| Abstract [eng] |
Cancer - oncologic disease, which affects the uncontrolled cell proliferation. Over the years, in the world is set about 2 and 3 million new cases of cancer. Of these cases, skin cancer accounts about 132,000 new patients in the world, and in Lithuania is about 1,800 new cases of skin cancer. This oncologic disease usually treated of superficial x-ray therapy [4-7]. To treat skin tumors in the facial area, usually required 3cm diameter applicator. Because 3cm diameter applicator usually is not included in the standard X-ray therapy system. Relevance of the this study is to determine, or the different thicknesses lead protection can be used to reduce the diameter of the acrylic applicator in the clinical practice. Research Master's work is carried out with x-ray therapy system GULMAY D3225 and 4cm diameter acrylic applicator and three different thicknesses of a lead shields: 1.9mm and 3.1mm thick lead alloys and 3.9mm thick leaded rubber. With this lead guards we was trying to reduce the radiation field from 4cm diameter up to 3cm diameter. Dose change before a lead protection and after lead protection evaluation was carried out with GAFCHROMIC XR – QA2 radiochromic film. To evaluate the selected geometry of lead protection impact scattering and absorption processes, was selected three different leaden protection. The aim of this work is investigate the photon scattering and absorption processes in the lead protection, which aims to reduce the exposure field size of the treatment procedure. The analysis of the processes of low-energy photon interactions with the material and evaluation of selected lead guards geometry influence diffusion and absorption processes, it was found that the 2D dosimetry is an effective and quick way to measure and evaluate the exposure doses. |
