Impact of radiocontaminants in commercially available iodine-123: dosimetric evaluation
Iodine-123 (/sup 123/I) is considered by some to be the radionuclide of choice for thyroid scintigraphy because of its ideal physical and biological characteristics and low radiation absorbed dose to the thyroid. However, commercially available /sup 123/I (p,2n) and (p,5n) have radiocontaminants. The MIRD formalism was used to estimate the absorbed dose to the thyroid for various age groups receiving recommended administered activities at the time of delivery and at two half-lives assuming radiocontamination levels specified by the suppliers. The calculations demonstrate that an /sup 131/I uptake with a technetium-99m scan at the time of delivery results in less absorbed dose to the thyroid than an /sup 123/I (p,2n) scan and uptake. At two half-lives the absorbed dose triples and becomes equivalent to the dose from an /sup 131/I scan. The absorbed dose from an /sup 123/I (p,5n) scan at two half-lives is higher than that of an /sup 123/I (p,2n) scan at the time of delivery. Iodine-123 capsules should not be decayed down in order to obtain a recommended pediatric administered activity. There appears to be no dosimetric advantage of commercially available /sup 123/I for thyroid scintigraphy for adults or most children.
- Research Organization:
- Georgetown Univ. Hospital, Washington, DC
- OSTI ID:
- 5205919
- Journal Information:
- J. Nucl. Med.; (United States), Journal Name: J. Nucl. Med.; (United States) Vol. 3; ISSN JNMEA
- Country of Publication:
- United States
- Language:
- English
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560161 -- Radionuclide Effects
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62 RADIOLOGY AND NUCLEAR MEDICINE
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
COUNTING TECHNIQUES
DAYS LIVING RADIOISOTOPES
DIAGNOSTIC TECHNIQUES
DOSES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
ENDOCRINE GLANDS
GLANDS
HALF-LIFE
HOURS LIVING RADIOISOTOPES
IMPURITIES
INTERMEDIATE MASS NUCLEI
IODINE 123
IODINE 131
IODINE ISOTOPES
ISOTOPES
LABELLED COMPOUNDS
NUCLEI
ODD-EVEN NUCLEI
ORGANS
RADIATION DOSES
RADIOISOTOPE SCANNING
RADIOISOTOPES
RADIOPHARMACEUTICALS
SCINTISCANNING
THYROID