to a patient questionnaire, 78% of patients were satisfied to very satisfied with the treatment process. Conclusions: Helical tomotherapy demonstrated clear advantages over conventional 3D-CRT in this diverse patient group. The prospective trials were helpful in deploying this technology in a busy clinical setting

  1. Hippocampal-Sparing Whole-Brain Radiotherapy: A 'How-To' Technique Using Helical Tomotherapy and Linear Accelerator-Based Intensity-Modulated Radiotherapy

    International Nuclear Information System (INIS)

    Gondi, Vinai; Tolakanahalli, Ranjini; Mehta, Minesh P.; Tewatia, Dinesh; Rowley, Howard; Kuo, John S.; Khuntia, Deepak; Tome, Wolfgang A.

    2010-01-01

    Purpose: Sparing the hippocampus during cranial irradiation poses important technical challenges with respect to contouring and treatment planning. Herein we report our preliminary experience with whole-brain radiotherapy using hippocampal sparing for patients with brain metastases. Methods and Materials: Five anonymous patients previously treated with whole-brain radiotherapy with hippocampal sparing were reviewed. The hippocampus was contoured, and hippocampal avoidance regions were created using a 5-mm volumetric expansion around the hippocampus. Helical tomotherapy and linear accelerator (LINAC)-based intensity-modulated radiotherapy (IMRT) treatment plans were generated for a prescription dose of 30 Gy in 10 fractions. Results: On average, the hippocampal avoidance volume was 3.3 cm 3 , occupying 2.1% of the whole-brain planned target volume. Helical tomotherapy spared the hippocampus, with a median dose of 5.5 Gy and maximum dose of 12.8 Gy. LINAC-based IMRT spared the hippocampus, with a median dose of 7.8 Gy and maximum dose of 15.3 Gy. On a per-fraction basis, mean dose to the hippocampus (normalized to 2-Gy fractions) was reduced by 87% to 0.49 Gy 2 using helical tomotherapy and by 81% to 0.73 Gy 2 using LINAC-based IMRT. Target coverage and homogeneity was acceptable with both IMRT modalities, with differences largely attributed to more rapid dose fall-off with helical tomotherapy. Conclusion: Modern IMRT techniques allow for sparing of the hippocampus with acceptable target coverage and homogeneity. Based on compelling preclinical evidence, a Phase II cooperative group trial has been developed to test the postulated neurocognitive benefit.

  2. Skin-sparing Helical Tomotherapy vs 3D-conformal Radiotherapy for Adjuvant Breast Radiotherapy: In Vivo Skin Dosimetry Study

    International Nuclear Information System (INIS)

    Capelle, Lisa; Warkentin, Heather; MacKenzie, Marc; Joseph, Kurian; Gabos, Zsolt; Pervez, Nadeem; Tankel, Keith; Chafe, Susan; Amanie, John; Ghosh, Sunita; Parliament, Matthew; Abdulkarim, Bassam

    2012-01-01

    Purpose: We investigated whether treatment-planning system (TPS)-calculated dose accurately reflects skin dose received for patients receiving adjuvant breast radiotherapy (RT) with standard three-dimensional conformal RT (3D-CRT) or skin-sparing helical tomotherapy (HT). Methods and Materials: Fifty patients enrolled in a randomized controlled trial investigating acute skin toxicity from adjuvant breast RT with 3D-CRT compared to skin-sparing HT, where a 5-mm strip of ipsilateral breast skin was spared. Thermoluminescent dosimetry or optically stimulated luminescence measurements were made in multiple locations and were compared to TPS-calculated doses. Skin dosimetric parameters and acute skin toxicity were recorded in these patients. Results: With HT there was a significant correlation between calculated and measured dose in the medial and lateral ipsilateral breast (r = 0.67, P V50 (1.4% vs 5.9%, respectively; P=.001) but higher skin V40 and skin V30 (71.7% vs 64.0%, P=.02; and 99.0% vs 93.8%, P=.001, respectively) than 3D-CRT plans. Conclusion: The 3D-CRT TPS more accurately reflected skin dose than the HT TPS, which tended to overestimate dose received by 14% in patients receiving adjuvant breast RT.

  3. Adaptive radiotherapy for soft tissue changes during helical tomotherapy for head and neck cancer

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    Duma, M.N.; Kampfer, S.; Winkler, C.; Geinitz, H. [Universitaetsklinikum rechts der Isar, Muenchen (Germany). Dept. of Radiation Oncology; Schuster, T. [Universitaetsklinikum rechts der Isar, Muenchen (Germany). Inst. of Medical Statistics and Epidemiology

    2012-03-15

    The goal of the present study was to assess the frequency and impact of replanning triggered solely by soft tissue changes observed on the daily setup mega-voltage CT (MVCT) in head and neck cancer (H and N) helical tomotherapy (HT). A total of 11 patients underwent adaptive radiotherapy (ART) using MVCT. Preconditions were a soft tissue change > 0.5 cm and a tight mask. The dose-volume histograms (DVHs) derived from the initial planning kVCT (inPlan), the recalculated DVHs of the fraction (fx) when replanning was decided (actSit) and the DVHs of the new plan (adaptPlan) were compared. Assessed were the following: maximum dose (D{sub max}), minimum dose (D{sub min}), and mean dose (D{sub mean}) to the planning target volume (PTV) normalized to the prescribed dose; the D{sub mean}/fx to the parotid glands (PG), oral cavity (OC), and larynx (Lx); and the D{sub max}/fx to the spinal cord (SC) in Gy/fx. No patient had palpable soft tissue changes. The median weight loss at the moment of replanning was 2.3 kg. The median PTV D{sub mean} was 100% for inPlan, 103% for actSit, and 100% for adaptPlan. The PTV was always covered by the prescribed dose. A statistically significant increase was noted for all organs at risk (OAR) in the actSit. The D{sub mean} to the Lx, the D{sub mean} to the OC and the D{sub max} to the SC were statistically better in the adaptPlan. No statistically significant improvement was achieved by ART for the PGs. No significant correlations between weight and volume loss or between the volume changes of the organs to each other were observed, except a strong positive correlation of the shrinkage of the PGs ({rho} = + 0.77, p = 0.005). Soft tissue shrinkage without clinical palpable changes will not affect the coverage of the PTV, but translates into a higher delivered dose to the PTV itself and the normal tissue outside the PTV. The gain by ART in individual patients - especially in patients who receive doses close to the tolerance doses of the OAR

  4. Safety and Efficacy of Intensity-Modulated Stereotactic Body Radiotherapy Using Helical Tomotherapy for Lung Cancer and Lung Metastasis

    Directory of Open Access Journals (Sweden)

    Aiko Nagai

    2014-01-01

    Full Text Available Stereotactic body radiotherapy (SBRT proved to be an effective treatment with acceptable toxicity for lung tumors. However, the use of helical intensity-modulated (IM SBRT is controversial. We investigated the outcome of lung tumor patients treated by IMSBRT using helical tomotherapy with a Japanese standard fractionation schedule of 48 Gy in 4 fractions (n=37 or modified protocols of 50–60 Gy in 5–8 fractions (n=35. Median patient’s age was 76 years and median follow-up period for living patients was 20 months (range, 6–46. The median PTV was 6.9 cc in the 4-fraction group and 14 cc in the 5- to 8-fraction group (P=0.001. Grade 2 radiation pneumonitis was seen in 2 of 37 patients in the 4-fraction group and in 2 of 35 patients in the 5- to 8-fraction group (log-rank P=0.92. Other major complications were not observed. The LC rates at 2 years were 87% in the 4-fraction group and 83% in the 5- to 8-fraction group. Helical IMSBRT for lung tumors is safe and effective. Patients with a high risk of developing severe complications may also be safely treated using 5–8 fractions. The results of the current study warrant further studies of helical IMSBRT.

  5. An automatic dose verification system for adaptive radiotherapy for helical tomotherapy

    International Nuclear Information System (INIS)

    Mo, Xiaohu; Chen, Mingli; Parnell, Donald; Olivera, Gustavo; Galmarini, Daniel; Lu, Weiguo

    2014-01-01

    Purpose: During a typical 5-7 week treatment of external beam radiotherapy, there are potential differences between planned patient's anatomy and positioning, such as patient weight loss, or treatment setup. The discrepancies between planned and delivered doses resulting from these differences could be significant, especially in IMRT where dose distributions tightly conforms to target volumes while avoiding organs-at-risk. We developed an automatic system to monitor delivered dose using daily imaging. Methods: For each treatment, a merged image is generated by registering the daily pre-treatment setup image and planning CT using treatment position information extracted from the Tomotherapy archive. The treatment dose is then computed on this merged image using our in-house convolution-superposition based dose calculator implemented on GPU. The deformation field between merged and planning CT is computed using the Morphon algorithm. The planning structures and treatment doses are subsequently warped for analysis and dose accumulation. All results are saved in DICOM format with private tags and organized in a database. Due to the overwhelming amount of information generated, a customizable tolerance system is used to flag potential treatment errors or significant anatomical changes. A web-based system and a DICOM-RT viewer were developed for reporting and reviewing the results. Results: More than 30 patients were analysed retrospectively. Our in-house dose calculator passed 97% gamma test evaluated with 2% dose difference and 2mm distance-to-agreement compared with Tomotherapy calculated dose, which is considered sufficient for adaptive radiotherapy purposes. Evaluation of the deformable registration through visual inspection showed acceptable and consistent results, except for cases with large or unrealistic deformation. Our automatic flagging system was able to catch significant patient setup errors or anatomical changes. Conclusions: We developed an automatic

  6. The helical tomotherapy thread effect

    International Nuclear Information System (INIS)

    Kissick, M.W.; Fenwick, J.; James, J.A.; Jeraj, R.; Kapatoes, J.M.; Keller, H.; Mackie, T.R.; Olivera, G.; Soisson, E.T.

    2005-01-01

    Inherent to helical tomotherapy is a dose variation pattern that manifests as a 'ripple' (peak-to-trough relative to the average). This ripple is the result of helical beam junctioning, completely unique to helical tomotherapy. Pitch is defined as in helical CT, the couch travel distance for a complete gantry rotation relative to the axial beam width at the axis of rotation. Without scattering or beam divergence, an analytical posing of the problem as a simple integral predicts minima near a pitch of 1/n where n is an integer. A convolution-superposition dose calculator (TomoTherapy, Inc.) included all the physics needed to explore the ripple magnitude versus pitch and beam width. The results of the dose calculator and some benchmark measurements demonstrate that the ripple has sharp minima near p=0.86(1/n). The 0.86 factor is empirical and caused by a beam junctioning of the off-axis dose profiles which differ from the axial profiles as well as a long scatter tail of the profiles at depth. For very strong intensity modulation, the 0.86 factor may vary. The authors propose choosing particular minima pitches or using a second delivery that starts 180 deg off-phase from the first to reduce these ripples: 'Double threading'. For current typical pitches and beam widths, however, this effect is small and not clinically important for most situations. Certain extremely large field or high pitch cases, however, may benefit from mitigation of this effect

  7. Critical structure sparing in stereotactic ablative radiotherapy for central lung lesions: helical tomotherapy vs. volumetric modulated arc therapy.

    Directory of Open Access Journals (Sweden)

    Alexander Chi

    Full Text Available BACKGROUND: Helical tomotherapy (HT and volumetric modulated arc therapy (VMAT are both advanced techniques of delivering intensity-modulated radiotherapy (IMRT. Here, we conduct a study to compare HT and partial-arc VMAT in their ability to spare organs at risk (OARs when stereotactic ablative radiotherapy (SABR is delivered to treat centrally located early stage non-small-cell lung cancer or lung metastases. METHODS: 12 patients with centrally located lung lesions were randomly chosen. HT, 2 & 8 arc (Smart Arc, Pinnacle v9.0 plans were generated to deliver 70 Gy in 10 fractions to the planning target volume (PTV. Target and OAR dose parameters were compared. Each technique's ability to meet dose constraints was further investigated. RESULTS: HT and VMAT plans generated essentially equivalent PTV coverage and dose conformality indices, while a trend for improved dose homogeneity by increasing from 2 to 8 arcs was observed with VMAT. Increasing the number of arcs with VMAT also led to some improvement in OAR sparing. After normalizing to OAR dose constraints, HT was found to be superior to 2 or 8-arc VMAT for optimal OAR sparing (meeting all the dose constraints (p = 0.0004. All dose constraints were met in HT plans. Increasing from 2 to 8 arcs could not help achieve optimal OAR sparing for 4 patients. 2/4 of them had 3 immediately adjacent structures. CONCLUSION: HT appears to be superior to VMAT in OAR sparing mainly in cases which require conformal dose avoidance of multiple immediately adjacent OARs. For such cases, increasing the number of arcs in VMAT cannot significantly improve OAR sparing.

  8. A treatment planning study comparing helical tomotherapy with intensity-modulated radiotherapy for the treatment of anal cancer

    International Nuclear Information System (INIS)

    Joseph, Kurian Jones; Syme, Alasdair; Small, Cormac; Warkentin, Heather; Quon, Harvey; Ghosh, Sunita; Field, Colin; Pervez, Nadeem; Tankel, Keith; Patel, Samir; Usmani, Nawaid; Severin, Diane; Nijjar, Tirath; Fallone, Gino; Pedersen, John

    2010-01-01

    Purpose: A planning study to compare helical tomotherapy (HT) and intensity-modulated radiotherapy (IMRT) for the treatment of anal canal cancer. Materials and methods: Sixteen (8 males and 8 females) patients with anal cancer previously treated radically were identified. HT and IMRT plans were generated and dosimetric comparisons of the plans were performed. The planning goals were to deliver 54 Gy to the tumor (PTV 54Gy ) and 48 Gy to the nodes at risk (PTV Node ) in 30 fractions. Results: PTVs: HT plans were more homogeneous for both men and women. Male patients: HT vs. IMRT: D max : 55.87 ± 0.58 vs. 59.17 ± 3.24 (p = 0.036); D min : 52.91 ± 0.36 vs. 44.09 ± 6.84 (p = 0.012); female patients: HT vs. IMRT: D max : 56.14 ± 0.71 vs. 59.47 ± 0.81 (p = 0.012); D min : 52.36 ± 0.87 vs. 50.97 ± 1.42 (p = 0.028). OARs: In general, HT plans delivered a lower dose to the peritoneal cavity, external genitalia and the bladder and IMRT plans resulted in greater sparing of the pelvic bones (iliac crest/femur) for both men and women. Iliac crest/femur: the difference was significant only for the mean V10 Gy of iliac crest in women (p ≤ 0.012). External genitalia: HT plans achieved better sparing in women compared to men (p ≤ 0.046). For men, the mean doses were 18.96 ± 3.17 and 15.72 ± 3.21 for the HT and IMRT plan, respectively (p ≤ 0.017). Skin: both techniques achieved comparable sparing of the non-target skin (p = NS). Conclusions: HT and IMRT techniques achieved comparable target dose coverage and organ sparing, whereas HT plans were more homogeneous for both men and women.

  9. Total scalp irradiation using helical tomotherapy

    International Nuclear Information System (INIS)

    Orton, Nigel; Jaradat, Hazim; Welsh, James; Tome, Wolfgang

    2005-01-01

    Homogeneous irradiation of the scalp poses technical and dosimetric challenges due to the extensive, superficial, curved treatment volume. Conventional treatments on a linear accelerator use multiple matched electron fields or a combination of electron and photon fields. Problems with these techniques include dose heterogeneity in the target due to varying source-to-skin distance (SSD) and angle of beam incidence, significant dose to the brain, and the potential for overdose or underdose at match lines between the fields. Linac-based intensity-modulated radiation therapy (IMRT) plans have similar problems. This work presents treatment plans for total scalp irradiation on a helical tomotherapy machine. Helical tomotherapy is well-suited for scalp irradiation because it has the ability to deliver beamlets that are tangential to the scalp at all points. Helical tomotherapy also avoids problems associated with field matching and use of more than one modality. Tomotherapy treatment plans were generated and are compared to plans for treatment of the same patient on a linac. The resulting tomotherapy plans show more homogeneous target dose and improved critical structure dose when compared to state-of-the-art linac techniques. Target equivalent uniform dose (EUD) for the best tomotherapy plan was slightly higher than for the linac plan, while the volume of brain tissue receiving over 30 Gy was reduced by two thirds. Furthermore, the tomotherapy plan can be more reliably delivered than linac treatments, because the patient is aligned prior to each treatment based on megavoltage computed tomography (MVCT)

  10. Radiobiologic comparison of helical tomotherapy, intensity modulated radiotherapy, and conformal radiotherapy in treating lung cancer accounting for secondary malignancy risks

    Energy Technology Data Exchange (ETDEWEB)

    Komisopoulos, Georgios [Department of Medical Physics, Medical School, University of Patras, Patras (Greece); Mavroidis, Panayiotis, E-mail: mavroidis@uthscsa.edu [Department of Radiation Oncology, University of Texas Health Sciences Center at San Antonio, San Antonio, TX (United States); Department of Medical Radiation Physics, Karolinska Institutet and Stockholm University, Stockholm (Sweden); Rodriguez, Salvador; Stathakis, Sotirios; Papanikolaou, Nikos [Department of Radiation Oncology, University of Texas Health Sciences Center at San Antonio, San Antonio, TX (United States); Nikiforidis, Georgios C.; Sakellaropoulos, Georgios C. [Department of Medical Physics, Medical School, University of Patras, Patras (Greece)

    2014-01-01

    The aim of the present study is to examine the importance of using measures to predict the risk of inducing secondary malignancies in association with the clinical effectiveness of treatment plans in terms of tumor control and normal tissue complication probabilities. This is achieved by using radiobiologic parameters and measures, which may provide a closer association between clinical outcome and treatment delivery. Overall, 4 patients having been treated for lung cancer were examined. For each of them, 3 treatment plans were developed based on the helical tomotherapy (HT), multileaf collimator-based intensity modulated radiation therapy (IMRT), and 3-dimensional conformal radiation therapy (CRT) modalities. The different plans were evaluated using the complication-free tumor control probability (p{sub +}), the overall probability of injury (p{sub I}), the overall probability of control/benefit (p{sub B}), and the biologically effective uniform dose (D{sup ¯¯}). These radiobiologic measures were used to develop dose-response curves (p-D{sup ¯¯} diagram), which can help to evaluate different treatment plans when used in conjunction with standard dosimetric criteria. The risks for secondary malignancies in the heart and the contralateral lung were calculated for the 3 radiation modalities based on the corresponding dose-volume histograms (DVHs) of each patient. Regarding the overall evaluation of the different radiation modalities based on the p{sub +} index, the average values of the HT, IMRT, and CRT are 67.3%, 61.2%, and 68.2%, respectively. The corresponding average values of p{sub B} are 75.6%, 70.5%, and 71.0%, respectively, whereas the average values of p{sub I} are 8.3%, 9.3%, and 2.8%, respectively. Among the organs at risk (OARs), lungs show the highest probabilities for complications, which are 7.1%, 8.0%, and 1.3% for the HT, IMRT, and CRT modalities, respectively. Similarly, the biologically effective prescription doses (D{sub B}{sup ¯¯}) for the

  11. Conformal avoidance helical tomotherapy for dogs with nasopharyngeal tumors

    International Nuclear Information System (INIS)

    Welsh, J.S.; Turek, M.; Mackie, T.R.; Miller, P.; Mehta, M.P.; Forrest, L.J.

    2003-01-01

    Helical tomotherapy provides a unique means of delivering intensity-modulated radiation therapy (IMRT) using a novel treatment unit, which merges features of a linear accelerator with a helical CT scanner. Thanks to the CT imaging capacity, targeted regions can be visualized prior to, during, or immediately after each treatment. Such image-guidance through megavoltage CT will allow the realization and refinement of the concept of adaptive radiotherapy - the reconstruction of the actually delivered daily dose (as opposed to planned dose) accompanied by prescription adjustments when appropriate. In addition to this unique feature, helical tomotherapy promises further improvements in the specific avoidance of critical normal structures, i.e. conformal avoidance, the counterpart of conformal therapy. The first definitive treatment protocol using helical tomotherapy is presently underway for dogs with nasopharyngeal tumors. In general, such tumors can be treated with conventional external beam radiation therapy but at the cost of severe ocular toxicity due to the anatomy of the canine head. These are readily measurable toxicities and are almost universal in incidence; therefore, the canine nasopharyngeal tumor presents an ideal model to assess the ability to conformally avoid critical structures. It is hoped that conformal avoidance helical tomotherapy will improve tumor control via dose-escalation while reducing ocular toxicity in these veterinary patients. A total of 10 fractions are scheduled for these patients; the first 3 dogs have all received at least 7 fractions delivered via helical tomotherapy. Although preliminary, the first 3 dogs treated have not shown any evidence of ocular toxicity in this ongoing study

  12. A delivery transfer function (DTF) analysis for helical tomotherapy

    International Nuclear Information System (INIS)

    Kissick, Michael W; Mackie, Thomas Rockwell; Jeraj, Robert

    2007-01-01

    The previous theoretical work of a delivery transfer function (DTF) in radiotherapy is expanded to include the unique intensity modulation method of helical tomotherapy. In addition to the collimation of each beamlet, and the Gaussian scatter convolution spreading of the dose that other radiotherapy units have, helical tomotherapy uses 51 small arcs of varying lengths to adjust the intensity. The blurring from these arcs is not taken into account during treatment planning. A theoretical DTF is constructed, and a calculation is performed which includes this unique source motion in relation to the other DTF components. Various typical delivery parameters are used to generate resolution maps for a constant intensity projection. Near the isocenter, the transverse (to a given beam direction) blurring is small but at larger radii (>6 cm), the source blurring dominates over leaf size. For most clinical situations, this inherent source motion blurring is expected to be negligible

  13. Image-guided intensity modulated radiotherapy with helical tomotherapy for postoperative treatment of high-risk oral cavity cancer

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    Chen Yu-Jen

    2011-01-01

    Full Text Available Abstract Background The aim of this study was to assess the treatment results and toxicity profiles of helical tomotherapy (HT for postoperative high-risk oral cavity cancer. Methods From December 6, 2006 through October 9, 2009, 19 postoperative high-risk oral cavity cancer patients were enrolled. All of the patients received HT with (84% or without (16% chemotherapy. Results The median follow-up time was 17 months. The 2-year overall survival, disease-free survival, locoregional control, and distant metastasis-free rates were 94%, 84%, 92%, and 94%, respectively. The package of overall treatment time > 13 wk, the interval between surgery and radiation ≤ 6 wk, and the overall treatment time of radiation ≤ 7 wk was 21%, 84%, and 79%, respectively. The percentage of grade 3 mucositis, dermatitis, and leucopenia was 42%, 5% and 5%, respectively. Conclusions HT achieved encouraging clinical outcomes for postoperative high-risk oral cavity cancer patients with high compliance. A long-term follow-up study is needed to confirm these preliminary findings.

  14. Image-guided intensity modulated radiotherapy with helical tomotherapy for postoperative treatment of high-risk oral cavity cancer

    International Nuclear Information System (INIS)

    Hsieh, Chen-Hsi; Hsieh, Yen-Ping; Lin, Shoei Long; Chen, Chun-Yi; Chen, Chien-An; Shueng, Pei-Wei; Kuo, Ying-Shiung; Liao, Li-Jen; Hu, Kawang-Yu; Lin, Shih-Chiang; Wu, Le-Jung; Lin, Yu-Chin; Chen, Yu-Jen; Wang, Li-Ying

    2011-01-01

    The aim of this study was to assess the treatment results and toxicity profiles of helical tomotherapy (HT) for postoperative high-risk oral cavity cancer. From December 6, 2006 through October 9, 2009, 19 postoperative high-risk oral cavity cancer patients were enrolled. All of the patients received HT with (84%) or without (16%) chemotherapy. The median follow-up time was 17 months. The 2-year overall survival, disease-free survival, locoregional control, and distant metastasis-free rates were 94%, 84%, 92%, and 94%, respectively. The package of overall treatment time > 13 wk, the interval between surgery and radiation ≤ 6 wk, and the overall treatment time of radiation ≤ 7 wk was 21%, 84%, and 79%, respectively. The percentage of grade 3 mucositis, dermatitis, and leucopenia was 42%, 5% and 5%, respectively. HT achieved encouraging clinical outcomes for postoperative high-risk oral cavity cancer patients with high compliance. A long-term follow-up study is needed to confirm these preliminary findings

  15. Tomotherapy – a different way of dose delivery in radiotherapy

    Science.gov (United States)

    Skórska, Małgorzata; Jodda, Agata; Ryczkowski, Adam; Kaźmierska, Joanna; Adamska, Krystyna; Karczewska-Dzionk, Aldona; Żmijewska-Tomczak, Małgorzata; Włodarczyk, Hanna

    2012-01-01

    Aim of the study Helical tomotherapy is one of the methods of radiotherapy. This method enables treatment implementation for a wide spectrum of clinical cases. The vast array of therapeutic uses of helical tomotherapy results directly from the method of dose delivery, which is significantly different from the classic method developed for conventional linear accelerators. The paper discusses the method of dose delivery by a tomotherapy machine. Moreover, an analysis and presentation of treatment plans was performed in order to show the therapeutic possibilities of the applied technology. Dose distributions were obtained for anaplastic medulloblastoma, multifocal metastases to brain, vulva cancer, tongue cancer, metastases to bones, and advanced skin cancer. Tomotherapy treatment plans were compared with conventional linear accelerator plans. Results Following the comparative analysis of tomotherapy and conventional linear accelerator plans, in each case we obtained the increase in dose distribution conformity manifested in greater homogeneity of doses in the radiation target area for anaplastic medulloblastoma, multifocal metastases to brain, vulva cancer, metastases to bones, and advanced skin cancer, and the reduction of doses in organs at risk (OAR) for anaplastic medulloblastoma, vulva cancer, tongue cancer, and advanced skin cancer. The time of treatment delivery in the case of a tomotherapy machine is comparable to the implementation of the plan prepared in intensity-modulated radiotherapy (IMRT) technique for a conventional linear accelerator. In the case of tomotherapy the application of a fractional dose was carried out in each case during one working period of the machine. For a conventional linear accelerator the total value of the fractional dose in the case of anaplastic medulloblastoma and metastases to bones was delivered using several treatment plans, for which a change of set-up was necessary during a fraction. Conclusion The obtained results

  16. A Dosimetric Comparison of Accelerated Partial Breast Irradiation Techniques: Multicatheter Interstitial Brachytherapy, Three-Dimensional Conformal Radiotherapy, and Supine Versus Prone Helical Tomotherapy

    International Nuclear Information System (INIS)

    Patel, Rakesh R.; Becker, Stewart J.; Das, Rupak K.; Mackie, Thomas R.

    2007-01-01

    Purpose: To compare dosimetrically four different techniques of accelerated partial breast irradiation (APBI) in the same patient. Methods and Materials: Thirteen post-lumpectomy interstitial brachytherapy (IB) patients underwent imaging with preimplant computed tomography (CT) in the prone and supine position. These CT scans were then used to generate three-dimensional conformal radiotherapy (3D-CRT) and prone and supine helical tomotherapy (PT and ST, respectively) APBI plans and compared with the treated IB plans. Dose-volume histogram analysis and the mean dose (NTD mean ) values were compared. Results: Planning target volume coverage was excellent for all methods. Statistical significance was considered to be a p value mean dose of 1.3 Gy 3 and 1.2 Gy 3 , respectively. Both of these methods were statistically significantly lower than the supine external beam techniques. Overall, all four methods yielded similar low doses to the heart. Conclusions: The use of IB and PT resulted in greater normal tissue sparing (especially ipsilateral breast and lung) than the use of supine external beam techniques of 3D-CRT or ST. However, the choice of APBI technique must be tailored to the patient's anatomy, lumpectomy cavity location, and overall treatment goals

  17. Risk of radiation-induced pneumonitis after helical and static-port tomotherapy in lung cancer patients and experimental rats

    International Nuclear Information System (INIS)

    Zhang, Xianglan; Shin, You Keun; Zheng, Zhenlong; Zhu, Lianhua; Lee, Ik Jae

    2015-01-01

    Radiotherapy (RT) is one of the major non-operative treatment modalities for treating lung cancer. Tomotherapy is an advanced type of intensity-modulated radiotherapy (IMRT) in which radiation may be delivered in a helical fashion. However, unexpected pneumonitis may occur in patients treated with tomotherapy, especially in combination with chemotherapy, as a result of extensive low-dose radiation of large lung volumes. The aim of our study was to investigate the risk of radiation-induced pneumonitis after helical-mode and static-mode tomotherapy in patients with lung cancer and in an animal model. A total of 63 patients with primary lung cancer who were treated with static or helical tomotherapy with or without concurrent chemoradiotherapy (CCRT) were analyzed. Additionally, rats with radiation-induced pulmonary toxicity, which was induced by the application of helical or static tomography with or without CCRT, were evaluated. Helical-mode tomotherapy resulted in a significantly higher rate of late radiation pneumonitis in lung cancer patients than static-mode tomotherapy when evaluated by the Radiation Therapy Oncology Group (RTOG) and National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE) scoring system. In the animal model, helical tomotherapy alone induced significantly higher expression of interleukin (IL)-1α, IL-1β, IL-6, and transforming growth factor (TGF)-β in lung specimens, especially on the untreated side, compared to static tomotherapy alone. Additionally, rats treated with helical tomotherapy and CCRT demonstrated significantly higher expression of inflammatory cytokines compared to those treated with static tomotherapy and CCRT. Rat models treated with tomotherapy with or without CCRT could present similar patterns of pulmonary toxicity to those shown in lung cancer patients. The models can be used in further investigations of radiation induced pulmonary toxicity

  18. Helical tomotherapy. Experiences of the first 150 patients in Heidelberg

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    Sterzing, F.; Schubert, K.; Sroka-Perez, G.; Kalz, J.; Debus, J.; Herfarth, K. [Dept. of Radiation Oncology, Univ. of Heidelberg (Germany)

    2008-01-15

    Background and purpose: helical tomotherapy was introduced into clinical routine at the Department of Radiation Oncology, University Hospital of Heidelberg, Germany, in July 2006. This report is intended to describe the experience with the first 150 patients treated with helical tomotherapy. Patient selection, time effort, handling of daily image guidance with megavoltage (MV) CT, and quality of radiation plans shall be assessed. Patients and methods: between July 2006 and May 2007, 150 patients were treated with helical tomotherapy in the University Hospital of Heidelberg. Mean age was 60 years with a minimum of 30 years and a maximum of 85 years. 79 of these patients received radiotherapy as a part of multimodal treatment pre- or postoperatively, 17 patients received treatment as a combined radiochemotherapy. 76% were treated with curative intent. Radiotherapy sites were central nervous system (n = 7), head and neck (n = 28), thoracic (n = 37), abdominal (n = 58) and skeletal system (n = 20). Most common tumor entities were prostate cancer (n = 28), breast cancer (n = 17), gastrointestinal tumors (n = 19), pharyngeal carcinoma (n = 14), lymphoma (n = 13), metastatic disease (bone n = 14, liver n = 6, lung n = 4, lymph node n = 2), sarcoma (n = 8), malignant pleural mesothelioma (n = 5), ovarian cancer treated with whole abdominal irradiation (n = 4), lung cancer (n = 3), skin malignancies (n = 3), chordoma (n = 2), meningioma (n = 2), one ependymoma and one medulloblastoma treated with craniospinal axis irradiation (n = 2), and others (n = 4). Nine patients were treated with single-fraction radiosurgery, nine with image-guided spinal reirradiation, and twelve patients were treated at multiple targets simultaneously. A pretreatment MV-CT scan was performed in 98.2% of the 3,026 fractions applied. After matching with the kilovoltage planning CT, corrections for translations and rotation around longitudinal axis (roll) were done. Results: mean time on table was 24

  19. Quality assurance of a helical tomotherapy machine

    International Nuclear Information System (INIS)

    Fenwick, J D; Tome, W A; Jaradat, H A; Hui, S K; James, J A; Balog, J P; DeSouza, C N; Lucas, D B; Olivera, G H; Mackie, T R; Paliwal, B R

    2004-01-01

    Helical tomotherapy has been developed at the University of Wisconsin, and 'Hi-Art II' clinical machines are now commercially manufactured. At the core of each machine lies a ring-gantry-mounted short linear accelerator which generates x-rays that are collimated into a fan beam of intensity-modulated radiation by a binary multileaf, the modulation being variable with gantry angle. Patients are treated lying on a couch which is translated continuously through the bore of the machine as the gantry rotates. Highly conformal dose-distributions can be delivered using this technique, which is the therapy equivalent of spiral computed tomography. The approach requires synchrony of gantry rotation, couch translation, accelerator pulsing and the opening and closing of the leaves of the binary multileaf collimator used to modulate the radiation beam. In the course of clinically implementing helical tomotherapy, we have developed a quality assurance (QA) system for our machine. The system is analogous to that recommended for conventional clinical linear accelerator QA by AAPM Task Group 40 but contains some novel components, reflecting differences between the Hi-Art devices and conventional clinical accelerators. Here the design and dosimetric characteristics of Hi-Art machines are summarized and the QA system is set out along with experimental details of its implementation. Connections between this machine-based QA work, pre-treatment patient-specific delivery QA and fraction-by-fraction dose verification are discussed

  20. Can We Spare the Pancreas and Other Abdominal Organs at Risk? A Comparison of Conformal Radiotherapy, Helical Tomotherapy and Proton Beam Therapy in Pediatric Irradiation.

    Science.gov (United States)

    Jouglar, Emmanuel; Wagner, Antoine; Delpon, Grégory; Campion, Loïc; Meingan, Philippe; Bernier, Valérie; Demoor-Goldschmidt, Charlotte; Mahé, Marc-André; Lacornerie, Thomas; Supiot, Stéphane

    2016-01-01

    Late abdominal irradiation toxicity during childhood included renal damage, hepatic toxicity and secondary diabetes mellitus. We compared the potential of conformal radiotherapy (CRT), helical tomotherapy (HT) and proton beam therapy (PBT) to spare the abdominal organs at risk (pancreas, kidneys and liver- OAR) in children undergoing abdominal irradiation. We selected children with abdominal tumors who received more than 10 Gy to the abdomen. Treatment plans were calculated in order to keep the dose to abdominal OAR as low as possible while maintaining the same planned target volume (PTV) coverage. Dosimetric values were compared using the Wilcoxon signed-rank test. The dose distribution of 20 clinical cases with a median age of 8 years (range 1-14) were calculated with different doses to the PTV: 5 medulloblastomas (36 Gy), 3 left-sided and 2 right-sided nephroblastomas (14.4 Gy to the tumor + 10.8 Gy boost to para-aortic lymphnodes), 1 left-sided and 4 right-sided or midline neuroblastomas (21 Gy) and 5 Hodgkin lymphomas (19.8 Gy to the para-aortic lymphnodes and spleen). HT significantly reduced the mean dose to the whole pancreas (WP), the pancreatic tail (PT) and to the ipsilateral kidney compared to CRT. PBT reduced the mean dose to the WP and PT compared to both CRT and HT especially in midline and right-sided tumors. PBT decreased the mean dose to the ispilateral kidney but also to the contralateral kidney and the liver compared to CRT. Low dose to normal tissue was similar or increased with HT whereas integral dose and the volume of normal tissue receiving at least 5 and 10 Gy were reduced with PBT compared to CRT and HT. In children undergoing abdominal irradiation therapy, proton beam therapy reduces the dose to abdominal OAR while sparing normal tissue by limiting low dose irradiation.

  1. Bowel sparing in pediatric cranio-spinal radiotherapy: a comparison of combined electron and photon and helical TomoTherapy techniques to a standard photon method

    International Nuclear Information System (INIS)

    Harron, Elizabeth; Lewis, Joanne

    2012-01-01

    The aim of this study was to compare the dose to organs at risk (OARs) from different craniospinal radiotherapy treatment approaches available at the Northern Centre for Cancer Care (NCCC), with a particular emphasis on sparing the bowel. Method: Treatment plans were produced for a pediatric medulloblastoma patient with inflammatory bowel disease using 3D conformal 6-MV photons (3DCP), combined 3D 6-MV photons and 18-MeV electrons (3DPE), and helical photon TomoTherapy (HT). The 3DPE plan was a modification of the standard 3DCP technique, using electrons to treat the spine inferior to the level of the diaphragm. The plans were compared in terms of the dose-volume data to OARs and the nontumor integral dose. Results: The 3DPE plan was found to give the lowest dose to the bowel and the lowest nontumor integral dose of the 3 techniques. However, the coverage of the spine planning target volume (PTV) was least homogeneous using this technique, with only 74.6% of the PTV covered by 95% of the prescribed dose. HT was able to achieve the best coverage of the PTVs (99.0% of the whole-brain PTV and 93.1% of the spine PTV received 95% of the prescribed dose), but delivered a significantly higher integral dose. HT was able to spare the heart, thyroid, and eyes better than the linac-based techniques, but other OARs received a higher dose. Conclusions: Use of electrons was the best method for reducing the dose to the bowel and the integral dose, at the expense of compromised spine PTV coverage. For some patients, HT may be a viable method of improving dose homogeneity and reducing selected OAR doses.

  2. Superiority of conventional intensity-modulated radiotherapy over helical tomotherapy in locally advanced non-small cell lung cancer. A comparative plan analysis

    Energy Technology Data Exchange (ETDEWEB)

    Song, C. [National Cancer Center, Research Institute and Hospital, Goyang (Korea, Republic of). Proton Therapy Center; Seoul National Univ. College of Medicine (Korea, Republic of). Dept. of Radiation Oncology; Pyo, H.; Kim, J. [Sungkyunkwan Univ. School of Medicine, Samsung Medical Center, Seoul (Korea, Republic of). Dept. of Radiation Oncology; Lim, Y.K.; Kim, D.W.; Cho, K.H. [National Cancer Center, Research Institute and Hospital, Goyang (Korea, Republic of). Proton Therapy Center; Kim, W.C. [Inha Univ. School of Medicine, Incheon (Korea, Republic of). Dept. of Radiation Oncology; Kim, H.J. [Seoul National Univ. College of Medicine (Korea, Republic of). Dept. of Radiation Oncology

    2012-10-15

    Purpose: To compare helical tomotherapy (HT) and conventional intensity-modulated radiotherapy (IMRT) using a variety of dosimetric and radiobiologic indexes in patients with locally advanced non-small cell lung cancer (LA-NSCLC). Patients and methods: A total of 20 patients with LA-NSCLC were enrolled. IMRT plans with 4-6 coplanar beams and HT plans were generated for each patient. Dose distributions and dosimetric indexes for the tumors and critical structures were computed for both plans and compared. Results: Both modalities created highly conformal plans. They did not differ in the volumes of lung exposed to > 20 Gy of radiation. The average mean lung dose, volume receiving {>=} 30 Gy, and volume receiving {>=} 10 Gy in HT planning were 18.3 Gy, 18.5%, and 57.1%, respectively, compared to 19.4 Gy, 25.4%, and 48.9%, respectively, with IMRT (p = 0.004, p < 0.001, and p < 0.001). The differences between HT and IMRT in lung volume receiving {>=} 10-20 Gy increased significantly as the planning target volume (PTV) increased. For 6 patients who had PTV greater than 700 cm{sup 3}, IMRT was superior to HT for 5 patients in terms of lung volume receiving {>=} 5-20 Gy. The integral dose to the entire thorax in HT plans was significantly higher than in IMRT plans. Conclusion: HT gave significantly better control of mean lung dose and volume receiving {>=} 30-40 Gy, whereas IMRT provided better control of the lung volume receiving {>=} 5-15 Gy and the integral dose to entire thorax. In most patients with PTV greater than 700 cm{sup 3}, IMRT was superior to HT in terms of lung volume receiving {>=} 5-20 Gy. It is therefore advised that caution should be exercised when planning LA-NSCLC using HT. (orig.)

  3. Intensity-Modulated Radiotherapy (IMRT) vs Helical Tomotherapy (HT) in Concurrent Chemoradiotherapy (CRT) for Patients with Anal Canal Carcinoma (ACC): an analysis of dose distribution and toxicities

    International Nuclear Information System (INIS)

    Yeung, Rosanna; McConnell, Yarrow; Warkentin, Heather; Graham, Darren; Warkentin, Brad; Joseph, Kurian; Doll, Corinne M

    2015-01-01

    Intensity-modulated radiotherapy (IMRT) and helical tomotherapy (HT) have been adopted for radiotherapy treatment of anal canal carcinoma (ACC) due to better conformality, dose homogeneity and normal-tissue sparing compared to 3D-CRT. To date, only one published study compares dosimetric parameters of IMRT vs HT in ACC, but there are no published data comparing toxicities. Our objectives were to compare dosimetry and toxicities between these modalities. This is a retrospective study of 35 ACC patients treated with radical chemoradiotherapy at two tertiary cancer institutions from 2008–2010. The use of IMRT vs HT was primarily based on center availability. The majority of patients received fluorouracil (5-FU) and 1–2 cycles of mitomycin C (MMC); 2 received 5-FU and cisplatin. Primary tumor and elective nodes were prescribed to ≥54Gy and ≥45Gy, respectively. Patients were grouped into two cohorts: IMRT vs HT. The primary endpoint was a dosimetric comparison between the cohorts; the secondary endpoint was comparison of toxicities. 18 patients were treated with IMRT and 17 with HT. Most IMRT patients received 5-FU and 1 MMC cycle, while most HT patients received 2 MMC cycles (p < 0.01), based on center policy. HT achieved more homogenous coverage of the primary tumor (HT homogeneity and uniformity index 0.14 and 1.02 vs 0.29 and 1.06 for IMRT, p = 0.01 and p < 0.01). Elective nodal coverage did not differ. IMRT achieved better bladder, femoral head and peritoneal space sparing (V30 and V40, p ≤ 0.01), and lower mean skin dose (p < 0.01). HT delivered lower bone marrow (V10, p < 0.01) and external genitalia dose (V20 and V30, p < 0.01). Grade 2+ hematological and non-hematological toxicities were similar. Febrile neutropenia and unscheduled treatment breaks did not differ (both p = 0.13), nor did 3-year overall and disease-free survival (p = 0.13, p = 0.68). Chemoradiotherapy treatment of ACC using IMRT vs HT results in differences in dose homogenity and

  4. Rapid Arc, helical tomotherapy, sliding window intensity modulated radiotherapy and three dimensional conformal radiation for localized prostate cancer: A dosimetric comparison

    Directory of Open Access Journals (Sweden)

    Rajesh A Kinhikar

    2014-01-01

    Full Text Available Objective: The objective of this study was to investigate the potential role of RapidArc (RA compared with helical tomotherapy (HT, sliding window intensity modulated radiotherapy (SW IMRT and three-dimensional conformal radiation therapy (3D CRT for localized prostate cancer. Materials and Methods: Prescription doses ranged from 60 Gy to planning target volume (PTV and 66.25 Gy for clinical target volume prostate (CTV-P over 25-30 fractions. PTV and CTV-P coverage were evaluated by conformity index (CI and homogeneity index (HI. Organ sparing comparison was done with mean doses to rectum and bladder. Results: CI 95 were 1.0 ± 0.01 (RA, 0.99 ± 0.01 (HT, 0.97 ± 0.02 (IMRT, 0.98 ± 0.02 (3D CRT for PTV and 1.0 ± 0.00 (RA, HT, SW IMRT and 3D CRT for CTV-P. HI was 0.11 ± 0.03 (RA, 0.16 ± 0.08 (HT, 0.12 ± 0.03 (IMRT, 0.06 ± 0.01 (3D CRT for PTV and 0.03 ± 0.00 (RA, 0.05 ± 0.01 (HT, 0.03 ± 0.01 (SW IMRT and 3D CRT for CTV-P. Mean dose to bladder were 23.68 ± 13.23 Gy (RA, 24.55 ± 12.51 Gy (HT, 19.82 ± 11.61 Gy (IMRT and 23.56 ± 12.81 Gy (3D CRT, whereas mean dose to rectum was 36.85 ± 12.92 Gy (RA, 33.18 ± 11.12 Gy (HT, IMRT and 38.67 ± 12.84 Gy (3D CRT. Conclusion: All studied intensity-modulated techniques yield treatment plans of significantly improved quality when compared with 3D CRT, with HT providing best organs at risk sparing and RA being the most efficient treatment option, reducing treatment time to 1.45-3.7 min and monitor unit to <400 for a 2 Gy fraction.

  5. Dosimetric selection for helical tomotherapy based stereotactic ablative radiotherapy for early-stage non-small cell lung cancer or lung metastases.

    Directory of Open Access Journals (Sweden)

    Alexander Chi

    Full Text Available BACKGROUND: No selection criteria for helical tomotherapy (HT based stereotactic ablative radiotherapy (SABR to treat early stage non-small cell lung cancer (NSCLC or solitary lung metastases has been established. In this study, we investigate the dosimetric selection criteria for HT based SABR delivering 70 Gy in 10 fractions to avoid severe toxicity in the treatment of centrally located lesions when adequate target dose coverage is desired. MATERIALS AND METHODS: 78 HT-SABR plans for solitary lung lesions were created to prescribe 70 Gy in 10 fractions to the planning target volume (PTV. The PTV was set to have ≥95% PTV receiving 70 Gy in each case. The cases for which dose constraints for ≥1 OAR could not be met without compromising the target dose coverage were compared with cases for which all target and OAR dose constraints were met. RESULTS: There were 23 central lesions for which OAR dose constraints could not be met without compromising PTV dose coverage. Comparing to cases for which optimal HT-based SABR plans were generated, they were associated with larger tumor size (5.72±1.96 cm vs. 3.74±1.49 cm, p<0.0001, higher lung dose, increased number of immediately adjacent OARs ( 3.45±1.34 vs. 1.66±0.81, p<0.0001, and shorter distance to the closest OARs (GTV: 0.26±0.22 cm vs. 0.88±0.54 cm, p<0.0001; PTV 0.19±0.18 cm vs. 0.48±0.36 cm, p = 0.0001. CONCLUSION: Delivery of 70 Gy in 10 fractions with HT to meet all the given OAR and PTV dose constraints are most likely when the following parameters are met: lung lesions ≤3.78 cm (11.98 cc, ≤2 immediately adjacent OARs which are ≥0.45 cm from the gross lesion and ≥0.21 cm from the PTV.

  6. Toxic risk of stereotactic body radiotherapy and concurrent helical tomotherapy followed by erlotinib for non-small-cell lung cancer treatment - case report

    Directory of Open Access Journals (Sweden)

    Chen Chien-An

    2010-12-01

    Full Text Available Abstract Background Stereotactic body radiation therapy (SBRT applied by helical tomotherapy (HT is feasible for lung cancer in clinical. Using SBRT concurrently with erlotinib for non-small cell lung cancer (NSCLC is not reported previously. Case Presentation A 77-year-old man with stage III NSCLC, received erlotinib 150 mg/day, combined with image-guided SBRT via HT. A total tumor dose of 54 Gy/9 fractions was delivered to the tumor bed. The tumor responded dramatically and the combined regimen was well tolerated. After concurrent erlotinib-SBRT, erlotinib was continued as maintenance therapy. The patient developed dyspnea three months after the combined therapy and radiation pneumonitis with interstitial lung disease was suspected. Conclusions Combination SBRT, HT, and erlotinib therapy provided effective anti-tumor results. Nonetheless, the potential risks of enhanced adverse effects between radiation and erlotinib should be monitored closely, especially when SBRT is part of the regimen.

  7. Toxic risk of stereotactic body radiotherapy and concurrent helical tomotherapy followed by erlotinib for non-small-cell lung cancer treatment - case report

    International Nuclear Information System (INIS)

    Hsieh, Chen-Hsi; Chen, Chun-Yi; Shueng, Pei-Wei; Chang, Hou-Tai; Lin, Shih-Chiang; Chen, Yu-Jen; Wang, Li-Ying; Hsieh, Yen-Ping; Chen, Chien-An; Chong, Ngot-Swan; Lin, Shoei Long

    2010-01-01

    Stereotactic body radiation therapy (SBRT) applied by helical tomotherapy (HT) is feasible for lung cancer in clinical. Using SBRT concurrently with erlotinib for non-small cell lung cancer (NSCLC) is not reported previously. A 77-year-old man with stage III NSCLC, received erlotinib 150 mg/day, combined with image-guided SBRT via HT. A total tumor dose of 54 Gy/9 fractions was delivered to the tumor bed. The tumor responded dramatically and the combined regimen was well tolerated. After concurrent erlotinib-SBRT, erlotinib was continued as maintenance therapy. The patient developed dyspnea three months after the combined therapy and radiation pneumonitis with interstitial lung disease was suspected. Combination SBRT, HT, and erlotinib therapy provided effective anti-tumor results. Nonetheless, the potential risks of enhanced adverse effects between radiation and erlotinib should be monitored closely, especially when SBRT is part of the regimen

  8. Calibration of helical tomotherapy machine using EPR/alanine dosimetry.

    Science.gov (United States)

    Perichon, Nicolas; Garcia, Tristan; François, Pascal; Lourenço, Valérie; Lesven, Caroline; Bordy, Jean-Marc

    2011-03-01

    Current codes of practice for clinical reference dosimetry of high-energy photon beams in conventional radiotherapy recommend using a 10 x 10 cm2 square field, with the detector at a reference depth of 10 cm in water and 100 cm source to surface distance (SSD) (AAPM TG-51) or 100 cm source-to-axis distance (SAD) (IAEA TRS-398). However, the maximum field size of a helical tomotherapy (HT) machine is 40 x 5 cm2 defined at 85 cm SAD. These nonstandard conditions prevent a direct implementation of these protocols. The purpose of this study is twofold: To check the absorbed dose in water and dose rate calibration of a tomotherapy unit as well as the accuracy of the tomotherapy treatment planning system (TPS) calculations for a specific test case. Both topics are based on the use of electron paramagnetic resonance (EPR) using alanine as transfer dosimeter between the Laboratoire National Henri Becquerel (LNHB) 60Co-gamma-ray reference beam and the Institut Curie's HT beam. Irradiations performed in the LNHB reference 60Co-gamma-ray beam allowed setting up the calibration method, which was then implemented and tested at the LNHB 6 MV linac x-ray beam, resulting in a deviation of 1.6% (at a 1% standard uncertainty) relative to the reference value determined with the standard IAEA TRS-398 protocol. HT beam dose rate estimation shows a difference of 2% with the value stated by the manufacturer at a 2% standard uncertainty. A 4% deviation between measured dose and the calculation from the tomotherapy TPS was found. The latter was originated by an inadequate representation of the phantom CT-scan values and, consequently, mass densities within the phantom. This difference has been explained by the mass density values given by the CT-scan and used by the TPS which were not the true ones. Once corrected using Monte Carlo N-Particle simulations to validate the accuracy of this process, the difference between corrected TPS calculations and alanine measured dose values was then

  9. Head and neck region consolidation radiotherapy and prophylactic cranial irradiation with hippocampal avoidance delivered with helical tomotherapy after induction chemotherapy for non-sinonasal neuroendocrine carcinoma of the upper airways

    International Nuclear Information System (INIS)

    Franco, Pierfrancesco; La Porta, Maria Rosa; Girelli, Giuseppe; Borca, Valeria Casanova; Pasquino, Massimo; Tofani, Santi; Ozzello, Franca; Ricardi, Umberto; Numico, Gianmauro; Migliaccio, Fernanda; Catuzzo, Paola; Cante, Domenico; Ceroni, Paola; Sciacero, Piera; Carassai, Pierpaolo; Canzi, Paolo

    2012-01-01

    Non-sinonasal neuroendocrine carcinomas (NSNECs) of the head and neck are considered an unfrequent clinico-pathological entity. Combined modality treatment represents an established therapeutic option for undifferentiated forms where distant metastasis is a common pattern of failure. We report on a case of NSNEC treated with sequential chemo-radiation consisting of 6 cycles of cisplatin and etoposide followed by loco-regional radiation to the head and neck and simultaneous prophylactic cranial irradiation to prevent from intracranial spread, delivered with helical tomotherapy with the 'hippocampal avoidance' technique in order to reduce neuro-cognitive late effects. One year after the end of the whole combined modality approach, the patient achieved complete remission, with no treatment-related sub-acute and late effects. The present report highlights the importance of multidisciplinary management for NSNECs of the head and neck, as the possibility to achieve substantial cure rates with mild side effects with modern radiotherapy techniques

  10. An absolute dose determination of helical tomotherapy accelerator, TomoTherapy High-Art II

    International Nuclear Information System (INIS)

    Bailat, Claude J.; Buchillier, Thierry; Pachoud, Marc; Moeckli, Raphaeel; Bochud, Francois O.

    2009-01-01

    Purpose: A helical tomotherapy accelerator presents a dosimetric challenge because, to this day, there is no internationally accepted protocol for the determination of the absolute dose. Because of this reality, we investigated the different alternatives for characterizing and measuring the absolute dose of such an accelerator. We tested several dosimetric techniques with various metrological traceabilities as well as using a number of phantoms in static and helical modes. Methods: Firstly, the relationship between the reading of ionization chambers and the absorbed dose is dependent on the beam quality value of the photon beam. For high energy photons, the beam quality is specified by the tissue phantom ratio (TPR 20,10 ) and it is therefore necessary to know the TPR 20,10 to calculate the dose delivered by a given accelerator. This parameter is obtained through the ratio of the absorbed dose at 20 and 10 cm depths in water and was measured in the particular conditions of the tomotherapy accelerator. Afterward, measurements were performed using the ionization chamber (model A1SL) delivered as a reference instrument by the vendor. This chamber is traceable in absorbed dose to water in a Co-60 beam to a water calorimeter of the American metrology institute (NIST). Similarly, in Switzerland, each radiotherapy department is directly traceable to the Swiss metrology institute (METAS) in absorbed dose to water based on a water calorimeter. For our research, this traceability was obtained by using an ionization chamber traceable to METAS (model NE 2611A), which is the secondary standard of our institute. Furthermore, in order to have another fully independent measurement method, we determined the dose using alanine dosimeters provided by and traceable to the British metrology institute (NPL); they are calibrated in absorbed dose to water using a graphite calorimeter. And finally, we wanted to take into account the type of chamber routinely used in clinical practice and

  11. Helical Tomotherapy-Based STAT RT: Dosimetric Evaluation for Clinical Implementation of a Rapid Radiation Palliation Program

    International Nuclear Information System (INIS)

    McIntosh, Alyson; Dunlap, Neal; Sheng, Ke; Geezey, Constance; Turner, Benton; Blackhall, Leslie; Weiss, Geoffrey; Lappinen, Eric; Larner, James M.; Read, Paul W.

    2010-01-01

    Helical tomotherapy-based STAT radiation therapy (RT) uses an efficient software algorithm for rapid intensity-modulated treatment planning, enabling conformal radiation treatment plans to be generated on megavoltage computed tomography (MVCT) scans for CT simulation, treatment planning, and treatment delivery in one session. We compared helical tomotherapy-based STAT RT dosimetry with standard linac-based 3D conformal plans and standard helical tomotherapy-based intensity-modulated radiation therapy (IMRT) dosimetry for palliative treatments of whole brain, a central obstructive lung mass, multilevel spine disease, and a hip metastasis. Specifically, we compared the conformality, homogeneity, and dose with regional organs at risk (OARs) for each plan as an initial step in the clinical implementation of a STAT RT rapid radiation palliation program. Hypothetical planning target volumes (PTVs) were contoured on an anthropomorphic phantom in the lung, spine, brain, and hip. Treatment plans were created using three planning techniques: 3D conformal on Pinnacle 3 , helical tomotherapy, and helical tomotherapy-based STAT RT. Plan homogeneity, conformality, and dose to OARs were analyzed and compared. STAT RT and tomotherapy improved conformality indices for spine and lung plans (CI spine = 1.21, 1.17; CI lung = 1.20, 1.07, respectively) in comparison with standard palliative anteroposterior/posteroanterior (AP/PA) treatment plans (CI spine = 7.01, CI lung = 7.30), with better sparing of heart, esophagus, and spinal cord. For palliative whole-brain radiotherapy, STAT RT and tomotherapy reduced maximum and mean doses to the orbits and lens (maximum/mean lens dose: STAT RT = 2.94/2.65 Gy, tomotherapy = 3.13/2.80 Gy, Lateral opposed fields = 7.02/3.65 Gy), with an increased dose to the scalp (mean scalp dose: STAT RT = 16.19 Gy, tomotherapy = 15.61 Gy, lateral opposed fields = 14.01 Gy). For bony metastatic hip lesions, conformality with both tomotherapy techniques (CI = 1

  12. Asymmetric fan beams (AFB) for improvement of the craniocaudal dose distribution in helical tomotherapy delivery

    International Nuclear Information System (INIS)

    Gladwish, Adam; Kron, Tomas; McNiven, Andrea; Bauman, Glenn; Van Dyk, Jake

    2004-01-01

    Helical tomotherapy (HT) is a novel radiotherapy technique that utilizes intensity modulated fan beams that deliver highly conformal dose distributions in a helical beam trajectory. The most significant limitation in dose delivery with a constant fan beam thickness (FBT) is the penumbra width of the dose distribution in the craniocaudal direction, which is equivalent to the FBT. We propose to employ a half-blocked fan beam at start and stop location to reduce the penumbra width by half. By opening the jaw slowly during the helical delivery until the desired FBT is achieved it is possible to create a sharper edge in the superior and inferior direction from the target. The technique was studied using a tomotherapy beam model implemented on a commercial treatment planning system (Theraplan Plus V3.0). It was demonstrated that the dose distribution delivered using a 25 mm fan beam can be improved significantly, to reduce the dose to normal structures located superiorly and inferiorly of the target. Dosimetry for this technique is straightforward down to a FBT of 15 mm and implementation should be simple as no changes in couch movement are required compared to a standard HT delivery. We conclude that the use of asymmetric collimated fan beams for the start and stop of the helical tomotherapeutic dose delivery has the potential of significantly improving the dose distribution in helical tomotherapy

  13. Helical tomotherapy as a new treatment technique for whole abdominal irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Rochet, N.; Sterzing, F.; Jensen, A.; Herfarth, K.; Schubert, K.; Debus, J.; Harms, W. [Heidelberg Univ. (Germany). Dept. of Radiation Oncology; Dinkel, J. [German Cancer Research Center (dkfz), Heidelberg (Germany). Dept. of Radiology; Eichbaum, M.; Schneeweiss, A.; Sohn, C. [Heidelberg Univ. (Germany). Dept. of Gynecology and Obstetrics

    2008-03-15

    Purpose: To describe a new intensity-modulated radiotherapy (IMRT) technique using helical tomotherapy for whole abdominal irradiation (WAI) in patients with advanced ovarian cancer. Material and Methods: A patient with radically operated ovarian cancer FIGO stage IIIc was treated in a prospective clinical trial with WAI to a total dose of 30 Gy in 1.5-Gy fractions as an additional therapy after adjuvant platinum-based chemotherapy. The planning target volume (PTV) included the entire peritoneal cavity. PTV was adapted according to breathing motion as detected in a four-dimensional respiratory-triggered computed tomography (4D-CT). Inverse treatment planning was done with the Hi-Art tomotherapy planning station. Organs at risk (OARs) were kidneys, liver, bone marrow, spinal cord, thoracic and lumbosacral vertebral bodies, and pelvic bones. Daily control of positioning accuracy was performed with megavoltage computed tomography (MV-CT). Results: Helical tomotherapy enabled a very homogeneous dose distribution with excellent sparing of OARs and coverage of the PTV (V90 of 93.1%, V95 of 86.9%, V105 of 1.9%, and V110 of 0.01%). Mean liver dose was 21.57 Gy and mean kidney doses were 9.75 Gy and 9.14 Gy, respectively. Treatment could be performed in 18.1 min daily and no severe side effects occurred. Conclusion: Helical tomotherapy is feasible and fast for WAI. Tomotherapy enabled excellent coverage of the PTV and effective sparing of liver, kidneys and bone marrow. (orig.)

  14. Helical tomotherapy as a new treatment technique for whole abdominal irradiation

    International Nuclear Information System (INIS)

    Rochet, N.; Sterzing, F.; Jensen, A.; Herfarth, K.; Schubert, K.; Debus, J.; Harms, W.; Dinkel, J.; Eichbaum, M.; Schneeweiss, A.; Sohn, C.

    2008-01-01

    Purpose: To describe a new intensity-modulated radiotherapy (IMRT) technique using helical tomotherapy for whole abdominal irradiation (WAI) in patients with advanced ovarian cancer. Material and Methods: A patient with radically operated ovarian cancer FIGO stage IIIc was treated in a prospective clinical trial with WAI to a total dose of 30 Gy in 1.5-Gy fractions as an additional therapy after adjuvant platinum-based chemotherapy. The planning target volume (PTV) included the entire peritoneal cavity. PTV was adapted according to breathing motion as detected in a four-dimensional respiratory-triggered computed tomography (4D-CT). Inverse treatment planning was done with the Hi-Art tomotherapy planning station. Organs at risk (OARs) were kidneys, liver, bone marrow, spinal cord, thoracic and lumbosacral vertebral bodies, and pelvic bones. Daily control of positioning accuracy was performed with megavoltage computed tomography (MV-CT). Results: Helical tomotherapy enabled a very homogeneous dose distribution with excellent sparing of OARs and coverage of the PTV (V90 of 93.1%, V95 of 86.9%, V105 of 1.9%, and V110 of 0.01%). Mean liver dose was 21.57 Gy and mean kidney doses were 9.75 Gy and 9.14 Gy, respectively. Treatment could be performed in 18.1 min daily and no severe side effects occurred. Conclusion: Helical tomotherapy is feasible and fast for WAI. Tomotherapy enabled excellent coverage of the PTV and effective sparing of liver, kidneys and bone marrow. (orig.)

  15. Dosimetric verification of helical tomotherapy for total scalp irradiation

    International Nuclear Information System (INIS)

    Hardcastle, Nicholas; Soisson, Emilie; Metcalfe, Peter; Rosenfeld, Anatoly B.; Tome, Wolfgang A.

    2008-01-01

    Total scalp irradiation is a treatment technique used for a variety of superficial malignancies. Helical tomotherapy is an effective technique used for total scalp irradiation. Recent published work has shown the TomoTherapy planning system to overestimate the superficial dose. In this study, the superficial doses for a helical tomotherapy total scalp irradiation have been measured on an anthropomorphic phantom using radiochromic and radiographic film as well as a new skin dosimeter, the MOSkin. The superficial dose was found to be accurately calculated by the TomoTherapy planning system. This is in contrast to recent reports, probably due to a combination of the smaller dose grid resolution used in planning and this particular treatment primarily consisting of beamlets tangential to the scalp. The superficial dose was found to increase from 33.6 to 41.2 Gy and 36.0 to 42.0 Gy over the first 2 mm depth in the phantom in selected regions of the PTV, measured with radiochromic film. The prescription dose was 40 Gy. The superficial dose was at the prescription dose or higher in some regions due to the bolus effect of the thermoplastic head mask and the head rest used to aid treatment setup. It is suggested that to achieve the prescription dose at the surface (≤2 mm depth) bolus or a custom thermoplastic helmet is used.

  16. Gating-by-rotation: a solution to the problem of intratreatment motion in helical tomotherapy

    International Nuclear Information System (INIS)

    Kapatoes, J.M.; Olivera, G.H.; Schloesser, E.A.; Pearson, D.W.; Balog, J.P.; Ruchala, K.J.; Schmidt, R.; Reckwerdt, P.J.; Mehta, M.P.; Mackie, T.R.

    2001-01-01

    Purpose: To assess the feasibility of addressing intratreatment motion issues in helical tomotherapy by gating the treatments by rotation. Intratreatment motion is a problem common to all IMRT techniques. Traditional methods of gating in conformal radiotherapy and some forms of IMRT are not applicable to helical tomotherapy due to the continuous rotation of the gantry. An alternative method is presented. Materials and Methods: Rotation-gating in helical tomotherapy is the process in which one rotation of treatment is immediately followed by a rotation of non-treatment. This on-off strategy is repeated for the full treatment volume. During the treatment rotations, the patient is required to hold their breath while the intensity-modulated fan beam deposits dose. For the non-treatment rotations, the patient is allowed to breathe freely as all leaves of the MLC will be closed, the accelerator disabled, or both. The couch indexes normally for treatment rotations and holds the patient stationary during non-treatment rotations. An investigation was conducted to assess the feasibility of rotation-gating. Film was placed between two hemispheres of a water phantom and a continuous helical delivery was carried out with all leaves opened. The film was replaced and another treatment was performed employing rotation-gating. The two films were compared to assess the process. The films were irradiated to dose levels within the linear region of the film response curve (maximum film dose ∼35 cGy). Films were also acquired with all leaves closed to quantify leakage dose through the collimation systems. Results: Central profiles for the inferior-superior direction (parallel to the direction of translation) for both films are displayed in Figure 1. The profiles agree very well, illustrating that a rotation-gated treatment closely mimics a continuous helical delivery. The only significant discrepancy lay in the tails of the profiles: a higher film dose is seen for the rotation

  17. Simultaneous Multitarget Irradiation Using Helical Tomotherapy for Advanced Hepatocellular Carcinoma With Multiple Extrahepatic Metastases

    International Nuclear Information System (INIS)

    Jang, Jeong Won; Kay, Chul Seung; You, Chan Ran; Kim, Chang Wook; Bae, Si Hyun.; Choi, Jong Young; Yoon, Seung Kew; Han, Chi Wha; Jung, Hyun Suk; Choi, Ihl Bong

    2009-01-01

    Purpose: The prognosis of hepatocellular carcinoma (HCC) patients with extrahepatic metastases is extremely poor. Helical tomotherapy, an image-guided, intensity-modulated radiotherapy system, can allow for simultaneous and precise targeting of multiple cancerous lesions, while sparing normal tissues. This study evaluated the feasibility and outcome of tomotherapy for advanced HCC with metastases. Patients and Methods: A total of 42 consecutive HCC patients with metastases were treated with tomotherapy using the Hi-Art system. A total of 152 intra- and extrahepatic lesions (3.5 lesions/patient) were treated simultaneously, with a dose of 51.03 Gy (range, 30-57.61) in 10 fractions. Transarterial chemolipiodolization using epirubicin (50 mg) and cisplatin (60 mg) was repeated in patients with intrahepatic HCC (mean size, 9.0 cm) after tomotherapy. Results: An objective response (complete response and partial response) was achieved in 45.2% of patients with intrahepatic tumors, 68.4% of patients with pulmonary lesions, 60.0% of patients with lymph node/adrenal lesions, and 66.7% of patients with soft-tissue metastases. The complete response rate for those with pulmonary and lymph node/adrenal metastases was 26.3% and 5.0%, respectively. The overall survival rate at 1 and 2 years was 50.1% and 14.9%, respectively, with a median survival of 12.3 months. The actuarial in-field tumor control rate for ≤1 year was 79.0%. No cases of Grade 4-5 acute toxicity occurred. Conclusion: The results of this study have shown that helical tomotherapy is safe and feasible without major toxicities for the treatment of advanced HCC and results in excellent tumor control and a potential survival benefit. This approach is expected to be a useful palliative option for selected HCC patients with metastases.

  18. Performance characteristics of an independent dose verification program for helical tomotherapy

    Directory of Open Access Journals (Sweden)

    Isaac C. F. Chang

    2017-01-01

    Full Text Available Helical tomotherapy with its advanced method of intensity-modulated radiation therapy delivery has been used clinically for over 20 years. The standard delivery quality assurance procedure to measure the accuracy of delivered radiation dose from each treatment plan to a phantom is time-consuming. RadCalc®, a radiotherapy dose verification software, has released specifically for beta testing a module for tomotherapy plan dose calculations. RadCalc®'s accuracy for tomotherapy dose calculations was evaluated through examination of point doses in ten lung and ten prostate clinical plans. Doses calculated by the TomoHDA™ tomotherapy treatment planning system were used as the baseline. For lung cases, RadCalc® overestimated point doses in the lung by an average of 13%. Doses within the spinal cord and esophagus were overestimated by 10%. Prostate plans showed better agreement, with overestimations of 6% in the prostate, bladder, and rectum. The systematic overestimation likely resulted from limitations of the pencil beam dose calculation algorithm implemented by RadCalc®. Limitations were more severe in areas of greater inhomogeneity and less prominent in regions of homogeneity with densities closer to 1 g/cm3. Recommendations for RadCalc® dose calculation algorithms and anatomical representation were provided based on the results of the study.

  19. Development of a software tool for the management of quality control in a helical tomotherapy unit

    International Nuclear Information System (INIS)

    Garcia Repiso, S.; Hernandez Rodriguez, J.; Martin Rincon, C.; Ramos Pacho, J. A.; Verde Velasco, J. M.; Delgado Aparacio, J. M.; Perez Alvarez, M. e.; Gomez Gonzalez, N.; Cons Perez, V.; Saez Beltran, M.

    2013-01-01

    The large amount of data and information that is managed in units of external radiotherapy quality control tests makes necessary the use of tools that facilitate, on the one hand, the management of measures and results in real time, and on other tasks of management, file, query and reporting of stored data. This paper presents an application of software of own development which is used for the integral management of the helical TomoTherapy unit in the aspects related to the roles and responsibilities of the hospital Radiophysics. (Author)

  20. Motion-induced dose artifacts in helical tomotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Bryan; Chen, Jeff; Battista, Jerry [London Regional Cancer Program, London Health Sciences Centre, London, ON (Canada); Kron, Tomas [Peter MacCallum Cancer Center, Melbourne (Australia)], E-mail: bryan.kim@lhsc.on.ca

    2009-10-07

    Tumor motion is a particular concern for a complex treatment modality such as helical tomotherapy, where couch position, gantry rotation and MLC leaf opening all change with time. In the present study, we have investigated the impact of tumor motion for helical tomotherapy, which could result in three distinct motion-induced dose artifacts, namely (1) dose rounding, (2) dose rippling and (3) IMRT leaf opening asynchronization effect. Dose rounding and dose rippling effects have been previously described, while the IMRT leaf opening asynchronization effect is a newly discovered motion-induced dose artifact. Dose rounding is the penumbral widening of a delivered dose distribution near the edges of a target volume along the direction of tumor motion. Dose rippling is a series of periodic dose peaks and valleys observed within the target region along the direction of couch motion, due to an asynchronous interplay between the couch motion and the longitudinal component of tumor motion. The IMRT leaf opening asynchronization effect is caused by an asynchronous interplay between the temporal patterns of leaf openings and tumor motion. The characteristics of each dose artifact were investigated individually as functions of target motion amplitude and period for both non-IMRT and IMRT helical tomotherapy cases, through computer simulation modeling and experimental verification. The longitudinal dose profiles generated by the simulation program agreed with the experimental data within {+-}0.5% and {+-}1.5% inside the PTV region for the non-IMRT and IMRT cases, respectively. The dose rounding effect produced a penumbral increase up to 20.5 mm for peak-to-peak target motion amplitudes ranging from 1.0 cm to 5.0 cm. Maximum dose rippling magnitude of 25% was calculated, when the target motion period approached an unusually high value of 10 s. The IMRT leaf opening asynchronization effect produced dose differences ranging from -29% to 7% inside the PTV region. This information

  1. A novel method to correct for pitch and yaw patient setup errors in helical tomotherapy

    International Nuclear Information System (INIS)

    Boswell, Sarah A.; Jeraj, Robert; Ruchala, Kenneth J.; Olivera, Gustavo H.; Jaradat, Hazim A.; James, Joshua A.; Gutierrez, Alonso; Pearson, Dave; Frank, Gary; Mackie, T. Rock

    2005-01-01

    An accurate means of determining and correcting for daily patient setup errors is important to the cancer outcome in radiotherapy. While many tools have been developed to detect setup errors, difficulty may arise in accurately adjusting the patient to account for the rotational error components. A novel, automated method to correct for rotational patient setup errors in helical tomotherapy is proposed for a treatment couch that is restricted to motion along translational axes. In tomotherapy, only a narrow superior/inferior section of the target receives a dose at any instant, thus rotations in the sagittal and coronal planes may be approximately corrected for by very slow continuous couch motion in a direction perpendicular to the scanning direction. Results from proof-of-principle tests indicate that the method improves the accuracy of treatment delivery, especially for long and narrow targets. Rotational corrections about an axis perpendicular to the transverse plane continue to be implemented easily in tomotherapy by adjustment of the initial gantry angle

  2. Independent quality assurance of a helical tomotherapy machine using the dose magnifying glass

    International Nuclear Information System (INIS)

    Wong, J. H. D.; Hardcastle, N.; Tome, W. A.

    2011-01-01

    Purpose: Helical tomotherapy is a complex delivery technique, integrating CT image guidance and intensity modulated radiotherapy in a single system. The integration of the CT detector ring on the gantry not only allows patient position verification but is also often used to perform various QA procedures. This convenience lacks the rigor of a machine-independent QA process. Methods: In this article, a Si strip detector, known as the Dose Magnifying Glass (DMG), was used to perform machine-independent QA measurements of the multileaf collimator alignment, leaf open time threshold, and leaf fluence output factor (LFOF). Results: The DMG measurements showed good agreements with EDR2 film for the MLC alignment test while the CT detector agrees well with DMG measurements for leaf open time threshold and LFOF measurements. The leaf open time threshold was found to be approximately 20 ms. The LFOF measured with the DMG agreed within error with the CT detector measured LFOF. Conclusions: The DMG with its 0.2 mm spatial resolution coupled to TERA ASIC allowed real-time high temporal resolution measurements of the tomotherapy leaf movement. In conclusion, DMG was shown to be a suitable tool for machine-independent QA of a tomotherapy unit.

  3. Independent quality assurance of a helical tomotherapy machine using the dose magnifying glass.

    Science.gov (United States)

    Wong, J H D; Hardcastle, N; Tomé, W A; Bayliss, A; Tolakanahalli, R; Lerch, M L F; Petasecca, M; Carolan, M; Metcalfe, P; Rosenfeld, A B

    2011-04-01

    Helical tomotherapy is a complex delivery technique, integrating CT image guidance and intensity modulated radiotherapy in a single system. The integration of the CT detector ring on the gantry not only allows patient position verification but is also often used to perform various QA procedures. This convenience lacks the rigor of a machine-independent QA process. In this article, a Si strip detector, known as the Dose Magnifying Glass (DMG), was used to perform machine-independent QA measurements of the multileaf collimator alignment, leaf open time threshold, and leaf fluence output factor (LFOF). The DMG measurements showed good agreements with EDR2 film for the MLC alignment test while the CT detector agrees well with DMG measurements for leaf open time threshold and LFOF measurements. The leaf open time threshold was found to be approximately 20 ms. The LFOF measured with the DMG agreed within error with the CT detector measured LFOF. The DMG with its 0.2 mm spatial resolution coupled to TERA ASIC allowed real-time high temporal resolution measurements of the tomotherapy leaf movement. In conclusion, DMG was shown to be a suitable tool for machine-independent QA of a tomotherapy unit.

  4. Phase II Study of Preoperative Helical Tomotherapy With a Simultaneous Integrated Boost for Rectal Cancer

    International Nuclear Information System (INIS)

    Engels, Benedikt; Tournel, Koen; Everaert, Hendrik; Hoorens, Anne; Sermeus, Alexandra; Christian, Nicolas; Storme, Guy; Verellen, Dirk; De Ridder, Mark

    2012-01-01

    Purpose: The addition of concomitant chemotherapy to preoperative radiotherapy is considered the standard of care for patients with cT3–4 rectal cancer. The combined treatment modality increases the complete response rate and local control (LC), but has no impact on survival or the incidence of distant metastases. In addition, it is associated with considerable toxicity. As an alternative strategy, we explored prospectively, preoperative helical tomotherapy with a simultaneous integrated boost (SIB). Methods and Materials: A total of 108 patients were treated with intensity-modulated and image-guided radiotherapy using the Tomotherapy Hi-Art II system. A dose of 46 Gy, in daily fractions of 2 Gy, was delivered to the mesorectum and draining lymph nodes, without concomitant chemotherapy. Patients with an anticipated circumferential resection margin (CRM) of less than 2 mm, based on magnetic resonance imaging, received a SIB to the tumor up to a total dose of 55.2 Gy. Acute and late side effects were scored using the National Cancer Institute Common Terminology Criteria for Adverse Events version 3.0. Results: A total of 102 patients presented with cT3–4 tumors; 57 patients entered the boost group and 51 the no-boost group. One patient in the no-boost group developed a radio-hypersensitivity reaction, resulting in a complete tumor remission, a Grade 3 acute and Grade 5 late enteritis. No other Grade ≥3 acute toxicities occurred. With a median follow-up of 32 months, Grade ≥3 late gastrointestinal and urinary toxicity were observed in 6% and 4% of the patients, respectively. The actuarial 2-year LC, progression-free survival and overall survival were 98%, 79%, and 93%. Conclusions: Preoperative helical tomotherapy displays a favorable acute toxicity profile in patients with cT3–4 rectal cancer. A SIB can be safely administered in patients with a narrow CRM and resulted in a promising LC.

  5. Image-guided total marrow and total lymphatic irradiation using helical tomotherapy

    International Nuclear Information System (INIS)

    Schultheiss, Timothy E.; Wong, Jeffrey; Liu, An; Olivera, Gustavo; Somlo, George

    2007-01-01

    Purpose: To develop a treatment technique to spare normal tissue and allow dose escalation in total body irradiation (TBI). We have developed intensity-modulated radiotherapy techniques for the total marrow irradiation (TMI), total lymphatic irradiation, or total bone marrow plus lymphatic irradiation using helical tomotherapy. Methods and Materials: For TBI, we typically use 12 Gy in 10 fractions delivered at an extended source-to-surface distance (SSD). Using helical tomotherapy, it is possible to deliver equally effective doses to the bone marrow and lymphatics while sparing normal organs to a significant degree. In the TMI patients, whole body skeletal bone, including the ribs and sternum, comprise the treatment target. In the total lymphatic irradiation, the target is expanded to include the spleen and major lymph node areas. Sanctuary sites for disease (brain and testes) are included when clinically indicated. Spared organs include the lungs, esophagus, parotid glands, eyes, oral cavity, liver, kidneys, stomach, small and large intestine, bladder, and ovaries. Results: With TBI, all normal organs received the TBI dose; with TMI, total lymphatic irradiation, and total bone marrow plus lymphatic irradiation, the visceral organs are spared. For the first 6 patients treated with TMI, the median dose to organs at risk averaged 51% lower than would be achieved with TBI. By putting greater weight on the avoidance of specific organs, greater sparing was possible. Conclusion: Sparing of normal tissues and dose escalation is possible using helical tomotherapy. Late effects such as radiation pneumonitis, veno-occlusive disease, cataracts, neurocognitive effects, and the development of second tumors should be diminished in severity and frequency according to the dose reduction realized for the organs at risk

  6. The helical tomo-therapy: appeal to projects Inca 2005 first assessment of the three equipped establishments

    International Nuclear Information System (INIS)

    Zefkili, S.; Francois, P.; Giraud, P.; Caron, J.; Dejean, C.; Kantor, G.; Munos, C.; Mahe, M.A.; Lisbona, A.

    2007-01-01

    The centers of fight against cancer ( C.L.C.C.) Institute Curie of Paris, Institute Bergonie of Bordeaux, Center Rene Gauducheau of Nantes have got to exploit the helical radiotherapy (tomo-therapy) in the frame of an appeal to projects launched in 2005 by the National Institute of cancer (I.n.c.a.) in relation with the innovating techniques in radiotherapy and presenting one of the measures of the Cancer plan 2003-2007. This communication constitutes a step report in the installation and use of equipments. (N.C.)

