Setup reproducibility is crucial in the delivery of dose in radiotherapy as it determines the accuracy and treatment
success of the procedure. Previous studies reported supine as an alternative to prone; however, the comparison was
not straightforward as several factors… More
Setup reproducibility is crucial in the delivery of dose in radiotherapy as it determines the accuracy and treatment
success of the procedure. Previous studies reported supine as an alternative to prone; however, the comparison was
not straightforward as several factors were overlooked. This retrospective study attempted to determine the setup
reproducibility as measured by displacement of bony landmarks in the lateral, longitudinal, and vertical axes of supine
position relative to the standard prone position. Sixteen rectal cancer patients were positioned in supine (N=6) and
prone (N=10) as per radiation oncologists and medical physicists in 2018. On each daily fraction, the displacement of
the bony landmark in the three axes was calculated by the medical physicists and radiation therapists, and a total of 61
measurements were recorded. Results revealed that both supine and prone positions demonstrated an unacceptable
reproducibility value. The setup reproducibility did not significantly differ in both positions. Based on the results of the
study, the supine position, as reported by previous studies to exhibit superior setup reproducibility than prone position,
is still unacceptable in radiotherapy of rectal cancer patients. Less