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Wolfgang A Tome - One of the best experts on this subject based on the ideXlab platform.
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normal tissue dose and second cancer risk due to megavoltage fan beam ct static Tomotherapy and helical Tomotherapy in breast radiotherapy
Radiotherapy and Oncology, 2013Co-Authors: Wolfgang A Tome, Alexandra Quinn, L Holloway, Nicholas Hardcastle, Anatoly B Rosenfeld, Peter E MetcalfeAbstract:Abstract This study investigates the dose from the 1mm collimator width megavoltage fan-beam CT (fine, normal and coarse pitch) available on Tomotherapy as well as for whole-breast Tomotherapy treatments. The BEIR VII lifetime attributable risk model was utilised to assess the significance of the imaging dose relative to the treatment dose.
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dosimetric comparison of left sided whole breast irradiation with 3dcrt forward planned imrt inverse planned imrt helical Tomotherapy and topotherapy
Radiotherapy and Oncology, 2011Co-Authors: L Schubert, E Soisson, D Westerly, Vinai Gondi, Evan Sengbusch, Bhudatt R Paliwal, Thomas R Mackie, Minesh P Mehta, Rakesh R Patel, Wolfgang A TomeAbstract:Abstract Background and purpose To compare left-sided whole breast conventional and intensity-modulated radiotherapy (IMRT) treatment planning techniques. Materials and methods Treatment plans were created for 10 consecutive patients. Three-dimensional conformal radiotherapy (3DCRT), forward-planned IMRT (for-IMRT), and inverse-planned IMRT (inv-IMRT) used two tangent beams. For-IMRT utilized up to four segments per beam. For helical Tomotherapy (HT) plans, beamlet entrance and/or exit to critical structures was blocked. Topotherapy plans, which used static gantry angles with simultaneous couch translation and inverse-planned intensity modulation, used two tangent beams. Plans were normalized to 50Gy to 95% of the retracted PTV. Results Target max doses were reduced with for-IMRT compared to 3DCRT, which were further reduced with HT, topotherapy, and inv-IMRT. HT resulted in lowest heart and ipsilateral lung max doses, but had higher mean doses. Inv-IMRT and topotherapy reduced ipsilateral lung mean and max doses compared to 3DCRT and for-IMRT. Conclusions All modalities evaluated provide adequate coverage of the intact breast. HT, topotherapy, and inv-IMRT can reduce high doses to the target and normal tissues, although HT results in increased low doses to large volume of normal tissue. For-IMRT improves target homogeneity compared with 3DCRT, but to a lesser degree than the inverse-planned modalities.
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a technique for stereotactic radiosurgery treatment planning with helical Tomotherapy
Medical Dosimetry, 2011Co-Authors: E Soisson, P W Hoban, Thomas Kammeyer, Jeffrey M Kapatoes, D Westerly, Amar Basavatia, Wolfgang A TomeAbstract:The purpose of this study was to develop an efficient and effective planning technique for stereotactic radiosurgery using helical Tomotherapy. Planning CTs and contours of 20 patients, previously treated in our clinic for brain metastases with linac-based radiosurgery using circular collimators, were used to develop a robust Tomotherapy planning technique. Plan calculation times as well as delivery times were recorded for all patients to allow for an efficiency evaluation. In addition, conformation and homogeneity indices were calculated as metrics to compare plan quality with that which is achieved with conventional radiosurgery delivery systems. A robust and efficient planning technique was identified to produce plans of radiosurgical quality using the Tomotherapy treatment planning system. Dose calculation did not exceed a few hours and resulting delivery times were less than 1 hour, which allows the process to fit into a single day radiosurgery workflow. Plan conformity compared favorably with published results for gamma knife radiosurgery. In addition, plan homogeneity was similar to linac-based approaches. The Tomotherapy planning software can be used to create plans of acceptable quality for stereotactic radiosurgery in a time that is appropriate for a radiosurgery workflow that requires that planning and delivery occur within 1 treatment day.
