Dosimetric evaluation of the feasibility of utilizing a reduced number of interstitial needles in combined intracavitary and interstitial brachytherapy for cervical cancer. Issue 2 (10th November 2022)

• Record Type: Journal Article
• Authors: Jahan, Dishary; Ahmad, Salahuddin; Thompson, Spencer; Schnell, Erich
• Is Part Of: Journal of applied clinical medical physics. Volume 24:Issue 2(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-11-10
• Subjects: brachytherapy -- cervical carcinoma -- combined interstitial/intracavitary -- high dose rate -- Venezia; Medical physics -- Periodicals; Clinical medicine -- Periodicals; Health Physics; Clinical Medicine; Electronic journals; Periodicals; Periodicals; Fulltext; Internet Resources; 610.153
• DOI: 10.1002/acm2.13833
• Languages: English
• ISSNs: 1526-9914

Abstract

Abstract: Purpose: To evaluate the ability of the Venezia advanced multichannel tandem and ring applicator to consistently produce dosimetrically comparable plans utilizing a reduced number of needle channels, to reduce the risk of secondary complications when boosting cervical cancer treatments with high dose rate (HDR) brachytherapy. Methods: We evaluated 26 fractions from 13 patients who were treated with HDR brachytherapy using the Venezia (Elekta) applicator. The original plans included a full load of 12–16 needles, including both parallel and 30‐degree oblique needles. We replanned each original to nine new configurations, with a reduced number of two, three, four, or six needles. Comparisons included differences in percentage dose coverage to 90% of the high‐risk clinical target volume, and percentage dose to 2 cm 3 of the bladder, rectum, sigmoid, and bowel. We considered new plans "passing" if they remained within our standards ( D 90 > 100%; D 2 cm 3 < 85% bladder, <65% rectum, sigmoid, bowel) or did not perform worse than original. Results: Removing only the two most anterior or the two most posterior needles from both sides showed 80.8% and 61.5% overall passing rate. Removal of the most anterior and posterior four needles together showed 65.4% overall passing rate. Removing all oblique needles showed 19.2% overall passing rate. Removing only left‐sided or only right‐sided oblique needles showed 46.2% and 23.1% overall passing, respectively. Removing only right‐sided or only left‐sided parallel needles separately showed 19.2% and 34.6% overall passing, respectively. Removing all parallel needles showed 11.5% overall passing rate. Conclusions: As only two replans required a full needle load to maintain dosimetric quality and 40 (76.9%), 36 (34.6%), 18 (69.2%), and 10 (19.2%) replans passed with 2, 3, 4, and 6 needles removed respectively, this indicates the potential for using a lesser number of interstitial needles during combined intracavitary and interstitial HDR brachytherapy while maintaining dosimetric quality.