TY - JOUR
T1 - Clinically relevant quality assurance (QA) for prostate RapidArc plans
T2 - Gamma maps and DVH-based evaluation
AU - Cozzolino, M.
AU - Oliviero, C.
AU - Califano, G.
AU - Clemente, S.
AU - Pedicini, P.
AU - Caivano, R.
AU - Chiumento, C.
AU - Fiorentino, A.
AU - Fusco, V.
PY - 2014
Y1 - 2014
N2 - The aim of this paper is to evaluate clinically relevant quality assurance (QA) tests for RapidArc prostate patients. 26 plans were verified by the COMPASS system that provides an independent angle response and a reconstruction of dose distribution in patient CT model. Plan data were imported from treatment planning system via DICOM. The fluencies, measured by a 2D detector, were used by COMPASS to forward calculate dose in CT patients and reconstruct dose-volume-histogram (DVH). The gamma analysis was performed, using both the criteria 3%-3-mm and 2%-2mm, for the whole grid patient and the per-structure volume. A DVH-based analysis was accomplished for target and organs-at-risk (OAR). The correlation between gamma passing rates and DVH discrepancies was performed using Pearson's test. Sensitivity, specificity and accuracy of whole and per-structure gamma method were calculated.No significant DVH deviation was observed for target and OAR. Weak correlation between gamma passing rates and dosimetric deviations was observed, all significant r-values were negative. The whole gamma method shows lack of sensitivity to detect dosimetric deviations >5%. Instead, a better balance between sensitivity and specificity was obtained employing per structure gamma both with 3%-3mm and 2%-2mm criteria.Because of the poor correlation between DVH goals and gamma passing rates, we encourage the DVH-based gamma passing rates, when it is possible. At least, a gamma method specific for structure was strongly suggested.
AB - The aim of this paper is to evaluate clinically relevant quality assurance (QA) tests for RapidArc prostate patients. 26 plans were verified by the COMPASS system that provides an independent angle response and a reconstruction of dose distribution in patient CT model. Plan data were imported from treatment planning system via DICOM. The fluencies, measured by a 2D detector, were used by COMPASS to forward calculate dose in CT patients and reconstruct dose-volume-histogram (DVH). The gamma analysis was performed, using both the criteria 3%-3-mm and 2%-2mm, for the whole grid patient and the per-structure volume. A DVH-based analysis was accomplished for target and organs-at-risk (OAR). The correlation between gamma passing rates and DVH discrepancies was performed using Pearson's test. Sensitivity, specificity and accuracy of whole and per-structure gamma method were calculated.No significant DVH deviation was observed for target and OAR. Weak correlation between gamma passing rates and dosimetric deviations was observed, all significant r-values were negative. The whole gamma method shows lack of sensitivity to detect dosimetric deviations >5%. Instead, a better balance between sensitivity and specificity was obtained employing per structure gamma both with 3%-3mm and 2%-2mm criteria.Because of the poor correlation between DVH goals and gamma passing rates, we encourage the DVH-based gamma passing rates, when it is possible. At least, a gamma method specific for structure was strongly suggested.
KW - 3D gamma
KW - 3D quality assurance
KW - COMPASS system
KW - RapidArc prostate
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U2 - 10.1016/j.ejmp.2014.01.003
DO - 10.1016/j.ejmp.2014.01.003
M3 - Article
C2 - 24480527
AN - SCOPUS:84899490264
VL - 30
SP - 462
EP - 472
JO - Physica Medica
JF - Physica Medica
SN - 1120-1797
IS - 4
ER -