A New Approach in the Construction of Protection in Brachytherapy – Brachytherapy Chamber

Brahiterapijski uređaji sa izvorima velike aktivnosti (> 370 GBq) postavljaju se u posebne zaštitne bunkere, debljine zaštitnog betonskog zida oko 70 cm, što zahteva opsežnije građevinsko-tehničke radove i povećava cenu izrade (preko 100.000 Eura). Da bi se prevazišao problem ograničenog prostora unutar odeljenja brahiterapije, predlažemo izradu „brahiterapijske komore“ koja bi bila smeštena u aplikacionoj sali minimalne površine 30 m2. Komandni pult brahiterapijskog uređaja bi se nalazilo u parapetom/paravanom odvojenom delu sale. Brahiterapijska komora, pojedinačnih dimenzija (V x Š) oko 2 m, u obliku ćiričnog slova P (П), izrađuje se od olovnih ploča debljine 5 cm. Sa jedne strane komore (ulaz za pacijenta) navlačiće se pokretni/motorizovani paravan (debljine zida: 5 cm; dimenzija V x Š oko 2,3 m). U toku zračenja pacijent i uređaj se nalaze u komori. Cena izrade ove brahiterapijske komore sa pripadajućim elementima ne bi prelazila cenu izrade klasičnog brahiterapijskog bunkera.Brachytherapy units with high activity sources (> 370 GBq) are placed in special protective treatment rooms, with concrete wall thickness of about 70 cm, which requires more extensive construction and technical works that increases the cost of production (over 100.000 Euros). In order to overcome the problem of limited space within the brachytherapy department, we propose construction of a "brachytherapy chamber" that would be located in the application teatre with a minimum area of 30 sqm. The control unit would be located in a separated part of the treatment room. The brachytherapy chamber, with an individual dimensions (H x W) of about 2 m, in the shape of the Cyrillic letter P (П), is made of lead plates 5 cm thick. On one side of the chamber (patient entrance) a movable/motorized screen (wall thickness: 5 cm; dimensions HxW each approx. 2.3 m) will be constructed. During radiation, the patient and theunit are in the chamber. The construction cost of this brachytherapy chamber with associated elements would not exceed the cost of making a classic brachytherapy treatment room.XXXII Simpozijum Društva za zaštitu od zračenja Srbije i Crne Gore, 4-6. oktobar 2023; Budva, Crna GoraProceedings: [https://vinar.vin.bg.ac.rs/handle/123456789/11602

A quantitative analysis of two-dimensional manually segmented transrectal ultrasound axial images in planning high dose rate brachytherapy for prostate cancer

Background/Aim. Prostate delineation, pre-planning and catheter implantation procedures, in high-dose rate brachytherapy (HDR-BT), are commonly based on the prostate manually segmented transrectal ultrasound (TRUS) images. The aim of this study was to quantitatively analyze the consistency of prostate capsule delineation, done by a single therapist, prior to each HDR-BT fraction and the changes in the shape of the prostate capsule during HDR-BT, using two dimensional (2D) TRUS axial image. Methods. A group of 16 patients were treated at the Medical System Belgrade Brachytherapy Department with definitive HDRBT. The total applied median dose of 52 Gy was divided into four individual fractions, each fraction being delivered 2– 3 weeks apart. Real time prostate axial visualization and the manual segmentation prior to each fraction were performed using B-K Medical ultrasound. Quantitative analyses, analysis of an area and shape were applied on 2D-TRUS axial images of the prostate. Area analyses were used to calculate the average value of the cross-sectional area of the prostate image. The parameters of the prostate shape, the fractal dimension and the circularity ratio of the prostate capsule contour were estimated at the maximum axial cross section of the prostate image. Results. The sample group consisted of four phases, each phase being performed prior to the first, second, third and fourth HDR-BT fraction, respectively. Statistical analysis showed that during HDR-BT fractions there were no significant differences in the average value of area, as well as in the maximum shape of prostate capsule. Conclusions. Quantitative analysis of TRUS axial prostate segmented images shows a successful capsule delineation in the series of manually segmented TRUS images, and the prostate maximum shape remaining unchanged during HDR-BT fractions