Dosimetric comparison of conventional, MR-based, robotic arm and helical linear accelerator devices in ultra hypofractionated prostate radiotherapy

In the last few years hypofractionation has gained popularity in the curative radiotherapy of prostate cancer. Dosimetric comparison of plans prepared with conventional (TrueBeam), MR-based (MRIdian), robotic-armed (CyberKnife) and helical (Radixact) linacs that can apply advanced radiotherapy techniques was made in this study. The applicability of the plans prepared was evaluated by performing multichannel local gamma analysis accompanied by radiochromic film dosimetry. All data were analyzed statistically. Treatment plans provided target volume and critical organ dose limitations. Radixact in terms of HI, CyberKnife in terms of GI and LDS, and TrueBeam, CyberKnife and Radixact in terms of CI were found to be significantly superior. The MRIdian plans in the parameters V36.25 Gy and V32.625 Gy of the rectum and bladder were found to be significantly superior. The TrueBeam plans in the parameters V18.125 Gy of the rectum and bladder were found to be significantly superior. Gamma analysis was performed for all treatment plans in multi-channel film dosimetry. Statistical results showed that all plans prepared using 4 different devices can be applied reliably in the clinic.