PO33 Presentation Time: 10:30 AM: Testing the Usability of the Vaginal Speculum Tongue Made of Polyetheretherketone Material in Brachytherapy by Dosimetry Method

Abstract

<h3>Purpose</h3> In the tandem + ovoid brachytherapy application, during the metallic speculum removing process after the vaginal packaging process, the positions of the sponges may change due to the spoon-shaped structure of the speculum, and this situation may cause not desired efficiency from the packaging process. In this project, we aimed to 3D printing of vaginal speculum tongues from polyetheretherketone (PEEK) material and make the dosimetric evaluation to assess usability during packing in gynecologic brachytherapy. <h3>Materials and Methods</h3> In this study, we designed a modular structure in which the upper and lower tongue can be easily separated from the handle similarly to the metallic vaginal speculum we use in our routine practice with no requirement to remove the speculum tongues from the patient after packaging. The tongues of the designed speculum were produced with PEEK material with a layer thickness of 200 microns using a 3D printer (Intamsys Technology Co. Ltd., Shanghai, China). To evaluate the radiation permeability of the produced speculum tongues, a phantom containing water was designed to perform dosimetric studies and 2 different dosimetric methods were used such as the treatment planning system (TPS) and Radiochromic Film Dosimeter system (Gafchromic: EBT3). TG43 and ACUROS BV algorithms are used as TPS. Prescribed dose (3 Gy) at the surface of phantom (side with the speculum) was calculated for a single source Dwell position in TPS using with ACUROS BV algorithm. The irradiation time was 631.1 seconds for both algorithms. The activity of the radioactive source was 11,086 Ci. The measured values that were obtained from the same points with different techniques were recorded and relations with each other were evaluated by using the Pearson Correlation test. In each measurement method, dose values were recorded in 4 different directions such as right (with no speculum), left (with speculum), up, and down. Dose-distance graphs were created for each direction from these values, and no break in the curve was detected on the side of the speculum tongue in phantom. This work was supported by Eskisehir Osmangazi University Scientific Research Projects Unit as project number TSA-2021-2143. <h3>Results</h3> The measurement values obtained from two different TPS algorithms and the film dosimetry method are given in Figure 1, and no significant difference was found in the statistical evaluation. The values obtained by using different methods show parallelism with each other, and no breakage was detected due to the speculum tongue. <h3>Conclusions</h3> In conclusion, all values obtained from TPS and radiochromic film dosimetry were parallel to each other. When the dose values at the same points and dose-distributions were evaluated, we concluded the speculum tongues we produced from PEEK did not have any negative effect on the dose distribution. However, this proposition needs to be supported by making more measurements with different dosimetry methods.