Application of a new method for patient positioning based on optical surface monitoring technology to head radiotherapy / 中华放射医学与防护杂志

ABSTRACT

Objective:To develop a new method to set up patients using optical surface monitoring system and to compare it with the conventional method in head radiotherapy.Methods:A total of 358 set-ups (130 with the conventional method and 228 with the new method ), which were from 99 head tumor patients in Beijing Cancer Hospital treated between May 2018 to April 2019, obtained by using Image Guided Radiotherapy were retrospectively analyzed. The distributions of set-up errors, the number of abnormal positions, and the set-up time were compared to evaluate the potential advantages of the new method .Results:The mean (± standard deviation) absolute values of setup errors of the new method were (0.07±0.07) , (0.08±0.06) and (0.06±0.06) cm for the vertical, lateral, and longitudinal, (0.53±0.41)°, (0.59±0.44)° and (0.59±0.46)° for the rotation, pitch and roll, respectively. In the new method , the setup accuracy was improved( t=3.24-6.10, P<0.001)and the number of abnormal positions was greatly reduced(χ 2=60.66, P<0.001). Compared with the conventional method, the patient setup time was slightly reduced by the new method , but the difference was not statistically significant ( P>0.05). Conclusions:The new high-precision method to set up patients using optical surface monitoring system improves the accuracy of patients′ position, decreases the corrections applied by 6DoF couch, reduces the probability of abnormal positions, and suggests the potential benefit in head radiotherapy.