Purpose: The Veneziaáµ€á´¹ gynecologic applicator (Elekta, Stockholm, Sweden) introduced in 2018 is a system of a tandem, two semi-circular ovoids with guide channels for interstitial needles and a perineal template. The purpose of this study is to report our early experience from the use of the Veneziaáµ€á´¹ applicator.
Methods: Retrospective data used from eighteen patients treated with the Veneziaáµ€á´¹ included 56 plans. Applications utilized 22mm, 26mm, and 30mm diameter ovoids, and 50, 60, or 70mm tandems with 30-degree inflection. Each application used between 6-16 interstitial needles, mostly through the ring guide channels, and through the perineal template in 2 cases. The prescription was 3000 cGy in 5 fractions. Point A and B values were recorded (GEC-ESTRO guidelines). Volumetrically, D90, D100, and V100 were target parameters. Critical structures included rectum, bladder, bowel, sigmoid, and vaginal wall. A conformation number (CN) was calculated for each fraction.
Results: The mostly used arrangement of the system was a 22mm ring and 70mm tandem length, with 2 straight and 2 flared needles on each ovoid (8 needles). In six cases, at least one needle was unloaded. The median of total dwell locations was 126.5; though this value increased in later applications due to increased numbers of needles and a switch of dwell spacing from 5mm to 2.5mm. The median HRCTV volume was 60.3cmÂ³ while the median volume of the 100% isodose line was 121.9cmÂ³. Median Point-A values were 975 and 935 cGy for left and right, respectively. Median percent doses to 2cmÂ³ bladder, rectum, sigmoid, and bowel were 79.6%, 61.2%, 64.9%, and 34.5%, respectively. The median CN was 0.453.
Conclusion: Using Veneziaáµ€á´¹ applicator has remarkably improved dosimetric goals when performing volumetric treatment planning for gynecologic brachytherapy boosts. This applicator has been preferentially used in cases which are known to have difficult or irregular targets.