Development of Devices for Improving the Reducibility of Patient Positioning on a Breast Board

Huh, Soon Nyung; Cho, Woong; Park, Yang Kyun; Ha, Sung Whan

Abstract

PURPOSE: We wanted to improve the setup reproducibility of breast cancer patients when utilizing a commercially available breast board for radiation therapy. The breast board was modified by using a new head rest and 2 types of board fixation devices.
MATERIALS AND METHODS
A conventional head/neck rest was modified to be positioned in various slots of the breast board, and it was fabricated 1 cm thinner to provide more comfort to a patient when the patient's neck was rotated. This rest improves the uncertainty of the daily setup. Also, the sagging problems at the left and right sides became negligible with the two types of board fixation devices: (1) the stair type, and (2) the arm type. The first device consists of an upper/lower holder with 4 stair-types of grooves and 4 rectangular inserts. In order to cover the whole range of vertical setup of the breast board, 4 rectangular inserts were needed, and each covered 10 steps. The arm-type fixation device was also fabricated and attached to the breast board. It had two aluminum bars that were fixed by utilizing a lock-type of screw. These devises were evaluated with two volunteers in order to prove the effectiveness of the improved setup accuracy.
RESULTS
The developed cranio-caudal fixation device demonstrated that it could reduce the cranio-caudal error by nearly 55% compared to the old device. As for left-and-right inclination, the stair-type and arm-type fixation devices can reduce the relative inclination by nearly 80% and 90%, respectively, compared to the breast board without the fixation device.
CONCLUSION
It was verified that the developed devices were effective for positioning the patients and for avoiding inclination of the breast board.