  7. Technical Note: Output and energy fluctuations of the tomotherapy Hi-Art helical tomotherapy system

    International Nuclear Information System (INIS)

    Mahan, Stephen L.; Chase, Daniel J.; Ramsey, Chester R.

    2004-01-01

    The output and energy calibrations for the first clinical Hi-Art 2.0 helical tomotherapy system have been reviewed. Fixed-gantry/fixed-couch and rotational-gantry/fixed-couch measurements were made on a daily basis over a period of 20 weeks to investigate system stability. Static gantry measurements were taken at 10 cm depth in a rectangular stack of Virtual Water at an SSD distance of 90 cm and a field size of 5x40 cm. Rotational gantry measurements were taken in a cylindrical phantom Virtual Water phantom for a field size of 5x40 cm. The Hi-Art 2.0 system has maintained its calibration to within ±2% and energy to within ±1.5% over the initial 20 week period

  8. Verification of helical tomotherapy delivery using autoassociative kernel regression

    International Nuclear Information System (INIS)

    Seibert, Rebecca M.; Ramsey, Chester R.; Garvey, Dustin R.; Wesley Hines, J.; Robison, Ben H.; Outten, Samuel S.

    2007-01-01

    Quality assurance (QA) is a topic of major concern in the field of intensity modulated radiation therapy (IMRT). The standard of practice for IMRT is to perform QA testing for individual patients to verify that the dose distribution will be delivered to the patient. The purpose of this study was to develop a new technique that could eventually be used to automatically evaluate helical tomotherapy treatments during delivery using exit detector data. This technique uses an autoassociative kernel regression (AAKR) model to detect errors in tomotherapy delivery. AAKR is a novel nonparametric model that is known to predict a group of correct sensor values when supplied a group of sensor values that is usually corrupted or contains faults such as machine failure. This modeling scheme is especially suited for the problem of monitoring the fluence values found in the exit detector data because it is able to learn the complex detector data relationships. This scheme still applies when detector data are summed over many frames with a low temporal resolution and a variable beam attenuation resulting from patient movement. Delivery sequences from three archived patients (prostate, lung, and head and neck) were used in this study. Each delivery sequence was modified by reducing the opening time for random individual multileaf collimator (MLC) leaves by random amounts. The error and error-free treatments were delivered with different phantoms in the path of the beam. Multiple autoassociative kernel regression (AAKR) models were developed and tested by the investigators using combinations of the stored exit detector data sets from each delivery. The models proved robust and were able to predict the correct or error-free values for a projection, which had a single MLC leaf decrease its opening time by less than 10 msec. The model also was able to determine machine output errors. The average uncertainty value for the unfaulted projections ranged from 0.4% to 1.8% of the detector

  9. Parotid Gland Sparing With Helical Tomotherapy in Head-and-Neck Cancer

    International Nuclear Information System (INIS)

    Voordeckers, Mia; Farrag, Ashraf; Everaert, Hendrik; Tournel, Koen; Storme, Guy; Verellen, Dirk; De Ridder, Mark

    2012-01-01

    Purpose: This study evaluated the ability of helical tomotherapy to spare the function of the parotid glands in patients with head-and-neck cancer by analyzing dose–volume histograms, salivary gland scintigraphy, and quality of life assessment. Methods and Materials: Data from 76 consecutive patients treated with helical tomotherapy (Hi-Art Tomotherapy) at University Hospital Brussel were analyzed. During planning, priority was given to planning target volume (PTV) coverage: ≥95% of the dose must be delivered to ≥95% of the PTV. Elective nodal regions received 54 Gy (1.8 Gy/fraction). A dose of 70.5 Gy (2.35 Gy/fraction) was prescribed to the primary tumor and pathologic lymph nodes (simultaneous integrated boost scheme). Objective scoring of salivary excretion was performed by salivary gland scintigraphy. Subjective scoring of salivary gland function was evaluated by the European Organization for Research and Treatment of Cancer quality of life questionnaires Quality of Life Questionnaire—C30 (QLQ-C30) and Quality of Life Questionnaire—Head and Neck 35 (H and N35). Results: Analysis of dose–volume histograms (DVHs) showed excellent coverage of the PTV. The volume of PTV receiving 95% of the prescribed dose (V95%) was 99.4 (range, 96.3–99.9). DVH analysis of parotid gland showed a median value of the mean parotid dose of 32.1 Gy (range, 17.5–70.3 Gy). The median parotid volume receiving a dose <26 Gy was 51.2%. Quality of life evaluation demonstrated an initial deterioration of almost all scales and items in QLQ-C30 and QLQ-H and N35. Most items improved in time, and some reached baseline values 18 months after treatment. Conclusion: DVH analysis, scintigraphic evaluation of parotid function, and quality of life assessment of our patient group showed that helical tomotherapy makes it possible to preserve parotid gland function without compromising disease control. We recommend mean parotid doses of <34 Gy and doses <26 Gy to a maximum 47% of the

  10. Helical tomotherapy shielding calculation for an existing LINAC treatment room: sample calculation and cautions

    International Nuclear Information System (INIS)

    Wu Chuan; Guo Fanqing; Purdy, James A

    2006-01-01

    This paper reports a step-by-step shielding calculation recipe for a helical tomotherapy unit (TomoTherapy Inc., Madison, WI, USA), recently installed in an existing Varian 600C treatment room. Both primary and secondary radiations (leakage and scatter) are explicitly considered. A typical patient load is assumed. Use factor is calculated based on an analytical formula derived from the tomotherapy rotational beam delivery geometry. Leakage and scatter are included in the calculation based on corresponding measurement data as documented by TomoTherapy Inc. Our calculation result shows that, except for a small area by the therapists' console, most of the existing Varian 600C shielding is sufficient for the new tomotherapy unit. This work cautions other institutions facing the similar situation, where an HT unit is considered for an existing LINAC treatment room, more secondary shielding might be considered at some locations, due to the significantly increased secondary shielding requirement by HT. (note)

  11. Should helical tomotherapy replace brachytherapy for cervical cancer? Case report.

    Science.gov (United States)

    Hsieh, Chen-Hsi; Wei, Ming-Chow; Hsu, Yao-Peng; Chong, Ngot-Swan; Chen, Yu-Jen; Hsiao, Sheng-Mou; Hsieh, Yen-Ping; Wang, Li-Ying; Shueng, Pei-Wei

    2010-11-23

    Stereotactic body radiation therapy (SBRT) administered via a helical tomotherapy (HT) system is an effective modality for treating lung cancer and metastatic liver tumors. Whether SBRT delivered via HT is a feasible alternative to brachytherapy in treatment of locally advanced cervical cancer in patients with unusual anatomic configurations of the uterus has never been studied. A 46-year-old woman presented with an 8-month history of abnormal vaginal bleeding. Biopsy revealed squamous cell carcinoma of the cervix. Magnetic resonance imaging (MRI) showed a cervical tumor with direct invasion of the right parametrium, bilateral hydronephrosis, and multiple uterine myomas. International Federation of Gynecology and Obstetrics (FIGO) stage IIIB cervical cancer was diagnosed. Concurrent chemoradiation therapy (CCRT) followed by SBRT delivered via HT was administered instead of brachytherapy because of the presence of multiple uterine myomas with bleeding tendency. Total abdominal hysterectomy was performed after 6 weeks of treatment because of the presence of multiple uterine myomas. Neither pelvic MRI nor results of histopathologic examination at X-month follow-up showed evidence of tumor recurrence. Only grade 1 nausea and vomiting during treatment were noted. Lower gastrointestinal bleeding was noted at 14-month follow-up. No fistula formation and no evidence of haematological, gastrointestinal or genitourinary toxicities were noted on the most recent follow-up. CCRT followed by SBRT appears to be an effective and safe modality for treatment of cervical cancer. Larger-scale studies are warranted.

  12. Should helical tomotherapy replace brachytherapy for cervical cancer? Case report

    Directory of Open Access Journals (Sweden)

    Chen Yu-Jen

    2010-11-01

    Full Text Available Abstract Background Stereotactic body radiation therapy (SBRT administered via a helical tomotherapy (HT system is an effective modality for treating lung cancer and metastatic liver tumors. Whether SBRT delivered via HT is a feasible alternative to brachytherapy in treatment of locally advanced cervical cancer in patients with unusual anatomic configurations of the uterus has never been studied. Case Presentation A 46-year-old woman presented with an 8-month history of abnormal vaginal bleeding. Biopsy revealed squamous cell carcinoma of the cervix. Magnetic resonance imaging (MRI showed a cervical tumor with direct invasion of the right parametrium, bilateral hydronephrosis, and multiple uterine myomas. International Federation of Gynecology and Obstetrics (FIGO stage IIIB cervical cancer was diagnosed. Concurrent chemoradiation therapy (CCRT followed by SBRT delivered via HT was administered instead of brachytherapy because of the presence of multiple uterine myomas with bleeding tendency. Total abdominal hysterectomy was performed after 6 weeks of treatment because of the presence of multiple uterine myomas. Neither pelvic MRI nor results of histopathologic examination at X-month follow-up showed evidence of tumor recurrence. Only grade 1 nausea and vomiting during treatment were noted. Lower gastrointestinal bleeding was noted at 14-month follow-up. No fistula formation and no evidence of haematological, gastrointestinal or genitourinary toxicities were noted on the most recent follow-up. Conclusions CCRT followed by SBRT appears to be an effective and safe modality for treatment of cervical cancer. Larger-scale studies are warranted.

  13. Should helical tomotherapy replace brachytherapy for cervical cancer? Case report

    International Nuclear Information System (INIS)

    Hsieh, Chen-Hsi; Wei, Ming-Chow; Hsu, Yao-Peng; Chong, Ngot-Swan; Chen, Yu-Jen; Hsiao, Sheng-Mou; Hsieh, Yen-Ping; Wang, Li-Ying; Shueng, Pei-Wei

    2010-01-01

    Stereotactic body radiation therapy (SBRT) administered via a helical tomotherapy (HT) system is an effective modality for treating lung cancer and metastatic liver tumors. Whether SBRT delivered via HT is a feasible alternative to brachytherapy in treatment of locally advanced cervical cancer in patients with unusual anatomic configurations of the uterus has never been studied. A 46-year-old woman presented with an 8-month history of abnormal vaginal bleeding. Biopsy revealed squamous cell carcinoma of the cervix. Magnetic resonance imaging (MRI) showed a cervical tumor with direct invasion of the right parametrium, bilateral hydronephrosis, and multiple uterine myomas. International Federation of Gynecology and Obstetrics (FIGO) stage IIIB cervical cancer was diagnosed. Concurrent chemoradiation therapy (CCRT) followed by SBRT delivered via HT was administered instead of brachytherapy because of the presence of multiple uterine myomas with bleeding tendency. Total abdominal hysterectomy was performed after 6 weeks of treatment because of the presence of multiple uterine myomas. Neither pelvic MRI nor results of histopathologic examination at X-month follow-up showed evidence of tumor recurrence. Only grade 1 nausea and vomiting during treatment were noted. Lower gastrointestinal bleeding was noted at 14-month follow-up. No fistula formation and no evidence of haematological, gastrointestinal or genitourinary toxicities were noted on the most recent follow-up. CCRT followed by SBRT appears to be an effective and safe modality for treatment of cervical cancer. Larger-scale studies are warranted

  14. Dose-escalated simultaneous integrated-boost treatment of prostate cancer patients via helical tomotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Geier, M.; Astner, S.T.; Duma, M.N.; Putzhammer, J.; Winkler, C.; Molls, M.; Geinitz, H. [Technische Univ. Muenchen (Germany). Klinik und Poliklinik fuer Strahlentherapie und Radiologische Onkologie; Jacob, V. [Universitaetsklinikum Freiburg (Germany). Klinik fuer Strahlenheilkunde; Nieder, C. [Nordland Hospital, Bodoe (Norway). Dept. of Oncology and Palliative Care; Tromsoe Univ. (Norway). Inst. of Clinical Medicine

    2012-05-15

    The goal of this work was to assess the feasibility of moderately hypofractionated simultaneous integrated-boost intensity-modulated radiotherapy (SIB-IMRT) with helical tomotherapy in patients with localized prostate cancer regarding acute side effects and dose-volume histogram data (DVH data). Acute side effects and DVH data were evaluated of the first 40 intermediate risk prostate cancer patients treated with a definitive daily image-guided SIB-IMRT protocol via helical tomotherapy in our department. The planning target volume including the prostate and the base of the seminal vesicles with safety margins was treated with 70 Gy in 35 fractions. The boost volume containing the prostate and 3 mm safety margins (5 mm craniocaudal) was treated as SIB to a total dose of 76 Gy (2.17 Gy per fraction). Planning constraints for the anterior rectal wall were set in order not to exceed the dose of 76 Gy prescribed to the boost volume. Acute toxicity was evaluated prospectively using a modified CTCAE (Common Terminology Criteria for Adverse Events) score. SIB-IMRT allowed good rectal sparing, although the full boost dose was permitted to the anterior rectal wall. Median rectum dose was 38 Gy in all patients and the median volumes receiving at least 65 Gy (V65), 70 Gy (V70), and 75 Gy (V75) were 13.5%, 9%, and 3%, respectively. No grade 4 toxicity was observed. Acute grade 3 toxicity was observed in 20% of patients involving nocturia only. Grade 2 acute intestinal and urological side effects occurred in 25% and 57.5%, respectively. No correlation was found between acute toxicity and the DVH data. This institutional SIB-IMRT protocol using daily image guidance as a precondition for smaller safety margins allows dose escalation to the prostate without increasing acute toxicity. (orig.)

  15. Whole brain helical Tomotherapy with integrated boost for brain metastases in patients with malignant melanoma–a randomized trial

    International Nuclear Information System (INIS)

    Hauswald, Henrik; Habl, Gregor; Krug, David; Kehle, Denise; Combs, Stephanie E; Bermejo, Justo Lorenzo; Debus, Jürgen; Sterzing, Florian

    2013-01-01

    Patients with malignant melanoma may develop brain metastases during the course of the disease, requiring radiotherapeutic treatment. In patients with 1–3 brain metastases, radiosurgery has been established as a treatment option besides surgery. For patients with 4 or more brain metastases, whole brain radiotherapy is considered the standard treatment. In certain patients with brain metastases, radiation treatment using whole brain helical Tomotherapy with integrated boost and hippocampal-sparing may improve prognosis of these patients. The present prospective, randomized two-armed trial aims to exploratory investigate the treatment response to conventional whole brain radiotherapy applying 30 Gy in 10 fractions versus whole brain helical Tomotherapy applying 30 Gy in 10 fractions with an integrated boost of 50 Gy to the brain metastases as well as hippocampal-sparing in patients with brain metastases from malignant melanoma. The main inclusion criteria include magnetic resonance imaging confirmed brain metastases from a histopathologically confirmed malignant melanoma in patients with a minimum age of 18 years. The main exclusion criteria include a previous radiotherapy of the brain and not having recovered from acute high-grade toxicities of prior therapies. The primary endpoint is treatment-related toxicity. Secondary endpoints include imaging response, local and loco-regional progression-free survival, overall survival and quality of life

  16. Clinic results of 121 nasopharyngeal carcinoma patients treated by helical tomotherapy

    International Nuclear Information System (INIS)

    Du Lei; Ma Lin; Feng Linchun; Zhou Guixia; Qu Baolin; Ren Gang; Xu Shouping; Xie Chuanbin; Zhang Xinxin; Li Fang

    2012-01-01

    Objective: To summarize the outcome of nasopharyngeal carcinoma (NPC) treated by helical tomotherapy in the Chinese PLA general hospital. Methods: Between September 2007 and August 2010, 121 newly diagnosed NPC patients were treated by radiotherapy with Tomotherapy system, with (n =90) or without (n = 31) concurrent chemotherapy or molecular target therapy. The prescription dose was 70 - 74 Gy/33f to primary tumor and positive lymph node planning target volume, 60.0 - 62.7 Gy/33f to high risk planning target volume, and 52 -56 Gy/33f to low risk planning target volume. Acute side-effects were evaluated with RTOG/EORTC criteria. Results: The remission rate of primary lesion and positive lymph nodes was 95.0% and 99.0%, respectively. The follow-up rate was 100%. The number of patients with 1, 2 and 3 years followed-up were 99, 49, and 7. The 1-, 2-and 3-year local relapse-free survival rates were 97.30%, 97.3% and 97.3%, respectively. The 1-, 2-and 3-year nodal relapse-free survival rates were 100%, 100% and 100%, respectively. The 1-, 2-and 3-year distant metastasis-free survival rates were 98.4%, 96.3% and 96.3%, respectively. The 1-, 2-and 3-year overall survival rates were 96.5%, 92.6% and 86.8%, respectively. Acute toxicities of skin, oral mucosa and xerostomia with grade 0, 1, 2 and 3 were 5.0%, 74.4%, 15.7% and 4.9%; 0.8%, 37.2%, 57.9% and 4.1%; 3.3%, 53.7%, 43.0% and 0%, respectively. Xerostomia restored with time, no grade 2 or more xerostomia was observed 1 year after radiation therapy. Concurrent chemotherapy significantly increased incidence of mucositis, esophagitis and tracheitis. Conclusion: Helical tomotherapy is efficient, secure and effective modality for the treatment of nasopharyngeal carcinoma. (authors)

  17. Helical Tomotherapy in Children and Adolescents: Dosimetric Comparisons, Opportunities and Issues

    Energy Technology Data Exchange (ETDEWEB)

    Mascarin, Maurizio, E-mail: mascarin@cro.it [Pediatric Radiotherapy Unit, Centro di Riferimento Oncologico- National Cancer Institute/Via Franco Gallini, 2 33081 Aviano (PN) (Italy); Department of Radiation Therapy, Centro di Riferimento Oncologico- National Cancer Institute/Via Franco Gallini, 2 33081 Aviano (PN) (Italy); Giugliano, Francesca Maria [Pediatric Radiotherapy Unit, Centro di Riferimento Oncologico- National Cancer Institute/Via Franco Gallini, 2 33081 Aviano (PN) (Italy); Seconda Università di Napoli, Napoli 80138 (Italy); Coassin, Elisa [Pediatric Radiotherapy Unit, Centro di Riferimento Oncologico- National Cancer Institute/Via Franco Gallini, 2 33081 Aviano (PN) (Italy); Drigo, Annalisa; Chiovati, Paola; Dassie, Andrea [Department of Radiation Therapy, Centro di Riferimento Oncologico- National Cancer Institute/Via Franco Gallini, 2 33081 Aviano (PN) (Italy); Department of Medical Physics, Centro di Riferimento Oncologico- National Cancer Institute/Via Franco Gallini, 2 33081 Aviano (PN) (Italy); Franchin, Giovanni; Minatel, Emilio; Trovò, Mauro Gaetano [Department of Radiation Therapy, Centro di Riferimento Oncologico- National Cancer Institute/Via Franco Gallini, 2 33081 Aviano (PN) (Italy)

    2011-10-25

    Helical Tomotherapy (HT) is a highly conformal image-guided radiation technique, introduced into clinical routine in 2006 at the Centro di Riferimento Oncologico Aviano (Italy). With this new technology, intensity-modulated radiotherapy (IMRT) is delivered using a helicoidal method. Here we present our dosimetric experiences using HT in 100 children, adolescents and young adults treated from May 2006 to February 2011. The median age of the patients was 13 years (range 1–24). The most common treated site was the central nervous system (50; of these, 24 were craniospinal irradiations), followed by thorax (22), head and neck (10), abdomen and pelvis (11), and limbs (7). The use of HT was calculated in accordance to the target dose conformation, the target size and shape, the dose to critical organs adjacent to the target, simultaneous treatment of multiple targets, and re-irradiation. HT has demonstrated to improve target volume dose homogeneity and the sparing of critical structures, when compared to 3D Linac-based radiotherapy (RT). In standard cases this technique represented a comparable alternative to IMRT delivered with conventional linear accelerator. In certain cases (e.g., craniospinal and pleural treatments) only HT generated adequate treatment plans with good target volume coverage. However, the gain in target conformality should be balanced with the spread of low-doses to distant areas. This remains an open issue for the potential risk of secondary malignancies (SMNs) and longer follow-up is mandatory.

  18. Integral dose delivered to normal brain with conventional intensity-modulated radiotherapy (IMRT) and helical tomotherapy IMRT during partial brain radiotherapy for high-grade gliomas with and without selective sparing of the hippocampus, limbic circuit and neural stem cell compartment

    International Nuclear Information System (INIS)

    Marsh, James C.; Ziel, Ellis G; Diaz, Aidnag Z; Turian, Julius V; Wendt, Julie A.; Gobole, Rohit

    2013-01-01

    We compared integral dose with uninvolved brain (ID brain ) during partial brain radiotherapy (PBRT) for high-grade glioma patients using helical tomotherapy (HT) and seven field traditional inverse-planned intensity-modulated radiotherapy (IMRT) with and without selective sparing (SPA) of contralateral hippocampus, neural stem cell compartment (NSC) and limbic circuit. We prepared four PBRT treatment plans for four patients with high-grade gliomas (60Gy in 30 fractions delivered to planning treatment volume (PTV60Gy)). For all plans, a structure denoted 'uninvolved brain' was created, which included all brain tissue not part of PTV or standard (STD) organs at risk (OAR). No dosimetric constraints were included for uninvolved brain. Selective SPA plans were prepared with IMRT and HT; contralateral hippocampus, NSC and limbic circuit were contoured; and dosimetric constraints were entered for these structures without compromising dose to PTV or STD OAR. We compared V100 and D95 for PTV46Gy and PTV60Gy, and ID brain for all plans. There were no significant differences in V100 and D95 for PTV46Gy and PTV60Gy. ID brain was lower in traditional IMRT versus HT plans for STD and SPA plans (mean ID brain 23.64Gy vs. 28Gy and 18.7Gy vs. 24.5Gy, respectively) and in SPA versus STD plans both with IMRT and HT (18.7Gy vs. 23.64Gy and 24.5Gy vs. 28Gy, respectively). n the setting of PBRT for high-grade gliomas, IMRT reduces ID brain compared with HT with or without selective SPA of contralateral hippocampus, limbic circuit and NSC, and the use of selective SPA reduces ID brain compared with STD PBRT delivered with either traditional IMRT or HT.

  19. Feasibility study of multi-pass respiratory-gated helical tomotherapy of a moving target via binary MLC closure

    Science.gov (United States)

    Kim, Bryan; Chen, Jeff; Kron, Tomas; Battista, Jerry

    2010-11-01

    Gated radiotherapy of lung lesions is particularly complex for helical tomotherapy, due to the simultaneous motions of its three subsystems (gantry, couch and collimator). We propose a new way to implement gating for helical tomotherapy, namely multi-pass respiratory gating. In this method, gating is achieved by delivering only the beam projections that occur within a respiratory gating window, while blocking the rest of the beam projections by fully closing all collimator leaves. Due to the continuous couch motion, the planned beam projections must be delivered over multiple passes of radiation deliveries. After each pass, the patient couch is reset to its starting position, and the treatment recommences at a different phase of tumour motion to 'fill in' the previously blocked beam projections. The gating process may be repeated until the plan dose is delivered (full gating), or halted after a certain number of passes, with the entire remaining dose delivered in a final pass without gating (partial gating). The feasibility of the full gating approach was first tested for sinusoidal target motion, through experimental measurements with film and computer simulation. The optimal gating parameters for full and partial gating methods were then determined for various fractionation schemes through computer simulation, using a patient respiratory waveform. For sinusoidal motion, the PTV dose deviations of -29 to 5% observed without gating were reduced to range from -1 to 3% for a single fraction, with a 4 pass full gating. For a patient waveform, partial gating required fewer passes than full gating for all fractionation schemes. For a single fraction, the maximum allowed residual motion was only 4 mm, requiring large numbers of passes for both full (12) and partial (7 + 1) gating methods. The number of required passes decreased significantly for 3 and 30 fractions, allowing residual motion up to 7 mm. Overall, the multi-pass gating technique was shown to be a promising

  20. Prospective Phase I-II Trial of Helical Tomotherapy With or Without Chemotherapy for Postoperative Cervical Cancer Patients

    International Nuclear Information System (INIS)

    Schwarz, Julie K.; Wahab, Sasa; Grigsby, Perry W.

    2011-01-01

    Purpose: To investigate, in a prospective trial, the acute and chronic toxicity of patients with cervical cancer treated with surgery and postoperative intensity-modulated radiotherapy (RT) delivered using helical tomotherapy, with or without the administration of concurrent chemotherapy. Patients and Methods: A total of 24 evaluable patients entered the study between March 2006 and August 2009. The indications for postoperative RT were tumor size, lymphovascular space invasion, and the depth of cervical stromal invasion in 15 patients; 9 patients underwent postoperative RT because of surgically positive lymph nodes. All patients underwent pelvic RT delivered with helical tomotherapy and intracavitary high-dose-rate brachytherapy. Treatment consisted of concurrent weekly platinum in 17, sequential carboplatin/Taxol in 1, and RT alone in 6. The patients were monitored for acute and chronic toxicity using the Common Toxicity Criteria, version 3.0. Results: The median follow-up was 24 months (range, 4–49). At the last follow-up visit, 23 patients were alive and disease free. Of the 24 patients, 12 (50%) experienced acute Grade 3 gastrointestinal toxicity (anorexia in 5, diarrhea in 4, and nausea in 3). One patient developed acute Grade 4 genitourinary toxicity (vesicovaginal fistula). For patients treated with concurrent chemotherapy, the incidence of acute Grade 3 and 4 hematologic toxicity was 71% and 24%, respectively. For patients treated without concurrent chemotherapy, the incidence of acute Grade 3 and 4 hematologic toxicity was 29% and 14%, respectively. Two long-term toxicities occurred (vesicovaginal fistula at 25 months and small bowel obstruction at 30 months). The overall and progression-free survival rate at 3 years for all patients was 100% and 89%, respectively. Conclusion: The results of our study have shown that postoperative external RT for cervical cancer delivered with helical tomotherapy and high-dose-rate brachytherapy and with or without

  1. Feasibility study of multi-pass respiratory-gated helical tomotherapy of a moving target via binary MLC closure

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Bryan; Chen, Jeff; Battista, Jerry [London Regional Cancer Program, London Health Sciences Centre, London, ON (Canada); Kron, Tomas, E-mail: bryan.kim@lhsc.on.c [Peter MacCallum Cancer Center, Melbourne (Australia)

    2010-11-21

    Gated radiotherapy of lung lesions is particularly complex for helical tomotherapy, due to the simultaneous motions of its three subsystems (gantry, couch and collimator). We propose a new way to implement gating for helical tomotherapy, namely multi-pass respiratory gating. In this method, gating is achieved by delivering only the beam projections that occur within a respiratory gating window, while blocking the rest of the beam projections by fully closing all collimator leaves. Due to the continuous couch motion, the planned beam projections must be delivered over multiple passes of radiation deliveries. After each pass, the patient couch is reset to its starting position, and the treatment recommences at a different phase of tumour motion to 'fill in' the previously blocked beam projections. The gating process may be repeated until the plan dose is delivered (full gating), or halted after a certain number of passes, with the entire remaining dose delivered in a final pass without gating (partial gating). The feasibility of the full gating approach was first tested for sinusoidal target motion, through experimental measurements with film and computer simulation. The optimal gating parameters for full and partial gating methods were then determined for various fractionation schemes through computer simulation, using a patient respiratory waveform. For sinusoidal motion, the PTV dose deviations of -29 to 5% observed without gating were reduced to range from -1 to 3% for a single fraction, with a 4 pass full gating. For a patient waveform, partial gating required fewer passes than full gating for all fractionation schemes. For a single fraction, the maximum allowed residual motion was only 4 mm, requiring large numbers of passes for both full (12) and partial (7 + 1) gating methods. The number of required passes decreased significantly for 3 and 30 fractions, allowing residual motion up to 7 mm. Overall, the multi-pass gating technique was shown to be a

  2. Prospective Phase I-II Trial of Helical Tomotherapy With or Without Chemotherapy for Postoperative Cervical Cancer Patients

    Energy Technology Data Exchange (ETDEWEB)

    Schwarz, Julie K., E-mail: jschwarz@radonc.wustl.edu [Department of Radiation Oncology, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO (United States); Department of Cell Biology and Physiology, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO (United States); Alvin J. Siteman Cancer Center, Washington University School of Medicine, St. Louis, MO (United States); Wahab, Sasa [Cobb Center for Radiation Oncology Center, Austell, GA (United States); Grigsby, Perry W. [Department of Radiation Oncology, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO (United States); Alvin J. Siteman Cancer Center, Washington University School of Medicine, St. Louis, MO (United States); Division of Nuclear Medicine, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO (United States); Department of Obstetrics and Gynecology, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO (United States)

    2011-12-01

    Purpose: To investigate, in a prospective trial, the acute and chronic toxicity of patients with cervical cancer treated with surgery and postoperative intensity-modulated radiotherapy (RT) delivered using helical tomotherapy, with or without the administration of concurrent chemotherapy. Patients and Methods: A total of 24 evaluable patients entered the study between March 2006 and August 2009. The indications for postoperative RT were tumor size, lymphovascular space invasion, and the depth of cervical stromal invasion in 15 patients; 9 patients underwent postoperative RT because of surgically positive lymph nodes. All patients underwent pelvic RT delivered with helical tomotherapy and intracavitary high-dose-rate brachytherapy. Treatment consisted of concurrent weekly platinum in 17, sequential carboplatin/Taxol in 1, and RT alone in 6. The patients were monitored for acute and chronic toxicity using the Common Toxicity Criteria, version 3.0. Results: The median follow-up was 24 months (range, 4-49). At the last follow-up visit, 23 patients were alive and disease free. Of the 24 patients, 12 (50%) experienced acute Grade 3 gastrointestinal toxicity (anorexia in 5, diarrhea in 4, and nausea in 3). One patient developed acute Grade 4 genitourinary toxicity (vesicovaginal fistula). For patients treated with concurrent chemotherapy, the incidence of acute Grade 3 and 4 hematologic toxicity was 71% and 24%, respectively. For patients treated without concurrent chemotherapy, the incidence of acute Grade 3 and 4 hematologic toxicity was 29% and 14%, respectively. Two long-term toxicities occurred (vesicovaginal fistula at 25 months and small bowel obstruction at 30 months). The overall and progression-free survival rate at 3 years for all patients was 100% and 89%, respectively. Conclusion: The results of our study have shown that postoperative external RT for cervical cancer delivered with helical tomotherapy and high-dose-rate brachytherapy and with or without

  3. QA for helical tomotherapy: Report of the AAPM Task Group 148

    Energy Technology Data Exchange (ETDEWEB)

    Langen, Katja M.; Papanikolaou, Niko; Balog, John; Crilly, Richard; Followill, David; Goddu, S. Murty; Grant, Walter III; Olivera, Gustavo; Ramsey, Chester R.; Shi Chengyu [Department of Radiation Oncology, M. D. Anderson Cancer Center Orlando, Orlando, Florida 32806 (United States); Department of Radiation Oncology, Cancer Therapy and Research Center, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229 (United States); Mohawk Valley Medical Physics, Rome, New York 13440 (United States); Department of Radiation Medicine, Oregon Health and Science University, Portland, Oregon 97239 (United States); Section of Outreach Physics, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030 (United States); Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri 63110 (United States); Department of Radiology/Section of Radiation Oncology, Baylor College of Medicine, Methodist Hospital, Houston, Texas 77030 (United States); TomoTherapy, Inc., Madison, Wisconsin 53717 and Department of Medical Physics, University of Wisconsin, Madison, Wisconsin 53706 (United States); Thompson Cancer Survival Center, Knoxville, Tennessee 37916 (United States); Department of Radiation Oncology, Cancer Therapy and Research Center, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229 (United States)

    2010-09-15

    Helical tomotherapy is a relatively new modality with integrated treatment planning and delivery hardware for radiation therapy treatments. In view of the uniqueness of the hardware design of the helical tomotherapy unit and its implications in routine quality assurance, the Therapy Physics Committee of the American Association of Physicists in Medicine commissioned Task Group 148 to review this modality and make recommendations for quality assurance related methodologies. The specific objectives of this Task Group are: (a) To discuss quality assurance techniques, frequencies, and tolerances and (b) discuss dosimetric verification techniques applicable to this unit. This report summarizes the findings of the Task Group and aims to provide the practicing clinical medical physicist with the insight into the technology that is necessary to establish an independent and comprehensive quality assurance program for a helical tomotherapy unit. The emphasis of the report is to describe the rationale for the proposed QA program and to provide example tests that can be performed, drawing from the collective experience of the task group members and the published literature. It is expected that as technology continues to evolve, so will the test procedures that may be used in the future to perform comprehensive quality assurance for helical tomotherapy units.

  4. Measurement and correction of leaf open times in helical tomotherapy

    International Nuclear Information System (INIS)

    Sevillano, David; Mínguez, Cristina; Sánchez, Alicia; Sánchez-Reyes, Alberto

    2012-01-01

    Purpose: The binary multileaf collimator (MLC) is one of the most important components in helical tomotherapy (HT), as it modulates the dose delivered to the patient. However, methods to ensure MLC quality in HT treatments are lacking. The authors obtained data on the performance of the MLC in treatments administered in their department in order to assess possible delivery errors due to the MLC. Correction methods based on their data are proposed. Methods: Twenty sinograms from treatments delivered using both of the authors HT systems were measured and analyzed by recording the fluence collected by the imaging detector. Planned and actual sinograms were compared using distributions of leaf open time (LOT) errors, as well as differences in fluence reconstructed at each of the 51 projections into which the treatment planning system divides each rotation for optimization purposes. They proposed and applied a method based on individual leaf error correction and the increase in projection time to prevent latency effects when LOT is close to projection time. In order to analyze the dosimetric impact of the corrections, inphantom measurements were made for four corrected treatments. Results: The LOTs measured were consistent with those planned. Most of the mean errors in LOT distributions were within 1 ms with standard deviations of over 4 ms. Reconstructed fluences showed good results, with over 90% of points passing the 3% criterion, except in treatments with a short mean LOT, where the percentage of passing points was as low as 66%. Individual leaf errors were as long as 4 ms in some cases. Corrected sinograms improved error distribution, with standard deviations of over 3 ms and increased percentages of points passing 3% in the fluence per angle analysis, especially in treatments with a short mean LOT and those that were more subject to latency effects. The minimum percentage of points within 3% increased to 86%. In-phantom measurements of the corrected treatments

  5. Measurement and correction of leaf open times in helical tomotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Sevillano, David; Minguez, Cristina; Sanchez, Alicia; Sanchez-Reyes, Alberto [Department of Medical Physics, Tomotherapy Unit, Grupo IMO, Madrid 28010 (Spain)

    2012-11-15

    Purpose: The binary multileaf collimator (MLC) is one of the most important components in helical tomotherapy (HT), as it modulates the dose delivered to the patient. However, methods to ensure MLC quality in HT treatments are lacking. The authors obtained data on the performance of the MLC in treatments administered in their department in order to assess possible delivery errors due to the MLC. Correction methods based on their data are proposed. Methods: Twenty sinograms from treatments delivered using both of the authors HT systems were measured and analyzed by recording the fluence collected by the imaging detector. Planned and actual sinograms were compared using distributions of leaf open time (LOT) errors, as well as differences in fluence reconstructed at each of the 51 projections into which the treatment planning system divides each rotation for optimization purposes. They proposed and applied a method based on individual leaf error correction and the increase in projection time to prevent latency effects when LOT is close to projection time. In order to analyze the dosimetric impact of the corrections, inphantom measurements were made for four corrected treatments. Results: The LOTs measured were consistent with those planned. Most of the mean errors in LOT distributions were within 1 ms with standard deviations of over 4 ms. Reconstructed fluences showed good results, with over 90% of points passing the 3% criterion, except in treatments with a short mean LOT, where the percentage of passing points was as low as 66%. Individual leaf errors were as long as 4 ms in some cases. Corrected sinograms improved error distribution, with standard deviations of over 3 ms and increased percentages of points passing 3% in the fluence per angle analysis, especially in treatments with a short mean LOT and those that were more subject to latency effects. The minimum percentage of points within 3% increased to 86%. In-phantom measurements of the corrected treatments

  6. Helical tomotherapy with dynamic running-start-stop delivery compared to conventional tomotherapy delivery

    Energy Technology Data Exchange (ETDEWEB)

    Rong, Yi, E-mail: yi.rong@osumc.edu [Department of Radiation Oncology, The Ohio State University Wexner Medical Center, Columbus, Ohio 43210 (United States); Chen, Yu; Lu, Weiguo [21st Century Oncology, Madison, Wisconsin 53719 (United States); Shang, Lu [Guangxi Polytechnic of Construction and Technology, Nanning (China); Zuo, Li [Radiologic Sciences and Respiratory Therapy Division, School of Health and Rehabilitation Sciences, The Ohio State University College of Medicine, Columbus, Ohio 43210 (United States); Chen, Quan [Department of Radiation Oncology, University of Virginia, Charlottesville, Virginia 22904 (United States)

    2014-05-15

    Purpose: Despite superior target dose uniformity, helical tomotherapy{sup ®} (HT) may involve a trade-off between longitudinal dose conformity and beam-on time (BOT), due to the limitation of only three available jaw sizes with the conventional HT (1.0, 2.5, and 5.0 cm). The recently introduced dynamic running-start-stop (RSS) delivery allows smaller jaw opening at the superior and inferior ends of the target when a sharp penumbra is needed. This study compared the dosimetric performance of RSS delivery with the fixed jaw HT delivery. Methods: Twenty patient cases were selected and deidentified prior to treatment planning, including 16 common clinical cases (brain, head and neck (HN), lung, and prostate) and four special cases of whole brain with hippocampus avoidance (WBHA) that require a high degree of dose modulation. HT plans were generated for common clinical cases using the fixed 2.5 cm jaw width (HT2.5) and WBHA cases using 1.0 cm (HT1.0). The jaw widths for RSS were preset with a larger size (RSS5.0 vs HT2.5 and RSS2.5 vs HT1.0). Both delivery techniques were planned based on identical contours, prescriptions, and planning objectives. Dose indices for targets and critical organs were compared using dose-volume histograms, BOT, and monitor units. Results: The average BOT was reduced from 4.8 min with HT2.5 to 2.5 min with RSS5.0. Target dose homogeneity with RSS5.0 was shown comparable to HT2.5 for common clinical sites. Superior normal tissue sparing was observed in RSS5.0 for optic nerves and optic chiasm in brain and HN cases. RSS5.0 demonstrated improved dose sparing for cord and esophagus in lung cases, as well as penile bulb in prostate cases. The mean body dose was comparable for both techniques. For the WBHA cases, the target homogeneity was significantly degraded in RSS2.5 without distinct dose sparing for hippocampus, compared to HT1.0. Conclusions: Compared to the fixed jaw HT delivery, RSS combined with a larger jaw width provides faster

  7. Helical tomotherapy with dynamic running-start-stop delivery compared to conventional tomotherapy delivery

    International Nuclear Information System (INIS)

    Rong, Yi; Chen, Yu; Lu, Weiguo; Shang, Lu; Zuo, Li; Chen, Quan

    2014-01-01

    Purpose: Despite superior target dose uniformity, helical tomotherapy ® (HT) may involve a trade-off between longitudinal dose conformity and beam-on time (BOT), due to the limitation of only three available jaw sizes with the conventional HT (1.0, 2.5, and 5.0 cm). The recently introduced dynamic running-start-stop (RSS) delivery allows smaller jaw opening at the superior and inferior ends of the target when a sharp penumbra is needed. This study compared the dosimetric performance of RSS delivery with the fixed jaw HT delivery. Methods: Twenty patient cases were selected and deidentified prior to treatment planning, including 16 common clinical cases (brain, head and neck (HN), lung, and prostate) and four special cases of whole brain with hippocampus avoidance (WBHA) that require a high degree of dose modulation. HT plans were generated for common clinical cases using the fixed 2.5 cm jaw width (HT2.5) and WBHA cases using 1.0 cm (HT1.0). The jaw widths for RSS were preset with a larger size (RSS5.0 vs HT2.5 and RSS2.5 vs HT1.0). Both delivery techniques were planned based on identical contours, prescriptions, and planning objectives. Dose indices for targets and critical organs were compared using dose-volume histograms, BOT, and monitor units. Results: The average BOT was reduced from 4.8 min with HT2.5 to 2.5 min with RSS5.0. Target dose homogeneity with RSS5.0 was shown comparable to HT2.5 for common clinical sites. Superior normal tissue sparing was observed in RSS5.0 for optic nerves and optic chiasm in brain and HN cases. RSS5.0 demonstrated improved dose sparing for cord and esophagus in lung cases, as well as penile bulb in prostate cases. The mean body dose was comparable for both techniques. For the WBHA cases, the target homogeneity was significantly degraded in RSS2.5 without distinct dose sparing for hippocampus, compared to HT1.0. Conclusions: Compared to the fixed jaw HT delivery, RSS combined with a larger jaw width provides faster treatment

  8. Comparison of IMRT Treatment Plans Between Linac and Helical Tomotherapy Based on Integral Dose and Inhomogeneity Index

    International Nuclear Information System (INIS)

    Shi Chengyu; Penagaricano, Jose; Papanikolaou, Niko

    2008-01-01

    Intensity modulated radiotherapy (IMRT) is an advanced treatment technology for radiation therapy. There are several treatment planning systems (TPS) that can generate IMRT plans. These plans may show different inhomogeneity indices to the planning target volume (PTV) and integral dose to organs at risk (OAR). In this study, we compared clinical cases covering different anatomical treatment sites, including head and neck, brain, lung, prostate, pelvis, and cranio-spinal axis. Two treatment plans were developed for each case using Pinnacle 3 and helical tomotherapy (HT) TPS. The inhomogeneity index of the PTV and the non-tumor integral dose (NTID) were calculated and compared for each case. Despite the difference in the number of effective beams, in several cases, NTID did not increase from HT as compared to the step-and-shoot delivery method. Six helical tomotherapy treatment plans for different treatment sites have been analyzed and compared against corresponding step-and-shoot plans generated with the Pinnacle 3 planning system. Results show that HT may produce plans with smaller integral doses to healthy organs, and fairly homogeneous doses to the target as compared to linac-based step-and-shoot IMRT planning in special treatment site such as cranio-spinal

  9. Whole pelvic helical tomotherapy for locally advanced cervical cancer: technical implementation of IMRT with helical tomothearapy

    International Nuclear Information System (INIS)

    Hsieh, Chen-Hsi; Shueng, Pei-Wei; Wei, Ming-Chow; Lee, Hsing-Yi; Hsiao, Sheng-Mou; Chen, Chien-An; Wang, Li-Ying; Hsieh, Yen-Ping; Tsai, Tung-Hu; Chen, Yu-Jen

    2009-01-01

    To review the experience and to evaluate the treatment plan of using helical tomotherapy (HT) for the treatment of cervical cancer. Between November 1st, 2006 and May 31, 2009, 10 cervical cancer patients histologically confirmed were enrolled. All of the patients received definitive concurrent chemoradiation (CCRT) with whole pelvic HT (WPHT) followed by brachytherapy. During WPHT, all patients were treated with cisplatin, 40 mg/m 2 intravenously weekly. Toxicity of treatment was scored according to the Common Terminology Criteria for Adverse Events v3.0 (CTCAE v3.0). The mean survival was 25 months (range, 3 to 27 months). The actuarial overall survival, disease-free survival, locoregional control and distant metastasis-free rates at 2 years were 67%, 77%, 90% and 88%, respectively. The average of uniformity index and conformal index was 1.06 and 1.19, respectively. One grade 3 of acute toxicity for diarrhea, thrombocytopenia and three grade 3 leucopenia were noted during CCRT. Only one grade 3 of subacute toxicity for thrombocytopenia was noted. There were no grade 3 or 4 subacute toxicities of anemia, leucopenia, genitourinary or gastrointestinal effects. Compared with conventional whole pelvic radiation therapy (WPRT), WPHT decreases the mean dose to rectum, bladder and intestines successfully. HT provides feasible clinical outcomes in locally advanced cervical cancer patients. Long-term follow-up and enroll more locally advanced cervical carcinoma patients by limiting bone marrow radiation dose with WPHT technique is warranted

  10. Dosimetric comparison between helical tomotherapy and volumetric modulated arc-therapy for non-anaplastic thyroid cancer treatment.

    Science.gov (United States)

    Khalifa, Jonathan; Vieillevigne, Laure; Boyrie, Sabrina; Ouali, Monia; Filleron, Thomas; Rives, Michel; Laprie, Anne

    2014-11-26

    To evaluate and compare dosimetric parameters of volumetric modulated arctherapy (VMAT) and helical tomotherapy (HT) for non-anaplastic thyroid cancer adjuvant radiotherapy. Twelve patients with non-anaplastic thyroid cancer at high risk of local relapse received adjuvant external beam radiotherapy with curative intent in our institution, using a two-dose level prescription with a simultaneous integrated boost approach. Each patient was re-planned by the same physicist twice using both VMAT and HT. Several dosimetric quality indexes were used: target coverage index (proportion of the target volume covered by the reference isodose), healthy tissue conformity index (proportion of the reference isodose volume including the target volume), conformation number (combining both previous indexes), Dice Similarity Coefficient (DSC), and homogeneity index ((D2%-D98%)/prescribed dose). Dose-volume histogram statistics were also compared. HT provided statistically better target coverage index and homogeneity index for low risk PTV in comparison with VMAT (respectively 0.99 vs. 0.97 (p=0.008) and 0.22 vs. 0.25 (p=0.016)). However, HT provided poorer results for healthy tissue conformity index, conformation number and DSC with low risk and high risk PTV. As regards organs at risk sparing, by comparison with VMAT, HT statistically decreased the D2% to medullary canal (25.3 Gy vs. 32.6 Gy (p=0.003)). Besides, HT allowed a slight sparing dose for the controlateral parotid (Dmean: 4.3 Gy vs. 6.6 Gy (p=0.032)) and for the controlateral sub-maxillary gland (Dmean: 29.1 Gy vs. 33.1 Gy (p=0.041)). Both VMAT and HT techniques for adjuvant treatment of non-anaplastic thyroid cancer provide globally attractive treatment plans with slight dosimetric differences. However, helical tomotherapy clearly provides a benefit in term of medullary canal sparing.

  11. Independent quality assurance of a helical tomotherapy machine using the dose magnifying glass

    International Nuclear Information System (INIS)

    Wong, J.H.D.; Rosenfeld, A.B.; Hardcastle, N.; Bayliss, A.; Tolakanahalli, R.; Tome, W.

    2010-01-01

    Full text: Helical tomotherapy presents a new paradigm in cancer treatment integrating image guidance and intensity modulated radiation therapy in one system. Many of the tomotherapy QAs involve using the MYCT detector to QA the unit itself. Although convenient, they lack independence from the system under measurement. This work describes the use of a novel silicon detector as an independent tool for tomotherapy QA. The dose magnifying glass (DMG) is a 128 channel array of Si strip detectors. It was used to measure three tomotherapy QA parameters, (a) MLC alignment, (b) leaf latency and (c) leaf output factor (LOF). MLC alignment test measures the alignment of the MLC bank and the gantry center of rotation. Leaf latency is defined as the time taken for the leaf to travel from a closed state to an open state (and vice versa). Measurement are acquired at a 3 ms sampling rate with the detector pitch of 0.2 mm. Leaf latency for 50-400 ms projection time were measured. LOF measures the effect of the state of the adjacent leaves on a selected leaf of interest. For the tomotherapy unit tested, the DMG measured a 1.3 mm misalignment in the MLC alignment test. The leaf latency (Fig. I) shows a large non linearity in projection times <200 ms. The DMG measured a LOF of up to 25.3% when both adjacent leaves were opened. DMG with its high spatial and temporal resolutions presents a unique and independent tool for measuring selected tomotherapy QA parameters. (author)

  12. Performance characterization of megavoltage computed tomography imaging on a helical tomotherapy unit

    International Nuclear Information System (INIS)

    Meeks, Sanford L.; Harmon, Joseph F. Jr.; Langen, Katja M.; Willoughby, Twyla R.; Wagner, Thomas H.; Kupelian, Patrick A.

    2005-01-01

    Helical tomotherapy is an innovative means of delivering IGRT and IMRT using a device that combines features of a linear accelerator and a helical computed tomography (CT) scanner. The HI-ART II can generate CT images from the same megavoltage x-ray beam it uses for treatment. These megavoltage CT (MVCT) images offer verification of the patient position prior to and potentially during radiation therapy. Since the unit uses the actual treatment beam as the x-ray source for image acquisition, no surrogate telemetry systems are required to register image space to treatment space. The disadvantage to using the treatment beam for imaging, however, is that the physics of radiation interactions in the megavoltage energy range may force compromises between the dose delivered and the image quality in comparison to diagnostic CT scanners. The performance of the system is therefore characterized in terms of objective measures of noise, uniformity, contrast, and spatial resolution as a function of the dose delivered by the MVCT beam. The uniformity and spatial resolutions of MVCT images generated by the HI-ART II are comparable to that of diagnostic CT images. Furthermore, the MVCT scan contrast is linear with respect to the electron density of material imaged. MVCT images do not have the same performance characteristics as state-of-the art diagnostic CT scanners when one objectively examines noise and low-contrast resolution. These inferior results may be explained, at least partially, by the low doses delivered by our unit; the dose is 1.1 cGy in a 20 cm diameter cylindrical phantom. In spite of the poorer low-contrast resolution, these relatively low-dose MVCT scans provide sufficient contrast to delineate many soft-tissue structures. Hence, these images are useful not only for verifying the patient's position at the time of therapy, but they are also sufficient for delineating many anatomic structures. In conjunction with the ability to recalculate radiotherapy doses on

  13. SU-F-BRB-13: Correlation of Improved Target and Organ-At-Risk Dosimetric Quantities and Clinical Outcomes for Helical Tomotherapy Treated Mesothelioma

    Energy Technology Data Exchange (ETDEWEB)

    Qi, S; Kishan, A; Alexander, S; Lee, P; Selch, M; Kupelian, P; Steiberg, M; Low, D [UCLA, Los Angeles, CA (United States)

    2015-06-15

    Purpose: We have observed improved local control probability (LCP) for adjuvant mesothelioma radiotherapy following pleurectomy/decortication using Tomotherapy compared to the conventional 3D technique (p<0.05). This work assesses the correlation between the improved clinical outcomes against dosimetry quantities. Methods: Thirty-eight mesothelioma cases consecutively treated at our clinic were retrospectively analyzed. Sixteen patients were treated using 3D technique planned on the Eclipse for c-arm accelerators prior to 7/2012; the other 22 cases were treated on Tomotherapy using helical IMRT after 7/2012. Typical 3D plans consisting of 15 MV AP/PA photon fields prescribed to 10 cm depth followed by matching electron fields with energy ranging from 8–16 MeV. Tomotherapy plans were designed using 2.5cm jaw, 0.287 pitch with directional blocking of the contralateral lung. The same prescription of 45 Gy (1.8GyX25) was used for both techniques. The dosimetry metrics for the critical structures: ipsilateral-/contralateral-lung, heart, cord, esophagus, etc were compared between two techniques. Results: Superior LCP is closely associated with improved target coverage. Tomotherapy plans yielded dramatically better target coverage and less dose heterogeneity despite of more advanced/larger disease. The averaged PTV volumes were 2287.3±569.9 (Tomotherapy) vs. 1904.8±312.3cc (3D); V100s were: 91.1±4.0 (%) vs. 47.8±12.7 (%) with heterogeneity indices of 1.20±0.1 vs.1.37±0.38 and for the Tomotherapy and 3D plans, respectively. Compared to the 3D technique, we observed significant lower maximum cord doses (p<0.001), lower mean esophagus doses (p<0.002), and lower heart mean doses when tumor was left-sided (p=0.002). For ipsilateral-/contralateral-lungs, however, the mean doses and V20, V5 of Tomotherapy plans were significantly higher than the 3D plans (p<0.01) regardless which sides of lung were treated. However, rates of radiation pneumonitis were no different

  14. Feasibility study of helical tomotherapy for total body or total marrow irradiation

    International Nuclear Information System (INIS)

    Hui, Susanta K.; Kapatoes, Jeff; Fowler, Jack; Henderson, Douglas; Olivera, Gustavo; Manon, Rafael R.; Gerbi, Bruce; Mackie, T. R.; Welsh, James S.

    2005-01-01

    Total body radiation (TBI) has been used for many years as a preconditioning agent before bone marrow transplantation. Many side effects still plague its use. We investigated the planning and delivery of total body irradiation (TBI) and selective total marrow irradiation (TMI) and a reduced radiation dose to sensitive structures using image-guided helical tomotherapy. To assess the feasibility of using helical tomotherapy (A) we studied variations in pitch, field width, and modulation factor on total body and total marrow helical tomotherapy treatments. We varied these parameters to provide a uniform dose along with a treatment times similar to conventional TBI (15-30 min). (B) We also investigated limited (head, chest, and pelvis) megavoltage CT (MVCT) scanning for the dimensional pretreatment setup verification rather than total body MVCT scanning to shorten the overall treatment time per treatment fraction. (C) We placed thermoluminescent detectors (TLDs) inside a Rando phantom to measure the dose at seven anatomical sites, including the lungs. A simulated TBI treatment showed homogeneous dose coverage (±10%) to the whole body. Doses to the sensitive organs were reduced by 35%-70% of the target dose. TLD measurements on Rando showed an accurate dose delivery (±7%) to the target and critical organs. In the TMI study, the dose was delivered conformally to the bone marrow only. The TBI and TMI treatment delivery time was reduced (by 50%) by increasing the field width from 2.5 to 5.0 cm in the inferior-superior direction. A limited MVCT reduced the target localization time 60% compared to whole body MVCT. MVCT image-guided helical tomotherapy offers a novel method to deliver a precise, homogeneous radiation dose to the whole body target while reducing the dose significantly to all critical organs. A judicious selection of pitch, modulation factor, and field size is required to produce a homogeneous dose distribution along with an acceptable treatment time. In

  15. Evaluation of image-guided helical tomotherapy for the retreatment of spinal metastasis

    International Nuclear Information System (INIS)

    Mahan, Stephen L.; Ramsey, Chester R.; Scaperoth, Daniel D.; Chase, Daniel J.; Byrne, Thomas E.

    2005-01-01

    Introduction: Patients with vertebral metastasis that receive radiation therapy are typically treated to the spinal cord tolerance dose. As such, it is difficult to successfully deliver a second course of radiation therapy for patients with overlapping treatment volumes. In this study, an image-guided helical tomotherapy system was evaluated for the retreatment of previously irradiated vertebral metastasis. Methods and Materials: Helical tomotherapy dose gradients and maximum cord doses were measured in a cylindrical phantom for geometric test cases with separations between the planning target volume (PTV) and the spinal cord organ at risk (OAR) of 2 mm, 4 mm, 6 mm, 8 mm, and 10 mm. Megavoltage computed tomography (CT) images were examined for their ability to localize spinal anatomy for positioning purposes by repeat imaging of the cervical spine in an anthropomorphic phantom. In addition to the phantom studies, 8 patients with cord compressions that had received previous radiation therapy were retreated to a mean dose of 28 Gy using conventional fractionation. Results and Discussion: Megavoltage CT images were capable of positioning an anthropomorphic phantom to within ±1.2 mm (2σ) superior-inferiorly and within ±0.6 mm (2σ) anterior-posteriorly and laterally. Dose gradients of 10% per mm were measured in phantom while PTV uniformity indices of less than 11% were maintained. The calculated maximum cord dose was 25% of the prescribed dose for a 10-mm PTV-to-OAR separation and 71% of the prescribed dose for a PTV-to-OAR separation of 2 mm. Eight patients total have been treated without radiation-induced myelopathy or any other adverse effects from treatment. Conclusions: A technique has been evaluated for the retreatment of vertebral metastasis using image-guided helical tomotherapy. Phantom and patient studies indicated that a tomotherapy system is capable of delivering dose gradients of 10% per mm and positioning the patient within 1.2 mm without the use of

  16. The role of helical tomotherapy in the treatment of bone plasmacytoma.

    Science.gov (United States)

    Chargari, Cyrus; Hijal, Tarek; Bouscary, Didier; Caussa, Lucas; Dendale, Remi; Zefkili, Sofia; Fourquet, Alain; Kirova, Youlia M

    2012-01-01

    We evaluated the early clinical outcome of patients with solitary bone plasmacytoma (SP) or a solitary lesion of multiple myeloma (MM) treated with helical tomotherapy (HT) compared with 3D conformal radiotherapy (3D-CRT), in terms of target coverage and exposure of critical organs. Ten patients with SP and 3 patients with a solitary lesion of MM underwent radiation therapy (RT) delivered by HT, to a dose of 40 Gy in 20 fractions. Treatment planning was then performed with 3D-CRT and the dosimetric parameters of both techniques were compared. Patients were also assessed for response to treatment and acute toxicities. With a median follow-up of 13 months, 78% of patients with pain before RT had resolution of their symptoms. Coverage of target lesion was adequate with both techniques in 12 of 13 patients. Target coverage was significantly lower for HT (V(95%) = 98.55% vs. 97.15%; p = 0.04, for 3D-CRT and HT, respectively). Target overdoses were also lower with HT (V(105%) = 2.01% vs. 0.19%; p= 0.16), although nonsignificant. Finally, there were no significant differences in organs-at-risk irradiation between both techniques. The early treatment tolerance was excellent, with no toxicity higher than grade I. RT of SP and MM with a solitary lesion can be safely delivered with HT, with no major acute side effects and good symptomatic control. Finally, HT provides a dosimetry similar to that of 3D-CRT in terms of organs-at-risk sparing and target volume coverage. Copyright © 2012 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.

  17. The role of helical tomotherapy in the treatment of bone plasmacytoma

    International Nuclear Information System (INIS)

    Chargari, Cyrus; Hijal, Tarek; Bouscary, Didier; Caussa, Lucas; Dendale, Remi; Zefkili, Sofia; Fourquet, Alain; Kirova, Youlia M.

    2012-01-01

    We evaluated the early clinical outcome of patients with solitary bone plasmacytoma (SP) or a solitary lesion of multiple myeloma (MM) treated with helical tomotherapy (HT) compared with 3D conformal radiotherapy (3D-CRT), in terms of target coverage and exposure of critical organs. Ten patients with SP and 3 patients with a solitary lesion of MM underwent radiation therapy (RT) delivered by HT, to a dose of 40 Gy in 20 fractions. Treatment planning was then performed with 3D-CRT and the dosimetric parameters of both techniques were compared. Patients were also assessed for response to treatment and acute toxicities. With a median follow-up of 13 months, 78% of patients with pain before RT had resolution of their symptoms. Coverage of target lesion was adequate with both techniques in 12 of 13 patients. Target coverage was significantly lower for HT (V 95% = 98.55% vs. 97.15%; p = 0.04, for 3D-CRT and HT, respectively). Target overdoses were also lower with HT (V 105% = 2.01% vs. 0.19%; p= 0.16), although nonsignificant. Finally, there were no significant differences in organs-at-risk irradiation between both techniques. The early treatment tolerance was excellent, with no toxicity higher than grade I. RT of SP and MM with a solitary lesion can be safely delivered with HT, with no major acute side effects and good symptomatic control. Finally, HT provides a dosimetry similar to that of 3D-CRT in terms of organs-at-risk sparing and target volume coverage.

  18. The role of helical tomotherapy in the treatment of bone plasmacytoma

    Energy Technology Data Exchange (ETDEWEB)

    Chargari, Cyrus; Hijal, Tarek [Department of Radiation Oncology, Institut Curie, Paris (France); Bouscary, Didier [Department of Hematology, Hopital Cochin, Paris (France); Caussa, Lucas; Dendale, Remi; Zefkili, Sofia; Fourquet, Alain [Department of Radiation Oncology, Institut Curie, Paris (France); Kirova, Youlia M., E-mail: youlia.kirova@curie.net [Department of Radiation Oncology, Institut Curie, Paris (France)

    2012-04-01

    We evaluated the early clinical outcome of patients with solitary bone plasmacytoma (SP) or a solitary lesion of multiple myeloma (MM) treated with helical tomotherapy (HT) compared with 3D conformal radiotherapy (3D-CRT), in terms of target coverage and exposure of critical organs. Ten patients with SP and 3 patients with a solitary lesion of MM underwent radiation therapy (RT) delivered by HT, to a dose of 40 Gy in 20 fractions. Treatment planning was then performed with 3D-CRT and the dosimetric parameters of both techniques were compared. Patients were also assessed for response to treatment and acute toxicities. With a median follow-up of 13 months, 78% of patients with pain before RT had resolution of their symptoms. Coverage of target lesion was adequate with both techniques in 12 of 13 patients. Target coverage was significantly lower for HT (V{sub 95%} = 98.55% vs. 97.15%; p = 0.04, for 3D-CRT and HT, respectively). Target overdoses were also lower with HT (V{sub 105%} = 2.01% vs. 0.19%; p= 0.16), although nonsignificant. Finally, there were no significant differences in organs-at-risk irradiation between both techniques. The early treatment tolerance was excellent, with no toxicity higher than grade I. RT of SP and MM with a solitary lesion can be safely delivered with HT, with no major acute side effects and good symptomatic control. Finally, HT provides a dosimetry similar to that of 3D-CRT in terms of organs-at-risk sparing and target volume coverage.

  19. SU-E-T-371: Validation of Organ Doses Delivered During Craniospinal Irradiation with Helical Tomotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Andujar, A; Chen, J; Garcia, A; Haas-Kogan, D [University of San Francisco, San Francisco, CA (United States)

    2014-06-01

    Purpose: New techniques have been developed to deliver more conformal treatments to the craniospinal axis. One concern, however, is the widespread low dose delivered and implications for possible late effects. The purpose of this work is for the first time to validate the organ doses calculated by the treatment planning system (TPS), including out-of-field doses for a pediatric craniospinal treatment (CSI). Methods: A CSI plan prescribed to 23.4 Gy and a posterior fossa boost plan to 30.6 Gy (total dose 54.0 Gy) was developed for a pediatric anthropomorphic phantom representing a 13 yearold- child. For the CSI plan, the planning target volumes (PTV) consisted of the brain and spinal cord with 2 mm and 5 mm expansions, respectively. Organs at risk (OAR) were contoured and included in the plan optimization. The plans were delivered on a helical tomotherapy unit. Thermoluminescent dosimeters (TLDs) were used to measure the dose at 54 positions within the PTV and OARs. Results: For the CSI treatment, the mean percent difference between TPS dose calculations and measurements was 5% for the PTV and 10% for the OARs. For the boost, the average was 3% for the PTV. The percent difference for the OARs, which lie outside the field and received a small fraction of the prescription dose, varied from 15% to 200%. However in terms of absolute dose, the average difference between measurement and TPS per treatment Gy was 2 cGy/Gy and 3 mGy/Gy for the CSI and boost plans, respectively. Conclusion: There was good agreement between doses calculated by the TPS and measurements for the CSI treatment. Higher percent differences were observed for out-of-field doses in the boost plan, but absolute dose differences were very small compared to the prescription dose. These findings can help in the estimation of late effects after radiotherapy for pediatric patients.

  20. Dose-volume and biological-model based comparison between helical tomotherapy and (inverse-planned) IMAT for prostate tumours

    International Nuclear Information System (INIS)

    Iori, Mauro; Cattaneo, Giovanni Mauro; Cagni, Elisabetta; Fiorino, Claudio; Borasi, Gianni; Riccardo, Calandrino; Iotti, Cinzia; Fazio, Ferruccio; Nahum, Alan E.

    2008-01-01

    Background and purpose: Helical tomotherapy (HT) and intensity-modulated arc therapy (IMAT) are two arc-based approaches to the delivery of intensity-modulated radiotherapy (IMRT). Through plan comparisons we have investigated the potential of IMAT, both with constant (conventional or IMAT-C) and variable (non-conventional or IMAT-NC, a theoretical exercise) dose-rate, to serve as an alternative to helical tomotherapy. Materials and methods: Six patients with prostate tumours treated by HT with a moderately hypo-fractionated protocol, involving a simultaneous integrated boost, were re-planned as IMAT treatments. A method for IMAT inverse-planning using a commercial module for static IMRT combined with a multi-leaf collimator (MLC) arc-sequencing was developed. IMAT plans were compared to HT plans in terms of dose statistics and radiobiological indices. Results: Concerning the planning target volume (PTV), the mean doses for all PTVs were similar for HT and IMAT-C plans with minimum dose, target coverage, equivalent uniform dose (EUD) and tumour control probability (TCP) values being generally higher for HT; maximum dose and degree of heterogeneity were instead higher for IMAT-C. In relation to organs at risk, mean doses and normal tissue complication probability (NTCP) values were similar between the two modalities, except for the penile bulb where IMAT was significantly better. Re-normalizing all plans to the same rectal toxicity (NTCP = 5%), the HT modality yielded higher TCP than IMAT-C but there was no significant difference between HT and IMAT-NC. The integral dose with HT was higher than that for IMAT. Conclusions: with regards to the plan analysis, the HT is superior to IMAT-C in terms of target coverage and dose homogeneity within the PTV. Introducing dose-rate variation during arc-rotation, not deliverable with current linac technology, the simulations result in comparable plan indices between (IMAT-NC) and HT

  1. Feasibility of tomotherapy for Graves' ophthalmopathy. Dosimetry comparison with conventional radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Nam P.; Krafft, Shane P. [Arizona Univ., Tucson, AZ (United States). Dept. of Radiation Oncology; Vos, Paul [East Carolina Univ., Greenville, NC (US). Dept. of Biostatistics] (and others)

    2011-09-15

    To compare the dosimetry of tomotherapy and the conventional half-beam technique (HBT) or non-split beam technique (NSBT) for target coverage and radiation dose to the lacrimal glands and lens. A retrospective review of 7 patients with Graves' ophthalmopathy who had radiotherapy because of disease progression on high steroid dose is reported: 3 patients were treated with tomotherapy and 4 patients with HBT. Compared to HBT, tomotherapy may provide better target coverage and significant reduction of radiation dose to the lacrimal glands and a higher dose to the lens. The NSBT improved target coverage but resulted in significantly higher doses to the lens and lacrimal glands. Tomotherapy may provide better coverage of the target volume and may be more effective in reducing severe exophthalmos compared to the conventional radiotherapy technique. (orig.)

  2. Dosimetric comparison between conformational irradiation and helical tomo-therapy in supra-diaphragmatic Hodgkin disease in paediatrics; Comparaison dosimetrique entre l'irradiation conformationelle et la tomotherapie helicoidale dans la maladie de Hodgkin sus-diaphragmatique en pediatrie

    Energy Technology Data Exchange (ETDEWEB)

    Padovani, L.; Taright, N.; Muraracciole, X.; Nomikossof, N.; Capdeville, S.; Portal, T.; Cowen, D. [Assistance publique-hopitaux de Marseille (France)

    2011-10-15

    The authors report the comparison of dosimetry when using three-dimensional conformational radiotherapy or intensity-modulated conformational radiotherapy (IMRT) in the case of 13 children treated for a Hodgkin disease. The comparison is made in terms of previsional target volume (PTV) coverage and of doses received at the level of organs at risk. Coverage is almost the same for both techniques. Helical tomo-therapy allows the reduction of doses delivered to the heart, spine and lungs, including low doses (V5 and V10) while respecting an identical PTV coverage. This dose reduction could result in a reduction of toxicity on the long term, which is a major challenge for cured children. Short communication

  3. Effects of megavoltage computed tomographic scan methodology on setup verification and adaptive dose calculation in helical TomoTherapy.

    Science.gov (United States)

    Zhu, Jian; Bai, Tong; Gu, Jiabing; Sun, Ziwen; Wei, Yumei; Li, Baosheng; Yin, Yong

    2018-04-27

    To evaluate the effect of pretreatment megavoltage computed tomographic (MVCT) scan methodology on setup verification and adaptive dose calculation in helical TomoTherapy. Both anthropomorphic heterogeneous chest and pelvic phantoms were planned with virtual targets by TomoTherapy Physicist Station and were scanned with TomoTherapy megavoltage image-guided radiotherapy (IGRT) system consisted of six groups of options: three different acquisition pitches (APs) of 'fine', 'normal' and 'coarse' were implemented by multiplying 2 different corresponding reconstruction intervals (RIs). In order to mimic patient setup variations, each phantom was shifted 5 mm away manually in three orthogonal directions respectively. The effect of MVCT scan options was analyzed in image quality (CT number and noise), adaptive dose calculation deviations and positional correction variations. MVCT scanning time with pitch of 'fine' was approximately twice of 'normal' and 3 times more than 'coarse' setting, all which will not be affected by different RIs. MVCT with different APs delivered almost identical CT numbers and image noise inside 7 selected regions with various densities. DVH curves from adaptive dose calculation with serial MVCT images acquired by varied pitches overlapped together, where as there are no significant difference in all p values of intercept & slope of emulational spinal cord (p = 0.761 & 0.277), heart (p = 0.984 & 0.978), lungs (p = 0.992 & 0.980), soft tissue (p = 0.319 & 0.951) and bony structures (p = 0.960 & 0.929) between the most elaborated and the roughest serials of MVCT. Furthermore, gamma index analysis shown that, compared to the dose distribution calculated on MVCT of 'fine', only 0.2% or 1.1% of the points analyzed on MVCT of 'normal' or 'coarse' do not meet the defined gamma criterion. On chest phantom, all registration errors larger than 1 mm appeared at superior-inferior axis, which cannot be avoided with the smallest AP and RI

  4. Usefulness of Non-coplanar Helical Tomotherapy Using Variable Axis Baseplate

    International Nuclear Information System (INIS)

    Ha, Jin Sook; Chung, Yoon Sun; Lee, Ik Jae; Shin, Dong Bong; Kim, Jong Dae; Kim, Sei Joon; Jeon, Mi Jin; Chok, Yoon Jin; Kim, Ki Kwang; Lee, Seul Bee

    2011-01-01

    Helical Tomotherapy allows only coplanar beam delivery because it does not allow couch rotation. We investigated a method to introduce non-coplanar beam by tilting a patient's head for Tomotherapy. The aim of this study was to compare intrafractional movement during Tomotherapy between coplanar and non-coplanar patient's setup. Helical Tomotherapy was used for treating eight patients with intracranial tumor. The subjects were divided into three groups: one group (coplanar) of 2 patients who lay on S-plate with supine position and wore thermoplastic mask for immobilizing the head, second group (non-coplanar) of 3 patients who lay on S-plate with supine position and whose head was tilted with Variable Axis Baseplate and wore thermoplastic mask, and third group (non-coplanar plus mouthpiece) of 3 patients whose head was tilted and wore a mouthpiece immobilization device and thermoplastic mask. The patients were treated with Tomotherapy after treatment planning with Tomotherapy Planning System. Megavoltage computed tomography (MVCT) was performed before and after treatment, and the intrafractional error was measured with lateral(X), longitudinal(Y), vertical(Z) direction movements and vector (√x 2 +√y 2 +√z 2 ) value for assessing overall movement. Intrafractional error was compared among three groups by taking the error of MVCT taken after the treatment. As the correction values (X, Y, Z) between MVCT image taken after treatment and CT-simulation image are close to zero, the patient movement is small. When the mean values of movement of each direction for non-coplanar setup were compared with coplanar setup group, X-axis movement was decreased by 13%, but Y-axis and Z-axis movement were increased by 109% and 88%, respectively. Movements of Y-axis and Z-axis with non-coplanar setup were relatively greater than that of X-axis since a tilted head tended to slip down. The mean of X-axis movement of the group who used a mouthpiece was greater by 9.4% than the group

  5. Prostate contouring uncertainty in megavoltage computed tomography images acquired with a helical tomotherapy unit during image-guided radiation therapy

    International Nuclear Information System (INIS)

    Song, William Y.; Chiu, Bernard; Bauman, Glenn S.; Lock, Michael; Rodrigues, George; Ash, Robert; Lewis, Craig; Fenster, Aaron; Battista, Jerry J.; Van Dyk, Jake

    2006-01-01

    Purpose: To evaluate the image-guidance capabilities of megavoltage computed tomography (MVCT), this article compares the interobserver and intraobserver contouring uncertainty in kilovoltage computed tomography (KVCT) used for radiotherapy planning with MVCT acquired with helical tomotherapy. Methods and Materials: Five prostate-cancer patients were evaluated. Each patient underwent a KVCT and an MVCT study, a total of 10 CT studies. For interobserver variability analysis, four radiation oncologists, one physicist, and two radiation therapists (seven observers in total) contoured the prostate and seminal vesicles (SV) in the 10 studies. The intraobserver variability was assessed by asking all observers to repeat the contouring of 1 patient's KVCT and MVCT studies. Quantitative analysis of contour variations was performed by use of volumes and radial distances. Results: The interobserver and intraobserver contouring uncertainty was larger in MVCT compared with KVCT. Observers consistently segmented larger volumes on MVCT where the ratio of average prostate and SV volumes was 1.1 and 1.2, respectively. On average (interobserver and intraobserver), the local delineation variability, in terms of standard deviations [Δσ = √(σ 2 MVCT - σ 2 KVCT )], increased by 0.32 cm from KVCT to MVCT. Conclusions: Although MVCT was inferior to KVCT for prostate delineation, the application of MVCT in prostate radiotherapy remains useful

  6. Fast Helical Tomotherapy in a head and neck cancer planning study: is time priceless?

    International Nuclear Information System (INIS)

    Van Gestel, Dirk; De Kerf, Geert; Wouters, Kristien; Crijns, Wouter; Vermorken, Jan B.; Gregoire, Vincent; Verellen, Dirk

    2015-01-01

    The last few years, in radiotherapy there has been a growing focus on speed of treatment delivery (largely driven by economical and commercial interests). This study investigates the influence of treatment time on plan quality for helical tomotherapy (HT), using delivery times with Volumetric Modulated Arc Therapy (VMAT; Rapid Arc [RA]) as reference. In a previous study, double arc RA (Eclipse) and standard HT plans (TomoHD™) were created for five oropharyngeal cancer patients and reported according to ICRU 83 guidelines. By modifying the beam width from 2.5 to 5.0 cm, elevating the pitch and lowering the modulation factor, “TomoFast” (TF) plans were generated with treatment times equal to RA plans. To quantify the impact of TF’s craniocaudal gradient, similar plans were generated on TomoEdge TM (TomoEdgeFast;TEF). The homogeneity index (HI), conformity index (CI), mean dose, D near-max (D2) and D near-min (D98) of the PTVs were analyzed as well as the mean dose, specific critical doses and volumes of 26 organs at risk (OARs). Data were analyzed using repeated measures ANOVA. With a mean treatment time of 3.05 min (RA), 2.89 min (TF) and 2.95 min (TEF), PTV therapeutic coverage was more homogeneous with TF (HI.07;SE.01) and TEF (HI.08;SE.01) compared to RA (HI.10;SE.01), while PTV prophylactic was most homogeneous with RA. Mean doses to parotid glands were comparable for RA, TF, TEF: 25.62, 25.34, 23.09 Gy for contralateral and 32.02, 31.96, 30.01 Gy for ipsilateral glands, respectively. OARs’ mean doses varied between different approaches not favoring a particular technique. TF’s higher dose to OARs at the cranial-caudal edges of the PTVs and its higher integral dose, both due to the extended cranial-caudal gradient, seems to be solved by the new TomoEdge™ software. However, all these faster techniques lose part of standard TomoHD’s OAR sparing capacity It is possible to treat oropharyngeal cancer patients using HT (TF/TEF) within time

  7. Clinical Study of Nasopharyngeal Carcinoma Treated by Helical Tomotherapy in China: 5-Year Outcomes

    Directory of Open Access Journals (Sweden)

    Lei Du

    2014-01-01

    Full Text Available Background. To evaluate the outcomes of nasopharyngeal carcinoma (NPC patients treated with helical tomotherapy (HT. Methods. Between September 2007 and August 2012, 190 newly diagnosed NPC patients were treated with HT. Thirty-one patients were treated with radiation therapy as single modality, 129 with additional cisplatin-based chemotherapy with or without anti-EGFR monoclonal antibody therapy, and 30 with concurrent anti-EGFR monoclonal antibody therapy. Results. Acute radiation related side effects were mainly grade 1 or 2. Grade 3 and greater toxicities were rarely noted. The median followup was 32 (3–38 months. The local relapse-free survival (LRFS, nodal relapse-free survival (NRFS, distant metastasis-free survival (DMFS, and overall survival (OS were 96.1%, 98.2%, 92.0%, and 86.3%, respectively, at 3 years. Cox multivariate regression analysis showed that age and T stage were independent predictors for 3-year OS. Conclusions. Helical tomotherapy for NPC patients achieved excellent 3-year locoregional control, distant metastasis-free survival, and overall survival, with relatively minor acute and late toxicities. Age and T stage were the main prognosis factors.