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SU‐FF‐T‐674: Evaluation of An Application to Transfer Tomotherapy Plans to Step‐And‐Shoot IMRT Plans
Medical Physics, 2009Co-Authors: R. Tolakanahalli, P W Hoban, R. Holmberg, C. Sundgren, P. Ploc, Wolfgang A TomeAbstract:Purpose: The goal of this study is to determine if the IMRT plans generated by SharePlan were equivalent to the original Tomotherapy treatment plans and if this could be used to generate IMRT plans for clinical sites/patients. Method and Materials: For the purpose of evaluation, a total of eight patient plans that are currently being treated with the Tomotherapy system at the University of Wisconsin, Madison were chosen. Along with some of the common sites like the prostate, lung and H&N, complex plans for which Tomotherapy system provides the best results were chosen. The three special cases were 1) whole brain (WB) with hippocampal sparing 2) nasal structure 3) multiple lesions on the scalp with brain sparing. Results: For simple cases such as prostate, lung and H&N treatment plans, SharePlan generates clinically acceptable plans that are similar to the original Tomotherapy plans. For special cases such as surface lesions and WB treatment with hippocampal avoidance, Tomotherapy provides better target coverage and organ sparing. Conclusion: SharePlan is a fast and robust tool to translate Tomotherapy plans to step‐and‐shoot IMRT plans. SharePlan generates treatment plans comparable to Tomotherapy, and the time required to generate one plan for a simple case on an intermediate grid resolution is approximately 7 minutes.
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Dosimetric verification of helical Tomotherapy for total scalp irradiation.
Medical Physics, 2008Co-Authors: Nicholas Hardcastle, E Soisson, Anatoly B Rosenfeld, Peter E Metcalfe, Wolfgang A TomeAbstract: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 achievemore » the prescription dose at the surface ({
Peter E Metcalfe - One of the best experts on this subject based on the ideXlab platform.
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normal tissue dose and second cancer risk due to megavoltage fan beam ct static Tomotherapy and helical Tomotherapy in breast radiotherapy
Radiotherapy and Oncology, 2013Co-Authors: Wolfgang A Tome, Alexandra Quinn, L Holloway, Nicholas Hardcastle, Anatoly B Rosenfeld, Peter E MetcalfeAbstract:Abstract This study investigates the dose from the 1mm collimator width megavoltage fan-beam CT (fine, normal and coarse pitch) available on Tomotherapy as well as for whole-breast Tomotherapy treatments. The BEIR VII lifetime attributable risk model was utilised to assess the significance of the imaging dose relative to the treatment dose.
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Dosimetric verification of helical Tomotherapy for total scalp irradiation.
Medical Physics, 2008Co-Authors: Nicholas Hardcastle, E Soisson, Anatoly B Rosenfeld, Peter E Metcalfe, Wolfgang A TomeAbstract: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 achievemore » the prescription dose at the surface ({
E Soisson - One of the best experts on this subject based on the ideXlab platform.
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dosimetric comparison of left sided whole breast irradiation with 3dcrt forward planned imrt inverse planned imrt helical Tomotherapy and topotherapy
Radiotherapy and Oncology, 2011Co-Authors: L Schubert, E Soisson, D Westerly, Vinai Gondi, Evan Sengbusch, Bhudatt R Paliwal, Thomas R Mackie, Minesh P Mehta, Rakesh R Patel, Wolfgang A TomeAbstract:Abstract Background and purpose To compare left-sided whole breast conventional and intensity-modulated radiotherapy (IMRT) treatment planning techniques. Materials and methods Treatment plans were created for 10 consecutive patients. Three-dimensional conformal radiotherapy (3DCRT), forward-planned IMRT (for-IMRT), and inverse-planned IMRT (inv-IMRT) used two tangent beams. For-IMRT utilized up to four segments per beam. For helical Tomotherapy (HT) plans, beamlet entrance and/or exit to critical structures was blocked. Topotherapy plans, which used static gantry angles with simultaneous couch translation and inverse-planned intensity modulation, used two tangent beams. Plans were normalized to 50Gy to 95% of the retracted PTV. Results Target max doses were reduced with for-IMRT compared to 3DCRT, which were further reduced with HT, topotherapy, and inv-IMRT. HT resulted in lowest heart and ipsilateral lung max doses, but had higher mean doses. Inv-IMRT and topotherapy reduced ipsilateral lung mean and max doses compared to 3DCRT and for-IMRT. Conclusions All modalities evaluated provide adequate coverage of the intact breast. HT, topotherapy, and inv-IMRT can reduce high doses to the target and normal tissues, although HT results in increased low doses to large volume of normal tissue. For-IMRT improves target homogeneity compared with 3DCRT, but to a lesser degree than the inverse-planned modalities.
