Background/Purpose: Radiotherapy (RT) volumes for anal cancer are large and of moderate complexity when organs at risk ( OAR) such as testis, small bowel and bladder are at least partially to be shielded. Volumetric intensity modulated arc therapy (VMAT) might provide OAR-shielding comparable to step-and-shoot intensity modulated radiotherapy (IMRT) for this tumor entity with better treatment efficiency. Materials and methods: Based on treatment planning CTs of 8 patients, we compared dose distributions, comformality index (CI), homogeneity index ( HI), number of monitor units (MU) and treatment time (TTT) for plans generated for VMAT, 3D-CRT and step-and-shoot-IMRT (optimized based on Pencil Beam (PB) or Monte Carlo ( MC) dose calculation) for typical anal cancer planning target volumes (PTV) including inguinal lymph nodes as usually treated during the first phase (0-36 Gy) of a shrinking field regimen. Results: With values of 1.33 +/- 0.21/1.26 +/- 0.05/1.3 +/- 0.02 and 1.39 +/- 0.09, the CI's for IMRT (PB-Corvus/PB-Hyperion/MC-Hyperion) and VMAT are better than for 3D-CRT with 2.00 +/- 0.16. The HI's for the prescribed dose (HI36) for 3D-CRT were 1.06 +/- 0.01 and 1.11 +/- 0.02 for VMAT, respectively and 1.15 +/- 0.02/1.10 +/- 0.02/1.11 +/- 0.08 for IMRT (PB-Corvus/PB-Hyperion/MCHyperion). Mean TTT and MU's for 3D-CRT is 220s/225 +/- 11MU and for IMRT (PB-Corvus/PBHyperion/MC-Hyperion) is 575s/1260 +/- 172MU, 570s/477 +/- 84MU and 610s748 +/- 193MU while TTT and MU for two-arc-VMAT is 290s/268 +/- 19MU. Conclusion: VMAT provides treatment plans with high conformity and homogeneity equivalent to step-and-shoot-IMRT for this mono-concave treatment volume. Short treatment delivery time and low primary MU are the most important advantages.

A fast radiotherapy paradigm for anal cancer with volumetric modulated arc therapy (VMAT) / Stieler, F; Wolff, D; Lohr, F; Steil, V; Abo-Madyan, Y; Lorenz, F; Wenz, F; Mai, S. - In: RADIATION ONCOLOGY. - ISSN 1748-717X. - 4:(2009), pp. 1-11. [10.1186/1748-717X-4-48]

A fast radiotherapy paradigm for anal cancer with volumetric modulated arc therapy (VMAT)

Lohr F;
2009

Abstract

Background/Purpose: Radiotherapy (RT) volumes for anal cancer are large and of moderate complexity when organs at risk ( OAR) such as testis, small bowel and bladder are at least partially to be shielded. Volumetric intensity modulated arc therapy (VMAT) might provide OAR-shielding comparable to step-and-shoot intensity modulated radiotherapy (IMRT) for this tumor entity with better treatment efficiency. Materials and methods: Based on treatment planning CTs of 8 patients, we compared dose distributions, comformality index (CI), homogeneity index ( HI), number of monitor units (MU) and treatment time (TTT) for plans generated for VMAT, 3D-CRT and step-and-shoot-IMRT (optimized based on Pencil Beam (PB) or Monte Carlo ( MC) dose calculation) for typical anal cancer planning target volumes (PTV) including inguinal lymph nodes as usually treated during the first phase (0-36 Gy) of a shrinking field regimen. Results: With values of 1.33 +/- 0.21/1.26 +/- 0.05/1.3 +/- 0.02 and 1.39 +/- 0.09, the CI's for IMRT (PB-Corvus/PB-Hyperion/MC-Hyperion) and VMAT are better than for 3D-CRT with 2.00 +/- 0.16. The HI's for the prescribed dose (HI36) for 3D-CRT were 1.06 +/- 0.01 and 1.11 +/- 0.02 for VMAT, respectively and 1.15 +/- 0.02/1.10 +/- 0.02/1.11 +/- 0.08 for IMRT (PB-Corvus/PB-Hyperion/MCHyperion). Mean TTT and MU's for 3D-CRT is 220s/225 +/- 11MU and for IMRT (PB-Corvus/PBHyperion/MC-Hyperion) is 575s/1260 +/- 172MU, 570s/477 +/- 84MU and 610s748 +/- 193MU while TTT and MU for two-arc-VMAT is 290s/268 +/- 19MU. Conclusion: VMAT provides treatment plans with high conformity and homogeneity equivalent to step-and-shoot-IMRT for this mono-concave treatment volume. Short treatment delivery time and low primary MU are the most important advantages.
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A fast radiotherapy paradigm for anal cancer with volumetric modulated arc therapy (VMAT) / Stieler, F; Wolff, D; Lohr, F; Steil, V; Abo-Madyan, Y; Lorenz, F; Wenz, F; Mai, S. - In: RADIATION ONCOLOGY. - ISSN 1748-717X. - 4:(2009), pp. 1-11. [10.1186/1748-717X-4-48]
Stieler, F; Wolff, D; Lohr, F; Steil, V; Abo-Madyan, Y; Lorenz, F; Wenz, F; Mai, S
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11380/1172443
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