  8. Independent calculation of dose distributions for helical tomotherapy using a conventional treatment planning system

    Energy Technology Data Exchange (ETDEWEB)

    Klüter, Sebastian, E-mail: sebastian.klueter@med.uni-heidelberg.de; Schubert, Kai; Lissner, Steffen; Sterzing, Florian; Oetzel, Dieter; Debus, Jürgen [Department of Radiation Oncology, Heidelberg University Hospital, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany, and Heidelberg Institute for Radiation Oncology (HIRO), Im Neuenheimer Feld 400, 69120 Heidelberg, Germany, and German Consortium for Translational Cancer Research (DKTK), Im Neuenheimer Feld 400, 69120 Heidelberg (Germany); Schlegel, Wolfgang [German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Oelfke, Uwe [German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany and Joint Department of Physics at The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London SM2 5NG (United Kingdom); Nill, Simeon [Joint Department of Physics at The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London SM2 5NG (United Kingdom)

    2014-08-15

    Purpose: The dosimetric verification of treatment plans in helical tomotherapy usually is carried out via verification measurements. In this study, a method for independent dose calculation of tomotherapy treatment plans is presented, that uses a conventional treatment planning system with a pencil kernel dose calculation algorithm for generation of verification dose distributions based on patient CT data. Methods: A pencil beam algorithm that directly uses measured beam data was configured for dose calculation for a tomotherapy machine. Tomotherapy treatment plans were converted into a format readable by an in-house treatment planning system by assigning each projection to one static treatment field and shifting the calculation isocenter for each field in order to account for the couch movement. The modulation of the fluence for each projection is read out of the delivery sinogram, and with the kernel-based dose calculation, this information can directly be used for dose calculation without the need for decomposition of the sinogram. The sinogram values are only corrected for leaf output and leaf latency. Using the converted treatment plans, dose was recalculated with the independent treatment planning system. Multiple treatment plans ranging from simple static fields to real patient treatment plans were calculated using the new approach and either compared to actual measurements or the 3D dose distribution calculated by the tomotherapy treatment planning system. In addition, dose–volume histograms were calculated for the patient plans. Results: Except for minor deviations at the maximum field size, the pencil beam dose calculation for static beams agreed with measurements in a water tank within 2%/2 mm. A mean deviation to point dose measurements in the cheese phantom of 0.89% ± 0.81% was found for unmodulated helical plans. A mean voxel-based deviation of −0.67% ± 1.11% for all voxels in the respective high dose region (dose values >80%), and a mean local

  9. Independent calculation of dose distributions for helical tomotherapy using a conventional treatment planning system

    International Nuclear Information System (INIS)

    Klüter, Sebastian; Schubert, Kai; Lissner, Steffen; Sterzing, Florian; Oetzel, Dieter; Debus, Jürgen; Schlegel, Wolfgang; Oelfke, Uwe; Nill, Simeon

    2014-01-01

    Purpose: The dosimetric verification of treatment plans in helical tomotherapy usually is carried out via verification measurements. In this study, a method for independent dose calculation of tomotherapy treatment plans is presented, that uses a conventional treatment planning system with a pencil kernel dose calculation algorithm for generation of verification dose distributions based on patient CT data. Methods: A pencil beam algorithm that directly uses measured beam data was configured for dose calculation for a tomotherapy machine. Tomotherapy treatment plans were converted into a format readable by an in-house treatment planning system by assigning each projection to one static treatment field and shifting the calculation isocenter for each field in order to account for the couch movement. The modulation of the fluence for each projection is read out of the delivery sinogram, and with the kernel-based dose calculation, this information can directly be used for dose calculation without the need for decomposition of the sinogram. The sinogram values are only corrected for leaf output and leaf latency. Using the converted treatment plans, dose was recalculated with the independent treatment planning system. Multiple treatment plans ranging from simple static fields to real patient treatment plans were calculated using the new approach and either compared to actual measurements or the 3D dose distribution calculated by the tomotherapy treatment planning system. In addition, dose–volume histograms were calculated for the patient plans. Results: Except for minor deviations at the maximum field size, the pencil beam dose calculation for static beams agreed with measurements in a water tank within 2%/2 mm. A mean deviation to point dose measurements in the cheese phantom of 0.89% ± 0.81% was found for unmodulated helical plans. A mean voxel-based deviation of −0.67% ± 1.11% for all voxels in the respective high dose region (dose values >80%), and a mean local

  10. Investigation of Accelerated Partial Breast Patient Alignment and Treatment With Helical Tomotherapy Unit

    International Nuclear Information System (INIS)

    Langen, Katja M.; Buchholz, Daniel J.; Burch, Doug R. C.; Burkavage, Rob C.; Limaye, Arti U.; Meeks, Sanford L.; Kupelian, Patrick A.; Ruchala, Kenneth J.; Haimerl, Jason; Henderson, Doug; Olivera, Gustavo H.

    2008-01-01

    Purpose: To determine the precision of megavoltage computed tomography (MVCT)-based alignment of the seroma cavity for patients undergoing partial breast irradiation; and to determine whether accelerated partial breast irradiation (APBI) plans can be generated for TomoTherapy deliveries that meet the National Surgical Adjuvant Breast and Bowel Project (NSABP) B-39/Radiation Therapy Oncology Group (RTOG) 0413 protocol guidelines for target coverage and normal tissue dose limitations. Methods and Materials: We obtained 50 MVCT images from 10 patients. An interuser study was designed to assess the alignment precision. Using a standard helical and a fixed beam prototype ('topotherapy') optimizer, two APBI plans for each patient were developed. Results: The precision of the MVCT-based seroma cavity alignment was better than 2 mm if averaged over the patient population. Both treatment techniques could be used to generate acceptable APBI plans for patients that fulfilled the recommended NSABP B-39/RTOG-0413 selection criteria. For plans of comparable treatment time, the conformation of the prescription dose to the target was greater for helical deliveries, while the ipsilateral lung dose was significantly reduced for the topotherapy plans. Conclusions: The inherent volumetric imaging capabilities of a TomoTherapy Hi-Art unit allow for alignment of patients undergoing partial breast irradiation that is determined from the visibility of the seroma cavity on the MVCT image. The precision of the MVCT-based alignment was better than 2 mm (± standard deviation) when averaged over the patient population. Using the NSABP B-39/RTOG-0413 guidelines, acceptable APBI treatment plans can be generated using helical- or topotherapy-based delivery techniques

  11. Helical tomotherapy for extramedullary hematopoiesis involving the pericardium in a patient with chronic myeloid leukemia.

    Science.gov (United States)

    Toms, Daniel R; Cannick, Leander; Stuart, Robert K; Jenrette, Joseph M; Terwiliger, Lacy

    2010-07-01

    Extramedullary hematopoiesis (EMH) refers to the development of foci of hematopoiesis outside its normal location in the bone marrow. This occurs normally during fetal development but is abnormal postpartum. The most common sites of EMH are the spleen and liver. The phenomenon occurs in a number of disease states, notably in myelofibrosis, thalassemia, immune thrombocytopenic purpura, sickle cell anemia, polycythemia vera, and myelodysplastic syndrome. Affected patients often develop symptoms related to the location of the EMH. Reported treatments include red blood cell transfusions, surgical excision, decompressive laminectomy in cases of cord compression, chemotherapy, and irradiation. Radiation therapy is highly effective for treating hematopoietic tissue because such tissues are extremely radiosensitive. Megavoltage helical tomotherapy is a technical advance in the delivery of radiation therapy, allowing more conformal and precise treatments. The present case report describes a patient with the diagnosis of atypical chronic myeloid leukemia and myelofibrosis who subsequently developed EMH of the pericardium with effusion and tamponade. By utilizing tomotherapy we were able to treat the pericardium while sparing much of the myocardium. The patient tolerated treatment well without acute adverse effects. His symptoms were alleviated, but he died approximately 1 year later.

  12. The use of a commercial QA device for daily output check of a helical tomotherapy unit

    International Nuclear Information System (INIS)

    Alaei, Parham; Hui, Susanta K.; Higgins, Patrick D.; Gerbi, Bruce J.

    2006-01-01

    Helical tomotherapy radiation therapy units, due to their particular design and differences from a traditional linear accelerator, require different procedures by which to perform routine quality assurance (QA). One of the principal QA tasks that should be performed daily on any radiation therapy equipment is the output constancy check. The daily output check on a Hi-Art TomoTherapy unit is commonly performed utilizing ionization chambers placed inside a solid water phantom. This provides a good check of output at one point, but does not give any information on either energy or symmetry of the beam, unless more than one point is measured. This also has the added disadvantage that it has to be done by the physics staff. To address these issues, and to simplify the process, such that it can be performed by radiation therapists, we investigated the use of a commercially available daily QA device to perform this task. The use of this device simplifies the task of daily output constancy checks and eliminates the need for continued physics involvement. This device can also be used to monitor the constancy of beam energy and cone profile and can potentially be used to detect gross errors in the couch movement or laser alignment

  13. A virtual source model for Monte Carlo simulation of helical tomotherapy.

    Science.gov (United States)

    Yuan, Jiankui; Rong, Yi; Chen, Quan

    2015-01-08

    The purpose of this study was to present a Monte Carlo (MC) simulation method based on a virtual source, jaw, and MLC model to calculate dose in patient for helical tomotherapy without the need of calculating phase-space files (PSFs). Current studies on the tomotherapy MC simulation adopt a full MC model, which includes extensive modeling of radiation source, primary and secondary jaws, and multileaf collimator (MLC). In the full MC model, PSFs need to be created at different scoring planes to facilitate the patient dose calculations. In the present work, the virtual source model (VSM) we established was based on the gold standard beam data of a tomotherapy unit, which can be exported from the treatment planning station (TPS). The TPS-generated sinograms were extracted from the archived patient XML (eXtensible Markup Language) files. The fluence map for the MC sampling was created by incorporating the percentage leaf open time (LOT) with leaf filter, jaw penumbra, and leaf latency contained from sinogram files. The VSM was validated for various geometry setups and clinical situations involving heterogeneous media and delivery quality assurance (DQA) cases. An agreement of < 1% was obtained between the measured and simulated results for percent depth doses (PDDs) and open beam profiles for all three jaw settings in the VSM commissioning. The accuracy of the VSM leaf filter model was verified in comparing the measured and simulated results for a Picket Fence pattern. An agreement of < 2% was achieved between the presented VSM and a published full MC model for heterogeneous phantoms. For complex clinical head and neck (HN) cases, the VSM-based MC simulation of DQA plans agreed with the film measurement with 98% of planar dose pixels passing on the 2%/2 mm gamma criteria. For patient treatment plans, results showed comparable dose-volume histograms (DVHs) for planning target volumes (PTVs) and organs at risk (OARs). Deviations observed in this study were consistent

  14. Conventional patient specific IMRT QA and 3DVH verification of dose distribution for helical tomotherapy

    International Nuclear Information System (INIS)

    Sharma, Prabhat Krishna; Joshi, Kishore; Epili, D.; Gavake, Umesh; Paul, Siji; Reena, Ph.; Jamema, S.V.

    2016-01-01

    In recent years, patient-specific IMRT QA has transitioned from point dose measurements by ion chambers to films to 2D array measurements. 3DVH software has taken this transition a step further by estimating the 3D dose delivered to the patient volume from 2D diode measurements using a planned dose perturbation (PDP) algorithm. This algorithm was developed to determine, if the conventional IMRT QA though sensitive at detecting errors, has any predictive power in detecting dose errors of clinical significance related to dose to the target volume and organs at risk (OAR). The aim of this study is to compare the conventional IMRT patient specific QA and 3DVH dose distribution for patients treated with helical tomotherapy (HT)

  15. Selection of the optimal radiotherapy technique for locally advanced hepatocellular carcinoma

    International Nuclear Information System (INIS)

    Lee, Ik-Jae; Seong, Jinsil; Koom, Woong-Sub; Kim, Yong-Bae; Jeon, Byeong-Chul; Kim, Joo-Ho; Han, Kwang-Hyub

    2011-01-01

    Various techniques are available for radiotherapy of hepatocellular carcinoma, including three-dimensional conformal radiotherapy, linac-based intensity-modulated radiotherapy and helical tomotherapy. The purpose of this study was to determine the optimal radiotherapy technique for hepatocellular carcinoma. Between 2006 and 2007, 12 patients underwent helical tomotherapy for locally advanced hepatocellular carcinoma. Helical tomotherapy computerized radiotherapy planning was compared with the best computerized radiotherapy planning for three-dimensional conformal radiotherapy and linac-based intensity-modulated radiotherapy for the delivery of 60 Gy in 30 fractions. Tumor coverage was assessed by conformity index, radical dose homogeneity index and moderated dose homogeneity index. Computerized radiotherapy planning was also compared according to the tumor location. Tumor coverage was shown to be significantly superior with helical tomotherapy as assessed by conformity index and moderated dose homogeneity index (P=0.002 and 0.03, respectively). Helical tomotherapy showed significantly lower irradiated liver volume at 40, 50 and 60 Gy (V40, V50 and V60, P=0.04, 0.03 and 0.01, respectively). On the contrary, the dose-volume of three-dimensional conformal radiotherapy at V20 was significantly smaller than those of linac-based intensity-modulated radiotherapy and helical tomotherapy in the remaining liver (P=0.03). Linac-based intensity-modulated radiotherapy showed better sparing of the stomach compared with helical tomotherapy in the case of separated lesions in both lobes (12.3 vs. 24.6 Gy). Helical tomotherapy showed the high dose-volume exposure to the left kidney due to helical delivery in the right lobe lesion. Helical tomotherapy achieved the best tumor coverage of the remaining normal liver. However, helical tomotherapy showed much exposure to the remaining liver at the lower dose region and left kidney. (author)

  16. Multi-centre experience of implementing image-guided intensity-modulated radiotherapy using the TomoTherapy platform

    International Nuclear Information System (INIS)

    Dean, J.C.; Tudor, G.S.J.; Mott, J.H.; Dunlop, P.R.; Morris, S.L.; Harron, E.C.; Christian, J.A.; Sanghera, P.; Elsworthy, M.; Burnet, N.G.

    2013-01-01

    Use of image guided (IG) intensity modulated radiotherapy (IMRT) is increasing, and helical tomotherapy provides an effective, integrated solution. Practical experience of implementation, shared at a recent UK TomoTherapy Users' meeting, may help centres introducing these techniques using TomoTherapy or other platforms. Seven centres participated, with data shared from 6, varying from 2500 - 4800 new patients per year. Case selection of patients “most likely” to benefit from IG-IMRT was managed in all centres by multi-professional groups comprising clinical oncologists, physicists, treatment planners and radiographers. Radical treatments ranged from 94% to 100%. The proportions of tumour types varied substantially: head and neck: range 0%–100% (mean of centres 50%), prostate: 3%–96% (mean of centres 28%). Head and neck cases were considered most likely to benefit from IMRT, prostate cases from IGRT, or IG-IMRT if pelvic nodes were being treated. IMRT was also selected for complex target volumes, to avoid field junctions, for technical treatment difficulties, and retreatments. Across the centres, every patient was imaged every day, with positional correction before treatment. In one centre, for prostate patients including pelvic treatment, the pelvis was also imaged weekly. All centres had designed a ‘ramp up’ of patient numbers, which was similar in 5. One centre, treating 96% prostate patients, started with 3 and increased to 36 patients per day within 3 months. The variation in case mix implies wide applicability of IG-IMRT. Daily on-line IGRT with IMRT can be routinely implemented into busy departments

  17. Intra-fraction motion of the prostate during treatment with helical tomotherapy

    International Nuclear Information System (INIS)

    Thomas, Simon J.; Ashburner, Mark; Tudor, George Samuel J.; Treeby, Jo; Dean, June; Routsis, Donna; Rimmer, Yvonne L.; Russell, Simon G.; Burnet, Neil G.

    2013-01-01

    Background and purpose: To measure the geometric uncertainty resulting from intra-fraction motion and intra-observer image matching, for patients having image-guided prostate radiotherapy on TomoTherapy. Material and methods: All patients had already been selected for prostate radiotherapy on TomoTherapy, with daily MV-CT imaging. The study involved performing an additional MV-CT image at the end of treatment, on 5 occasions during the course of 37 treatments. 54 patients were recruited to the study. A new formula was derived to calculate the PTV margin for intra-fraction motion. Results: The mean values of the intra-fraction differences were 0.0 mm, 0.5 mm, 0.5 mm and 0.0° for LR, SI, AP and roll, respectively. The corresponding standard deviations were 1.1 mm, 0.8 mm, 0.8 mm and 0.6° for systematic uncertainties (Σ), 1.3 mm, 2.0 mm, 2.2 mm and 0.3° for random uncertainties (σ). This intra-fraction motion requires margins of 2.2 mm in LR, 2.1 mm in SI and 2.1 mm in AP directions. Inclusion of estimates of the effect of rotations and matching errors increases these margins to approximately 4 mm in LR and 5 mm in SI and AP directions. Conclusions: A new margin recipe has been developed to calculate margins for intra-fraction motion. This recipe is applicable to any measurement technique that is based on the difference between images taken before and after treatment

  18. Helical Tomotherapy Planning for Left-Sided Breast Cancer Patients With Positive Lymph Nodes: Comparison to Conventional Multiport Breast Technique

    International Nuclear Information System (INIS)

    Goddu, S. Murty; Chaudhari, Summer; Mamalui-Hunter, Maria; Pechenaya, Olga L.; Pratt, David; Mutic, Sasa; Zoberi, Imran; Jeswani, Sam; Powell, Simon N.; Low, Daniel A.

    2009-01-01

    Purpose: To evaluate the feasibility of using helical tomotherapy for locally advanced left-sided breast cancer. Methods and Materials: Treatment plans were generated for 10 left-sided breast cancer patients with positive lymph nodes comparing a multiport breast (three-dimensional) technique with the tomotherapy treatment planning system. The planning target volumes, including the chest wall/breast, supraclavicular, axillary, and internal mammary lymph nodes, were contoured. The treatment plans were generated on the tomotherapy treatment planning system to deliver 50.4 Gy to the planning target volume. To spare the contralateral tissues, directional blocking was applied to the right breast and right lung. The optimization goals were to protect the lungs, heart, and right breast. Results: The tomotherapy plans increased the minimal dose to the planning target volume (minimal dose received by 99% of target volume = 46.2 ± 1.3 Gy vs. 27.9 ± 17.1 Gy) while improving the dose homogeneity (dose difference between the minimal dose received by 5% and 95% of the planning target volume = 7.5 ± 1.8 Gy vs. 37.5 ± 26.9 Gy). The mean percentage of the left lung volume receiving ≥20 Gy in the tomotherapy plans decreased from 32.6% ± 4.1% to 17.6% ± 3.5%, while restricting the right-lung mean dose to <5 Gy. However, the mean percentage of volume receiving ≥5 Gy for the total lung increased from 25.2% ± 4.2% for the three-dimensional technique to 46.9% ± 8.4% for the tomotherapy plan. The mean volume receiving ≥35 Gy for the heart decreased from 5.6% ± 4.8% to 2.2% ± 1.5% in the tomotherapy plans. However, the mean heart dose for tomotherapy delivery increased from 7.5 ± 3.4 Gy to 12.2 ± 1.8 Gy. Conclusion: The tomotherapy plans provided better dose conformity and homogeneity than did the three-dimensional plans for treatment of left-sided breast tumors with regional lymph node involvement, while allowing greater sparing of the heart and left lung from doses

  19. Dosimetric effects of rotational output variation and x-ray target degradation on helical tomotherapy plans

    International Nuclear Information System (INIS)

    Staton, Robert J.; Langen, Katja M.; Kupelian, Patrick A.; Meeks, Sanford L.

    2009-01-01

    In this study, two potential sources of IMRT delivery error have been identified for helical tomotherapy delivery using the HiART system (TomoTherapy, Inc., Madison, WI): Rotational output variation and target degradation. The HiArt system is known to have output variation, typically about ±2%, due to the absence of a dose servo system. On the HiArt system, x-ray target replacement is required approximately every 10-12 months due to target degradation. Near the end of target life, the target thins and causes a decrease in the beam energy and a softening of the beam profile at the lateral edges of the beam. The purpose of this study is to evaluate the dosimetric effects of rotational output variation and target degradation by modeling their effects and incorporating them into recalculated treatment plans for three clinical scenarios: Head and neck, partial breast, and prostate. Models were created to emulate both potential sources of error. For output variation, a model was created using a sine function to match the amplitude (±2%), frequency, and phase of the measured rotational output variation data. A second model with a hypothetical variation of ±7% was also created to represent the largest variation that could exist without violating the allowable dose window in the delivery system. A measured beam profile near the end of target life was used to create a modified beam profile model for the target degradation. These models were then incorporated into the treatment plan by modifying the leaf opening times in the delivery sinogram. A new beam model was also created to mimic the change in beam energy seen near the end of target life. The plans were then calculated using a research version of the PLANNED ADAPTIVE treatment planning software from TomoTherapy, Inc. Three plans were evaluated in this study: Head and neck, partial breast, and prostate. The D 50 of organs at risk, the D 95 for planning target volumes (PTVs), and the local dose difference were used to

  20. Prostate cancer treated with image-guided helical TomoTherapy {sup registered} and image-guided LINAC-IMRT. Correlation between high-dose bladder volume, margin reduction, and genitourinary toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Drozdz, Sonia; Wendt, Thomas G. [University Hospital Jena, Friedrich-Schiller-University Jena, Department of Radiation Oncology, Jena (Germany); Schwedas, Michael; Salz, Henning [University Hospital Jena, Friedrich-Schiller-University Jena, Department of Radiation Oncology, Section of Medical Physics, Jena (Germany); Foller, Susan [University Hospital Jena, Friedrich-Schiller-University Jena, Department of Urology, Jena (Germany)

    2016-04-15

    We compared different image-guidance (IG) strategies for prostate cancer with high-precision IG intensity-modulated radiation therapy (IMRT) using TomoTherapy {sup registered} (Accuray Inc., Madison, WI, USA) and linear accelerator (LINAC)-IMRT and their impact on planning target volume (PTV) margin reduction. Follow-up data showed reduced bladder toxicity in TomoTherapy patients compared to LINAC-IMRT. The purpose of this study was to quantify whether the treatment delivery technique and decreased margins affect reductions in bladder toxicity. Setup corrections from 30 patients treated with helical TomoTherapy and 30 treated with a LINAC were analyzed. These data were used to simulate three IG protocols based on setup error correction and a limited number of imaging sessions. For all patients, gastrointestinal (GI) and genitourinary (GU) toxicity was documented and correlated with the treatment delivery technique. For fiducial marker (FM)-based RT, a margin reduction of up to 3.1, 3.0, and 4.8 mm in the left-right (LR), superior-inferior (SI), and anterior-posterior (AP) directions, respectively, could be achieved with calculation of a setup correction from the first three fractions and IG every second day. Although the bladder volume was treated with mean doses of 35 Gy in the TomoTherapy group vs. 22 Gy in the LINAC group, we observed less GU toxicity after TomoTherapy. Intraprostate FMs allow for small safety margins, help decrease imaging frequency after setup correction, and minimize the dose to bladder and rectum, resulting in lower GU toxicity. In addition, IMRT delivered with TomoTherapy helps to avoid hotspots in the bladder neck, a critical anatomic structure associated with post-RT urinary toxicity. (orig.) [German] Wir haben im Rahmen der Prostatakarzinombehandlung verschiedene bildgefuehrte (IG) Strategien der hochpraezisen intensitaetsmodulierten Radiotherapie (IMRT) unter Einsatz der Tomotherapie (TomoTherapy {sup registered}, Accuray Inc., Madison

  1. Comparison of the effectiveness of different immobilization systems in different body regions using daily megavoltage CT in helical tomotherapy

    Science.gov (United States)

    Cheng, K-F

    2014-01-01

    Objective: Effective immobilization is crucial for the accurate delivery of radiotherapy. This study aimed to compare the effectiveness of the commonly used immobilization systems for different body regions using megavoltage CT (MVCT). Methods: Daily treatment set-up data from 212 patients treated by helical tomotherapy (Accuray, Sunnyvale, CA) in 6 body regions (52 head and neck, 41 chest, 38 abdomen, 36 pelvis, 18 breast and 27 cranium) were obtained. Based on a verification tool using the pre-treatment MVCT, set-up corrections for each patient were recorded. Mean systematic and random errors of lateral, longitudinal, vertical and roll directions and three-dimensional vectors were compared between immobilization systems of each region. Results: Smaller set-up deviations were observed in the Orfit system (Orfit Industries NV, Wijnegem, Belgium) of the head and neck region, while the performance of immobilization systems for the chest, abdomen and pelvis regions was similar. Larger differences were noted in the breast group, where the prone BodyFIX® system (Medical Intelligence, Medizintechnik GmbH, Schwabmünchen, Germany) was less stable than the supine VacLok® system (CIVCO Medical Solutions, Orange City, IA). Conclusion: Differences were found between the immobilization systems in the head and neck region, in which the Orfit system was relatively more effective, whereas the VacLok and BodyFIX systems performed similarly in the chest, abdomen and pelvis regions. For the breast case, the supine position with VacLok was much more stable than the prone breast technique. The results provided references for the estimation of clinical target volume–planning target volume margins. Advances in knowledge: This is the first article on comprehensive comparisons performed in immobilization systems for main body regions that provides some practical recommendations. PMID:24398111

  2. An assessment of the use of skin flashes in helical tomotherapy using phantom and in-vivo dosimetry

    International Nuclear Information System (INIS)

    Tournel, Koen; Verellen, Dirk; Duchateau, Michael; Fierens, Yves; Linthout, Nadine; Reynders, Truus; Voordeckers, Mia; Storme, Guy

    2007-01-01

    Background and purpose: In helical tomotherapy the nature of the optimizing and planning systems allows the delivery of dose on the skin using a build-up compensating technique (skin flash). However, positioning errors or changes in the patient's contour can influence the correct dosage in these regions. This work studies the behavior of skin-flash regions using phantom and in-vivo dosimetry. Materials and methods: The dosimetric accuracy of the tomotherapy planning system in skin-flash regions is checked using film and TLD on phantom. Positioning errors are induced and the effect on the skin dose is investigated. Further a volume decrease is simulated using bolus material and the results are compared. Results: Results show that the tomotherapy planning system calculates dose on skin regions within 2 SD using TLD measurements. Film measurements show drops of dose of 2.8% and 26% for, respectively, a 5 mm and 10 mm mispositioning of the phantom towards air and a dose increase of 9% for a 5 mm shift towards tissue. These measurements are confirmed by TLD measurements. A simulated volume reduction shows a similar behavior with a 2.6% and 19.4% drop in dose, measured with TLDs. Conclusion: The tomotherapy system allows adequate planning and delivery of dose using skin flashes. However, exact positioning is crucial to deliver the dose at the exact location

  3. Development of a software tool for the management of quality control in a helical tomotherapy unit; Desarrollo de una herramienta de software para la gestion integral del control de calidad en una unidad de tomoterapia helicoidal

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Repiso, S.; Hernandez Rodriguez, J.; Martin Rincon, C.; Ramos Pacho, J. A.; Verde Velasco, J. M.; Delgado Aparacio, J. M.; Perez Alvarez, M. e.; Gomez Gonzalez, N.; Cons Perez, V.; Saez Beltran, M.

    2013-07-01

    The large amount of data and information that is managed in units of external radiotherapy quality control tests makes necessary the use of tools that facilitate, on the one hand, the management of measures and results in real time, and on other tasks of management, file, query and reporting of stored data. This paper presents an application of software of own development which is used for the integral management of the helical TomoTherapy unit in the aspects related to the roles and responsibilities of the hospital Radiophysics. (Author)

  4. Tumor cell survival dependence on helical tomotherapy, continuous arc and segmented dose delivery

    International Nuclear Information System (INIS)

    Yang Wensha; Wang Li; Larner, James; Read, Paul; Benedict, Stan; Sheng Ke

    2009-01-01

    The temporal pattern of radiation delivery has been shown to influence the tumor cell survival fractions for the same radiation dose. To study the effect more specifically for state of the art rotational radiation delivery modalities, 2 Gy of radiation dose was delivered to H460 lung carcinoma, PC3 prostate cancer cells and MCF-7 breast tumor cells by helical tomotherapy (HT), seven-field LINAC (7F), and continuous dose delivery (CDD) over 2 min that simulates volumetric rotational arc therapy. Cell survival was measured by the clonogenic assay. The number of viable H460 cell colonies was 23.2 ± 14.4% and 27.7 ± 15.6% lower when irradiated by CDD compared with HT and 7F, respectively, and the corresponding values were 36.8 ± 18.9% and 35.3 ± 18.9% lower for MCF7 cells (p < 0.01). The survival of PC3 was also lower when irradiated by CDD than by HT or 7F but the difference was not as significant (p = 0.06 and 0.04, respectively). The higher survival fraction from HT delivery was unexpected because 90% of the 2 Gy was delivered in less than 1 min at a significantly higher dose rate than the other two delivery techniques. The results suggest that continuous dose delivery at a constant dose rate results in superior in vitro tumor cell killing compared with prolonged, segmented or variable dose rate delivery.

  5. Preliminary comp arison of helical tomotherapy and mixed beams of unmodulated electrons and intensity modulated radiation therapy for treating superficial cancers of the parotid gland and nasal cavity

    International Nuclear Information System (INIS)

    Blasi, Olivier; Fontenot, Jonas D; Fields, Robert S; Gibbons, John P; Hogstrom, Kenneth R

    2011-01-01

    To investigate combining unmodulated electron beams with intensity-modulated radiation therapy to improve dose distributions for superficial head and neck cancers, and to compare mixed beam plans with helical tomotherapy. Mixed beam and helical tomotherapy dose plans were developed for two patients with parotid gland tumors and two patients with nasal cavity tumors. Mixed beam plans consisted of various weightings of a enface electron beam and IMRT, which was optimized after calculation of the electron dose to compensate for heterogeneity in the electron dose distribution within the target volume. Helical tomotherapy plans showed dose conformity and homogeneity in the target volume that was equal to or better than the mixed beam plans. Electron-only plans tended to show the lowest doses to normal tissues, but with markedly worse dose conformity and homogeneity than in the other plans. However, adding a 20% IMRT dose fraction (i.e., IMRT:electron weighting = 1:4) to the electron plan restored target conformity and homogeneity to values comparable to helical tomotherapy plans, while maintaining lower normal tissue dose. Mixed beam treatments offer some dosimetric advantages over IMRT or helical tomotherapy for target depths that do not exceed the useful range of the electron beam. Adding a small IMRT component (e.g., IMRT:electron weighting = 1:4) to electron beam plans markedly improved target dose homogeneity and conformity for the cases examined in this study

  6. Image-guided total-marrow irradiation using helical tomotherapy in patients with multiple myeloma and acute leukemia undergoing hematopoietic cell transplantation.

    Science.gov (United States)

    Wong, Jeffrey Y C; Rosenthal, Joseph; Liu, An; Schultheiss, Timothy; Forman, Stephen; Somlo, George

    2009-01-01

    Total-body irradiation (TBI) has an important role in patients undergoing hematopoietic cell transplantation (HCT), but is associated with significant toxicities. Targeted TBI using helical tomotherapy results in reduced doses to normal organs, which predicts for reduced toxicities compared with standard TBI. Thirteen patients with multiple myeloma were treated in an autologous tandem transplantation Phase I trial with high-dose melphalan, followed 6 weeks later by total-marrow irradiation (TMI) to skeletal bone. Dose levels were 10, 12, 14, and 16 Gy at 2 Gy daily/twice daily. In a separate allogeneic HCT trial, 8 patients (5 with acute myelogenous leukemia, 1 with acute lymphoblastic leukemia, 1 with non-Hodgkin's lymphoma, and 1 with multiple myeloma) were treated with TMI plus total lymphoid irradiation plus splenic radiotherapy to 12 Gy (1.5 Gy twice daily) combined with fludarabine/melphalan. For the 13 patients in the tandem autologous HCT trial, median age was 54 years (range, 42-66 years). Median organ doses were 15-65% that of the gross target volume dose. Primarily Grades 1-2 acute toxicities were observed. Six patients reported no vomiting; 9 patients, no mucositis; 6 patients, no fatigue; and 8 patients, no diarrhea. For the 8 patients in the allogeneic HCT trial, median age was 52 years (range, 24-61 years). Grades 2-3 nausea, vomiting, mucositis, and diarrhea were observed. In both trials, no Grade 4 nonhematologic toxicity was observed, and all patients underwent successful engraftment. This study shows that TMI using helical tomotherapy is clinically feasible. The reduced acute toxicities observed compare favorably with those seen with standard TBI. Initial results are encouraging and warrant further evaluation as a method to dose escalate with acceptable toxicity or to offer TBI-containing regimens to patients unable to tolerate standard approaches.

  7. Image-Guided Total-Marrow Irradiation Using Helical Tomotherapy in Patients With Multiple Myeloma and Acute Leukemia Undergoing Hematopoietic Cell Transplantation

    International Nuclear Information System (INIS)

    Wong, Jeffrey Y.C.; Rosenthal, Joseph; Liu An; Schultheiss, Timothy; Forman, Stephen; Somlo, George

    2009-01-01

    Purpose: Total-body irradiation (TBI) has an important role in patients undergoing hematopoietic cell transplantation (HCT), but is associated with significant toxicities. Targeted TBI using helical tomotherapy results in reduced doses to normal organs, which predicts for reduced toxicities compared with standard TBI. Methods and Materials: Thirteen patients with multiple myeloma were treated in an autologous tandem transplantation Phase I trial with high-dose melphalan, followed 6 weeks later by total-marrow irradiation (TMI) to skeletal bone. Dose levels were 10, 12, 14, and 16 Gy at 2 Gy daily/twice daily. In a separate allogeneic HCT trial, 8 patients (5 with acute myelogenous leukemia, 1 with acute lymphoblastic leukemia, 1 with non-Hodgkin's lymphoma, and 1 with multiple myeloma) were treated with TMI plus total lymphoid irradiation plus splenic radiotherapy to 12 Gy (1.5 Gy twice daily) combined with fludarabine/melphalan. Results: For the 13 patients in the tandem autologous HCT trial, median age was 54 years (range, 42-66 years). Median organ doses were 15-65% that of the gross target volume dose. Primarily Grades 1-2 acute toxicities were observed. Six patients reported no vomiting; 9 patients, no mucositis; 6 patients, no fatigue; and 8 patients, no diarrhea. For the 8 patients in the allogeneic HCT trial, median age was 52 years (range, 24-61 years). Grades 2-3 nausea, vomiting, mucositis, and diarrhea were observed. In both trials, no Grade 4 nonhematologic toxicity was observed, and all patients underwent successful engraftment. Conclusions: This study shows that TMI using helical tomotherapy is clinically feasible. The reduced acute toxicities observed compare favorably with those seen with standard TBI. Initial results are encouraging and warrant further evaluation as a method to dose escalate with acceptable toxicity or to offer TBI-containing regimens to patients unable to tolerate standard approaches

  8. Clinical observation in nasopharyngeal carcinoma (NPC) treated with the anti-EGFR monoclonal antibody followed by helical tomotherapy

    International Nuclear Information System (INIS)

    Hou Jun; Feng Linchun; Cai Boning; Lu Na; Du Lei; Ma Lin; Xu Shouping; Xie Chuanbin

    2011-01-01

    Objective: To evaluate the clinical outcome and the acute toxicity in nasopharyngeal carcinoma (NPC) treated with tomotherapy followed by the anti-EGFR monoclonal antibody. Methods: Between March 2008 and November 2009, 34 newly diagnosed NPC patients were treated with helical tomotherapy combined with nimotuzumab or cetuximab. All the patients underwent tomotherapy at the dose of 70 Gy/33F for the gross tumor volume (pGTV ns ) and positive lymphnodes (GTV nd ), and 60 Gy/33F for the high risk clinical target volume (PTV 1 ), and 56 Gy/33 F for the low risk clinical target volume (PTV 2 ), respectively. 17 patients in group N were given weekly injection of 200 mg for 6-7 times and 17 patients in group C were given initial dosage 400 mg/m 2 followed by subsequent weekly dosage of 250 mg/m 2 for 6-7 times. Acute lesions were evaluated with the RTOG/EORTC criteria. Result: The median follow-up time was 22 months. The effective rates (CR + PR) in 3, 6 and 12 months were 14/17, 12/17, 12/17 in group N and 15/17, 14/17, 14/17 in group C. The 1 year survival rate was 15/17 in group Nand 17/17 in group C. Nimotuzumab had less acute mucositis reaction (u=2.25, P< 0.05), weight loss (t=2.56, P=0.02) and rash (u=4.36, P<0.01) compared with cetuximab. Conclusions: Helical tomotherapy combined with nimotuzumab or cetuximab was effective and made no difference in the short-term efficacy and 1 year survival rate for the patients with NPC. Nimotuzumab has less acute reaction than cetuximab. More studies should be done to prove long-term effects. (authors)

  9. Helical Tomotherapy Planning for Lung Cancer Based on Ventilation Magnetic Resonance Imaging

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    Cai Jing; McLawhorn, Robert [Department of Radiation Oncology, University of Virginia, Charlottesville, VA (United States); Altes, Tallisa A.; Lange, Eduard de [Department of Radiology, University of Virginia, Charlottesville, VA (United States); Read, Paul W.; Larner, James M.; Benedict, Stanley H. [Department of Radiation Oncology, University of Virginia, Charlottesville, VA (United States); Sheng Ke, E-mail: ks2mc@virginia.edu [Department of Radiation Oncology, University of Virginia, Charlottesville, VA (United States)

    2011-01-01

    To investigate the feasibility of lung ventilation-based treatment planning, computed tomography and hyperpolarized (HP) helium-3 (He-3) magnetic resonance imaging (MRI) ventilation images of 6 subjects were coregistered for intensity-modulated radiation therapy planning in Tomotherapy. Highly-functional lungs (HFL) and less-functional lungs (LFL) were contoured based on their ventilation image intensities, and a cylindrical planning-target-volume was simulated at locations adjacent to both HFL and LFL. Annals of an anatomy-based plan (Plan 1) and a ventilation-based plan (Plan 2) were generated. The following dosimetric parameters were determined and compared between the 2 plans: percentage of total/HFL volume receiving {>=}20 Gy, 15 Gy, 10 Gy, and 5 Gy (TLV{sub 20}, HFLV{sub 20}, TLV{sub 15}, HFLV{sub 15}, TLV{sub 10}, HFLV{sub 10}, TLV{sub 5}, HFLV{sub 5}), mean total/HFL dose (MTLD/HFLD), maximum doses to all organs at risk (OARs), and target dose conformality. Compared with Plan 1, Plan 2 reduced mean HFLD (mean reduction, 0.8 Gy), MTLD (mean reduction, 0.6 Gy), HFLV{sub 20} (mean reduction, 1.9%), TLV{sub 20} (mean reduction, 1.5%), TLV{sub 15} (mean reduction, 1.7%), and TLV{sub 10} (mean reduction, 2.1%). P-values of the above comparisons are less than 0.05 using the Wilcoxon signed rank test. For HFLV{sub 15}, HFLV{sub 10}, TLV{sub 5}, and HTLV{sub 5}, Plan 2 resulted in lower values than plan 1 but the differences are not significant (P-value range, 0.063-0.219). Plan 2 did not significantly change maximum doses to OARs (P-value range, 0.063-0.563) and target conformality (P = 1.000). HP He-3 MRI of patients with lung disease shows a highly heterogeneous ventilation capacity that can be utilized for functional treatment planning. Moderate but statistically significant improvements in sparing functional lungs were achieved using helical tomotherapy plans.

  10. Dosimetric comparison of helical tomotherapy, RapidArc, and a novel IMRT and Arc technique for esophageal carcinoma

    International Nuclear Information System (INIS)

    Martin, Spencer; Chen, Jeff Z.; Rashid Dar, A.; Yartsev, Slav

    2011-01-01

    Purpose: To compare radiotherapy treatment plans for mid- and distal-esophageal cancer with primary involvement of the gastroesophageal (GE) junction using a novel IMRT and Arc technique (IMRT and Arc), helical tomotherapy (HT), and RapidArc (RA1 and RA2). Methods and materials: Eight patients treated on HT for locally advanced esophageal cancer with radical intent were re-planned for RA and IMRT and Arc. RA plans employed single and double arcs (RA1 and RA2, respectively), while IMRT and Arc plans had four fixed-gantry IMRT fields and a conformal arc. Dose-volume histogram statistics, dose uniformity, and dose homogeneity were analyzed to compare treatment plans. Results: RA2 plans showed significant improvement over RA1 plans in terms of OAR dose and PTV dose uniformity and homogeneity. HT plan provided best dose uniformity (p = 0.001) and dose homogeneity (p = 0.002) to planning target volume (PTV), while IMRT and Arc and RA2 plans gave lowest dose to lungs among four radiotherapy techniques with acceptable PTV dose coverage. Mean V 10 of the lungs was significantly reduced by the RA2 plans compared to IMRT and Arc (40.3%, p = 0.001) and HT (66.2%, p 15 of the lungs for the RA2 plans also showed significant improvement over the IMRT and Arc (25.2%, p = 0.042) and HT (34.8%, p = 0.027) techniques. These improvements came at the cost of higher doses to the heart volume compared to HT and IMRT and Arc techniques. Mean lung dose (MLD) for the IMRT and Arc technique (21.2 ± 5.0% of prescription dose) was significantly reduced compared to HT (26.3%, p = 0.004), RA1 (23.3%, p = 0.028), and RA2 (23.2%, p = 0.017) techniques. Conclusion: The IMRT and Arc technique is a good option for treating esophageal cancer with thoracic involvement. It achieved optimal low dose to the lungs and heart with acceptable PTV coverage. HT is a good option for treating esophageal cancer with little thoracic involvement as it achieves superior dose conformality and uniformity. The RA2

  11. Clinical effectiveness, toxicity, and failure patterns of helical tomotherapy for postoperative oral cavity cancer patients

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    Hsieh CH

    2014-03-01

    Full Text Available Chen-Hsi Hsieh,1–3 Pei-Wei Shueng,1,4 Li-Ying Wang,5 Li-Jen Liao,6 Yu-Chin Lin,7 Ying-Shiung Kuo,8 Wu-Chia Lo,6 Chien-Fu Tseng,8 Hui-Ju Tien,1 Hsiu-Ling Chou,9,10 Yen-Ping Hsieh,11 Le-Jung Wu,1 Yu-Jen Chen3,12–14 1Department of Radiation Oncology, Far Eastern Memorial Hospital, 2Department of Medicine, 3Institute of Traditional Medicine, School of Medicine, National Yang-Ming University, 4Department of Radiation Oncology, National Defense Medical Center, 5School and Graduate Institute of Physical Therapy, College of Medicine, National Taiwan University, 6Department of Otolaryngology, 7Division of Medical Oncology and Hematology, Department of Internal Medicine, 8Department of Dentistry and Oral Surgery, 9Department of Nursing, Far Eastern Memorial Hospital, 10Department of Nursing, Oriental Institute of Technology, Taipei, 11Department of Senior Citizen Service Management, National Taichung University of Science and Technology, Taichung, 12Department of Radiation Oncology, 13Department of Medical Research, Mackay Memorial Hospital, 14Graduate Institute of Sport Coaching Science, Chinese Culture University, Taipei, Taiwan Background: The outcome of postoperative high- and intermediate-risk oral cavity cancer (OCC patients receiving helical tomotherapy (HT remains limited. Materials and methods: Between November 2006 and November 2012, 53 postoperative high- and intermediate-risk OCC patients treated with HT were enrolled. Results: The 4-year locoregional, local, and regional control rates were 66%, 76.4%, and 94.3%, respectively. The 4-year locoregional control rates of oral tongue and buccal mucosa cancer were 88.3% and 37.1%, respectively (P=0.012. Eleven (20.8% patients experienced locoregional failure. In-field failure occurred in six of 53 (11.3% in the primary area and three of 53 (5.7% in the regional lymph-node area. No marginal failure was noted. Two of 53 (3.8% experienced out-of-field failure. The rates of grade 3 dermatitis

  12. Feasibility and response of helical tomotherapy in patients with metastatic colorectal cancer

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    Kim, Yong Ho [Dept. of Radiation Oncology, Catholic Kwandong University International St. Mary' s Hospital, Incheon (Korea, Republic of); Bae, Sun yun; Moon, Seong Kwon; Cho, Kwang Hwan; Shin, Eung Jin; Lee, Moon Sung; Ryu, Chang Beom; Ko, Bong Min; Yun, Ji Na [Soonchunhyang University College of Medicine, Bucheon (Korea, Republic of)

    2015-12-15

    To investigate the treatment outcome and the toxicity of helical tomotherapy (HT) in patients with metastatic colorectal cancer (mCRC). We retrospectively reviewed 18 patients with 31 lesions from mCRC treated with HT between 2009 and 2013. The liver (9 lesions) and lymph nodes (9 lesions) were the most frequent sites. The planning target volume (PTV) ranged from 12 to 1,110 mL (median, 114 mL). The total doses ranged from 30 to 70 Gy in 10-30 fractions. When the alpha/beta value for the tumor was assumed to be 10 Gy for the biologically equivalent dose (BED), the total doses ranged from 39 to 119 Gy{sub 10} (median, 55 Gy{sub 10}). Nineteen lesions were treated with concurrent chemotherapy (CCRT). With a median follow-up time of 16 months, the median overall survival for 18 patients was 33 months. Eight lesions (26%) achieved complete response. The 1- and 3-year local progression free survival (LPFS) rates for 31 lesions were 45% and 34%, respectively. On univariate analysis, significant parameters influencing LPFS rates were chemotherapy response before HT, aim of HT, CCRT, PTV, BED, and adjuvant chemotherapy. On multivariate analysis, PTV < or =113 mL and BED >48 Gy{sub 10} were associated with a statistically significant improvement in LFPS. During HT, four patients experienced grade 3 hematologic toxicities, each of whom had also received CCRT. The current study demonstrates the efficacy and tolerability of HT for mCRC. To define optimal RT dose according to tumor size of mCRC, further study should be needed.

  13. Feasibility of Helical Tomotherapy for Debulking Irradiation Before Stem Cell Transplantation in Malignant Lymphoma

    International Nuclear Information System (INIS)

    Chargari, Cyrus; Vernant, Jean-Paul; Tamburini, Jerome; Zefkili, Sofia; Fayolle, Maryse; Campana, Francois; Fourquet, Alain; Kirova, Youlia M.

    2011-01-01

    Purpose: Preliminary clinical experience has suggested that radiation therapy (RT) may be effectively incorporated into conditioning therapy before transplant for patients with refractory/relapsed malignant lymphoma. We investigated the feasibility of debulking selective lymph node irradiation before autologous and/or allogeneic stem cell transplantation (SCT) using helical tomotherapy (HT). Methods and Materials: Six consecutive patients with refractory malignant lymphoma were referred to our institution for salvage HT before SCT. All patients had been previously heavily treated but had bulky residual tumor despite chemotherapy (CT) intensification. Two patients had received previous radiation therapy. HT delivered 30-40 Gy in the involved fields (IF), using 6 MV photons, 2 Gy per daily fraction. Total duration of treatment was 28 to 35 days. Results: Using HT, doses to critical organs (heart, lungs, esophagu, and parotids) were significantly decreased and highly conformational irradiation could be delivered to all clinical target volumes. HT delivery was technically possible, even in patients with lesions extremely difficult to irradiate in other conditions or in patients with previous radiation therapy. No Grade 2 or higher toxicity occurred. Four months after the end of HT, 5 patients experienced complete clinical, radiologic, and metabolic response and were subsequently referred for SCT. Conclusions: By more effectively sparing critical organs, HT may contribute to improving the tolerance of debulking irradiation before allograft. Quality of life may be preserved, and doses to the heart may be decreased. This is particularly relevant in heavily treated patients who are at risk for subsequent heart disease. These preliminary results require further prospective assessment.

  14. Split-Field Helical Tomotherapy With or Without Chemotherapy for Definitive Treatment of Cervical Cancer

    International Nuclear Information System (INIS)

    Chang, Albert J.; Richardson, Susan; Grigsby, Perry W.; Schwarz, Julie K.

    2012-01-01

    Objective: The objective of this study was to investigate the chronic toxicity, response to therapy, and survival outcomes of patients with cervical cancer treated with definitive pelvic irradiation delivered by helical tomotherapy (HT), with or without concurrent chemotherapy. Methods and Materials: There were 15 patients with a new diagnosis of cervical cancer evaluated in this study from April 2006 to February 2007. The clinical stages of their disease were Stage Ib1 in 3 patients, Ib2 in 3, IIa in 2, IIb in 4, IIIb in 2, and IVa in 1 patient. Fluorodeoxyglucose–positron emission tomography/computed tomography (FDG-PET/CT) simulation was performed in all patients. All patients received pelvic irradiation delivered by HT and high-dose-rate (HDR) brachytherapy. Four patients also received para-aortic irradiation delivered by HT. Thirteen patients received concurrent chemotherapy. Patients were monitored for chronic toxicity using the Common Terminology Criteria for Adverse Events version 3.0 criteria. Results: The median age of the cohort was 51 years (range, 29-87 years), and the median follow-up for all patients alive at time of last follow-up was 35 months. The median overall radiation treatment time was 54 days. One patient developed a chronic Grade 3 GI complication. No other Grade 3 or 4 complications were observed. At last follow-up, 3 patients had developed a recurrence, with 1 patient dying of disease progression. The 3-year progression-free and cause-specific survival estimates for all patients were 80% and 93%, respectively. Conclusion: Intensity-modulated radiation therapy delivered with HT and HDR brachytherapy with or without chemotherapy for definitive treatment of cervical cancer is feasible, with acceptable levels of chronic toxicity.

  15. Preliminary analysis of risk factors for late rectal toxicity after helical tomotherapy for prostate cancer

    International Nuclear Information System (INIS)

    Tomita, Natsuo; Soga, Norihito; Ogura, Yuji

    2013-01-01

    The purpose of this study is to examine risk factors for late rectal toxicity for localized prostate cancer patients treated with helical tomotherapy (HT). The patient cohort of this retrospective study was composed of 241 patients treated with HT and followed up regularly. Toxicity levels were scored according to the Radiation Therapy Oncology Group grading scale. The clinical and dosimetric potential factors increasing the risk of late rectal toxicity, such as age, diabetes, anticoagulants, prior abdominal surgery, prescribed dose, maximum dose of the rectum, and the percentage of the rectum covered by 70 Gy (V70), 60 Gy (V60), 40 Gy (V40) and 20 Gy (V20) were compared between ≤ Grade 1 and ≥ Grade 2 toxicity groups using the Student's t-test. Multivariable logistic regression analysis of the factors that appeared to be associated with the risk of late rectal toxicity (as determined by the Student's t-test) was performed. The median follow-up time was 35 months. Late Grade 2-3 rectal toxicity was observed in 18 patients (7.4%). Age, the maximum dose of the rectum, V70 and V60 of the ≥ Grade 2 toxicity group were significantly higher than in those of the ≤ Grade 1 toxicity group (P=0.00093, 0.048, 0.0030 and 0.0021, respectively). No factor was significant in the multivariable analysis. The result of this study indicates that the risk of late rectal toxicity correlates with the rectal volume exposed to high doses of HT for localized prostate cancer. Further follow-up and data accumulation may establish dose-volume modeling to predict rectal complications after HT. (author)

  16. A Monte Carlo derived TG-51 equivalent calibration for helical tomotherapy

    International Nuclear Information System (INIS)

    Thomas, S.D.; Mackenzie, M.; Rogers, D.W.O.; Fallone, B.G.

    2005-01-01

    Helical tomotherapy (HT) requires a method of accurately determining the absorbed dose under reference conditions. In the AAPM's TG-51 external beam dosimetry protocol, the quality conversion factor, k Q , is presented as a function of the photon component of the percentage depth-dose at 10 cm depth, %dd(10) x , measured under the reference conditions of a 10x10 cm 2 field size and a source-to-surface distance (SSD) of 100 cm. The value of %dd(10) x from HT cannot be used for the determination of k Q because the design of the HT does not meet the following TG-51 reference conditions: (i) the field size and the practical SSD required by TG-51 are not obtainable and (ii) the absence of the flattening filter changes the beam quality thus affecting some components of k Q . The stopping power ratio is not affected because of its direct relationship to %dd(10) x . We derive a relationship for the Exradin A1SL ion chamber converting the %dd(10) x measured under HT 'reference conditions' of SSD=85 cm and a 5x10 cm 2 field-size [%dd(10) x[HTRef] ], to the dosimetric equivalent value under for TG-51 reference conditions [%dd(10) x[HTTG-51] ] for HT. This allows the determination of k Q under the HT reference conditions. The conversion results in changes of 0.1% in the value of k Q for our particular unit. The conversion relationship should also apply to other ion chambers with possible errors on the order of 0.1%

  17. Validation of a computational method for assessing the impact of intra-fraction motion on helical tomotherapy plans

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    Ngwa, Wilfred; Meeks, Sanford L; Kupelian, Patrick A; Langen, Katja M [Department of Radiation Oncology, M D Anderson Cancer Center Orlando, 1400 South Orange Avenue, Orlando, FL 32806 (United States); Schnarr, Eric [TomoTherapy, Inc., 1240 Deming Way, Madison, WI 53717 (United States)], E-mail: wilfred.ngwa@orlandohealth.com

    2009-11-07

    In this work, a method for direct incorporation of patient motion into tomotherapy dose calculations is developed and validated. This computational method accounts for all treatment dynamics and can incorporate random as well as cyclical motion data. Hence, interplay effects between treatment dynamics and patient motion are taken into account during dose calculation. This allows for a realistic assessment of intra-fraction motion on the dose distribution. The specific approach entails modifying the position and velocity events in the tomotherapy delivery plan to accommodate any known motion. The computational method is verified through phantom and film measurements. Here, measured prostate motion and simulated respiratory motion tracks were incorporated in the dose calculation. The calculated motion-encoded dose profiles showed excellent agreement with the measurements. Gamma analysis using 3 mm and 3% tolerance criteria showed over 97% and 96% average of points passing for the prostate and breathing motion tracks, respectively. The profile and gamma analysis results validate the accuracy of this method for incorporating intra-fraction motion into the dose calculation engine for assessment of dosimetric effects on helical tomotherapy dose deliveries.

  18. Intensity-modulated radiation therapy using static ports of tomotherapy (TomoDirect): comparison with the TomoHelical mode

    International Nuclear Information System (INIS)

    Murai, Taro; Shibamoto, Yuta; Manabe, Yoshihiko; Murata, Rumi; Sugie, Chikao; Hayashi, Akihiro; Ito, Hiroya; Miyoshi, Yoshihito

    2013-01-01

    With the new mode of Tomotherapy, irradiation can be delivered using static ports of the TomoDirect mode. The purpose of this study was to evaluate the characteristics of TomoDirect plans compared to conventional TomoHelical plans. TomoDirect and TomoHelical plans were compared in 46 patients with a prostate, thoracic wall or lung tumor. The mean target dose was used as the prescription dose. The minimum coverage dose of 95% of the target (D95%), conformity index (CI), uniformity index (UI), dose distribution in organs at risk and treatment time were evaluated. For TomoDirect, 2 to 5 static ports were used depending on the tumor location. For the prostate target volume, TomoDirect plans could not reduce the rectal dose and required a longer treatment time than TomoHelical. For the thoracic wall target volume, the V5Gy of the lung or liver was lower in TomoDirect than in TomoHelical (p = 0.02). For the lung target volume, TomoDirect yielded higher CI (p = 0.009) but smaller V5Gy of the lung (p = 0.005) than TomoHelical. Treatment time did not differ significantly between the thoracic wall and lung plans. Prostate cancers should be treated with the TomoHelical mode. Considering the risk of low-dose radiation to the lung, the TomoDirect mode could be an option for thoracic wall and lung tumors

  19. Results of a two-year quality control program for a helical tomotherapy unit

    International Nuclear Information System (INIS)

    Broggi, Sara; Mauro Cattaneo, Giovanni; Molinelli, Silvia; Maggiulli, Eleonora; Del Vecchio, Antonella; Longobardi, Barbara; Perna, Lucia; Fazio, Ferruccio; Calandrino, Riccardo

    2008-01-01

    Background and purpose: Image-guided helical tomotherapy (HT) is a new modality for delivering intensity modulated radiation therapy (IMRT) with helical irradiation: the slip ring continuously rotates while the couch moves into the bore. The radiation source (Linac, 6 MV) is collimated into a fan beam and modulated by means of a binary multileaf collimator (MLC). A xenon detector array, opposite the radiation source, allows a megavoltage-CT (MVCT) acquisition of patient images for set-up verification. The aim of this paper is to report the results of a two-year quality control (QC) program for the physical and dosimetric characterization of an HT unit installed at our Institute and clinically activated in November 2004, in order to monitor and verify the stability and the reliability of this promising radiation treatment unit. Materials and methods: Conventional Linac acceptance protocols (ATP) and QC protocols were adapted to HT with the addition of specific items reflecting important differences between the two irradiation modalities. QC tests can be summarized as: (a) mechanical and geometrical characterization of the system's components: evaluation of alignment among radiation source-gantry rotation plan-jaws-MLC-MVCT; (b) treatment beam configuration in static condition: depth dose curves (PDD) and profiles, output factors, output reproducibility and linearity; (c) dynamic component characterization: accuracy and reproducibility of MLC positioning; rotational output reproducibility and linearity, leaf latency, couch movement constancy; (d) gantry-couch and MLC-gantry synchronization; and (e) MVCT image quality. Peculiar periodicity specific tolerance and action levels were defined. Ionization chambers (Exradin A1SL 0.056 cc), films (XOmat-V/EDR2), water and solid water phantoms were used to perform quality assurance measurements. Results: Over a two-year period the final average output variation after possible beam output adjustment was -0.2 ± 1% for the

  20. Effect of CT contrast on volumetric arc therapy planning (RapidArc and helical tomotherapy) for head and neck cancer

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    Liu, Alan J.; Vora, Nayana [Department of Radiation Oncology, City of Hope National Medical Center, Duarte, CA (United States); Suh, Steve [Department of Radiation Physics, City of Hope National Medical Center, Duarte, CA (United States); Liu, An, E-mail: aliu@coh.org [Department of Radiation Physics, City of Hope National Medical Center, Duarte, CA (United States); Schultheiss, Timothy E. [Department of Radiation Physics, City of Hope National Medical Center, Duarte, CA (United States); Wong, Jeffrey Y.C. [Department of Radiation Oncology, City of Hope National Medical Center, Duarte, CA (United States)

    2015-04-01

    The objectives of the study were to evaluate the effect of intravenous contrast in the dosimetry of helical tomotherapy and RapidArc treatment for head and neck cancer and determine if it is acceptable during the computed tomography (CT) simulation to acquire only CT with contrast for treatment planning of head and neck cancer. Overall, 5 patients with head and neck cancer (4 men and 1 woman) treated on helical tomotherapy were analyzed retrospectively. For each patient, 2 consecutive CT scans were performed. The first CT set was scanned before the contrast injection and secondary study set was scanned 45 seconds after contrast. The 2 CTs were autoregistered using the same Digital Imaging and Communications in Medicine coordinates. Tomotherapy and RapidArc plans were generated on 1 CT data set and subsequently copied to the second CT set. Dose calculation was performed, and dose difference was analyzed to evaluate the influence of intravenous contrast media. The dose matrix used for comparison included mean, minimum and maximum doses of planning target volume (PTV), PTV dose coverage, and V{sub 45} {sub Gy}, V{sub 30} {sub Gy}, and V{sub 20} {sub Gy} organ doses. Treatment planning on contrasted images generally showed a lower dose to both organs and target than plans on noncontrasted images. The doses for the points of interest placed in the organs and target rarely changed more than 2% in any patient. In conclusion, treatment planning using a contrasted image had insignificant effect on the dose to the organs and targets. In our opinion, only CT with contrast needs to be acquired during the CT simulation for head and neck cancer. Dose calculations performed on contrasted images can potentially underestimate the delivery dose slightly. However, the errors of planning on a contrasted image should not affect the result in clinically significant way.

  1. Investigation of Pitch and Jaw Width to Decrease Delivery Time of Helical Tomotherapy Treatments for Head and Neck Cancer

    International Nuclear Information System (INIS)

    Moldovan, Monica; Fontenot, Jonas D.; Gibbons, John P.; Lee, Tae Kyu; Rosen, Isaac I.; Fields, Robert S.; Hogstrom, Kenneth R.

    2011-01-01

    Helical tomotherapy plans using a combination of pitch and jaw width settings were developed for 3 patients previously treated for head and neck cancer. Three jaw widths (5, 2.5, and 1 cm) and 4 pitches (0.86, 0.43, 0.287, and 0.215) were used with a (maximum) modulation factor setting of 4. Twelve plans were generated for each patient using an identical optimization procedure (e.g., number of iterations, objective weights, and penalties, etc.), based on recommendations from TomoTherapy (Madison, WI). The plans were compared using isodose plots, dose volume histograms, dose homogeneity indexes, conformity indexes, radiobiological models, and treatment times. Smaller pitches and jaw widths showed better target dose homogeneity and sparing of normal tissue, as expected. However, the treatment time increased inversely proportional to the jaw width, resulting in delivery times of 24 ± 1.9 min for the 1-cm jaw width. Although treatment plans produced with the 2.5-cm jaw were dosimetrically superior to plans produced with the 5-cm jaw, subsequent calculations of tumor control probabilities and normal tissue complication probabilities suggest that these differences may not be radiobiologically meaningful. Because treatment plans produced with the 5-cm jaw can be delivered in approximately half the time of plans produced with the 2.5-cm jaw (5.1 ± 0.6 min vs. 9.5 ± 1.1 min), use of the 5-cm jaw in routine treatment planning may be a viable approach to decreasing treatment delivery times from helical tomotherapy units.

  2. Helical tomotherapy in the treatment of pediatric malignancies: a preliminary report of feasibility and acute toxicity

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    Beltrán César

    2011-08-01

    Full Text Available Abstract Background Radiation therapy plays a central role in the management of many childhood malignancies and Helical Tomotherapy (HT provides potential to decrease toxicity by limiting the radiation dose to normal structures. The aim of this article was to report preliminary results of our clinical experience with HT in pediatric malignancies. Methods In this study 66 consecutive patients younger than 14 years old, treated with HT at our center between January 2006 and April 2010, have been included. We performed statistical analyses to assess the relationship between acute toxicity, graded according to the RTOG criteria, and several clinical and treatment characteristics such as a dose and irradiation volume. Results The median age of patients was 5 years. The most common tumor sites were: central nervous system (57%, abdomen (17% and thorax (6%. The most prevalent histological types were: medulloblastoma (16 patients, neuroblastoma (9 patients and rhabdomyosarcoma (7 patients. A total of 52 patients were treated for primary disease and 14 patients were treated for recurrent tumors. The majority of the patients (72% were previously treated with chemotherapy. The median prescribed dose was 51 Gy (range 10-70 Gy. In 81% of cases grade 1 or 2 acute toxicity was observed. There were 11 cases (16,6% of grade 3 hematological toxicity, two cases of grade 3 skin toxicity and one case of grade 3 emesis. Nine patients (13,6% had grade 4 hematological toxicity. There were no cases of grade 4 non-hematological toxicities. On the univariate analysis, total dose and craniospinal irradiation (24 cases were significantly associated with severe toxicity (grade 3 or more, whereas age and chemotherapy were not. On the multivariate analysis, craniospinal irradiation was the only significant independent risk factor for grade 3-4 toxicity. Conclusion HT in pediatric population is feasible and safe treatment modality. It is characterized by an acceptable level of

  3. Dosimetric Comparison of Helical Tomotherapy and Dynamic Conformal Arc Therapy in Stereotactic Radiosurgery for Vestibular Schwannomas

    International Nuclear Information System (INIS)

    Lee, Tsair-Fwu; Chao, Pei-Ju; Wang, Chang-Yu; Lan, Jen-Hong; Huang, Yu-Je; Hsu, Hsuan-Chih; Sung, Chieh-Cheng; Su, Te-Jen; Lian, Shi-Long; Fang, Fu-Min

    2011-01-01

    The dosimetric results of stereotactic radiosurgery (SRS) for vestibular schwannoma (VS) performed using dynamic conformal arc therapy (DCAT) with the Novalis system and helical TomoTherapy (HT) were compared using plan quality indices. The HT plans were created for 10 consecutive patients with VS previously treated with SRS using the Novalis system. The dosimetric indices used to compare the techniques included the conformity index (CI) and homogeneity index (HI) for the planned target volume (PTV), the comprehensive quality index (CQI) for nine organs at risk (OARs), gradient score index (GSI) for the dose drop-off outside the PTV, and plan quality index (PQI), which was verified using the plan quality discerning power (PQDP) to incorporate 3 plan indices, to evaluate the rival plans. The PTV ranged from 0.27-19.99 cm 3 (median 3.39 cm 3 ), with minimum required PTV prescribed doses of 10-16 Gy (median 12 Gy). Both systems satisfied the minimum required PTV prescription doses. HT conformed better to the PTV (CI: 1.51 ± 0.23 vs. 1.94 ± 0.34; p < 0.01), but had a worse drop-off outside the PTV (GSI: 40.3 ± 10.9 vs. 64.9 ± 13.6; p < 0.01) compared with DCAT. No significant difference in PTV homogeneity was observed (HI: 1.08 ± 0.03 vs. 1.09 ± 0.02; p = 0.20). HT had a significantly lower maximum dose in 4 OARs and significant lower mean dose in 1 OAR; by contrast, DCAT had a significantly lower maximum dose in 1 OAR and significant lower mean dose in 2 OARs, with the CQI of the 9 OARs = 0.92 ± 0.45. Plan analysis using PQI (HT 0.37 ± 0.12 vs. DCAT 0.65 ± 0.08; p < 0.01), and verified using the PQDP, confirmed the dosimetric advantage of HT. However, the HT system had a longer beam-on time (33.2 ± 7.4 vs. 4.6 ± 0.9 min; p < 0.01) and consumed more monitor units (16772 ± 3803 vs. 1776 ± 356.3; p < 0.01). HT had a better dose conformity and similar dose homogeneity but worse dose gradient than DCAT. Plan analysis confirmed the dosimetric advantage of HT

  4. Helical tomotherapy in the treatment of pediatric malignancies: a preliminary report of feasibility and acute toxicity

    International Nuclear Information System (INIS)

    Mesbah, Latifa; Marsiglia, Hugo; Matute, Raúl; Usychkin, Sergey; Marrone, Immacolata; Puebla, Fernando; Mínguez, Cristina; García, Rafael; García, Graciela; Beltrán, César

    2011-01-01

    Radiation therapy plays a central role in the management of many childhood malignancies and Helical Tomotherapy (HT) provides potential to decrease toxicity by limiting the radiation dose to normal structures. The aim of this article was to report preliminary results of our clinical experience with HT in pediatric malignancies. In this study 66 consecutive patients younger than 14 years old, treated with HT at our center between January 2006 and April 2010, have been included. We performed statistical analyses to assess the relationship between acute toxicity, graded according to the RTOG criteria, and several clinical and treatment characteristics such as a dose and irradiation volume. The median age of patients was 5 years. The most common tumor sites were: central nervous system (57%), abdomen (17%) and thorax (6%). The most prevalent histological types were: medulloblastoma (16 patients), neuroblastoma (9 patients) and rhabdomyosarcoma (7 patients). A total of 52 patients were treated for primary disease and 14 patients were treated for recurrent tumors. The majority of the patients (72%) were previously treated with chemotherapy. The median prescribed dose was 51 Gy (range 10-70 Gy). In 81% of cases grade 1 or 2 acute toxicity was observed. There were 11 cases (16,6%) of grade 3 hematological toxicity, two cases of grade 3 skin toxicity and one case of grade 3 emesis. Nine patients (13,6%) had grade 4 hematological toxicity. There were no cases of grade 4 non-hematological toxicities. On the univariate analysis, total dose and craniospinal irradiation (24 cases) were significantly associated with severe toxicity (grade 3 or more), whereas age and chemotherapy were not. On the multivariate analysis, craniospinal irradiation was the only significant independent risk factor for grade 3-4 toxicity. HT in pediatric population is feasible and safe treatment modality. It is characterized by an acceptable level of acute toxicity that we have seen in this highly

  5. A technique for adaptive image-guided helical tomotherapy for lung cancer

    International Nuclear Information System (INIS)

    Ramsey, Chester R.; Langen, Katja M.; Kupelian, Patrick A.; Scaperoth, Daniel D.; Meeks, Sanford L.; Mahan, Stephen L.; Seibert, Rebecca M.

    2006-01-01

    Purpose: The gross tumor volume (GTV) for many lung cancer patients can decrease during the course of radiation therapy. As the tumor reduces in size during treatment, the margin added around the GTV effectively becomes larger, which can result in the excessive irradiation of normal lung tissue. The specific goal of this study is to evaluate the feasibility of using image-guided adaptive radiation therapy to adjust the planning target volume weekly based on the previous week's CT image sets that were used for image-guided patient setup. Methods and Materials: Megavoltage computed tomography (MVCT) images of the GTV were acquired daily on a helical tomotherapy system. These images were used to position the patient and to measure reduction in GTV volume. A planning study was conducted to determine the amount of lung-sparing that could have been achieved if adaptive therapy had been used. Treatment plans were created in which the target volumes were reduced after tumor reduction was measured. Results: A total of 158 MVCT imaging sessions were performed on 7 lung patients. The GTV was reduced by 60-80% during the course of treatment. The tumor reduction in the first 60 days of treatment can be modeled using the second-order polynomial R 0.0002t 2 - 0.0219t + 1.0, where R is the percent reduction in GTV, and t is the number of elapsed days. Based on these treatment planning studies, the absolute volume of ipsilateral lung receiving 20 Gy can be reduced between 17% and 23% (21% mean) by adapting the treatment delivery. The benefits of adaptive therapy are the greatest for tumor volumes ≥25 cm 3 and are directly dependent on GTV reduction during treatment. Conclusions: Megavoltage CT-based image guidance can be used to position lung cancer patients daily. This has the potential to decrease margins associated with daily setup error. Furthermore, the adaptive therapy technique described in this article can decrease the volume of healthy lung tissue receiving above 20 Gy

  6. Measurement of MV CT dose index for Hi-ART helical tomotherapy unit

    International Nuclear Information System (INIS)

    Wang Yunlai; Liao Xiongfei

    2010-01-01

    Objective: To evaluate the patient dose from Hi-ART MV helical CT imaging in image-guided radiotherapy. Methods: Weighted CT dose index (CTDI W ) was measured with PTW TM30009 CT ion chamber in head and body phantoms, respectively,for slice thicknesses of 2, 4, 6 mm with scanned range of 5 cm and 15 cm. Dose length products (DLP) were subsequently calculated. The CTDI W and DLP were compared with XVI kV CBCT and ACQSim simulator CT for routine clinical protocols. Results: An inverse relationship between CTDI and the slice thickness was found. The dose distribution was inhomogeneous owing to the attenuation of the couch. CTDI and DLP had close relationship with the slice thickness and the scanned range. Patient dose from MVCT was lower than XVI CBCT for head, but larger for body scan. Conclusions: CTDI W can be used to assess the patient dose in MV helical CT due to its simplicity for measurement and reproducibility. Regular measurement should be performed in QA and QC program. Appropriate slice thickness and scan range should be chosen to reduce the patient dose. (authors)

  7. Monte Carlo simulations of patient dose perturbations in rotational-type radiotherapy due to a transverse magnetic field: A tomotherapy investigation

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Y. M.; Geurts, M.; Smilowitz, J. B.; Bednarz, B. P., E-mail: bbednarz2@wisc.edu [Department of Medical Physics, Wisconsin Institutes for Medical Research, University of Wisconsin, Madison, Wisconsin 53703 (United States); Sterpin, E. [Molecular Imaging, Radiotherapy and Oncology, Université catholique de Louvain, Brussels, Belgium 1348 (Belgium)

    2015-02-15

    Purpose: Several groups are exploring the integration of magnetic resonance (MR) image guidance with radiotherapy to reduce tumor position uncertainty during photon radiotherapy. The therapeutic gain from reducing tumor position uncertainty using intrafraction MR imaging during radiotherapy could be partially offset if the negative effects of magnetic field-induced dose perturbations are not appreciated or accounted for. The authors hypothesize that a more rotationally symmetric modality such as helical tomotherapy will permit a systematic mediation of these dose perturbations. This investigation offers a unique look at the dose perturbations due to homogeneous transverse magnetic field during the delivery of Tomotherapy{sup ®} Treatment System plans under varying degrees of rotational beamlet symmetry. Methods: The authors accurately reproduced treatment plan beamlet and patient configurations using the Monte Carlo code GEANT4. This code has a thoroughly benchmarked electromagnetic particle transport physics package well-suited for the radiotherapy energy regime. The three approved clinical treatment plans for this study were for a prostate, head and neck, and lung treatment. The dose heterogeneity index metric was used to quantify the effect of the dose perturbations to the target volumes. Results: The authors demonstrate the ability to reproduce the clinical dose–volume histograms (DVH) to within 4% dose agreement at each DVH point for the target volumes and most planning structures, and therefore, are able to confidently examine the effects of transverse magnetic fields on the plans. The authors investigated field strengths of 0.35, 0.7, 1, 1.5, and 3 T. Changes to the dose heterogeneity index of 0.1% were seen in the prostate and head and neck case, reflecting negligible dose perturbations to the target volumes, a change from 5.5% to 20.1% was observed with the lung case. Conclusions: This study demonstrated that the effect of external magnetic fields can

  8. SU-F-T-267: A Clarkson-Based Independent Dose Verification for the Helical Tomotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Nagata, H [Shonan Kamakura General Hospital, Kamakura, Kanagawa, (Japan); Juntendo University, Hongo, Tokyo (Japan); Hongo, H [Shonan Kamakura General Hospital, Kamakura, Kanagawa, (Japan); Tsukuba University, Tsukuba, Ibaraki (Japan); Kawai, D [Kanagawa Cancer Center, Yokohama, Kanagawa (Japan); Takahashi, R [Cancer Institute Hospital of Japanese Foundation for Cancer Research, Koto, Tokyo (Japan); Hashimoto, H [Shonan Fujisawa Tokushukai Hospital, Fujisawa, Kanagawa (Japan); Tachibana, H [National Cancer Center, Kashiwa, Chiba (Japan)

    2016-06-15

    Purpose: There have been few reports for independent dose verification for Tomotherapy. We evaluated the accuracy and the effectiveness of an independent dose verification system for the Tomotherapy. Methods: Simple MU Analysis (SMU, Triangle Product, Ishikawa, Japan) was used as the independent verification system and the system implemented a Clarkson-based dose calculation algorithm using CT image dataset. For dose calculation in the SMU, the Tomotherapy machine-specific dosimetric parameters (TMR, Scp, OAR and MLC transmission factor) were registered as the machine beam data. Dose calculation was performed after Tomotherapy sinogram from DICOM-RT plan information was converted to the information for MU and MLC location at more segmented control points. The performance of the SMU was assessed by a point dose measurement in non-IMRT and IMRT plans (simple target and mock prostate plans). Subsequently, 30 patients’ treatment plans for prostate were compared. Results: From the comparison, dose differences between the SMU and the measurement were within 3% for all cases in non-IMRT plans. In the IMRT plan for the simple target, the differences (Average±1SD) were −0.70±1.10% (SMU vs. TPS), −0.40±0.10% (measurement vs. TPS) and −1.20±1.00% (measurement vs. SMU), respectively. For the mock prostate, the differences were −0.40±0.60% (SMU vs. TPS), −0.50±0.90% (measurement vs. TPS) and −0.90±0.60% (measurement vs. SMU), respectively. For patients’ plans, the difference was −0.50±2.10% (SMU vs. TPS). Conclusion: A Clarkson-based independent dose verification for the Tomotherapy can be clinically available as a secondary check with the similar tolerance level of AAPM Task group 114. This research is partially supported by Japan Agency for Medical Research and Development (AMED)

  9. Helical tomotherapy for SIB and hypo-fractionated treatments in lung carcinomas: A 4D Monte Carlo treatment planning study

    International Nuclear Information System (INIS)

    Sterpin, Edmond; Janssens, Guillaume; Orban de Xivry, Jonathan; Goossens, Samuel; Wanet, Marie; Lee, John A.; Delor, Antoine; Bol, Vanesa; Vynckier, Stefaan; Gregoire, Vincent; Geets, Xavier

    2012-01-01

    Purpose: To evaluate the impact of intra-fraction motion induced by regular breathing on treatment quality for helical tomotherapy treatments. Material and methods: Four patients treated by simultaneous-integrated boost (SIB) and three by hypo-fractionated stereotactic treatments (hypo-fractionated, 18 Gy/fraction) were included. All patients were coached to ensure regular breathing. For the SIB group, the tumor volume was delineated using CT information only (CTV CT ) and the boost region was based on PET information (GTV PET , no CTV extension). In the hypo-fractionated group, a GTV based on CT information was contoured. In both groups, ITVs were defined according to 4D data. The PTV included the ITV plus a setup error margin. The treatment was planned using the tomotherapy TPS on 3D CT images. In order to verify the impact of intra-fraction motion and interplay effects, dose calculations were performed using a previously validated Monte Carlo model of tomotherapy (TomoPen): first on the planning 3D CT (“planned dose”) and second, on the 10 phases of the 4D scan. For the latter, two dose distributions, termed “interplay simulated” or “no interplay” were computed with and without beamlet-phase correlation over the 10 phases and combined using deformable dose registration. Results: In all cases, DVHs of “interplay simulated” dose distributions complied within 1% of the original clinical objectives used for planning, defined according to ICRU (report 83) and RTOG (trials 0236 and 0618) recommendations, for SIB and hypo-fractionated groups, respectively. For one patient in the hypo-fractionated group, D mean to the CTV CT was 2.6% and 2.5% higher than “planned” for “interplay simulated” and “no interplay”, respectively. Conclusion: For the patients included in this study, assuming regular breathing, the results showed that interplay of breathing and tomotherapy delivery motions did not affect significantly plan delivery accuracy. Hence

  10. Investigating output and energy variations and their relationship to delivery QA results using Statistical Process Control for helical tomotherapy.

    Science.gov (United States)

    Binny, Diana; Mezzenga, Emilio; Lancaster, Craig M; Trapp, Jamie V; Kairn, Tanya; Crowe, Scott B

    2017-06-01

    The aims of this study were to investigate machine beam parameters using the TomoTherapy quality assurance (TQA) tool, establish a correlation to patient delivery quality assurance results and to evaluate the relationship between energy variations detected using different TQA modules. TQA daily measurement results from two treatment machines for periods of up to 4years were acquired. Analyses of beam quality, helical and static output variations were made. Variations from planned dose were also analysed using Statistical Process Control (SPC) technique and their relationship to output trends were studied. Energy variations appeared to be one of the contributing factors to delivery output dose seen in the analysis. Ion chamber measurements were reliable indicators of energy and output variations and were linear with patient dose verifications. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  11. Sparing of the hippocampus and limbic circuit during whole brain radiation therapy: a dosimetric study using helical tomotherapy

    International Nuclear Information System (INIS)

    Marsh, J.C.; Gielda, B.T.; Herskovic, A.M.; Turian, J.V.

    2010-01-01

    Full text: The study aims to assess the feasibility of dosimetrically sparing the limbic circuit during whole brain radiation therapy (WBRT) and prophylactic cranial irradiation (PCI). Methods and Materials: We contoured the brain/brainstem on fused MRI and CT as the target volume (PTV) in 11 patients, excluding the hippocampus and the rest of the limbic circuit, which were considered organs at risk (OARs). PCI and WBRT helical tomotherapy plans were prepared for each patient with a 1.0-cm field width, pitch 0.285, initial modulation factor = 2.5. We attempted to spare the hippocampus and the rest of the limbic circuit while treating the rest of the brain to 30 Gy in 15 fractions (PCI) or 35 Gy in 14 fractions (WBRT) with VlOO ∼ 95%. The quality of the plans was assessed by calculating mean dose and equivalent uniform dose (EUD) for OARs and the % volume of the PTV receiving the prescribed dose, V 100. Results: In the PCI plans, mean doses/EUD were: hippocampus 12.5 Gy/ 14.23 Gy, rest of limbic circuit 17.0 Gy/19.02 Gy. In the WBRT plans, mean doses/EUD were: hippocampus 14.3 Gy/16.07 Gy, rest of limbic circuit 17.9 Gy/20.74 Gy. The mean VlOO for the rest of the brain (PTV) were 94.7% (PCl) and 95.1 % (WBRT). Mean PCI and WBRT treatment times were essentially identical (mean 15.23 min, range 14.27-17.5). Conclusions: It is dosimetrically feasible to spare the hippocampus and the rest of the limbic circuit using helical tomotherapy while treating the rest of the brain to full dose.

  12. Accelerated partial breast irradiation using robotic radiotherapy: a dosimetric comparison with tomotherapy and three-dimensional conformal radiotherapy.

