ISSN:
1619-7089
Keywords:
Oxygen-15 labelled water
;
Arterial input function
;
Biodistribution model
;
Radiation dosimetry
;
Effective dose
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract Models based on uniform distribution of tracer in total body water underestimate the absorbed dose from H2 15O because of the short half-life (2.04 min) of 15O, which leads to non-uniform distribution of absorbed dose and also complicates the direct measurement of organ retention curves. However, organ absorbed doses can be predicted by the present kinetic model based on the convolution technique. The measured time course of arterial H2150 concentration following intravenous administration represents the input function to organs. The impulse response of a given organ is its transit time function determined by blood flow and the partition of water between tissue and blood. Values of these two parameters were taken from the literature. Integrals of the arterial input function and organ transit time functions were used to derive integrals of organ retention functions (organ residence times). The latter were used with absorbed dose calculation software (MIRDOSE-2) to obtain estimates for 24 organs. From the mean values of organ absorbed doses, the effective dose equivalent (EDE) and effective dose (ED) were calculated. From measurements on 21 subjects, the average value for both EDE and ED was calculated to be 1.2 μSv · MBq−1 compared with a value of about 0.5 μSv · MBq−1 predicted by uniform water distribution models. Based on the human data, a method of approximating H2 15O absorbed dose values from body surface area is described.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00181069
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