Graduate Degree Type
Medical Dosimetry (M.S.)
Purpose: The purpose of this study is to retrospectively evaluate the quantitative difference of prostate SBRT boost between LINAC boost and CK boost treatments, with a primary plan using LINAC volumetric modulated arc therapy.
Materials and Methods: Nine prostate cancer patients were treated with a SBRT fractionated schedule of 21 Gy in 3 fractions, given every other day over the course of a week. The LINAC-BOOST were created by the researcher followed the same fractionation schedule, treatment volumes, OAR, and dose constraints as the original CK-BOOST treatment. The CK-BOOST was completed on the Multiplan (v14) TPS, while the LINAC-BOOST was planned in the Pinnacle (v4.6.1) TPS.
Results: The parameters that were measured in this study are planned tumor volume coverage, conformity index, gradient index, global hotspot, Dmin, organs-at-risk dose, observational study constraints, and treatment time. Results showed ideal PTV Dmin for the CK-BOOST plans and ideal OAR sparing for the LINAC-BOOST plans.
Conclusion: The study showed that both boost plans provided adequate PTV coverage and were able to meet most constraints equally. The CK-BOOST plans did however have a more optimal Dmin overall. Another positive aspect of CK was maintaining a lower OAR hotspot for cases with metal implants. On the other hand, LINAC-BOOST plans average beam on time was about a tenth of the CK plans. Men who are treated with either LINAC or CK SBRT for prostate boost are going to receive similar overall treatments with a higher biologically effective dose with CK.
Keywords: LINAC, Cyberknife, Comparison, Prostate, SBRT, Boost
Ornelas, Vicente Miguel, "A Quantitative Comparison of LINAC vs. Cyberknife for SBRT Prostate Boost: A Retrospective Study" (2022). Culminating Experience Projects. 174.