    Science.gov (United States)

    Rault, Erwann; Lacornerie, Thomas; Dang, Hong-Phuong; Crop, Frederik; Lartigau, Eric; Reynaert, Nick; Pasquier, David

    2016-02-27

    Accelerated partial breast irradiation (APBI) is a new breast treatment modality aiming to reduce treatment time using hypo fractionation. Compared to conventional whole breast irradiation that takes 5 to 6 weeks, APBI is reported to induce worse cosmetic outcomes both when using three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT). These late normal tissue effects may be attributed to the dose volume effect because a large portion of the non-target breast tissue volume (NTBTV) receives a high dose. In the context of APBI, non-coplanar beams could spare the NTBTV more efficiently. This study evaluates the dosimetric benefit of using the Cyberknife (CK) for APBI in comparison to IMRT (Tomotherapy) and three dimensional conformal radiotherapy (3D-CRT). The possibility of using surgical clips, implanted during surgery, to track target movements is investigated first. A phantom of a female thorax was designed in-house using the measurements of 20 patients. Surgical clips of different sizes were inserted inside the breast. A treatment plan was delivered to the mobile and immobile phantom. The motion compensation accuracy was evaluated using three radiochromic films inserted inside the breast. Three dimensional conformal radiotherapy (3D-CRT), Tomotherapy (TOMO) and CK treatment plans were calculated for 10 consecutive patients who received APBI in Lille. To ensure a fair comparison of the three techniques, margins applied to the CTV were set to 10 mm. However, a second CK plan was prepared using 3 mm margins to evaluate the benefits of motion compensation. Only the larger clips (VITALITEC Medium-Large) could be tracked inside the larger breast (all gamma indices below 1 for 1 % of the maximum dose and 1 mm). All techniques meet the guidelines defined in the NSABP/RTOG and SHARE protocols. As the applied dose volume constraints are very strong, insignificant dosimetric differences exist between techniques regarding the PTV

  13. Accelerated partial breast irradiation using robotic radiotherapy: a dosimetric comparison with tomotherapy and three-dimensional conformal radiotherapy

    International Nuclear Information System (INIS)

    Rault, Erwann; Lacornerie, Thomas; Dang, Hong-Phuong; Crop, Frederik; Lartigau, Eric; Reynaert, Nick; Pasquier, David

    2016-01-01

    Accelerated partial breast irradiation (APBI) is a new breast treatment modality aiming to reduce treatment time using hypo fractionation. Compared to conventional whole breast irradiation that takes 5 to 6 weeks, APBI is reported to induce worse cosmetic outcomes both when using three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT). These late normal tissue effects may be attributed to the dose volume effect because a large portion of the non-target breast tissue volume (NTBTV) receives a high dose. In the context of APBI, non-coplanar beams could spare the NTBTV more efficiently. This study evaluates the dosimetric benefit of using the Cyberknife (CK) for APBI in comparison to IMRT (Tomotherapy) and three dimensional conformal radiotherapy (3D-CRT). The possibility of using surgical clips, implanted during surgery, to track target movements is investigated first. A phantom of a female thorax was designed in-house using the measurements of 20 patients. Surgical clips of different sizes were inserted inside the breast. A treatment plan was delivered to the mobile and immobile phantom. The motion compensation accuracy was evaluated using three radiochromic films inserted inside the breast. Three dimensional conformal radiotherapy (3D-CRT), Tomotherapy (TOMO) and CK treatment plans were calculated for 10 consecutive patients who received APBI in Lille. To ensure a fair comparison of the three techniques, margins applied to the CTV were set to 10 mm. However, a second CK plan was prepared using 3 mm margins to evaluate the benefits of motion compensation. Only the larger clips (VITALITEC Medium-Large) could be tracked inside the larger breast (all gamma indices below 1 for 1 % of the maximum dose and 1 mm). All techniques meet the guidelines defined in the NSABP/RTOG and SHARE protocols. As the applied dose volume constraints are very strong, insignificant dosimetric differences exist between techniques regarding the PTV

  14. Hypofractionated radiotherapy for primary or secondary oligometastatic lung cancer using Tomotherapy

    International Nuclear Information System (INIS)

    Chang, Heng-Jui; Ko, Hui-Ling; Lee, Cheng-Yen; Wu, Ren-Hong; Yeh, Yu-Wung; Jiang, Jiunn-Song; Kao, Shang-Jyh; Chi, Kwan-Hwa

    2012-01-01

    To retrospectively review the outcome of patients with primary or secondary oligometastatic lung cancer, treated with hypofractionated Tomotherapy. Between April 2007 and June 2011, a total of 33 patients with oligometastatic intrapulmonary lesions underwent hypofractionated radiotherapy by Tomotherapy along with appropriate systemic therapy. There were 24 primary, and 9 secondary lung cancer cases. The radiation doses ranged from 4.5 to 7.0 Gy per fraction, multiplied by 8–16 fractions. The median dose per fraction was 4.5 Gy (range, 4.5-7.0 Gy), and the median total dose was 49.5 Gy (range, 45–72 Gy). The median estimated biological effective dose at 10 Gy (BED 10 ) was 71.8 Gy (range, 65.3–119.0 Gy), and that at 3 Gy (BED 3 ) was 123.8 Gy (range, 112.5–233.3 Gy). The mean lung dose (MLD) was constrained mainly under 1200 cGy. The median gross tumor volume (GTV) was 27.9 cm 3 (range: 2.5–178.1 cm 3 ). The median follow-up period was 25.8 months (range, 3.0–60.7 months). The median overall survival (OS) time was 32.1 months for the 24 primary lung cancer patients, and >40 months for the 9 metastatic lung patients. The median survival time of the patients with extra-pulmonary disease (EPD) was 11.2 months versus >50 months (not reached) in the patients without EPD (p < 0.001). Those patients with smaller GTV (≦27.9 cm 3 ) had a better survival than those with larger GTV (>27.9 cm 3 ): >40 months versus 12.85 months (p = 0.047). The patients with ≦2 lesions had a median survival >40 months, whereas those with ≧3 lesions had 26 months (p = 0.065). The 2-year local control (LC) rate was 94.7%. Only 2 patients (6.1%) developed ≧grade 3 radiation pneumonitis. Using Tomotherapy in hypofractionation may be effective for selected primary or secondary lung oligometastatic diseases, without causing significant toxicities. Pulmonary oligometastasis patients without EPD had better survival outcomes than those with EPD. Moreover, GTV is more significant than

  15. Hypofractionated radiotherapy for primary or secondary oligometastatic lung cancer using Tomotherapy

    Science.gov (United States)

    2012-01-01

    Background To retrospectively review the outcome of patients with primary or secondary oligometastatic lung cancer, treated with hypofractionated Tomotherapy. Methods Between April 2007 and June 2011, a total of 33 patients with oligometastatic intrapulmonary lesions underwent hypofractionated radiotherapy by Tomotherapy along with appropriate systemic therapy. There were 24 primary, and 9 secondary lung cancer cases. The radiation doses ranged from 4.5 to 7.0 Gy per fraction, multiplied by 8–16 fractions. The median dose per fraction was 4.5 Gy (range, 4.5-7.0 Gy), and the median total dose was 49.5 Gy (range, 45–72 Gy). The median estimated biological effective dose at 10 Gy (BED10) was 71.8 Gy (range, 65.3–119.0 Gy), and that at 3 Gy (BED3) was 123.8 Gy (range, 112.5–233.3 Gy). The mean lung dose (MLD) was constrained mainly under 1200 cGy. The median gross tumor volume (GTV) was 27.9 cm3 (range: 2.5–178.1 cm3). Results The median follow-up period was 25.8 months (range, 3.0–60.7 months). The median overall survival (OS) time was 32.1 months for the 24 primary lung cancer patients, and >40 months for the 9 metastatic lung patients. The median survival time of the patients with extra-pulmonary disease (EPD) was 11.2 months versus >50 months (not reached) in the patients without EPD (p 27.9 cm3): >40 months versus 12.85 months (p = 0.047). The patients with ≦2 lesions had a median survival >40 months, whereas those with ≧3 lesions had 26 months (p = 0.065). The 2-year local control (LC) rate was 94.7%. Only 2 patients (6.1%) developed ≧grade 3 radiation pneumonitis. Conclusion Using Tomotherapy in hypofractionation may be effective for selected primary or secondary lung oligometastatic diseases, without causing significant toxicities. Pulmonary oligometastasis patients without EPD had better survival outcomes than those with EPD. Moreover, GTV is more significant than lesion number in

  16. Hypofractionated radiotherapy for primary or secondary oligometastatic lung cancer using Tomotherapy

    Directory of Open Access Journals (Sweden)

    Chang Heng-Jui

    2012-12-01

    Full Text Available Abstract Background To retrospectively review the outcome of patients with primary or secondary oligometastatic lung cancer, treated with hypofractionated Tomotherapy. Methods Between April 2007 and June 2011, a total of 33 patients with oligometastatic intrapulmonary lesions underwent hypofractionated radiotherapy by Tomotherapy along with appropriate systemic therapy. There were 24 primary, and 9 secondary lung cancer cases. The radiation doses ranged from 4.5 to 7.0 Gy per fraction, multiplied by 8–16 fractions. The median dose per fraction was 4.5 Gy (range, 4.5-7.0 Gy, and the median total dose was 49.5 Gy (range, 45–72 Gy. The median estimated biological effective dose at 10 Gy (BED10 was 71.8 Gy (range, 65.3–119.0 Gy, and that at 3 Gy (BED3 was 123.8 Gy (range, 112.5–233.3 Gy. The mean lung dose (MLD was constrained mainly under 1200 cGy. The median gross tumor volume (GTV was 27.9 cm3 (range: 2.5–178.1 cm3. Results The median follow-up period was 25.8 months (range, 3.0–60.7 months. The median overall survival (OS time was 32.1 months for the 24 primary lung cancer patients, and >40 months for the 9 metastatic lung patients. The median survival time of the patients with extra-pulmonary disease (EPD was 11.2 months versus >50 months (not reached in the patients without EPD (p 3 had a better survival than those with larger GTV (>27.9 cm3: >40 months versus 12.85 months (p = 0.047. The patients with ≦2 lesions had a median survival >40 months, whereas those with ≧3 lesions had 26 months (p = 0.065. The 2-year local control (LC rate was 94.7%. Only 2 patients (6.1% developed ≧grade 3 radiation pneumonitis. Conclusion Using Tomotherapy in hypofractionation may be effective for selected primary or secondary lung oligometastatic diseases, without causing significant toxicities. Pulmonary oligometastasis patients without EPD had better survival outcomes than those with

  17. Helical tomotherapy in patients with breast cancer and complex treatment volumes.

    Science.gov (United States)

    Cendales, Ricardo; Schiappacasse, Luis; Schnitman, Franco; García, Graciela; Marsiglia, Hugo

    2011-04-01

    To describe early clinical results of tomotherapy treatment in patients with breast cancer and complex treatment volumes. Ten patients were treated with tomotherapy between January 2009 and March 2010. Treatment planning objectives were to cover at least 95% of the planning target volume with the 95% isodose; to have a minimum dose of 90% and a maximum dose of 105%. All treatments included daily CT/megavoltage image guidance. Acute toxicity was recorded weekly. Six patients were treated because constraints were not accomplished for heart, lung or contralateral breast in a previous three-dimensional conformal plan; two for preexisting cardiac or pulmonary disease, and two more for bilateral breast irradiation. Treatment volumes included the whole breast in the majority of patients, as well as the supraclavicular and the internal mammary chain nodes when indicated. Most patients were older than 50 years, and had an early breast cancer, with positive oestrogen receptors, negative HER2 expression and a poorly differentiated, infiltrating ductal carcinoma. The majority of patients had received neoadjuvant chemotherapy associated to breast-conserving surgery and adjuvant hormonotherapy. Median homogeneity index was 1.09; median coverage index was 0.81. Median V20Gy and V10Gy for ipsilateral lung was 20% and 37.1% respectively. Median V25 and V35 for heart was 15% and 4% respectively. Median dose for contralateral breast was 7 Gy. Skin acute toxicity was grade 1 in 41.7% and grade 2 in 58.3%. Tomotherapy is a technique capable of delivering a well tolerated treatment with high homogeneity and coverage indexes and high capabilities for sparing the organs at risk in patients with anatomically complex breast cancer, bilateral breast cancer, indication for internal mammary chain node irradiation, cardiac toxicity derived from chemotherapy, or preexisting cardiac or pulmonary disease. Further studies are required to evaluate local control and late toxicity.

  18. Helical Tomotherapy Versus Single-Arc Intensity-Modulated Arc Therapy: A Collaborative Dosimetric Comparison Between Two Institutions

    International Nuclear Information System (INIS)

    Rong Yi; Tang, Grace; Welsh, James S.; Mohiuddin, Majid M.; Paliwal, Bhudatt; Yu, Cedric X.

    2011-01-01

    Purpose: Both helical tomotherapy (HT) and single-arc intensity-modulated arc therapy (IMAT) deliver radiation using rotational beams with multileaf collimators. We report a dual-institution study comparing dosimetric aspects of these two modalities. Methods and Materials: Eight patients each were selected from the University of Maryland (UMM) and the University of Wisconsin Cancer Center Riverview (UWR), for a total of 16 cases. Four cancer sites including brain, head and neck (HN), lung, and prostate were selected. Single-arc IMAT plans were generated at UMM using Varian RapidArc (RA), and HT plans were generated at UWR using Hi-Art II TomoTherapy. All 16 cases were planned based on the identical anatomic contours, prescriptions, and planning objectives. All plans were swapped for analysis at the same time after final approval. Dose indices for targets and critical organs were compared based on dose-volume histograms, the beam-on time, monitor units, and estimated leakage dose. After the disclosure of comparison results, replanning was done for both techniques to minimize diversity in optimization focus from different operators. Results: For the 16 cases compared, the average beam-on time was 1.4 minutes for RA and 4.8 minutes for HT plans. HT provided better target dose homogeneity (7.6% for RA and 4.2% for HT) with a lower maximum dose (110% for RA and 105% for HT). Dose conformation numbers were comparable, with RA being superior to HT (0.67 vs. 0.60). The doses to normal tissues using these two techniques were comparable, with HT showing lower doses for more critical structures. After planning comparison results were exchanged, both techniques demonstrated improvements in dose distributions or treatment delivery times. Conclusions: Both techniques created highly conformal plans that met or exceeded the planning goals. The delivery time and total monitor units were lower in RA than in HT plans, whereas HT provided higher target dose uniformity.

  19. Utility of Megavoltage Fan-Beam CT for Treatment Planning in a Head-And-Neck Cancer Patient with Extensive Dental Fillings Undergoing Helical Tomotherapy

    International Nuclear Information System (INIS)

    Yang, Claus; Liu Tianxiao; Jennelle, Richard L.; Ryu, Janice K.; Vijayakumar, Srinivasan; Purdy, James A.; Chen, Allen M.

    2010-01-01

    The purpose of this study was to demonstrate the potential utility of megavoltage fan-beam computed tomography (MV-FBCT) for treatment planning in a patient undergoing helical tomotherapy for nasopharyngeal carcinoma in the presence of extensive dental artifact. A 28-year-old female with locally advanced nasopharyngeal carcinoma presented for radiation therapy. Due to the extensiveness of the dental artifact present in the oral cavity kV-CT scan acquired at simulation, which made treatment planning impossible on tomotherapy planning system, MV-FBCT imaging was obtained using the HI-ART tomotherapy treatment machine, with the patient in the treatment position, and this information was registered with her original kV-CT scan for the purposes of structure delineation, dose calculation, and treatment planning. To validate the feasibility of the MV-FBCT-generated treatment plan, an electron density CT phantom (model 465, Gammex Inc., Middleton, WI) was scanned using MV-FBCT to obtain CT number to density table. Additionally, both a 'cheese' phantom (which came with the tomotherapy treatment machine) with 2 inserted ion chambers and a generic phantom called Quasar phantom (Modus Medical Devices Inc., London, ON, Canada) with one inserted chamber were used to confirm dosimetric accuracy. The MV-FBCT could be used to clearly visualize anatomy in the region of the dental artifact and provide sufficient soft-tissue contrast to assist in the delineation of normal tissue structures and fat planes. With the elimination of the dental artifact, the MV-FBCT images allowed more accurate dose calculation by the tomotherapy system. It was confirmed that the phantom material density was determined correctly by the tomotherapy MV-FBCT number to density table. The ion chamber measurements agreed with the calculations from the MV-FBCT generated phantom plan within 2%. MV-FBCT may be useful in radiation treatment planning for nasopharyngeal cancer patients in the setting of extensive

  20. Conversion of helical tomotherapy plans to step-and-shoot IMRT plans--Pareto front evaluation of plans from a new treatment planning system.

    Science.gov (United States)

    Petersson, Kristoffer; Ceberg, Crister; Engström, Per; Benedek, Hunor; Nilsson, Per; Knöös, Tommy

    2011-06-01

    The resulting plans from a new type of treatment planning system called SharePlan have been studied. This software allows for the conversion of treatment plans generated in a TomoTherapy system for helical delivery, into plans deliverable on C-arm linear accelerators (linacs), which is of particular interest for clinics with a single TomoTherapy unit. The purpose of this work was to evaluate and compare the plans generated in the SharePlan system with the original TomoTherapy plans and with plans produced in our clinical treatment planning system for intensity-modulated radiation therapy (IMRT) on C-arm linacs. In addition, we have analyzed how the agreement between SharePlan and TomoTherapy plans depends on the number of beams and the total number of segments used in the optimization. Optimized plans were generated for three prostate and three head-and-neck (H&N) cases in the TomoTherapy system, and in our clinical treatment planning systems (TPS) used for IMRT planning with step-and-shoot delivery. The TomoTherapy plans were converted into step-and-shoot IMRT plans in SharePlan. For each case, a large number of Pareto optimal plans were created to compare plans generated in SharePlan with plans generated in the Tomotherapy system and in the clinical TPS. In addition, plans were generated in SharePlan for the three head-and-neck cases to evaluate how the plan quality varied with the number of beams used. Plans were also generated with different number of beams and segments for other patient cases. This allowed for an evaluation of how to minimize the number of required segments in the converted IMRT plans without compromising the agreement between them and the original TomoTherapy plans. The plans made in SharePlan were as good as or better than plans from our clinical system, but they were not as good as the original TomoTherapy plans. This was true for both the head-and-neck and the prostate cases, although the differences between the plans for the latter were

  1. Advances in the implementation of helical tomotherapy-based total marrow irradiation with a novel field junction technique

    Energy Technology Data Exchange (ETDEWEB)

    Zeverino, Michele, E-mail: michele.zeverino@istge.it [Medical Physics Department, IRCCS, Istituto Nazionale per la Ricerca sul cancro, Genoa (Italy); Agostinelli, Stefano; Taccini, Gianni; Cavagnetto, Francesca; Garelli, Stefania; Gusinu, Marco [Medical Physics Department, IRCCS, Istituto Nazionale per la Ricerca sul cancro, Genoa (Italy); Vagge, Stefano; Barra, Salvina; Corvo, Renzo [Radiation Oncology Department, IRCCS, Istituto Nazionale per la Ricerca sul cancro, Genoa (Italy)

    2012-10-01

    Given the limitations in the travel ability of the helical tomotherapy (HT) couch, total marrow irradiation (TMI) has to be split in 2 segments, with the lower limbs treated with feet first orientation. The aim of this work is to present a planning technique useful to reduce the dose inhomogeneity resulting from the matching of the 2 helical dose distributions. Three HT plans were generated for each of the 18 patients enrolled. Upper TMI (UTMI) and lower TMI (LTMI) were planned onto the whole-body computed tomography (CT) and on the lower-limb CT, respectively. A twin lower TMI plan (tLTMI) was designed on the whole-body CT. Agreement between LTMI and tLTMI plans was assessed by computing for each dose-volume histogram (DVH) structure the {gamma} index scored with 1% of dose and volume difference thresholds. UTMI and tLTMI plans were summed together on the whole-body CT, enabling the evaluation of dose inhomogeneity. Moreover, a couple of transition volumes were used to improve the dose uniformity in the abutment region. For every DVH, a number of points >99% passed the {gamma} analysis, validating the method used to generate the twin plan. The planned dose inhomogeneity at the junction level resulted within {+-}10% of the prescribed dose. Median dose reduction to organs at risk ranged from 30-80% of the prescribed dose. Mean conformity index was 1.41 (range 1.36-1.44) for the whole-body target. The technique provided a 'full helical' dose distribution for TMI treatments, which can be considered effective only if the dose agreement between LTMI and tLTMI plans is met. The planning of TMI with HT for the whole body with adequate dose homogeneity and conformity was shown to be feasible.

  2. Evidence of Limited Motion of the Prostate by Carefully Emptying the Rectum as Assessed by Daily MVCT Image Guidance with Helical Tomotherapy

    International Nuclear Information System (INIS)

    Fiorino, Claudio Ph.D.; Di Muzio, Nadia; Broggi, Sara; Cozzarini, Cesare; Maggiulli, Eleonora M.Sc.; Alongi, Filippo; Valdagni, Riccardo; Fazio, Ferruccio; Calandrino, Riccardo

    2008-01-01

    Purpose: To assess setup and organ motion error by means of analysis of daily megavoltage computed tomography (MVCT) of patients treated with hypofractionated helical tomotherapy (71.4-74.2 Gy in 28 fractions). Methods and Materials: Data from 21 patients were analyzed. Patients were instructed to empty the rectum carefully before planning CT and every morning before therapy by means of a self-applied rectal enema. The position of the prostate was assessed by means of automatic bone matching (BM) with the planning kilovoltage CT (BM, setup error) followed by a direct visualization (DV) match on the prostate. Deviations between planning and therapy positions referred to BM and BM + DV were registered for the three main axes. In case of a full rectum at MVCT with evident shift of the prostate, treatment was postponed until after additional rectal emptying procedures; in this case, additional MVCT was performed before delivering the treatment. Data for 522 fractions were available; the impact of post-MVCT procedure was investigated for 17 of 21 patients (410 fractions). Results: Prostate motion relative to bony anatomy was limited. Concerning posterior-anterior shifts, only 4.9% and 2.7% of fractions showed deviation of 3 mm or greater of the prostate relative to BM without and with consideration of post-MVCT procedures, respectively. Interobserver variability for BM + DV match was within 0.8 mm (1 SD). Conclusions: Daily MVCT-based correction is feasible. The BM + DV matching was found to be consistent between operators. Rectal emptying using a daily enema is an efficient tool to minimize prostate motion, even for centers that have not yet implemented image-guided radiotherapy

  3. Measurement of dosimetric parameters for Hi-ART helical tomotherapy unit

    International Nuclear Information System (INIS)

    Wang Yunlai; Sha Xiangyou; Dai Xiangkun; Ma Lin; Feng Linchun; Qu Baolin

    2008-01-01

    Objective: To develop a measurement method of dosimetric parameters for Hi-ART tomotherapy unit. Methods: Percentage depth doses and beam profiles were measured using the dedicated mini water phantom, and compared to the results of 6 MV X-ray from Primus accelerator. Following the AAPM TG51 protocol, absolute dose calibration was carried out under SSD of 8.5 cm at depth of 1.5 cm for field of 5 cm x 40 cm. The output linearity and reproducibility were evaluated. The output variation with the gantry rotation was also investigated using 0.6 cm 3 ion chamber in cylindrical perplex phantom and on-board MVCT detectors. Leaf fluence output factors were quantified for the leaf of interest and its adjacent leaves. Results: The buildup depth was around 1.0 cm. The PDD values at 10 cm for Hi-ART and Primus were 59.7% and 64.7%, respectively. Varying with the field width, the lateral and longitudinal beam profiles were not so homogeneous as the Primus fields. The measured dose rate was 848.38 cGy/min. The fitted linear function between the readings of dosimeter and the irradiated time was R(nC) =-0.017 + 0.256· t(sec), with a relative coefficient of 0.999. The maximum deviation and standard deviation of output were 1.6% and less than 0.5%; The maximum deviation and standard deviation of output changed by gantry angle were 1.1% and 0.5%, respectively. Leaf fluence output factors did not increase significantly when leaves were opened beyond the two adjacent leaves. Conclusions: Hi-ART Tomotherapy unit has a very high dose output and inhomogeneous beam profiles owing to its special design of the treatment head. This may be useful in dose calculation and treatment delivery. (authors)

  4. Xerostomia in patients treated for oropharyngeal carcinoma: comparing linear accelerator-based intensity-modulated radiation therapy with helical tomotherapy.

    Science.gov (United States)

    Fortin, Israël; Fortin, Bernard; Lambert, Louise; Clavel, Sébastien; Alizadeh, Moein; Filion, Edith J; Soulières, Denis; Bélair, Manon; Guertin, Louis; Nguyen-Tan, Phuc Felix

    2014-09-01

    In comparison to sliding-window intensity-modulated radiation therapy (sw-IMRT), we hypothesized that helical tomotherapy (HT) would achieve similar locoregional control and, at the same time, decrease the parotid gland dose, thus leading to a xerostomia reduction. The association between radiation techniques, mean parotid dose, and xerostomia incidence, was reviewed in 119 patients with advanced oropharyngeal carcinoma treated with concurrent chemoradiation using sw-IMRT (n = 59) or HT (n = 60). Ipsilateral and contralateral parotid mean doses were significantly lower for patients treated with HT versus sw-IMRT: 24 Gy versus 32 Gy ipsilaterally and 20 Gy versus 25 Gy contralaterally. The incidence of grade ≥2 xerostomia was significantly lower in the HT group than in the sw-IMRT group: 12% versus 78% at 6 months, 3% versus 51% at 12 months, and 0% versus 25% at 24 months. Total parotid mean dose xerostomia at 6, 12, and 24 months. This retrospective series suggests that using HT can better spare the parotid glands while respecting quantitative analysis of normal tissue effects in the clinic (QUANTEC)'s criteria. Copyright © 2013 Wiley Periodicals, Inc.

  5. Dosimetric comparison between helical tomotherapy and intensity-modulated radiation therapy plans for non-small cell lung cancer.

    Science.gov (United States)

    Meng, Ling-Ling; Feng, Lin-Chun; Wang, Yun-Lai; Dai, Xiang-Kun; Xie, Chuan-Bin

    2011-06-01

    Helical tomotherapy (HT) is a new image-guided intensity-modulated radiation therapy (IMRT) technique. It is reported that HT plan for non-small-cell lung cancer (NSCLC) can give better dose uniformity, dose gradients, and protection for the lung than IMRT plan. We compared the dosimetric characteristics of HT for NSCLC with those of conventional IMRT to observe the superiority of HT. There was a comparative case series comprising 10 patients with NSCLC. Computed tomographic (CT) images of delineated targets were transferred to the PrecisePlan planning system (IMRT) and Tomo planning system (HT). The prescription doses were 70 Gy/33F for the gross tumor volume (GTV) and the visible lymph nodes (GTVnd), and 60 Gy/33F for the clinical target volume (CTV) and the clinical target volume of the visible lymph nodes (CTVnd). The dose restrictions for organs at risk were as follows: the maximum dose to spinal cord ≤ 45 Gy, V20 to the total lungs 0.05). The maximum doses to the spinal cord, heart, esophagus and trachea in the HT plan were lower than those in the IMRT plan, but the differences were not statistically significant. The HT plan provids better dose uniformity, dose gradients, and protection for the organs at risk. It can reduce the high-dose radiation volume for lung and the MLD, but may deliver a larger lung volume of low-dose radiation.

  6. Dosimetric comparison of helical tomotherapy, intensity-modulated radiation therapy, volumetric-modulated arc therapy, and 3-dimensional conformal therapy for the treatment of T1N0 glottic cancer

    International Nuclear Information System (INIS)

    Ekici, Kemal; Pepele, Eda K.; Yaprak, Bahaddin; Temelli, Oztun; Eraslan, Aysun F.; Kucuk, Nadir; Altınok, Ayse Y.; Sut, Pelin A.; Alpak, Ozlem D.; Colak, Cemil; Mayadagli, Alpaslan

    2016-01-01

    Various radiotherapy planning methods for T1N0 laryngeal cancer have been proposed to decrease normal tissue toxicity. We compare helical tomotherapy (HT), linac-based intensity-modulated radiation therapy (IMRT), volumetric-modulated arc therapy (VMAT), and 3-D conformal radiotherapy (3D-CRT) techniques for T1N0 laryngeal cancer. Overall, 10 patients with T1N0 laryngeal cancer were selected and evaluated. Furthermore, 10 radiotherapy treatment plans have been created for all 10 patients, including HT, IMRT, VMAT, and 3D-CRT. IMRT, VMAT, and HT plans vs 3D-CRT plans consistently provided superior planning target volume (PTV) coverage. Similar target coverage was observed between the 3 IMRT modalities. Compared with 3D-CRT, IMRT, HT, and VMAT significantly reduced the mean dose to the carotid arteries. VMAT resulted in the lowest mean dose to the submandibular and thyroid glands. Compared with 3D-CRT, IMRT, HT, and VMAT significantly increased the maximum dose to the spinal cord It was observed that the 3 IMRT modalities studied showed superior target coverage with less variation between each plan in comparison with 3D-CRT. The 3D-CRT plans performed better at the D max of the spinal cord. Clinical investigation is warranted to determine if these treatment approaches would translate into a reduction in radiation therapy–induced toxicities.

  7. Reference dosimetry for helical tomotherapy: Practical implementation and a multicenter validation

    International Nuclear Information System (INIS)

    De Ost, B.; Schaeken, B.; Vynckier, S.; Sterpin, E.; Van den Weyngaert, D.

    2011-01-01

    Purpose: The aim of this study was to implement a protocol for reference dosimetry in tomotherapy and to validate the beam output measurements with an independent dosimetry system. Methods: Beam output was measured at the reference depth of 10 cm in water for the following three cases: (1) a 5 x 10 cm 2 static machine specific reference field (MSR), (2) a rotational 5 x 10 cm 2 field without modulation and no tabletop in the beam, (3) a plan class specific reference (PCSR) field defined as a rotational homogeneous dose delivery to a cylindrical shaped target volume: plan with modulation and table-top movement. The formalism for reference dosimetry of small and nonstandard fields [Med.Phys.35: 5179-5186, 2008] and QA recommendations [Med.Phys.37: 4817-4853, 2010] were adopted in the dose measurement protocol. All ionization chamber measurements were verified independently using alanine/EPR dosimetry. As a pilot study, the beam output was measured on tomotherapy Hi-art systems at three other centers and directly compared to the centers specifications and to alanine dosimetry. Results: For the four centers, the mean static output at a depth of 10 cm in water and SAD = 85 cm, measured with an A1SL chamber following the TG-148 report was 6.238 Gy/min ± 0.058 (1 SD); the rotational output was 6.255 Gy/min ± 0.069 (1 SD). The dose stated by the center was found in good agreement with the measurements of the visiting team: D center /D visit = 1.000 ± 0.003 (1 SD). The A1SL chamber measurements were all in good agreement with Alanine/EPR dosimetry. Going from the static reference field to the rotational/non modulated field the dose rate remains constant within 0.2% except for one center where a deviation of 1.3% was detected. Conclusions: Following the TG-148 report, beam output measurements in water at the reference depth using a local protocol, as developed at different centers, was verified. The measurements were found in good agreement with alanine/EPR dosimetry. The

  8. A method for testing the performance and the accuracy of the binary MLC used in helical tomotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Lissner, Steffen; Schubert, Kai; Klueter, Sebastian; Oetzel, Dieter; Debus, Juergen [University Hospital Heidelberg (Germany). Dept. of Radiation Oncology

    2013-08-01

    During a helical tomotherapy a binary MLC is used for fluence modulation. The 64 pneumatically driven leaves of the MLC are either completely open or closed. Th e fast and frequent leaf movements result in a high demand of accuracy and stability of the MLC. This article is based on the analytical investigation of the accuracy and the stability of the MLC. Different patterns of MLC movements were generated to investigate the characteristics of the MLC. One of the considered aspects contains the friction between the leaves. The influence of variations of the compressed air on the MLC was also explored. The integrated MVCT detector of the tomotherapy system deposits the treatment data in a matrix. The detector is triggered with the linear accelerator, which is pulsed by 300Hz. The data matrix is available after the treatment. An IDL (Interactive Data Language) routine was programmed in order to analyse the matrix. The points of time, at which the leaves open (POT), and the period, in which the leaves stay open (LOT), were measured and compared with the desired values. That procedure has been repeated several times a week for approximately 6 months to investigate the stability of the MLC. Relative deviations of the LOT from -0.4% to -5.4% were measured. The friction between the leaves had no significant influence on the LOT. The available compressed air, that is used to move the leaves, depends on the number of moving leaves and also on the previous movements of the MLC. Variations of the compressed air resulted in deviations of the LOT from -1.8% to -3.7%. The measured POT deviates from the programmed POT up to -18.4ms {+-} 0.7ms. This maximal deviation correlates with a shift of the gantry angle of 0.52 which is negligible. The MLC has shown a stable behaviour over the 6 months. A separate consideration of the leaves showed no higher standard deviation of the LOT than {+-} 0.7ms during the investigated time. The variation between the different leaves is much higher

  9. A method for testing the performance and the accuracy of the binary MLC used in helical tomotherapy

    International Nuclear Information System (INIS)

    Lissner, Steffen; Schubert, Kai; Klueter, Sebastian; Oetzel, Dieter; Debus, Juergen

    2013-01-01

    During a helical tomotherapy a binary MLC is used for fluence modulation. The 64 pneumatically driven leaves of the MLC are either completely open or closed. Th e fast and frequent leaf movements result in a high demand of accuracy and stability of the MLC. This article is based on the analytical investigation of the accuracy and the stability of the MLC. Different patterns of MLC movements were generated to investigate the characteristics of the MLC. One of the considered aspects contains the friction between the leaves. The influence of variations of the compressed air on the MLC was also explored. The integrated MVCT detector of the tomotherapy system deposits the treatment data in a matrix. The detector is triggered with the linear accelerator, which is pulsed by 300Hz. The data matrix is available after the treatment. An IDL (Interactive Data Language) routine was programmed in order to analyse the matrix. The points of time, at which the leaves open (POT), and the period, in which the leaves stay open (LOT), were measured and compared with the desired values. That procedure has been repeated several times a week for approximately 6 months to investigate the stability of the MLC. Relative deviations of the LOT from -0.4% to -5.4% were measured. The friction between the leaves had no significant influence on the LOT. The available compressed air, that is used to move the leaves, depends on the number of moving leaves and also on the previous movements of the MLC. Variations of the compressed air resulted in deviations of the LOT from -1.8% to -3.7%. The measured POT deviates from the programmed POT up to -18.4ms ± 0.7ms. This maximal deviation correlates with a shift of the gantry angle of 0.52 which is negligible. The MLC has shown a stable behaviour over the 6 months. A separate consideration of the leaves showed no higher standard deviation of the LOT than ± 0.7ms during the investigated time. The variation between the different leaves is much higher than

  10. SU-F-T-435: Helical Tomotherapy for Craniospinal Irradiation: What We Have Learned from a Multi-Institutional Study

    Energy Technology Data Exchange (ETDEWEB)

    Du, D; Kaprealian, T; Low, D; Qi, X [University of California Los Angeles, Los Angeles, CA (United States); Han, C [City of Hope National Medical Center, Los Angeles, CA (United States); Chen, J; Perez-Andujar, A [University of California San Francisco, Lafayette, CA (United States); Lee, B [University of California, Los Angeles, Los Angeles, CA (United States)

    2016-06-15

    Purpose: To report cranio-spinal irradiation (CSI) planning experience, compare dosimetric quality and delivery efficiency with Tomotherapy from different institutions, and to investigate effect of planning parameters on plan quality and treatment time. Methods: Clinical helical tomotherapy IMRT plans for thirty-nine CSI cases from three academic institutions were retrospectively evaluated. The planning parameters: field width (FW), pitch, modulation factor (MF), and achieved dosimetric endpoints were cross-compared. A fraction-dose-delivery-timing index (FDTI), defined as treatment time per fraction dose per PTV length, was utilized to evaluate plan delivery efficiency. A lower FDTI indicates higher delivery efficiency. We studied the correlation between planning quality, treatment time and planning parameters by grouping the plans under specific planning parameters. Additionally, we created new plans using 5cm jaw for a subset of plans that used 2.5cm jaw to exam if treatment efficiency can be improved without sacrificing plan quality. Results: There were significant dosimetric differences for organ at risks (OARs) among different institutions (A,B,C). Using the lowest average MF (1.9±0.4) and 5cm field width, C had the highest lung, heart, kidney, liver mean doses and maximum doses for lens. Using the same field width of 5cm, but higher MF (2.6±0.6), B had lower doses to the OARs in the thorax and abdomen area. Most of A’s plans were planned with 2.5cm jaw, the plans yielded better PTV coverage, higher OAR doses and slightly shorter FDTI compared to institution B. The replanned 5cm jaw plans achieved comparable PTV coverage and OARs sparing, while saving up to 44.7% treatment time. Conclusion: Plan quality and delivery efficiency could vary significantly in CSI planning on Tomotheapy due to choice of different planning parameters. CSI plans using a 5cm jaw, with proper selection of pitch and MF, can achieve comparable/ better plan quality with shorter

  11. A phase II multi-institutional study assessing simultaneous in-field boost helical tomotherapy for 1-3 brain metastases

    International Nuclear Information System (INIS)

    Rodrigues, George; Yartsev, Slav; Tay, Keng Yeow; Pond, Gregory R; Lagerwaard, Frank; Bauman, Glenn

    2012-01-01

    Our research group has previously published a dosimetric planning study that demonstrated that a 60 Gy/10 fractions intralesional boost with whole-brain radiotherapy (WBRT) to 30 Gy/10 fractions was biologically equivalent with a stereotactic radiosurgery (SRS) boost of 18 Gy/1 fraction with 30 Gy/10 fractions WBRT. Helical tomotherapy (HT) was found to be dosimetrically equivalent to SRS in terms of target coverage and superior to SRS in terms of normal tissue tolerance. A phase I trial has been now completed at our institution with a total of 60 enrolled patients and 48 evaluable patients. The phase II dose has been determined to be the final phase I cohort dose of 60 Gy/10 fractions. The objective of this clinical trial is to subject the final phase I cohort dose to a phase II assessment of the endpoints of overall survival, intracranial control (ICC) and intralesional control (ILC). We hypothesize HT would be considered unsuitable for further study if the median OS for patients treated with the HT SIB technique is degraded by 2 months, or the intracranial progression-free rates (ICC and ILC) are inferior by 10% or greater compared to the expected results with treatment by whole brain plus SRS as defined by the RTOG randomized trial. A sample size of 93 patients was calculated based on these parameters as well as the statistical assumptions of alpha = 0.025 and beta = 0.1 due to multiple statistical testing. Secondary assessments of toxicity, health-related quality-of-life, cognitive changes, and tumor response are also integrated into this research protocol. To summarize, the purpose of this phase II trial is to assess this non-invasive alternative to SRS in terms of central nervous system (CNS) control when compared to SRS historical controls. A follow-up phase III trial may be required depending on the results of this trial in order to definitively assess non-inferiority/superiority of this approach. Ultimately, the purpose of this line of research is to

  12. Fast Megavoltage Computed Tomography: A Rapid Imaging Method for Total Body or Marrow Irradiation in Helical Tomotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Magome, Taiki [Department of Radiological Sciences, Faculty of Health Sciences, Komazawa University, Tokyo (Japan); Department of Radiology, The University of Tokyo Hospital, Tokyo (Japan); Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota (United States); Haga, Akihiro [Department of Radiology, The University of Tokyo Hospital, Tokyo (Japan); Takahashi, Yutaka [Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota (United States); Department of Radiation Oncology, Osaka University, Osaka (Japan); Nakagawa, Keiichi [Department of Radiology, The University of Tokyo Hospital, Tokyo (Japan); Dusenbery, Kathryn E. [Department of Therapeutic Radiology, University of Minnesota, Minneapolis, Minnesota (United States); Hui, Susanta K., E-mail: shui@coh.org [Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota (United States); Department of Therapeutic Radiology, University of Minnesota, Minneapolis, Minnesota (United States); Department of Radiation Oncology and Beckman Research Institute, City of Hope, Duarte, California (United States)

    2016-11-01

    Purpose: Megavoltage computed tomographic (MVCT) imaging has been widely used for the 3-dimensional (3-D) setup of patients treated with helical tomotherapy (HT). One drawback of MVCT is its very long imaging time, the result of slow couch speeds of approximately 1 mm/s, which can be difficult for the patient to tolerate. We sought to develop an MVCT imaging method allowing faster couch speeds and to assess its accuracy for image guidance for HT. Methods and Materials: Three cadavers were scanned 4 times with couch speeds of 1, 2, 3, and 4 mm/s. The resulting MVCT images were reconstructed using an iterative reconstruction (IR) algorithm with a penalty term of total variation and with a conventional filtered back projection (FBP) algorithm. The MVCT images were registered with kilovoltage CT images, and the registration errors from the 2 reconstruction algorithms were compared. This fast MVCT imaging was tested in 3 cases of total marrow irradiation as a clinical trial. Results: The 3-D registration errors of the MVCT images reconstructed with the IR algorithm were smaller than the errors of images reconstructed with the FBP algorithm at fast couch speeds (2, 3, 4 mm/s). The scan time and imaging dose at a speed of 4 mm/s were reduced to 30% of those from a conventional coarse mode scan. For the patient imaging, faster MVCT (3 mm/s couch speed) scanning reduced the imaging time and still generated images useful for anatomic registration. Conclusions: Fast MVCT with the IR algorithm is clinically feasible for large 3-D target localization, which may reduce the overall time for the treatment procedure. This technique may also be useful for calculating daily dose distributions or organ motion analyses in HT treatment over a wide area. Automated integration of this imaging is at least needed to further assess its clinical benefits.

  13. A comparative planning study of step-and-shoot IMRT versus helical tomotherapy for whole-pelvis irradiation in cervical cancer

    International Nuclear Information System (INIS)

    Chitapanarux, Imjai; Tharavichitkul, Ekkasit; Nobnop, Wannapa; Wanwilairat, Somsak; Vongtama, Roy; Traisathit, Patrinee

    2015-01-01

    The aim of this study was to compare the dosimetric parameters of whole-pelvis radiotherapy (WPRT) for cervical cancer between step-and-shoot IMRT (SaS-IMRT) and Helical Tomotherapy TM (HT). Retrospective analysis was performed on 20 cervical cancer patients who received WPRT in our center between January 2011 and January 2014. SaS-IMRT and HT treatment plans were generated for each patient. The dosimetric values for target coverage and organ-at-risk (OAR) sparing were compared according to the criteria of the International Commission on Radiation Units and Measurements 83 (ICRU 83) guidelines. Differences in beam-on time (BOT) were also compared. All the PTV dosimetric parameters (D5%, D50% and D95%) for the HT plan were (statistically significantly) of better quality than those for the SaS-IMRT plan (P-value < 0.001 in all respects). HT was also significantly more accurate than SaS-IMRT with respect to the D98% and Dmean of the CTV (P-values of 0.008 and <0.001, respectively). The median Conformity Index (CI) did not differ between the two plans (P-value = 0.057). However, the Uniformity Index for HT was significantly better than that for SaS-IMRT (P-value < 0.001). The median of D50% for the bladder, rectum and small bowel were significantly lower in HT planning than SaS-IMRT (P-value < 0.001). For D2%, we found that HT provided better sparing to the rectum and bladder (P-value < 0.001). However, the median of D2% for the small bowel was comparable for both plans. The median of Dmax of the head of the left femur was significantly lower in the HT plan, but this did not apply for the head of the right femur. BOT for HT was significantly shorter than for SaS-IMRT (P-value < 0.001). HT provided highly accurate plans, with more homogeneous PTV coverage and superior sparing of OARs than SaS-IMRT. In addition, HT enabled a shorter delivery time than SaS-IMRT. (author)

  14. Dosimetric Comparison of 6 MV and 15 MV Single Arc Rapidarc to Helical TomoTherapy for the Treatment of Pancreatic Cancer

    International Nuclear Information System (INIS)

    Cai Jing; Yue Jinbo; McLawhorn, Robert; Yang Wensha; Wijesooriya, Krishni; Dunlap, Neal E.; Sheng Ke; Yin Fangfang; Benedict, Stanley H.

    2011-01-01

    We conducted a planning study to compare Varian's RapidArc (RA) and helical TomoTherapy (HT) for the treatment of pancreatic cancer. Three intensity-modulated radiotherapy (IMRT) plans were generated for 8 patients with pancreatic cancer: one using HT with 6-MV beam (Plan HT6 ), one using single-arc RA with 6-MV beam (Plan RA6 ), and one using single-arc RA with 15-MV beam (Plan RA15 ). Dosimetric indices including high/low conformality index (CI 100% /CI 50% ), heterogeneity index (HI), monitor units (MUs), and doses to organs at risk (OARs) were compared. The mean CI 100% was statistically equivalent with respect to the 2 treatment techniques, as well as beam energy (0.99, 1.01, and 1.02 for Plan HT6 , Plan RA6 , and Plan RA156, respectively). The CI 50% and HI were improved in both RA plans over the HT plan. The RA plans significantly reduced MU (MU RA6 = 697, MU RA15 = 548) compared with HT (MU HT6 = 6177, p = 0.008 in both cases). The mean maximum cord dose was decreased from 29.6 Gy in Plan H T6 to 21.6 Gy (p = 0.05) in Plan RA6 and 21.7 Gy (p = 0.04) in Plan RA15 . The mean bowel dose decreased from 17.2 Gy in Plan HT6 to 15.2 Gy (p = 0.03) in Plan RA6 and 15.0 Gy (p = 0.03) Plan RA15 . The mean liver dose decreased from 8.4 Gy in Plan HT6 to 6.3 Gy (p = 0.04) in Plan RA6 and 6.2 Gy in Plan RA15 . Variations of the mean dose to the duodenum, kidneys, and stomach were statistically insignificant. RA and HT can both deliver conformal dose distributions to target volumes while limiting the dose to surrounding OARs in the treatment of pancreatic cancer. Dosimetric advantages might be gained by using RA over HT by reducing the dose to OARs and total MUs used for treatment.

  15. Stereotactic body radiation therapy via helical tomotherapy to replace brachytherapy for brachytherapy-unsuitable cervical cancer patients – a preliminary result

    Directory of Open Access Journals (Sweden)

    Hsieh CH

    2013-02-01

    Full Text Available Chen-Hsi Hsieh,1–3 Hui-Ju Tien,1 Sheng-Mou Hsiao,4 Ming-Chow Wei,4 Wen-Yih Wu,4 Hsu-Dong Sun,4 Li-Ying Wang,5 Yen-Ping Hsieh,6 Yu-Jen Chen,3,7–9 Pei-Wei Shueng1,101Department of Radiation Oncology, Far Eastern Memorial Hospital, Taipei, Taiwan; 2Department of Medicine, 3Institute of Traditional Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan; 4Department of Obstetrics and Gynecology, Far Eastern Memorial Hospital, Taipei, Taiwan; 5School and Graduate Institute of Physical Therapy, College of Medicine, National Taiwan University, Taipei, Taiwan; 6Department of Senior Citizen Service Management, National Taichung University of Science and Technology, Taichung, Taiwan; 7Department of Radiation Oncology, 8Department of Medical Research, Mackay Memorial Hospital, Taipei, Taiwan; 9Graduate Institute of Sport Coaching Science, Chinese Culture University, Taipei, Taiwan; 10Department of Radiation Oncology, National Defense Medical Center, Taipei, TaiwanAim: To review the experience and to evaluate the results of stereotactic body radiation therapy (SBRT via helical tomotherapy (HT, for the treatment of brachytherapy-unsuitable cervical cancer.Methods: Between September 1, 2008 to January 31, 2012, nine cervical cancer patients unsuitable for brachytherapy were enrolled. All of the patients received definitive whole pelvic radiotherapy with or without chemotherapy, followed by SBRT via HT.Results: The actuarial locoregional control rate at 3 years was 78%. The mean biological equivalent dose in 2-Gy fractions of the tumor, rectum, bladder, and intestines was 76.0 ± 7.3, 73.8 ± 13.2, 70.5 ± 10.0, and 43.1 ± 7.1, respectively. Only two had residual tumors after treatment, and the others were tumor-free. Two patients experienced grade 3 acute toxicity: one had diarrhea; and another experienced thrombocytopenia. There were no grade 3 or 4 subacute toxicities. Three patients suffered from manageable rectal bleeding in

  16. Efficacy of virtual block objects in reducing the lung dose in helical tomotherapy planning for cervical oesophageal cancer: a planning study.

    Science.gov (United States)

    Ito, Makoto; Shimizu, Hidetoshi; Aoyama, Takahiro; Tachibana, Hiroyuki; Tomita, Natsuo; Makita, Chiyoko; Koide, Yutaro; Kato, Daiki; Ishiguchi, Tsuneo; Kodaira, Takeshi

    2018-04-04

    Intensity-modulated radiotherapy is useful for cervical oesophageal carcinoma (CEC); however, increasing low-dose exposure to the lung may lead to radiation pneumonitis. Nevertheless, an irradiation technique that avoids the lungs has never been examined due to the high difficulty of dose optimization. In this study, we examined the efficacy of helical tomotherapy that can restrict beamlets passing virtual blocks during dose optimization computing (block plan) in reducing the lung dose. Fifteen patients with CEC were analysed. The primary/nodal lesion and prophylactic nodal region with adequate margins were defined as the planning target volume (PTV)-60 Gy and PTV-48 Gy, respectively. Nineteen plans per patient were made and compared (total: 285 plans), including non-block and block plans with several shapes and sizes. The most appropriate block model was semi-circular, 8 cm outside of the tracheal bifurcation, with a significantly lower lung dose compared to that of non-block plans; the mean lung volumes receiving 5 Gy, 10 Gy, 20 Gy, and the mean lung dose were 31.3% vs. 48.0% (p block and non-block plans were comparable in terms of the homogeneity and conformity indexes of PTV-60 Gy: 0.05 vs. 0.04 (p = 0.100) and 0.82 vs. 0.85 (p = 0.616), respectively. The maximum dose of the spinal cord planning risk volume increased slightly (49.4 Gy vs. 47.9 Gy, p = 0.002). There was no significant difference in the mean doses to the heart and the thyroid gland. Prolongation of the delivery time was less than 1 min (5.6 min vs. 4.9 min, p = 0.010). The block plan for CEC could significantly reduce the lung dose, with acceptable increment in the spinal dose and a slightly prolonged delivery time.

  17. Serial tomotherapy vs. MLC-IMRT (Multileaf Collimator Intensity Modulated Radiotherapy) for simultaneous boost treatment large intracerebral lesions

    International Nuclear Information System (INIS)

    Wolff, Dirk; Lohr, Frank; Mai, Sabine; Polednik, Martin; Wenz, Frederik; Dobler, Barbara

    2009-01-01

    Introduction: Recent data suggest that a radiosurgery boost treatment for up to three brain metastases in addition to whole brain radiotherapy (WBRT) is beneficial. Sequential treatment of multiple metastatic lesions is time-consuming and optimal normal tissue sparing is not trivial for larger metastases when separate plans are created and are only superimposed afterwards. Sequential Tomotherapy with noncoplanar arcs and Multi-field IMRT may streamline the process and enable easy simultaneous treatment. We compared plans for 2-3 intracerebral targets calculated with Intensity Modulated Radiotherapy (IMRT) based on treatment with MLC or sequential Tomotherapy using the Peacock-System. Treatment time was not to exceed 90 min on a linac with standart dose rate. MIMiC plans without treatment-time restrictions were created as a benchmark. Materials and methods: Calculations are based on a Siemens KD2 linac with a dose rate of 200 MU/min. Step-and-Shoot IMRT is performed with a standard MLC (2 x 29 leaves, 1 cm), serial Tomotherapy with the Multivane-Collimator MIMiC (NOMOS Inc. USA). Treatment plans are created with Corvus 5.0. To create plans with good conformity we chose a noncoplanar beam- and arc geometry for each approach (IMRT 4-, MIMiC 5-couch angles). The benchmark MIMiC plans with maximally steep dose gradients had 9 couch angles. For plan comparison reasons, 10Gy were prescribed to 90% of the PTV. Steepness of dose gradients, homogeneity and conformity were assessed by the following parameters: Volume encompassed by certain isodoses outside the target as well as homogeneity and conformity as indicated by Homogeneity- and Conformity-Index. Results: Plans without treatment-time restrictions had slightest dose to organ at risk (OAR), normal tissue and least Conformity-index. MIMiC- and MLC-IMRT based plans can be treated within the intended period of 90 min, all plans met the required dose. MLC based plans resulted in higher dose to organs at risk (OAR) and dose

  18. Cerebrospinal tomo-therapy; Tomotherapie cerebrospinale

    Energy Technology Data Exchange (ETDEWEB)

    Fumagalli, I.; Coche-Dequeant, B.; Lacornerie, T.; Reynaert, N.; Lartigau, E. [Centre Oscar-Lambret, 59 - Lille (France)

    2010-10-15

    The authors report the study of the feasibility of a cerebrospinal tomo-therapy, of the protection of organs at risk, and of tolerance. Nine patients have been treated, one with a bi-fractionated irradiation and the others with a conventional fractionation. Seven had chemotherapy before radiotherapy, and two had intensification with self-grafting of stem cells. The dose constraints and the planning target volume (PTV) differed with respect to the treated organ (kidney, lung, thyroid, parotid, hypophysis). The tolerance was good. It appears that cerebrospinal tomo-therapy results in a better comfort for the patient and an easier treatment plan with a good dose homogeneity. Short communication

  19. Stereotactic radiotherapy using tomotherapy for early-stage non-small cell lung carcinoma: analysis of intrafaction tumour motion

    International Nuclear Information System (INIS)

    Boggs, Drexell Hunter; Feigenberg, Steven; Walter, Robert; Wissing, Dennis; Patel, Bijal; Wu, Terry; Rosen, Lane

    2014-01-01

    Intrafraction tumour motion in helical tomotherapy was investigated by comparing pre- and mid-fraction CT scans in patients with early non-small cell lung carcinoma (NSCLC) to assess the efficacy of a 7-mm margin around gross tumour volumes (GTVs) in stereotactic body radiation therapy (SBRT). Thirty patients with early-stage NSCLC received SBRT in four or five fractions for a total of 141 treatments. A slow positron emission tomography/CT scan was fused with the simulation CT to determine the GTV. A planning target volume was created by placing an isotropic margin of 7mm around the GTV. Data were retrospectively analyzed to assess translational tumour positional changes along the x, y and z axes and vector changes in millimeters from the pretreatment megavoltage (MV)-CT to the mid-fraction MV-CT. Average movements for all 141 treatment days along the x, y and z axes were 0.5±2.3, −0.3±3.0 and 0.9±3.0mm, respectively. Average movements for each patient along the x, y and z axes were 0.5±1.5, −0.2±2.0 and 0.9±1.9mm, respectively. Average vector displacement was 4.3±2.4mm for all treatment days and 4.2±1.7mm for each patient. Of 141 treatments, 137 (97.2%) fell within 7.0mm in all axes. The addition of a 7-mm margin to the GTV for patients receiving SBRT for NSCLC using tomotherapy is adequate to account for tumour movement. Mid-fraction CT scans proved to be valuable in assessing intrafraction tumour motion.

  20. Encouraging Early Clinical Outcomes With Helical Tomotherapy-Based Image-Guided Intensity-Modulated Radiation Therapy for Residual, Recurrent, and/or Progressive Benign/Low-Grade Intracranial Tumors: A Comprehensive Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Tejpal [Department of Radiation Oncology, ACTREC/TMH, Tata Memorial Centre, Kharghar, Navi Mumbai (India); Wadasadawala, Tabassum; Master, Zubin; Phurailatpam, Reena; Pai-Shetty, Rajershi; Jalali, Rakesh [Department of Radiation Oncology, ACTREC/TMH, Tata Memorial Centre, Kharghar, Navi Mumbai (India)

    2012-02-01

    Purpose: To report early clinical outcomes of helical tomotherapy (HT)-based image-guided intensity-modulated radiation therapy (IMRT) in brain tumors of varying shape, size, and location. Materials and Methods: Patients with residual, recurrent, and/or progressive low-grade intracranial and skull-base tumors were treated on a prospective protocol of HT-based IMRT and followed clinicoradiologically. Standardized metrics were used for plan evaluation and outcome analysis. Results: Twenty-seven patients with 30 lesions were treated to a median radiotherapy dose of 54 Gy in 30 fractions. All HT plans resulted in excellent target volume coverage with steep dose-gradients. The mean (standard deviation) dose homogeneity index and conformity index was 0.07 (0.05) and 0.71 (0.08) respectively. At first response assessment, 20 of 30 lesions were stable, whereas 9 showed partial regression. One patient with a recurrent clival chordoma though neurologically stable showed imaging-defined progression, whereas another patient with stable disease on serial imaging had sustained neurologic worsening. With a median follow-up of 19 months (interquartile range, 11-26 months), the 2-year clinicoradiological progression-free survival and overall survival was 93.3% and 100% respectively. Conclusions: Careful selection of radiotherapy technique is warranted for benign/low-grade brain tumors to achieve durable local control with minimum long-term morbidity. Large or complex-shaped tumors benefit most from IMRT. Our early clinical experience of HT-based IMRT for brain tumors has been encouraging.

  1. 4D-CT scans reveal reduced magnitude of respiratory liver motion achieved by different abdominal compression plate positions in patients with intrahepatic tumors undergoing helical tomotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Yong, E-mail: hu.yong@zs-hospital.sh.cn; Zhou, Yong-Kang, E-mail: zhouyk2009@163.com; Chen, Yi-Xing, E-mail: chen.yixing@zs-hospital.sh.cn; Shi, Shi-Ming, E-mail: shiming32@126.com; Zeng, Zhao-Chong, E-mail: zeng.zhaochong@zs-hospital.sh.cn [Department of Radiation Oncology, Zhongshan Hospital, Fudan University, 180 Feng Lin Road, Shanghai 200032 (China)

    2016-07-15

    Purpose: While abdominal compression (AC) can be used to reduce respiratory liver motion in patients receiving helical tomotherapy for hepatocellular carcinoma, the nature and extent of this effect is not well described. The purpose of this study was to evaluate the changes in magnitude of three-dimensional liver motion with abdominal compression using four-dimensional (4D) computed tomography (CT) images of several plate positions. Methods: From January 2012 to October 2015, 72 patients with intrahepatic carcinoma and divided into four groups underwent 4D-CT scans to assess respiratory liver motion. Of the 72 patients, 19 underwent abdominal compression of the cephalic area between the subxiphoid and umbilicus (group A), 16 underwent abdominal compression of the caudal region between the subxiphoid area and the umbilicus (group B), 11 patients underwent abdominal compression of the caudal umbilicus (group C), and 26 patients remained free breathing (group D). 4D-CT images were sorted into ten-image series, according to the respiratory phase from the end inspiration to the end expiration, and then transferred to treatment planning software. All liver contours were drawn by a single physician and confirmed by a second physician. Liver relative coordinates were automatically generated to calculate the liver respiratory motion in different axial directions to compile the 10 ten contours into a single composite image. Differences in respiratory liver motion were assessed with a one-way analysis of variance test of significance. Results: The average respiratory liver motion in the Y axial direction was 4.53 ± 1.16, 7.56 ± 1.30, 9.95 ± 2.32, and 9.53 ± 2.62 mm in groups A, B, C, and D, respectively, with a significant change among the four groups (p < 0.001). Abdominal compression was most effective in group A (compression plate on the subxiphoid area), with liver displacement being 2.53 ± 0.93, 4.53 ± 1.16, and 2.14 ± 0.92 mm on the X-, Y-, and Z

  2. Impact of the Lok-bar for High-precision Radiotherapy with Tomotherapy.

    Science.gov (United States)

    Hirata, Makoto; Monzen, Hajime; Tamura, Mikoto; Kubo, Kazuki; Matsumoto, Kenji; Hanaoka, Kohei; Okumura, Masahiko; Nishimura, Yasumasa

    2018-05-01

    Patient immobilization systems are used to establish a reproducible patient position relative to the couch. In this study, the impact of conventional lok-bars for CT-simulation (CIVCO-bar) and treatment (iBEAM-bar) were compared with a novel lok-bar (mHM-bar) in tomotherapy. Verification was obtained as follows: i. artifacts in CT images; ii. dose attenuation rate of lok-bar, compared to without lok-bar; and iii. dose differences between the calculated and measured absorbed doses. With the CIVCO-bar, there were obvious metal artifacts, while there were nearly no artifacts with the mHM-bar. The mean dose attenuation rates with the mHM-bar and iBEAM-bar were 1.31% and 2.28%, and the mean dose difference was 1.55% and 1.66% for mHM-bar and iBEAM-bar. Using the mHM-bar reduced artifacts on the CT image and improved dose attenuation are obtained. The lok-bar needs to be inserted as a structure set in treatment planning with tomotherapy. Copyright© 2018, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

  3. Cerebrospinal tomo-therapy

    International Nuclear Information System (INIS)

    Fumagalli, I.; Coche-Dequeant, B.; Lacornerie, T.; Reynaert, N.; Lartigau, E.

    2010-01-01

    The authors report the study of the feasibility of a cerebrospinal tomo-therapy, of the protection of organs at risk, and of tolerance. Nine patients have been treated, one with a bi-fractionated irradiation and the others with a conventional fractionation. Seven had chemotherapy before radiotherapy, and two had intensification with self-grafting of stem cells. The dose constraints and the planning target volume (PTV) differed with respect to the treated organ (kidney, lung, thyroid, parotid, hypophysis). The tolerance was good. It appears that cerebrospinal tomo-therapy results in a better comfort for the patient and an easier treatment plan with a good dose homogeneity. Short communication

  4. Helical Tomotherapy-Based STAT Stereotactic Body Radiation Therapy: Dosimetric Evaluation for a Real-Time SBRT Treatment Planning and Delivery Program

    International Nuclear Information System (INIS)

    Dunlap, Neal; McIntosh, Alyson; Sheng Ke; Yang Wensha; Turner, Benton; Shoushtari, Asal; Sheehan, Jason; Jones, David R.; Lu Weigo; Ruchala, Keneth; Olivera, Gustavo; Parnell, Donald; Larner, James L.; Benedict, Stanley H.; Read, Paul W.

    2010-01-01

    Stereotactic body radiation therapy (SBRT) treatments have high-dose gradients and even slight patient misalignment from the simulation to treatment could lead to target underdosing or organ at risk (OAR) overdosing. Daily real-time SBRT treatment planning could minimize the risk of geographic miss. As an initial step toward determining the clinical feasibility of developing real-time SBRT treatment planning, we determined the calculation time of helical TomoTherapy-based STAT radiation therapy (RT) treatment plans for simple liver, lung, and spine SBRT treatments to assess whether the planning process was fast enough for practical clinical implementation. Representative SBRT planning target volumes for hypothetical liver, peripheral lung, and thoracic spine lesions and adjacent OARs were contoured onto a planning computed tomography scan (CT) of an anthropomorphic phantom. Treatment plans were generated using both STAT RT 'full scatter' and conventional helical TomoTherapy 'beamlet' algorithms. Optimized plans were compared with respect to conformality index (CI), heterogeneity index (HI), and maximum dose to regional OARs to determine clinical equivalence and the number of required STAT RT optimization iterations and calculation times were determined. The liver and lung dosimetry for the STAT RT and standard planning algorithms were clinically and statistically equivalent. For the liver lesions, 'full scatter' and 'beamlet' algorithms showed a CI of 1.04 and 1.04 and HI of 1.03 and 1.03, respectively. For the lung lesions, 'full scatter' and 'beamlet' algorithms showed a CI of 1.05 and 1.03 and HI of 1.05and 1.05, respectively. For spine lesions, 'full scatter' and 'beamlet' algorithms showed a CI of 1.15 and 1.14 and HI of 1.22 and 1.14, respectively. There was no difference between treatment algorithms with respect to maximum doses to the OARs. The STAT RT iteration time with current treatment planning systems is 45 sec, and the treatment planning required 3

  5. Patient- and therapy-related factors associated with the incidence of xerostomia in nasopharyngeal carcinoma patients receiving parotid-sparing helical tomotherapy.

    Science.gov (United States)

    Lee, Tsair-Fwu; Liou, Ming-Hsiang; Ting, Hui-Min; Chang, Liyun; Lee, Hsiao-Yi; Wan Leung, Stephen; Huang, Chih-Jen; Chao, Pei-Ju

    2015-08-20

    We investigated the incidence of moderate to severe patient-reported xerostomia among nasopharyngeal carcinoma (NPC) patients treated with helical tomotherapy (HT) and identified patient- and therapy-related factors associated with acute and chronic xerostomia toxicity. The least absolute shrinkage and selection operator (LASSO) normal tissue complication probability (NTCP) models were developed using quality-of-life questionnaire datasets from 67 patients with NPC. For acute toxicity, the dosimetric factors of the mean doses to the ipsilateral submandibular gland (Dis) and the contralateral submandibular gland (Dcs) were selected as the first two significant predictors. For chronic toxicity, four predictive factors were selected: age, mean dose to the oral cavity (Doc), education, and T stage. The substantial sparing data can be used to avoid xerostomia toxicity. We suggest that the tolerance values corresponded to a 20% incidence of complications (TD20) for Dis = 39.0 Gy, Dcs = 38.4 Gy, and Doc = 32.5 Gy, respectively, when mean doses to the parotid glands met the QUANTEC 25 Gy sparing guidelines. To avoid patient-reported xerostomia toxicity, the mean doses to the parotid gland, submandibular gland, and oral cavity have to meet the sparing tolerance, although there is also a need to take inherent patient characteristics into consideration.

  6. Tomotherapy: IMRT and tomographic verification

    International Nuclear Information System (INIS)

    Mackie, T.R.

    2000-01-01

    include MLC's and many clinics use them to replace 90% or more of the field-shaping requirements of conventional radiotherapy. Now, several academic centers are treating patients with IMRT using conventional MLC's to modulate the field. IMRT using conventional MLC's have the advantage that the patient is stationary during the treatment and the MLC's can be used in conventional practice. Nevertheless, tomotherapy using the Peacock system delivers the most conformal dose distributions of any commercial system to date. The biggest limitation with the both the NOMOS Peacock tomotherapy system and conventional MLC's for IMRT delivery is the lack of treatment verification. In conventional few-field radiotherapy one relied on portal images to determine if the patient was setup correctly and the beams were correctly positioned. With IMRT the image contrast is superimposed on the beam intensity variation. Conventional practice allowed for monitor unit calculation checks and point dosimeters placed on the patient's surface to verify that the treatment was properly delivered. With IMRT it is impossible to perform hand calculations of monitor units and dosimeters placed on the patient's surface are prone to error due to high gradients in the beam intensity. NOMOS has developed a verification phantom that allows multiple sheets of film to be placed in a light-tight box that is irradiated with the same beam pattern that is used to treat the patient. The optical density of the films are adjusted, normalized, and calibrated and then quantitatively compared with the dose calculated for the phantom delivery. However, this process is too laborious to be used for patient-specific QA. If IMRT becomes ubiquitous and it can be shown that IMRT is useful on most treatment sites then there is a need to design treatment units dedicated to IMRT delivery and verification. Helical tomotherapy is such a redesign. Helical tomotherapy is the delivery of a rotational fan beam while the patient is

  7. Dose-volume histogram comparison between static 5-field IMRT with 18-MV X-rays and helical tomotherapy with 6-MV X-rays.

    Science.gov (United States)

    Hayashi, Akihiro; Shibamoto, Yuta; Hattori, Yukiko; Tamura, Takeshi; Iwabuchi, Michio; Otsuka, Shinya; Sugie, Chikao; Yanagi, Takeshi

    2015-03-01

    We treated prostate cancer patients with static 5-field intensity-modulated radiation therapy (IMRT) using linac 18-MV X-rays or tomotherapy with 6-MV X-rays. As X-ray energies differ, we hypothesized that 18-MV photon IMRT may be better for large patients and tomotherapy may be more suitable for small patients. Thus, we compared dose-volume parameters for the planning target volume (PTV) and organs at risk (OARs) in 59 patients with T1-3 N0M0 prostate cancer who had been treated using 5-field IMRT. For these same patients, tomotherapy plans were also prepared for comparison. In addition, plans of 18 patients who were actually treated with tomotherapy were analyzed. The evaluated parameters were homogeneity indicies and a conformity index for the PTVs, and D2 (dose received by 2% of the PTV in Gy), D98, Dmean and V10-70 Gy (%) for OARs. To evaluate differences by body size, patients with a known body mass index were grouped by that index ( 25 kg/m(2)). For the PTV, all parameters were higher in the tomotherapy plans compared with the 5-field IMRT plans. For the rectum, V10 Gy and V60 Gy were higher, whereas V20 Gy and V30 Gy were lower in the tomotherapy plans. For the bladder, all parameters were higher in the tomotherapy plans. However, both plans were considered clinically acceptable. Similar trends were observed in 18 patients treated with tomotherapy. Obvious trends were not observed for body size. Tomotherapy provides equivalent dose distributions for PTVs and OARs compared with 18-MV 5-field IMRT. Tomotherapy could be used as a substitute for high-energy photon IMRT for prostate cancer regardless of body size. © The Author 2015. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

  8. Three-dimensional analysis of the respiratory interplay effect in helical tomotherapy: Baseline variations cause the greater part of dose inhomogeneities seen.

    Science.gov (United States)

    Tudor, G Samuel J; Harden, Susan V; Thomas, Simon J

    2014-03-01

    Dose differences from those planned can occur due to the respiratory interplay effect on helical tomotherapy. The authors present a technique to calculate single-fraction doses in three-dimensions resulting from craniocaudal motion applied to a patient CT set. The technique is applied to phantom and patient plans using patient respiratory traces. An additional purpose of the work is to determine the contribution toward the interplay effect of different components of the respiratory trace. MATLAB code used to calculate doses to a CT dataset from a helical tomotherapy plan has been modified to permit craniocaudal motion and improved temporal resolution. Real patient traces from seven patients were applied to ten phantom plans of differing field width, modulation factor, pitch and fraction dose, and simulations made with peak-to-peak amplitudes ranging from 0 to 2.5 cm. PTV voxels near the superior or inferior limits of the PTV are excluded from the analysis. The maximum dose discrepancy compared with the static case recorded along with the proportion of voxels receiving more than 10% and 20% different from prescription dose. The analysis was repeated with the baseline variation of the respiratory trace removed, leaving the cyclic component of motion only. Radiochromic film was used on one plan-trace combination and compared with the software simulation. For one case, filtered traces were generated and used in simulations which consisted only of frequencies near to particular characteristic frequencies of the treatment delivery. Intraslice standard deviation of dose differences was used to identify potential MLC interplay, which was confirmed using nonmodulated simulations. Software calculations were also conducted for four realistic patient plans and modeling movement of a patient CT set with amplitudes informed by the observed motion of the GTV on 4DCT. The maximum magnitude of dose difference to a PTV voxel due to the interplay effect within a particular plan

  9. Evaluation of the optimal combinations of modulation factor and pitch for Helical TomoTherapy plans made with TomoEdge using Pareto optimal fronts.

    Science.gov (United States)

    De Kerf, Geert; Van Gestel, Dirk; Mommaerts, Lobke; Van den Weyngaert, Danielle; Verellen, Dirk

    2015-09-17

    Modulation factor (MF) and pitch have an impact on Helical TomoTherapy (HT) plan quality and HT users mostly use vendor-recommended settings. This study analyses the effect of these two parameters on both plan quality and treatment time for plans made with TomoEdge planning software by using the concept of Pareto optimal fronts. More than 450 plans with different combinations of pitch [0.10-0.50] and MF [1.2-3.0] were produced. These HT plans, with a field width (FW) of 5 cm, were created for five head and neck patients and homogeneity index, conformity index, dose-near-maximum (D2), and dose-near-minimum (D98) were analysed for the planning target volumes, as well as the mean dose and D2 for most critical organs at risk. For every dose metric the median value will be plotted against treatment time. A Pareto-like method is used in the analysis which will show how pitch and MF influence both treatment time and plan quality. For small pitches (≤0.20), MF does not influence treatment time. The contrary is true for larger pitches (≥0.25) as lowering MF will both decrease treatment time and plan quality until maximum gantry speed is reached. At this moment, treatment time is saturated and only plan quality will further decrease. The Pareto front analysis showed optimal combinations of pitch [0.23-0.45] and MF > 2.0 for a FW of 5 cm. Outside this range, plans will become less optimal. As the vendor-recommended settings fall within this range, the use of these settings is validated.

  10. Effect of image value-to-density table (IVDT) on the accuracy of delivery quality assurance (DQA) process in helical tomotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Song, Ju-Young [Department of Radiation Oncology, Chonnam National University Medical School, Gwangju (Korea, Republic of); Ahn, Sung-Ja, E-mail: dandy@catholic.ac.kr [Department of Radiation Oncology, Chonnam National University Medical School, Gwangju (Korea, Republic of)

    2012-10-01

    The effect of the accuracy in the application of the image value-to-density table (IVDT) from kilovoltage computed tomography (kVCT) and mega-voltage computed tomography (MVCT) images on the delivery quality assurance (DQA) in helical tomotherapy (HT) was analyzed. The DQA plans were prepared with a kVCT image of a cheese phantom for 10 HT patients, and the difference in absolute dose equivalence between the planned and real measurement was evaluated according to the accuracy of IVDT application. The difference between the calculated dose distribution and real dose distribution measured with MapCHECK (SunNuclear, Melbourne, FL) was analyzed through the DQA process with a kVCT MapCHECK image and the same analysis was performed with an MVCT MapCHECK image. The IVDT for kVCT was applied to MVCT and the variation in error between the planned and real measurement caused by improper application of IVDT was evaluated. The accuracy of the IVDT application in the homogeneous water-equivalent cheese phantom had only a minor influence on the dose calculation. Although the overall accuracy of the calculated dose was increased when the proper IVDT was applied, this result had no statistical significance. The MVCT image of MapCHECK contained less error between the calculated dose and delivered dose with a high pass rate. The proper IVDT application to the MVCT image of MapCHECK increased the accuracy of dose calculation, and this result had a statistical significance. Application of the correct IVDT is important in HT DQA and its significance is increased when using phantoms consisting of inhomogeneous density materials.

  11. Health-related quality of life in survivors of stage I-II breast cancer: randomized trial of post-operative conventional radiotherapy and hypofractionated tomotherapy

    Directory of Open Access Journals (Sweden)

    Versmessen Harijati

    2012-10-01

    Full Text Available Abstract Background Health-related quality of life (HRQOL assessment is a key component of clinical oncology trials. However, few breast cancer trials comparing adjuvant conventional radiotherapy (CR and hypofractionated tomotherapy (TT have investigated HRQOL. We compared HRQOL in stage I-II breast cancer patients who were randomized to receive either CR or TT. Tomotherapy uses an integrated computed tomography scanner to improve treatment accuracy, aiming to reduce the adverse effects of radiotherapy. Methods A total of 121 stage I–II breast cancer patients who had undergone breast conserving surgery (BCS or mastectomy (MA were randomly assigned to receive either CR or TT. CR patients received 25 × 2 Gy over 5 weeks, and BCS patients also received a sequential boost of 8 × 2 Gy over 2 weeks. TT patients received 15 × 2.8 Gy over 3 weeks, and BCS patients also received a simultaneous integrated boost of 15 × 0.6 Gy over 3 weeks. Patients completed the EORTC QLQ-C30 and BR23 questionnaires. The mean score (± standard error was calculated at baseline, the end of radiotherapy, and at 3 months and 1, 2, and 3 years post-radiotherapy. Data were analyzed by the 'intention-to-treat' principle. Results On the last day of radiotherapy, patients in both treatment arms had decreased global health status and functioning scores; increased fatigue (clinically meaningful in both treatment arms, nausea and vomiting, and constipation; decreased arm symptoms; clinically meaningful increased breast symptoms in CR patients and systemic side effects in TT patients; and slightly decreased body image and future perspective. At 3 months post-radiotherapy, TT patients had a clinically significant increase in role- and social-functioning scores and a clinically significant decrease in fatigue. The post-radiotherapy physical-, cognitive- and emotional-functioning scores improved faster in TT patients than CR patients. TT patients also had a better

  12. Health-related quality of life in survivors of stage I-II breast cancer: randomized trial of post-operative conventional radiotherapy and hypofractionated tomotherapy

    International Nuclear Information System (INIS)

    Versmessen, Harijati; Vinh-Hung, Vincent; Van Parijs, Hilde; Miedema, Geertje; Voordeckers, Mia; Adriaenssens, Nele; Storme, Guy; De Ridder, Mark

    2012-01-01

    Health-related quality of life (HRQOL) assessment is a key component of clinical oncology trials. However, few breast cancer trials comparing adjuvant conventional radiotherapy (CR) and hypofractionated tomotherapy (TT) have investigated HRQOL. We compared HRQOL in stage I-II breast cancer patients who were randomized to receive either CR or TT. Tomotherapy uses an integrated computed tomography scanner to improve treatment accuracy, aiming to reduce the adverse effects of radiotherapy. A total of 121 stage I–II breast cancer patients who had undergone breast conserving surgery (BCS) or mastectomy (MA) were randomly assigned to receive either CR or TT. CR patients received 25 × 2 Gy over 5 weeks, and BCS patients also received a sequential boost of 8 × 2 Gy over 2 weeks. TT patients received 15 × 2.8 Gy over 3 weeks, and BCS patients also received a simultaneous integrated boost of 15 × 0.6 Gy over 3 weeks. Patients completed the EORTC QLQ-C30 and BR23 questionnaires. The mean score (± standard error) was calculated at baseline, the end of radiotherapy, and at 3 months and 1, 2, and 3 years post-radiotherapy. Data were analyzed by the 'intention-to-treat' principle. On the last day of radiotherapy, patients in both treatment arms had decreased global health status and functioning scores; increased fatigue (clinically meaningful in both treatment arms), nausea and vomiting, and constipation; decreased arm symptoms; clinically meaningful increased breast symptoms in CR patients and systemic side effects in TT patients; and slightly decreased body image and future perspective. At 3 months post-radiotherapy, TT patients had a clinically significant increase in role- and social-functioning scores and a clinically significant decrease in fatigue. The post-radiotherapy physical-, cognitive- and emotional-functioning scores improved faster in TT patients than CR patients. TT patients also had a better long-term recovery from fatigue than CR patients. ANOVA

  13. Extended helical tomo-therapy and concomitant chemotherapy for an uterine cervix carcinoma: dosimetry parameters and hematological toxicity; Tomotherapie helicoidale etendue et chimiotherapie concomitante pour un cancer du col de l'uterus: parametres dosimetriques et toxicite hematologique

    Energy Technology Data Exchange (ETDEWEB)

    Haddad, H.; Thomas, L.; Belhomme, S.; Chemin, A.; Caron, J.; Dejean, C.; Kantor, G.; Richaud, P. [Institut Bergonie, Dept. de Radiotherapie, 33 - Bordeaux (France); Floquet, A.; Guyon, F. [Institut Bergonie, Dept. de Chirurgie, 33 - Bordeaux (France)

    2009-10-15

    the extended tomo-therapy associated to concomitant chemotherapy is feasible and allows a dose escalation at the ganglions level. It is necessary to continue to study the dosimetry parameters at the hematopoietic marrow level that are predictive for a hematological toxicity. (N.C.)

  14. Maximum likelihood as a common computational framework in tomotherapy

    International Nuclear Information System (INIS)

    Olivera, G.H.; Shepard, D.M.; Reckwerdt, P.J.; Ruchala, K.; Zachman, J.; Fitchard, E.E.; Mackie, T.R.

