Bladder Wall Radiation Dose in Humans from Fluorine-18-FDOPA

• Published in: The Journal of nuclear medicine (1978) Vol. 37; no. 11; pp. 1850 - 1852
• Main Authors: Dhawan, Vijay, Belakhlef, Abdelfatihe, Robeson, William, Ishikawa, Tatsuya, Margouleff, Claude, Takikawa, Shugo, Chaly, Thomas, Kazumata, Ken, Margouleff, Donald, Eidelberg, David
• Format: Journal Article
• Language: English
• Published: Reston, VA Soc Nuclear Med 01.11.1996; Society of Nuclear Medicine
• Subjects: Adult; Biological and medical sciences; Brain - diagnostic imaging; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; Dihydroxyphenylalanine - administration & dosage; Dihydroxyphenylalanine - analogs & derivatives; Female; Fluorine Radioisotopes - administration & dosage; Humans; Male; Medical sciences; Middle Aged; Neurology; Radiation Dosage; Tomography, Emission-Computed; Urinary Bladder - diagnostic imaging; Urinary Bladder - radiation effects; Radionuclide study; Bladder function; Human; Nervous system diseases; Absorbed dose; Fluorodopa(18F); Parkinson disease; Basal ganglion; Cerebral disorder; Limit dose; Central nervous system disease; Degenerative disease; Dosimetry; Mathematical model; Extrapyramidal syndrome; Positron; Emission tomography
• ISSN: 0161-5505; 1535-5667

PET, in conjunction with 18F-fluorodopa (FDOPA), has become the standard technique to assess basal ganglia degeneration in patients with movement disorders. Based on published dosimetry data, the injected dose of FDOPA is limited to 111 Mbq (3 mCi) because of exposure to the bladder wall, which is the critical organ for such studies. These dosimetry studies are based on mathematical models for the bladder radioactivity accumulation and clearance when the subjects were asked to void approximately 2 hr after the intravenous injection of FDOPA. In this study, we improved the radiation dose estimate to the bladder wall using dynamic PET to image the bladder during the uptake phase as well as before and after voiding. The subjects were tested on a new protocol. They were hydrated preinjection and given a first bladder void break at 40 min postinjection and a second void at the end of study at 120 min. The MIRD model, applied to the data collected from 10 adults of both sexes, yielded an average absorbed dose of 0.15 +/- 0.08 mGy/MBq (0.57 +/- 0.28 rad/mCi). This absorbed dose is significantly lower than previous estimates and allows for FDOPA injections up to 333 Mbq (9 mCi).