Open AccessA dosimetric evaluation of knowledge‐based VMAT planning with simultaneous integrated boosting for rectal cancer patients
Author(s) -
Wu Hao,
Jiang Fan,
Yue Haizhen,
Li Sha,
Zhang Yibao
Publication year - 2016
Publication title -
journal of applied clinical medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.83
H-Index - 48
ISSN - 1526-9914
DOI - 10.1120/jacmp.v17i6.6410
Subject(s) - medicine , nuclear medicine , wilcoxon signed rank test , multileaf collimator , dose volume histogram , colorectal cancer , radiation treatment planning , radiology , cancer , radiation therapy , mann–whitney u test
RapidPlan, a commercial knowledge‐based optimizer, has been tested on head and neck, lung, esophageal, breast, liver, and prostate cancer patients. To appraise its performance on VMAT planning with simultaneous integrated boosting (SIB) for rectal cancer, this study configured a DVH (dose‐volume histogram) estimation model consisting 80 best‐effort manual cases of this type. Using the model‐ generated objectives, the MLC (multileaf collimator) sequences of other 70 clinically approved plans were reoptimized, while the remaining parameters, such as field geometry and photon energy, were maintained. Dosimetric outcomes were assessed by comparing homogeneity index (HI), conformal index (CI), hot spots (volumes receiving over 107% of the prescribed dose,V 107 %), mean dose and dose to the 50% volume of femoral head ( D mean _ FHandD 50 % _ FH), and urinary bladder ( D mean _ UBandD 50 % _ UB), and the mean DVH plotting. Paired samples t ‐test or Wilcoxon signed‐rank test suggested that comparable CI were achieved by RapidPlan ( 0.99 ± 0.04 forPTV boost, and 1.03 ± 0.02 for PTV) and original plans ( 1.00 ± 0.05 for PTV boostand 1.03 ± 0.02 for PTV), respectively ( p > 0.05 ) . Slightly improved HI of planning target volume (PTV boost) and PTV were observed in the RapidPlan cases ( 0.05 ± 0.01 for PTV boost , and 0.26 ± 0.01 for PTV) than the original plans ( 0.06 ± 0.01 for PTV boostand 0.26 ± 0.01 for PTV), p < 0.05 . More cases with positive V 107 %were found in the original (18 plans) than the RapidPlan group (none). RapidPlan significantly reduced theD 50 % _ FH(by1.53 Gy / 9.86 %from 15.52 ± 2.17 to 13.99 ± 1.16 Gy ),D mean _ FH(by1.29 Gy / 7.78 %from 16.59 ± 2.07 to 15.30 ± 0.70 G),D 50 % _ UB(by4.93 Gy / 17.50 %from 28.17 ± 3.07 to 23.24 ± 2.13 Gy ), andD mean _ UB(by 3.94 Gy / 13.43 % from 29.34 ± 2.34 to 25.40 ± 1.36 Gy ), respectively. The more concentrated distribution of RapidPlan data points indicated an enhanced consistency of plan quality. PACS number(s): 87.55.de; 87.55.dk