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a technique for stereotactic radiosurgery treatment planning with helical Tomotherapy
Medical Dosimetry, 2011Co-Authors: E Soisson, P W Hoban, Thomas Kammeyer, Jeffrey M Kapatoes, D Westerly, Amar Basavatia, Wolfgang A TomeAbstract:The purpose of this study was to develop an efficient and effective planning technique for stereotactic radiosurgery using helical Tomotherapy. Planning CTs and contours of 20 patients, previously treated in our clinic for brain metastases with linac-based radiosurgery using circular collimators, were used to develop a robust Tomotherapy planning technique. Plan calculation times as well as delivery times were recorded for all patients to allow for an efficiency evaluation. In addition, conformation and homogeneity indices were calculated as metrics to compare plan quality with that which is achieved with conventional radiosurgery delivery systems. A robust and efficient planning technique was identified to produce plans of radiosurgical quality using the Tomotherapy treatment planning system. Dose calculation did not exceed a few hours and resulting delivery times were less than 1 hour, which allows the process to fit into a single day radiosurgery workflow. Plan conformity compared favorably with published results for gamma knife radiosurgery. In addition, plan homogeneity was similar to linac-based approaches. The Tomotherapy planning software can be used to create plans of acceptable quality for stereotactic radiosurgery in a time that is appropriate for a radiosurgery workflow that requires that planning and delivery occur within 1 treatment day.
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Dosimetric verification of helical Tomotherapy for total scalp irradiation.
Medical Physics, 2008Co-Authors: Nicholas Hardcastle, E Soisson, Anatoly B Rosenfeld, Peter E Metcalfe, Wolfgang A TomeAbstract: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 achievemore » the prescription dose at the surface ({
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Helical Tomotherapy quality assurance.
International Journal of Radiation Oncology Biology Physics, 2008Co-Authors: John Balog, E SoissonAbstract: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.
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comparison of linac based fractionated stereotactic radiotherapy and Tomotherapy treatment plans for skull base tumors
Radiotherapy and Oncology, 2006Co-Authors: E Soisson, Wolfgang A Tome, Gregory M Richards, Minesh P MehtaAbstract:Abstract Background and purpose To compare and evaluate helical Tomotherapy and linac based fractionated stereotactic radiotherapy (FSRT) techniques in the treatment of skull-base tumors. Patients and methods Ten patients diagnosed with skull-base tumors, originally planned for optically guided FSRT to prescribed doses of 50.4–54Gy were replanned for treatment with clinically deliverable helical Tomotherapy. All original CT scans, MR-CT fusion defined target and normal structure contours, and PTV margins were used for helical Tomotherapy planning. Linac based plans utilized one of the following FSRT planning techniques: non-coplanar or coplanar intensity modulated radiation therapy (IMRT), multiple non-coplanar conformal arcs, and non-coplanar conformal radiation therapy (CRT). These plans were used as the standard to which the subsequent Tomotherapy plans were compared, using the following criteria: prescription isodose to target volume (PITV) ratios, an inhomogeneity index (II), equivalent uniform dose (EUD) for PTV volumes, mean normalized total doses (NTD mean ) for critical structures, and size of 10, 20, and 30Gy isodose volumes. Results Use of both linac based FSRT techniques and helical Tomotherapy generated highly conformal treatment plans. Tomotherapy plans, which are predominantly coplanar in nature, compared to non-coplanar linac based plans exhibited increased PITV ratios, variable change in II, similar EUD values, and generally comparable NTD mean values for organs at risk. When compared to non-coplanar field arrangements, deliverable (as opposed to idealized) Tomotherapy plans also resulted in 13–540% increases in low dose isodose volumes. All criteria except for the II, which was generally improved with Tomotherapy, were found to be similar when coplanar linac based plans were compared to helical Tomotherapy plans. Conclusions Results show a distinct advantage in using non-coplanar beam arrangements for treatment of skull-base tumors. In the case where disease spreads far inferiorly, limiting the ability to use non-coplanar arrangements, helical Tomotherapy can be used to generate a comparable treatment plan, with potentially superior homogeneity.
