Dosimetric comparison study of three dimensional conformal radiotherapy (3dcrt) versus different intensity modulated radiotherapy (IMRT) techniques in prostate cancer treatment

Abstract

IMRT is a well-known and widely used treatment technique for carcinoma of the prostate (PCa) because it permits dose escalation to the tumour while sparing normal tissues. In Sri Lanka, along with IMRT, the 3DCRT technique is also used in the treatment of PCa. This study was carried out to compare 3DCRT treatment against SimultaneousIntegrated Boost Intensity Modulated Radiation Therapy (SIB-IMRT), Sequential IMRT, and Standard IMRT using dosimetric parameters such as Planning Target Volume (PTV) coverage by prescribed dose, Conformity Index (CI), Homogeneity Index (HI), percentage of maximum, minimum and mean dose to PTV and dose to 50% volume (D50) of the rectum, bladder, and femoral heads. Thirty-one PCa patients’ treatment plans were included in the study. For evaluation purposes, the Dose-volume Histograms (DVHs) were compared in all techniques. The D50 to femoral heads showed a significant difference (p < 0.05) in the 3DCRT technique against all IMRT techniques as the dose to femoral heads was significantly greater in 3DCRT therapy in many patients. SIB-IMRT showed a significantly higher PTV coverage and dose conformity in PTV than 3DCRT while the Sequential IMRT technique showed a greater homogeneity in PTV and critical organ sparing to 3DCRT technique. However, when considering other dosimetric parameters, there was no significant difference between 3DCRT and IMRT.