Could the treatment of differentiated thyroid carcinoma with 3.7 and 5.55 GBq of (131I)NaI, on an outpatient basis, be safe?
OBJECTIVE
The first objective of this study was to evaluate the radiological impact on relatives and the environment because of outpatient treatment of differentiated thyroid carcinoma with 3.7 and 5.55 GBq of (131I)NaI. The second objective was to determine, analyze, and evaluate whole-body radiation dose to caregivers, the production of contaminated solid waste, and the potentiality of radiation dose and surface contamination existing inside patients' households.


METHODS
Twenty patients were treated on an outpatient basis, taking into consideration their acceptable living conditions, interests, and willingness to comply with medical and radiation-safety guidelines. The caregivers themselves, as well as the potentiality of the radiation dose inside patients' residences, were monitored with a thermo-luminescence dosimeter. Surface contamination and contaminated solid wastes were identified and measured by using a Geiger-Müller detector.


CONCLUSIONS
Twenty-six monitored individuals received accumulated effective radiation doses of less than 1.0 mSv, and only one 2.8 mSv, throughout the 7 days of measurement. The maximum registered value for the potential of radiation dose inside all living areas was 1.30 mSv. The monitored surface contamination inside patients' dwellings showed a mean value of 4.2 Bq/cm for all surfaces found to be contaminated. A total of 2.5 l of contaminated solid waste was generated by the patients with 3.33 MBq of all estimated activity.


CONCLUSIONS
This study revealed that the treatment of differentiated thyroid carcinoma with 3.7 and 5.55 GBq of (131I)NaI, on an outpatient basis, can be safe when overseen by qualified professionals and with an adapted radiation-protection guideline. Even considering the radioiodine activity level and the dosimetric methodology applied here, negligible human exposure and a nonmeasurable radiological impact to the human environment were found.
Nuclear Medicine Center, Department of Radiology, Clinical Hospital, School of Medicine, University of São Paulo, Brazil. willegaignon@hotmail.com
José Willegaignon de Amorim
JW
de Carvalho
Marcelo
M
Sapienza
Carla
C
Ono
Tomoco
T
Watanabe
Maria Inês
MI
Guimarães
Ricardo
R
Gutterres
Maria Helena
MH
Marechal
Carlos
C
Buchpiguel
D000328:Adult; D000553:Ambulatory Care / Q000592:standards; D017028:Caregivers; D005190:Family; D005260:Female; D006798:Housing; D006801:Humans; D007457:Iodine Radioisotopes / Q000737:chemistry; D008297:Male; D008875:Middle Aged; D011829:Radiation Dosage; D011835:Radiation Protection; D011879:Radiotherapy Dosage; D012449:Safety; D012974:Sodium Iodide / Q000737:chemistry* / Q000627:therapeutic use*; D013964:Thyroid Neoplasms / Q000532:radiotherapy*; D013997:Time Factors; D014916:Whole-Body Irradiation
D007457:Iodine Radioisotopes; D012974:Sodium Iodide