    1998-01-01

    Tomotherapy is a dose delivery technique using helical or axial intensity modulated beams. One of the strengths of the tomotherapy concept is that it can incorporate a number of processes into a single piece of equipment. These processes include treatment optimization planning, dose reconstruction and kilovoltage/megavoltage image reconstruction. A common computational technique that could be used for all of these processes would be very appealing. The maximum likelihood estimator, originally developed for emission tomography, can serve as a useful tool in imaging and radiotherapy. We believe that this approach can play an important role in the processes of optimization planning, dose reconstruction and kilovoltage and/or megavoltage image reconstruction. These processes involve computations that require comparable physical methods. They are also based on equivalent assumptions, and they have similar mathematical solutions. As a result, the maximum likelihood approach is able to provide a common framework for all three of these computational problems. We will demonstrate how maximum likelihood methods can be applied to optimization planning, dose reconstruction and megavoltage image reconstruction in tomotherapy. Results for planning optimization, dose reconstruction and megavoltage image reconstruction will be presented. Strengths and weaknesses of the methodology are analysed. Future directions for this work are also suggested. (author)

  15. Helical Tomotherapy for Whole-Brain Irradiation With Integrated Boost to Multiple Brain Metastases: Evaluation of Dose Distribution Characteristics and Comparison With Alternative Techniques

    International Nuclear Information System (INIS)

    Levegrün, Sabine; Pöttgen, Christoph; Wittig, Andrea; Lübcke, Wolfgang; Abu Jawad, Jehad; Stuschke, Martin

    2013-01-01

    Purpose: To quantitatively evaluate dose distribution characteristics achieved with helical tomotherapy (HT) for whole-brain irradiation (WBRT) with integrated boost (IB) to multiple brain metastases in comparison with alternative techniques. Methods and Materials: Dose distributions for 23 patients with 81 metastases treated with WBRT (30 Gy/10 fractions) and IB (50 Gy) were analyzed. The median number of metastases per patient (N mets ) was 3 (range, 2-8). Mean values of the composite planning target volume of all metastases per patient (PTV mets ) and of the individual metastasis planning target volume (PTV ind met ) were 8.7 ± 8.9 cm 3 (range, 1.3-35.5 cm 3 ) and 2.5 ± 4.5 cm 3 (range, 0.19-24.7 cm 3 ), respectively. Dose distributions in PTV mets and PTV ind met were evaluated with respect to dose conformity (conformation number [CN], RTOG conformity index [PITV]), target coverage (TC), and homogeneity (homogeneity index [HI], ratio of maximum dose to prescription dose [MDPD]). The dependence of dose conformity on target size and N mets was investigated. The dose distribution characteristics were benchmarked against alternative irradiation techniques identified in a systematic literature review. Results: Mean ± standard deviation of dose distribution characteristics derived for PTV mets amounted to CN = 0.790 ± 0.101, PITV = 1.161 ± 0.154, TC = 0.95 ± 0.01, HI = 0.142 ± 0.022, and MDPD = 1.147 ± 0.029, respectively, demonstrating high dose conformity with acceptable homogeneity. Corresponding numbers for PTV ind met were CN = 0.708 ± 0.128, PITV = 1.174 ± 0.237, TC = 0.90 ± 0.10, HI = 0.140 ± 0.027, and MDPD = 1.129 ± 0.030, respectively. The target size had a statistically significant influence on dose conformity to PTV mets (CN = 0.737 for PTV mets ≤4.32 cm 3 vs CN = 0.848 for PTV mets >4.32 cm 3 , P=.006), in contrast to N mets . The achieved dose conformity to PTV mets , assessed by both CN and PITV, was in all investigated volume strata

  16. Feasibility of Tomotherapy-based image-guided radiotherapy to reduce aspiration risk in patients with non-laryngeal and non-pharyngeal head and neck cancer.

    Directory of Open Access Journals (Sweden)

    Nam P Nguyen

    Full Text Available PURPOSE: The study aims to assess the feasibility of Tomotherapy-based image-guided radiotherapy (IGRT to reduce the aspiration risk in patients with non-laryngeal and non-hypopharyngeal cancer. A retrospective review of 48 patients undergoing radiation for non-laryngeal and non-hypopharyngeal head and neck cancers was conducted. All patients had a modified barium swallow (MBS prior to treatment, which was repeated one month following radiotherapy. Mean middle and inferior pharyngeal dose was recorded and correlated with the MBS results to determine aspiration risk. RESULTS: Mean pharyngeal dose was 23.2 Gy for the whole group. Two patients (4.2% developed trace aspiration following radiotherapy which resolved with swallowing therapy. At a median follow-up of 19 months (1-48 months, all patients were able to resume normal oral feeding without aspiration. CONCLUSION AND CLINICAL RELEVANCE: IGRT may reduce the aspiration risk by decreasing the mean pharyngeal dose in the presence of large cervical lymph nodes. Further prospective studies with IGRT should be performed in patients with non-laryngeal and non-hypopharyngeal head and neck cancers to verify this hypothesis.

  17. Postoperative Radiotherapy for Prostate Cancer: A Comparison of Four Consensus Guidelines and Dosimetric Evaluation of 3D-CRT Versus Tomotherapy IMRT

    International Nuclear Information System (INIS)

    Malone, Shawn; Croke, Jennifer; Roustan-Delatour, Nicolas; Belanger, Eric; Avruch, Leonard; Malone, Colin; Morash, Christopher; Kayser, Cathleen; Underhill, Kathryn; Li Yan; Malone, Kyle; Nyiri, Balazs; Spaans, Johanna

    2012-01-01

    Purpose: Despite the benefits of adjuvant radiotherapy after radical prostatectomy, approximately one-half of patients relapse. Four consensus guidelines have been published (European Organization for Research and Treatment of Cancer, Faculty of Radiation Oncology Genito-Urinary Group, Princess Margaret Hospital, Radiation Therapy Oncology Group) with the aim of standardizing the clinical target volume (CTV) delineation and improve outcomes. To date, no attempt has been made to compare these guidelines in terms of treatment volumes or organ at risk (OAR) irradiation. The extent to which the guideline-derived plans meet the dosimetric constraints of present trials or of the Quantitative Analysis of Normal Tissue Effects in the Clinic (QUANTEC) trial is also unknown. Our study also explored the dosimetric benefits of intensity-modulated radiotherapy (IMRT). Methods and Materials: A total of 20 patients treated with postoperative RT were included. The three-dimensional conformal radiotherapy (3D-CRT) plans were applied to cover the guideline-generated planning target volumes (66 Gy in 33 fractions). Dose–volume histograms (DVHs) were analyzed for CTV/planning target volume coverage and to evaluate OAR irradiation. The OAR DVHs were compared with the constraints proposed in the QUANTEC and Radiotherapy and Androgen Deprivation In Combination After Local Surgery (RADICALS) trials. 3D-CRT plans were compared with the tomotherapy plans for the Radiation Therapy Oncology Group planning target volume to evaluate the advantages of IMRT. Results: The CTV differed significantly between guidelines (p < 0.001). The European Organization for Research and Treatment of Cancer-CTVs were significantly smaller than the other CTVs (p < 0.001). Differences in prostate bed coverage superiorly accounted for the major volumetric differences between the guidelines. Using 3D-CRT, the DVHs rarely met the QUANTEC or RADICALS rectal constraints, independent of the guideline used. The RADICALS

  18. MO-FG-BRA-07: Intrafractional Motion Effect Can Be Minimized in Tomotherapy Stereotactic Body Radiotherapy (SBRT)

    Energy Technology Data Exchange (ETDEWEB)

    Price, A; Chang, S; Matney, J; Wang, A; Lian, J [University of North Carolina, Chapel Hill, NC (United States); Chao, E [Accuray Incorporated, Madison, WI (United States)

    2016-06-15

    Purpose: Tomotherapy has unique challenges in handling intrafractional motion compared to conventional LINAC. In this study, we analyzed the impact of intrafractional motion on cumulative dosimetry using actual patient motion data and investigated real time jaw/MLC compensation approaches to minimize the motion-induced dose discrepancy in Tomotherapy SBRT treatment. Methods: Intrafractional motion data recorded in two CyberKnife lung treatment cases through fiducial tracking and two LINAC prostate cases through Calypso tracking were used in this study. For each treatment site, one representative case has an average motion (6mm) and one has a large motion (10mm for lung and 15mm for prostate). The cases were re-planned on Tomotherapy for SBRT. Each case was planned with 3 different jaw settings: 1cm static, 2.5cm dynamic, and 5cm dynamic. 4D dose accumulation software was developed to compute dose with the recorded motions and theoretically compensate motions by modifying original jaw and MLC to track the trajectory of the tumor. Results: PTV coverage in Tomotherapy SBRT for patients with intrafractional motion depends on motion type, amplitude and plan settings. For the prostate patient with large motion, PTV coverage changed from 97.2% (motion-free) to 47.1% (target motion-included), 96.6% to 58.5% and 96.3% to 97.8% for the 1cm static jaw, 2.5cm dynamic jaw and 5cm dynamic jaw setting, respectively. For the lung patient with large motion, PTV coverage discrepancies showed a similar trend of change. When the jaw and MLC compensation program was engaged, the motion compromised PTV coverage was recovered back to >95% for all cases and plans. All organs at risk (OAR) were spared with < 5% increase from original motion-free plans. Conclusion: Tomotherapy SBRT is less motion-impacted when 5cm dynamic jaw is used. Once the motion pattern is known, the jaw and MLC compensation program can largely minimize the compromised target coverage and OAR sparing.

  19. MO-FG-BRA-07: Intrafractional Motion Effect Can Be Minimized in Tomotherapy Stereotactic Body Radiotherapy (SBRT)

    International Nuclear Information System (INIS)

    Price, A; Chang, S; Matney, J; Wang, A; Lian, J; Chao, E

    2016-01-01

    Purpose: Tomotherapy has unique challenges in handling intrafractional motion compared to conventional LINAC. In this study, we analyzed the impact of intrafractional motion on cumulative dosimetry using actual patient motion data and investigated real time jaw/MLC compensation approaches to minimize the motion-induced dose discrepancy in Tomotherapy SBRT treatment. Methods: Intrafractional motion data recorded in two CyberKnife lung treatment cases through fiducial tracking and two LINAC prostate cases through Calypso tracking were used in this study. For each treatment site, one representative case has an average motion (6mm) and one has a large motion (10mm for lung and 15mm for prostate). The cases were re-planned on Tomotherapy for SBRT. Each case was planned with 3 different jaw settings: 1cm static, 2.5cm dynamic, and 5cm dynamic. 4D dose accumulation software was developed to compute dose with the recorded motions and theoretically compensate motions by modifying original jaw and MLC to track the trajectory of the tumor. Results: PTV coverage in Tomotherapy SBRT for patients with intrafractional motion depends on motion type, amplitude and plan settings. For the prostate patient with large motion, PTV coverage changed from 97.2% (motion-free) to 47.1% (target motion-included), 96.6% to 58.5% and 96.3% to 97.8% for the 1cm static jaw, 2.5cm dynamic jaw and 5cm dynamic jaw setting, respectively. For the lung patient with large motion, PTV coverage discrepancies showed a similar trend of change. When the jaw and MLC compensation program was engaged, the motion compromised PTV coverage was recovered back to >95% for all cases and plans. All organs at risk (OAR) were spared with < 5% increase from original motion-free plans. Conclusion: Tomotherapy SBRT is less motion-impacted when 5cm dynamic jaw is used. Once the motion pattern is known, the jaw and MLC compensation program can largely minimize the compromised target coverage and OAR sparing.

  20. Protection of quality and innovation in radiation oncology. The prospective multicenter trial QUIRO of DEGRO: evaluation of time, attendance of medical staff, and resources during radiotherapy with tomotherapy

    International Nuclear Information System (INIS)

    Winkler, Cornelia; Duma, M.N.; Molls, M.; Kampfer, S.; Popp, W.; Sack, H.; Budach, V.

    2014-01-01

    The technical progress in radiotherapy in recent years has been tremendous. This also implies a change of human and time resources. However, there is a lack of data on this topic. Therefore, the DEGRO initiated several studies in the QUIRO project on this subject. The present publication focuses on results for tomotherapy systems and compares them with other IMRT techniques. Over a period of several months, time allocation was documented using a standard form at two university hospitals. The required time for individual steps in the treatment planning process was recorded for all involved professional groups (physicist, technician, and physician) by themselves. The time monitoring at the treatment machines was performed by auxiliary employees (student research assistants). Evaluation of the data was performed for all recorded data as well as by tumor site. A comparison was made between the two involved institutions. A total of 1,691 records were analyzed: 148 from head and neck (H and N) tumors, 460 from prostate cancer, 136 from breast cancer, and 947 from other tumor entities. The mean value of all data from both centers for the definition of the target volumes for H and N tumors took a radiation oncology specialist 75 min, while a physicist needed for the physical treatment planning 214 min. For prostate carcinomas, the times were 60 and 147 min, respectively, and for the group of other entities 63 and 192 min, respectively. For the first radiation treatment, the occupancy time of the linear accelerator room was 31, 26, and 30 min for each entity (H and N, prostate, other entities, respectively). For routine treatments 22, 18, and 21 min were needed for the particular entities. Major differences in the time required for the individual steps were observed between the two centers. This study gives an overview of the time and personnel requirements in radiation therapy using a tomotherapy system. The most representative analysis could be done for the room occupancy

  1. Protection of quality and innovation in radiation oncology: the prospective multicenter trial QUIRO of DEGRO: evaluation of time, attendance of medical staff, and resources during radiotherapy with tomotherapy.

    Science.gov (United States)

    Winkler, Cornelia; Duma, M N; Popp, W; Sack, H; Budach, V; Molls, M; Kampfer, S

    2014-10-01

    The technical progress in radiotherapy in recent years has been tremendous. This also implies a change of human and time resources. However, there is a lack of data on this topic. Therefore, the DEGRO initiated several studies in the QUIRO project on this subject. The present publication focuses on results for tomotherapy systems and compares them with other IMRT techniques. Over a period of several months, time allocation was documented using a standard form at two university hospitals. The required time for individual steps in the treatment planning process was recorded for all involved professional groups (physicist, technician, and physician) by themselves. The time monitoring at the treatment machines was performed by auxiliary employees (student research assistants). Evaluation of the data was performed for all recorded data as well as by tumor site. A comparison was made between the two involved institutions. A total of 1,691 records were analyzed: 148 from head and neck (H&N) tumors, 460 from prostate cancer, 136 from breast cancer, and 947 from other tumor entities. The mean value of all data from both centers for the definition of the target volumes for H&N tumors took a radiation oncology specialist 75 min, while a physicist needed for the physical treatment planning 214 min. For prostate carcinomas, the times were 60 and 147 min, respectively, and for the group of other entities 63 and 192 min, respectively. For the first radiation treatment, the occupancy time of the linear accelerator room was 31, 26, and 30 min for each entity (H&N, prostate, other entities, respectively). For routine treatments 22, 18, and 21 min were needed for the particular entities. Major differences in the time required for the individual steps were observed between the two centers. This study gives an overview of the time and personnel requirements in radiation therapy using a tomotherapy system. The most representative analysis could be done for the room occupancy times

  2. Longitudinal assessment of parotid function in patients receiving tomotherapy for head-and-neck cancer

    International Nuclear Information System (INIS)

    Voordeckers, M.; Tournel, K.; Verellen, D.; Esch, G. van; Storme, G.; Everaert, H.; Vanhove, C.; Baron, I.

    2008-01-01

    Background and purpose: conventional radiotherapy is associated with high doses to the salivary glands which causes xerostomia and adverse effects on quality of life. The study aims to investigate the potential of helical tomotherapy (Hi-Art Tomotherapy registered ) to preserve parotid function in head-and-neck cancer patients. Patients and methods: seven consecutive patients treated with helical tomotherapy at the UZ Brussel, Belgium, were included. During planning, priority was attributed to planning target volume (PTV) coverage: ≥ 95% of the dose must be delivered to ≥ 95% of the PTV. Elective nodal regions received 54 Gy (1.8 Gy/fraction). A dose of 70.5 Gy (2.35 Gy/fraction) was prescribed to the primary tumor and pathologic lymph nodes = simultaneous integrated boost scheme. If possible, the mean parotid dose was kept below 26 Gy. Salivary gland function was assessed by technetium scintigraphy. Results: there was a significant dose-response relationship between mean parotid dose and functional recuperation. If the mean dose was kept 26 %). In order to preserve 75% of SE, 46% of the parotid volume should receive a dose 26 Gy can be reduced. (orig.)

  3. Feasibility and efficacy of helical intensity-modulated radiotherapy for stage III non-small cell lung cancer in comparison with conventionally fractionated 3D-CRT.

    Science.gov (United States)

    He, Jian; Huang, Yan; Chen, Yixing; Shi, Shiming; Ye, Luxi; Hu, Yong; Zhang, Jianying; Zeng, Zhaochong

    2016-05-01

    The standard treatment for stage III non-small-cell lung cancer (NSCLC) is still 60 Gy in conventional fractions combined with concurrent chemotherapy; however, the resulting local controls are disappointing. The aim of this study was to compare and assess the feasibility and efficacy of hypofractionated chemoradiotherapy using helical tomotherapy (HT) with conventional fractionation as opposed to using three-dimensional conformal radiotherapy (3D-CRT) for stage III NSCLC. Sixty-nine patients with stage III (AJCC 7th edition) NSCLC who underwent definitive radiation treatment at our institution between July 2011 and November 2013 were reviewed and analyzed retrospectively. A dose of 60 Gy in 20 fractions was delivered in the HT group (n=34), whereas 60 Gy in 30 fractions in the 3D-CRT group (n=35). Primary endpoints were toxicity, overall response rate, overall survival (OS) and progression-free survival (PFS). The median follow-up period was 26.4 months. V20 (P=0.005), V30 (P=0.001), V40 (P=0.004), mean lung dose (P=0.000) and max dose of spinal cord (P=0.005) were significantly lower in the HT group than in the 3D-CRT group. There was no significant difference in the incidences of acute radiation pneumonitis (RP) ≥ grade 2 between the two groups, whereas the incidences of acute radiation esophagitis ≥ grade 2 were significantly lower in the HT group than in the 3D-CRT group (P=0.027). Two-year overall response rate was significantly higher in the HT group than in the 3D-CRT group (P=0.015). One- and 2-year OS rates were significantly higher in the HT group (95.0% and 68.7%, respectively) than in the 3D-CRT group (85.5% and 47.6%, respectively; P=0.0236). One- and 2-year PFS rates were significantly higher in the HT group (57.8% and 26.3%, respectively) than in the 3D-CRT group (32.7% and 11.4%, respectively; P=0.0351). Univariate analysis indicated that performance status (PS), T stage and radiotherapy technique were significant prognostic factors for both OS

  4. Protection of quality and innovation in radiation oncology. The prospective multicenter trial QUIRO of DEGRO: evaluation of time, attendance of medical staff, and resources during radiotherapy with tomotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Winkler, Cornelia; Duma, M.N.; Molls, M.; Kampfer, S. [Technische Universitaet Muenchen, Department of Radiotherapy and Radiooncology, Klinikum rechts der Isar, Munich (Germany); Popp, W. [Prime Networks AG, Basel (Switzerland); Sack, H. [University of Essen, Department of Radiation Oncology, Essen (Germany); Budach, V. [Charite University Medicine, Department of Radiation Oncology, Berlin (Germany)

    2014-10-15

    The technical progress in radiotherapy in recent years has been tremendous. This also implies a change of human and time resources. However, there is a lack of data on this topic. Therefore, the DEGRO initiated several studies in the QUIRO project on this subject. The present publication focuses on results for tomotherapy systems and compares them with other IMRT techniques. Over a period of several months, time allocation was documented using a standard form at two university hospitals. The required time for individual steps in the treatment planning process was recorded for all involved professional groups (physicist, technician, and physician) by themselves. The time monitoring at the treatment machines was performed by auxiliary employees (student research assistants). Evaluation of the data was performed for all recorded data as well as by tumor site. A comparison was made between the two involved institutions. A total of 1,691 records were analyzed: 148 from head and neck (H and N) tumors, 460 from prostate cancer, 136 from breast cancer, and 947 from other tumor entities. The mean value of all data from both centers for the definition of the target volumes for H and N tumors took a radiation oncology specialist 75 min, while a physicist needed for the physical treatment planning 214 min. For prostate carcinomas, the times were 60 and 147 min, respectively, and for the group of other entities 63 and 192 min, respectively. For the first radiation treatment, the occupancy time of the linear accelerator room was 31, 26, and 30 min for each entity (H and N, prostate, other entities, respectively). For routine treatments 22, 18, and 21 min were needed for the particular entities. Major differences in the time required for the individual steps were observed between the two centers. This study gives an overview of the time and personnel requirements in radiation therapy using a tomotherapy system. The most representative analysis could be done for the room occupancy

  5. Comparison study of the partial-breast irradiation techniques: Dosimetric analysis of three-dimensional conformal radiation therapy, electron beam therapy, and helical tomotherapy depending on various tumor locations

    International Nuclear Information System (INIS)

    Kim, Min-Joo; Park, So-Hyun; Son, Seok-Hyun; Cheon, Keum-Seong; Choi, Byung-Ock; Suh, Tae-Suk

    2013-01-01

    The partial-breast irradiation (PBI) technique, an alternative to whole-breast irradiation, is a beam delivery method that uses a limited range of treatment volume. The present study was designed to determine the optimal PBI treatment modalities for 8 different tumor locations. Treatment planning was performed on computed tomography (CT) data sets of 6 patients who had received lumpectomy treatments. Tumor locations were classified into 8 subsections according to breast quadrant and depth. Three-dimensional conformal radiation therapy (3D-CRT), electron beam therapy (ET), and helical tomotherapy (H-TOMO) were utilized to evaluate the dosimetric effect for each tumor location. Conformation number (CN), radical dose homogeneity index (rDHI), and dose delivered to healthy tissue were estimated. The Kruskal-Wallis, Mann-Whitney U, and Bonferroni tests were used for statistical analysis. The ET approach showed good sparing effects and acceptable target coverage for the lower inner quadrant—superficial (LIQ-S) and lower inner quadrant—deep (LIQ-D) locations. The H-TOMO method was the least effective technique as no evaluation index achieved superiority for all tumor locations except CN. The ET method is advisable for treating LIQ-S and LIQ-D tumors, as opposed to 3D-CRT or H-TOMO, because of acceptable target coverage and much lower dose applied to surrounding tissue

  6. PET-guided dose escalation tomotherapy in malignant pleural mesothelioma

    Energy Technology Data Exchange (ETDEWEB)

    Fodor, Andrei; Dell' Oca, Italo; Pasetti, Marcella; Di Muzio, Nadia Gisella [San Raffaele Scientific Institute, Milan (Italy). Dept. of Radiotherapy; Fiorino, Claudio; Broggi, Sara; Cattaneo, Giovanni Mauro; Calandrino, Riccardo [San Raffaele Scientific Institute, Milan (Italy). Medical Physics; Gianolli, Luigi [San Raffaele Scientific Institute, Milan (Italy). Dept. of Nuclear Medicine

    2011-11-15

    To test the feasibility of salvage radiotherapy using PET-guided helical tomotherapy in patients with progressive malignant pleural mesothelioma (MPM). A group of 12 consecutive MPM patients was treated with 56 Gy/25 fractions to the planning target volume (PTV); FDG-PET/CT simulation was always performed to include all positive lymph nodes and MPM infiltrations. Subsequently, a second group of 12 consecutive patients was treated with the same dose to the whole pleura adding a simultaneous integrated boost of 62.5 Gy to the FDG-PET/CT positive areas (BTV). Good dosimetric results were obtained in both groups. No grade 3 (RTOG/EORTC) acute or late toxicities were reported in the first group, while 3 cases of grade 3 late pneumonitis were registered in the second group: the duration of symptoms was 2-10 weeks. Median overall survival was 8 months (1.2-50.5 months) and 20 months (4.3-33.8 months) from the beginning of radiotherapy, for groups I and II, respectively (p = 0.19). A significant impact on local relapse from radiotherapy was seen (median time to local relapse: 8 vs 17 months; 1-year local relapse-free rate: 16% vs 81%, p = 0.003). The results of this pilot study support the planning of a phase III study of combined sequential chemoradiotherapy with dose escalation to BTV in patients not able to undergo resection. (orig.)

  7. Multi-institutional Feasibility Study of a Fast Patient Localization Method in Total Marrow Irradiation With Helical Tomotherapy: A Global Health Initiative by the International Consortium of Total Marrow Irradiation

    International Nuclear Information System (INIS)

    Takahashi, Yutaka; Vagge, Stefano; Agostinelli, Stefano; Han, Eunyoung; Matulewicz, Lukasz; Schubert, Kai; Chityala, Ravishankar; Ratanatharathorn, Vaneerat; Tournel, Koen; Penagaricano, Jose A.; Florian, Sterzing; Mahe, Marc-Andre; Verneris, Michael R.; Weisdorf, Daniel J.

    2015-01-01

    Purpose: To develop, characterize, and implement a fast patient localization method for total marrow irradiation. Methods and Materials: Topographic images were acquired using megavoltage computed tomography (MVCT) detector data by delivering static orthogonal beams while the couch traversed through the gantry. Geometric and detector response corrections were performed to generate a megavoltage topogram (MVtopo). We also generated kilovoltage topograms (kVtopo) from the projection data of 3-dimensional CT images to reproduce the same geometry as helical tomotherapy. The MVtopo imaging dose and the optimal image acquisition parameters were investigated. A multi-institutional phantom study was performed to verify the image registration uncertainty. Forty-five MVtopo images were acquired and analyzed with in-house image registration software. Results: The smallest jaw size (front and backup jaws of 0) provided the best image contrast and longitudinal resolution. Couch velocity did not affect the image quality or geometric accuracy. The MVtopo dose was less than the MVCT dose. The image registration uncertainty from the multi-institutional study was within 2.8 mm. In patient localization, the differences in calculated couch shift between the registration with MVtopo-kVtopo and MVCT-kVCT images in lateral, cranial–caudal, and vertical directions were 2.2 ± 1.7 mm, 2.6 ± 1.4 mm, and 2.7 ± 1.1 mm, respectively. The imaging time in MVtopo acquisition at the couch speed of 3 cm/s was <1 minute, compared with ≥15 minutes in MVCT for all patients. Conclusion: Whole-body MVtopo imaging could be an effective alternative to time-consuming MVCT for total marrow irradiation patient localization

  8. SU-E-T-417: The Impact of Normal Tissue Constraints On PTV Dose Homogeneity for Intensity Modulated Radiotherapy (IMRT), Volume Modulated Arc Therapy (VMAT) and Tomotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Peng, J; McDonald, D; Ashenafi, M; Ellis, A; Vanek, K [Medical University of South Carolina, Charleston, SC (United States)

    2014-06-01

    Purpose: Complex intensity modulated arc therapy tends to spread low dose to normal tissue(NT)regions to obtain improved target conformity and homogeneity and OAR sparing.This work evaluates the trade-offs between PTV homogeneity and reduction of the maximum dose(Dmax)spread to NT while planning of IMRT,VMAT and Tomotherapy. Methods: Ten prostate patients,previously planned with step-and-shoot IMRT,were selected.To fairly evaluate how PTV homogeneity was affected by NT Dmax constraints,original IMRT DVH objectives for PTV and OARs(femoral heads,and rectal and bladder wall)applied to 2 VMAT plans in Pinnacle(V9.0), and Tomotherapy(V4.2).The only constraint difference was the NT which was defined as body contours excluding targets,OARs and dose rings.NT Dmax constraint for 1st VMAT was set to the prescription dose(Dp).For 2nd VMAT(VMAT-NT)and Tomotherapy,it was set to the Dmax achieved in IMRT(~70-80% of Dp).All NT constraints were set to the lowest priority.Three common homogeneity indices(HI),RTOG-HI=Dmax/Dp,moderated-HI=D95%/D5% and complex-HI=(D2%-D98%)/Dp*100 were calculated. Results: All modalities with similar dosimetric endpoints for PTV and OARs.The complex-HI shows the most variability of indices,with average values of 5.9,4.9,9.3 and 6.1 for IMRT,VMAT,VMAT-NT and Tomotherapy,respectively.VMAT provided the best PTV homogeneity without compromising any OAR/NT sparing.Both VMAT-NT and Tomotherapy,planned with more restrictive NT constraints,showed reduced homogeneity,with VMAT-NT showing the worst homogeneity(P<0.0001)for all HI.Tomotherapy gave the lowest NT Dmax,with slightly decreased homogeneity compared to VMAT. Finally, there was no significant difference in NT Dmax or Dmean between VMAT and VMAT-NT. Conclusion: PTV HI is highly dependent on permitted NT constraints. Results demonstrated that VMAT-NT with more restrictive NT constraints does not reduce Dmax NT,but significantly receives higher Dmax and worse target homogeneity.Therefore, it is critical

  9. Whole brain radiotherapy with adjuvant or concomitant boost in brain metastasis: dosimetric comparison between helical and volumetric IMRT technique.

    Science.gov (United States)

    Borghetti, Paolo; Pedretti, Sara; Spiazzi, Luigi; Avitabile, Rossella; Urpis, Mauro; Foscarini, Federica; Tesini, Giulia; Trevisan, Francesca; Ghirardelli, Paolo; Pandini, Sara Angela; Triggiani, Luca; Magrini, Stefano Maria; Buglione, Michela

    2016-04-19

    To compare and evaluate the possible advantages related to the use of VMAT and helical IMRT and two different modalities of boost delivering, adjuvant stereotactic boost (SRS) or simultaneous integrated boost (SIB), in the treatment of brain metastasis (BM) in RPA classes I-II patients. Ten patients were treated with helical IMRT, 5 of them with SRS after whole brain radiotherapy (WBRT) and 5 with SIB. MRI co-registration with planning CT was mandatory and prescribed doses were 30 Gy in 10 fractions (fr) for WBRT and 15Gy/1fr or 45Gy/10fr in SRS or SIB, respectively. For each patient, 4 "treatment plans" (VMAT SRS and SIB, helical IMRT SRS and SIB) were calculated and accepted if PTV boost was included in 95 % isodose and dose constraints of the main organs at risk were respected without major deviations. Homogeneity Index (HI), Conformal Index (CI) and Conformal Number (CN) were considered to compare the different plans. Moreover, time of treatment delivery was calculated and considered in the analysis. Volume of brain metastasis ranged between 1.43 and 51.01 cc (mean 12.89 ± 6.37 ml) and 3 patients had double lesions. V95% resulted over 95 % in the average for each kind of technique, but the "target coverage" was inadequate for VMAT planning with two sites. The HI resulted close to the ideal value of zero in all cases; VMAT-SIB, VMAT-SRS, Helical IMRT-SIB and Helical IMRT-SRS showed mean CI of 2.15, 2.10, 2.44 and 1.66, respectively (optimal range: 1.5-2.0). Helical IMRT-SRS was related to the best and reliable finding of CN (0.66). The mean of treatment time was 210 s, 467 s, 440 s, 1598 s, respectively, for VMAT-SIB, VMAT-SRS, Helical IMRT-SIB and Helical IMRT-SRS. This dosimetric comparison show that helical IMRT obtain better target coverage and respect of CI and CN; VMAT could be acceptable in solitary metastasis. SIB modality can be considered as a good choice for clinical and logistic compliance; literature's preliminary data are confirming also a

  10. Whole brain radiotherapy with adjuvant or concomitant boost in brain metastasis: dosimetric comparison between helical and volumetric IMRT technique

    International Nuclear Information System (INIS)

    Borghetti, Paolo; Pedretti, Sara; Spiazzi, Luigi; Avitabile, Rossella; Urpis, Mauro; Foscarini, Federica; Tesini, Giulia; Trevisan, Francesca; Ghirardelli, Paolo; Pandini, Sara Angela; Triggiani, Luca; Magrini, Stefano Maria; Buglione, Michela

    2016-01-01

    To compare and evaluate the possible advantages related to the use of VMAT and helical IMRT and two different modalities of boost delivering, adjuvant stereotactic boost (SRS) or simultaneous integrated boost (SIB), in the treatment of brain metastasis (BM) in RPA classes I-II patients. Ten patients were treated with helical IMRT, 5 of them with SRS after whole brain radiotherapy (WBRT) and 5 with SIB. MRI co-registration with planning CT was mandatory and prescribed doses were 30 Gy in 10 fractions (fr) for WBRT and 15Gy/1fr or 45Gy/10fr in SRS or SIB, respectively. For each patient, 4 “treatment plans” (VMAT SRS and SIB, helical IMRT SRS and SIB) were calculated and accepted if PTV boost was included in 95 % isodose and dose constraints of the main organs at risk were respected without major deviations. Homogeneity Index (HI), Conformal Index (CI) and Conformal Number (CN) were considered to compare the different plans. Moreover, time of treatment delivery was calculated and considered in the analysis. Volume of brain metastasis ranged between 1.43 and 51.01 cc (mean 12.89 ± 6.37 ml) and 3 patients had double lesions. V95% resulted over 95 % in the average for each kind of technique, but the “target coverage” was inadequate for VMAT planning with two sites. The HI resulted close to the ideal value of zero in all cases; VMAT-SIB, VMAT-SRS, Helical IMRT-SIB and Helical IMRT-SRS showed mean CI of 2.15, 2.10, 2.44 and 1.66, respectively (optimal range: 1.5–2.0). Helical IMRT-SRS was related to the best and reliable finding of CN (0.66). The mean of treatment time was 210 s, 467 s, 440 s, 1598 s, respectively, for VMAT-SIB, VMAT-SRS, Helical IMRT-SIB and Helical IMRT-SRS. This dosimetric comparison show that helical IMRT obtain better target coverage and respect of CI and CN; VMAT could be acceptable in solitary metastasis. SIB modality can be considered as a good choice for clinical and logistic compliance; literature’s preliminary data are confirming

  11. Use of semiconductor diodes for dosimetry TomoTherapy Hi-Art unit; Utilizacion de diodos de semiconductor para la dosimetria de una unidad Tomotherapy Hi-Art

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez Rodriguez, J.; Garcia Repiso, S.; Martin Rincon, C.; Ramos Pacho, J. A.; Verde Velasco, J. M.; Montes Fuentes, C.; Dena Espinel, E. de; Gomez Llorente, P. L.; Fernandez Bordes, M.

    2011-07-01

    The radiotherapy unit TIT-Art TomoTherapy allows the realization of intensity modulated treatments in a helical manner through design, consisting of a linear accelerator installed on a rotating gantry in combination with the longitudinal movement of the treatment table and a multi leaf collimator (MLC) binary. The acceptance tests include, among other things, the acquisition of a set of dosimetric data (profiles and PDD), for later comparison with a reference set of measures taken at the factory, called the gold standard. Being pre commissioning from the factory, the unit will be accepted provided that the measured data meet the gold standard within preset tolerances. The dosimetric equipment used in the test of acceptance is provided by the manufacturer and so far is done with water tank, camera, software electrometer and associate of Standard Imaging and marketed by TomoTherapy Inc. The objective of this study is to compare the measures obtained with a semiconductor diode with the gold standard. (Author)

  12. Actual Dose Variation of Parotid Glands and Spinal Cord for Nasopharyngeal Cancer Patients During Radiotherapy

    International Nuclear Information System (INIS)

    Han Chunhui; Chen Yijen; Liu An; Schultheiss, Timothy E.; Wong, Jeffrey Y.C.

    2008-01-01

    Purpose: For intensity-modulated radiotherapy of nasopharyngeal cancer, accurate dose delivery is crucial to the success of treatment. This study aimed to evaluate the significance of daily image-guided patient setup corrections and to quantify the parotid gland volume and dose variations for nasopharyngeal cancer patients using helical tomotherapy megavoltage computed tomography (CT). Methods and Materials: Five nasopharyngeal cancer patients who underwent helical tomotherapy were selected retrospectively. Each patient had received 70 Gy in 35 fractions. Daily megavoltage CT scans were registered with the planning CT images to correct the patient setup errors. Contours of the spinal cord and parotid glands were drawn on the megavoltage CT images at fixed treatment intervals. The actual doses delivered to the critical structures were calculated using the helical tomotherapy Planned Adaptive application. Results: The maximal dose to the spinal cord showed a significant increase and greater variation without daily setup corrections. The significant decrease in the parotid gland volume led to a greater median dose in the later phase of treatment. The average parotid gland volume had decreased from 20.5 to 13.2 cm 3 by the end of treatment. On average, the median dose to the parotid glands was 83 cGy and 145 cGy for the first and the last treatment fractions, respectively. Conclusions: Daily image-guided setup corrections can eliminate significant dose variations to critical structures. Constant monitoring of patient anatomic changes and selective replanning should be used during radiotherapy to avoid critical structure complications

  13. Use of semiconductor diodes for dosimetry TomoTherapy Hi-Art unit

    International Nuclear Information System (INIS)

    Hernandez Rodriguez, J.; Garcia Repiso, S.; Martin Rincon, C.; Ramos Pacho, J. A.; Verde Velasco, J. M.; Montes Fuentes, C.; Dena Espinel, E. de; Gomez Llorente, P. L.; Fernandez Bordes, M.

    2011-01-01

    The radiotherapy unit TIT-Art TomoTherapy allows the realization of intensity modulated treatments in a helical manner through design, consisting of a linear accelerator installed on a rotating gantry in combination with the longitudinal movement of the treatment table and a multi leaf collimator (MLC) binary. The acceptance tests include, among other things, the acquisition of a set of dosimetric data (profiles and PDD), for later comparison with a reference set of measures taken at the factory, called the gold standard. Being pre commissioning from the factory, the unit will be accepted provided that the measured data meet the gold standard within preset tolerances. The dosimetric equipment used in the test of acceptance is provided by the manufacturer and so far is done with water tank, camera, software electrometer and associate of Standard Imaging and marketed by TomoTherapy Inc. The objective of this study is to compare the measures obtained with a semiconductor diode with the gold standard. (Author)

  14. ARCHERRT - a GPU-based and photon-electron coupled Monte Carlo dose computing engine for radiation therapy: software development and application to helical tomotherapy.

    Science.gov (United States)

    Su, Lin; Yang, Youming; Bednarz, Bryan; Sterpin, Edmond; Du, Xining; Liu, Tianyu; Ji, Wei; Xu, X George

    2014-07-01

    performed inferior to the original one. ARCHERRT achieves a fast speed for PSF-based dose calculations. With a single M2090 card, the simulations cost about 60, 50, 80 s for three cases, respectively, with the 1% statistical error in the PTV. Using the latest K40 card, the simulations are 1.7-1.8 times faster. More impressively, six M2090 cards could finish the simulations in 8.9-13.4 s. For comparison, the same simulations on Intel E5-2620 (12 hyperthreading) cost about 500-800 s. ARCHERRT was developed successfully to perform fast and accurate MC dose calculation for radiotherapy using PSFs and patient CT phantoms.

  15. ARCHERRT – A GPU-based and photon-electron coupled Monte Carlo dose computing engine for radiation therapy: Software development and application to helical tomotherapy

    Science.gov (United States)

    Su, Lin; Yang, Youming; Bednarz, Bryan; Sterpin, Edmond; Du, Xining; Liu, Tianyu; Ji, Wei; Xu, X. George

    2014-01-01

    Woodcock tracking algorithm performed inferior to the original one. ARCHERRT achieves a fast speed for PSF-based dose calculations. With a single M2090 card, the simulations cost about 60, 50, 80 s for three cases, respectively, with the 1% statistical error in the PTV. Using the latest K40 card, the simulations are 1.7–1.8 times faster. More impressively, six M2090 cards could finish the simulations in 8.9–13.4 s. For comparison, the same simulations on Intel E5-2620 (12 hyperthreading) cost about 500–800 s. Conclusions: ARCHERRT was developed successfully to perform fast and accurate MC dose calculation for radiotherapy using PSFs and patient CT phantoms. PMID:24989378

  16. ARCHERRT – A GPU-based and photon-electron coupled Monte Carlo dose computing engine for radiation therapy: Software development and application to helical tomotherapy

    International Nuclear Information System (INIS)

    Su, Lin; Du, Xining; Liu, Tianyu; Ji, Wei; Xu, X. George; Yang, Youming; Bednarz, Bryan; Sterpin, Edmond

    2014-01-01

    , modified Woodcock tracking algorithm performed inferior to the original one. ARCHER RT achieves a fast speed for PSF-based dose calculations. With a single M2090 card, the simulations cost about 60, 50, 80 s for three cases, respectively, with the 1% statistical error in the PTV. Using the latest K40 card, the simulations are 1.7–1.8 times faster. More impressively, six M2090 cards could finish the simulations in 8.9–13.4 s. For comparison, the same simulations on Intel E5-2620 (12 hyperthreading) cost about 500–800 s. Conclusions: ARCHER RT was developed successfully to perform fast and accurate MC dose calculation for radiotherapy using PSFs and patient CT phantoms

  17. A Comparison of Helical Intensity-Modulated Radiotherapy, Intensity-Modulated Radiotherapy, and 3D-Conformal Radiation Therapy for Pancreatic Cancer

    International Nuclear Information System (INIS)

    Poppe, Matthew M.; Narra, Venkat; Yue, Ning J.; Zhou Jinghao; Nelson, Carl; Jabbour, Salma K.

    2011-01-01

    We assessed dosimetric differences in pancreatic cancer radiotherapy via helical intensity-modulated radiotherapy (HIMRT), linac-based IMRT, and 3D-conformal radiation therapy (3D-CRT) with regard to successful plan acceptance and dose to critical organs. Dosimetric analysis was performed in 16 pancreatic cases that were planned to 54 Gy; both post-pancreaticoduodenectomy (n = 8) and unresected (n = 8) cases were compared. Without volume modification, plans met constraints 75% of the time with HIMRT and IMRT and 13% with 3D-CRT. There was no statistically significantly improvement with HIMRT over conventional IMRT in reducing liver V35, stomach V45, or bowel V45. HIMRT offers improved planning target volume (PTV) dose homogeneity compared with IMRT, averaging a lower maximum dose and higher volume receiving the prescription dose (D100). HIMRT showed an increased mean dose over IMRT to bowel and liver. Both HIMRT and IMRT offer a statistically significant improvement over 3D-CRT in lowering dose to liver, stomach, and bowel. The results were similar for both unresected and resected patients. In pancreatic cancer, HIMRT offers improved dose homogeneity over conventional IMRT and several significant benefits to 3D-CRT. Factors to consider before incorporating IMRT into pancreatic cancer therapy are respiratory motion, dose inhomogeneity, and mean dose.

  18. Daily measure of the constancy of rotation in the evaluation of geometric and dosimetric parameters of the tomotherapy

    International Nuclear Information System (INIS)

    Erzilbengoa, M.; Moral, S.; Bragado, L.; Guisasola, M. A.

    2011-01-01

    The daily test performance called ''Rotating Constancia'', based on the methodology developed by Balog ''Helical tomotherapy dynamic quality assurance'' (2006), has allowed us over these 2 years to assess the response to TomoTherapy machine parameters given dose, travel speed table offset of the same, position of the green lasers, field size, rotation time and energy index of the beam parameters can be measured without intensity modulation.

  19. Application of failure mode and effects analysis (FMEA) to pretreatment phases in tomotherapy.

    Science.gov (United States)

    Broggi, Sara; Cantone, Marie Claire; Chiara, Anna; Di Muzio, Nadia; Longobardi, Barbara; Mangili, Paola; Veronese, Ivan

    2013-09-06

    The aim of this paper was the application of the failure mode and effects analysis (FMEA) approach to assess the risks for patients undergoing radiotherapy treatments performed by means of a helical tomotherapy unit. FMEA was applied to the preplanning imaging, volume determination, and treatment planning stages of the tomotherapy process and consisted of three steps: 1) identification of the involved subprocesses; 2) identification and ranking of the potential failure modes, together with their causes and effects, using the risk probability number (RPN) scoring system; and 3) identification of additional safety measures to be proposed for process quality and safety improvement. RPN upper threshold for little concern of risk was set at 125. A total of 74 failure modes were identified: 38 in the stage of preplanning imaging and volume determination, and 36 in the stage of planning. The threshold of 125 for RPN was exceeded in four cases: one case only in the phase of preplanning imaging and volume determination, and three cases in the stage of planning. The most critical failures appeared related to (i) the wrong or missing definition and contouring of the overlapping regions, (ii) the wrong assignment of the overlap priority to each anatomical structure, (iii) the wrong choice of the computed tomography calibration curve for dose calculation, and (iv) the wrong (or not performed) choice of the number of fractions in the planning station. On the basis of these findings, in addition to the safety strategies already adopted in the clinical practice, novel solutions have been proposed for mitigating the risk of these failures and to increase patient safety.

  20. Conformal radiotherapy by intensity modulation of pediatrics tumors

    International Nuclear Information System (INIS)

    Leseur, J.; Le Prise, E.; Carrie, C.; Bernier, V.; Beneyton, V.; Mahe, M.A.; Supiot, S.

    2009-01-01

    The objective of this study is to take stock on the validated and potential indications of the conformal radiotherapy with intensity modulation ( intensity modulated radiotherapy I.M.R.T.) in pediatrics and to propose recommendations for its use as well as the adapted dose constraints. About 40 to 50% of children treated for a cancer are irradiated. The I.M.R.T., by linear accelerator or helical tomo-therapy has for aim to give a homogenous dose to the target volume and to save organs at risk. Its use in pediatrics seems particularly interesting because of the complexity of target volumes and the closeness of organs at risk. In compensation for these positive elements, the importance of low doses irradiation given in big volumes makes fear event consequences on growth and an increased incidence of secondary cancers in children suffering from tumors with high cure rates and long life expectancy. (N.C.)

  1. Conformal radiotherapy by intensity modulation of pediatrics tumors; Radiotherapie conformationnelle par modulation d'intensite des tumeurs pediatriques

    Energy Technology Data Exchange (ETDEWEB)

    Leseur, J.; Le Prise, E. [Centre Eugene-Marquis, 35 - Rennes (France); Carrie, C. [Centre Leon Berard, 69 - Lyon (France); Bernier, V. [Centre Alexis-Vautrin, 54 - Nancy (France); Beneyton, V. [Centre Paul-Strauss, 67 - Strasbourg (France); Mahe, M.A.; Supiot, S. [Centre Rene-Gauducheau, 44 - Nantes (France)

    2009-10-15

    The objective of this study is to take stock on the validated and potential indications of the conformal radiotherapy with intensity modulation ( intensity modulated radiotherapy I.M.R.T.) in pediatrics and to propose recommendations for its use as well as the adapted dose constraints. About 40 to 50% of children treated for a cancer are irradiated. The I.M.R.T., by linear accelerator or helical tomo-therapy has for aim to give a homogenous dose to the target volume and to save organs at risk. Its use in pediatrics seems particularly interesting because of the complexity of target volumes and the closeness of organs at risk. In compensation for these positive elements, the importance of low doses irradiation given in big volumes makes fear event consequences on growth and an increased incidence of secondary cancers in children suffering from tumors with high cure rates and long life expectancy. (N.C.)

  2. Adaptive Radiotherapy Planning on Decreasing Gross Tumor Volumes as Seen on Megavoltage Computed Tomography Images

    International Nuclear Information System (INIS)

    Woodford, Curtis; Yartsev, Slav; Dar, A. Rashid; Bauman, Glenn; Van Dyk, Jake

    2007-01-01

    Purpose: To evaluate gross tumor volume (GTV) changes for patients with non-small-cell lung cancer by using daily megavoltage (MV) computed tomography (CT) studies acquired before each treatment fraction on helical tomotherapy and to relate the potential benefit of adaptive image-guided radiotherapy to changes in GTV. Methods and Materials: Seventeen patients were prescribed 30 fractions of radiotherapy on helical tomotherapy for non-small-cell lung cancer at London Regional Cancer Program from Dec 2005 to March 2007. The GTV was contoured on the daily MVCT studies of each patient. Adapted plans were created using merged MVCT-kilovoltage CT image sets to investigate the advantages of replanning for patients with differing GTV regression characteristics. Results: Average GTV change observed over 30 fractions was -38%, ranging from -12 to -87%. No significant correlation was observed between GTV change and patient's physical or tumor features. Patterns of GTV changes in the 17 patients could be divided broadly into three groups with distinctive potential for benefit from adaptive planning. Conclusions: Changes in GTV are difficult to predict quantitatively based on patient or tumor characteristics. If changes occur, there are points in time during the treatment course when it may be appropriate to adapt the plan to improve sparing of normal tissues. If GTV decreases by greater than 30% at any point in the first 20 fractions of treatment, adaptive planning is appropriate to further improve the therapeutic ratio

  3. Evaluation of two tomotherapy-based techniques for the delivery of whole-breast intensity-modulated radiation therapy

    International Nuclear Information System (INIS)

    Gonzalez, Victor J.; Buchholz, Daniel J.; Langen, Katja M.; Olivera, Gustavo H.; Chauhan, Bhavin; Meeks, Sanford L.; Ruchala, Kenneth J.; Haimerl, Jason; Lu Weiguo; Kupelian, Patrick A.

    2006-01-01

    Purpose: To evaluate two different techniques for whole-breast treatments delivered using the Hi-ART II tomotherapy device. Methods and Materials: Tomotherapy uses the standard rotational helical delivery. Topotherapy uses a stationary gantry while delivering intensity-modulated treatments. CT scans from 5 breast cancer patients were used. The prescription dose was 50.4 Gy. Results: On average, 99% of the target volume received 95% of prescribed dose with either technique. If treatment times are restricted to less than 9 min, the average percentage ipsilateral lung receiving ≥20 Gy was 22% for tomotherapy vs. 10% for topotherapy. The ipsilateral lung receiving ≥50.4 Gy was 4 cc for tomotherapy vs. 27 cc for topotherapy. The percentage of left ventricle receiving ≥30 Gy was 14% with tomotherapy vs. 4% for topotherapy. The average doses to the contralateral breast and lung were 0.6 and 0.8 Gy, respectively, for tomotherapy vs. 0.4 and 0.3 Gy for topotherapy. Conclusions: Tomotherapy provides improved target dose homogeneity and conformality over topotherapy. If delivery times are restricted, topotherapy reduces the amount of heart and ipsilateral lung volumes receiving low doses. For whole-breast treatments, topotherapy is an efficient technique that achieves adequate target uniformity while maintaining low doses to sensitive structures

  4. Analytical model of the binary multileaf collimator of tomotherapy for Monte Carlo simulations

    International Nuclear Information System (INIS)

    Sterpin, E; Vynckier, S; Salvat, F; Olivera, G H

    2008-01-01

    Helical Tomotherapy (HT) delivers intensity-modulated radiotherapy by the means of many configurations of the binary multi-leaf collimator (MLC). The aim of the present study was to devise a method, which we call the 'transfer function' (TF) method, to perform the transport of particles through the MLC much faster than the time consuming Monte Carlo (MC) simulation and with no significant loss of accuracy. The TF method consists of calculating, for each photon in the phase-space file, the attenuation factor for each leaf (up to three) that the photon passes, assuming straight propagation through closed leaves, and storing these factors in a modified phase-space file. To account for the transport through the MLC in a given configuration, the weight of a photon is simply multiplied by the attenuation factors of the leaves that are intersected by the photon ray and are closed. The TF method was combined with the PENELOPE MC code, and validated with measurements for the three static field sizes available (40x5, 40x2.5 and 40x1 cm 2 ) and for some MLC patterns. The TF method allows a large reduction in computation time, without introducing appreciable deviations from the result of full MC simulations

  5. Dosimetric Study of Current Treatment Options for Radiotherapy in Retinoblastoma

    Energy Technology Data Exchange (ETDEWEB)

    Eldebawy, Eman [Department of Radiation Oncology, McGill University Health Centre, Montreal, Quebec (Canada); Department of Radiation Oncology, Children' s Cancer Hospital, Cairo (Egypt); Parker, William, E-mail: william.parker@mcgill.ca [Department of Medical Physics, McGill University Health Centre, Montreal, Quebec (Canada); Abdel Rahman, Wamied [Department of Medical Physics, McGill University Health Centre, Montreal, Quebec (Canada); Freeman, Carolyn R. [Department of Radiation Oncology, McGill University Health Centre, Montreal, Quebec (Canada)

    2012-03-01

    Purpose: To determine the best treatment technique for patients with retinoblastoma requiring radiotherapy to the whole eye. Methods and Materials: Treatment plans for 3 patients with retinoblastoma were developed using 10 radiotherapy techniques including electron beams, photon beam wedge pair (WP), photon beam three-dimensional conformal radiotherapy (3D-CRT), fixed gantry intensity-modulated radiotherapy (IMRT), photon volumetric arc therapy (VMAT), fractionated stereotactic radiotherapy, and helical tomotherapy (HT). Dose-volume analyses were carried out for each technique. Results: All techniques provided similar target coverage; conformity was highest for VMAT, nine-field (9F) IMRT, and HT (conformity index [CI] = 1.3) and lowest for the WP and two electron techniques (CI = 1.8). The electron techniques had the highest planning target volume dose gradient (131% of maximum dose received [D{sub max}]), and the CRT techniques had the lowest (103% D{sub max}) gradient. The volume receiving at least 20 Gy (V{sub 20Gy}) for the ipsilateral bony orbit was lowest for the VMAT and HT techniques (56%) and highest for the CRT techniques (90%). Generally, the electron beam techniques were superior in terms of brain sparing and delivered approximately one-third of the integral dose of the photon techniques. Conclusions: Inverse planned image-guided radiotherapy delivered using HT or VMAT gives better conformity index, improved orbital bone and brain sparing, and a lower integral dose than other techniques.

  6. Analysis of daily quality assurance tests for tomotherapy and two Varian linear accelerators - three months review

    International Nuclear Information System (INIS)

    Kushwaha, Pratishtha; Jaiswal, Deeksha; Dheera, A.; Upreti, Udita; Chaudhari, Suresh; Kinhikar, Rajesh; Deshpande, Deepak; Shrivastava, Shyam

    2016-01-01

    Daily quality assurance (QA) for high precision radiotherapy equipments is very important to maintain the mechanical and dosimetric accuracy for patient treatments. Gross deviations in these parameters may have an adverse impact on the delivery of the treatments to patients. We report the results of daily QA tests performed over a period of three months for two Varian linear accelerators and a Tomotherapy machine

  7. Modelling simple helically delivered dose distributions

    International Nuclear Information System (INIS)

    Fenwick, John D; Tome, Wolfgang A; Kissick, Michael W; Mackie, T Rock

    2005-01-01

    In a previous paper, we described quality assurance procedures for Hi-Art helical tomotherapy machines. Here, we develop further some ideas discussed briefly in that paper. Simple helically generated dose distributions are modelled, and relationships between these dose distributions and underlying characteristics of Hi-Art treatment systems are elucidated. In particular, we describe the dependence of dose levels along the central axis of a cylinder aligned coaxially with a Hi-Art machine on fan beam width, couch velocity and helical delivery lengths. The impact on these dose levels of angular variations in gantry speed or output per linear accelerator pulse is also explored

  8. Intensity modulated conformal radiotherapy

    International Nuclear Information System (INIS)

    Noel, Georges; Moty-Monnereau, Celine; Meyer, Aurelia; David, Pauline; Pages, Frederique; Muller, Felix; Lee-Robin, Sun Hae; David, Denis Jean

    2006-12-01

    This publication reports the assessment of intensity-modulated conformal radiotherapy (IMCR). This assessment is based on a literature survey which focussed on indications, efficiency and safety on the short term, on the risk of radio-induced cancer on the long term, on the role in the therapeutic strategy, on the conditions of execution, on the impact on morbidity-mortality and life quality, on the impact on the health system and on public health policies and program. This assessment is also based on the opinion of a group of experts regarding the technical benefit of IMCR, its indications depending on the cancer type, safety in terms of radio-induced cancers, and conditions of execution. Before this assessment, the report thus indicates indications for which the use of IMCR can be considered as sufficient or not determined. It also proposes a technical description of IMCR and helical tomo-therapy, discusses the use of this technique for various pathologies or tumours, analyses the present situation of care in France, and comments the identification of this technique in foreign classifications

  9. 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

  10. MOSFET detectors in quality assurance of tomotherapy treatments.

    Science.gov (United States)

    Cherpak, Amanda; Studinski, Ryan C N; Cygler, Joanna E

    2008-02-01

    The purpose of this work was to characterize metal oxide semiconductor field-effect transistors (MOSFETs) in a 6 MV conventional linac and investigate their use for quality assurance of radiotherapy treatments with a tomotherapy Hi-Art unit. High sensitivity and standard sensitivity MOSFETs were first calibrated and then tested for reproducibility, field size dependence, and accuracy of measuring surface dose in a 6 MV beam as well as in a tomotherapy Hi-Art unit. In vivo measurements were performed on both a RANDO phantom and several head and neck cancer patients treated with tomotherapy and compared to TLD measurements and treatment plan doses to evaluate the performance of MOSFETs in a high gradient radiation field. The average calibration factor found was 0.345+/-2.5%cGy/mV for the high sensitivity MOSFETs tested and 0.901+/-2.4%cGy/mV for the standard sensitivity MOSFETs. MOSFET measured surface doses had an average agreement with ion chamber measurements of 1.55% for the high sensitivity MOSFET and 5.23% for the standard sensitivity MOSFET when averaged over all trials and field sizes tested. No significant dependence on field size was found for the standard sensitivity MOSFETs, however a maximum difference of 5.34% was found for the high sensitivity MOSFET calibration factors in the field sizes tested. Measurements made with MOSFETS on head and neck patients treated on a tomotherapy Hi-Art unit had an average agreement of (3.26+/-0.03)% with TLD measurements, however the average of the absolute difference between the MOSFET measurements and the treatment plan skin doses was (12.2+/-7.5)%. The MOSFET measured patient skin doses also had good reproducibility, with inter-fraction deviations ranging from 1.4% to 6.6%. Similar results were found from trials using a RANDO phantom. The MOSFETs performed well when used in the tomotherapy Hi-Art unit and did not increase the overall treatment set-up time when used for patient measurements. It was found that MOSFETs

  11. Tomotherapy for prostate adenocarcinoma: A report on acute toxicity

    International Nuclear Information System (INIS)

    Keiler, Louis; Dobbins, Donald; Kulasekere, Ravi; Einstein, Douglas

    2007-01-01

    Background and purpose: To analyze the impact of Tomotherapy (TOMO) intensity modulated radiotherapy (IMRT) on acute gastrointestinal (GI) and genitourinary (GU) toxicity in prostate cancer. Materials and methods: The records of 55 consecutively treated TOMO patients were reviewed. Additionally a well-matched group of 43 patients treated with LINAC-based step and shoot IMRT (LINAC) was identified. Acute toxicity was scored according to Radiation Therapy Oncology Group acute toxicity criterion. Results: The grade 2-3 acute GU toxicity rates for the TOMO vs. LINAC groups were 51% vs. 28% (p = 0.001). Acute grade 2 GI toxicity was 25% vs. 40% (p = 0.024), with no grade 3 GI toxicity in either group. In univariate analysis, androgen deprivation, prostate volume, pre-treatment urinary toxicity, and prostate dose homogeneity correlated with acute GI and GU toxicity. With multivariate analysis use of Tomotherapy, median bladder dose and bladder dose homogeneity remained significantly correlated with GU toxicity. Conclusions: Acute GI toxicity for prostate cancer is improved with Tomotherapy at a cost of increased acute GU toxicity possibly due to differences in bladder and prostate dose distribution

  12. Intensity-modulated radiotherapy for cancers in childhood

    International Nuclear Information System (INIS)

    Leseur, J.; Le Prise, E.; Leseur, J.; Carrie, C.; Beneyton, V.; Bernier, V.; Beneyton, V.; Mahee, M.A.; Supiot, S.

    2009-01-01

    Approximately 40-50% of children with cancer will be irradiated during their treatment. Intensity-modulated radiotherapy (I.M.R.T.) by linear accelerator or helical tomo-therapy improves dose distribution in target volumes and normal tissue sparing. This technology could be particularly useful for pediatric patients to achieve an optimal dose distribution in complex volumes close to critical structures. The use of I.M.R.T. can increase the volume of tissue receiving low-dose radiation, and consequently carcinogenicity in childhood population with a good overall survival and long period of life expectancy. This review will present the current and potential I.M.R.T. indications for cancers in childhood, and discuss the benefits and problems of this technology aiming to define recommendations in the use of I.M.R.T. and specific doses constraints in Pediatrics. (authors)

  13. 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.

  14. Accuracy of out-of-field dose calculation of tomotherapy and Cyberknife treatment planning systems. A dosimetric study

    International Nuclear Information System (INIS)

    Schneider, Uwe; Hirslanden Medical Center, Aarau; Haelg, Roger A.; Hartmann, Matthias; Mack, Andreas; Storelli, Fabrizio; Besserer, Juergen; Joosten, Andreas; Moeckli, Raphael

    2014-01-01

    Purpose: Late toxicities such as second cancer induction become more important as treatment outcome improves. Often the dose distribution calculated with a commercial treatment planning system (TPS) is used to estimate radiation carcinogenesis for the radiotherapy patient. However, for locations beyond the treatment field borders, the accuracy is not well known. The aim of this study was to perform detailed out-of-field-measurements for a typical radiotherapy treatment plan administered with a Cyberknife and a Tomotherapy machine and to compare the measurements to the predictions of the TPS. Materials and methods: Individually calibrated thermoluminescent dosimeters were used to measure absorbed dose in an anthropomorphic phantom at 184 locations. The measured dose distributions from 6 MV intensity-modulated treatment beams for CyberKnife and TomoTherapy machines were compared to the dose calculations from the TPS. Results: The TPS are underestimating the dose far away from the target volume. Quantitatively the Cyberknife underestimates the dose at 40 cm from the PTV border by a factor of 60, the Tomotherapy TPS by a factor of two. If a 50% dose uncertainty is accepted, the Cyberknife TPS can predict doses down to approximately 10 mGy/treatment Gy, the Tomotherapy-TPS down to 0.75 mGy/treatment Gy. The Cyberknife TPS can then be used up to 10 cm from the PTV border the Tomotherapy up to 35 cm. Conclusions: We determined that the Cyberknife and Tomotherapy TPS underestimate substantially the doses far away from the treated volume. It is recommended not to use out-of-field doses from the Cyberknife TPS for applications like modeling of second cancer induction. The Tomotherapy TPS can be used up to 35 cm from the PTV border (for a 390 cm 3 large PTV). (orig.)

  15. ARCHER{sub RT} – A GPU-based and photon-electron coupled Monte Carlo dose computing engine for radiation therapy: Software development and application to helical tomotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Su, Lin; Du, Xining; Liu, Tianyu; Ji, Wei; Xu, X. George, E-mail: xug2@rpi.edu [Nuclear Engineering Program, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Yang, Youming; Bednarz, Bryan [Medical Physics, University of Wisconsin, Madison, Wisconsin 53706 (United States); Sterpin, Edmond [Molecular Imaging, Radiotherapy and Oncology, Université catholique de Louvain, Brussels, Belgium 1348 (Belgium)

    2014-07-15

    specific architecture of GPU, modified Woodcock tracking algorithm performed inferior to the original one. ARCHER{sub RT} achieves a fast speed for PSF-based dose calculations. With a single M2090 card, the simulations cost about 60, 50, 80 s for three cases, respectively, with the 1% statistical error in the PTV. Using the latest K40 card, the simulations are 1.7–1.8 times faster. More impressively, six M2090 cards could finish the simulations in 8.9–13.4 s. For comparison, the same simulations on Intel E5-2620 (12 hyperthreading) cost about 500–800 s. Conclusions: ARCHER{sub RT} was developed successfully to perform fast and accurate MC dose calculation for radiotherapy using PSFs and patient CT phantoms.

  16. 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

  17. Evaluation of ovary dose for woman of childbearing age woman with breast cancer in tomotherapy

    International Nuclear Information System (INIS)

    Lee, Soo Hyeong; Park, Soo Yeon; Choi, Ji Min; Park, Ju Young; Kim, Jong Suk

    2014-01-01

    The aim of this study is to evaluate unwanted scattered dose to ovary by scattering and leakage generated from treatment fields of Tomotherapy for childbearing woman with breast cancer. The radiation treatments plans for left breast cancer were established using Tomotherapy planning system (Tomotherapy, Inc, USA). They were generated by using helical and direct Tomotherapy methods for comparison. The CT images for the planning were scanned with 2.5 mm slice thickness using anthropomorphic phantom (Alderson-Rando phantom, The Phantom Laboratory, USA). The measurement points for the ovary dose were determined at the points laterally 30 cm apart from mid-point of treatment field of the pelvis. The measurements were repeated five times and averaged using glass dosimeters (1.5 mm diameter and 12 mm of length) equipped with low-energy correction filter. The measures dose values were also converted to Organ Equivalent Dose (OED) by the linear exponential dose-response model. Scattered doses of ovary which were measured based on two methods of Tomo helical and Tomo direct showed average of 64.94±0.84 mGy and 37.64±1.20 mGy in left ovary part and average of 64.38±1.85 mGy and 32.96±1.11 mGy in right ovary part. This showed when executing Tomotherapy, measured scattered dose of Tomo Helical method which has relatively greater monitor units (MUs) and longer irradiation time are approximately 1.8 times higher than Tomo direct method. Scattered dose of left and right ovary of childbearing women is lower than ICRP recommended does which is not seriously worried level against the infertility and secondary cancer occurrence. However, as breast cancer occurrence ages become younger in the future and radiation therapy using high-precision image guidance equipment like Tomotherapy is developed, clinical follow-up studies about the ovary dose of childbearing women patients would be more required

  18. Evaluation of ovary dose for woman of childbearing age woman with breast cancer in tomotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Soo Hyeong; Park, Soo Yeon; Choi, Ji Min; Park, Ju Young; Kim, Jong Suk [Dept. of Radiation Oncology, Samsung Medical Center, Seoul (Korea, Republic of)

    2014-12-15

    The aim of this study is to evaluate unwanted scattered dose to ovary by scattering and leakage generated from treatment fields of Tomotherapy for childbearing woman with breast cancer. The radiation treatments plans for left breast cancer were established using Tomotherapy planning system (Tomotherapy, Inc, USA). They were generated by using helical and direct Tomotherapy methods for comparison. The CT images for the planning were scanned with 2.5 mm slice thickness using anthropomorphic phantom (Alderson-Rando phantom, The Phantom Laboratory, USA). The measurement points for the ovary dose were determined at the points laterally 30 cm apart from mid-point of treatment field of the pelvis. The measurements were repeated five times and averaged using glass dosimeters (1.5 mm diameter and 12 mm of length) equipped with low-energy correction filter. The measures dose values were also converted to Organ Equivalent Dose (OED) by the linear exponential dose-response model. Scattered doses of ovary which were measured based on two methods of Tomo helical and Tomo direct showed average of 64.94±0.84 mGy and 37.64±1.20 mGy in left ovary part and average of 64.38±1.85 mGy and 32.96±1.11 mGy in right ovary part. This showed when executing Tomotherapy, measured scattered dose of Tomo Helical method which has relatively greater monitor units (MUs) and longer irradiation time are approximately 1.8 times higher than Tomo direct method. Scattered dose of left and right ovary of childbearing women is lower than ICRP recommended does which is not seriously worried level against the infertility and secondary cancer occurrence. However, as breast cancer occurrence ages become younger in the future and radiation therapy using high-precision image guidance equipment like Tomotherapy is developed, clinical follow-up studies about the ovary dose of childbearing women patients would be more required.

  19. 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

  20. 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.

  1. Dosimetric evaluation of tomography and four-box field conformal radiotherapy in locally advanced rectal cancer

    International Nuclear Information System (INIS)

    Yu, Mina; Lee, Hyo Chun; Chung, Mi Joo; Kim, Sung Hwan; Lee, Jong Hoon; Jang, Hong Seok; Jeon, Dong Min; Cheon, Geum Seong

    2013-01-01

    To report the results of dosimetric comparison between intensity-modulated radiotherapy (IMRT) using Tomotherapy and four-box field conformal radiotherapy (CRT) for pelvic irradiation of locally advanced rectal cancer. Twelve patients with locally advanced rectal cancer who received a short course preoperative chemoradiotherapy (25 Gy in 5 fractions) on the pelvis using Tomotherapy, between July 2010 and December 2010, were selected. Using their simulation computed tomography scans, Tomotherapy and four-box field CRT plans with the same dose schedule were evaluated, and dosimetric parameters of the two plans were compared. For the comparison of target coverage, we analyzed the mean dose, Vn Gy, Dmin, Dmax, radical dose homogeneity index (rDHI), and radiation conformity index (RCI). For the comparison of organs at risk (OAR), we analyzed the mean dose. Tomotherapy showed a significantly higher mean target dose than four-box field CRT (p 0.001). But, V26.25 Gy and V27.5 Gywere not significantly different between the two modalities. Tomotherapy showed higher Dmax and lower Dmin. The Tomotherapy plan had a lower rDHI than four-box field CRT (p = 0.000). Tomotherapy showed better RCI than four-box field CRT (p = 0.007). For OAR, the mean irradiated dose was significantly lower in Tomotherapy than four-box field CRT. In locally advanced rectal cancer, Tomotherapy delivers a higher conformal radiation dose to the target and reduces the irradiated dose to OAR than four-box field CRT.

  2. Dosimetric evaluation of tomography and four-box field conformal radiotherapy in locally advanced rectal cancer

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Mina; Lee, Hyo Chun; Chung, Mi Joo; Kim, Sung Hwan; Lee, Jong Hoon [Dept. of Radiation Oncology, St. Vincent' s Hospital, The Catholic University of Korea College of Medicine, Suwon (Korea, Republic of); Jang, Hong Seok; Jeon, Dong Min; Cheon, Geum Seong [Dept. of Radiation Oncology, Seoul St. Mary' s Hospital, The Catholic University of Korea College of Medicine, Seoul (Korea, Republic of)

    2013-12-15

    To report the results of dosimetric comparison between intensity-modulated radiotherapy (IMRT) using Tomotherapy and four-box field conformal radiotherapy (CRT) for pelvic irradiation of locally advanced rectal cancer. Twelve patients with locally advanced rectal cancer who received a short course preoperative chemoradiotherapy (25 Gy in 5 fractions) on the pelvis using Tomotherapy, between July 2010 and December 2010, were selected. Using their simulation computed tomography scans, Tomotherapy and four-box field CRT plans with the same dose schedule were evaluated, and dosimetric parameters of the two plans were compared. For the comparison of target coverage, we analyzed the mean dose, Vn Gy, Dmin, Dmax, radical dose homogeneity index (rDHI), and radiation conformity index (RCI). For the comparison of organs at risk (OAR), we analyzed the mean dose. Tomotherapy showed a significantly higher mean target dose than four-box field CRT (p 0.001). But, V26.25 Gy and V27.5 Gywere not significantly different between the two modalities. Tomotherapy showed higher Dmax and lower Dmin. The Tomotherapy plan had a lower rDHI than four-box field CRT (p = 0.000). Tomotherapy showed better RCI than four-box field CRT (p = 0.007). For OAR, the mean irradiated dose was significantly lower in Tomotherapy than four-box field CRT. In locally advanced rectal cancer, Tomotherapy delivers a higher conformal radiation dose to the target and reduces the irradiated dose to OAR than four-box field CRT.

  3. Comparing the quality of passively-scattered proton and photon tomotherapy plans for brain and head and neck disease sites

    International Nuclear Information System (INIS)

    Kainz, Kristofer; Firat, Selim; Wilson, J Frank; Schultz, Christopher; Siker, Malika; Wang, Andrew; Olson, Dan; Allen Li, X

    2015-01-01

    We compare the quality of photon IMRT (helical tomotherapy) with classic proton plans for brain, head and neck tumors, in terms of target dose uniformity and conformity along with organ-at-risk (OAR) sparing. Plans were created for twelve target volumes among eight cases. All patients were originally planned and treated using helical tomotherapy. Proton plans were generated using a passively-scattered beam model with a maximum range of 32 g cm −2 (225 MeV), range modulation in 0.5 g cm −2 increments and range compensators with 4.8 mm milling tool diameters. All proton plans were limited to two to four beams. Plan quality was compared using uniformity index (UI), conformation number (CN) and a EUD-based plan quality index (fEUD). For 11 of the 12 targets, UI was improved for the proton plan; on average, UI was 1.05 for protons versus 1.08 for tomotherapy. For 7 of the 12 targets, the tomotherapy plan exhibited more favorable CN. For proximal OARs, the improved dose conformity to the target volume from tomotherapy led to a lower maximum dose. For distal OARs, the maximum dose was much lower for proton plans. For 6 of the 8 cases, near-total avoidance for distal OARs provided by protons leads to improved fEUD. However, if distal OARs are excluded in the fEUD calculation, the proton plans exhibit better fEUD in only 3 of the 8 cases. The distal OAR sparing and target dose uniformity are generally better with passive-scatter proton planning than with photon tomotherapy; proton therapy may be preferred if the clinician deems those attributes critical. However, tomotherapy may serve equally as well as protons for cases where superior target dose conformity from tomotherapy leads to plan quality nearly identical to or better than protons and for cases where distal OAR sparing is not concerning. (paper)

  4. 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

  5. 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)

  6. Evaluation of the room shielding thickness of Hi-Art tomotherapy system

    International Nuclear Information System (INIS)

    Liu Haikuan; Wu Jinhai; Gu Naigu; Gao Yiming; Wang Li; Huang Weiqin; Wang Fengxian

    2010-01-01

    In this paper, we calculate and evaluate the room shielding thickness of a Hi-Art tomotherapy system, which is a new type of radiotherapy facility. Due to the self-shielding of the accelerator,only scattered beam and beam leakage were considered in calculating the room shielding thickness. The radiation field of the tomotherapy system was used as the basic data to calculate the shielding thickness of every 15 degree solid angle. The maximum shielding thickness required of each shielding wall was at the position with the angle of 15 degree, and the calculated shielding thickness were 1023, 975, 917, 1460, 1147 and 1189 mm for the east wall,south wall,west wall, north wall, the roof and the floor,respectively. According to the calculation results, all shielding walls, ceiling and floor could meet the requirement of the radiation protection, but the north wall thickness of 1200 mm was a little thinner. (authors)

  7. Pelvic tomo-therapy among 70 to 90 year old patients: feasibility and tolerance; Tomotherapie pelvienne chez les sujets ages de 70 a 90 ans: faisabilite et tolerance

    Energy Technology Data Exchange (ETDEWEB)

    Bibault, J.E.; Nickers, P.; Castelain, B.; Lacornerie, T.; Reynaert, N.; Lartigau, E. [Centre Oscar-Lambret, 59 - Lille (France)

    2010-10-15

    As population is getting older (the number of people older than 70 years will double by 2030), it is important to assess the feasibility and tolerance of new irradiation techniques, notably the intensity-modulated radiotherapy, for elderly people, particularly in the case of pelvic tumours. Based on a sample of 18 patients, the authors notice that tomo-therapy reduces the digestive and urinary toxicity, and thus could be used for the treatment of aged patients, even 80 to 90 year old patients in good general status. However, these results need to be confirmed by a study on a larger scale. Short communication

  8. Design and implementation of a ''cheese'' phantom-based Tomotherapy TLD dose intercomparison

    Energy Technology Data Exchange (ETDEWEB)

    Schiefer, Hans; Buchauer, Konrad; Heinze, Simon [Medical Physics Group, Department of Radiation Oncology, St. Gallen (Switzerland); Henke, Guido; Plasswilm, Ludwig [Department of Radiation Oncology, St. Gallen (Switzerland)

    2015-11-15

    The unique beam-delivery technique of Tomotherapy machines (Accuray Inc., Sunnyvale, Calif.) necessitates tailored quality assurance. This requirement also applies to external dose intercomparisons. Therefore, the aim of the 2014 SSRMP (Swiss Society of Radiobiology and Medical Physics) dosimetry intercomparison was to compare two set-ups with different phantoms. A small cylindrical Perspex phantom, which is similar to the IROC phantom (Imaging and Radiation Oncology Core, Houston, Tex.), and the ''cheese'' phantom, which is provided by the Tomotherapy manufacturer to all institutions, were used. The standard calibration plans for the TomoHelical and TomoDirect irradiation techniques were applied. These plans are routinely used for dose output calibration in Tomotherapy institutions. We tested 20 Tomotherapy machines in Germany and Switzerland. The ratio of the measured (D{sub m}) to the calculated (D{sub c}) dose was assessed for both phantoms and irradiation techniques. The D{sub m}/D{sub c} distributions were determined to compare the suitability of the measurement set-ups investigated. The standard deviations of the TLD-measured (thermoluminescent dosimetry) D{sub m}/D{sub c} ratios for the ''cheese'' phantom were 1.9 % for the TomoHelical (19 measurements) and 1.2 % (11 measurements) for the TomoDirect irradiation techniques. The corresponding ratios for the Perspex phantom were 2.8 % (18 measurements) and 1.8 % (11 measurements). Compared with the Perspex phantom-based set-up, the ''cheese'' phantom-based set-up without individual planning was demonstrated to be more suitable for Tomotherapy dose checks. Future SSRMP dosimetry intercomparisons for Tomotherapy machines will therefore be based on the ''cheese'' phantom set-up. (orig.) [German] Die einzigartige Bestrahlungstechnik mit Tomotherapie-Bestrahlungsgeraeten (Accuray Inc., Sunnyvale, CA, USA) erfordert spezifische

  9. The dosimetric control in radiotherapy

    International Nuclear Information System (INIS)

    Veres, A.

    2009-01-01

    The author first presents the thermoluminescent dosimetry method developed by the Equal-Estro Laboratory to control radiotherapy systems, according to which dosimeters are mailed by the radiotherapy centres to the laboratory, and then analyzed with respect to the level of dose bias. In a second part, he discusses the different techniques used for the dosimetric control of new radiotherapy methods (intensity-modulated radiation therapy, tomo-therapy) for which film dosimetry is applied. He also evokes the development of new phantoms and the development of a method for the dosimetric control of proton beams

  10. Setup Variations in Radiotherapy of Esophageal Cancer: Evaluation by Daily Megavoltage Computed Tomographic Localization

    International Nuclear Information System (INIS)

    Chen, Y.-J.; Han Chunhui; Liu An; Schultheiss, Timothy E.; Kernstine, Kemp H.; Shibata, Stephen; Vora, Nayana L.; Pezner, Richard D.; Wong, Jeffrey Y.C.