Minesh P Mehta - One of the best experts on this subject based on the ideXlab platform.
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dosimetric comparison of left sided whole breast irradiation with 3dcrt forward planned imrt inverse planned imrt helical Tomotherapy and topotherapy
Radiotherapy and Oncology, 2011Co-Authors: L Schubert, E Soisson, D Westerly, Vinai Gondi, Evan Sengbusch, Bhudatt R Paliwal, Thomas R Mackie, Minesh P Mehta, Rakesh R Patel, Wolfgang A TomeAbstract:Abstract Background and purpose To compare left-sided whole breast conventional and intensity-modulated radiotherapy (IMRT) treatment planning techniques. Materials and methods Treatment plans were created for 10 consecutive patients. Three-dimensional conformal radiotherapy (3DCRT), forward-planned IMRT (for-IMRT), and inverse-planned IMRT (inv-IMRT) used two tangent beams. For-IMRT utilized up to four segments per beam. For helical Tomotherapy (HT) plans, beamlet entrance and/or exit to critical structures was blocked. Topotherapy plans, which used static gantry angles with simultaneous couch translation and inverse-planned intensity modulation, used two tangent beams. Plans were normalized to 50Gy to 95% of the retracted PTV. Results Target max doses were reduced with for-IMRT compared to 3DCRT, which were further reduced with HT, topotherapy, and inv-IMRT. HT resulted in lowest heart and ipsilateral lung max doses, but had higher mean doses. Inv-IMRT and topotherapy reduced ipsilateral lung mean and max doses compared to 3DCRT and for-IMRT. Conclusions All modalities evaluated provide adequate coverage of the intact breast. HT, topotherapy, and inv-IMRT can reduce high doses to the target and normal tissues, although HT results in increased low doses to large volume of normal tissue. For-IMRT improves target homogeneity compared with 3DCRT, but to a lesser degree than the inverse-planned modalities.
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SU‐FF‐T‐443: Validation of Tomotherapy Machine Matching Procedure at the University of Wisconsin
Medical Physics, 2007Co-Authors: Hazim Jaradat, Wolfgang A Tome, Thomas R Mackie, B Paliwal, Minesh P MehtaAbstract:Purpose: To verify and validate an in‐house developed procedure used to readily transfer treatment plans between two Tomotherapy machines without the need to re‐optimize the plan. Easy patient transfer between Tomotherapy machines provides smooth patient flow in the clinic and reduces the time needed to complete patients' treatments as scheduled. It also reduces the possibility of introducing errors in the transfer of patients from one machine to another. Method and Materials: Two Tomotherapy Hi‐ART machines: Tomotherapy I, running software version 2.1.0.2 and Tomotherapy II running software version 2.2.1.2 (Tomotherapy Inc. Madison, WI.). The Tomotherapy planning was used for comparing treatment plans. The Delivery Quality Assurance (DQA) module of the Tomotherapy planning software was used to compare delivered dose to films within the Tomo phantom to the calculated dose from the plans. Results: Comprehensive tests using film and ion chamberdosimetry show that the beam model is true representation of both machines within measurement uncertainty. DQA procedures show that transferred plans are delivered accurately within IMRT acceptable limits (3% of prescribed dose and 3mm distance to agreement). Conclusion: Using this approach the two UW Tomotherapy machines were found to be similar and can deliver the same treatment plan within tolerances acceptable by IMRTtreatments. On several occasions, Tomotherapy treatment plans were transferred between the two Tomotherapy machines to avoid treatment cancellation. Tomotherapy treatment plan transfer is accomplished within a reasonable time frame (5–10 minutes per plan) without changing the final outcome of the plans. Conflict of Interest and Disclaimer: R. Mackie has financial interest in Tomotherapy Inc., and potential conflict of interest. The procedure and methods presented here are solely developed by the University of Wisconsin physics for internal use. Tomotherapy Inc. did not participate in this study and they do not support or recommend the procedure presented here.
