Japanese Journal of Radiological Technology

Verification of Dose Distribution in Cervical Cancer Brachytherapy Using Metal and Plastic Applicators

To validate the point-A dose and dose distribution of metal and resin applicators in comparison with those of TG-43U1. The metal and resin applicators consisting of tandem and ovoid were modeled by the egs_brachy. The doses to point A and dose distributions considering each applicator were calculated and compared to those of TG-43U1. The dose to point A considering the metal applicator was 3.2% lower than that of TG-43U1, but there was no difference in the dose to point A considering the resin applicator. The dose distribution considering the metal applicator was lower than that of TG-43U1 at all calculation points, but there was no difference in the dose distribution considering the resin applicator at almost all calculation points. In this study, the dose distribution considering the metal applicator was lower than that of TG-43U1 at all calculation points, but there was no difference in the dose distribution considering the resin applicator at almost all calculation points. Therefore, TG-43U1 can accurately calculate the dose distribution when changing from the metal applicator to the resin applicator.

Usefulness of Metal Artifact-reduced Reconstruction for Image-guided Brachytherapy for Cervical Cancer

To evaluate the usefulness of single-energy metal artifact reduction (SEMAR) for target delineation in brachytherapy for cervical cancer patients with metal hip implants. A series of four definitive brachytherapy sessions in the same patient was analyzed. At each brachytherapy session, the identical set of computed tomography images was subjected with or without SEMAR treatment. For both SEMAR-treated and -untreated sets, five radiation oncologists delineated the high-risk clinical target volume (HR-CTV), bladder, and rectum, for which the volume, Dice coefficient, and the dose volume parameters were compared between SEMAR-treated and -untreated datasets. The bladder volume was significantly greater in the SEMAR-treated datasets compared with the SEMAR-untreated datasets. Importantly, for the bladder, Dice coefficient among five radiation oncologists was significantly higher for the SEMAR-treated datasets compared with the SEMAR-untreated datasets. These effects of SEMAR treatment were not evident for HR-CTV and the rectum. These data indicate that SEMAR treatment contributes to improve delineation of the bladder in brachytherapy for cervical cancer patients with metal hip implants.

Effect of Brachytherapy Source Dwell Position on Dose Distribution in Cervical Cancer Therapy

To investigate the effect of different source dwell positions on dose distribution in the treatment of cervical cancer with brachytherapy. Treatment planning data for cervical cancer patients were used. Treatment plans were created at 1 mm intervals, varying up to 5 mm. For intracavitary brachytherapy and intracavitary and interstitial brachytherapy, the following dose parameters were evaluated: 90% high-risk clinical target volume (HR-CTV D In intracavitary brachytherapy, the HR-CTV D It was shown that a 1 mm change in the source dwell position can affect the dose by up to 2% or more. The accuracy of the source dwell position is very important and should be checked before using the device.

Analysis of Factors That Promote Awareness of Breast MRI Surveillance for Carriers of Hereditary Breast Cancer Risk Genes ( <i>BRCA1/2</i>)