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ABSTRACT
Background
During radiotherapy, accurate treatment setup is key to accurate dose distribution to the target volume. The study aims to estimate random and systematic errors in prostate cancer (PCa) treatment setup using MV EPID vs. kV CBCT imaging techniques and propose a technique with minimal setup errors.
Method
Setup error results of the movement along the x, y, and z coordinates before and after patients’ PCa treatment were extracted from Academic Hospital archived electronic records. Fifty (50) patients' setup error results obtained during the MV EPID, and 50 obtained during kV CBCT from 2015-2023 were randomly selected. All 100 male patients were above 45 years of age. The random and systematic setup errors were calculated using independent Student's t-test. Setup errors were compared using a p-value with the threshold of statistically significant difference of p < 0.05.
Result
The random errors were 0.8176, 3.0112, and 1.5060 mm and the systematic errors were 0.115, 0.426, and 0.213 mm for the kV CBCT while corresponding values for the MV EPID were 0.5012, 14.062 and 8.550 mm and 0.071, 1.988 and 1.209 mm, respectively. No statistically significant difference was observed on x-axis movement (p = 0.0630). However, for y and z-axes statistically significant differences were established (p = 0.0022 and p = 0.0001). The kV CBCT random and systematic systems and the MV EPID systematic error setup errors had less than a 5mm limit enabling delivery of a 95% accurate dose to the prostate cancer.
Conclusion
The study demonstrated that the kV CBCT system is superior to the MV EPID system in prostate cancer management. kV CBCT enhances accuracy; this can reduce normal tissue irradiation by allowing tighter treatment margins and potentially improving clinical outcomes. The study recommends kV CBCT for hypofractionation radiotherapy during PCa treatment.