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| Format: | Artículo científico |
| Language: | en |
| Published: |
Sociedade Brasileira de Proteção Radiológica - SBPR
2023
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| Online Access: | https://www.redalyc.org/articulo.oa?id=722277919005 https://www.redalyc.org/journal/7222/722277919005/ https://www.redalyc.org/journal/7222/722277919005/html/ https://www.redalyc.org/journal/7222/722277919005/722277919005.epub https://www.redalyc.org/journal/7222/722277919005/movil https://doi.org/10.15392/2319-0612.2023.2259 |
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Table of Contents:
- Application of OSL strips in CT dosimetry according to the AAPM methodology R. A. Terini J. D. Oliveira E. M. Yoshimura Biología OSL strips Dose profiles AAPM methodology equilibrium doses Computed tomography (CT) images contribute to high-quality medical diagnosis, but radiation dose can be quite high, requiring accurate assessment. CT dose index (CTDI) was developed for dosimetric purposes, but for scanners operated exclusively in axial mode. Nowadays, CTDI underestimate patient dose in helical CT exams. AAPM report TG111 (2010) suggested a new metric in which the patient's radiation dose is obtained from dose profiles constructed from several measurements made with a small ionization chamber. It is also possible to obtain dose profiles using properly calibrated OSL (optically stimulated luminescence) strips. The main objective of the present work is to contribute to optimizing CT dosimetry, comparing dose profiles obtained with OSL strips with measurements obtained by other authors. In this work, a "pencil" ionization chamber and 20 cm x 0.3 cm OSL strips were X-ray-irradiated, in air and in the holes of two cylindrical CT phantoms, using 100, 120, 140 kV peak voltages, both in lab and in a clinical CT scanner. Irradiated strips were read using an OSL reader built in the GDRFM. OSL profiles were calibrated against ionization chamber. From them, CTDIw and CTDIvol values were determined, differing approximately 3.9% from those of the CT scanner. From the profiles, also the planar equilibrium dose Deq,p (TG111) was evaluated in some CT protocols; Deq,p exceeded the CTDI values from the CT scanner in every case. E.g.: The percentage difference between Deq,p and CTDIvol for the head phantom ranged between 33-25%. Thus, in some cases, it could be advantageous to use calibrated OSL dosimeters instead of ionization chambers to obtain the profiles, saving time, because it is possible to obtain five OSL profiles from a single phantom irradiation. 2023 artículo científico 2319-0612 https://www.redalyc.org/articulo.oa?id=722277919005 https://www.redalyc.org/journal/7222/722277919005/ https://www.redalyc.org/journal/7222/722277919005/html/ https://www.redalyc.org/journal/7222/722277919005/722277919005.epub https://www.redalyc.org/journal/7222/722277919005/movil https://doi.org/10.15392/2319-0612.2023.2259 en http://www.redalyc.org/revista.oa?id=7222 Brazilian Journal of Radiation Sciences application/pdf Sociedade Brasileira de Proteção Radiológica - SBPR Brazilian Journal of Radiation Sciences (Brasil) Num.2 Vol.11