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The aim of this audit was to compare the data from the Wellington Blood and Cancer Centre (WBCC) with international reported experience by quantifying the dosimetric impact of interstitial needles on target coverage and organ at risk (OAR) doses.All patients identified as having had interstitial needles as part of their treatment out of a cohort of 120 radically treated cervical cancer patients between 2013 and 2019 were included. Each patient acted as their own control with two treatment plans optimised for each fraction; the clinically treated plan and a re-optimisation without the use of interstitial needles. Plan optimisation was completed according to the departmental protocol and cumulative equivalent doses for 2 Gy fractions (EQD2) were calculated.Eighteen patients were suitable for evaluation. A total of 52 insertions with interstitial needles were performed, of the 148 needles inserted, 119 (80.4%) were loaded. HRCTV D90% coverage mean was EQD2 5.4 Gy (0.5-10.6 Gy) higher for the course containing loaded interstitial needles, while no significant change was observed with regards to OAR doses. This improved coverage is in line with international standards which report 4.4-9.0 Gy.WBCC's early experience of interstitial cervix brachytherapy has shown our target coverage improvements meet previously published international standards and confirms the value of this technique. This audit supports ongoing use of interstitial needles at the WBCC.

A custom balloon applicator was created to deliver intracavitary high‐dose‐rate brachytherapy to a patient with a superficial vaginal cancer. The patient was unable to be treated conventionally due to an extremely narrow introitus that prevented the introduction of a conventional cylinder applicator. The custom applicator was constructed by inserting a straight titanium tandem applicator through the drainage lumen of a Foley catheter. The applicator was inserted and the catheter balloon was inflated when positioned at the vaginal apex. Three brachytherapy treatments were performed using this technique. Individual balloon eccentricities resulted in small radial tandem offsets within the balloon. This phenomenon was exploited by orientating the tandem offset in the direction of the target volume. Acceptable dosimetry was achieved for all fractions and the procedure was very well tolerated. The custom applicator was a viable solution that was safely developed in a short time frame using equipment readily available in our department.