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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-23 18:13 |
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Conference: Bucharest University Faculty of Physics 2016 Meeting
Section: Biophysics; Medical Physics
Title:
Dosimetric Evaluation of Conventional and 3D Conformal Brachytherapy Treatment of Cervix Cancer
Authors:
M. T. GEORGESCU (1), A. TANASE (2), M. DUMITRACHE (2), B. ILEANU (3), R. ANGHEL (1, 4)
Affiliation:
1) University of Medicine and Pharmacy “Carol Davila” Bucharest, Romania
2) Emergency Central Military Hospital “Carol Davila” Bucharest, Romania
3) The Bucharest University of Economic Studies, Romania
4) Institute of Oncology “Prof. Dr. Al. Trestioreanu” Bucharest, Romania
E-mail
georgescumihaiteodor@gmail.com
Keywords:
Brachytherapy, 3D conformal, computer tomography, treatment planning, ICRU38
Abstract:
The purpose of this study was to compare International Commission on Radiation Units and Measurements (ICRU) reference points, used in conventional brachytheraphy planning, with Computer Tomography (CT)-based volumetric calculations of radiation doses for target volumes and organs at risk in biopsy-proven cervix carcinoma patients.
For all patients we used CT-compatible Fletcher-Suit applicators and we performed both conventional and CT scanning. Sixty-one CT-based brachytherapy plans were dosimetrically analyzed. On the reconstructed CT images, the clinical target volumes (CTV) and organs at risk (OAR) were delineated. On the same images, the point A and ICRU 38 rectal and bladder reference-points were specified. Sigmoid reference points and volumes were also defined and evaluated during planning.
The target radiation dose prescribed at point A was 7.5 Gy for all the brachytherapy sessions, taking into account the recommended dose limits for the ICRU 38 bladder and rectum reference points. For the sigmoid, the limit point dose was considered to be the same as the one of the rectum.
After conventional planning, D90, D100, V90, V100, V150, and V200 were evaluated for the CTVs. Also, for the OARs volumes D01cc, D1cc, D2cc, D3cc and D5cc mean radiation doses were reported.
Conclusion: The results confirm that point A radiation dose prescription overestimates the target volume coverage. Also, for the OARs the dose is underestimated for the conventional ICRU 38 planning compared to CT-based brachytherapy plans. This suggests that brachytherapy needs to advance from a point-based (conventional) to a volume-based concept (3D conformal).
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