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comparison of linac based fractionated stereotactic radiotherapy and Tomotherapy treatment plans for skull base tumors
Radiotherapy and Oncology, 2006Co-Authors: E Soisson, Wolfgang A Tome, Gregory M Richards, Minesh P MehtaAbstract:Abstract Background and purpose To compare and evaluate helical Tomotherapy and linac based fractionated stereotactic radiotherapy (FSRT) techniques in the treatment of skull-base tumors. Patients and methods Ten patients diagnosed with skull-base tumors, originally planned for optically guided FSRT to prescribed doses of 50.4–54Gy were replanned for treatment with clinically deliverable helical Tomotherapy. All original CT scans, MR-CT fusion defined target and normal structure contours, and PTV margins were used for helical Tomotherapy planning. Linac based plans utilized one of the following FSRT planning techniques: non-coplanar or coplanar intensity modulated radiation therapy (IMRT), multiple non-coplanar conformal arcs, and non-coplanar conformal radiation therapy (CRT). These plans were used as the standard to which the subsequent Tomotherapy plans were compared, using the following criteria: prescription isodose to target volume (PITV) ratios, an inhomogeneity index (II), equivalent uniform dose (EUD) for PTV volumes, mean normalized total doses (NTD mean ) for critical structures, and size of 10, 20, and 30Gy isodose volumes. Results Use of both linac based FSRT techniques and helical Tomotherapy generated highly conformal treatment plans. Tomotherapy plans, which are predominantly coplanar in nature, compared to non-coplanar linac based plans exhibited increased PITV ratios, variable change in II, similar EUD values, and generally comparable NTD mean values for organs at risk. When compared to non-coplanar field arrangements, deliverable (as opposed to idealized) Tomotherapy plans also resulted in 13–540% increases in low dose isodose volumes. All criteria except for the II, which was generally improved with Tomotherapy, were found to be similar when coplanar linac based plans were compared to helical Tomotherapy plans. Conclusions Results show a distinct advantage in using non-coplanar beam arrangements for treatment of skull-base tumors. In the case where disease spreads far inferiorly, limiting the ability to use non-coplanar arrangements, helical Tomotherapy can be used to generate a comparable treatment plan, with potentially superior homogeneity.
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SU‐FF‐T‐412: The Feasibility of Using Tomotherapy Hi‐Art Machine for Stereotactic Radiosurgery
Medical Physics, 2005Co-Authors: Hazim Jaradat, Wolfgang A Tome, Minesh P MehtaAbstract:Purpose: To study the feasibility of treating multiple‐brain metastass with stereotactic radiosurgery using the Tomotherapy Hi‐Art machine, and to compare Tomotherapy stereotactic radiosurgerytreatment plans with conventional linac‐based stereotactic radiosurgery plans. Method and Materials: Five previously treated patients with multiple brain metastases ranging from 1 to 5 metastases were selected for the study. These five patients were treated with linacstereotactic radiosurgery. The same structures and prescription doses used for linacradiosurgery were also used to produce stereotactic radiosurgerytreatment plans on the Tomotherapy planning system. In order to compare the Tomotherapy plans to the linac‐based plans, the homogeneity of the target volumes, as well as the PITV, the volume of normal braintissue receiving at least 10Gy and treatment time were considered. Results: Analysis of the five plans shows that the target dose uniformity, target dose conformality, and the treatment time for each plan is much improved for Tomotherapy. The plans show that on average using Tomotherapy planning system increases the dose uniformity by 70%, increases the target‐dose conformality by 42% while it reduces the normal tissue volume receiving at least 10 Gy by about 40% for large metastases. On the other hand, for metastases smaller than 1cc Tomotherapy increases the 10.0 Gy volume over that for a conventional linac plan by about 60%. Conclusion: These results show that Tomotherapy could be used for treating patients with multiple brain metastases using stereotactic radiosurgey.
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Helical Tomotherapy as a means of delivering accelerated partial breast irradiation.
