PERFORMANCE ASSESSMENT AND UNCERTAINTY EVALUATION OF A PORTABLE NAI-BASED DETECTION SYSTEM USED FOR THYROID MONITORING

• Type: Article in International Scientific Journal
• Date: 2012

Authors

Bento, J (Author) Other; Martins, B (Author) Other; Teles, P (Author) Other; Neves, M (Author) Other; Colarinha, P (Author) Other; Alves, F (Author) Other; Teixeira, N (Author) Other; Vaz, P (Author) Other; Zankl, M (Author) Other

Journal

Title: Radiation Protection Dosimetry

Vol. 151

Pages: 252-261

ISSN: 0144-8420

Publisher: Oxford University Press

Indexing

ISI Web of Knowledge - 4 Citations

Scopus - 5 Citations

Other information

Authenticus ID: P-002-74N

DOI: 10.1093/rpd/ncs011

Abstract (EN): This work aims at assessing the performance of a portable detection system, equipped with an NaI(TI) scintillation detector for in vivo thyroid monitoring, which was properly calibrated using an anthropomorphic neck phantom. The anthropomorphic physical phantoms commonly used for the efficiency calibration of in rho counters often present certain limitations regarding the geometry and the activity distribution. Therefore, the feasibility of these detection systems for in vivo monitoring should be assessed whenever possible. To accomplish this assessment, patients to whom Tc-99m and I-123 marked radiopharmaceuticals have been administered in the framework of nuclear medicine diagnostic procedures were monitored. As the biokinetic models of the administered radiopharmaceuticals are known, the time-dependent activity functions in the critical organs after administration are easily quantified. The measured activities in the thyroid using the NaI(TI) scintillation detector were compared with the estimated activities using the biokinetic models, in order to reach conclusion about the applicability of the portable scintillation counter for in vivo thyroid monitoring. The state-of-the-art Monte Carlo computer program PENELOPE and two voxel phantoms (male and female) were used to evaluate the overall uncertainties influencing the thyroid monitoring. A computational parametric study was performed to quantify the influence of several parameters in the activity quantification (neck-detector distance, thyroid shape, thyroid size and overlying tissue thickness), which allowed one to gain insight and to better understand the discrepancies between the calculated and measured activities.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 10