A Comparison Between Revised Manchester Point A And Icru-89-Recommended Point A Definition Absorbed-Dose Reporting Using Ct Images In Intracavitary Brachytherapy For Patients With Cervical Carcinoma

PURPOSE: This study is a comparison between revised Manchester Point A and International Commission on Radiation Units and measurements (ICRU) 89 report-recommended Point A absorbed-dose reporting in intracavitary brachytherapy for patients with cervical carcinoma.METHODS AND MATERIALS: The retrospective dosimetric study is based on the data of 32 patients with cervical carcinoma treated with high-dose-rate brachytherapy. Patients received 21 Gy in three fractions (7.0 Gy X three fractions) to Point A (A(flange), revised Manchester definition). All the patients were replanned with a new Point A (A(icru89)) defined on CT images as per the American Brachytherapy Society/ICRU-89. The data collected were compared with the data obtained from Point A (A(flange)).RESULTS: When using the A(flange) plan normalization method, the mean dose of 0.1 cc, 1 cc, and 2 cc bladder volumes was 820.79 +/- 207.47 cGy, 654.66 +/- 152.69 cGy, and 588.91 +/- 136.35 cGy, respectively. Likewise, when using the ICRU-89 Point A(icru89) normalization method, the mean dose of 0.1 cc, 1 cc, and 2 cc bladder volumes was 869.30 +/- 224.67 cGy, 693.24 +/- 166.20 cGy, and 616.61 +/- 150.32 cGy, respectively. For the rectum, Point A(flange) normalization plans, the mean dose of 0.1 cc, 1 cc, and 2 cc volumes was 589.37 +/- 163.26 cGy, 487.51 +/- 126.03 cGy, and 442.70 +/- 111.43 cGy, respectively. Likewise, using the A(icru89) plan, the mean 0.1 cc, 1 cc, and 2 cc rectum volume was 625.07 +/- 171.31 cGy, 517.50 +/- 131.05 cGy, 464.94 +/- 121.81 cGy, respectively. The statistical mean difference of Total Reference Air Kerma rate, V-100 (cc), bladder, rectum and sigmoid, was found significant.CONCLUSIONS: It has been found that the position of revised Manchester (A(flange)) and ICRU-89 Point A does not match on CT images/radiograph, which resulted in variation in doses to the tumor, V-100 (cc), organ at risk, and Total Reference Air Kerma. (c) 2021 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.