UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS

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2024-11-22 2:24
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Conference: Bucharest University Faculty of Physics 2004 Meeting


Section: Electricity and Biophysics


Title:
Quality Control of Brachytherapy implant


Authors:
VASILE Gabriel, M Sc*, POP Madalina, M Sc**, VLAD Stefanel, MD*


Affiliation:
* “Dr. C. Davila” Central Clinical Emergency Military Hospital – Bucharest, RO

** “Prof. Dr. Al. Trestioreanu” Institute of Oncology – Bucharest, RO


E-mail


Keywords:
Brachytherapy, gynecology implant, orthogonal/variable angles reconstruction.


Abstract:
Purpose: In Brachyterapy it is very important to know exactly absorbed dose at bladder and rectum to know exactly TCP (tumor control probability) and NTCP (normal tissue complication probability). The aim of this study is to analyse difference between calculated doses, for risk organs, using different reconstruction methods of brachyterapy implant. Methods and materials: 15 patients with gynecology neoplasm were included into this study. Patients were treated from January 20 to March 21in Radiotherapy Department of Military Hospital, Bucharest, Romania. In order to create virtual patient anatomy and applicator system is used, for all cases, simulator Simulix HP (Nucletron, Holland). It is taken two sets of imagines: orthogonal (A-P, L-R) and variable angles (usually 400 – 3150). In each radiography imagine are reconstructed patient points and catheter points. The reference patient points are defined from ICRU 38. Dose distribution at organ of risk (bladder and rectum) was calculated using PLATO Brachytherapy Planning System (v 4.10). Results: Using same distribution of radioactive sources, same point of dose prescription, same dose value, are compared, for each set of imagines, 3D dose distribution and special dose at reference point (bladder and rectum). The study shows difference between calculated doses at organ of risk for each reconstruction method of Brachytherapy implant. In all cases, calculated dose using orthogonal method was always less than calculated dose using variable angles method. Conclusions: Using orthogonal imagines can be defined better patient anatomy, but is very hard to reconstruct implant catheters. The best solution for reconstruction Brachytherapy implant is to use large number of imagines (orthogonal and variable angles). It is necessary to compare calculated data from treatment planning system with in vivo dosimetry data.