{Reference Type}: Journal Article
{Title}: End-to-end delivery quality assurance of computed tomography-based high-dose-rate brachytherapy using a gel dosimeter.
{Author}: Tachibana H;Watanabe Y;Mizukami S;Maeyama T;Terazaki T;Uehara R;Akimoto T;
{Journal}: Brachytherapy
{Volume}: 19
{Issue}: 3
{Year}: May 2020 0
{Factor}: 2.441
{DOI}: 10.1016/j.brachy.2020.02.002
{Abstract}: The purpose of this study was to develop a novel quality assurance (QA) program to check the entire treatment chain of image-guided brachytherapy with dose distribution evaluation in a single setup and irradiation using a gel dosimeter.<BR>A polymer gel was used, and the readout was performed by magnetic resonance scanning. A CT-based treatment plan was generated using the Oncentra planning system (Elekta, Sweden), and irradiation was performed three times using an afterloading device with an Ir-192 source. The dose-response curve of the gel was created using 6-MV X-ray, which is independent of the source beams. Planar gamma images on a coronal plane along the source transport axis were calculated using the measured dose as a reference, and the calculated doses were used in several error simulations (no error; 2.0 or 2.5 mm systematic and random source dwell mispositioning; and dose error of 2%, 5%, 10%, and 20%).<BR>The dose-R2 (spin-spin relaxation rate) conversion table revealed that the uncertainty and dose resolution of 6-MV X-ray were better than those of Ir-192 and also constant between the three measurements. With the 3%/1 mm criteria, there were statistically significant differences between each pair of settings except dose error of 2% and 5%.<BR>This work depicts a simple and efficient end-to-end test that can provide a clinically useful tool for QA of image-guided brachytherapy. In this QA program, air kerma strength and dwell position setting could also be verified. This test can also distinguish between different types of error.