Comparison of Contouring Results for Prostate Cancer Treatment Planning Obtained by Two Different Specialists
This study is a comparison of contoured diagnostic images derived from computed tomography (CT) and magnetic resonance imaging (MRI) by both a radiation oncologist (RO) and a radiologist (R) using volumetric modulated arc therapy (VMAT) and intensity modulated radiation therapy (IMRT) techniques.
CT and MRI sections of 16 patients were contoured by the RO and the R. Planning target volume (PTV) criteria assessed were conformity index (CI), homogeneity index (HI), volume covered by 98% isodose line (V 98%) and maximum dose (Dmax). In critical organs, 40 Gy organ area volume (V40),
65 Gy organ area volume (V65), and Dmean criteria were evaluated. Paired samples t-test was used for statistical analysis.
PTV and critical organs were compared. MRI PTV and bladder volume drawn by R were lower. Comparison
of CT images revealed IMRT plans were superior in terms of Dmax and CI, while V40 and Dmean
values for rectum and bladder were lower in MRI-based VMAT plans. In MRI plans, IMRT was superior
in terms of PTV, Dmax, CI, V65, and Dmean for critical organs; however, critical organs were well preserved
with both planning techniques.
There was some difference between contouring of the R and the RO, which was reflected in the treatment plans.