Universität zu Köln

Schomaecker, Klaus, Sudbrock, Ferdinand, Fischer, Thomas, Dietlein, Markus, Kobe, Carsten, Gaidouk, Mark and Schicha, Harald (2011). Exhalation of I-131 after radioiodine therapy: measurements in exhaled air. Eur. J. Nucl. Med. Mol. Imaging, 38 (12). S. 2165 - 2173. NEW YORK: SPRINGER. ISSN 1619-7070

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Abstract

Purpose A considerable amount of radioiodine is exhaled after radioiodine therapy leading to unwanted radiation exposure through inhalation. This study focused on the concentration of radioactivity exhaled and its chemical nature. Methods Air exhaled by 47 patients receiving I-131-iodine for different thyroid diseases (toxic goitre n=26, Graves' disease n=13, thyroid cancer n=8) was investigated with a portable constant air-flow sampler. Different chemical iodine species were collected separately (organic, elemental and aerosolic) up to 26 h after administration of the radioiodine capsule. The data approximated to a monoexponential time-activity curve when integrated over 100 h. The radioactivity in the filters was measured with a well counter at defined time points after administration. Results The radioactivity of I-131 in the exhaled air 1 h after administration ranged from 1 to 100 kBq/m(3). Two parameters (half-life of radioiodine exhalation and time-integrated activity over 100 h) were substantially higher in patients with cancer after near-total thyroidectomy (11.8 +/- 2.1 h and 535 +/- 140 kBq / m(3), respectively) than in patients with hyperfunctioning thyroid tissue due to toxic adenoma (7.6 +/- 2.5 h and 115 +/- 27 kBq / m(3), respectively) or Graves' disease (6.4 +/- 3.6 h and 113 +/- 38 kBq / m(3), respectively). The percentage of radioiodine in the exhaled air in relation to radioiodine administered to the patient was between 80 ppm and 150 ppm. The fraction of organically bound radioiodine (mean value) for all time points after administration was 94-99.9%. This percentage did not depend on the type of thyroid disease. Conclusion The amount of exhaled radioiodine is small but by no means negligible on the first day after administration. This is the first study to provide experimental evidence on a systematic basis that radioiodine becomes exhalable in vivo, i.e. in the patient. The mechanism of organification of orally administered radioiodine remains to be investigated.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Schomaecker, Klaus UNSPECIFIED UNSPECIFIED UNSPECIFIED Sudbrock, Ferdinand UNSPECIFIED UNSPECIFIED UNSPECIFIED Fischer, Thomas UNSPECIFIED UNSPECIFIED UNSPECIFIED Dietlein, Markus UNSPECIFIED UNSPECIFIED UNSPECIFIED Kobe, Carsten UNSPECIFIED UNSPECIFIED UNSPECIFIED Gaidouk, Mark UNSPECIFIED UNSPECIFIED UNSPECIFIED Schicha, Harald UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-484362
DOI:	10.1007/s00259-011-1888-8
Journal or Publication Title:	Eur. J. Nucl. Med. Mol. Imaging
Volume:	38
Number:	12
Page Range:	S. 2165 - 2173
Date:	2011
Publisher:	SPRINGER
Place of Publication:	NEW YORK
ISSN:	1619-7070
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language DIFFERENTIATED THYROID-CARCINOMA; RADIATION-EXPOSURE; FAMILY-MEMBERS; HYPERTHYROIDISM; ABLATION; CANCER; DISEASES Multiple languages Radiology, Nuclear Medicine & Medical Imaging Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/48436