ESTRO 2024 - Abstract Book

S327

Beachytherapy - Physics

ESTRO 2024

263

Digital Poster

PTW OCTAVIUS Detector 1600 SRS is virtuous tool in commissioning of brachytherapy applicator

Vladimir Stserbakov

North-Estonia Medical Center Foundatiion, Radiotherapy, Tallinn, Estonia

Purpose/Objective:

Until now, in our brachytherapy department there has been a need to obtain more detailed information about the behavior of the source inside the applicator during its commissioning, and therefore in carrying out the treatment of patients. The purpose of this work is to solve this problem using teletherapy tools.

Material/Methods:

Venezia 22 (Flexitron, Elekta) applicator was fixed on central part of PTW OCTAVIUS 1600 SRS 2D-dimensional array, where 2.5 mm distance between detectors, by fixing stem (Figure, B). 3 cm plate of tungsten used for shielding of array electronics. Time of collecting charge is ~10 s per dwell-position. Detector maximal reading of array ~ 0.5 Gy. 3x3 detectors readings around all array maximal reading detector are used for calculation precise source position: 3 crossplane trendlines parabolas ja 3 inplane trendlines parabolas are calculated, which give 3 points of parabolas maxima for cross- and inplane directions (Figure, C). Finally, intersection of crossplane and inplane trendlines of maxima of projection of parabolas gives the coordinates for source position. Measured files (in .mcc format) imported to Excel program to perform quick results processing (3 min /20 dwell-position, using macros). The matching of found and library source coordinates was performed by two approaches: first, by using source path, and, second, using coordinate of holes for needles as markers.