Premium
Poster — Wed Eve—41: VMAT for Prostate Cancer: Superior Organ Sparing to IMRT and Delivery Efficiency to Helical Tomotherapy
Author(s) -
Cheng J,
Wu JK,
Tsai CL,
Chao HL,
Tsai YC
Publication year - 2009
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.3244145
Subject(s) - tomotherapy , medicine , nuclear medicine , prostate cancer , rectum , radiation therapy , dosimetry , prostate , radiation treatment planning , cancer , radiology , surgery
Volumetric modulated arc therapy (VMAT) has been developed for the better dose conformity and shorter treatment time. This study is aimed to compare the dosimetric and treatment parameters between step‐and‐shoot intensity modulated radiation therapy (IMRT), helical tomotherapy (HT), and volumetric modulated arc therapy (VMAT). Eight patients with localized prostate cancer with the dosimetric plans of 5‐field IMRT, HT, and VMAT for their 78‐Gy definitive treatment formed the basis of the study. Treatment target was prostate and proximal seminal vesicles. The goals were minimum clinical target volume (CTV) dose ≥ 78Gy, and 95% of planning target volume (PTV) ≥ 78Gy in 39 fractions. Target comparison showed PTV V95% of 99.95±0.05% for VMAT, 99.84±0.21% for IMRT, and 99.39±0.49% for HT; maximum dose to PTV was 82.44±0.29Gy, 82.45±0.54Gy, 82.80±0.72Gy, respectively. The rectum V65Gy was 11.18±1.52% for VMAT, 13.77±1.68% for IMRT, and 8.44±1.13% for HT, respectively. The bladder V65Gy was 13.25±8.22% for VMAT, 16.51±11.05 % for IMRT, and 10.63±4.47% for HT, respectively. Total monitor units were 304.3±42.3 for VMAT, 335.8±19.0 for IMRT, and 3073.4±532.6 for HT, respectively. Treatment time was 2.47±0.10 minutes for VMAT, 3.71±0.29 minutes for IMRT, and 3.64±0.60 minutes for HT, respectively. The VMAT plans in all 8 patients met the quality assurance criteria of 3% and 3mm. In conclusion, VMAT is a practical technique with comparable target coverage, better organ sparing than IMRT, and superior treatment efficiency to HT in prostate cancer patients.