    2007-01-01

    Purpose: To use pretreatment megavoltage computed tomography (MVCT) scans to evaluate setup variations in anterior-posterior (AP), lateral, and superior-inferior (SI) directions and rotational variations, including pitch, roll, and yaw, for esophageal cancer patients treated with helical tomotherapy. Methods and Materials: Ten patients with locally advanced esophageal cancer treated by combined chemoradiation using helical tomotherapy were selected. After patients were positioned using their skin tattoos/marks, MVCT scans were performed before every treatment and automatically registered to planning kilovoltage CT scans according to bony landmarks. Image registration data were used to adjust patient setups before treatment. A total of 250 MVCT scans were analyzed. Correlations between setup variations and body habitus, including height, weight, relative weight change, body surface area, and patient age, were evaluated. Results: The standard deviations for systematic setup corrections in AP, lateral, and SI directions and pitch, roll, and yaw rotations were 1.5, 3.7, and 4.8 mm and 0.5 deg., 1.2 deg., and 0.8 deg., respectively. The appropriate averages of random setup variations in AP, lateral, and SI directions and pitch, roll, and yaw rotations were 2.9, 5.2, and 4.4 mm, and 1.0 deg., 1.2 deg., and 1.1 deg., respectively. Setup variations were stable throughout the entire course of radiotherapy in all three translational and three rotational displacements, with little change in magnitude. No significant correlations were found between setup variations and body habitus variables. Conclusions: Daily MVCT scans before each treatment can effectively detect setup errors and thereby reduce planning target volume (PTV) margins. This will reduce radiation dose to critical organs and may translate into lower treatment-related toxicities

  11. Preliminary Retrospective Analysis of Daily Tomotherapy Output Constancy Checks Using Statistical Process Control.

    Science.gov (United States)

    Mezzenga, Emilio; D'Errico, Vincenzo; Sarnelli, Anna; Strigari, Lidia; Menghi, Enrico; Marcocci, Francesco; Bianchini, David; Benassi, Marcello

    2016-01-01

    The purpose of this study was to retrospectively evaluate the results from a Helical TomoTherapy Hi-Art treatment system relating to quality controls based on daily static and dynamic output checks using statistical process control methods. Individual value X-charts, exponentially weighted moving average charts, and process capability and acceptability indices were used to monitor the treatment system performance. Daily output values measured from January 2014 to January 2015 were considered. The results obtained showed that, although the process was in control, there was an out-of-control situation in the principal maintenance intervention for the treatment system. In particular, process capability indices showed a decreasing percentage of points in control which was, however, acceptable according to AAPM TG148 guidelines. Our findings underline the importance of restricting the acceptable range of daily output checks and suggest a future line of investigation for a detailed process control of daily output checks for the Helical TomoTherapy Hi-Art treatment system.

  12. Pelvic tomo-therapy among 70 to 90 year old patients: feasibility and tolerance

    International Nuclear Information System (INIS)

    Bibault, J.E.; Nickers, P.; Castelain, B.; Lacornerie, T.; Reynaert, N.; Lartigau, E.

    2010-01-01

    As population is getting older (the number of people older than 70 years will double by 2030), it is important to assess the feasibility and tolerance of new irradiation techniques, notably the intensity-modulated radiotherapy, for elderly people, particularly in the case of pelvic tumours. Based on a sample of 18 patients, the authors notice that tomo-therapy reduces the digestive and urinary toxicity, and thus could be used for the treatment of aged patients, even 80 to 90 year old patients in good general status. However, these results need to be confirmed by a study on a larger scale. Short communication

  13. Retrospective feasibility study of simultaneous integrated boost in cervical cancer using Tomotherapy: the impact of organ motion and tumor regression.

    Science.gov (United States)

    Herrera, Fernanda G; Callaway, Sharon; Delikgoz-Soykut, Ela; Coskun, Mehtap; Porta, Laetitia; Meuwly, Jean-Yves; Soares-Rodrigues, Joao; Heym, Leonie; Moeckli, Raphael; Ozsahin, Mahmut

    2013-01-03

    Whole pelvis intensity modulated radiotherapy (IMRT) is increasingly being used to treat cervical cancer aiming to reduce side effects. Encouraged by this, some groups have proposed the use of simultaneous integrated boost (SIB) to target the tumor, either to get a higher tumoricidal effect or to replace brachytherapy. Nevertheless, physiological organ movement and rapid tumor regression throughout treatment might substantially reduce any benefit of this approach. To evaluate the clinical target volume - simultaneous integrated boost (CTV-SIB) regression and motion during chemo-radiotherapy (CRT) for cervical cancer, and to monitor treatment progress dosimetrically and volumetrically to ensure treatment goals are met. Ten patients treated with standard doses of CRT and brachytherapy were retrospectively re-planned using a helical Tomotherapy - SIB technique for the hypothetical scenario of this feasibility study. Target and organs at risk (OAR) were contoured on deformable fused planning-computed tomography and megavoltage computed tomography images. The CTV-SIB volume regression was determined. The center of mass (CM) was used to evaluate the degree of motion. The Dice's similarity coefficient (DSC) was used to assess the spatial overlap of CTV-SIBs between scans. A cumulative dose-volume histogram modeled estimated delivered doses. The CTV-SIB relative reduction was between 31 and 70%. The mean maximum CM change was 12.5, 9, and 3 mm in the superior-inferior, antero-posterior, and right-left dimensions, respectively. The CTV-SIB-DSC approached 1 in the first week of treatment, indicating almost perfect overlap. CTV-SIB-DSC regressed linearly during therapy, and by the end of treatment was 0.5, indicating 50% discordance. Two patients received less than 95% of the prescribed dose. Much higher doses to the OAR were observed. A multiple regression analysis showed a significant interaction between CTV-SIB reduction and OAR dose increase. The CTV-SIB had important

  14. Retrospective feasibility study of simultaneous integrated boost in cervical cancer using tomotherapy: the impact of organ motion and tumor regression

    International Nuclear Information System (INIS)

    Herrera, Fernanda G; Ozsahin, Mahmut; Callaway, Sharon; Delikgoz-Soykut, Ela; Coskun, Mehtap; Porta, Laetitia; Meuwly, Jean-Yves; Soares-Rodrigues, Joao; Heym, Leonie; Moeckli, Raphael

    2013-01-01

    Whole pelvis intensity modulated radiotherapy (IMRT) is increasingly being used to treat cervical cancer aiming to reduce side effects. Encouraged by this, some groups have proposed the use of simultaneous integrated boost (SIB) to target the tumor, either to get a higher tumoricidal effect or to replace brachytherapy. Nevertheless, physiological organ movement and rapid tumor regression throughout treatment might substantially reduce any benefit of this approach. To evaluate the clinical target volume - simultaneous integrated boost (CTV-SIB) regression and motion during chemo-radiotherapy (CRT) for cervical cancer, and to monitor treatment progress dosimetrically and volumetrically to ensure treatment goals are met. Ten patients treated with standard doses of CRT and brachytherapy were retrospectively re-planned using a helical Tomotherapy - SIB technique for the hypothetical scenario of this feasibility study. Target and organs at risk (OAR) were contoured on deformable fused planning-computed tomography and megavoltage computed tomography images. The CTV-SIB volume regression was determined. The center of mass (CM) was used to evaluate the degree of motion. The Dice’s similarity coefficient (DSC) was used to assess the spatial overlap of CTV-SIBs between scans. A cumulative dose-volume histogram modeled estimated delivered doses. The CTV-SIB relative reduction was between 31 and 70%. The mean maximum CM change was 12.5, 9, and 3 mm in the superior-inferior, antero-posterior, and right-left dimensions, respectively. The CTV-SIB-DSC approached 1 in the first week of treatment, indicating almost perfect overlap. CTV-SIB-DSC regressed linearly during therapy, and by the end of treatment was 0.5, indicating 50% discordance. Two patients received less than 95% of the prescribed dose. Much higher doses to the OAR were observed. A multiple regression analysis showed a significant interaction between CTV-SIB reduction and OAR dose increase. The CTV-SIB had important

  15. Retrospective feasibility study of simultaneous integrated boost in cervical cancer using tomotherapy: the impact of organ motion and tumor regression

    Directory of Open Access Journals (Sweden)

    Herrera Fernanda G

    2013-01-01

    Full Text Available Abstract Background Whole pelvis intensity modulated radiotherapy (IMRT is increasingly being used to treat cervical cancer aiming to reduce side effects. Encouraged by this, some groups have proposed the use of simultaneous integrated boost (SIB to target the tumor, either to get a higher tumoricidal effect or to replace brachytherapy. Nevertheless, physiological organ movement and rapid tumor regression throughout treatment might substantially reduce any benefit of this approach. Purpose To evaluate the clinical target volume - simultaneous integrated boost (CTV-SIB regression and motion during chemo-radiotherapy (CRT for cervical cancer, and to monitor treatment progress dosimetrically and volumetrically to ensure treatment goals are met. Methods and materials Ten patients treated with standard doses of CRT and brachytherapy were retrospectively re-planned using a helical Tomotherapy - SIB technique for the hypothetical scenario of this feasibility study. Target and organs at risk (OAR were contoured on deformable fused planning-computed tomography and megavoltage computed tomography images. The CTV-SIB volume regression was determined. The center of mass (CM was used to evaluate the degree of motion. The Dice’s similarity coefficient (DSC was used to assess the spatial overlap of CTV-SIBs between scans. A cumulative dose-volume histogram modeled estimated delivered doses. Results The CTV-SIB relative reduction was between 31 and 70%. The mean maximum CM change was 12.5, 9, and 3 mm in the superior-inferior, antero-posterior, and right-left dimensions, respectively. The CTV-SIB-DSC approached 1 in the first week of treatment, indicating almost perfect overlap. CTV-SIB-DSC regressed linearly during therapy, and by the end of treatment was 0.5, indicating 50% discordance. Two patients received less than 95% of the prescribed dose. Much higher doses to the OAR were observed. A multiple regression analysis showed a significant interaction

  16. Xerostomia after radiotherapy. What matters - mean total dose or dose to each parotid gland?

    International Nuclear Information System (INIS)

    Tribius, S.; Sommer, J.; Prosch, C.; Bajrovic, A.; Kruell, A.; Petersen, C.; Muenscher, A.; Blessmann, M.; Todorovic, M.; Tennstedt, P.

    2013-01-01

    Purpose: Xerostomia is a debilitating side effect of radiotherapy in patients with head and neck cancer. We undertook a prospective study of the effect on xerostomia and outcomes of sparing one or both parotid glands during radiotherapy for patients with squamous cell carcinoma of the head and neck. Methods and materials: Patients with locally advanced squamous cell carcinoma of the head and neck received definitive (70 Gy in 2 Gy fractions) or adjuvant (60-66 Gy in 2 Gy fractions) curative-intent radiotherapy using helical tomotherapy with concurrent chemotherapy if appropriate. Group A received < 26 Gy to the left and right parotids and group B received < 26 Gy to either parotid. Results: The study included 126 patients; 114 (55 in group A and 59 in group B) had follow-up data. There were no statistically significant differences between groups in disease stage. Xerostomia was significantly reduced in group A vs. group B (p = 0.0381). Patients in group A also had significantly less dysphagia. Relapse-free and overall survival were not compromised in group A: 2-year relapse-free survival was 86% vs. 72% in group B (p = 0.361); 2-year overall survival was 88% and 76%, respectively (p = 0.251). Conclusion: This analysis suggests that reducing radiotherapy doses to both parotid glands to < 26 Gy can reduce xerostomia and dysphagia significantly without compromising survival. Sparing both parotids while maintaining target volume coverage and clinical outcome should be the treatment goal and reporting radiotherapy doses delivered to the individual parotids should be standard practice. (orig.)

  17. Xerostomia after radiotherapy. What matters - mean total dose or dose to each parotid gland?

    Energy Technology Data Exchange (ETDEWEB)

    Tribius, S.; Sommer, J.; Prosch, C.; Bajrovic, A.; Kruell, A.; Petersen, C. [University Medical Center Hamburg-Eppendorf, Hamburg (Germany). Dept. of Radiation Oncology; Muenscher, A. [University Medical Center Hamburg-Eppendorf, Hamburg (Germany). Dept. of Otorhinolaryngology and Head and Neck Surgery; Blessmann, M. [University Medical Center Hamburg-Eppendorf, Hamburg (Germany). Dept. of Oral and Maxillofacial Surgery; Todorovic, M. [University Medical Center Hamburg-Eppendorf, Hamburg (Germany). Dept. of Medical Physics; Tennstedt, P. [University Medical Center Hamburg-Eppendorf, Hamburg (Germany). Martini-Clinic, Prostate Cancer Center

    2013-03-15

    Purpose: Xerostomia is a debilitating side effect of radiotherapy in patients with head and neck cancer. We undertook a prospective study of the effect on xerostomia and outcomes of sparing one or both parotid glands during radiotherapy for patients with squamous cell carcinoma of the head and neck. Methods and materials: Patients with locally advanced squamous cell carcinoma of the head and neck received definitive (70 Gy in 2 Gy fractions) or adjuvant (60-66 Gy in 2 Gy fractions) curative-intent radiotherapy using helical tomotherapy with concurrent chemotherapy if appropriate. Group A received < 26 Gy to the left and right parotids and group B received < 26 Gy to either parotid. Results: The study included 126 patients; 114 (55 in group A and 59 in group B) had follow-up data. There were no statistically significant differences between groups in disease stage. Xerostomia was significantly reduced in group A vs. group B (p = 0.0381). Patients in group A also had significantly less dysphagia. Relapse-free and overall survival were not compromised in group A: 2-year relapse-free survival was 86% vs. 72% in group B (p = 0.361); 2-year overall survival was 88% and 76%, respectively (p = 0.251). Conclusion: This analysis suggests that reducing radiotherapy doses to both parotid glands to < 26 Gy can reduce xerostomia and dysphagia significantly without compromising survival. Sparing both parotids while maintaining target volume coverage and clinical outcome should be the treatment goal and reporting radiotherapy doses delivered to the individual parotids should be standard practice. (orig.)

  18. SU-E-T-197: Helical Cranial-Spinal Treatments with a Linear Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, J; Bernard, D; Liao, Y; Templeton, A; Turian, J; Chu, J [Rush University Medical Center, Chicago, IL (United States)

    2014-06-01

    Purpose: Craniospinal irradiation (CSI) of systemic disease requires a high level of beam intensity modulation to reduce dose to bone marrow and other critical structures. Current helical delivery machines can take 30 minutes or more of beam-on time to complete these treatments. This pilot study aims to test the feasibility of performing helical treatments with a conventional linear accelerator using longitudinal couch travel during multiple gantry revolutions. Methods: The VMAT optimization package of the Eclipse 10.0 treatment planning system was used to optimize pseudo-helical CSI plans of 5 clinical patient scans. Each gantry revolution was divided into three 120° arcs with each isocenter shifted longitudinally. Treatments requiring more than the maximum 10 arcs used multiple plans with each plan after the first being optimized including the dose of the others (Figure 1). The beam pitch was varied between 0.2 and 0.9 (couch speed 5- 20cm/revolution and field width of 22cm) and dose-volume histograms of critical organs were compared to tomotherapy plans. Results: Viable pseudo-helical plans were achieved using Eclipse. Decreasing the pitch from 0.9 to 0.2 lowered the maximum lens dose by 40%, the mean bone marrow dose by 2.1% and the maximum esophagus dose by 17.5%. (Figure 2). Linac-based helical plans showed dose results comparable to tomotherapy delivery for both target coverage and critical organ sparing, with the D50 of bone marrow and esophagus respectively 12% and 31% lower in the helical linear accelerator plan (Figure 3). Total mean beam-on time for the linear accelerator plan was 8.3 minutes, 54% faster than the tomotherapy average for the same plans. Conclusions: This pilot study has demonstrated the feasibility of planning pseudo-helical treatments for CSI targets using a conventional linac and dynamic couch movement, and supports the ongoing development of true helical optimization and delivery.

  19. Adjuvant radiotherapy after extrapleural pneumonectomy for mesothelioma. Prospective analysis of a multi-institutional series

    International Nuclear Information System (INIS)

    Tonoli, Sandro; Vitali, Paola; Scotti, Vieri; Bertoni, Filippo; Spiazzi, Luigi; Ghedi, Barbara; Buonamici, Fabrizio Banci; Marrazzo, Livia; Guidi, Gabriele; Meattini, Icro; Bastiani, Paolo; Amichetti, Maurizio; Schwarz, Marco; Magrini, Stefano Maria

    2011-01-01

    Background and purpose: To evaluate survival, locoregional control and toxicity in a series of 56 mesothelioma patients treated from May 2005 to May 2010 with post-operative radiotherapy after extrapleural pneumonectomy (EPP) in three Italian Institutions (Brescia, Florence, and Modena). Material and methods: Fifty-six patients treated with adjuvant radiotherapy (RT) after EPP were analyzed. Four patients were treated with 3DCRT, 50 with IMRT and two with helical tomotherapy. Forty-five to 50 Gy in 25 fractions were given to the affected hemithorax and to ipsilateral mediastinum, with a simultaneous integrated boost to the sites of microscopically involved margins up to 60 Gy in 20/56 cases. Results: Three year locoregional control (LRC), distant metastasis free (DMF), disease free (DF), disease specific (DSS) and overall survival (OS) rates are 90%, 66%, 57%, 62%, and 60%, respectively. Conclusion: Postoperative RT with modern techniques is an effective method to obtain excellent local control and cure rates in mesothelioma patients submitted to EPP.

  20. Helical filaments

    Energy Technology Data Exchange (ETDEWEB)

    Barbieri, Nicholas; Lim, Khan; Durand, Magali; Baudelet, Matthieu; Richardson, Martin [Townes Laser Institute, CREOL—The College of Optics and Photonics, University of Central Florida, Orlando, Florida 32816 (United States); Hosseinimakarem, Zahra; Johnson, Eric [Micro-Photonics Laboratory – Center for Optical Material Science, Clemson, Anderson, South Carolina 29634 (United States)

    2014-06-30

    The shaping of laser-induced filamenting plasma channels into helical structures by guiding the process with a non-diffracting beam is demonstrated. This was achieved using a Bessel beam superposition to control the phase of an ultrafast laser beam possessing intensities sufficient to induce Kerr effect driven non-linear self-focusing. Several experimental methods were used to characterize the resulting beams and confirm the observed structures are laser air filaments.

  1. SU-E-T-370: Evaluating Plan Quality and Dose Delivery Accuracy of Tomotherapy SBRT Treatments for Lung Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Blake, S; Thwaites, D [University of Sydney, Sydney, NSW (Australia); Hansen, C [Odense University Hospital, Odense C (Denmark); Deshpande, S; Phan, P; Franji, I [Liverpool & Macarthur Cancer Therapy Centres, Liverpool, NSW (United Kingdom); Holloway, L [Ingham Institute, Sydney, NSW (Australia)

    2015-06-15

    Purpose: This study evaluated the plan quality and dose delivery accuracy of stereotactic body radiotherapy (SBRT) helical Tomotherapy (HT) treatments for lung cancer. Results were compared with those previously reported by our group for flattening filter (FF) and flattening filter free (FFF) VMAT treatments. This work forms part of an ongoing multicentre and multisystem planning and dosimetry audit on FFF beams for lung SBRT. Methods: CT datasets and DICOM RT structures delineating the target volume and organs at risk for 6 lung cancer patients were selected. Treatment plans were generated using the HT treatment planning system. Tumour locations were classified as near rib, near bronchial tree or in free lung with prescribed doses of 48Gy/4fr, 50Gy/5fr and 54Gy/3fr respectively. Dose constraints were specified by a modified RTOG0915 protocol used for an Australian SBRT phase II trial. Plan quality was evaluated using mean PTV dose, PTV volume receiving 100% of the prescribed dose (V100%), target conformity (CI=VD100%/VPTV) and low dose spillage (LDS=VD50%/VPTV). Planned dose distributions were compared to those measured using an ArcCheck phantom. Delivery accuracy was evaluated using a gamma-index pass rate of 95% with 3% (of max dose) and 3mm criteria. Results: Treatment plans for all patients were clinically acceptable in terms of quality and accuracy of dose delivery. The following DVH metrics are reported as averages (SD) of all plans investigated: mean PTV dose was 115.3(2.4)% of prescription, V100% was 98.8(0.9)%, CI was 1.14(0.03) and LDS was 5.02(0.37). The plans had an average gamma-index passing rate of 99.3(1.3)%. Conclusion: The results reported in this study for HT agree within 1 SD to those previously published by our group for VMAT FF and FFF lung SBRT treatments. This suggests that HT delivers lung SBRT treatments of comparable quality and delivery accuracy as VMAT using both FF and FFF beams.

  2. Acute Toxicity in Definitive Versus Postprostatectomy Image-Guided Radiotherapy for Prostate Cancer

    International Nuclear Information System (INIS)

    Cheng, Jonathan C.; Schultheiss, Timothy E.; Nguyen, Khanh H.; Wong, Jeffrey Y.C.

    2008-01-01

    Purpose: To assess the incidence of acute gastrointestinal (GI) and genitourinary (GU) injury and the dose-volume response in patients with clinically localized prostate cancer treated with image-guided radiotherapy using helical tomotherapy. Methods and Materials: Between November 2004 and March 2007, 146 consecutive patients with localized prostate cancer were treated with helical tomotherapy at the City of Hope Medical Center. Of the 146 patients, 70 had undergone prostatectomy. Acute GI and GU toxicities were evaluated using the Radiation Therapy Oncology Group/European Organization for Research and Cancer of Medical scoring system. Events were scored for patients developing Grade 2 or greater morbidity within 90 days after the end of radiotherapy (RT). The dosimetric parameters included the minimal dose received by the highest 10%, 20%, 50%, 80%, and 90% of the target volume, the mean rectal dose, minimal rectal dose, maximal rectal dose, and the volume receiving ≥45, ≥65, and ≥70 Gy. These variables, plus the status of radical prostatectomy, hormonal therapy, RT techniques, and medical conditions, were included in a multivariate logistic regression analysis. A goodness-of-fit evaluation was done using the Hosmer-Lemeshow statistic. Results: A dose-response function for acute GI toxicity was elicited. The acute GI Grade 2 or greater toxicity was lower in the definitive RT group than in the postoperative RT group (25% vs. 41%, p <0.05). Acute GU Grade 2 or greater toxicity was comparable between the two groups. No grade 3 or greater complications were observed. No dosimetric variable was significant for GU toxicity. For acute GI toxicity, the significant dosimetric parameters were the minimal dose received by 10%, 20%, and 50% of the target volume and the mean rectal dose; the most predictive parameter was the minimal dose received by 10% of the target volume. The dose-modifying factor was 1.2 for radical prostatectomy. Conclusion: The results of our

  3. Complete response in a patient with gynecological hidradenocarcinoma treated with exclusive external beam radiotherapy and brachytherapy: a case report.

    Science.gov (United States)

    Giannelli, Flavio; Chiola, Ilaria; Belgioia, Liliana; Garelli, Stefania; Pastorino, Alice; Marcenaro, Michela; Mammoliti, Serafina; Costantini, Sergio; Bizzarri, Nicolò; Vellone, Valerio; Barra, Salvina; Corvò, Renzo

    2017-12-01

    Hidradenocarcinoma (HC) is a very rare disease. This case report illustrates a successful treatment of a 60-year-old woman with vulvo-vaginal localization of hidradenocarcinoma treated with external beam radiotherapy delivered by helical tomotherapy with a simultaneous integrated boost (SIB), followed by brachytherapy. External beam radiotherapy dose prescription was 50.4 Gy in 28 fractions, five fractions per week to whole pelvis (planning target volume 1 - PTV1), 60.2 Gy in 28 fractions to SIB1 (fundus of uterus and right inguinal node), and 58.8 Gy in 28 fractions to SIB2 (lower/middle third of vagina, paraurethral region and right inguinal lymph nodes). Brachytherapy dose prescription was 28 Gy in 4 fractions for cervix, fundus of uterus and upper third of vagina (HR-CTV1), and 22 Gy in 4 fractions to middle third of vagina and paraurethral region (HR-CTV2). D 90 for whole treatment was 91.9 Gy and 86.0 Gy for HR-CTV1 and HR-CTV2, respectively. Patient remained 12-months disease-free without treatment related side effects.

  4. Complete response in a patient with gynecological hidradenocarcinoma treated with exclusive external beam radiotherapy and brachytherapy: a case report

    Directory of Open Access Journals (Sweden)

    Flavio Giannelli

    2017-12-01

    Full Text Available Hidradenocarcinoma (HC is a very rare disease. This case report illustrates a successful treatment of a 60-year-old woman with vulvo-vaginal localization of hidradenocarcinoma treated with external beam radiotherapy delivered by helical tomotherapy with a simultaneous integrated boost (SIB, followed by brachytherapy. External beam radiotherapy dose prescription was 50.4 Gy in 28 fractions, five fractions per week to whole pelvis (planning target volume 1 – PTV1, 60.2 Gy in 28 fractions to SIB1 (fundus of uterus and right inguinal node, and 58.8 Gy in 28 fractions to SIB2 (lower/middle third of vagina, paraurethral region and right inguinal lymph nodes. Brachytherapy dose prescription was 28 Gy in 4 fractions for cervix, fundus of uterus and upper third of vagina (HR-CTV1, and 22 Gy in 4 fractions to middle third of vagina and paraurethral region (HR-CTV2. D90 for whole treatment was 91.9 Gy and 86.0 Gy for HR-CTV1 and HR-CTV2, respectively. Patient remained 12-months disease-free without treatment related side effects.

  5. Serial megavoltage CT imaging during external beam radiotherapy for non-small-cell lung cancer: Observations on tumor regression during treatment

    International Nuclear Information System (INIS)

    Kupelian, Patrick A.; Ramsey, Chester; Meeks, Sanford L.; Willoughby, Twyla R.; Forbes, Alan; Wagner, Thomas H.; Langen, Katja M.

    2005-01-01

    Purpose: The ability to obtain soft-tissue imaging in the treatment room, such as with megavoltage CT imaging, enables the observation of tumor regression during a course of external beam radiation therapy. In this current study, we report on the most extensive study looking at the rate of regression of non-small-cell lung cancers during a course of external beam radiotherapy by analyzing serial megavoltage CT images obtained on 10 patients. Methods and Materials: The analysis is performed on 10 patients treated with the Helical Tomotherapy Hi*Art device. All 10 patients had non-small-cell lung cancer. A total of 274 megavoltage CT sets were obtained on the 10 patients (average, 27 scans per patient; range, 9-35). All patients had at least a scan at beginning and at the end of treatment. The frequency of scanning was determined by the treating physician. The treatment was subsequently delivered with the Tomotherapy Hi*Art system. The gross tumor volumes (GTVs) were later contoured on each megavoltage CT scan, and tumor volumes were calculated. Although some patients were treated to draining nodal areas in addition to the primary tumor, only the primary GTVs were tracked. Response to treatment was quantified by the relative decrease in tumor volume over time, i.e., elapsed days from the first day of therapy. The individual GTVs ranged from 5.9 to 737.2 cc in volume at the start of treatment. In 6 of the 10 patients, dose recalculations were also performed to document potential variations in delivered doses within the tumors. The megavoltage CT scans were used, and the planned treatment was recalculated on the daily images. The hypothesis was that dose deposited in the target would increase throughout the course of radiotherapy because of tumor shrinkage and subsequent decreasing attenuation. Specifically, the dose received by 95% of the GTV (D 95 ) was monitored over time for each of the 6 patients treated at M.D. Anderson Cancer Center Orlando. Results: Regression

  6. Validation of GPU based TomoTherapy dose calculation engine.

    Science.gov (United States)

    Chen, Quan; Lu, Weiguo; Chen, Yu; Chen, Mingli; Henderson, Douglas; Sterpin, Edmond

    2012-04-01

    The graphic processing unit (GPU) based TomoTherapy convolution/superposition(C/S) dose engine (GPU dose engine) achieves a dramatic performance improvement over the traditional CPU-cluster based TomoTherapy dose engine (CPU dose engine). Besides the architecture difference between the GPU and CPU, there are several algorithm changes from the CPU dose engine to the GPU dose engine. These changes made the GPU dose slightly different from the CPU-cluster dose. In order for the commercial release of the GPU dose engine, its accuracy has to be validated. Thirty eight TomoTherapy phantom plans and 19 patient plans were calculated with both dose engines to evaluate the equivalency between the two dose engines. Gamma indices (Γ) were used for the equivalency evaluation. The GPU dose was further verified with the absolute point dose measurement with ion chamber and film measurements for phantom plans. Monte Carlo calculation was used as a reference for both dose engines in the accuracy evaluation in heterogeneous phantom and actual patients. The GPU dose engine showed excellent agreement with the current CPU dose engine. The majority of cases had over 99.99% of voxels with Γ(1%, 1 mm) engine also showed similar degree of accuracy in heterogeneous media as the current TomoTherapy dose engine. It is verified and validated that the ultrafast TomoTherapy GPU dose engine can safely replace the existing TomoTherapy cluster based dose engine without degradation in dose accuracy.

  7. Variation in radiotherapy target volume definition, dose to organs at risk and clinical target volumes using anatomic (computed tomography) versus combined anatomic and molecular imaging (positron emission tomography/computed tomography): intensity-modulated radiotherapy delivered using a tomotherapy Hi Art machine: final results of the VortigERN study.

    Science.gov (United States)

    Chatterjee, S; Frew, J; Mott, J; McCallum, H; Stevenson, P; Maxwell, R; Wilsdon, J; Kelly, C G

    2012-12-01

    Contrast-enhanced computed tomography (CECT) is the current standard for delineating tumours of the head and neck for radiotherapy. Although metabolic imaging with positron emission tomography (PET) has been used in recent years, the studies were non-confirmatory in establishing its routine role in radiotherapy planning in the modern era. This study explored the difference in gross tumour volume and clinical target volume definitions for the primary and nodal volumes when FDG PET/CT was used as compared with CECT in oropharyngeal cancer cases. Twenty patients with oropharyngeal cancers had a PET/CT scan in the treatment position after consent. Target volumes were defined on CECT scans by a consultant clinical oncologist who was blind to the PET scans. After obtaining inputs from a radiologist, another set of target volumes were outlined on the PET/CT data set. The gross and clinical target volumes as defined on the two data sets were then analysed. The hypothesis of more accurate target delineation, preventing geographical miss and comparative overlap volumes between CECT and PET/CT, was explored. The study also analysed the volumes of intersection and analysed whether there was any TNM stage migration when PET/CT was used as compared with CECT for planning. In 17 of 20 patients, the TNM stage was not altered when adding FDG PET information to CT. PET information prevented geographical miss in two patients and identified distant metastases in one case. PET/CT gross tumour volumes were smaller than CECT volumes (mean ± standard deviation: 25.16 cm(3) ± 35.8 versus 36.56 cm(3) ± 44.14; P standard deviation: CECT versus PET/CT 32.48 cm(3) ± 36.63 versus 32.21 cm(3) ± 37.09; P > 0.86) were not statistically different. Similarity and discordance coefficients were calculated and are reported. PET/CT as compared with CECT could provide more clinically relevant information and prevent geographical miss when used for radiotherapy planning for advanced oropharyngeal

  8. Intensity-Modulated Whole Abdominal Radiotherapy After Surgery and Carboplatin/Taxane Chemotherapy for Advanced Ovarian Cancer: Phase I Study

    International Nuclear Information System (INIS)

    Rochet, Nathalie; Sterzing, Florian; Jensen, Alexandra D.; Dinkel, Julien; Herfarth, Klaus K.; Schubert, Kai; Eichbaum, Michael H.; Schneeweiss, Andreas; Sohn, Christof; Debus, Juergen; Harms, Wolfgang

    2010-01-01

    Purpose: To assess the feasibility and toxicity of consolidative intensity-modulated whole abdominal radiotherapy (WAR) after surgery and chemotherapy in high-risk patients with advanced ovarian cancer. Methods and Materials: Ten patients with optimally debulked ovarian cancer International Federation of Gynecology and Obstetrics Stage IIIc were treated in a Phase I study with intensity-modulated WAR up to a total dose of 30 Gy in 1.5-Gy fractions as consolidation therapy after adjuvant carboplatin/taxane chemotherapy. Treatment was delivered using intensity-modulated radiotherapy in a step-and-shoot technique (n = 3) or a helical tomotherapy technique (n = 7). The planning target volume included the entire peritoneal cavity and the pelvic and para-aortal node regions. Organs at risk were kidneys, liver, heart, vertebral bodies, and pelvic bones. Results: Intensity-modulated WAR resulted in an excellent coverage of the planning target volume and an effective sparing of the organs at risk. The treatment was well tolerated, and no severe Grade 4 acute side effects occurred. Common Toxicity Criteria Grade III toxicities were as follows: diarrhea (n = 1), thrombocytopenia (n = 1), and leukopenia (n = 3). Radiotherapy could be completed by all the patients without any toxicity-related interruption. Median follow-up was 23 months, and 4 patients had tumor recurrence (intraperitoneal progression, n = 3; hepatic metastasis, n = 1). Small bowel obstruction caused by adhesions occurred in 3 patients. Conclusions: The results of this Phase I study showed for the first time, to our knowledge, the clinical feasibility of intensity-modulated whole abdominal radiotherapy, which could offer a new therapeutic option for consolidation treatment of advanced ovarian carcinoma after adjuvant chemotherapy in selected subgroups of patients. We initiated a Phase II study to further evaluate the toxicity of this intensive multimodal treatment.

  9. Intensity-modulated whole abdominal radiotherapy after surgery and carboplatin/taxane chemotherapy for advanced ovarian cancer: phase I study.

    Science.gov (United States)

    Rochet, Nathalie; Sterzing, Florian; Jensen, Alexandra D; Dinkel, Julien; Herfarth, Klaus K; Schubert, Kai; Eichbaum, Michael H; Schneeweiss, Andreas; Sohn, Christof; Debus, Juergen; Harms, Wolfgang

    2010-04-01

    To assess the feasibility and toxicity of consolidative intensity-modulated whole abdominal radiotherapy (WAR) after surgery and chemotherapy in high-risk patients with advanced ovarian cancer. Ten patients with optimally debulked ovarian cancer International Federation of Gynecology and Obstetrics Stage IIIc were treated in a Phase I study with intensity-modulated WAR up to a total dose of 30 Gy in 1.5-Gy fractions as consolidation therapy after adjuvant carboplatin/taxane chemotherapy. Treatment was delivered using intensity-modulated radiotherapy in a step-and-shoot technique (n = 3) or a helical tomotherapy technique (n = 7). The planning target volume included the entire peritoneal cavity and the pelvic and para-aortal node regions. Organs at risk were kidneys, liver, heart, vertebral bodies, and pelvic bones. Intensity-modulated WAR resulted in an excellent coverage of the planning target volume and an effective sparing of the organs at risk. The treatment was well tolerated, and no severe Grade 4 acute side effects occurred. Common Toxicity Criteria Grade III toxicities were as follows: diarrhea (n = 1), thrombocytopenia (n = 1), and leukopenia (n = 3). Radiotherapy could be completed by all the patients without any toxicity-related interruption. Median follow-up was 23 months, and 4 patients had tumor recurrence (intraperitoneal progression, n = 3; hepatic metastasis, n = 1). Small bowel obstruction caused by adhesions occurred in 3 patients. The results of this Phase I study showed for the first time, to our knowledge, the clinical feasibility of intensity-modulated whole abdominal radiotherapy, which could offer a new therapeutic option for consolidation treatment of advanced ovarian carcinoma after adjuvant chemotherapy in selected subgroups of patients. We initiated a Phase II study to further evaluate the toxicity of this intensive multimodal treatment.

  10. Optimization of brain metastases radiotherapy with TomoHDA

    Energy Technology Data Exchange (ETDEWEB)

    Yartsev, Slav, E-mail: slav.yartsev@lhsc.on.ca; Bauman, Glenn

    2017-04-01

    An upgrade of the helical tomotherapy technology by introducing variable fan-field width (dynamic jaws) reduced the penumbra in superior-inferior direction for the target. Possible implementation of this upgrade even for the cases of the targets with different dose prescriptions is proposed. An example of brain metastasis in proximity to the optical apparatus in need of the whole brain irradiation of 30 Gy and higher dose to the lesion is considered.

  11. [Position-checking by imaging embarked there tomotherapy and the delegation to the radiology technician].

    Science.gov (United States)

    Autret, A; Choupeaux, D; Le Mée, M

    2016-10-01

    Tomotherapy is a technique of IMRT and IGRT using a linear accelerator and a helical CT-scanner. To reach this targeting of precision, the repositioning of the patient is essential. The use of a contention adapted according to the location of the disease and the morphology of the patient is necessary for the safety of this one and the treatment. Once the patient positioned on the reference table, technicians of imager's team check by the acquisition of helical imagery with the reference CT-scanner the position of the patient, the zone of the PTV and healthy organs in the protected surroundings. At first, adjustment will be made automatically on three planes of the space (axial, sagittal, frontal) and three rotations (pitch, roll and yaw) by the device of treatment, then the technicians of imagery will bring a modification of these recalls manually. After validation, the processing will then be made in complete safety for the patient and the nursing. This check by MVCT is daily before every session of processing. It is made by the technicians of imagery. The radiation oncologist confirms the images at j0, then controls once a week MVCT. Traceability in the file of the patient of the various marks (osseous and\\or soft tissue) necessary for the daily gaps will be noted by this one to delegate to the technicians of imagery the validation of the MVCT before every session. Copyright © 2016. Published by Elsevier SAS.

  12. Measuring dose from radiotherapy treatments in the vicinity of a cardiac pacemaker.

    Science.gov (United States)

    Peet, Samuel C; Wilks, Rachael; Kairn, Tanya; Crowe, Scott B

    2016-12-01

    This study investigated the dose absorbed by tissues surrounding artificial cardiac pacemakers during external beam radiotherapy procedures. The usefulness of out-of-field reference data, treatment planning systems, and skin dose measurements to estimate the dose in the vicinity of a pacemaker was also examined. Measurements were performed by installing a pacemaker onto an anthropomorphic phantom, and using radiochromic film and optically stimulated luminescence dosimeters to measure the dose in the vicinity of the device during the delivery of square fields and clinical treatment plans. It was found that the dose delivered in the vicinity of the cardiac device was unevenly distributed both laterally and anteroposteriorly. As the device was moved distally from the square field, the dose dropped exponentially, in line with out-of-field reference data in the literature. Treatment planning systems were found to substantially underestimate the dose for volumetric modulated arc therapy, helical tomotherapy, and 3D conformal treatments. The skin dose was observed to be either greater or lesser than the dose received at the depth of the device, depending on the treatment site, and so care should be if skin dose measurements are to be used to estimate the dose to a pacemaker. Square field reference data may be used as an upper estimate of absorbed dose per monitor unit in the vicinity of a cardiac device for complex treatments involving multiple gantry angles. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  13. Left-sided breast cancer irradiation using rotational and fixed-field radiotherapy

    International Nuclear Information System (INIS)

    Qi, X. Sharon; Liu, Tian X.; Liu, Arthur K.; Newman, Francis; Rabinovitch, Rachel; Kavanagh, Brian; Hu, Y. Angie

    2014-01-01

    The 3-dimensional conformal radiotherapy (3DCRT) technique is the standard for breast cancer radiotherapy. During treatment planning, not only the coverage of the planning target volume (PTV) but also the minimization of the dose to critical structures, such as the lung, heart, and contralateral breast tissue, need to be considered. Because of the complexity and variations of patient anatomy, more advanced radiotherapy techniques are sometimes desired to better meet the planning goals. In this study, we evaluated external-beam radiation treatment techniques for left breast cancer using various delivery platforms: fixed-field including TomoDirect (TD), static intensity-modulated radiotherapy (sIMRT), and rotational radiotherapy including Elekta volumetric-modulated arc therapy (VMAT) and tomotherapy helical (TH). A total of 10 patients with left-sided breast cancer who did or did not have positive lymph nodes and were previously treated with 3DCRT/sIMRT to the entire breast were selected, their treatment was planned with Monaco VMAT, TD, and TH. Dosimetric parameters including PTV coverage, organ-at-risk (OAR) sparing, dose-volume histograms, and target minimum/maximum/mean doses were evaluated. It is found that for plans providing comparable PTV coverage, the Elekta VMAT plans were generally more inhomogeneous than the TH and TD plans. For the cases with regional node involvement, the average mean doses administered to the heart were 9.2 (± 5.2) and 8.8 (± 3.0) Gy in the VMAT and TH plans compared with 11.9 (± 6.4) and 11.8 (± 9.2) Gy for the 3DCRT and TD plans, respectively, with slightly higher doses given to the contralateral lung or breast or both. On average, the total monitor units for VMAT plans are 11.6% of those TH plans. Our studies have shown that VMAT and TH plans offer certain dosimetric advantages over fixed-field IMRT plans for advanced breast cancer requiring regional nodal treatment. However, for early-stage breast cancer fixed

  14. Monte Carlo simulation of the Tomotherapy treatment unit in the static mode using MC HAMMER, a Monte Carlo tool dedicated to Tomotherapy

    International Nuclear Information System (INIS)

    Sterpin, E; Tomsej, M; Cravens, B; Salvat, F; Ruchala, K; Olivera, G H; Vynckier, S

    2007-01-01

    Helical tomotherapy (HT) is designed to deliver highly modulated IMRT treatments. The concept of HT provides new challenges in MC simulation, because simultaneous movement of the gantry, the couch and the multi-leaf collimator (MLC) must be simulated accurately. However, before accounting for gantry, couch movement and multileaf collimator configurations, high accuracy must be achieved while simulating open static fields (1 x 40, 2.5 x 40 and 5 x 40 cm 2 ). This is performed using MC HAMMER, which is a graphical user interface allowing MC simulation using PENELOPE for various configurations of HT. Since the geometry of the different elements and materials involved in the beam generation are precisely known and defined, the only parameters that need to be tuned on are therefore electron source spot size and electron energy. Beyond the build up region, good agreement (2%/1mm) is achieved for all the field sizes between measurements (ion chamber) and simulations with an electron source energy set to 5.5 MeV. The electron source spot size is modelled as a gaussian distribution with full width half maximum equal to 1.4 mm. This value was chosen to match measured and calculated penumbras in the longitudinal direction

  15. A treatment planning study comparing whole breast radiation therapy against conformal, IMRT and tomotherapy for accelerated partial breast irradiation

    International Nuclear Information System (INIS)

    Oliver, Mike; Chen, Jeff; Wong, Eugene; Van Dyk, Jake; Perera, Francisco

    2007-01-01

    Purpose and background: Conventional early breast cancer treatment consists of a lumpectomy followed by whole breast radiation therapy. Accelerated partial breast irradiation (APBI) is an investigational approach to post-lumpectomy radiation for early breast cancer. The purpose of this study is to compare four external beam APBI techniques, including tomotherapy, with conventional whole breast irradiation for their radiation conformity index, dose homogeneity index, and dose to organs at risk. Methods and materials: Small-field tangents, three-dimensional conformal radiation therapy, intensity-modulated radiation therapy and helical tomotherapy were compared for each of 15 patients (7 right, 8 left). One radiation conformity and two dose homogeneity indices were used to evaluate the dose to the target. The mean dose to organs at risk was also evaluated. Results: All proposed APBI techniques improved the conformity index significantly over whole breast tangents while maintaining dose homogeneity and without a significant increase in dose to organs at risk. Conclusion: The four-field IMRT plan produced the best dosimetric results; however this technique would require appropriate respiratory motion management. An alternative would be to use a four-field conformal technique that is less sensitive to the effects of respiratory motion

  16. An automatic contour propagation method to follow parotid gland deformation during head-and-neck cancer tomotherapy

    International Nuclear Information System (INIS)

    Faggiano, E; Scalco, E; Rizzo, G; Fiorino, C; Broggi, S; Cattaneo, M; Maggiulli, E; Calandrino, R; Dell'Oca, I; Di Muzio, N

    2011-01-01

    We developed an efficient technique to auto-propagate parotid gland contours from planning kVCT to daily MVCT images of head-and-neck cancer patients treated with helical tomotherapy. The method deformed a 3D surface mesh constructed from manual kVCT contours by B-spline free-form deformation to generate optimal and smooth contours. Deformation was calculated by elastic image registration between kVCT and MVCT images. Data from ten head-and-neck cancer patients were considered and manual contours by three observers were included in both kVCT and MVCT images. A preliminary inter-observer variability analysis demonstrated the importance of contour propagation in tomotherapy application: a high variability was reported in MVCT parotid volume estimation (p = 0.0176, ANOVA test) and a larger uncertainty of MVCT contouring compared with kVCT was demonstrated by DICE and volume variability indices (Wilcoxon signed rank test, p -4 for both indices). The performance analysis of our method showed no significant differences between automatic and manual contours in terms of volumes (p > 0.05, in a multiple comparison Tukey test), center-of-mass distances (p = 0.3043, ANOVA test), DICE values (p = 0.1672, Wilcoxon signed rank test) and average and maximum symmetric distances (p = 0.2043, p = 0.8228 Wilcoxon signed rank tests). Results suggested that our contour propagation method could successfully substitute human contouring on MVCT images.

  17. An automatic contour propagation method to follow parotid gland deformation during head-and-neck cancer tomotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Faggiano, E; Scalco, E; Rizzo, G [Istituto di Bioimmagini e Fisiologia Molecolare (IBFM), CNR, Milan (Italy); Fiorino, C; Broggi, S; Cattaneo, M; Maggiulli, E; Calandrino, R [Department of Medical Physics, San Raffaele Scientific Institute, Milan (Italy); Dell' Oca, I; Di Muzio, N, E-mail: fiorino.claudio@hsr.it [Department of Radiotherapy, San Raffaele Scientific Institute, Milan (Italy)

    2011-02-07

    We developed an efficient technique to auto-propagate parotid gland contours from planning kVCT to daily MVCT images of head-and-neck cancer patients treated with helical tomotherapy. The method deformed a 3D surface mesh constructed from manual kVCT contours by B-spline free-form deformation to generate optimal and smooth contours. Deformation was calculated by elastic image registration between kVCT and MVCT images. Data from ten head-and-neck cancer patients were considered and manual contours by three observers were included in both kVCT and MVCT images. A preliminary inter-observer variability analysis demonstrated the importance of contour propagation in tomotherapy application: a high variability was reported in MVCT parotid volume estimation (p = 0.0176, ANOVA test) and a larger uncertainty of MVCT contouring compared with kVCT was demonstrated by DICE and volume variability indices (Wilcoxon signed rank test, p < 10{sup -4} for both indices). The performance analysis of our method showed no significant differences between automatic and manual contours in terms of volumes (p > 0.05, in a multiple comparison Tukey test), center-of-mass distances (p = 0.3043, ANOVA test), DICE values (p = 0.1672, Wilcoxon signed rank test) and average and maximum symmetric distances (p = 0.2043, p = 0.8228 Wilcoxon signed rank tests). Results suggested that our contour propagation method could successfully substitute human contouring on MVCT images.

  18. Angiogenic Blockade and Radiotherapy in Hepatocellular Carcinoma

    International Nuclear Information System (INIS)

    Chi, Kwan-Hwa; Liao, Chao-Sheng; Chang, Chih-Chia; Ko, Hui-Ling; Tsang, Yuk-Wah; Yang, Kuo-Ching; Mehta, Minesh P.

    2010-01-01

    Purpose: We report our preliminary experience of combining sunitinib and helical tomotherapy in patients with advanced HCC. Methods and Materials: Records of patients with advanced hepatocellular carcinoma (HCC) treated with helical tomotherapy and sunitinib after radiation therapy (RT) from March 2007 to August 2008 were retrospectively reviewed. We report acute toxicities, radiologic response, serial α-fetoprotein (AFP) kinetics, and survival. Results: Of 23 evaluable patients, 60% had ≥2 hepatic lesions, extrahepatic disease was present in 5 (21.7%), and all received 2 tablets (25 mg) of sunitinib at least 1 week before, during, and 2 weeks after RT. Thirteen patients continued maintenance sunitinib after RT until disease progression. Hypofractionated RT with a median target dose of 52.5 Gy/15 fractions was delivered. An objective response was achieved in 74% of patients. The 1-year survival rate was 70%, with median survival of 16 months. Multivariate analysis showed that maintenance sunitinib was the most significant factor for survival. The time to progression was 10 months in the maintenance group compared with 4 months in the control group. Eighteen out of 21 patients with elevated AFP (85.7%) had ≥50% decline of AFP within 2 months after RT. There were three episodes of upper gastrointestinal bleeding and one episode of pancreatitis; 10 patients had ≥Grade 2 elevation of liver enzymes, and 15 had ≥Grade 2 thrombocytopenia. Conclusions: These preliminary results suggest that sunitinib and helical tomotherapy yield high Response Evaluation Criteria in Solid Tumors (RECIST) and AFP response rates in advanced HCC with an acceptable safety profile. Maintenance sunitinib after RT potentially prolongs survival. A randomized trial is warranted.

  19. A retrospective comparison of outcome and toxicity of preoperative image-guided intensity-modulated radiotherapy versus conventional pelvic radiotherapy for locally advanced rectal carcinoma

    International Nuclear Information System (INIS)

    Huang, Chun-Ming; Huang, Ming-Yii; Tsai, Hsiang-Lin; Huang, Ching-Wen; Ma, Cheng-Jen; Lin, Chih-Hung; Huang, Chih-Jen; Wang, Jaw-Yuan

    2017-01-01

    The aim of the study was to compare clinical outcomes and toxicity between 3D conformal radiotherapy (3DCRT) and image-guided intensity-modulated radiotherapy (IG-IMRT) administered through helical tomotherapy in locally advanced rectal cancer (LARC) patients receiving preoperative chemoradiotherapy. We reviewed 144 patients with Stage II–III rectal cancer receiving preoperative fluoropyrimidine-based chemoradiotherapy followed by radical resection. Tumor responses following chemoradiotherapy were evaluated using the Dworak tumor regression grade (TRG). Of the 144 patients, 45 received IG-IMRT and 99 received 3DCRT. A significant reduction in Grade 3 or 4 acute gastrointestinal toxicity (IG-IMRT, 6.7%; 3DCRT, 15.1%; P = 0.039) was observed by IG-IMRT. The pathologic complete response (pCR) rate did not differ between the IG-IMRT and the 3DCRT group (17.8% vs 15.1%, P = 0.52). Patients in the IG-IMRT group had the trend of favorable tumor regressions (TRG 3 or 4) compared with those in the 3DCRT group (66.7% vs 43.5%, P = 0.071). The median follow-up was 53 months (range, 18–95 months) in the 3DCRT group and 43 months (range, 17–69 months) in the IG-IMRT group. Four-year overall, disease-free, and local failure–free survival rates of the IG-IMRT and 3DCRT groups were 81.6% and 67.9% (P = 0.12), 53.8% and 51.8% (P = 0.51), and 88% and 75.1% (P = 0.031), respectively. LARC patients treated with preoperative IG-IMRT achieved lower acute gastrointestinal adverse effects and a higher local control rate than those treated with 3DCRT, but there was no prominent difference in distant metastasis rate and overall survival between two treatment modalities.

  20. Recalculation of dose for each fraction of treatment on TomoTherapy.

    Science.gov (United States)

    Thomas, Simon J; Romanchikova, Marina; Harrison, Karl; Parker, Michael A; Bates, Amy M; Scaife, Jessica E; Sutcliffe, Michael P F; Burnet, Neil G

    2016-01-01

    The VoxTox study, linking delivered dose to toxicity requires recalculation of typically 20-37 fractions per patient, for nearly 2000 patients. This requires a non-interactive interface permitting batch calculation with multiple computers. Data are extracted from the TomoTherapy(®) archive and processed using the computational task-management system GANGA. Doses are calculated for each fraction of radiotherapy using the daily megavoltage (MV) CT images. The calculated dose cube is saved as a digital imaging and communications in medicine RTDOSE object, which can then be read by utilities that calculate dose-volume histograms or dose surface maps. The rectum is delineated on daily MV images using an implementation of the Chan-Vese algorithm. On a cluster of up to 117 central processing units, dose cubes for all fractions of 151 patients took 12 days to calculate. Outlining the rectum on all slices and fractions on 151 patients took 7 h. We also present results of the Hounsfield unit (HU) calibration of TomoTherapy MV images, measured over an 8-year period, showing that the HU calibration has become less variable over time, with no large changes observed after 2011. We have developed a system for automatic dose recalculation of TomoTherapy dose distributions. This does not tie up the clinically needed planning system but can be run on a cluster of independent machines, enabling recalculation of delivered dose without user intervention. The use of a task management system for automation of dose calculation and outlining enables work to be scaled up to the level required for large studies.

  1. Intensity modulated radiotherapy for elderly bladder cancer patients

    International Nuclear Information System (INIS)

    Hsieh, Chen-Hsi; Wang, Li-Ying; Hsieh, Yen-Ping; Shueng, Pei-Wei; Chung, Shiu-Dong; Chan, Pei-Hui; Lai, Siu-Kai; Chang, Hsiao-Chun; Hsiao, Chi-Huang; Wu, Le-Jung; Chong, Ngot-Swan; Chen, Yu-Jen

    2011-01-01

    To review our experience and evaluate treatment planning using intensity-modulated radiotherapy (IMRT) and helical tomotherapy (HT) for the treatment of elderly patients with bladder cancer. From November 2006 through November 2009, we enrolled 19 elderly patients with histologically confirmed bladder cancer, 9 in the IMRT and 10 in the HT group. The patients received 64.8 Gy to the bladder with or without concurrent chemotherapy. Conventional 4-field 'box' pelvic radiation therapy (2DRT) plans were generated for comparison. The median patient age was 80 years old (range, 65-90 years old). The median survival was 21 months (5 to 26 months). The actuarial 2-year overall survival (OS) for the IMRT vs. the HT group was 26.3% vs .37.5%, respectively; the corresponding values for disease-free survival were 58.3% vs. 83.3%, respectively; for locoregional progression-free survival (LRPFS), the values were 87.5% vs. 83.3%, respectively; and for metastases-free survival, the values were 66.7% vs. 60.0%, respectively. The 2-year OS rates for T1, 2 vs. T3, 4 were 66.7% vs. 35.4%, respectively (p = 0.046). The 2-year OS rate was poor for those whose RT completion time greater than 8 weeks when compared with the RT completed within 8 wks (37.9% vs. 0%, p = 0.004). IMRT and HT provide good LRPFS with tolerable toxicity for elderly patients with invasive bladder cancer. IMRT and HT dosimetry and organ sparing capability were superior to that of 2DRT, and HT provides better sparing ability than IMRT. The T category and the RT completion time influence OS rate

  2. Intensity modulated radiotherapy for elderly bladder cancer patients

    Directory of Open Access Journals (Sweden)

    Chong Ngot-Swan

    2011-06-01

    Full Text Available Abstract Background To review our experience and evaluate treatment planning using intensity-modulated radiotherapy (IMRT and helical tomotherapy (HT for the treatment of elderly patients with bladder cancer. Methods From November 2006 through November 2009, we enrolled 19 elderly patients with histologically confirmed bladder cancer, 9 in the IMRT and 10 in the HT group. The patients received 64.8 Gy to the bladder with or without concurrent chemotherapy. Conventional 4-field "box" pelvic radiation therapy (2DRT plans were generated for comparison. Results The median patient age was 80 years old (range, 65-90 years old. The median survival was 21 months (5 to 26 months. The actuarial 2-year overall survival (OS for the IMRT vs. the HT group was 26.3% vs .37.5%, respectively; the corresponding values for disease-free survival were 58.3% vs. 83.3%, respectively; for locoregional progression-free survival (LRPFS, the values were 87.5% vs. 83.3%, respectively; and for metastases-free survival, the values were 66.7% vs. 60.0%, respectively. The 2-year OS rates for T1, 2 vs. T3, 4 were 66.7% vs. 35.4%, respectively (p = 0.046. The 2-year OS rate was poor for those whose RT completion time greater than 8 weeks when compared with the RT completed within 8 wks (37.9% vs. 0%, p = 0.004. Conclusion IMRT and HT provide good LRPFS with tolerable toxicity for elderly patients with invasive bladder cancer. IMRT and HT dosimetry and organ sparing capability were superior to that of 2DRT, and HT provides better sparing ability than IMRT. The T category and the RT completion time influence OS rate.

  3. The relationship between the bladder volume and optimal treatment planning in definitive radiotherapy for localized prostate cancer

    International Nuclear Information System (INIS)

    Nakamura, Naoki; Sekiguchi, Kenji; Akahane, Keiko; Shikama, Naoto; Takahashi, Osamu; Hama, Yukihiro; Nakagawa, Keiichi

    2012-01-01

    Background and purpose: There is no current consensus regarding the optimal bladder volumes in definitive radiotherapy for localized prostate cancer. The aim of this study was to clarify the relationship between the bladder volume and optimal treatment planning in radiotherapy for localized prostate cancer. Material and methods: Two hundred and forty-three patients underwent definitive radiotherapy with helical tomotherapy for intermediate- and high-risk localized prostate cancer. The prescribed dose defined as 95 % of the planning target volume (PTV) receiving 100 % of the prescription dose was 76 Gy in 38 fractions. The clinical target volume (CTV) was defined as the prostate with a 5-mm margin and 2 cm of the proximal seminal vesicle. The PTV was defined as the CTV with a 5-mm margin. Treatment plans were optimized to satisfy the dose constraints defined by in-house protocols for PTV and organs at risk (rectum wall, bladder wall, sigmoid colon and small intestine). If all dose constraints were satisfied, the plan was defined as an optimal plan (OP). Results: An OP was achieved with 203 patients (84%). Mean bladder volume (± 1 SD) was 266 ml (± 130 ml) among those with an OP and 214 ml (±130 ml) among those without an OP (p = 0.02). Logistic regression analysis also showed that bladder volumes below 150 ml decreased the possibility of achieving an OP. However, the percentage of patients with an OP showed a plateau effect at bladder volumes above 150 ml. Conclusions. Bladder volume is a significant factor affecting OP rates. However, our results suggest that bladder volumes exceeding 150 ml may not help meet planning dose constraints

  4. Helicity content and tokamak applications of helicity

    International Nuclear Information System (INIS)

    Boozer, A.H.

    1986-05-01

    Magnetic helicity is approximately conserved by the turbulence associated with resistive instabilities of plasmas. To generalize the application of the concept of helicity, the helicity content of an arbitrary bounded region of space will be defined. The definition has the virtues that both the helicity content and its time derivative have simple expressions in terms of the poloidal and toroidal magnetic fluxes, the average toroidal loop voltage and the electric potential on the bounding surface, and the volume integral of E-B. The application of the helicity concept to tokamak plasmas is illustrated by a discussion of so-called MHD current drive, an example of a stable tokamak q profile with q less than one in the center, and a discussion of the possibility of a natural steady-state tokamak due to the bootstrap current coupling to tearing instabilities

  5. Abutment region dosimetry for serial tomotherapy

    International Nuclear Information System (INIS)

    Low, Daniel A.; Mutic, Sasa; Dempsey, James F.; Markman, Jerry; Goddu, S. Murty; Purdy, James A.

    1999-01-01

    Purpose: A commercial intensity modulated radiation therapy system (Corvus, NOMOS Corp.) is presently used in our clinic to generate optimized dose distributions delivered using a proprietary dynamic multileaf collimator (DMLC) (MIMiC) composed of 20 opposed leaf pairs. On our accelerator (Clinac 600C/D, Varian Associates, Inc.) each MIMiC leaf projects to either 1.00 x 0.84 or 1.00 x 1.70 cm 2 (depending on the treatment plan and termed 1 cm or 2 cm mode, respectively). The MIMiC is used to deliver serial (axial) tomotherapy treatment plans, in which the beam is delivered to a nearly cylindrical volume as the DMLC is rotated about the patient. For longer targets, the patient is moved (indexed) between treatments a distance corresponding to the projected leaf width. The treatment relies on precise indexing and a method was developed to measure the precision of indexing devices. A treatment planning study of the dosimetric effects of incorrect patient indexing and concluded that a dose heterogeneity of 10% mm -1 resulted. Because the results may be sensitive to the dose model accuracy, we conducted a measurement-based investigation of the consequences of incorrect indexing using our accelerator. Although the indexing provides an accurate field abutment along the isocenter, due to beam divergence, hot and cold spots will be produced below and above isocenter, respectively, when less than 300 deg. arcs were used. A preliminary study recently determined that for a 290 deg. rotation in 1 cm mode, 15% cold and 7% hot spots were delivered to 7 cm above and below isocenter, respectively. This study completes the earlier work by investigating the dose heterogeneity as a function of position relative to the axis of rotation, arc length, and leaf width. The influence of random daily patient positioning errors is also investigated. Methods and Materials: Treatment plans were generated using 8.0 cm diameter cylindrical target volumes within a homogeneous rectilinear film

  6. Helical type vacuum container

    International Nuclear Information System (INIS)

    Owada, Kimio.

    1989-01-01

    Helical type vacuum containers in the prior art lack in considerations for thermal expansion stresses to helical coils, and there is a possibility of coil ruptures. The object of the present invention is to avoid the rupture of helical coils wound around the outer surface of a vacuum container against heat expansion if any. That is, bellows or heat expansion absorbing means are disposed to a cross section of a helical type vacuum container. With such a constitution, thermal expansion of helical coils per se due to temperature elevation of the coils during electric supply can be absorbed by expansion of the bellows or absorption of the heat expansion absorbing means. Further, this can be attained by arranging shear pins in the direction perpendicular to the bellows axis so that the bellows are not distorted when the helical coils are wound around the helical type vacuum container. (I.S.)

  7. Practical and clinical considerations in Cobalt-60 tomotherapy

    Directory of Open Access Journals (Sweden)

    Joshi Chandra

    2009-01-01

    Full Text Available Cobalt-60 (Co-60 based radiation therapy continues to play a significant role in not only developing countries, where access to radiation therapy is extremely limited, but also in industrialized countries. Howver, technology has to be developed to accommodate modern techniques, in-clud-ing image guided and adaptive radiation therapy (IGART. In this paper we describe some of the practical and clinical considerations for Co-60 based tomotherapy by comparing Co-60 and 6 MV linac-based tomotherapy plans for a head and neck (HandN cancer and a prostate cancer case. The tomotherapy IMRT plans were obtained by modeling a MIMiC binary multi-leaf collimator attached to a Theratron-780c Co-60 unit and a 6 MV linear accelerator (CL2100EX. The EGSnrc/BEAMnrc Monte Carlo (MC code was used for the modeling of the treatment units with the MIMiC collimator and EGSnrc/DOSXYZnrc code was used for beamlet dose data. An in-house inverse treatment planning program was then used to generate optimized tomotherapy dose distributions for the H and N and prostate cases. The dose distributions, cumulative dose area histograms (DAHs and dose difference maps were used to evaluate and compare Co-60 and 6 MV based tomotherapy plans. A quantitative analysis of the dose distributions and dose-volume histograms shows that both Co-60 and 6 MV plans achieve the plan objectives for the targets (CTV and nodes and OARs (spinal cord in HandN case, and rectum in prostate case.

  8. Poster — Thur Eve — 15: Improvements in the stability of the tomotherapy imaging beam

    Energy Technology Data Exchange (ETDEWEB)

    Belec, J [The Ottawa Hospital Cancer Center, Ontario (Canada)

    2014-08-15

    Use of helical TomoTherapy based MVCT imaging for adaptive planning requires the image values (HU) to remain stable over the course of treatment. In the past, the image value stability was suboptimal, which required frequent change to the image value to density calibration curve to avoid dose errors on the order of 2–4%. The stability of the image values at our center was recently improved by stabilizing the dose rate of the machine (dose control servo) and performing daily MVCT calibration corrections. In this work, we quantify the stability of the image values over treatment time by comparing patient treatment image density derived using MVCT and KVCT. The analysis includes 1) MVCT - KVCT density difference histogram, 2) MVCT vs KVCT density spectrum, 3) multiple average profile density comparison and 4) density difference in homogeneous locations. Over two months, the imaging beam stability was compromised several times due to a combination of target wobbling, spectral calibration, target change and magnetron issues. The stability of the image values were analyzed over the same period. Results show that the impact on the patient dose calculation is 0.7% +− 0.6%.

  9. Treatment of folliculitis decalvans using intensity-modulated radiation via tomotherapy

    International Nuclear Information System (INIS)

    Elsayad, Khaled; Kriz, Jan; Haverkamp, Uwe; Eich, Hans Theodor; Plachouri, Kerasia-Maria; Jeskowiak, Antonia; Sunderkoetter, Cord

    2015-01-01

    Folliculitis decalvans (FD) is a form of primary neutrophilic scarring alopecia that is characterized clinically by chronic suppurative folliculitis and often associated with pruritus or even pain. Treatment of FD is often difficult. Herein, we report a case of recalcitrant and painful folliculitis decalvans refractory to antibiotic and anti-inflammatory therapies, which was successfully treated by intensity-modulated radiotherapy (IMRT) in order to irreversibly eliminate hair follicles that prove to be one etiological trigger. A 45-year-old male patient with a refractory FD presented with a crusting suppurative folliculitis and atrophic scarring patches on the scalp associated with pain and pruritus. We attempted relief of symptoms by reducing scalp inflammation and eliminating hair follicles through radiation. We delivered 11.0 Gy in two radiation series using tomotherapy, 5.0 Gy in 5 equivalent fractions as a first radiation course. The symptoms markedly decreased but did not totally disappear. Therefore, we delivered a second radiation series 4 months later with an additional 6 Gy. This led to almost complete epilation on the scalp and abolished pain and pruritus on the capillitium. The patient was regularly followed up until 26 months after radiotherapy. Draining lesions or exudation did not recur. He only experienced discrete hair regrowth in the occipital region with folliculitis 12 months after radiotherapy. These residual lesions are currently treated with laser epilation therapy. A radical approach to eliminating hair follicles by repeated radiation therapy may induce lasting relief of symptoms in chronic suppurative FD associated with persistent trichodynia. (orig.) [de

  10. Treatment of folliculitis decalvans using intensity-modulated radiation via tomotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Elsayad, Khaled; Kriz, Jan; Haverkamp, Uwe; Eich, Hans Theodor [University Hospital of Muenster, Department of Radiation Oncology, Muenster (Germany); Plachouri, Kerasia-Maria; Jeskowiak, Antonia [University Hospital of Muenster, Department of Dermatology, Muenster (Germany); Sunderkoetter, Cord [University Hospital of Muenster, Department of Dermatology, Muenster (Germany); University Hospital of Muenster, Department of Translational Dermatoninfectiology, Muenster (Germany)

    2015-11-15

    Folliculitis decalvans (FD) is a form of primary neutrophilic scarring alopecia that is characterized clinically by chronic suppurative folliculitis and often associated with pruritus or even pain. Treatment of FD is often difficult. Herein, we report a case of recalcitrant and painful folliculitis decalvans refractory to antibiotic and anti-inflammatory therapies, which was successfully treated by intensity-modulated radiotherapy (IMRT) in order to irreversibly eliminate hair follicles that prove to be one etiological trigger. A 45-year-old male patient with a refractory FD presented with a crusting suppurative folliculitis and atrophic scarring patches on the scalp associated with pain and pruritus. We attempted relief of symptoms by reducing scalp inflammation and eliminating hair follicles through radiation. We delivered 11.0 Gy in two radiation series using tomotherapy, 5.0 Gy in 5 equivalent fractions as a first radiation course. The symptoms markedly decreased but did not totally disappear. Therefore, we delivered a second radiation series 4 months later with an additional 6 Gy. This led to almost complete epilation on the scalp and abolished pain and pruritus on the capillitium. The patient was regularly followed up until 26 months after radiotherapy. Draining lesions or exudation did not recur. He only experienced discrete hair regrowth in the occipital region with folliculitis 12 months after radiotherapy. These residual lesions are currently treated with laser epilation therapy. A radical approach to eliminating hair follicles by repeated radiation therapy may induce lasting relief of symptoms in chronic suppurative FD associated with persistent trichodynia. (orig.) [German] Die Folliculitis decalvans (FD) ist eine Form der primaer neutrophilen Alopezie, welche klinisch durch Schmerzen und eitrige Follikel gekennzeichnet ist. Da es bisher kein einheitliches Behandlungskonzept gibt, wird hier ueber eine FD berichtet, welche trotz mehrfacher antibiotischer

  11. Assessment of Parotid Gland Dose Changes During Head and Neck Cancer Radiotherapy Using Daily Megavoltage Computed Tomography and Deformable Image Registration

    International Nuclear Information System (INIS)

    Lee, Choonik; Langen, Katja M.; Lu Weiguo; Haimerl, Jason; Schnarr, Eric; Ruchala, Kenneth J.; Olivera, Gustavo H.; Meeks, Sanford L.; Kupelian, Patrick A.; Shellenberger, Thomas D.; Manon, Rafael R.

    2008-01-01

    Purpose: To analyze changes in parotid gland dose resulting from anatomic changes throughout a course of radiotherapy in a cohort of head-and-neck cancer patients. Methods and Materials: The study population consisted of 10 head-and-neck cancer patients treated definitively with intensity-modulated radiotherapy on a helical tomotherapy unit. A total of 330 daily megavoltage computed tomography images were retrospectively processed through a deformable image registration algorithm to be registered to the planning kilovoltage computed tomography images. The process resulted in deformed parotid contours and voxel mappings for both daily and accumulated dose-volume histogram calculations. The daily and cumulative dose deviations from the original treatment plan were analyzed. Correlations between dosimetric variations and anatomic changes were investigated. Results: The daily parotid mean dose of the 10 patients differed from the plan dose by an average of 15%. At the end of the treatment, 3 of the 10 patients were estimated to have received a greater than 10% higher mean parotid dose than in the original plan (range, 13-42%), whereas the remaining 7 patients received doses that differed by less than 10% (range, -6-8%). The dose difference was correlated with a migration of the parotids toward the high-dose region. Conclusions: The use of deformable image registration techniques and daily megavoltage computed tomography imaging makes it possible to calculate daily and accumulated dose-volume histograms. Significant dose variations were observed as result of interfractional anatomic changes. These techniques enable the implementation of dose-adaptive radiotherapy

  12. Skin-Sparing Radiation Using Intensity-Modulated Radiotherapy After Conservative Surgery in Early-Stage Breast Cancer: A Planning Study

    International Nuclear Information System (INIS)

    Saibishkumar, Elantholi P.; MacKenzie, Marc A.; Severin, Diane; Mihai, Alina; Hanson, John M.Sc.; Daly, Helene; Fallone, Gino; Parliament, Matthew B.; Abdulkarim, Bassam S.

    2008-01-01

    Purpose: To evaluate the feasibility of skin-sparing by configuring it as an organ-at-risk (OAR) while delivering whole-breast intensity-modulated radiotherapy (IMRT) in early breast cancer. Methods and Materials: Archival computed tomography scan images of 14 left-sided early-breast tumor patients who had undergone lumpectomy were selected for this study. Skin was contoured as a 4- to 5-mm strip extending from the patient outline to anterior margin of the breast planning target volume (PTV). Two IMRT plans were generated by the helical tomotherapy approach to deliver 50 Gy in 25 fractions to the breast alone: one with skin dose constraints (skin-sparing plan) and the other without (non-skin-sparing plan). Comparison of the plans was done using a two-sided paired Student t test. Results: The mean skin dose and volume of skin receiving 50 Gy were significantly less with the skin-sparing plan compared with non-skin-sparing plan (42.3 Gy vs. 47.7 Gy and 12.2% vs. 57.8% respectively; p < 0.001). The reduction in skin dose was confirmed by TLD measurements in anthropomorphic phantom using the same plans. Dose-volume analyses for other OARs were similar in both plans. Conclusions: By configuring the skin as an OAR, it is possible to achieve skin dose reduction while delivering whole-breast IMRT without compromising dose profiles to PTV and OARs

  13. Encouraging Early Clinical Outcomes With Helical Tomotherapy–Based Image-Guided Intensity-Modulated Radiation Therapy for Residual, Recurrent, and/or Progressive Benign/Low-Grade Intracranial Tumors: A Comprehensive Evaluation

    International Nuclear Information System (INIS)

    Gupta, Tejpal; Wadasadawala, Tabassum; Master, Zubin; Phurailatpam, Reena; Pai-Shetty, Rajershi; Jalali, Rakesh

    2012-01-01

    Purpose: To report early clinical outcomes of helical tomotherapy (HT)-based image-guided intensity-modulated radiation therapy (IMRT) in brain tumors of varying shape, size, and location. Materials and Methods: Patients with residual, recurrent, and/or progressive low-grade intracranial and skull-base tumors were treated on a prospective protocol of HT-based IMRT and followed clinicoradiologically. Standardized metrics were used for plan evaluation and outcome analysis. Results: Twenty-seven patients with 30 lesions were treated to a median radiotherapy dose of 54 Gy in 30 fractions. All HT plans resulted in excellent target volume coverage with steep dose-gradients. The mean (standard deviation) dose homogeneity index and conformity index was 0.07 (0.05) and 0.71 (0.08) respectively. At first response assessment, 20 of 30 lesions were stable, whereas 9 showed partial regression. One patient with a recurrent clival chordoma though neurologically stable showed imaging-defined progression, whereas another patient with stable disease on serial imaging had sustained neurologic worsening. With a median follow-up of 19 months (interquartile range, 11–26 months), the 2-year clinicoradiological progression-free survival and overall survival was 93.3% and 100% respectively. Conclusions: Careful selection of radiotherapy technique is warranted for benign/low-grade brain tumors to achieve durable local control with minimum long-term morbidity. Large or complex-shaped tumors benefit most from IMRT. Our early clinical experience of HT-based IMRT for brain tumors has been encouraging.

  14. Three-dimensional patient setup errors at different treatment sites measured by the Tomotherapy megavoltage CT

    Energy Technology Data Exchange (ETDEWEB)

    Hui, S.K.; Lusczek, E.; Dusenbery, K. [Univ. of Minnesota Medical School, Minneapolis, MN (United States). Dept. of Therapeutic Radiology - Radiation Oncology; DeFor, T. [Univ. of Minnesota Medical School, Minneapolis, MN (United States). Biostatistics and Informatics Core; Levitt, S. [Univ. of Minnesota Medical School, Minneapolis, MN (United States). Dept. of Therapeutic Radiology - Radiation Oncology; Karolinska Institutet, Stockholm (Sweden). Dept. of Onkol-Patol

    2012-04-15

    Reduction of interfraction setup uncertainty is vital for assuring the accuracy of conformal radiotherapy. We report a systematic study of setup error to assess patients' three-dimensional (3D) localization at various treatment sites. Tomotherapy megavoltage CT (MVCT) images were scanned daily in 259 patients from 2005-2008. We analyzed 6,465 MVCT images to measure setup error for head and neck (H and N), chest/thorax, abdomen, prostate, legs, and total marrow irradiation (TMI). Statistical comparisons of the absolute displacements across sites and time were performed in rotation (R), lateral (x), craniocaudal (y), and vertical (z) directions. The global systematic errors were measured to be less than 3 mm in each direction with increasing order of errors for different sites: H and N, prostate, chest, pelvis, spine, legs, and TMI. The differences in displacements in the x, y, and z directions, and 3D average displacement between treatment sites were significant (p < 0.01). Overall improvement in patient localization with time (after 3-4 treatment fractions) was observed. Large displacement (> 5 mm) was observed in the 75{sup th} percentile of the patient groups for chest, pelvis, legs, and spine in the x and y direction in the second week of the treatment. MVCT imaging is essential for determining 3D setup error and to reduce uncertainty in localization at all anatomical locations. Setup error evaluation should be performed daily for all treatment regions, preferably for all treatment fractions. (orig.)

  15. Image-guided intensity-modulated radiotherapy for refractory bilateral breast cancer in a patient with extensive cutaneous metastasis in the chest and abdominal walls

    Directory of Open Access Journals (Sweden)

    Lu YF

    2016-05-01

    Full Text Available Yueh-Feng Lu,1 Yu-Chin Lin,2 Kuo-Hsin Chen,3,4 Pei-Wei Shueng,1 Hsin-Pei Yeh,1 Chen-Hsi Hsieh1,5,6 1Division of Radiation Oncology, Department of Radiology, 2Division of Oncology and Hematology, Department of Medicine, 3Department of Surgery, Far Eastern Memorial Hospital, New Taipei City, 4Department of Electrical Engineering, Yuan-Ze University, Taoyuan, 5Department of Medicine, 6Institute of Traditional Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan Abstract: Treatment for bilateral breast cancer with chest wall and abdominal skin invasion normally involves conventional radiotherapy (RT; however, conventional RT provides inadequate target volume coverage and excessive treatment of large volumes of normal tissue. Helical tomotherapy (HT has the ability to deliver continuous craniocaudal irradiation that suppresses junction problems and provides good conformity of dose distribution. A 47-year-old female with stage IV bilateral breast cancer with chest wall and pectoralis major muscle invasion, lymphadenopathy, bilateral pleural effusion, and multiple bone metastases received chemotherapy and target therapy beginning in January 2014; 4 months after the initiation of chemotherapy, computed tomography revealed progression of chest and abdominal wall invasion. A total dose of 70.2 Gy was delivered to both breasts, the chest wall, the abdominal wall, and the bilateral supraclavicular nodal areas in 39 fractions via HT. The total planning target volume was 4,533.29 cm3. The percent of lung volume receiving at least 20 Gy (V20 was 28%, 22%, and 25% for the right lung, left lung, and whole lung, respectively. The mean dose to the heart was 8.6 Gy. Follow-up computed tomography revealed complete response after the RT course. Grade 1 dysphagia, weight loss, grade 2 neutropenia, and grade 3 dermatitis were noted during the RT course. Pain score decreased from 6 to 1. No cardiac, pulmonary, liver, or intestinal toxicity

  16. Quality of patient positioning during cerebral tomotherapy irradiation using different mask systems

    Energy Technology Data Exchange (ETDEWEB)

    Leitzen, C.; Wilhelm-Buchstab, T.; Garbe, S.; Luetter, C.; Muedder, T.; Simon, B.; Schild, H.H.; Schueller, H. [Universitaetsklinik Bonn, Radiologische Klinik, FE Strahlentherapie, Bonn (Germany)

    2014-04-15

    Patient immobilization during brain tumor radiotherapy is achieved by employing different mask systems. Two innovative mask systems were developed to minimize the problems of claustrophobic patients. Our aim was to evaluate whether the quality of patient immobilization using the new mask systems was equivalent to the standard mask system currently in use. Thirty-three patients with cerebral target volumes were irradiated using the Hi-Art II tomotherapy system between 2010 and 2012. Each group of 11 patients was fitted with one of the two new mask systems (Crystal {sup registered} or Open Face {sup registered} mask, Orfit) or the standard three-point mask (Raycast {sup registered} -HP, Orfit) and a total of 557 radiotherapy fractions were evaluated. After positioning was checked by MV-CT, the necessary table adjustments were noted. Data were analyzed by comparing the groups, and safety margins were calculated for nonimage-guided irradiation. The mean values of the table adjustments were: (a) lateral (mm): -0.22 (mask 1, standard deviation (σ): 2.15); 1.1 (mask 2, σ: 2.4); -0.64 (mask 3, σ: 2.9); (b) longitudinal (mm): -1 (mask 1, σ: 2.57); -0.5 (mask 2, σ: 4.7); -1.22 (mask 3, σ: 2.52); (c) vertical (mm): 0.62 (mask 1, σ: 0.63); 1.2 (mask 2, σ: 1.0); 0.57 (mask 3, σ: 0.28); (d) roll: 0.35 (mask 1, σ: 0.75); 0 (mask 2, σ: 0.8); 0.02 (mask 3, σ: 1.12). The outcomes suggest necessary safety margins of 5.49-7.38 mm (lateral), 5.4-6.56 mm (longitudinal), 0.82-3.9 mm (vertical), and 1.93-4.5 (roll). There were no significant differences between the groups. The new mask systems improve patient comfort while providing consistent patient positioning. (orig.)

  17. Quality of patient positioning during cerebral tomotherapy irradiation using different mask systems

    International Nuclear Information System (INIS)

    Leitzen, C.; Wilhelm-Buchstab, T.; Garbe, S.; Luetter, C.; Muedder, T.; Simon, B.; Schild, H.H.; Schueller, H.

