131I therapy in thyroid cancer and benign thyroid diseases: personal dose equivalent HP(10) assessment in patient’s close family members
Author(s)Carapinha, Maria João
Ferreira, Teresa C.
Tavares, António Barata
Full recordShow full item record
AbstractIntroduction - The aim is to quantify the personal dose equivalent HP(10) in the family members (FMs) of the patients (PATs) undergoing iodine-131 thyroid cancer (TC) therapy and benign thyroid diseases (BTD) and to compare the HP(10) values of children and adults. Methods - An observational study with convenience sampling was performed, including 83 FMs (59% ♂) of 48 PATs (72.9% ♀). All FMs wore a whole body TLD for 21 days and received instructions on radiation protection, based on Euratom recommendations. All FMs were provided with relevant instructions for TLD use and answered a questionnaire. Two groups were defined: Group-TC, included 65 FMs (5 children below the age of 10) of 37 PATs treated for TC with average (ᾱ) activity of 3434MBq (range 1110–5920MBq); Group-BTD included 18 FMs adults of 11 PATs treated for BTD with ᾱ activity of 336.4MBq (range 185–555MBq). The in-PATs of Group-TC were discharged 48h after therapy. All ethical principles of the investigation were respected. Results - When the PATs of Group-TC were discharged the ᾱ effective dose rate measured at a 1-metre distance was 10.4μSv/h (range 2–28μSv/h). The ᾱ value of HP(10) in FMs were: 0.14mSv (range 0.00-3.37mSv) for Group-TC and 0.37mSv (range 0.01-2.40mSv) for Group-BTD. The HP(10) value depended on the degree of relationship (p=0.008) and the age of the FMs (p=0.007). HP(10) of the FMs were moderately associated to administered activity (ρsp=-0.319; p=0.010) in Group-TC. No association was found between HP(10) FMs and the administered activity in Group-BTD (ρsp=0.139; p=0.583). Conclusions - The FMs of the PATs submitted 131I therapy for BTD received higher doses when compared to FMs of TC PATs. The HP(10) of the FMs depended to the degree of relationship and the age of the FMs. In the PATs submitted 131I therapy for BTD, the HP(10) of the FMs is not associated with the administered activity. The personal dose equivalent in these FMs does not reach the dose limits recommended by ICRP 97 and ICRP 94.
Carapinha MJ, Costa G, Ferreira TC, Salgado L, Vaz S, Ferreira R, et al. 131I therapy in thyroid cancer and benign thyroid diseases: personal dose equivalent HP(10) assessment in patient’s close family members. In: PRS 2017 – Conference "Proteção Radiológica na Saúde 2017", Instituto Superior Técnico (Lisboa), 27-29 de setembro de 2017.