Technology in Cancer Research & Treatment, 2004Co-Authors: Susanta K Hui, J M Kapatoes, Rupak K. Das, Gustavo Oliviera, Stuart Becker, Heath Odau, John D. Fenwick, Rakesh Patel, Robert R. Kuske, Minesh P MehtaAbstract:A novel treatment approach utilizing helical Tomotherapy for partial breast irradiation for patients with early-stage breast cancer is described. This technique may serve as an alternative to high dose-rate (HDR) interstitial brachytherapy and standard linac-based approaches. Through helical Tomotherapy, highly conformal irradiation of target volumes and avoidance of normal sensitive structures can be achieved. Unlike HDR brachytherapy, it is noninvasive. Unlike other linac-based techniques, it provides image-guided adaptive radiotherapy along with intensity modulation. A treatment planning CT scan was obtained as usual on a post-lumpectomy patient undergoing HDR interstitial breast brachytherapy. The patient underwent catheter placement for HDR treatment and was positioned prone on a specially designed position-supporting mattress during CT. The planning target volume (PTV) was defined as the lumpectomy bed plus a 20 mm margin. The prescription dose was 34 Gy (10 fx of 3.4 Gy) in both the CT based HDR and on the Tomotherapy plan. Cumulative dose-volume histograms (DVHs) were generated and analyzed for the target, lung, heart, skin, pectoralis muscle, and chest wall for both HDR brachytherapy and helical Tomotherapy. Dosimetric coverage of the target with helical Tomotherapy was conformal and homogeneous. "Hot spots" (> or =150% isodose line) were present around implanted dwell positions in brachytherapy plan whereas no isodose lines higher than 109% were present in the helical Tomotherapy plan. Similar dose coverage was achieved for lung, pectoralis muscle, heart, chest wall and breast skin with the two methods. We also compared our results to that obtained using conventional linac-based three dimensional (3D) conformal accelerated partial breast irradiation. Dose homogeneity is excellent with 3D conformal irradiation, and lung, heart and chest wall dose is less than for either HDR brachytherapy or helical Tomotherapy but skin and pectoral muscle doses were higher than with the other techniques. Our results suggest that helical Tomotherapy can serve as an effective means of delivering accelerated partial breast irradiation and may offer superior dose homogeneity compared to HDR brachytherapy.
Klaus Herfarth - One of the best experts on this subject based on the ideXlab platform.
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Helical Tomotherapy as a new treatment technique for whole abdominal irradiation.
Strahlentherapie Und Onkologie, 2008Co-Authors: N. Rochet, Florian Sterzing, Alexandra D Jensen, Julien Dinkel, Klaus Herfarth, Kai Schubert, Michael H. R. Eichbaum, Andreas Schneeweiss, Christof Sohn, Juergen DebusAbstract:To describe a new intensity-modulated radiotherapy (IMRT) technique using helical Tomotherapy for whole abdominal irradiation (WAI) in patients with advanced ovarian cancer. 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). 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. Helical Tomotherapy is feasible and fast for WAI. Tomotherapy enabled excellent coverage of the PTV and effective sparing of liver, kidneys and bone marrow.
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evaluating target coverage and normal tissue sparing in the adjuvant radiotherapy of malignant pleural mesothelioma helical Tomotherapy compared with step and shoot imrt
Radiotherapy and Oncology, 2008Co-Authors: Florian Sterzing, Kai Schubert, G Srokaperez, Marc W Munter, Christian Thieke, Peter E Huber, Jurgen Debus, Klaus HerfarthAbstract:Abstract Purpose To evaluate the potential of helical Tomotherapy in the adjuvant treatment of malignant pleural mesothelioma and compare target homogeneity, conformity and normal tissue dose with step-and-shoot intensity-modulated radiotherapy. Methods and materials Ten patients with malignant pleural mesothelioma who had undergone neoadjuvant chemotherapy with cisplatin and permetrexed followed by extrapleural pneumonectomy (EPP) were treated in our department with 54Gy to the hemithorax delivered by step-and-shoot IMRT. A planning comparison was performed by creating radiation plans for helical Tomotherapy. The different plans were compared by analysing target homogeneity using the homogeneity indices HI max and HI min and target conformity by using the conformity index CI 95 . To assess target coverage and normal tissue sparing TV 90 , TV 95 and mean and maximum doses were compared. Results Both modalities achieved excellent dose distributions while sparing organs at risk. Target coverage and homogeneity could be increased significantly with helical Tomotherapy compared with step-and-shoot IMRT. Mean dose to the contralateral lung could be lowered beyond 5Gy. Conclusions Our planning study showed that helical Tomotherapy is an excellent option for the adjuvant intensity-modulated radiotherapy of MPM. It is capable of improving target coverage and homogeneity.