    2014-01-01

    Patient immobilization during brain tumor radiotherapy is achieved by employing different mask systems. Two innovative mask systems were developed to minimize the problems of claustrophobic patients. Our aim was to evaluate whether the quality of patient immobilization using the new mask systems was equivalent to the standard mask system currently in use. Thirty-three patients with cerebral target volumes were irradiated using the Hi-Art II tomotherapy system between 2010 and 2012. Each group of 11 patients was fitted with one of the two new mask systems (Crystal registered or Open Face registered mask, Orfit) or the standard three-point mask (Raycast registered -HP, Orfit) and a total of 557 radiotherapy fractions were evaluated. After positioning was checked by MV-CT, the necessary table adjustments were noted. Data were analyzed by comparing the groups, and safety margins were calculated for nonimage-guided irradiation. The mean values of the table adjustments were: (a) lateral (mm): -0.22 (mask 1, standard deviation (σ): 2.15); 1.1 (mask 2, σ: 2.4); -0.64 (mask 3, σ: 2.9); (b) longitudinal (mm): -1 (mask 1, σ: 2.57); -0.5 (mask 2, σ: 4.7); -1.22 (mask 3, σ: 2.52); (c) vertical (mm): 0.62 (mask 1, σ: 0.63); 1.2 (mask 2, σ: 1.0); 0.57 (mask 3, σ: 0.28); (d) roll: 0.35 (mask 1, σ: 0.75); 0 (mask 2, σ: 0.8); 0.02 (mask 3, σ: 1.12). The outcomes suggest necessary safety margins of 5.49-7.38 mm (lateral), 5.4-6.56 mm (longitudinal), 0.82-3.9 mm (vertical), and 1.93-4.5 (roll). There were no significant differences between the groups. The new mask systems improve patient comfort while providing consistent patient positioning. (orig.)

  18. A note on helicity

    International Nuclear Information System (INIS)

    Bialynicki-Birula, I.; Newmann, E.T.; Porter, J.; Winicour, J.; Lukacs, B.; Perjes, Z.; Sebestyen, A.

    1981-03-01

    The authors give a formal definition of the helicity operator for integral spin fields, which does not involve their momentum-space decomposition. The discussion is based upon a representation of the Pauli-Lubanski operator in terms of the action on tensor fields by the Killing vectors associated with the generators of the Poincare group. This leads to an identification of the helicity operator with the duality operator defined by the space-time alternating tensor. Helicity eigenstates then correspond to self-dual or anti-self-dual fields, in agreement with usage implicit in the literature. In addiition, the relationship between helicity eigenstates which are intrinsically non-classical, and states of right or left circular polarization in classical electrodynamics are discussed. (author)

  19. Re-Shielding of Cobalt-60 Teletherapy Rooms for Tomotherapy and Conventional Linear Accelerators using Monte Carlo Simulations

    Science.gov (United States)

    Çeçen, Yiğit; Yazgan, Çağrı

    2017-09-01

    Purpose. Nearly all Cobalt-60 teletherapy machines were removed around the world during the last two decades. The remaining ones are being used for experimental purposes. However, the rooms of these teletherapy machines are valuable because of lack of space in radiotherapy clinics. In order to place a new technology treatment machine in one of these rooms, one should re-shield the room since it was designed only for 1.25 MeV gamma beams on average. Mostly, the vendor of the new machine constructs the new shielding of the room using their experience. However, every radiotherapy room has different surrounding work areas and it would be wise to shield the room considering these special conditions. Also, the shield design goal of the clinic may be much lower than the International Atomic Energy Agency (IAEA) or the local association accepts. The study shows re-shielding of a Cobalt-60 room, specific to the clinic, using Monte Carlo simulations. Materials & Methods: First, a 6 MV Tomotherapy machine, then a 10 MV conventional linear accelerator (LINAC) was placed inside the Cobalt-60 teletherapy room. The photon flux outside the room was simulated using Monte Carlo N-Particle (MCNP6.1) code before and after re-shielding. For the Tomotherapy simulation, flux distributions around the machine were obtained from the vendor and implemented as the source of the model. The LINAC model was more generic with the 10 MeV electron source, the tungsten target, first and secondary collimators. The aim of the model was to obtain the maximum (40x40 cm2) open field at the isocenter. Two different simulations were carried out for gantry angles 90o and 270o. The LINAC was placed in the room such that the primary walls were A' (Gantry 270o) and C' (Gantry 90o) (figure 1). The second part of the study was to model the re-shielding of the room for Tomotherapy and for the conventional LINAC, separately. The aim was to investigate the recommended shielding by the vendors. Left side of the room

  20. Daily variations in delivered doses in patients treated with radiotherapy for localized prostate cancer

    International Nuclear Information System (INIS)

    Kupelian, Patrick A.; Langen, Katja M.; Zeidan, Omar A.; Meeks, Sanford L.; Willoughby, Twyla R.; Wagner, Thomas H.; Jeswani, Sam; Ruchala, Kenneth J.; Haimerl, Jason; Olivera, Gustavo H.

    2006-01-01

    Purpose: The aim of this work was to study the variations in delivered doses to the prostate, rectum, and bladder during a full course of image-guided external beam radiotherapy. Methods and Materials: Ten patients with localized prostate cancer were treated with helical tomotherapy to 78 Gy at 2 Gy per fraction in 39 fractions. Daily target localization was performed using intraprostatic fiducials and daily megavoltage pelvic computed tomography (CT) scans, resulting in a total of 390 CT scans. The prostate, rectum, and bladder were manually contoured on each CT by a single physician. Daily dosimetric analysis was performed with dose recalculation. The study endpoints were D95 (dose to 95% of the prostate), rV2 (absolute rectal volume receiving 2 Gy), and bV2 (absolute bladder volume receiving 2 Gy). Results: For the entire cohort, the average D95 (±SD) was 2.02 ± 0.04 Gy (range, 1.79-2.20 Gy). The average rV2 (±SD) was 7.0 ± 8.1 cc (range, 0.1-67.3 cc). The average bV2 (±SD) was 8.7 ± 6.8 cc (range, 0.3-36.8 cc). Unlike doses for the prostate, there was significant daily variation in rectal and bladder doses, mostly because of variations in volume and shape of these organs. Conclusion: Large variations in delivered doses to the rectum and bladder can be documented with daily megavoltage CT scans. Image guidance for the targeting of the prostate, even with intraprostatic fiducials, does not take into account the variation in actual rectal and bladder doses. The clinical impact of techniques that take into account such dosimetric parameters in daily patient set-ups should be investigated

  1. SU-E-T-407: Evaluation of Four Commercial Dosimetry Systems for Routine Patient-Specific Tomotherapy Delivery Quality Assurance

    International Nuclear Information System (INIS)

    Xing, A; Arumugam, S; Deshpande, S; George, A; Holloway, L; Vial, P; Goozee, G

    2014-01-01

    Purpose: The purpose of this project was to evaluate the performance of four commercially available dosimetry systems for Tomotherapy delivery quality assurance (DQA). Methods: Eight clinical patient plans were chosen to represent a range of treatment sites and typical clinical plans. Four DQA plans for each patient plan were created using the TomoTherapy DQA Station (Hi-Art version 4.2.1) on CT images of the ScandiDose Delta4, IBA MatriXX Evolution, PTW Octavius 4D and Sun Nuclear ArcCHECK phantoms. Each detector was calibrated following the manufacture-provided procedure. No angular response correction was applied. All DQA plans for each detector were delivered on the Tomotherapy Hi-Art unit in a single measurement session but on different days. The measured results were loaded into the vendor supplied software for each QA system for comparison with the TPS-calculated dose. The Gamma index was calculated using 3%/3mm, 2%/2mm with 10% dose threshold of maximum TPS calculated dose. Results: Four detector systems showed comparable gamma pass rates for 3%/3m, which is recommended by AAPM TG119 and commonly used within the radiotherapy community. The averaged pass rates ± standard deviation for all DQA plans were (98.35±1.97)% for ArcCHECK, (99.9%±0.87)% for Matrix, (98.5%±5.09)% for Octavius 4D, (98.7%±1.27)% for Delata4. The rank of the gamma pass rate for individual plans was consistent between detectors. Using 2%/2mm Gamma criteria for analysis, the Gamma pass rate decreased on average by 9%, 8%, 6.6% and 5% respectively. Profile and Gamma failure map analysis using the software tools from each dosimetry system indicated that decreased passing rate is mainly due to the threading effect of Tomo plan. Conclusion: Despite the variation in detector type and resolution, phantom geometry and software implementation, the four systems demonstrated similar dosimetric performance, with the rank of the gamma pass rate consistent for the plans considered

  2. Helical CT defecography

    International Nuclear Information System (INIS)

    Ferrando, R.; Fiorini, G.; Beghello, A.; Cicio, G.R.; Derchi, L.E.; Consigliere, M.; Resasco, M.; Tornago, S.

    1999-01-01

    The purpose of this work is to investigate the possible role of Helical CT defecography in pelvic floor disorders by comparing the results of the investigations with those of conventional defecography. The series analyzed consisted of 90 patients, namely 62 women and 28 men, ranging in age 24-82 years. They were all submitted to conventional defecography, and 18 questionable cases were also studied with Helical CT defecography. The conventional examination was performed during the 4 standard phases of resting, squeezing, Valsalva and straining; it is used a remote-control unit. The parameters for Helical CT defecography were: 5 mm beam collimation, pitch 2, 120 KV, 250 m As and 18-20 degrees gantry inclination to acquire coronal images of the pelvic floor. The rectal ampulla was distended with a bolus of 300 mL nonionic iodinated contrast agent (dilution: 3g/cc). The patient wore a napkin and was seated on the table, except for those who could not hold the position and were thus examined supine. Twenty-second helical scans were performed at rest and during evacuation; multiplanar reconstructions were obtained especially on the sagittal plane for comparison with conventional defecographic images. Coronal Helical CT defecography images permitted to map the perineal floor muscles, while sagittal reconstructions provided information on the ampulla and the levator ani. To conclude, Helical CT defecography performed well in study of pelvic floor disorders and can follow conventional defecography especially in questionable cases [it

  3. Therapeutic benefits in grid irradiation on Tomotherapy for bulky, radiation-resistant tumors.

    Science.gov (United States)

    Narayanasamy, Ganesh; Zhang, Xin; Meigooni, Ali; Paudel, Nava; Morrill, Steven; Maraboyina, Sanjay; Peacock, Loverd; Penagaricano, Jose

    2017-08-01

    Spatially fractionated radiation therapy (SFRT or grid therapy) has proven to be effective in management of bulky tumors. The aim of this project is to study the therapeutic ratio (TR) of helical Tomotherapy (HT)-based grid therapy using linear-quadratic cell survival model. HT-based grid (or HT-GRID) plan was generated using a patient-specific virtual grid pattern of high-dose cylindrical regions using MLCs. TR was defined as the ratio of normal tissue surviving fraction (SF) under HT-GRID irradiation to an open debulking field of an equivalent dose that result in the same tumor cell SF. TR was estimated from DVH data on ten HT-GRID patient plans with deep seated, bulky tumor. Dependence of the TR values on radiosensitivity of the tumor cells and prescription dose was analyzed. The mean ± standard deviation (SD) of TR was 4.0 ± 0.7 (range: 3.1-5.5) for the 10 patients with single fraction maximum dose of 20 Gy to GTV assuming a tumor cell SF at 2 Gy (SF2 t ) value of 0·5. In addition, the mean ± SD of TR values for SF2 t values of 0.3 and 0.7 were found to be 1 ± 0.1 and 18.0 ± 5.1, respectively. Reducing the prescription dose to 15 and 10 Gy lowered the respective TR values to 2.0 ± 0.2 and 1.2 ± 0.04 for a SF2 t value of 0.5. HT-GRID therapy demonstrates a significant therapeutic advantage over uniform dose from an open field irradiation for the same tumor cell kill. TR increases with the radioresistance of the tumor cells and with prescription dose.

  4. Use of I.G.R.T. for prostate cancers (O.B.I.-C.B.C.T. VarianTM, ExacTrac BrainLABTM and M.V.C.T. Tomo-therapy)

    International Nuclear Information System (INIS)

    Delpon, G.; Llagostera, C.; Lisbona, A.; Le Blanc, M.; Rio, E.; Supiot, S.; Mahe, M.A.

    2009-01-01

    Introduction: The aim of this work was to report the experience of image-guided radiotherapy at the C.L.C.C. Nantes-Atlantique using three repositioning imaging devices, the ExacTrac (BrainLABTM), the on-board imager cone beam computed tomography (O.B.I.-C.B.C.T.) (Varian TM ) and the M.V.C.T. (Tomotherapy Inc TM ), in the case of prostate external radiotherapy.Material and methods: For each linac and its imaging device, a treatment plan was described. Moreover, studies concerning calculated shifts after imaging sessions were achieved. Using ExacTrac, for eight patients, a study compared daily shifts based on bony anatomy or on implanted markers. Considering mean values of displacements over a course of radiotherapy, dosimetric impact was evaluated. With the O.B.I.-C.B.C.T., two imaging modalities were used, kV-kV (0. and 270.) and C.B.C.T.. Up to now, whatever the images, displacements were calculated using the bony anatomy. For both modalities and for 26 patients, shifts were compared. Since the beginning of the Tomotherapy HiArt use, mega voltage cone tomography (M.V.C.T.) was performed for each session of each patient. For 12 patients, mean displacements were calculated after five fractions. Then the deviations to those values were calculated. This was done to show the relevance of daily M.V.C.T.. Results and conclusion: This work allows us to report the use of three repositioning imaging devices in the radiotherapy department. At least: they provide an efficient positioning tool. And they let us see the future radiotherapy which would probably be the dose-guided radiotherapy. (N.C.)

  5. Helicity, Reconnection, and Dynamo Effects

    International Nuclear Information System (INIS)

    Ji, Hantao

    1998-01-01

    The inter-relationships between magnetic helicity, magnetic reconnection, and dynamo effects are discussed. In laboratory experiments, where two plasmas are driven to merge, the helicity content of each plasma strongly affects the reconnection rate, as well as the shape of the diffusion region. Conversely, magnetic reconnection events also strongly affect the global helicity, resulting in efficient helicity cancellation (but not dissipation) during counter-helicity reconnection and a finite helicity increase or decrease (but less efficiently than dissipation of magnetic energy) during co-helicity reconnection. Close relationships also exist between magnetic helicity and dynamo effects. The turbulent electromotive force along the mean magnetic field (alpha-effect), due to either electrostatic turbulence or the electron diamagnetic effect, transports mean-field helicity across space without dissipation. This has been supported by direct measurements of helicity flux in a laboratory plasma. When the dynamo effect is driven by electromagnetic turbulence, helicity in the turbulent field is converted to mean-field helicity. In all cases, however, dynamo processes conserve total helicity except for a small battery effect, consistent with the observation that the helicity is approximately conserved during magnetic relaxation

  6. Helical-D pinch

    International Nuclear Information System (INIS)

    Schaffer, M.J.

    1997-08-01

    A stabilized pinch configuration is described, consisting of a D-shaped plasma cross section wrapped tightly around a guiding axis. The open-quotes helical-Dclose quotes geometry produces a very large axial (toroidal) transform of magnetic line direction that reverses the pitch of the magnetic lines without the need of azimuthal (poloidal) plasma current. Thus, there is no need of a open-quotes dynamoclose quotes process and its associated fluctuations. The resulting configuration has the high magnetic shear and pitch reversal of the reversed field pinch (RFP). (Pitch = P = qR, where R = major radius). A helical-D pinch might demonstrate good confinement at q << 1

  7. Analysis of target volume motion followed by induced abdominal compression in tomotherapy for prostate cancer

    International Nuclear Information System (INIS)

    Oh, Jeong Hun; Jung, Geon A; Jung, Won Seok; Jo, Jung Young; Kim, Gi Chul; Choi, Tae Kyu

    2014-01-01

    To evaluate the changes of the motion of abdominal cavity between interfraction and intrafraction by using abdominal compression for reducing abdominal motion. 60 MVCT images were obtained before and after tomotherapy from 10 prostate cancer patients over the whole radiotherapy period. Shift values ( X -lateral Y -longitudinal Z -vertical and Roll ) were measured and from it, the correlation of between interfraction set up change and intrafraction target motion was analyzed when applying abdominal compression. The motion changes of interfraction were X- average 0.65±2.32mm, Y-average 1.41±4.83mm, Z-average 0.73± 0.52mm and Roll-average 0.96±0.21mm. The motion changes of intrafraction were X-average 0.15±0.44mm, Y-average 0.13 ±0.44mm, Z-average 0.24±0.64mm and Roll- average 0.1±0.9mm. The average PTV maximum dose difference was minimum for 10% phase and maximum for 70% phase. The average Spain cord maximum dose difference was minimum for 0% phase and maximum for 50% phase. The average difference of V 20 , V 10 , V 5 of Lung show bo certain trend. Abdominal compression can minimize the motion of internal organs and patients. So it is considered to be able to get more ideal dose volume without damage of normal structures from generating margin in small in producing PTV

  8. SU-E-J-174: Adaptive PET-Based Dose Painting with Tomotherapy

    International Nuclear Information System (INIS)

    Darwish, N; Mackie, T; Thomadsen, B

    2014-01-01

    Purpose: PET imaging can be converted into dose prescription directly. Due to the variability of the intensity of PET the image, PET prescription maybe superior over uniform dose prescription. Furthermore, unlike the case in image reconstruction of not knowing the image solution in advance, the prescribed dose is known from a PET image a priori. Therefore, optimum beam orientations are derivable. Methods: We can assume the PET image to be the prescribed dose and invert it to determine the energy fluence. The same method used to reconstruct tissue images from projections could be used to solve the inverse problem of determining beam orientations and modulation patterns from a dose prescription [10]. Unlike standard tomographic reconstruction of images from measured projection profiles, the inversion of the prescribed dose results in photon fluence which may be negative and therefore unphysical. Two-dimensional modulated beams can be modelled in terms of the attenuated or exponential radon transform of the prescribed dose function (assumed to be the PET image in this case), an application of a Ram-Lak filter, and inversion by backprojection. Unlike the case in PET processing, however, the filtered beam obtained from the inversion represents a physical photon fluence. Therefore, a positivity constraint for the fluence (setting negative fluence to zero) must be applied (Brahme et al 1982, Bortfeld et al 1990) Results: Truncating the negative profiles from the PET data results in an approximation of the derivable energy fluence. Backprojection of the deliverable fluence is an approximation of the dose delivered. The deliverable dose is comparable to the original PET image and is similar to the PET image. Conclusion: It is possible to use the PET data or image as a direct indicator of deliverable fluence for cylindrical radiotherapy systems such as TomoTherapy

  9. The physics of radiotherapy X-rays and electrons

    CERN Document Server

    Metcalfe, Peter; Hoban, Peter

    2012-01-01

    The Physics of Radiotherapy X-Rays and Electrons is an updated successor to The Physics of Radiotherapy X-Rays from Linear Accelerators published in 1997. This new volume includes a significant amount of new material, including new chapters on electrons in radiotherapy and IMRT, IGRT, and tomotherapy, which have become key developments in radiation therapy. Also updated from the earlier edition are the physics beam modeling chapters, including Monte Carlo methods, adding those mysterious electrons, as well as discourse on radiobiological modeling including TCP, NTCP, and EUD and the impact of these concepts on plan analysis and inverse planning. This book is intended as a standard reference text for postgraduate radiation oncology medical physics students. It will also be of interest to radiation oncology registrars and residents, dosimetrists, and radiation therapists. The new text contains review questions at the end of each chapter and full bibliographic entries. Fully indexed. Selected questions and ans...

  10. Review of the helicity formalism

    International Nuclear Information System (INIS)

    Barreiro, F.; Cerrada, M.; Fernandez, E.

    1972-01-01

    Our purpose in these notes has been to present a brief and general review of the helicity formalism. We begin by discussing Lorentz invariance, spin and helicity ideas, in section 1 . In section 2 we deal with the construction of relativistic states and scattering amplitudes in the helicity basis and we study their transformation properties under discrete symmetries. Finally we present some more sophisticated topics like kinematical singularities of helicity amplitudes, kinematical constraints and crossing relations 3, 4, 5 respectively. (Author) 8 refs

  11. Helical Confinement Concepts

    Energy Technology Data Exchange (ETDEWEB)

    Beidler, C; Brakel, R; Burhenn, R; Dinklage, A; Erckmann, V; Feng, Y; Geiger, J; Hartmann, D; Hirsch, M; Jaenicke, R; Koenig, R; Laqua, H P; Maassberg, H; Wagner, F; Weller, A; Wobig, H [Max-Planck Institut fuer Plasmaphysik, EURATOM Association, Greifswald (Germany)

    2012-09-15

    Stellarators, conceived 1951 by Lyman Spitzer in Princeton, are toroidal devices that confine a plasma in a magnetic field which originates from currents in coils outside the plasma. A plasma current driven by external means, for example by an ohmic transformer, is not required for confinement. Supplying the desired poloidal field component by external coils leads to a helically structured plasma topology. Thus stellarators - or helical confinement devices - are fully three-dimensional in contrast to the toroidal (rotational) symmetry of tokamaks. As stellarators can be free of an inductive current, whose radial distribution depends on the plasma parameters, their equilibrium must not be established via the evolving plasma itself, but to a first order already given by the vacuum magnetic field. They do not need an active control (like positional feedback) and therefore cannot suffer from its failure. The outstanding conceptual advantage of stellarators is the potential of steady state plasma operation without current drive. As there is no need for current drive, the recirculating power is expected to be smaller than in equivalent tokamaks. The lack of a net current avoids current driven instabilities; specifically, no disruptions, no resistive wall modes and no conventional or neoclassical tearing modes appear. Second order pressure-driven currents (Pfirsch-Schlueter, bootstrap) exist but they can be modified and even minimized by the magnetic design. The magnetic configuration of helical devices naturally possesses a separatrix, which allows the implementation of a helically structured divertor for exhaust and impurity control. (author)

  12. Calculation of the structural shielding of the radiotherapy treatment room equipped with a linear accelerator type Tomo therapy Hi-Art in the Oncology Center of Chihuahua, Mexico; Calculo del blindaje estructural de la sala de tratamiento de radioterapia equipada con un acelerador lineal del tipo Tomotherapy Hi-Art en el Centro Oncologico de Chihuahua, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Caballero G, C. A. [Southwest Oncology Centers, North Civic Center Plaza No. 2926, Scottsdale, Arizona (United States); Plascencia, J. C. [Centro Oncologico Louis and Lucille Grado, Republica del Peru No. 102-5, Col. Americas, Aguascalientes (Mexico); Vargas V, M. X.; Toledo J, P., E-mail: cabshm@msn.co [Centro Oncologico de Chihuahua, Hacienda de la Esperanza No. 6304, Fracc. Cima Comercial, Chihuahua (Mexico)

    2010-09-15

    The helicoid tomo therapy is an external radiotherapy system of modulated intensity, guided by image, in which the radiation is imparted to the patient using a narrow radiation beam in helicoid form, in a similar way to the scanning process with a computerized tomography. The tomo therapy equipment (Tomo Therapy Hi-Art) consists in an electrons linear accelerator with acceleration voltages of 6 MV for treatment and 3.5 MV for image, coupled to a ring that turn around the patient as this is transferred through this ring in perpendicular sense to the radiation beam. The radiation beam is narrow because has the maximum size of 5 x 40 cm{sup 2} in the isocenter. The intensity modulation of the beam is carried out with a binary dynamic collimator of 64 crisscross sheets, and the guide by image though a system of megavoltage computerized tomography. Opposed to the radiation beam, also coupled to the rotational ring, a group of lead plates exists with a total thickness of 13 cm that acts as barrier of the primary radiation beam. The special configuration of the tomography equipment makes to have the following characteristics: 1) the presence of the lead barrier of the equipment reduces the intensity of the primary beam that reaches the bunker walls in considerable way, 2) the disperse and leakage radiations are increased with regard to a conventional accelerator due to the increase in the necessary irradiation time to produce modulated intensity fields by means of the narrow radiation beam. These special characteristics of the tomo therapy equipment make that particularities exist in the application of the formulations for structural shielding calculations that appears in the NCRP reports 49, NCRP 151 and IAEA-SRS-47. For this reason, several researches have development analytic models based on geometric considerations of continuous rotation of the equipment ring to determine the shielding requirements for the primary beam, the dispersed and leakage radiation in tomo

  13. Monte Carlo-based simulation of dynamic jaws tomotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Sterpin, E.; Chen, Y.; Chen, Q.; Lu, W.; Mackie, T. R.; Vynckier, S. [Department of Molecular Imaging, Radiotherapy and Oncology, Universite Catholique de Louvain, 54 Avenue Hippocrate, 1200 Brussels, Belgium and Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin 53705 (United States); TomoTherapy Inc., 1240 Deming Way, Madison, Wisconsin 53717 (United States); 21 Century Oncology., 1240 D' onofrio, Madison, Wisconsin 53719 (United States); TomoTherapy Inc., 1240 Deming Way, Madison, Wisconsin 53717 and Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin 53705 (United States); Department of Radiotherapy and Oncology, Universite Catholique de Louvain, St-Luc University Hospital, 10 Avenue Hippocrate, 1200 Brussels (Belgium)

    2011-09-15

    Purpose: Original TomoTherapy systems may involve a trade-off between conformity and treatment speed, the user being limited to three slice widths (1.0, 2.5, and 5.0 cm). This could be overcome by allowing the jaws to define arbitrary fields, including very small slice widths (<1 cm), which are challenging for a beam model. The aim of this work was to incorporate the dynamic jaws feature into a Monte Carlo (MC) model called TomoPen, based on the MC code PENELOPE, previously validated for the original TomoTherapy system. Methods: To keep the general structure of TomoPen and its efficiency, the simulation strategy introduces several techniques: (1) weight modifiers to account for any jaw settings using only the 5 cm phase-space file; (2) a simplified MC based model called FastStatic to compute the modifiers faster than pure MC; (3) actual simulation of dynamic jaws. Weight modifiers computed with both FastStatic and pure MC were compared. Dynamic jaws simulations were compared with the convolution/superposition (C/S) of TomoTherapy in the ''cheese'' phantom for a plan with two targets longitudinally separated by a gap of 3 cm. Optimization was performed in two modes: asymmetric jaws-constant couch speed (''running start stop,'' RSS) and symmetric jaws-variable couch speed (''symmetric running start stop,'' SRSS). Measurements with EDR2 films were also performed for RSS for the formal validation of TomoPen with dynamic jaws. Results: Weight modifiers computed with FastStatic were equivalent to pure MC within statistical uncertainties (0.5% for three standard deviations). Excellent agreement was achieved between TomoPen and C/S for both asymmetric jaw opening/constant couch speed and symmetric jaw opening/variable couch speed, with deviations well within 2%/2 mm. For RSS procedure, agreement between C/S and measurements was within 2%/2 mm for 95% of the points and 3%/3 mm for 98% of the points, where dose is

  14. TomoTherapy MLC verification using exit detector data

    International Nuclear Information System (INIS)

    Chen Quan; Westerly, David; Fang Zhenyu; Sheng, Ke; Chen Yu

    2012-01-01

    Purpose: Treatment delivery verification (DV) is important in the field of intensity modulated radiation therapy (IMRT). While IMRT and image guided radiation therapy (IGRT), allow us to create more conformal plans and enables the use of tighter margins, an erroneously executed plan can have detrimental effects on the treatment outcome. The purpose of this study is to develop a DV technique to verify TomoTherapy's multileaf collimator (MLC) using the onboard mega-voltage CT detectors. Methods: The proposed DV method uses temporal changes in the MVCT detector signal to predict actual leaf open times delivered on the treatment machine. Penumbra and scattered radiation effects may produce confounding results when determining leaf open times from the raw detector data. To reduce the impact of the effects, an iterative, Richardson-Lucy (R-L) deconvolution algorithm is applied. Optical sensors installed on each MLC leaf are used to verify the accuracy of the DV technique. The robustness of the DV technique is examined by introducing different attenuation materials in the beam. Additionally, the DV technique has been used to investigate several clinical plans which failed to pass delivery quality assurance (DQA) and was successful in identifying MLC timing discrepancies as the root cause. Results: The leaf open time extracted from the exit detector showed good agreement with the optical sensors under a variety of conditions. Detector-measured leaf open times agreed with optical sensor data to within 0.2 ms, and 99% of the results agreed within 8.5 ms. These results changed little when attenuation was added in the beam. For the clinical plans failing DQA, the dose calculated from reconstructed leaf open times played an instrumental role in discovering the root-cause of the problem. Throughout the retrospective study, it is found that the reconstructed dose always agrees with measured doses to within 1%. Conclusions: The exit detectors in the TomoTherapy treatment systems

  15. Monte Carlo-based simulation of dynamic jaws tomotherapy

    International Nuclear Information System (INIS)

    Sterpin, E.; Chen, Y.; Chen, Q.; Lu, W.; Mackie, T. R.; Vynckier, S.

    2011-01-01

    Purpose: Original TomoTherapy systems may involve a trade-off between conformity and treatment speed, the user being limited to three slice widths (1.0, 2.5, and 5.0 cm). This could be overcome by allowing the jaws to define arbitrary fields, including very small slice widths (<1 cm), which are challenging for a beam model. The aim of this work was to incorporate the dynamic jaws feature into a Monte Carlo (MC) model called TomoPen, based on the MC code PENELOPE, previously validated for the original TomoTherapy system. Methods: To keep the general structure of TomoPen and its efficiency, the simulation strategy introduces several techniques: (1) weight modifiers to account for any jaw settings using only the 5 cm phase-space file; (2) a simplified MC based model called FastStatic to compute the modifiers faster than pure MC; (3) actual simulation of dynamic jaws. Weight modifiers computed with both FastStatic and pure MC were compared. Dynamic jaws simulations were compared with the convolution/superposition (C/S) of TomoTherapy in the ''cheese'' phantom for a plan with two targets longitudinally separated by a gap of 3 cm. Optimization was performed in two modes: asymmetric jaws-constant couch speed (''running start stop,'' RSS) and symmetric jaws-variable couch speed (''symmetric running start stop,'' SRSS). Measurements with EDR2 films were also performed for RSS for the formal validation of TomoPen with dynamic jaws. Results: Weight modifiers computed with FastStatic were equivalent to pure MC within statistical uncertainties (0.5% for three standard deviations). Excellent agreement was achieved between TomoPen and C/S for both asymmetric jaw opening/constant couch speed and symmetric jaw opening/variable couch speed, with deviations well within 2%/2 mm. For RSS procedure, agreement between C/S and measurements was within 2%/2 mm for 95% of the points and 3%/3 mm for 98% of the points, where dose is greater than 30% of the prescription dose (gamma analysis

  16. Concurrent image-guided intensity modulated radiotherapy and chemotherapy following neoadjuvant chemotherapy for locally advanced nasopharyngeal carcinoma

    International Nuclear Information System (INIS)

    Shueng, Pei-Wei; Hsieh, Chen-Hsi; Shen, Bing-Jie; Wu, Le-Jung; Liao, Li-Jen; Hsiao, Chi-Huang; Lin, Yu-Chin; Cheng, Po-Wen; Lo, Wu-Chia; Jen, Yee-Min

    2011-01-01

    To evaluate the experience of induction chemotherapy followed by concurrent chemoradiationwith helical tomotherapy (HT) for nasopharyngeal carcinoma (NPC). Between August 2006 and December 2009, 28 patients with pathological proven nonmetastatic NPC were enrolled. All patients were staged as IIB-IVB. Patients were first treated with 2 to 3 cycles of induction chemotherapy with EP-HDFL (Epirubicin, Cisplatin, 5-FU, and Leucovorin). After induction chemotherapy, weekly based PFL was administered concurrent with HT. Radiation consisted of 70 Gy to the planning target volumes of the primary tumor plus any positive nodal disease using 2 Gy per fraction. After completion of induction chemotherapy, the response rates for primary and nodal disease were 96.4% and 80.8%, respectively. With a median follow-up after 33 months (Range, 13-53 months), there have been 2 primary and 1 nodal relapse after completion of radiotherapy. The estimated 3-year progression-free rates for local, regional, locoregional and distant metastasis survival rate were 92.4%, 95.7%, 88.4%, and 78.0%, respectively. The estimated 3-year overall survival was 83.5%. Acute grade 3, 4 toxicities for xerostomia and dermatitis were only 3.6% and 10.7%, respectively. HT for locoregionally advanced NPC is feasible and effective in regard to locoregional control with high compliance, even after neoadjuvant chemotherapy. None of out-field or marginal failure noted in the current study confirms the potential benefits of treating NPC patients by image-guided radiation modality. A long-term follow-up study is needed to confirm these preliminary findings

  17. Coulomb double helical structure

    Science.gov (United States)

    Kamimura, Tetsuo; Ishihara, Osamu

    2012-01-01

    Structures of Coulomb clusters formed by dust particles in a plasma are studied by numerical simulation. Our study reveals the presence of various types of self-organized structures of a cluster confined in a prolate spheroidal electrostatic potential. The stable configurations depend on a prolateness parameter for the confining potential as well as on the number of dust particles in a cluster. One-dimensional string, two-dimensional zigzag structure and three-dimensional double helical structure are found as a result of the transition controlled by the prolateness parameter. The formation of stable double helical structures resulted from the transition associated with the instability of angular perturbations on double strings. Analytical perturbation study supports the findings of numerical simulations.

  18. Helically linked mirror arrangement

    International Nuclear Information System (INIS)

    Ranjan, P.

    1986-08-01

    A scheme is described for helical linking of mirror sections, which endeavors to combine the better features of toroidal and mirror devices by eliminating the longitudinal loss of mirror machines, having moderately high average β and steady state operation. This scheme is aimed at a device, with closed magnetic surfaces having rotational transform for equilibrium, one or more axisymmetric straight sections for reduced radial loss, a simple geometrical axis for the links and an overall positive magnetic well depth for stability. We start by describing several other attempts at linking of mirror sections, made both in the past and the present. Then a description of our helically linked mirror scheme is given. This example has three identical straight sections connected by three sections having helical geometric axes. A theoretical analysis of the magnetic field and single-particle orbits in them leads to the conclusion that most of the passing particles would be confined in the device and they would have orbits independent of pitch angle under certain conditions. Numerical results are presented, which agree well with the theoretical results as far as passing particle orbits are concerned

  19. Treatment verification with megavoltage electronic portal imaging applied to the tomotherapy concept

    International Nuclear Information System (INIS)

    Hesse, B.-M.; Spies, L.; Groh, B.; Doll, J.; Haering, P.; Hoever, K. H.

    1997-01-01

    Purpose: A new treatment strategy called Tomotherapy, introduced by T. R. Mackie et al. in 1993, was designed to perform a dynamic conformal treatment technique in precision radiotherapy. This technique delivers sliced intensity-modulated radiation fields to achieve best tumor control while sparing neighbouring sensitive normal tissue and organs at risk. The beam continuously revolves around the patient similarly to a spiral-CT while the patient is moved through the bore of the gantry. As a first step towards the realization of such a concept with a linear accelerator (Siemens Mevatron Experimental) used in clinical routine, we focused on treatment setup and dose verification. In tomotherapy, an actual CT data set is needed for patient positioning and for the verification of the absorbed dose, also, the dose transmitted through the patient must be known. This makes possible both routine tomographic treatment setup verification and tomographic dose reconstruction of the actual delivered dose. Materials and Methods: All measurements were performed with a megavoltage electronic portal imaging device of Wellhoefer TM (BIS-710). The BIS-710 detector is based on a scintillation foil and contains a camera for 10-bit digital data output. The dimension of the detector plane is 512 x 512 pixels with a pixel size of 0.6 mm in each direction. The BIS-710 was developed especially for quantitative dose measuring, whereas most of the existing Portal Imaging Systems are used for image display only. To examine the properties of the BIS-710 concerning tomographical reconstruction with a therapeutic 6 MV X-ray beam, a tissue-equivalent Alderson head phantom was rotated stepwise across a stationary beam between the collimator and the detector plane. The influence of scattering can be estimated by comparing measurements which were taken with a homogeneous phantom which is invariant under rotation with a calculated exit dose distribution using a simple exponential law for the

  20. SU-E-T-372: Dosimetric Comparison of Craniospinal Irradiation Using Different Tomotherapy Techniques

    International Nuclear Information System (INIS)

    Zhang, X; Penagaricano, J; Han, E; Liang, X; Morrill, S; Hardee, M; Gupta, S; Vaneerat, R

    2014-01-01

    Purpose: TomoHDA can treat with fixed jaws, dynamic jaws, and fixed gantry using either 3DCRT or IMRT. This study compares PTV coverage, OAR sparing, and beam-on-time (BOT) among these techniques for craniospinal irradiation (CSI). Methods: This study includes ten CSI patients treated to 23.4 Gy/13 fractions with Hi-Art 3.0 unit (HT-IMRT fixed 5 cm jaw). New plans were regenerated with 5 cm jaw for TomoHDA Hi-Art 5.0 using dynamic jaw (HD-IMRT), TomoDirect-IMRT (TD-IMRT), and Helical Tomotherapy 3DCRT (HT-3DCRT using 5 cm and 2.5 cm jaws with various pitches). Studied parameters include PTV mean dose, D95 (dose covering 95% of PTV), Paddick's conformity index (CI) and homogeneity index (HI – standard deviation of PTV dose/average PTV dose), BOT, and average OAR doses. Results: PTV coverage from these techniques were comparable (p>0.05). The main differences were in OAR sparing; HDIMRT reduced more OAR doses for lenses, bladder and rectum compared to HT-IMRT. For the sparing of visceral organs: liver, lung, heart, and kidneys, the three IMRT techniques gave comparable results. HD-IMRT gave best heart sparing; HT-IMRT best kidney sparing. Liver and lung doses were best reduced by TD-IMRT. All three IMRT techniques gave comparable BOT. OARs sparing was achieved for jaw size of 2.5 cm. HI was also improved but with doubling of BOT. Increasing the pitch number from 0.2 to 0.43 produced no significant improvement in OAR sparing but CI and HI did improve. Conclusion: HT-3DCRT, HT-IMRT, HD-IMRT or TD-IMRT techniques give comparable PTV coverage but the three IMRT plans better spared OARs compared with 3DCRT plans. Dynamic jaw plan is superior to fixed jaw plan to spare more OAR doses at field edge. TD-IMRT cannot reduce BOT for CSI patient but for sparing certain OAR, TD-IMRT may be used to avoid the beam going through the structures of interest

  1. 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

  2. Analysis of Daily Setup Variation With Tomotherapy Megavoltage Computed Tomography

    International Nuclear Information System (INIS)

    Zhou Jining; Uhl, Barry; Dewit, Kelly; Young, Mark; Taylor, Brian; Fei Dingyu; Lo, Y-C

    2010-01-01

    The purpose of this study was to evaluate different setup uncertainties for various anatomic sites with TomoTherapy (registered) pretreatment megavoltage computed tomography (MVCT) and to provide optimal margin guidelines for these anatomic sites. Ninety-two patients with tumors in head and neck (HN), brain, lung, abdominal, or prostate regions were included in the study. MVCT was used to verify patient position and tumor target localization before each treatment. With the anatomy registration tool, MVCT provided real-time tumor shift coordinates relative to the positions where the simulation CT was performed. Thermoplastic facemasks were used for HN and brain treatments. Vac-Lok TM cushions were used to immobilize the lower extremities up to the thighs for prostate patients. No respiration suppression was administered for lung and abdomen patients. The interfractional setup variations were recorded and corrected before treatment. The mean interfractional setup error was the smallest for HN among the 5 sites analyzed. The average 3D displacement in lateral, longitudinal, and vertical directions for the 5 sites ranged from 2.2-7.7 mm for HN and lung, respectively. The largest movement in the lung was 2.0 cm in the longitudinal direction, with a mean error of 6.0 mm and standard deviation of 4.8 mm. The mean interfractional rotation variation was small and ranged from 0.2-0.5 deg., with the standard deviation ranging from 0.7-0.9 deg. Internal organ displacement was also investigated with a posttreatment MVCT scan for HN, lung, abdomen, and prostate patients. The maximum 3D intrafractional displacement across all sites was less than 4.5 mm. The interfractional systematic errors and random errors were analyzed and the suggested margins for HN, brain, prostate, abdomen, and lung in the lateral, longitudinal, and vertical directions were between 4.2 and 8.2 mm, 5.0 mm and 12.0 mm, and 1.5 mm and 6.8 mm, respectively. We suggest that TomoTherapy (registered) pretreatment

  3. Analysis of daily setup variation with tomotherapy megavoltage computed tomography.

    Science.gov (United States)

    Zhou, Jining; Uhl, Barry; Dewit, Kelly; Young, Mark; Taylor, Brian; Fei, Ding-Yu; Lo, Yeh-Chi

    2010-01-01

    The purpose of this study was to evaluate different setup uncertainties for various anatomic sites with TomoTherapy pretreatment megavoltage computed tomography (MVCT) and to provide optimal margin guidelines for these anatomic sites. Ninety-two patients with tumors in head and neck (HN), brain, lung, abdominal, or prostate regions were included in the study. MVCT was used to verify patient position and tumor target localization before each treatment. With the anatomy registration tool, MVCT provided real-time tumor shift coordinates relative to the positions where the simulation CT was performed. Thermoplastic facemasks were used for HN and brain treatments. Vac-Lok cushions were used to immobilize the lower extremities up to the thighs for prostate patients. No respiration suppression was administered for lung and abdomen patients. The interfractional setup variations were recorded and corrected before treatment. The mean interfractional setup error was the smallest for HN among the 5 sites analyzed. The average 3D displacement in lateral, longitudinal, and vertical directions for the 5 sites ranged from 2.2-7.7 mm for HN and lung, respectively. The largest movement in the lung was 2.0 cm in the longitudinal direction, with a mean error of 6.0 mm and standard deviation of 4.8 mm. The mean interfractional rotation variation was small and ranged from 0.2-0.5 degrees, with the standard deviation ranging from 0.7-0.9 degrees. Internal organ displacement was also investigated with a posttreatment MVCT scan for HN, lung, abdomen, and prostate patients. The maximum 3D intrafractional displacement across all sites was less than 4.5 mm. The interfractional systematic errors and random errors were analyzed and the suggested margins for HN, brain, prostate, abdomen, and lung in the lateral, longitudinal, and vertical directions were between 4.2 and 8.2 mm, 5.0 mm and 12.0 mm, and 1.5 mm and 6.8 mm, respectively. We suggest that TomoTherapy pretreatment MVCT can be used to

  4. TomoTherapy MLC verification using exit detector data

    Energy Technology Data Exchange (ETDEWEB)

    Chen Quan; Westerly, David; Fang Zhenyu; Sheng, Ke; Chen Yu [TomoTherapy Inc., 1240 Deming Way, Madison, Wisconsin 53717 (United States); Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado 80045 (United States); Xinghua Cancer Hospital, Xinghua, Jiangsu 225700 (China); Department of Radiation Oncology, University of California-Los Angeles, Los Angeles, California 90095 (United States); TomoTherapy Inc., 1240 Deming Way, Madison, Wisconsin 53717 (United States)

    2012-01-15

    Purpose: Treatment delivery verification (DV) is important in the field of intensity modulated radiation therapy (IMRT). While IMRT and image guided radiation therapy (IGRT), allow us to create more conformal plans and enables the use of tighter margins, an erroneously executed plan can have detrimental effects on the treatment outcome. The purpose of this study is to develop a DV technique to verify TomoTherapy's multileaf collimator (MLC) using the onboard mega-voltage CT detectors. Methods: The proposed DV method uses temporal changes in the MVCT detector signal to predict actual leaf open times delivered on the treatment machine. Penumbra and scattered radiation effects may produce confounding results when determining leaf open times from the raw detector data. To reduce the impact of the effects, an iterative, Richardson-Lucy (R-L) deconvolution algorithm is applied. Optical sensors installed on each MLC leaf are used to verify the accuracy of the DV technique. The robustness of the DV technique is examined by introducing different attenuation materials in the beam. Additionally, the DV technique has been used to investigate several clinical plans which failed to pass delivery quality assurance (DQA) and was successful in identifying MLC timing discrepancies as the root cause. Results: The leaf open time extracted from the exit detector showed good agreement with the optical sensors under a variety of conditions. Detector-measured leaf open times agreed with optical sensor data to within 0.2 ms, and 99% of the results agreed within 8.5 ms. These results changed little when attenuation was added in the beam. For the clinical plans failing DQA, the dose calculated from reconstructed leaf open times played an instrumental role in discovering the root-cause of the problem. Throughout the retrospective study, it is found that the reconstructed dose always agrees with measured doses to within 1%. Conclusions: The exit detectors in the TomoTherapy treatment

  5. Evaluation of radiosurgery techniques–Cone-based linac radiosurgery vs tomotherapy-based radiosurgery

    Energy Technology Data Exchange (ETDEWEB)

    Yip, Ho Yin, E-mail: hoyinyip@yahoo.com.hk [Department of Radiotherapy, Hong Kong Sanatorium and Hospital, Happy Valley, Hong Kong (China); Mui, Wing Lun A.; Lee, Joseph W.Y.; Fung, Winky Wing Ki; Chan, Jocelyn M.T.; Chiu, G. [Department of Radiotherapy, Hong Kong Sanatorium and Hospital, Happy Valley, Hong Kong (China); Law, Maria Y.Y. [Medical Physics and Research Department, Hong Kong Sanatorium and Hospital, Happy Valley, Hong Kong (China)

    2013-07-01

    Performances of radiosurgery of intracranial lesions between cone-based Linac system and Tomotherapy-based system were compared in terms of dosimetry and time. Twelve patients with single intracranial lesion treated with cone-based Linac radiosurgery system from 2005 to 2009 were replanned for Tomotherapy-based radiosurgery treatment. The conformity index, homogeneity index (HI), and gradient score index (GSI) of each case was calculated. The Wilcoxon matched-pair test was used to compare the 3 indices between both systems. The cases with regular target (n = 6) and those with irregular target (n = 6) were further analyzed separately. The estimated treatment time between both systems was also compared. Significant differences were found in HI (p = 0.05) and in GSI (p = 0.03) for the whole group. Cone-based radiosurgery was better in GSI whereas Tomotherapy-based radiosurgery was better in HI. Cone-based radiosurgery was better in conformity index (p = 0.03) and GSI (p = 0.03) for regular targets, whereas Tomotherapy-based radiosurgery system performed significantly better in HI (p = 0.03) for irregular targets. The estimated total treatment time for Tomotherapy-based radiosurgery ranged from 24 minutes to 35 minutes, including 15 minutes of pretreatment megavoltage computed tomography (MVCT) and image registration, whereas that for cone-based radiosurgery ranged from 15 minutes for 1 isocenter to 75 minutes for 5 isocenters. As a rule of thumb, Tomotherapy-based radiosurgery system should be the first-line treatment for irregular lesions because of better dose homogeneity and shorter treatment time. Cone-based Linac radiosurgery system should be the treatment of choice for regular targets because of the better dose conformity, rapid dose fall-off, and reasonable treatment time.

  6. Evaluation of radiosurgery techniques–Cone-based linac radiosurgery vs tomotherapy-based radiosurgery

    International Nuclear Information System (INIS)

    Yip, Ho Yin; Mui, Wing Lun A.; Lee, Joseph W.Y.; Fung, Winky Wing Ki; Chan, Jocelyn M.T.; Chiu, G.; Law, Maria Y.Y.

    2013-01-01

    Performances of radiosurgery of intracranial lesions between cone-based Linac system and Tomotherapy-based system were compared in terms of dosimetry and time. Twelve patients with single intracranial lesion treated with cone-based Linac radiosurgery system from 2005 to 2009 were replanned for Tomotherapy-based radiosurgery treatment. The conformity index, homogeneity index (HI), and gradient score index (GSI) of each case was calculated. The Wilcoxon matched-pair test was used to compare the 3 indices between both systems. The cases with regular target (n = 6) and those with irregular target (n = 6) were further analyzed separately. The estimated treatment time between both systems was also compared. Significant differences were found in HI (p = 0.05) and in GSI (p = 0.03) for the whole group. Cone-based radiosurgery was better in GSI whereas Tomotherapy-based radiosurgery was better in HI. Cone-based radiosurgery was better in conformity index (p = 0.03) and GSI (p = 0.03) for regular targets, whereas Tomotherapy-based radiosurgery system performed significantly better in HI (p = 0.03) for irregular targets. The estimated total treatment time for Tomotherapy-based radiosurgery ranged from 24 minutes to 35 minutes, including 15 minutes of pretreatment megavoltage computed tomography (MVCT) and image registration, whereas that for cone-based radiosurgery ranged from 15 minutes for 1 isocenter to 75 minutes for 5 isocenters. As a rule of thumb, Tomotherapy-based radiosurgery system should be the first-line treatment for irregular lesions because of better dose homogeneity and shorter treatment time. Cone-based Linac radiosurgery system should be the treatment of choice for regular targets because of the better dose conformity, rapid dose fall-off, and reasonable treatment time

  7. SU-E-T-485: Investigation of a Synthetic Diamond Detector for Tomotherapy Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Knill, C; Nalichowski, A; Halford, R [Karmanos Cancer Institute, Detroit, MI (United States); Zakjevskii, V; Zhuang, L [Wayne State University School of Medicine, Detroit, MI (United States); Snyder, M; Burmeister, J [Karmanos Cancer Institute, Detroit, MI (United States); Wayne State University School of Medicine, Detroit, MI (United States)

    2014-06-01

    Purpose: Tomotherapy treatments are characterized by rotational deliveries of flattening-filter free fields resulting in high-gradient dose distributions. Small volume, rotationally independent detectors are needed for accurate dosimetry. PTWs microDiamond detector, with its small sensitive volume (0.004mm{sup 3}), could potentially be an ideal detector for Tomotherapy. The microDiamond detector was tested against a small volume Exradin A1SL ion chamber for Tomotherapy open-field and IMRT commissioning measurements. Methods: Custom detector holders were fabricated to allow A1SL and microDiamond measurements in the Tomotherapy Cheese phantom and a square solid water phantom. The microDiamond rotational dependence within the Tomotherapy phantom was tested by incrementally rotating the detector in between static-gantry angle Tomotherapy irradiations. Longitudinal Tomotherapy profiles, for all field sizes, were measured with the microDiamond and A1SL detectors at 1.5cm depth in the square phantom, and compared to film. Detector axes were aligned parallel to table motion. Per TG-119 recommendations, both detectors were calibrated to known doses in phantoms and used to measure high-dose points in TG-119 H and N and Prostate plans. The measurements were compared to the treatment planning system and subsequently compared to published TG-119 confidence limits. Results: The microDiamond angular dependence was less than 0.5%. The average difference between the detectors and film-measured longitudinal profile 80–20% penumbras were 0.03+/-0.04mm and 1.36+/-0.22mm for the microDiamond and A1SL, respectively. The average difference between the detector and filmmeasured field sizes were 0.07+/-0.01mm and 0.09+/-0.02mm for the microDiamond and A1SL, respectively. The measured confidence limits were 0.023 and 0.015 for microDiamond and A1SL, respectively. TG-119 reported a confidence limit of 0.034. Conclusion: The microDiamond measured open-field longitudinal Tomotherapy profiles

  8. Employing Helicity Amplitudes for Resummation

    NARCIS (Netherlands)

    Moult, I.; Stewart, I.W.; Tackmann, F.J.; Waalewijn, W.J.

    2015-01-01

    Many state-of-the-art QCD calculations for multileg processes use helicity amplitudes as their fundamental ingredients. We construct a simple and easy-to-use helicity operator basis in soft-collinear effective theory (SCET), for which the hard Wilson coefficients from matching QCD onto SCET are

  9. SU-F-BRD-02: Application of ARCHERRT-- A GPU-Based Monte Carlo Dose Engine for Radiation Therapy -- to Tomotherapy and Patient-Independent IMRT

    Energy Technology Data Exchange (ETDEWEB)

    Su, L; Du, X; Liu, T; Xu, X [Rensselaer Polytechnic Institute, Troy, NY (United States); Yang, Y; Bednarz, B [University of Wisconsin - Madison, Madison, Wisconsin (United States); Sterpin, E [Universite catholique de Louvain, Brussels, Brussels (Belgium)

    2014-06-15

    Purpose: As a module of ARCHER -- Accelerated Radiation-transport Computations in Heterogeneous EnviRonments, ARCHER{sub RT} is designed for RadioTherapy (RT) dose calculation. This paper describes the application of ARCHERRT on patient-dependent TomoTherapy and patient-independent IMRT. It also conducts a 'fair' comparison of different GPUs and multicore CPU. Methods: The source input used for patient-dependent TomoTherapy is phase space file (PSF) generated from optimized plan. For patient-independent IMRT, the open filed PSF is used for different cases. The intensity modulation is simulated by fluence map. The GEANT4 code is used as benchmark. DVH and gamma index test are employed to evaluate the accuracy of ARCHER{sub RT} code. Some previous studies reported misleading speedups by comparing GPU code with serial CPU code. To perform a fairer comparison, we write multi-thread code with OpenMP to fully exploit computing potential of CPU. The hardware involved in this study are a 6-core Intel E5-2620 CPU and 6 NVIDIA M2090 GPUs, a K20 GPU and a K40 GPU. Results: Dosimetric results from ARCHER{sub RT} and GEANT4 show good agreement. The 2%/2mm gamma test pass rates for different clinical cases are 97.2% to 99.7%. A single M2090 GPU needs 50~79 seconds for the simulation to achieve a statistical error of 1% in the PTV. The K40 card is about 1.7∼1.8 times faster than M2090 card. Using 6 M2090 card, the simulation can be finished in about 10 seconds. For comparison, Intel E5-2620 needs 507∼879 seconds for the same simulation. Conclusion: We successfully applied ARCHER{sub RT} to Tomotherapy and patient-independent IMRT, and conducted a fair comparison between GPU and CPU performance. The ARCHER{sub RT} code is both accurate and efficient and may be used towards clinical applications.

  10. 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.)

  11. Flexible helical yarn swimmers.

    Science.gov (United States)

    Zakharov, A P; Leshansky, A M; Pismen, L M

    2016-09-01

    We investigate the motion of a flexible Stokesian flagellar swimmer realised as a yarn made of two intertwined elastomer fibres, one active, that can reversibly change its length in response to a local excitation causing transition to the nematic state or swelling, and the other one, a passive isotropic elastomer with identical mechanical properties. A propagating chemical wave may provide an excitation mechanism ensuring a constant length of the excited region. Generally, the swimmer moves along a helical trajectory, and the propagation and rotation velocity are very sensitive to the ratio of the excited region to the pitch of the yarn, as well as to the size of a carried load. External excitation by a moving actuating beam is less effective, unless the direction of the beam is adjusted to rotation of the swimmer.

  12. LHD helical divertor

    International Nuclear Information System (INIS)

    Ohyabu, N.; Watanabe, T.; Ji Hantao

    1993-07-01

    The Large Helical Device (LHD) now under construction is a heliotron/torsatron device with a closed divertor system. The edge LHD magnetic structure has been studied in detail. A peculiar feature of the configuration is existence of edge surface layers, a complicated three dimensional magnetic structure which does not, however, seem to hamper the expected divertor functions. Two divertor operational modes are being considered for the LHD experiment, high density, cold radiative divertor operation as a safe heat removal scheme and high temperature divertor plasma operation. In the latter operation, a divertor plasma with temperature of a few kev, generated by efficient pumping, expects to lead to significant improvement in core plasma confinement. Conceptual designs of the LHD divertor components are under way. (author)

  13. Impact of the spinal cord position uncertainty on the dose received during head and neck helical tomotherapy

    International Nuclear Information System (INIS)

    Piotrowski, Tomasz; Kazmierska, Joanna; Sokolowski, Adam; Skorska, Malgorzata; Jodda, Agata; Ryczkowski, Adam; Cholewinski, Witold; Bak, Bartosz

    2013-01-01

    The study aims to establish the optimal planning risk volume (PRV) to the spinal cord (SC) for oropharyngeal cancer patients during adaptive radiation therapy with concurrent chemotherapy. Geometrical uncertainties of the SC were evaluated. Differences between planned and delivered maximum doses to each part of the SC were established for every fraction dose and for cumulative dose. Maximum doses were evaluated as a dose received in 0.5 and 1cm3 of the analysed part of the SC defined as C1–C2, C3–C4, C5–C6 and C7–Th1 where Cn was a n-th cervical vertebra (n=1, … , 7) and Th1 was the first thoracic vertebra. Finally, relations between dose differences and geometrical uncertainties were analysed using a relative risk (RR) and the importance of the PRV dose gradient to establish an optimal PRV for the SC. Prospective study based on the 875 observations from 25 oropharyngeal cancer patients was performed. The C1-C2 part of the SC is most exposed to risk of overdosage during chemoradiation for patients with oropharyngeal cancer due to its proximity to the clinical target volume (CTV). Doses received by other parts of the SC are smaller, with the lowest dose delivered to C7–Th1. For the C1–C2, delivered dose was higher than planned dose by 11%, while for the C7–Th1, this difference was smaller than 7%. The lowest movement of individual parts of the SC were detected for the C1–C2 and the highest for the C7–Th1. The standard deviations of the mean shift ranged respectively from 0.9 to 1.4mm and from 1.3 to 2.9mm. For each part of the SC delivered dose was smaller than planned dose to the PRV (RR<1). Our study showed that for chemoradiation of oropharyngeal cancer, using daily image guidance and proper plan adaptation scheme, the current PRV margin for the SC could be reduced to 4mm.

  14. Generation of hybrid sinograms for the recovery of kV-CT images with metal artifacts for helical tomotherapy

    International Nuclear Information System (INIS)

    Jeon, Hosang; Park, Dahl; Kim, Wontaek; Ki, Yongkan; Kim, Yong Ho; Lee, Ju Hye; Kim, Dongwon; Youn, Hanbean; Nam, Jiho; Lee, Jayoung; Kim, Ho Kyung

    2015-01-01

    Purpose: The overall goal of this study is to restore kilovoltage computed tomography (kV-CT) images which are disfigured by patients’ metal prostheses. By generating a hybrid sinogram that is a combination of kV and megavoltage (MV) projection data, the authors suggest a novel metal artifact-reduction (MAR) method that retains the image quality to match that of kV-CT and simultaneously restores the information of metal prostheses lost due to photon starvation. Methods: CT projection data contain information about attenuation coefficients and the total length of the attenuation. By normalizing raw kV projections with their own total lengths of attenuation, mean attenuation projections were obtained. In the same manner, mean density projections of MV-CT were obtained by the normalization of MV projections resulting from the forward projection of density-calibrated MV-CT images with the geometric parameters of the kV-CT device. To generate the hybrid sinogram, metal-affected signals of the kV sinogram were identified and replaced by the corresponding signals of the MV sinogram following a density calibration step with kV data. Filtered backprojection was implemented to reconstruct the hybrid CT image. To validate the authors’ approach, they simulated four different scenarios for three heads and one pelvis using metallic rod inserts within a cylindrical phantom. Five inserts describing human body elements were also included in the phantom. The authors compared the image qualities among the kV, MV, and hybrid CT images by measuring the contrast-to-noise ratio (CNR), the signal-to-noise ratio (SNR), the densities of all inserts, and the spatial resolution. In addition, the MAR performance was compared among three existing MAR methods and the authors’ hybrid method. Finally, for clinical trials, the authors produced hybrid images of three patients having dental metal prostheses to compare their MAR performances with those of the kV, MV, and three existing MAR methods. Results: The authors compared the image quality and MAR performance of the hybrid method with those of other imaging modalities and the three MAR methods, respectively. The total measured mean of the CNR (SNR) values for the nonmetal inserts was determined to be 14.3 (35.3), 15.3 (37.8), and 25.5 (64.3) for the kV, MV, and hybrid images, respectively, and the spatial resolutions of the hybrid images were similar to those of the kV images. The measured densities of the metal and nonmetal inserts in the hybrid images were in good agreement with their true densities, except in cases of extremely low densities, such as air and lung. Using the hybrid method, major streak artifacts were suitably removed and no secondary artifacts were introduced in the resultant image. In clinical trials, the authors verified that kV and MV projections were successfully combined and turned into the resultant hybrid image with high image contrast, accurate metal information, and few metal artifacts. The hybrid method also outperformed the three existing MAR methods with regard to metal information restoration and secondary artifact prevention. Conclusions: The authors have shown that the hybrid method can restore the overall image quality of kV-CT disfigured by severe metal artifacts and restore the information of metal prostheses lost due to photon starvation. The hybrid images may allow for the improved delineation of structures of interest and accurate dose calculations for radiation treatment planning for patients with metal prostheses

  15. Theoretical aspects of magnetic helicity

    International Nuclear Information System (INIS)

    Hammer, J.H.

    1985-01-01

    The magnetic helicity, usually defined as K=integralA.Bdv, where A is the vector potential and B the magnetic field, measures the topological linkage of magnetic fluxes. Helicity manifests itself in the twistedness and knottedness of flux tubes. Its significance is that it is an ideal MHD invariant. While the helicity formalism has proven very useful in understanding reversed field pinch and spheromak behavior, some problems exist in applying the method consistently for complex (e.g., toroidal) conductor geometries or in situations where magnetic flux penetrates conducting walls. Recent work has attempted to generalize K to allow for all possible geometries

  16. Godbillon Vey Helicity and Magnetic Helicity in Magnetohydrodynamics

    Science.gov (United States)

    Webb, G. M.; Hu, Q.; Anco, S.; Zank, G. P.

    2017-12-01

    The Godbillon-Vey invariant arises in homology theory, and algebraic topology, where conditions for a layered family of 2D surfaces forms a 3D manifold were elucidated. The magnetic Godbillon-Vey helicity invariant in magnetohydrodynamics (MHD) is a helicity invariant that occurs for flows, in which the magnetic helicity density hm= A\\cdotB=0 where A is the magnetic vector potential and B is the magnetic induction. Our purpose is to elucidate the evolution of the magnetic Godbillon-Vey field η =A×B/|A|2 and the Godbillon-Vey helicity hgv}= η \\cdot∇ × η in general MHD flows in which the magnetic helicity hm≠q 0. It is shown that hm acts as a source term in the Godbillon-Vey helicity transport equation, in which hm is coupled to hgv via the shear tensor of the background flow. The transport equation for hgv depends on the electric field potential ψ , which is related to the gauge for A, which takes its simplest form for the advected A gauge in which ψ =A\\cdot u where u is the fluid velocity.

  17. Three-dimensional conformal radiation therapy: the tomo-therapy approach

    International Nuclear Information System (INIS)

    Linthout, N.; Verellen, D.; Coninck, P. de; Bel, A.; Storme, G.

    2000-01-01

    Conformal radiation therapy allows the possibility of delivering high doses at the tumor volume whilst limiting the dose to the surrounding tissues and diminishing the secondary effects. With the example of the conformal radiation therapy used at the AZ VU8 (3DCRT and tomo-therapy), two treatment plans of a left ethmoid carcinoma will be evaluated and discussed in detail. The treatment of ethmoid cancer is technically difficult for both radiation therapy and surgery because of the anatomic constraints and patterns of local spread. A radiation therapy is scheduled to be delivered after surgical resection of the tumor. The treatment plan for the radiation therapy was calculated on a three-dimensional (3D) treatment planning system based on virtual simulation with a beam's eye view: George Sherouse's Gratis. An effort was made to make the plan as conformal and as homogeneous as possible to deliver a dose of 66 Gy in 33 fractions at the tumor bed with a maximum dose of 56 Gy to the right optic nerve and the chiasma. To establish the clinical utility and potential advantages of tomo-therapy over 3DCRT for ethmoid carcinoma, the treatment of this patient was also planned with Peacock Plant. For both treatment plans the isodose distributions and cumulative dose volume histograms (CDVH) were computed. Superimposing the CDVHs yielded similar curves for the target and an obvious improvement for organs at risk such as the chiasma, brainstem and the left eye when applying tomo-therapy. These results have also been reflected in the tumor control probabilities (equal for both plans) and the normal tissue complication probabilities (NTCP), yielding significant reductions in NTCP for tomo-therapy. The probability of uncomplicated tumor control was 52.7% for tomo-therapy against 38.3% for 3DCRT. (authors)

  18. Helicity multiplexed broadband metasurface holograms.

    Science.gov (United States)

    Wen, Dandan; Yue, Fuyong; Li, Guixin; Zheng, Guoxing; Chan, Kinlong; Chen, Shumei; Chen, Ming; Li, King Fai; Wong, Polis Wing Han; Cheah, Kok Wai; Pun, Edwin Yue Bun; Zhang, Shuang; Chen, Xianzhong

    2015-09-10

    Metasurfaces are engineered interfaces that contain a thin layer of plasmonic or dielectric nanostructures capable of manipulating light in a desirable manner. Advances in metasurfaces have led to various practical applications ranging from lensing to holography. Metasurface holograms that can be switched by the polarization state of incident light have been demonstrated for achieving polarization multiplexed functionalities. However, practical application of these devices has been limited by their capability for achieving high efficiency and high image quality. Here we experimentally demonstrate a helicity multiplexed metasurface hologram with high efficiency and good image fidelity over a broad range of frequencies. The metasurface hologram features the combination of two sets of hologram patterns operating with opposite incident helicities. Two symmetrically distributed off-axis images are interchangeable by controlling the helicity of the input light. The demonstrated helicity multiplexed metasurface hologram with its high performance opens avenues for future applications with functionality switchable optical devices.

  19. Hippocampus sparing in whole-brain radiotherapy. A review

    International Nuclear Information System (INIS)

    Oskan, F.; Ganswindt, U.; Schwarz, S.B.; Manapov, F.; Belka, C.; Niyazi, M.

    2014-01-01

    Radiation treatment techniques for whole-brain radiation therapy (WBRT) have not changed significantly since development of the procedure. However, the recent development of novel techniques such as intensity-modulated radiation therapy (IMRT), volumetric-modulated arc therapy (VMAT) and helical tomotherapy, as well as an increasing body of evidence concerning neural stem cells (NSCs) have altered the conventional WBRT treatment paradigm. In this regard, hippocampus-sparing WBRT is a novel technique that aims to spare critical hippocampus regions without compromising tumour control. Published data on this new technique are limited to planning and feasibility studies; data on patient outcome are still lacking. However, several prospective trials to analyse the feasibility of this technique and to document clinical outcome in terms of reduced neurotoxicity are ongoing. (orig.) [de

  20. Tomotherapy PET-guided dose escalation. A dosimetric feasibility study for patients with malignant pleural mesothelioma

    Energy Technology Data Exchange (ETDEWEB)

    Maggio, Angelo; Cutaia, Claudia; Di Dia, Amalia; Bresciani, Sara; Miranti, Anna; Poli, Matteo; Stasi, Michele [Candiolo Cancer Institute - FPO, IRCCS, Medical Physics, Turin (Italy); Del Mastro, Elena; Garibaldi, Elisabetta; Gabriele, Pietro [Candiolo Cancer Institute - FPO, IRCCS, Radiotherapy Department, Turin (Italy)

    2016-02-15

    The aim of this study was to investigate whether a safe escalation of the dose to the pleural cavity and PET/CT-positive areas in patients with unresectable malignant pleural mesothelioma (MPM) is possible using helical tomotherapy (HT). We selected 12 patients with MPM. Three planning strategies were investigated. In the first strategy (standard treatment), treated comprised a prescribed median dose to the planning target volume (PTV) boost (PTV{sub 1}) of 64.5 Gy (range: 56 Gy/28 fractions to 66 Gy/30 fractions) and 51 Gy (range: 50.4 Gy/28 fractions to 54 Gy/30 fractions) to the pleura PTV (PTV{sub 2}). Thereafter, for each patient, two dose escalation plans were generated prescribing 62.5 and 70 Gy (2.5 and 2.8 Gy/fraction, respectively) to the PTV{sub 1} and 56 Gy (2.24 Gy/fraction) to the PTV{sub 2}, in 25 fractions. Dose-volume histogram (DVH) constraints and normal tissue complication probability (NTCP) calculations were used to evaluate the differences between the plans. For all plans, the 95 % PTVs received at least 95 % of the prescribed dose. For all patients, it was possible to perform the dose escalation in accordance with the Quantitative Analysis of Normal Tissue Effects in the Clinic (QUANTEC) constraints for organs at risk (OARs). The average contralateral lung dose was < 8 Gy. NTCP values for OARs did not increase significantly compared with the standard treatment (p > 0.05), except for the ipsilateral lung. For all plans, the lung volume ratio was strongly correlated with the V{sub 20}, V{sub 30}, and V{sub 40} DVHs of the lung (p < 0.0003) and with the lung mean dose (p < 0.0001). The results of this study suggest that by using HT it is possible to safely escalate the dose delivery to at least 62.5 Gy in PET-positive areas while treating the pleural cavity to 56 Gy in 25 fractions without significantly increasing the dose to the surrounding normal organs. (orig.) [German] Ziel war es, zu untersuchen, ob mit der helikalen Tomotherapie (HT) eine

  1. Employing helicity amplitudes for resummation

    International Nuclear Information System (INIS)

    Moult, Ian; Stewart, Iain W.; Tackmann, Frank J.; Waalewijn, Wouter J.; Amsterdam Univ.

    2015-08-01

    Many state-of-the-art QCD calculations for multileg processes use helicity amplitudes as their fundamental ingredients. We construct a simple and easy-to-use helicity operator basis in soft-collinear effective theory (SCET), for which the hard Wilson coefficients from matching QCD onto SCET are directly given in terms of color-ordered helicity amplitudes. Using this basis allows one to seamlessly combine fixed-order helicity amplitudes at any order they are known with a resummation of higher-order logarithmic corrections. In particular, the virtual loop amplitudes can be employed in factorization theorems to make predictions for exclusive jet cross sections without the use of numerical subtraction schemes to handle real-virtual infrared cancellations. We also discuss matching onto SCET in renormalization schemes with helicities in 4- and d-dimensions. To demonstrate that our helicity operator basis is easy to use, we provide an explicit construction of the operator basis, as well as results for the hard matching coefficients, for pp → H+0,1,2 jets, pp → W/Z/γ+0,1,2 jets, and pp → 2,3 jets. These operator bases are completely crossing symmetric, so the results can easily be applied to processes with e + e - and e - p collisions.

  2. TU-AB-BRC-10: Modeling of Radiotherapy Linac Source Terms Using ARCHER Monte Carlo Code: Performance Comparison of GPU and MIC Computing Accelerators

    International Nuclear Information System (INIS)

    Liu, T; Lin, H; Xu, X; Su, L; Shi, C; Tang, X; Bednarz, B

    2016-01-01

    Purpose: (1) To perform phase space (PS) based source modeling for Tomotherapy and Varian TrueBeam 6 MV Linacs, (2) to examine the accuracy and performance of the ARCHER Monte Carlo code on a heterogeneous computing platform with Many Integrated Core coprocessors (MIC, aka Xeon Phi) and GPUs, and (3) to explore the software micro-optimization methods. Methods: The patient-specific source of Tomotherapy and Varian TrueBeam Linacs was modeled using the PS approach. For the helical Tomotherapy case, the PS data were calculated in our previous study (Su et al. 2014 41(7) Medical Physics). For the single-view Varian TrueBeam case, we analytically derived them from the raw patient-independent PS data in IAEA’s database, partial geometry information of the jaw and MLC as well as the fluence map. The phantom was generated from DICOM images. The Monte Carlo simulation was performed by ARCHER-MIC and GPU codes, which were benchmarked against a modified parallel DPM code. Software micro-optimization was systematically conducted, and was focused on SIMD vectorization of tight for-loops and data prefetch, with the ultimate goal of increasing 512-bit register utilization and reducing memory access latency. Results: Dose calculation was performed for two clinical cases, a Tomotherapy-based prostate cancer treatment and a TrueBeam-based left breast treatment. ARCHER was verified against the DPM code. The statistical uncertainty of the dose to the PTV was less than 1%. Using double-precision, the total wall time of the multithreaded CPU code on a X5650 CPU was 339 seconds for the Tomotherapy case and 131 seconds for the TrueBeam, while on 3 5110P MICs it was reduced to 79 and 59 seconds, respectively. The single-precision GPU code on a K40 GPU took 45 seconds for the Tomotherapy dose calculation. Conclusion: We have extended ARCHER, the MIC and GPU-based Monte Carlo dose engine to Tomotherapy and Truebeam dose calculations.

  3. TU-AB-BRC-10: Modeling of Radiotherapy Linac Source Terms Using ARCHER Monte Carlo Code: Performance Comparison of GPU and MIC Computing Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Liu, T; Lin, H; Xu, X [Rensselaer Polytechnic Institute, Troy, NY (United States); Su, L [John Hopkins University, Baltimore, MD (United States); Shi, C [Saint Vincent Medical Center, Bridgeport, CT (United States); Tang, X [Memorial Sloan Kettering Cancer Center, West Harrison, NY (United States); Bednarz, B [University of Wisconsin, Madison, WI (United States)

    2016-06-15

    Purpose: (1) To perform phase space (PS) based source modeling for Tomotherapy and Varian TrueBeam 6 MV Linacs, (2) to examine the accuracy and performance of the ARCHER Monte Carlo code on a heterogeneous computing platform with Many Integrated Core coprocessors (MIC, aka Xeon Phi) and GPUs, and (3) to explore the software micro-optimization methods. Methods: The patient-specific source of Tomotherapy and Varian TrueBeam Linacs was modeled using the PS approach. For the helical Tomotherapy case, the PS data were calculated in our previous study (Su et al. 2014 41(7) Medical Physics). For the single-view Varian TrueBeam case, we analytically derived them from the raw patient-independent PS data in IAEA’s database, partial geometry information of the jaw and MLC as well as the fluence map. The phantom was generated from DICOM images. The Monte Carlo simulation was performed by ARCHER-MIC and GPU codes, which were benchmarked against a modified parallel DPM code. Software micro-optimization was systematically conducted, and was focused on SIMD vectorization of tight for-loops and data prefetch, with the ultimate goal of increasing 512-bit register utilization and reducing memory access latency. Results: Dose calculation was performed for two clinical cases, a Tomotherapy-based prostate cancer treatment and a TrueBeam-based left breast treatment. ARCHER was verified against the DPM code. The statistical uncertainty of the dose to the PTV was less than 1%. Using double-precision, the total wall time of the multithreaded CPU code on a X5650 CPU was 339 seconds for the Tomotherapy case and 131 seconds for the TrueBeam, while on 3 5110P MICs it was reduced to 79 and 59 seconds, respectively. The single-precision GPU code on a K40 GPU took 45 seconds for the Tomotherapy dose calculation. Conclusion: We have extended ARCHER, the MIC and GPU-based Monte Carlo dose engine to Tomotherapy and Truebeam dose calculations.

  4. Pulling Helices inside Bacteria: Imperfect Helices and Rings

    Science.gov (United States)

    Allard, Jun F.; Rutenberg, Andrew D.

    2009-04-01

    We study steady-state configurations of intrinsically-straight elastic filaments constrained within rod-shaped bacteria that have applied forces distributed along their length. Perfect steady-state helices result from axial or azimuthal forces applied at filament ends, however azimuthal forces are required for the small pitches observed for MreB filaments within bacteria. Helix-like configurations can result from distributed forces, including coexistence between rings and imperfect helices. Levels of expression and/or bundling of the polymeric protein could mediate this coexistence.

  5. SU-F-T-667: Development and Validation of Dose Calculation for An Open-Source KV Treatment Planning System for Small Animal Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Prajapati, S [M D Anderson Cancer Center, Houston, TX (United States); Mo, X; Bednarz, B; Lawless, M; Hammer, C; Jeraj, R; Mackie, T [University of Wisconsin- Madison, Madison, WI (United States); Flynn, R [University of Iowa Hospitals and Clinics, Iowa City, IA (United States); Westerly, D [University of Colorado Denver, Aurora, CO (United States)

    2016-06-15

    Purpose: An open-source, convolution/superposition based kV-treatment planning system(TPS) was developed for small animal radiotherapy from previously existed in-house MV-TPS. It is flexible and applicable to both step and shoot and helical tomotherapy treatment delivery. For initial commissioning process, the dose calculation from kV-TPS was compared with measurements and Monte Carlo(MC) simulations. Methods: High resolution, low energy kernels were simulated using EGSnrc user code EDKnrc, which was used as an input in kV-TPS together with MC-simulated x-ray beam spectrum. The Blue Water™ homogeneous phantom (with film inserts) and heterogeneous phantom (with film and TLD inserts) were fabricated. Phantom was placed at 100cm SSD, and was irradiated with 250 kVp beam for 10mins with 1.1cm × 1.1cm open field (at 100cm) created by newly designed binary micro-MLC assembly positioned at 90cm SSD. Gafchromic™ EBT3 film was calibrated in-phantom following AAPM TG-61 guidelines, and were used for measurement at 5 different depths in phantom. Calibrated TLD-100s were obtained from ADCL. EGS and MNCP5 simulation were used to model experimental irradiation set up calculation of dose in phantom. Results: Using the homogeneous phantom, dose difference between film and kV-TPS was calculated: mean(x)=0.9%; maximum difference(MD)=3.1%; standard deviation(σ)=1.1%. Dose difference between MCNP5 and kV-TPS was: x=1.5%; MD=4.6%; σ=1.9%. Dose difference between EGS and kV-TPS was: x=0.8%; MD=1.9%; σ=0.8%. Using the heterogeneous phantom, dose difference between film and kV-TPS was: x=2.6%; MD=3%; σ=1.1%; and dose difference between TLD and kV-TPS was: x=2.9%; MD=6.4%; σ=2.5%. Conclusion: The inhouse, open-source kV-TPS dose calculation system was comparable within 5% of measurements and MC simulations in both homogeneous and heterogeneous phantoms. The dose calculation system of the kV-TPS is validated as a part of initial commissioning process for small animal radiotherapy

  6. Dosimetric comparison of different treatment modalities for stereotactic radiotherapy.

    Science.gov (United States)

    Hsu, Shih-Ming; Lai, Yuan-Chun; Jeng, Chien-Chung; Tseng, Chia-Ying

    2017-09-16

    The modalities for performing stereotactic radiotherapy (SRT) on the brain include the cone-based linear accelerator (linac), the flattening filter-free (FFF) volumetric modulated arc therapy (VMAT) linac, and tomotherapy. In this study, the cone-based linac, FFF-VMAT linac, and tomotherapy modalities were evaluated by measuring the differences in doses delivered during brain SRT and experimentally assessing the accuracy of the output radiation doses through clinical measurements. We employed a homemade acrylic dosimetry phantom representing the head, within which a thermoluminescent dosimeter (TLD) and radiochromic EBT3 film were installed. Using the conformity/gradient index (CGI) and Paddick methods, the quality of the doses delivered by the various SRT modalities was evaluated. The quality indicators included the uniformity, conformity, and gradient indices. TLDs and EBT3 films were used to experimentally assess the accuracy of the SRT dose output. The dose homogeneity indices of all the treatment modalities were lower than 1.25. The cone-based linac had the best conformity for all tumors, regardless of the tumor location and size, followed by the FFF-VMAT linac; tomography was the worst-performing treatment modality in this regard. The cone-based linac had the best gradient, regardless of the tumor location and size, whereas the FFF-VMAT linac had a better gradient than tomotherapy for a large tumor diameter (28 mm). The TLD and EBT3 measurements of the dose at the center of tumors indicated that the average difference between the measurements and the calculated dose was generally less than 4%. When the 3% 3-mm gamma passing rate metric was used, the average passing rates of all three treatment modalities exceeded 98%. Regarding the dose, the cone-based linac had the best conformity and steepest dose gradient for tumors of different sizes and distances from the brainstem. The results of this study suggest that SRT should be performed using the cone

  7. Transport barrier in Helical system

    International Nuclear Information System (INIS)

    Ida, Katsumi

    1998-01-01

    Experiments on the transport barrier in Helical plasmas are reviewed. There are two mechanisms of transport improvement, that results in the formation of the transport barrier. One is the improvement of neoclassical transport by reducing the ripple loss with radial electric field, which exist only in helical plasma. The other is the improvement of anomalous transport due to the suppression of fluctuations associated with a radial electric field shear both in tokamak and helical plasma. The formation of the transport barrier can be triggered by the radial electric field shear associated with the transition of the radial electric field (L/H transition or ion-electron root transition) or the peaked density or the optimization of magnetic field shear. The mechanisms of transport barrier formation are also discussed. (author). 60 refs

  8. Generalized helicity and Beltrami fields

    Energy Technology Data Exchange (ETDEWEB)

    Buniy, Roman V., E-mail: roman.buniy@gmail.com [Schmid College of Science, Chapman University, Orange, CA 92866 (United States); Isaac Newton Institute, University of Cambridge, Cambridge, CB3 0EH (United Kingdom); Kephart, Thomas W., E-mail: tom.kephart@gmail.com [Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235 (United States); Isaac Newton Institute, University of Cambridge, Cambridge, CB3 0EH (United Kingdom)

    2014-05-15

    We propose covariant and non-abelian generalizations of the magnetic helicity and Beltrami equation. The gauge invariance, variational principle, conserved current, energy–momentum tensor and choice of boundary conditions elucidate the subject. In particular, we prove that any extremal of the Yang–Mills action functional 1/4 ∫{sub Ω}trF{sub μν}F{sup μν}d{sup 4}x subject to the local constraint ε{sup μναβ}trF{sub μν}F{sub αβ}=0 satisfies the covariant non-abelian Beltrami equation. -- Highlights: •We introduce the covariant non-abelian helicity and Beltrami equation. •The Yang–Mills action and instanton term constraint lead to the Beltrami equation. •Solutions of the Beltrami equation conserve helicity.

