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

Abstract

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 clinicallymore » 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.« less

Authors:
;  [1];  [2]; ; ;  [3];  [4]
  1. University of Sydney, Sydney, NSW (Australia)
  2. Odense University Hospital, Odense C (Denmark)
  3. Liverpool & Macarthur Cancer Therapy Centres, Liverpool, NSW (United Kingdom)
  4. Ingham Institute, Sydney, NSW (Australia)
Publication Date:
OSTI Identifier:
22548420
Resource Type:
Journal Article
Journal Name:
Medical Physics
Additional Journal Information:
Journal Volume: 42; Journal Issue: 6; Other Information: (c) 2015 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0094-2405
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; 61 RADIATION PROTECTION AND DOSIMETRY; ACCURACY; COMPUTERIZED TOMOGRAPHY; CT-GUIDED RADIOTHERAPY; DOSIMETRY; HEALTH HAZARDS; LUNGS; NEOPLASMS; PATIENTS; PHANTOMS; RADIATION DOSE DISTRIBUTIONS; RADIATION DOSES

Citation Formats

Blake, S, Thwaites, D, Hansen, C, Deshpande, S, Phan, P, Franji, I, and Holloway, L. SU-E-T-370: Evaluating Plan Quality and Dose Delivery Accuracy of Tomotherapy SBRT Treatments for Lung Cancer. United States: N. p., 2015. Web. doi:10.1118/1.4924731.
Blake, S, Thwaites, D, Hansen, C, Deshpande, S, Phan, P, Franji, I, & Holloway, L. SU-E-T-370: Evaluating Plan Quality and Dose Delivery Accuracy of Tomotherapy SBRT Treatments for Lung Cancer. United States. https://doi.org/10.1118/1.4924731
Blake, S, Thwaites, D, Hansen, C, Deshpande, S, Phan, P, Franji, I, and Holloway, L. 2015. "SU-E-T-370: Evaluating Plan Quality and Dose Delivery Accuracy of Tomotherapy SBRT Treatments for Lung Cancer". United States. https://doi.org/10.1118/1.4924731.
@article{osti_22548420,
title = {SU-E-T-370: Evaluating Plan Quality and Dose Delivery Accuracy of Tomotherapy SBRT Treatments for Lung Cancer},
author = {Blake, S and Thwaites, D and Hansen, C and Deshpande, S and Phan, P and Franji, I and Holloway, L},
abstractNote = {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.},
doi = {10.1118/1.4924731},
url = {https://www.osti.gov/biblio/22548420}, journal = {Medical Physics},
issn = {0094-2405},
number = 6,
volume = 42,
place = {United States},
year = {Mon Jun 15 00:00:00 EDT 2015},
month = {Mon Jun 15 00:00:00 EDT 2015}
}