In vivo determination of radiation dose in kidneys and bladder during renogram: a new approach.
The radiation dose absorbed by a patient from a radiopharmaceutical is usually calculated with the help of the equations published by the Society's Medical Internal Radiation Dose (MIRD) Committee and the use of a Reference Man. However, the (MIRD) estimations are based on the assumption that the patient is a normal subject with the characteristics of the Reference Man. This is not always true particularly in some pathological situations which present large deviations from normal. The purpose of this paper is to determine the dose in kidneys and bladder, during renograms, on the basis of real data. A protocol is formulated by means of which the processing of the frames acquired in the various stages of the renogram enables the determination of the kidney and bladder mass as well as the time distribution of radioactivity in these organs. Our results are in accordance with MIRD estimations for normal cases, whereas very significant deviations are observed in pathological ones. This is due to the fact that the mass of the 'source' and 'target' organs as well as the biodistribution of the radiopharmaceuticals are essential in the dose determination and large deviations are expected between estimated and real doses when in some pathological cases the mass of kidney is particularly reduced or its clearance retarded.
Nikiforidis
G
G
Department of Medical Physics, University of Patras, Rio-Patras, Greece.
Karatrandou
A
A
Vassilakos
P
P
D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D007668:Kidney / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D008961:Models, Structural; D011829:Radiation Dosage; D011866:Radioisotope Renography / Q000379:methods*; D016284:Technetium Tc 99m Pentetate; D001743:Urinary Bladder / Q000000981:diagnostic imaging*
D016284:Technetium Tc 99m Pentetate