  9. Generalized helicity and Beltrami fields

    International Nuclear Information System (INIS)

    Buniy, Roman V.; Kephart, Thomas W.

    2014-01-01

    We propose covariant and non-abelian generalizations of the magnetic helicity and Beltrami equation. The gauge invariance, variational principle, conserved current, energy–momentum tensor and choice of boundary conditions elucidate the subject. In particular, we prove that any extremal of the Yang–Mills action functional 1/4 ∫ Ω trF μν F μν d 4 x subject to the local constraint ε μναβ trF μν F αβ =0 satisfies the covariant non-abelian Beltrami equation. -- Highlights: •We introduce the covariant non-abelian helicity and Beltrami equation. •The Yang–Mills action and instanton term constraint lead to the Beltrami equation. •Solutions of the Beltrami equation conserve helicity

  10. Toroidal helical quartz forming machine

    International Nuclear Information System (INIS)

    Hanks, K.W.; Cole, T.R.

    1977-01-01

    The Scyllac fusion experimental machine used 10 cm diameter smooth bore discharge tubes formed into a simple toroidal shape prior to 1974. At about that time, it was discovered that a discharge tube was required to follow the convoluted shape of the load coil. A machine was designed and built to form a fused quartz tube with a toroidal shape. The machine will accommodate quartz tubes from 5 cm to 20 cm diameter forming it into a 4 m toroidal radius with a 1 to 5 cm helical displacement. The machine will also generate a helical shape on a linear tube. Two sets of tubes with different helical radii and wavelengths have been successfully fabricated. The problems encountered with the design and fabrication of this machine are discussed

  11. MO-D-213-04: The Proximity to the Skin of PTV Affects PTV Coverage and Skin Dose for TomoTherapy

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, T; Higgins, P; Watanabe, Y [University of Minnesota, Minneapolis, MN (United States)

    2015-06-15

    Purpose: The proximity to the skin surface of the PTV for the patients with skin disease could be a concern in terms of the PTV coverage and actual surface dose (SD). IMRT optimization algorithms increase the beam intensity close to the skin in order to compensate for lack of scattering material, leading to enhanced SD but potential hot spots. This study aims to investigate the effect of PTV proximity to the skin on planning and measured SD Methods: All measurements were done for 6 MV X-ray beam of Helical TomoTherapy. An anthropomorphic phantom was scanned in a CT simulator in a routine manner with thermoplastic mask immobilization. PTVs were created with varying distances to the skin of 0 mm -(PTV1), 1 mm- (PTV2), 2 mm-(PTV3) and 3 mm-(PTV4). Also, a 5 mm bolus was used with PTV1 (PTV5). All planning constraints were kept the same in all studies (hard constraint: 95% of the prescription dose covered 95% of the PTV). Gafchromic film (EBT3) was placed under the mask on the phantom surface, and the resulting dose was estimated using RIT software. Results: Optimizing the dose using different PTVs lead to average planned target doses of 10.8, 10.3, 10.2, 10.3 and 10.0 Gy, with maximum doses 12.2, 11.2, 11.1, 11.1 and 10.0 Gy for PTV1, PTV2, PTV3, PTV4 and PTV5, respectively. EBT3 measurements indicated a significant decrease of SD with skin distance by 12.7% (PTV1), 21.9% (PTV2), 24.8% (PTV3) and 28.4% (PTV4) comparing to prescription dose. Placement of a 5 mm bolus on the phantom surface resulted in a SD close to prescribed (+0.5%). Conclusion: This work provides a clear demonstration of the relationship between the skin dose and the PTV to the skin distance. The results indicate the necessity of a bolus even for TomoTherapy when high skin dose is required.

  12. MO-D-213-04: The Proximity to the Skin of PTV Affects PTV Coverage and Skin Dose for TomoTherapy

    International Nuclear Information System (INIS)

    Reynolds, T; Higgins, P; Watanabe, Y

    2015-01-01

    Purpose: The proximity to the skin surface of the PTV for the patients with skin disease could be a concern in terms of the PTV coverage and actual surface dose (SD). IMRT optimization algorithms increase the beam intensity close to the skin in order to compensate for lack of scattering material, leading to enhanced SD but potential hot spots. This study aims to investigate the effect of PTV proximity to the skin on planning and measured SD Methods: All measurements were done for 6 MV X-ray beam of Helical TomoTherapy. An anthropomorphic phantom was scanned in a CT simulator in a routine manner with thermoplastic mask immobilization. PTVs were created with varying distances to the skin of 0 mm -(PTV1), 1 mm- (PTV2), 2 mm-(PTV3) and 3 mm-(PTV4). Also, a 5 mm bolus was used with PTV1 (PTV5). All planning constraints were kept the same in all studies (hard constraint: 95% of the prescription dose covered 95% of the PTV). Gafchromic film (EBT3) was placed under the mask on the phantom surface, and the resulting dose was estimated using RIT software. Results: Optimizing the dose using different PTVs lead to average planned target doses of 10.8, 10.3, 10.2, 10.3 and 10.0 Gy, with maximum doses 12.2, 11.2, 11.1, 11.1 and 10.0 Gy for PTV1, PTV2, PTV3, PTV4 and PTV5, respectively. EBT3 measurements indicated a significant decrease of SD with skin distance by 12.7% (PTV1), 21.9% (PTV2), 24.8% (PTV3) and 28.4% (PTV4) comparing to prescription dose. Placement of a 5 mm bolus on the phantom surface resulted in a SD close to prescribed (+0.5%). Conclusion: This work provides a clear demonstration of the relationship between the skin dose and the PTV to the skin distance. The results indicate the necessity of a bolus even for TomoTherapy when high skin dose is required

  13. SU-F-T-468: Efficient Scanning Data Analysis for TomoTherapy

    Energy Technology Data Exchange (ETDEWEB)

    Sintay, B; Pearman, K; Maurer, J; Liu, H; Hayes, T; Wiant, D [Cone Health Cancer Center, Greensboro, NC (United States)

    2016-06-15

    Purpose: The standard TomoTherapy 2D scanning system requires manual analysis using spreadsheets or similar software. Manual analysis is time consuming and does not allow efficient use of the medical physicist or timely results that may indicate issues during the acquisition of data. The purpose of this study is to determine if an in-house solution can provide timely analysis of TomoTherapy scan data. Methods: A custom MATLAB program utilizing a streamlined graphical interface was developed to interpret the native scanning data acquired by the TomoTherapy Electrometer Measurement System (TEMS). The gold beam data provided by the manufacturer was used as a baseline for the acquired data. Two separate sets of scan data were used including longitudinal, transverse, and percent depth dose (PDD). The scan data were compared visually in an overlay and analytically for each beam width using the full width half max (FWHM) for longitudinal profiles and difference inside the field core for the transverse profiles as recommended by TG-148. A plot of the PDD percent error at each point along the curve was generated to show agreement. The time to analysis was measured on a laptop running an Intel i5 processor with 8GB of RAM. Results: The software program required on average less than 5 seconds to load and analyze the results. No conversion or reformatting of the data was required. This allowed real-time visualization of the comparison to the gold beam data as well as the parameters recommended by TG-148. The average percent difference was 0.3% for the longitudinal profiles and 0.1% for the transverse profiles. All PDD data was less than 1% different beyond dmax. Conclusion: We have developed a tool to analyze TomoTherapy scan data in real-time. This allows an efficient method to perform beam commissioning, annual QA, and adjust the beam parameters if necessary.

  14. SU-D-201-03: During-Treatment Delivery Monitoring System for TomoTherapy

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Q; Read, P [University of Virginia, Charlottesville, VA (United States)

    2016-06-15

    Purpose: Multiple error pathways can lead to delivery errors during the treatment course that cannot be caught with pre-treatment QA. While in vivo solutions are being developed for linacs, no such solution exists for tomotherapy. The purpose of this study is to develop a near real-time system for tomotherapy that can monitor the delivery and dose accumulation process during the treatment-delivery, which enable the user to assess the impact of delivery variations and/or errors and to interrupt the treatment if necessary. Methods: A program running on a tomotherapy planning station fetches the raw DAS data during treatment. Exit detector data is extracted as well as output, gantry angle, and other machine parameters. For each sample, the MLC open-close state is determined. The delivered plan is compared with the original plan via a Monte Carlo dose engine which transports fluence deviations from a pre-treatment Monte Carlo run. A report containing the difference in fluence, dose and DVH statistics is created in html format. This process is repeated until the treatment is completed. Results: Since we only need to compute the dose for the difference in fluence for a few projections each time, dose with 2% statistical uncertainty can be computed in less than 1 second on a 4-core cpu. However, the current bottleneck in this near real-time system is the repeated fetching and processing the growing DAS data file throughout the delivery. The frame rate drops from 10Hz at the beginning of treatment to 5Hz after 3 minutes and to 2Hz after 10 minutes. Conclusion: A during-treatment delivery monitor system has been built to monitor tomotherapy treatments. The system improves patient safety by allowing operators to assess the delivery variations and errors during treatment delivery and adopt appropriate actions.

  15. SU-D-201-03: During-Treatment Delivery Monitoring System for TomoTherapy

    International Nuclear Information System (INIS)

    Chen, Q; Read, P

    2016-01-01

    Purpose: Multiple error pathways can lead to delivery errors during the treatment course that cannot be caught with pre-treatment QA. While in vivo solutions are being developed for linacs, no such solution exists for tomotherapy. The purpose of this study is to develop a near real-time system for tomotherapy that can monitor the delivery and dose accumulation process during the treatment-delivery, which enable the user to assess the impact of delivery variations and/or errors and to interrupt the treatment if necessary. Methods: A program running on a tomotherapy planning station fetches the raw DAS data during treatment. Exit detector data is extracted as well as output, gantry angle, and other machine parameters. For each sample, the MLC open-close state is determined. The delivered plan is compared with the original plan via a Monte Carlo dose engine which transports fluence deviations from a pre-treatment Monte Carlo run. A report containing the difference in fluence, dose and DVH statistics is created in html format. This process is repeated until the treatment is completed. Results: Since we only need to compute the dose for the difference in fluence for a few projections each time, dose with 2% statistical uncertainty can be computed in less than 1 second on a 4-core cpu. However, the current bottleneck in this near real-time system is the repeated fetching and processing the growing DAS data file throughout the delivery. The frame rate drops from 10Hz at the beginning of treatment to 5Hz after 3 minutes and to 2Hz after 10 minutes. Conclusion: A during-treatment delivery monitor system has been built to monitor tomotherapy treatments. The system improves patient safety by allowing operators to assess the delivery variations and errors during treatment delivery and adopt appropriate actions.

  16. Helical axis stellarator equilibrium model

    International Nuclear Information System (INIS)

    Koniges, A.E.; Johnson, J.L.

    1985-02-01

    An asymptotic model is developed to study MHD equilibria in toroidal systems with a helical magnetic axis. Using a characteristic coordinate system based on the vacuum field lines, the equilibrium problem is reduced to a two-dimensional generalized partial differential equation of the Grad-Shafranov type. A stellarator-expansion free-boundary equilibrium code is modified to solve the helical-axis equations. The expansion model is used to predict the equilibrium properties of Asperators NP-3 and NP-4. Numerically determined flux surfaces, magnetic well, transform, and shear are presented. The equilibria show a toroidal Shafranov shift

  17. Resonant helical fields in tokamaks

    International Nuclear Information System (INIS)

    Okano, V.

    1990-01-01

    Poincare maps of magnetic field lines of a toroidal helical system were made. The magnetic field is a linear superposition of the magnetic fields produced by a toroidal plasma in equilibrium and by external helical currents. Analytical expression for the Poincare maps was no obtained since the magnetic field do not have symmetry. In order to obtain the maps, the equation minus derivative of l vector times B vector = 0 was numerically integrated. In the Poincare maps, the principal and the secondary magnetic island were observed. (author)

  18. Helical system. History and current state of helical research

    International Nuclear Information System (INIS)

    Yokoyama, Masayuki

    2017-01-01

    This paper described the following: (1) history of nuclear fusion research of Japan's original heliotron method, (2) worldwide development of nuclear fusion research based on helical system such as stellarator, and (3) worldwide meaning of large helical device (LHD) aiming to demonstrate the steady-state performance of heliotron type in the parameter area extrapolable to the core plasma, and research results of LHD. LHD demonstrated that the helical system is excellent in steady operation performance at the world's most advanced level. In an experiment using deuterium gas in 2017, LHD achieved to reach 120 million degrees of ion temperature, which is one index of nuclear fusion condition, demonstrated the realization of high-performance plasma capable of extrapolating to future nuclear fusion reactors, and established the foundation for full-scale research toward the realization of nuclear fusion reactor. Besides experimental research, this paper also described the helical-type stationary nuclear fusion prototype reactor, FFHR-d1, which was based on progress of large-scale simulation at the world's most advanced level. A large-scale superconducting stellarator experimental device, W7-X, with the same scale as LHD, started experiment in December 2015, whose current state is also touched on here. (A.O.)

  19. Helicity and evanescent waves. [Energy transport velocity, helicity, Lorentz transformation

    Energy Technology Data Exchange (ETDEWEB)

    Agudin, J L; Platzeck, A M [La Plata Univ. Nacional (Argentina); Albano, J R [Instituto de Astronomia y Fisica del Espacio, Buenos Aires, Argentina

    1978-02-20

    It is shown that the projection of the angular momentum of a circularly polarized electromagnetic evanescent wave along the mean velocity of energy transport (=helicity) can be reverted by a Lorentz transformation, in spite of the fact that this velocity is c.

  20. Skin dose measurements using MOSFET and TLD for head and neck patients treated with tomotherapy

    International Nuclear Information System (INIS)

    Kinhikar, Rajesh A.; Murthy, Vedang; Goel, Vineeta; Tambe, Chandrashekar M.; Dhote, Dipak S.; Deshpande, Deepak D.

    2009-01-01

    The purpose of this work was to estimate skin dose for the patients treated with tomotherapy using metal oxide semiconductor field-effect transistors (MOSFETs) and thermoluminescent dosimeters (TLDs). In vivo measurements were performed for two head and neck patients treated with tomotherapy and compared to TLD measurements. The measurements were subsequently carried out for five days to estimate the inter-fraction deviations in MOSFET measurements. The variation between skin dose measured with MOSFET and TLD for first patient was 2.2%. Similarly, the variation of 2.3% was observed between skin dose measured with MOSFET and TLD for second patient. The tomotherapy treatment planning system overestimated the skin dose as much as by 10-12% when compared to both MOSFET and TLD. However, the MOSFET measured patient skin doses also had good reproducibility, with inter-fraction deviations ranging from 1% to 1.4%. MOSFETs may be used as a viable dosimeter for measuring skin dose in areas where the treatment planning system may not be accurate.

  1. Skin dose measurements using MOSFET and TLD for head and neck patients treated with tomotherapy.

    Science.gov (United States)

    Kinhikar, Rajesh A; Murthy, Vedang; Goel, Vineeta; Tambe, Chandrashekar M; Dhote, Dipak S; Deshpande, Deepak D

    2009-09-01

    The purpose of this work was to estimate skin dose for the patients treated with tomotherapy using metal oxide semiconductor field-effect transistors (MOSFETs) and thermoluminescent dosimeters (TLDs). In vivo measurements were performed for two head and neck patients treated with tomotherapy and compared to TLD measurements. The measurements were subsequently carried out for five days to estimate the inter-fraction deviations in MOSFET measurements. The variation between skin dose measured with MOSFET and TLD for first patient was 2.2%. Similarly, the variation of 2.3% was observed between skin dose measured with MOSFET and TLD for second patient. The tomotherapy treatment planning system overestimated the skin dose as much as by 10-12% when compared to both MOSFET and TLD. However, the MOSFET measured patient skin doses also had good reproducibility, with inter-fraction deviations ranging from 1% to 1.4%. MOSFETs may be used as a viable dosimeter for measuring skin dose in areas where the treatment planning system may not be accurate.

  2. 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.

  3. Peripheral dose measurements with diode and thermoluminescence dosimeters for intensity modulated radiotherapy delivered with conventional and un-conventional linear accelerator

    International Nuclear Information System (INIS)

    Kinhikar, Rajesh; Tambe, Chandrashekhar; Kadam, Sudarshan; Deshpande, Deepak; Gamre, Poonam; Biju, George; Suryaprakash; Magai, C.S.; Shrivastava, Shyam; Dhote, Dipak

    2013-01-01

    The objective of this paper was to measure the peripheral dose (PD) with diode and thermoluminescence dosimeter (TLD) for intensity modulated radiotherapy (IMRT) with linear accelerator (conventional LINAC), and tomotherapy (novel LINAC). Ten patients each were selected from Trilogy dual-energy and from Hi-Art II tomotherapy. Two diodes were kept at 20 and 25 cm from treatment field edge. TLDs (LiF:MgTi) were also kept at same distance. TLDs were also kept at 5, 10, and 15 cm from field edge. The TLDs were read with REXON reader. The readings at the respective distance were recorded for both diode and TLD. The PD was estimated by taking the ratio of measured dose at the particular distance to the prescription dose. PD was then compared with diode and TLD for LINAC and tomotherapy. Mean PD for LINAC with TLD and diode was 2.52 cGy (SD 0.69), 2.07 cGy (SD 0.88) at 20 cm, respectively, while at 25 cm, it was 1.94 cGy (SD 0.58) and 1.5 cGy (SD 0.75), respectively. Mean PD for tomotherapy with TLD and diode was 1.681 cGy (SD 0.53) and 1.58 (SD 0.44) at 20 cm, respectively. The PD was 1.24 cGy (SD 0.42) and 1.088 cGy (SD 0.35) at 25 cm, respectively, for tomotherapy. Overall, PD from tomotherapy was found lower than LINAC by the factor of 1.2-1.5 PD measurement is essential to find out the potential of secondary cancer. PD for both (conventional LINAC) and novel LINACs (tomotherapy) were measured and compared with each other. The comparison of the values for PD presented in this work and those published in the literature is difficult because of the different experimental conditions. The diode and TLD readings were reproducible and both the detector readings were comparable. (author)

  4. Parameterization and measurements of helical magnetic fields

    International Nuclear Information System (INIS)

    Fischer, W.; Okamura, M.

    1997-01-01

    Magnetic fields with helical symmetry can be parameterized using multipole coefficients (a n , b n ). We present a parameterization that gives the familiar multipole coefficients (a n , b n ) for straight magnets when the helical wavelength tends to infinity. To measure helical fields all methods used for straight magnets can be employed. We show how to convert the results of those measurements to obtain the desired helical multipole coefficients (a n , b n )

  5. Applications of 2D helical vortex dynamics

    DEFF Research Database (Denmark)

    Okulov, Valery; Sørensen, Jens Nørkær

    2010-01-01

    In the paper, we show how the assumption of helical symmetry in the context of 2D helical vortices can be exploited to analyse and to model various cases of rotating flows. From theory, examples of three basic applications of 2D dynamics of helical vortices embedded in flows with helical symmetry...... of the vorticity field are addressed. These included some of the problems related to vortex breakdown, instability of far wakes behind rotors and vortex theory of ideal rotors....

  6. 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

  7. ICRF heating on helical devices

    International Nuclear Information System (INIS)

    Rasmussen, D.A.; Lyon, J.F.; Hoffman, D.J.; Murakami, M.; England, A.C.; Wilgen, J.B.; Jaeger, E.F.; Wang, C.; Batchelor, D.B.

    1995-01-01

    Ion cyclotron range of frequency (ICRF) heating is currently in use on CHS and W7-AS and is a major element of the heating planned for steady state helical devices. In helical devices, the lack of a toroidal current eliminates both disruptions and the need for ICRF current drive, simplifying the design of antenna structures as compared to tokamak applications. However the survivability of plasma facing components and steady state cooling issues are directly applicable to tokamak devices. Results from LHD steady state experiments should be available on a time scale to strongly influence the next generation of steady state tokamak experiments. The helical plasma geometry provides challenges not faced with tokamak ICRF heating, including the potential for enhanced fast ion losses, impurity accumulation, limited access for antenna structures, and open magnetic field lines in the plasma edge. The present results and near term plans provide the basis for steady state ICRF heating of larger helical devices. An approach which includes direct electron, mode conversion, ion minority and ion Bernstein wave heating addresses these issues

  8. ICRF heating on helical devices

    International Nuclear Information System (INIS)

    Rasmussen, D.A.; Lyon, J.F.; Hoffman, D.J.

    1995-01-01

    Ion cyclotron range of frequency (ICRF) heating is currently in use on CHS and W7AS and is a major element of the heating planned for steady state helical devices. In helical devices, the lack of a toroidal current eliminates both disruptions and the need for ICRF current drive, simplifying the design of antenna structures as compared to tokamak applications. However the survivability of plasma facing components and steady state cooling issues are directly applicable to tokamak devices. Results from LHD steady state experiments should be available on a time scale to strongly influence the next generation of steady state tokamak experiments. The helical plasma geometry provides challenges not faced with tokamak ICRF heating, including the potential for enhanced fast ion losses, impurity accumulation, limited access for antenna structures, and open magnetic field lines in the plasma edge. The present results and near term plans provide the basis for steady state ICRF heating of larger helical devices. An approach which includes direct electron, mode conversion, ion minority and ion Bernstein wave heating addresses these issues

  9. Real-time motion-adaptive-optimization (MAO) in TomoTherapy

    Energy Technology Data Exchange (ETDEWEB)

    Lu Weiguo; Chen Mingli; Ruchala, Kenneth J; Chen Quan; Olivera, Gustavo H [TomoTherapy Inc., 1240 Deming Way, Madison, WI (United States); Langen, Katja M; Kupelian, Patrick A [MD Anderson Cancer Center-Orlando, Orlando, FL (United States)], E-mail: wlu@tomotherapy.com

    2009-07-21

    IMRT delivery follows a planned leaf sequence, which is optimized before treatment delivery. However, it is hard to model real-time variations, such as respiration, in the planning procedure. In this paper, we propose a negative feedback system of IMRT delivery that incorporates real-time optimization to account for intra-fraction motion. Specifically, we developed a feasible workflow of real-time motion-adaptive-optimization (MAO) for TomoTherapy delivery. TomoTherapy delivery is characterized by thousands of projections with a fast projection rate and ultra-fast binary leaf motion. The technique of MAO-guided delivery calculates (i) the motion-encoded dose that has been delivered up to any given projection during the delivery and (ii) the future dose that will be delivered based on the estimated motion probability and future fluence map. These two pieces of information are then used to optimize the leaf open time of the upcoming projection right before its delivery. It consists of several real-time procedures, including 'motion detection and prediction', 'delivered dose accumulation', 'future dose estimation' and 'projection optimization'. Real-time MAO requires that all procedures are executed in time less than the duration of a projection. We implemented and tested this technique using a TomoTherapy (registered) research system. The MAO calculation took about 100 ms per projection. We calculated and compared MAO-guided delivery with two other types of delivery, motion-without-compensation delivery (MD) and static delivery (SD), using simulated 1D cases, real TomoTherapy plans and the motion traces from clinical lung and prostate patients. The results showed that the proposed technique effectively compensated for motion errors of all test cases. Dose distributions and DVHs of MAO-guided delivery approached those of SD, for regular and irregular respiration with a peak-to-peak amplitude of 3 cm, and for medium and large

  10. Real-time motion-adaptive-optimization (MAO) in TomoTherapy

    International Nuclear Information System (INIS)

    Lu Weiguo; Chen Mingli; Ruchala, Kenneth J; Chen Quan; Olivera, Gustavo H; Langen, Katja M; Kupelian, Patrick A

    2009-01-01

    IMRT delivery follows a planned leaf sequence, which is optimized before treatment delivery. However, it is hard to model real-time variations, such as respiration, in the planning procedure. In this paper, we propose a negative feedback system of IMRT delivery that incorporates real-time optimization to account for intra-fraction motion. Specifically, we developed a feasible workflow of real-time motion-adaptive-optimization (MAO) for TomoTherapy delivery. TomoTherapy delivery is characterized by thousands of projections with a fast projection rate and ultra-fast binary leaf motion. The technique of MAO-guided delivery calculates (i) the motion-encoded dose that has been delivered up to any given projection during the delivery and (ii) the future dose that will be delivered based on the estimated motion probability and future fluence map. These two pieces of information are then used to optimize the leaf open time of the upcoming projection right before its delivery. It consists of several real-time procedures, including 'motion detection and prediction', 'delivered dose accumulation', 'future dose estimation' and 'projection optimization'. Real-time MAO requires that all procedures are executed in time less than the duration of a projection. We implemented and tested this technique using a TomoTherapy (registered) research system. The MAO calculation took about 100 ms per projection. We calculated and compared MAO-guided delivery with two other types of delivery, motion-without-compensation delivery (MD) and static delivery (SD), using simulated 1D cases, real TomoTherapy plans and the motion traces from clinical lung and prostate patients. The results showed that the proposed technique effectively compensated for motion errors of all test cases. Dose distributions and DVHs of MAO-guided delivery approached those of SD, for regular and irregular respiration with a peak-to-peak amplitude of 3 cm, and for medium and large prostate motions. The results conceptually

  11. Rotational IMRT techniques compared to fixed gantry IMRT and Tomotherapy: multi-institutional planning study for head-and-neck cases

    Directory of Open Access Journals (Sweden)

    Lutters Gerd

    2011-02-01

    Full Text Available Abstract Background Recent developments enable to deliver rotational IMRT with standard C-arm gantry based linear accelerators. This upcoming treatment technique was benchmarked in a multi-center treatment planning study against static gantry IMRT and rotational IMRT based on a ring gantry for a complex parotid gland sparing head-and-neck technique. Methods Treatment plans were created for 10 patients with head-and-neck tumours (oropharynx, hypopharynx, larynx using the following treatment planning systems (TPS for rotational IMRT: Monaco (ELEKTA VMAT solution, Eclipse (Varian RapidArc solution and HiArt for the helical tomotherapy (Tomotherapy. Planning of static gantry IMRT was performed with KonRad, Pinnacle and Panther DAO based on step&shoot IMRT delivery and Eclipse for sliding window IMRT. The prescribed doses for the high dose PTVs were 65.1Gy or 60.9Gy and for the low dose PTVs 55.8Gy or 52.5Gy dependend on resection status. Plan evaluation was based on target coverage, conformity and homogeneity, DVHs of OARs and the volume of normal tissue receiving more than 5Gy (V5Gy. Additionally, the cumulative monitor units (MUs and treatment times of the different technologies were compared. All evaluation parameters were averaged over all 10 patients for each technique and planning modality. Results Depending on IMRT technique and TPS, the mean CI values of all patients ranged from 1.17 to 2.82; and mean HI values varied from 0.05 to 0.10. The mean values of the median doses of the spared parotid were 26.5Gy for RapidArc and 23Gy for VMAT, 14.1Gy for Tomo. For fixed gantry techniques 21Gy was achieved for step&shoot+KonRad, 17.0Gy for step&shoot+Panther DAO, 23.3Gy for step&shoot+Pinnacle and 18.6Gy for sliding window. V5Gy values were lowest for the sliding window IMRT technique (3499 ccm and largest for RapidArc (5480 ccm. The lowest mean MU value of 408 was achieved by Panther DAO, compared to 1140 for sliding window IMRT. Conclusions All

  12. Rotational IMRT techniques compared to fixed gantry IMRT and Tomotherapy: multi-institutional planning study for head-and-neck cases

    International Nuclear Information System (INIS)

    Wiezorek, Tilo; Schubert, Kai; Wagner, Daniela; Wendt, Thomas G; Brachwitz, Tim; Georg, Dietmar; Blank, Eyck; Fotina, Irina; Habl, Gregor; Kretschmer, Matthias; Lutters, Gerd; Salz, Henning

    2011-01-01

    Recent developments enable to deliver rotational IMRT with standard C-arm gantry based linear accelerators. This upcoming treatment technique was benchmarked in a multi-center treatment planning study against static gantry IMRT and rotational IMRT based on a ring gantry for a complex parotid gland sparing head-and-neck technique. Treatment plans were created for 10 patients with head-and-neck tumours (oropharynx, hypopharynx, larynx) using the following treatment planning systems (TPS) for rotational IMRT: Monaco (ELEKTA VMAT solution), Eclipse (Varian RapidArc solution) and HiArt for the helical tomotherapy (Tomotherapy). Planning of static gantry IMRT was performed with KonRad, Pinnacle and Panther DAO based on step&shoot IMRT delivery and Eclipse for sliding window IMRT. The prescribed doses for the high dose PTVs were 65.1Gy or 60.9Gy and for the low dose PTVs 55.8Gy or 52.5Gy dependend on resection status. Plan evaluation was based on target coverage, conformity and homogeneity, DVHs of OARs and the volume of normal tissue receiving more than 5Gy (V 5Gy ). Additionally, the cumulative monitor units (MUs) and treatment times of the different technologies were compared. All evaluation parameters were averaged over all 10 patients for each technique and planning modality. Depending on IMRT technique and TPS, the mean CI values of all patients ranged from 1.17 to 2.82; and mean HI values varied from 0.05 to 0.10. The mean values of the median doses of the spared parotid were 26.5Gy for RapidArc and 23Gy for VMAT, 14.1Gy for Tomo. For fixed gantry techniques 21Gy was achieved for step&shoot+KonRad, 17.0Gy for step&shoot+Panther DAO, 23.3Gy for step&shoot+Pinnacle and 18.6Gy for sliding window. V 5Gy values were lowest for the sliding window IMRT technique (3499 ccm) and largest for RapidArc (5480 ccm). The lowest mean MU value of 408 was achieved by Panther DAO, compared to 1140 for sliding window IMRT. All IMRT delivery technologies with their associated TPS

  13. A comparison of optic nerve dosimetry in craniospinal radiotherapy planned and treated with conventional and intensity modulated techniques

    International Nuclear Information System (INIS)

    Rene, Nicholas J.; Brodeur, Marylene; Parker, William; Roberge, David; Freeman, Carolyn

    2010-01-01

    Background and purpose: Some CNS tumours present leptomeningeal dissemination. Craniospinal radiotherapy is complex and recurrences may occur at sites of target volume underdosage. IMRT, being highly conformal to the target, could theoretically underdose the optic nerves if they are not specifically targeted leading to optic nerve recurrences. We analyzed optic nerve dosimetry when they are not specifically targeted. Materials and methods: We designed 3D-conformal and tomotherapy plans for our last five patients treated to the craniospinal axis, not including the optic nerves in the target volume. We analyzed the dose delivered to the optic nerves, to the anterior and posterior half of the optic nerves, and to a theoretical optic nerve-PTV. Results: The dose delivered to the optic nerves was similar for both plans in all patients (V95% close to 100%) except one in whom tomotherapy considerably underdosed the anterior optic nerves. The dose to the optic nerve-PTV was lower with tomotherapy in all patients. Conclusion: Despite not intentionally targeting the optic nerves, the dose to the optic nerves with IMRT was similar to 3D-conformal plans in most cases but left no margin for setup error. In individual cases the anterior half of the optic nerves could be significantly underdosed.

  14. Advances in conformal radiotherapy using Monte Carlo Code to design new IMRT and IORT accelerators and interpret CT numbers

    CERN Document Server

    Wysocka-Rabin, A

    2013-01-01

    The introductory chapter of this monograph, which follows this Preface, provides an overview of radiotherapy and treatment planning. The main chapters that follow describe in detail three significant aspects of radiotherapy on which the author has focused her research efforts. Chapter 2 presents studies the author worked on at the German National Cancer Institute (DKFZ) in Heidelberg. These studies applied the Monte Carlo technique to investigate the feasibility of performing Intensity Modulated Radiotherapy (IMRT) by scanning with a narrow photon beam. This approach represents an alternative to techniques that generate beam modulation by absorption, such as MLC, individually-manufactured compensators, and special tomotherapy modulators. The technical realization of this concept required investigation of the influence of various design parameters on the final small photon beam. The photon beam to be scanned should have a diameter of approximately 5 mm at Source Surface Distance (SSD) distance, and the penumbr...

  15. Generalized helicity and its time derivative

    International Nuclear Information System (INIS)

    Jarboe, T.R.; Marklin, G.J.

    1985-01-01

    Spheromaks can be sustained against resistive decay by helicity injection because they tend to obey the minimum energy principle. This principle states that a plasma-laden magnetic configuration will relax to a state of minimum energy subject to the constraint that the magnetic helicity is conserved. Use of helicity as a constraint on the minimization of energy was first proposed by Woltjer in connection with astrophysical phenomena. Helicity does decay on the resistive diffusion time. However, if helicity is created and made to flow continuoiusly into a confinement geometry, these additional linked fluxes can relax and sustain the configuration indefinitely against the resistive decay. In this paper we will present an extension of the definition of helicity to include systems where B vector can penetrate the boundary and the penetration can be varying in time. We then discuss the sustainment of RFPs and spheromaks in terms of helicity injection

  16. Feasibility of intensity-modulated and image-guided radiotherapy for locally advanced esophageal cancer

    International Nuclear Information System (INIS)

    Nguyen, Nam P; Desai, Anand; Smith-Raymond, Lexie; Jang, Siyoung; Vock, Jacqueline; Vinh-Hung, Vincent; Chi, Alexander; Vos, Paul; Pugh, Judith; Vo, Richard A; Ceizyk, Misty

    2014-01-01

    In this study the feasibility of intensity-modulated radiotherapy (IMRT) and tomotherapy-based image-guided radiotherapy (IGRT) for locally advanced esophageal cancer was assessed. A retrospective study of ten patients with locally advanced esophageal cancer who underwent concurrent chemotherapy with IMRT (1) and IGRT (9) was conducted. The gross tumor volume was treated to a median dose of 70 Gy (62.4-75 Gy). At a median follow-up of 14 months (1-39 months), three patients developed local failures, six patients developed distant metastases, and complications occurred in two patients (1 tracheoesophageal fistula, 1 esophageal stricture requiring repeated dilatations). No patients developed grade 3-4 pneumonitis or cardiac complications. IMRT and IGRT may be effective for the treatment of locally advanced esophageal cancer with acceptable complications

  17. Beam monitoring in radiotherapy and hadron-therapy

    International Nuclear Information System (INIS)

    Fontbonne, J.M.

    2012-01-01

    Radiotherapy techniques have evolved over the past twenty years. For photon beams, the development of tools such as multi leaf collimators, machines such as Cyberknife or tomo-therapy, have improved the conformation of treatments to the tumor volume and lowered maximum dose to healthy tissue. In another register, the use of proton-therapy is expanding in all countries and the development of carbon ions beams for hadron-therapy is also increasing. If techniques improve, the control requirements for the monitoring of the dose administered to patients are always the same. This document presents, first, the ins and outs of the different techniques of external beam radiotherapy: photon treatments, protons and hadrons. Starting from the basis of clinical requirements, it sets the variables to be measured in order to ensure the quality of treatment for the different considered modalities. It then describes some implementations, based on precise and rigorous specifications, for the monitoring and measurement of beams delivered by external beam radiotherapy equipments. Two instrumental techniques are particularly highlighted, plastic scintillators dosimetry for the control of megavoltage photon beams and ionization chamber dosimetry applied to proton-therapy or radiobiology experiments conducted at the GANIL facility. Analyzes and perspectives, based on the recent developments of treatment techniques, are delivered in conclusion and can serve as guide for future instrumental developments. (author)

  18. A helical scintillating fiber hodoscope

    CERN Document Server

    Altmeier, M; Bisplinghoff, J; Bissel, T; Bollmann, R; Busch, M; Büsser, K; Colberg, T; Demiroers, L; Diehl, O; Dohrmann, F; Engelhardt, H P; Eversheim, P D; Felden, O; Gebel, R; Glende, M; Greiff, J; Gross, A; Gross-Hardt, R; Hinterberger, F; Jahn, R; Jeske, M; Jonas, E; Krause, H; Lahr, U; Langkau, R; Lindemann, T; Lindlein, J; Maier, R; Maschuw, R; Mayer-Kuckuck, T; Meinerzhagen, A; Naehle, O; Pfuff, M; Prasuhn, D; Rohdjess, H; Rosendaal, D; Von Rossen, P; Sanz, B; Schirm, N; Schulz-Rojahn, M; Schwarz, V; Scobel, W; Thomas, S; Trelle, H J; Weise, E; Wellinghausen, A; Wiedmann, W; Woller, K; Ziegler, R

    1999-01-01

    A novel scintillating fiber hodoscope in helically cylindric geometry has been developed for detection of low multiplicity events of fast protons and other light charged particles in the internal target experiment EDDA at the Cooler Synchrotron COSY. The hodoscope consists of 640 scintillating fibers (2.5 mm diameter), arranged in four layers surrounding the COSY beam pipe. The fibers are helically wound in opposing directions and read out individually using 16-channel photomultipliers connected to a modified commercial encoding system. The detector covers an angular range of 9 deg. <= THETA<=72 deg. and 0 deg. <=phi (cursive,open) Greek<=360 deg. in the lab frame. The detector length is 590 mm, the inner diameter 161 mm. Geometry and granularity of the hodoscope afford a position resolution of about 1.3 mm. The detector design took into consideration a maximum of reliability and a minimum of maintenance. An LED array may be used for monitoring purposes. (author)

  19. Helical CT of ureteral disease

    International Nuclear Information System (INIS)

    Cikman, Pablo; Bengio, Ruben; Bulacio, Javier; Zirulnik, Esteban; Garimaldi, Jorge

    2000-01-01

    Among the new applications of helical CT is the study of the ureteral pathology. The objective of this paper was to evaluate patients with suspected pathology of this organ and the repercussion in the therapeutic plans. We studied 23 patients with a helical CT protocol, without IV contrast injection and performed multiplanar reconstruction (MPR). We called this procedure Pielo CT. Thirteen ureteral stones were detected, 6 calculi, 2 urinary tract tumors, dilatation of the system in a patient with neo-bladder. In 2 patients, in whom ureteral pathology was ruled out, we found other alterations that explained the symptoms, (gallbladder stones, disk protrusion). The Pielo CT let decide a therapeutical approach in 20 or 21 patients with ureteral pathology. (author)

  20. Helicity formalism and spin effects

    International Nuclear Information System (INIS)

    Anselmino, M.; Caruso, F.; Piovano, U.

    1990-01-01

    The helicity formalism and the technique to compute amplitudes for interaction processes involving leptons, quarks, photons and gluons are reviewed. Explicit calculations and examples of exploitation of symmetry properties are shown. The formalism is then applied to the discussion of several hadronic processes and spin effects: the experimental data, when related to the properties of the elementary constituent interactions, show many not understood features. Also the nucleon spin problem is briefly reviewed. (author)

  1. Helical Antimicrobial Sulfono- {gamma} -AApeptides

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yaqiong; Wu, Haifan; Teng, Peng; Bai, Ge; Lin, Xiaoyang; Zuo, Xiaobing; Cao, Chuanhai; Cai, Jianfeng

    2015-06-11

    Host-defense peptides (HDPs) such as magainin 2 have emerged as potential therapeutic agents combating antibiotic resistance. Inspired by their structures and mechanism of action, herein we report the fi rst example of antimicrobial helical sulfono- γ - AApeptide foldamers. The lead molecule displays broad-spectrum and potent antimicrobial activity against multi-drug-resistant Gram- positive and Gram-negative bacterial pathogens. Time-kill studies and fl uorescence microscopy suggest that sulfono- γ -AApeptides eradicate bacteria by taking a mode of action analogous to that of HDPs. Clear structure - function relationships exist in the studied sequences. Longer sequences, presumably adopting more-de fi ned helical structures, are more potent than shorter ones. Interestingly, the sequence with less helical propensity in solution could be more selective than the stronger helix-forming sequences. Moreover, this class of antimicrobial agents are resistant to proteolytic degradation. These results may lead to the development of a new class of antimicrobial foldamers combating emerging antibiotic-resistant pathogens.

  2. 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

  3. 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)

  4. Magnetic helicity and active filament configuration

    Science.gov (United States)

    Romano, P.; Zuccarello, F.; Poedts, S.; Soenen, A.; Zuccarello, F. P.

    2009-11-01

    Context: The role of magnetic helicity in active filament formation and destabilization is still under debate. Aims: Although active filaments usually show a sigmoid shape and a twisted configuration before and during their eruption, it is unclear which mechanism leads to these topologies. In order to provide an observational contribution to clarify these issues, we describe a filament evolution whose characteristics seem to be directly linked to the magnetic helicity transport in corona. Methods: We applied different methods to determine the helicity sign and the chirality of the filament magnetic field. We also computed the magnetic helicity transport rate at the filament footpoints. Results: All the observational signatures provided information on the positive helicity and sinistral chirality of the flux rope containing the filament material: its forward S shape, the orientation of its barbs, the bright and dark threads at 195 Å. Moreover, the magnetic helicity transport rate at the filament footpoints showed a clear accumulation of positive helicity. Conclusions: The study of this event showed a correspondence between several signatures of the sinistral chirality of the filament and several evidences of the positive magnetic helicity of the filament magnetic field. We also found that the magnetic helicity transported along the filament footpoints showed an increase just before the change of the filament shape observed in Hα images. We argued that the photospheric regions where the filament was rooted might be the preferential ways where the magnetic helicity was injected along the filament itself and where the conditions to trigger the eruption were yielded.

  5. Hippocampus sparing in whole-brain radiotherapy. A review

    Energy Technology Data Exchange (ETDEWEB)

    Oskan, F. [University of Munich, Department of Radiation Oncology and CCC Neuro-Oncology, Munich (Germany); Saarland University Medical Center, Department of Radiation Oncology, Homburg/Saar (Germany); Ganswindt, U.; Schwarz, S.B.; Manapov, F.; Belka, C.; Niyazi, M. [University of Munich, Department of Radiation Oncology and CCC Neuro-Oncology, Munich (Germany)

    2014-04-15

    Radiation treatment techniques for whole-brain radiation therapy (WBRT) have not changed significantly since development of the procedure. However, the recent development of novel techniques such as intensity-modulated radiation therapy (IMRT), volumetric-modulated arc therapy (VMAT) and helical tomotherapy, as well as an increasing body of evidence concerning neural stem cells (NSCs) have altered the conventional WBRT treatment paradigm. In this regard, hippocampus-sparing WBRT is a novel technique that aims to spare critical hippocampus regions without compromising tumour control. Published data on this new technique are limited to planning and feasibility studies; data on patient outcome are still lacking. However, several prospective trials to analyse the feasibility of this technique and to document clinical outcome in terms of reduced neurotoxicity are ongoing. (orig.) [German] Die Technik der Ganzhirnbestrahlung (''whole-brain radiation therapy'', WBRT) hat sich seit der Entwicklung nicht wesentlich veraendert. Allerdings stellten die Neuentwicklung von Techniken wie die intensitaetsmodulierte Strahlentherapie (IMRT), die volumenmodulierte Arc-Therapie (VMAT) oder die helikale Tomotherapie sowie immer groesseres Wissen ueber das neurale Stammzellkompartiment (NSCs) das herkoemmliche Ganzhirn-Paradigma in Frage. Die hippocampusschonende Ganzhirnbestrahlung ist eine neuartige Technik, welche die kritische Region des Hippocampus schont, ohne die Tumorkontrolle zu gefaehrden. Ueber diese Technik gibt es bisher nur eine begrenzte Datenlage im Sinne von Planungs- und Machbarkeitsstudien. Klinische Daten bzgl. der Behandlungsergebnisse fehlen nach wie vor, aber einige prospektive Studien sind im Gange, um nicht nur die Machbarkeit zu belegen, sondern auch das klinische Outcome im Sinne einer verringerten Neurotoxizitaet nachzuweisen. (orig.)

  6. Radiation survey of first Hi-Art II Tomotherapy vault design in India

    International Nuclear Information System (INIS)

    Kinhikar, Rajesh A.; Jamema, S.V.; Pai, Rajeshree; Sharma, P.K. Dash; Deshpande, Deepak D.

    2009-01-01

    A vault as per government-regulation compliance with adequate shielding needs was designed and constructed for Hi-Art II Tomotherapy machine being the first in India. Radiation measurements around this Tomotherapy treatment vault were carried out to check the shielding adequacy of the source housing and the vault. It was mandatory to get this un-conventional machine 'Type Approved' by Atomic Energy Regulatory Board (AERB) in India. The aim of this paper was to report on the radiation levels measured during the radiation survey carried out for this machine. The radiation levels in and around the vault were measured for stationary as well as rotational treatment procedures with the largest open field size (5 cm x 40 cm) at the isocenter with and without scattering medium. The survey was performed at three locations near each wall surrounding the vault as well. The leakage radiation from the source housing was measured both in the patient plane outside the treatment field and one meter distance from the source outside the patient plane. The radiation levels both for stationary as well as rotational procedures were within 1 mR/h. No significance difference was observed in the radiation levels measured for rotational procedures with and without scattering medium. The leakage radiation in the patient plane was found to be 0.04% (Tolerance 0.2%), while the head leakage was 0.007% (Tolerance 0.5%) of the dose rate at the isocenter. The treatment delivery with Tomotherapy does play safe radiation levels around the installation layout and also passes the leakage criteria as well.

  7. Poster - Thur Eve - 50: Planning and delivery accuracy of stereotactic radiosurgery with Tomotherapy as compared to linear-accelerator and robotic based radiosurgery.

    Science.gov (United States)

    Thakur, V; Soisson, E; Ruo, R; Doucet, R; Parker, W; Seuntjens, J

    2012-07-01

    This study includes planning and delivery comparison of three stereotactic radiosurgery techniques : Helical Tomotherapy (HT), circular collimator-based Linear-accelerator and robotic-radiosurgery. Plans were generated for two spherical targets of diameter 6 mm and 10 mm contoured at the center of a Lucite phantom, using similar planning constrains. Planning comparison showed that average conformality (0-1best) for Linear-accelerator, robotic-radiosurgery and HT was 1.43, 1.24, and 1.77 and gradient index (less is better) was 2.72, 4.50 and 13.56 respectively. For delivery comparison, plans were delivered to radiochromic film and measured dose was compared with the planned dose. For Linear-accelerator and robotic-radiosurgery more than 99% pixels-passing a gamma criteria of 3% dose difference and 1 mm distance to agreement where as for HT this value was as low as 40% for off-axis targets. Further investigation of the delivery accuracy as a function of the location of the target with in the bore was initiated using small volume A1SL (0.057 cm 3 ) and MicroLion liquid ion chamber (0.0017 cm 3 ). Point dose measurements for targets located at the center and 10 cm away from the center of the bore showed that delivered dose varied by more than 15% for targets placed away from the center of the bore as opposed to at the center. In conclusion, Linear-accelerator and the robotic-radiosurgery techniques showed preferable gradient and conformality. For HT, point dose measurements were significantly lower than predicted by the TPS when the target was positioned away from the isocenter, while they were found to be higher at isocenter. © 2012 American Association of Physicists in Medicine.

  8. Realization of fluence field modulated CT on a clinical TomoTherapy megavoltage CT system

    International Nuclear Information System (INIS)

    Szczykutowicz, Timothy P; Hermus, James; Geurts, Mark; Smilowitz, Jennifer

    2015-01-01

    The multi-leaf collimator (MLC) assembly present on TomoTherapy (Accuray, Madison WI) radiation therapy (RT) and mega voltage CT machines is well suited to perform fluence field modulated CT (FFMCT). In addition, there is a demand in the RT environment for FFMCT imaging techniques, specifically volume of interest (VOI) imaging.A clinical TomoTherapy machine was programmed to perform VOI. Four different size ROIs were placed at varying distances from isocenter. Projections intersecting the VOI received ‘full dose’ while those not intersecting the VOI received 30% of the dose (i.e. the incident fluence for non VOI projections was 30% of the incident fluence for projections intersecting the VOI). Additional scans without fluence field modulation were acquired at ‘full’ and 30% dose. The noise (pixel standard deviation) and mean CT number were measured inside the VOI region and compared between the three scans. Dose maps were generated using a dedicated TomoTherapy treatment planning dose calculator.The VOI-FFMCT technique produced an image noise 1.05, 1.00, 1.03, and 1.05 times higher than the ‘full dose’ scan for ROI sizes of 10 cm, 13 cm, 10 cm, and 6 cm respectively within the VOI region. The VOI-FFMCT technique required a total imaging dose equal to 0.61, 0.69, 0.60, and 0.50 times the ‘full dose’ acquisition dose for ROI sizes of 10 cm, 13 cm, 10 cm, and 6 cm respectively within the VOI region.Noise levels can be almost unchanged within clinically relevant VOIs sizes for RT applications while the integral imaging dose to the patient can be decreased, and/or the image quality in RT can be dramatically increased with no change in dose relative to non-FFMCT RT imaging. The ability to shift dose away from regions unimportant for clinical evaluation in order to improve image quality or reduce imaging dose has been demonstrated. This paper demonstrates that FFMCT can be performed using the MLC on a clinical TomoTherapy machine for the

  9. New formulae for magnetic relative helicity and field line helicity

    Science.gov (United States)

    Aly, Jean-Jacques

    2018-01-01

    We consider a magnetic field {B} occupying the simply connected domain D and having all its field lines tied to the boundary S of D. We assume here that {B} has a simple topology, i.e., the mapping {M} from positive to negative polarity areas of S associating to each other the two footpoints of any magnetic line, is continuous. We first present new formulae for the helicity H of {B} relative to a reference field {{B}}r having the same normal component {B}n on S, and for its field line helicity h relative to a reference vector potential {{C}}r of {{B}}r. These formulae make immediately apparent the well known invariance of these quantities under all the ideal MHD deformations that preserve the positions of the footpoints on S. They express indeed h and H either in terms of {M} and {B}n, or in terms of the values on S of a pair of Euler potentials of {B}. We next show that, for a specific choice of {{C}}r, the field line helicity h of {B} fully characterizes the magnetic mapping {M} and then the topology of the lines. Finally, we give a formula that describes the rate of change of h in a situation where the plasma moves on the perfectly conducting boundary S without changing {B}n and/or non-ideal processes, described by an unspecified term {N} in Ohm’s law, are at work in some parts of D.

  10. COMPUTED TOMOGRAPHY DOSE INDEX MEASUREMENT FOR Hi-ART MEGAVOLTAGE HELICAL CT.

    Science.gov (United States)

    Liu, Minglu; Wang, Yunlai; Liao, Xiongfei

    2016-11-01

    On-line megavoltage computed tomography (MVCT) images are used to verify patient daily set-up in Hi-ART helical TomoTherapy unit. To evaluate the patient dose from MVCT scanning in image guidance, weighted computed tomography (CT) dose index (CTDI w ) was measured with PTW TM30009 CT pencil chamber in head and body phantoms for slice thicknesses of 2, 4 and 6 mm with different scan lengths. Dose length products (DLPs) were subsequently calculated. The CTDI w and DLP were compared with XVI kV CBCT and Brilliance simulator CT for routine clinical protocols. It was shown that CTDI and DLP had close relationship with the slice thickness and the scan length. The dose distribution in the transversal plane was very inhomogeneous due to the attenuation of the couch. Patient dose from MVCT was lower than XVI CBCT for the head scan, while larger for body scan. CTDI w , which is measured easily and reproducibly, can be used to assess the patient dose in MVCT. Regular measurement should be performed in QA & QC programmes. Appropriate slice thickness and scan range should be chosen to reduce the patient dose. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. MHD stability analysis of helical system plasmas

    International Nuclear Information System (INIS)

    Nakamura, Yuji

    2000-01-01

    Several topics of the MHD stability studies in helical system plasmas are reviewed with respect to the linear and ideal modes mainly. Difference of the method of the MHD stability analysis in helical system plasmas from that in tokamak plasmas is emphasized. Lack of the cyclic (symmetric) coordinate makes an analysis more difficult. Recent topic about TAE modes in a helical system is also described briefly. (author)

  12. Employing helicity amplitudes for resummation in SCET

    International Nuclear Information System (INIS)

    Moult, Ian; Stewart, Iain W.; Tackmann, Frank J.; Waalewijn, Wouter J.; Nikhef, Amsterdam

    2016-05-01

    Helicity amplitudes are the fundamental ingredients of many QCD calculations for multi-leg processes. We describe how these can seamlessly be combined with resummation in Soft-Collinear Effective Theory (SCET), by constructing a helicity operator basis for which the Wilson coefficients are directly given in terms of color-ordered helicity amplitudes. This basis is crossing symmetric and has simple transformation properties under discrete symmetries.

  13. 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.)

  14. Tomotherapy dose distribution verification using MAGIC-f polymer gel dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Pavoni, J. F.; Pike, T. L.; Snow, J.; DeWerd, L.; Baffa, O. [Departamento de Fisica, Faculdade de Filosofia Ciencias e Letras de Ribeirao Preto-Universidade de Sao Paulo, Av. Bandeirantes, 3900 - CEP 14040-901 - Bairro Monte Alegre - Ribeirao Preto, SP (Brazil); Medical Radiation Research Center, Department of Medical Physics, University of Wisconsin, 1111 Highland Avenue, B1002 WIMR, Madison, Wisconsin 53705-2275 (United States); Departamento de Fisica, Faculdade de Filosofia Ciencias e Letras de Ribeirao Preto-Universidade de Sao Paulo, Av. Bandeirantes, 3900 - CEP 14040-901 - Bairro Monte Alegre - Ribeirao Preto, SP (Brazil)

    2012-05-15

    Purpose: This paper presents the application of MAGIC-f gel in a three-dimensional dose distribution measurement and its ability to accurately measure the dose distribution from a tomotherapy unit. Methods: A prostate intensity-modulated radiation therapy (IMRT) irradiation was simulated in the gel phantom and the treatment was delivered by a TomoTherapy equipment. Dose distribution was evaluated by the R2 distribution measured in magnetic resonance imaging. Results: A high similarity was found by overlapping of isodoses of the dose distribution measured with the gel and expected by the treatment planning system (TPS). Another analysis was done by comparing the relative absorbed dose profiles in the measured and in the expected dose distributions extracted along indicated lines of the volume and the results were also in agreement. The gamma index analysis was also applied to the data and a high pass rate was achieved (88.4% for analysis using 3%/3 mm and of 96.5% using 4%/4 mm). The real three-dimensional analysis compared the dose-volume histograms measured for the planning volumes and expected by the treatment planning, being the results also in good agreement by the overlapping of the curves. Conclusions: These results show that MAGIC-f gel is a promise for tridimensional dose distribution measurements.

  15. Tomotherapy dose distribution verification using MAGIC-f polymer gel dosimetry

    International Nuclear Information System (INIS)

    Pavoni, J. F.; Pike, T. L.; Snow, J.; DeWerd, L.; Baffa, O.

    2012-01-01

    Purpose: This paper presents the application of MAGIC-f gel in a three-dimensional dose distribution measurement and its ability to accurately measure the dose distribution from a tomotherapy unit. Methods: A prostate intensity-modulated radiation therapy (IMRT) irradiation was simulated in the gel phantom and the treatment was delivered by a TomoTherapy equipment. Dose distribution was evaluated by the R2 distribution measured in magnetic resonance imaging. Results: A high similarity was found by overlapping of isodoses of the dose distribution measured with the gel and expected by the treatment planning system (TPS). Another analysis was done by comparing the relative absorbed dose profiles in the measured and in the expected dose distributions extracted along indicated lines of the volume and the results were also in agreement. The gamma index analysis was also applied to the data and a high pass rate was achieved (88.4% for analysis using 3%/3 mm and of 96.5% using 4%/4 mm). The real three-dimensional analysis compared the dose-volume histograms measured for the planning volumes and expected by the treatment planning, being the results also in good agreement by the overlapping of the curves. Conclusions: These results show that MAGIC-f gel is a promise for tridimensional dose distribution measurements.

  16. 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)

  17. Beta-helical polymers from isocyanopeptides

    NARCIS (Netherlands)

    Cornelissen, J.J.L.M.; Donners, J.J.J.M.; Gelder, de R.; Graswinckel, W.S.; Metselaar, G.A.; Rowan, A.E.; Sommerdijk, N.A.J.M.; Nolte, R.J.M.

    2001-01-01

    Polymerization of isocyanopeptides results in the formation of high molecular mass polymers that fold in a proteinlike fashion to give helical strands in which the peptide chains are arranged in ß-sheets. The ß-helical polymers retain their structure in water and unfold in a cooperative process at

  18. Magnetic islands created by resonant helical windings

    International Nuclear Information System (INIS)

    Fernandes, A.S.; Heller, M.V.; Caldas, I.L.

    1986-01-01

    The triggering of disruptive instabilities by resonant helical windings in large aspect-ratio tokamaks is associated to destruction of magnetic surfaces. The Chirikov condition is applied to estimate analytically the helical winding current thresholds for ergodization of the magnetic field lines. (Autor) [pt

  19. Helicity amplitudes for matter-coupled gravity

    International Nuclear Information System (INIS)

    Aldrovandi, R.; Novaes, S.F.; Spehler, D.

    1992-07-01

    The Weyl-van der Waerden spinor formalism is applied to the evaluation of helicity invariant amplitudes in the framework of linearized gravitation. The graviton couplings to spin-0, 1 - 2 , 1, and 3 - 2 particles are given, and, to exhibit the reach of this method, the helicity amplitudes for the process electron + positron → photon + graviton are obtained. (author)

  20. Stiffness versus architecture of single helical polyisocyanopeptides

    NARCIS (Netherlands)

    Buul, van A.M.; Schwartz, E.; Brocorens, P.; Koepf, M.; Beljonne, D.; Maan, J.C.; Christianen, P.C.M.; Kouwer, P.H.J.; Nolte, R.J.M.; Engelkamp, H.; Blank, K.; Rowan, A.E.

    2013-01-01

    Helical structures play a vital role in nature, offering mechanical rigidity, chirality and structural definition to biological systems. Little is known about the influence of the helical architecture on the intrinsic properties of polymers. Here, we offer an insight into the nano architecture of

  1. Dynamics of zonal flows in helical systems.

    Science.gov (United States)

    Sugama, H; Watanabe, T-H

    2005-03-25

    A theory for describing collisionless long-time behavior of zonal flows in helical systems is presented and its validity is verified by gyrokinetic-Vlasov simulation. It is shown that, under the influence of particles trapped in helical ripples, the response of zonal flows to a given source becomes weaker for lower radial wave numbers and deeper helical ripples while a high-level zonal-flow response, which is not affected by helical-ripple-trapped particles, can be maintained for a longer time by reducing their bounce-averaged radial drift velocity. This implies a possibility that helical configurations optimized for reducing neoclassical ripple transport can simultaneously enhance zonal flows which lower anomalous transport.

  2. Topology of helical fluid flow

    DEFF Research Database (Denmark)

    Andersen, Morten; Brøns, Morten

    2014-01-01

    function for the topology of the streamline pattern in incompressible flows. On this basis, we perform a comprehensive study of the topology of the flow field generated by a helical vortex filament in an ideal fluid. The classical expression for the stream function obtained by Hardin (Hardin, J. C. 1982...... the zeroes of a single real function of one variable, and we show that three different flow topologies can occur, depending on a single dimensionless parameter. By including the self-induced velocity on the vortex filament by a localised induction approximation, the stream function is slightly modified...... and an extra parameter is introduced. In this setting two new flow topologies arise, but not more than two critical points occur for any combination of parameters....

  3. Helically coiled tube heat exchanger

    International Nuclear Information System (INIS)

    Harris, A.M.

    1981-01-01

    In a heat exchanger such as a steam generator for a nuclear reactor, two or more bundles of helically coiled tubes are arranged in series with the tubes in each bundle integrally continuing through the tube bundles arranged in series therewith. Pitch values for the tubing in any pair of tube bundles, taken transverse to the path of the reactor coolant flow about the tubes, are selected as a ratio of two unequal integers to permit efficient operation of each tube bundle while maintaining the various tube bundles of the heat exchanger within a compact envelope. Preferably, the helix angle and tube pitch parallel to the path of coolant flow are constant for all tubes in a single bundle so that the tubes are of approximately the same length within each bundle

  4. The quantum Hall effect helicity

    Energy Technology Data Exchange (ETDEWEB)

    Shrivastava, Keshav N., E-mail: keshav1001@yahoo.com [Department of Physics, University of Malaya, Kuala Lumpur 50603 (Malaysia); School of Physics, University of Hyderabad, Hyderabad 500046 (India)

    2015-04-16

    The quantum Hall effect in semiconductor heterostructures is explained by two signs in the angular momentum j=l±s and g=(2j+1)/(2l+1) along with the Landau factor (n+1/2). These modifications in the existing theories explain all of the fractional charges. The helicity which is the sign of the product of the linear momentum with the spin p.s plays an important role for the understanding of the data at high magnetic fields. In particular it is found that particles with positive sign in the spin move in one direction and those with negative sign move in another direction which explains the up and down stream motion of the particles.

  5. 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

  6. SU-F-P-11: Long Term Dosimetric Stability of 6 TomoTherapy Systems

    Energy Technology Data Exchange (ETDEWEB)

    Smilowitz, J; Dunkerley, D; Geurts, M; Hill, P; Yadav, P [University of Wisconsin, Madison, WI (United States)

    2016-06-15

    Purpose: The dosimetric stability of six TomoTherapy units was analyzed to investigate changes in performance over time and with system upgrades. Methods: Energy and output were tracked using monitor chamber signal, onboard MVCT detector signal and external ion chamber measurements. The systems (and monitoring periods) include 3 Hi-Art (67, 61 and 65 mos.), 2 HDA (29 and 25 mos.) and one research unit (7 mo.). Dose Control Stability system (DCS) was installed on 4 systems. Output stability is reported as deviation from reference monitor chamber signal for all systems, and from an external chamber for 4 systems. Energy stability was monitored using the relative (center versus off-axis) MVCT detector signal and/or the ratio of chamber measurements at 2 depths. The results from the clinical systems were used to benchmark the stability of the research unit, which has the same linear accelerator but runs at a higher dose rate. Results: The output based on monitor chamber data of all six systems is very stable. Non- DCS had a standard deviation of 1.7% and 1.8%. As expected, DCS systems had improved standard deviation: 0.003–0.05%. The energy was also very stable for all units. The standard deviation in exit detector flatness was 0.02–0.3%. Ion chamber output and 20/10 cm ratios supported these results. The stability for the research system, as monitored with a variety of metrics, is on par with the existing systems. Conclusion: The output and energy of six TomoTherapy units over a total of almost 10 years is quite stable. For each system, the results are consistent between the different measurement tools and techniques, proving not only the dosimetric stability, but that these quality parameters can be confirmed with various metrics. A research unit operating at a higher dose rate performed as well as the clinical treatment units. University of Wisconsin and Accuray Inc. (vendor of TomoTherapy systems) have a research agreement which supplies funds for research to

  7. Automated customized retrieval of radiotherapy data for clinical trials, audit and research.

    Science.gov (United States)

    Romanchikova, Marina; Harrison, Karl; Burnet, Neil G; Hoole, Andrew Cf; Sutcliffe, Michael Pf; Parker, Michael Andrew; Jena, Rajesh; Thomas, Simon James

    2018-02-01

    To enable fast and customizable automated collection of radiotherapy (RT) data from tomotherapy storage. Human-readable data maps (TagMaps) were created to generate DICOM-RT (Digital Imaging and Communications in Medicine standard for Radiation Therapy) data from tomotherapy archives, and provided access to "hidden" information comprising delivery sinograms, positional corrections and adaptive-RT doses. 797 data sets totalling 25,000 scans were batch-exported in 31.5 h. All archived information was restored, including the data not available via commercial software. The exported data were DICOM-compliant and compatible with major commercial tools including RayStation, Pinnacle and ProSoma. The export ran without operator interventions. The TagMap method for DICOM-RT data modelling produced software that was many times faster than the vendor's solution, required minimal operator input and delivered high volumes of vendor-identical DICOM data. The approach is applicable to many clinical and research data processing scenarios and can be adapted to recover DICOM-RT data from other proprietary storage types such as Elekta, Pinnacle or ProSoma. Advances in knowledge: A novel method to translate data from proprietary storage to DICOM-RT is presented. It provides access to the data hidden in electronic archives, offers a working solution to the issues of data migration and vendor lock-in and paves the way for large-scale imaging and radiomics studies.

  8. Unilateral and bilateral neck SIB for head and neck cancer patients. Intensity-modulated proton therapy, tomotherapy, and RapidArc

    Energy Technology Data Exchange (ETDEWEB)

    Stromberger, Carmen; Budach, Volker; Ghadjar, Pirus; Wlodarczyk, Waldemar; Marnitz, Simone [Charite - Universitaetsmedizin Berlin, Department of Radiation Oncology and Radiotherapy, Berlin (Germany); Cozzi, Luca; Fogliata, Antonella [Humanitas Cancer Center Milan, Radiotherapy and Radiosurgery Department, Milan (Italy); Jamil, Basil [Klinikum Frankfurt Oder, Praxis fuer Strahlentherapie, Frankfurt Oder (Germany); Raguse, Jan D. [Clinic for Oral and Maxillofacial Surgery, Berlin (Germany); Boettcher, Arne [Charite - Universitaetsmedizin Berlin, Department of Otorhinolaryngology, Berlin (Germany)

    2016-04-15

    To compare simultaneous integrated boost plans for intensity-modulated proton therapy (IMPT), helical tomotherapy (HT), and RapidArc therapy (RA) for patients with head and neck cancer. A total of 20 patients with squamous cell carcinoma of the head and neck received definitive chemoradiation with bilateral (n = 14) or unilateral (n = 6) neck irradiation and were planned using IMPT, HT, and RA with 54.4, 60.8, and 70.4 GyE/Gy in 32 fractions. Dose distributions, coverage, conformity, homogeneity to planning target volumes (PTV)s and sparing of organs at risk and normal tissue were compared. All unilateral and bilateral plans showed excellent PTV coverage and acceptable dose conformity. For unilateral treatment, IMPT delivered substantially lower mean doses to contralateral salivary glands (< 0.001-1.1 Gy) than both rotational techniques did (parotid gland: 6-10 Gy; submandibular gland: 15-20 Gy). Regarding the sparing of classical organs at risk for bilateral treatment, IMPT and HT were similarly excellent and RA was satisfactory. For unilateral neck irradiation, IMPT may minimize the dry mouth risk in this subgroup but showed no advantage over HT for bilateral neck treatment regarding classical organ-at-risk sparing. All methods satisfied modern standards regarding toxicity and excellent target coverage for unilateral and bilateral treatment of head and neck cancer at the planning level. (orig.) [German] Planvergleich von intensitaetsmodulierter Protonentherapie (IMPT), Tomotherapie (HT) und RapidArc-Therapie (RA) fuer Patienten mit Plattenepithelkarzinomen der Kopf-Hals-Region unter Anwendung des simultan integrierten Boost-Konzepts (SIB). Fuer 20 Patienten mit Plattenepithelkarzinomen der Kopf-Hals-Region und bilateraler (n = 14) oder unilateraler (n = 6) zervikaler primaerer Radiochemotherapie erfolgte eine IMPT-, HT- und RA-Planung mit 54,4, 60,8 und 70,4 GyE/Gy in 32 Fraktionen. Die Dosisverteilung, Abdeckung, Konformitaet und Homogenitaet der PTVs sowie die

  9. Evidence for Mixed Helicity in Erupting Filaments

    Science.gov (United States)

    Muglach, K.; Wang, Y.-M.; Kliem, B.

    2009-09-01

    Erupting filaments are sometimes observed to undergo a rotation about the vertical direction as they rise. This rotation of the filament axis is generally interpreted as a conversion of twist into writhe in a kink-unstable magnetic flux rope. Consistent with this interpretation, the rotation is usually found to be clockwise (as viewed from above) if the post-eruption arcade has right-handed helicity, but counterclockwise if it has left-handed helicity. Here, we describe two non-active-region filament events recorded with the Extreme-Ultraviolet Imaging Telescope on the Solar and Heliospheric Observatory in which the sense of rotation appears to be opposite to that expected from the helicity of the post-event arcade. Based on these observations, we suggest that the rotation of the filament axis is, in general, determined by the net helicity of the erupting system, and that the axially aligned core of the filament can have the opposite helicity sign to the surrounding field. In most cases, the surrounding field provides the main contribution to the net helicity. In the events reported here, however, the helicity associated with the filament "barbs" is opposite in sign to and dominates that of the overlying arcade.

  10. HEMISPHERIC HELICITY TREND FOR SOLAR CYCLE 24

    International Nuclear Information System (INIS)

    Hao Juan; Zhang Mei

    2011-01-01

    Using vector magnetograms obtained with the Spectro-polarimeter (SP) on board Hinode satellite, we studied two helicity parameters (local twist and current helicity) of 64 active regions that occurred in the descending phase of solar cycle 23 and the ascending phase of solar cycle 24. Our analysis gives the following results. (1) The 34 active regions of the solar cycle 24 follow the so-called hemispheric helicity rule, whereas the 30 active regions of the solar cycle 23 do not. (2) When combining all 64 active regions as one sample, they follow the hemispheric helicity sign rule as in most other observations. (3) Despite the so-far most accurate measurement of vector magnetic field given by SP/Hinode, the rule is still weak with large scatters. (4) The data show evidence of different helicity signs between strong and weak fields, confirming previous result from a large sample of ground-based observations. (5) With two example sunspots we show that the helicity parameters change sign from the inner umbra to the outer penumbra, where the sign of penumbra agrees with the sign of the active region as a whole. From these results, we speculate that both the Σ-effect (turbulent convection) and the dynamo have contributed in the generation of helicity, whereas in both cases turbulence in the convection zone has played a significant role.

  11. Verification of motion induced thread effect during tomotherapy using gel dosimetry

    International Nuclear Information System (INIS)

    Edvardsson, Anneli; Ljusberg, Anna; Ceberg, Crister; Medin, Joakim; Ambolt, Lee; Nordström, Fredrik; Ceberg, Sofie

    2015-01-01

    The purpose of the study was to evaluate how breathing motion during tomotherapy (Accuray, CA, USA) treatment affects the absorbed dose distribution. The experiments were carried out using gel dosimetry and a motion device simulating respiratory-like motion (HexaMotion, ScandiDos, Uppsala, Sweden). Normoxic polyacrylamide gels (nPAG) were irradiated, both during respiratory-like motion and in a static mode. To be able to investigate interplay effects the static absorbed dose distribution was convolved with the motion function and differences between the dynamic and convolved static absorbed dose distributions were interpreted as interplay effects. The expected dose blurring was present and the interplay effects formed a spiral pattern in the lower dose volume. This was expected since the motion induced affects the preset pitch and the theoretically predicted thread effect may emerge. In this study, the motion induced thread effect was experimentally verified for the first time

  12. Three Cases of Radiation-Induced Hepatitis B Virus Reactivation after Hepatic Tomotherapy: Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Kong, Moon Kyoo; Hong, Seong Eon; Kim, Byung Ho; Choi, Jin Hyun [Kyung Hee University College of Medicine, Seoul (Korea, Republic of)

    2011-03-15

    Radiation-induced liver disease (RILD) has been characterized as a veno-occlusive disease with anicteric elevation of alkaline phosphatase (ALP). However, some RILD patients present with elevated transaminase levels rather than with anicteric elevation of ALP, and these findings are common in the Asia-Pacific region where hepatitis B virus (HBV) infection is associated with 70-90% of hepatocelluar carcinoma (HCC) cases. In addition, the development of RILD is more common in patients with hepatitis B virus-related HCC. These findings indicate that susceptibility to RILD might be different in HBV carriers and non-carriers, and moreover, RILD in patients with HBV-related HCC might be associated with another unique pathogenesis such as HBV reactivation. However, HBV reactivation after hepatic irradiation has been reported in only a few studies. This study reports three cases of HBV reactivation after hepatic tomotherapy for management of HCC.

  13. Verification of skin dose according to the location of tumor in Tomotherapy

    International Nuclear Information System (INIS)

    Yoon, Bo Reum; Park, Su Yeon; Park, Byoung Suk; KIm, Jong Sik; Song, Ki Won

    2014-01-01

    To verify the skin dose in Tomotherapy-based radiation treatment according to the change in tumor locations, skin dose was measured by using Gafchromic EBT3 film and compared with the planned doses to find out the gap between them. In this study, to measure the skin dose, I'm RT Phantom(IBA Dosimetry, Germany) was utilized. After obtaining the 2.5 mm CT images, tumor locations and skin dose measuring points were set by using Pinnacle(ver 9.2, Philips Medical System, USA). The tumor location was decided to be 5 mm and 10 mm away from surface of the phantom and center. Considering the attenuation of a Tomo-couch, we ensured a symmetric placement between the ceiling and floor directions of the phantom. The measuring point of skin doses was set to have 3 mm and 5 mm thickness from the surface. Measurement was done 3 times. By employing TomoHD(TomoHD treatment system, Tomotherapy Inc., Madison, Wisconsin, USA), we devised Tomotherapy plans, measured 3 times by inserting Gafchromic EBT3 film into the phantom and compared the measurement with the skin dose treatment plans. The skin doses in the upper part of the phantom, when the tumor was located in the center, were found to be 7.53 cGy and 7.25 cGy in 5 mm and 3 mm respectively. If placed 5 mm away from the skin in the ceiling direction, doses were 18.06 cGy and 16.89 cGy; if 10 mm away, 20.37 cGy and 18.27 cGy, respectively. The skin doses in the lower part of the phantom, when the tumor was located in the center, recorded 8.82 cGy and 8.29 cGy in 5 mm and 3 mm, each; if located 5mm away from the lower part skin, 21.69 cGy and 19.78 cGy were respectively recorded; and if 10 mm away, 20.48 cGy and 19.57 cGy were recorded. If the tumor was placed in the center, skin doses were found to increase by 3.2-17.1% whereas if the tumor is 5 mm away from the ceiling part, the figure decreased to 2.8-9.0%. To the Tomo-couch direction, skin doses showed an average increase of 11% or over, compared to the planned treatment

  14. Three Cases of Radiation-Induced Hepatitis B Virus Reactivation after Hepatic Tomotherapy: Case Report

    International Nuclear Information System (INIS)

    Kong, Moon Kyoo; Hong, Seong Eon; Kim, Byung Ho; Choi, Jin Hyun

    2011-01-01

    Radiation-induced liver disease (RILD) has been characterized as a veno-occlusive disease with anicteric elevation of alkaline phosphatase (ALP). However, some RILD patients present with elevated transaminase levels rather than with anicteric elevation of ALP, and these findings are common in the Asia-Pacific region where hepatitis B virus (HBV) infection is associated with 70-90% of hepatocelluar carcinoma (HCC) cases. In addition, the development of RILD is more common in patients with hepatitis B virus-related HCC. These findings indicate that susceptibility to RILD might be different in HBV carriers and non-carriers, and moreover, RILD in patients with HBV-related HCC might be associated with another unique pathogenesis such as HBV reactivation. However, HBV reactivation after hepatic irradiation has been reported in only a few studies. This study reports three cases of HBV reactivation after hepatic tomotherapy for management of HCC.

  15. Polymorphic transformation of helical flagella of bacteria

    Science.gov (United States)

    Lim, Sookkyung; Howard Berg Collaboration; William Ko Collaboration; Yongsam Kim Collaboration; Wanho Lee Collaboration; Charles Peskin Collaboration

    2016-11-01

    Bacteria such as E. coli swim in an aqueous environment by utilizing the rotation of flagellar motors and alternate two modes of motility, runs and tumbles. Runs are steady forward swimming driven by bundles of flagellar filaments whose motors are turning CCW; tumbles involve a reorientation of the direction of swimming triggered by motor reversals. During tumbling, the helical flagellum undergoes polymorphic transformations, which is a local change in helical pitch, helical radius, and handedness. In this work, we investigate the underlying mechanism of structural conformation and how this polymorphic transition plays a role in bacterial swimming. National Science Foundation.

  16. Geometric validation of MV topograms for patient localization on TomoTherapy

    Science.gov (United States)

    Blanco Kiely, Janid P.; White, Benjamin M.; Low, Daniel A.; Qi, Sharon X.

    2016-01-01

    Our goal was to geometrically validate the use of mega-voltage orthogonal scout images (MV topograms) as a fast and low-dose alternative to mega-voltage computed tomography (MVCT) for daily patient localization on the TomoTherapy system. To achieve this, anthropomorphic head and pelvis phantoms were imaged on a 16-slice kilo-voltage computed tomography (kVCT) scanner to synthesize kilo-voltage digitally reconstructed topograms (kV-DRT) in the Tomotherapy detector geometry. MV topograms were generated for couch speeds of 1-4 cm s-1 in 1 cm s-1 increments with static gantry angles in the anterior-posterior and left-lateral directions. Phantoms were rigidly translated in the anterior-posterior (AP), superior-inferior (SI), and lateral (LAT) directions to simulate potential setup errors. Image quality improvement was demonstrated by estimating the noise level in the unenhanced and enhanced MV topograms using a principle component analysis-based noise level estimation algorithm. Average noise levels for the head phantom were reduced by 2.53 HU (AP) and 0.18 HU (LAT). The pelvis phantom exhibited average noise level reduction of 1.98 HU (AP) and 0.48 HU (LAT). Mattes Mutual Information rigid registration was used to register enhanced MV topograms with corresponding kV-DRT. Registration results were compared to the known rigid displacements, which assessed the MV topogram localization’s sensitivity to daily positioning errors. Reduced noise levels in the MV topograms enhanced the registration results so that registration errors were  pairs in the context bony-anatomy based procedures such as total marrow irradiation, total body irradiat