Biodistribution and radiation dosimetry of deuterium-substituted 18F-fluoromethyl-[1, 2-2H4]choline in healthy volunteers

• Published in: Journal of nuclear medicine (Chicago, Ill.) Vol. 55; no. 2; p. 256
• Main Authors: Challapalli, Amarnath, Sharma, Rohini, Hallett, William A, Kozlowski, Kasia, Carroll, Laurence, Brickute, Diana, Twyman, Frazer, Al-Nahhas, Adil, Aboagye, Eric O
• Format: Journal Article
• Language: English
• Published: United States 01.02.2014
• Subjects: Aged; Choline - analogs & derivatives; Choline - pharmacokinetics; Deuterium - pharmacokinetics; Female; Fluorine Radioisotopes - pharmacokinetics; Healthy Volunteers; Humans; Image Processing, Computer-Assisted; Male; Middle Aged; Multimodal Imaging - methods; Patient Safety; Positron-Emission Tomography - methods; Radiation Dosage; Radiometry - methods; Radiopharmaceuticals - pharmacokinetics; Sex Factors; Tissue Distribution; Tomography, X-Ray Computed - methods; Whole Body Imaging; dosimetry; 18F-D4-FCH; biodistribution
• ISSN: 2159-662X; 1535-5667
• DOI: 10.2967/jnumed.113.129577

(11)C-choline and (18)F-fluoromethylcholine ((18)F-FCH) have been used in patients to study tumor metabolic activity in vivo; however, both radiotracers are readily oxidized to respective betaine analogs, with metabolites detectable in plasma soon after injection of the radiotracer. A more metabolically stable FCH analog, (18)F-fluoromethyl-[1,2-(2)H4]choline ((18)F-D4-FCH), based on the deuterium isotope effect, has been developed. We report the safety, biodistribution, and internal radiation dosimetry profiles of (18)F-D4-FCH in 8 healthy human volunteers. (18)F-D4-FCH was intravenously administered as a bolus injection (mean ± SD, 161 ± 2.17 MBq; range, 156-163 MBq) to 8 healthy volunteers (4 men, 4 women). Whole-body (vertex to mid thigh) PET/CT scans were acquired at 6 time points, up to 4 h after tracer injection. Serial whole-blood, plasma, and urine samples were collected for radioactivity measurement and plasma radiotracer metabolites. Tissue (18)F radioactivities were determined from quantitative analysis of the images, and time-activity curves were generated. The total numbers of disintegrations in each organ normalized to injected activity (residence times) were calculated as the area under the curve of the time-activity curve normalized to injected activities and standard organ volumes. Dosimetry calculations were performed using OLINDA/EXM 1.1. The injection of (18)F-D4-FCH was well tolerated in all subjects, with no radiotracer-related serious adverse event reported. The mean effective dose averaged over both men and women (± SD) was estimated to be 0.025 ± 0.004 (men, 0.022 ± 0.002; women, 0.027 ± 0.002) mSv/MBq. The 5 organs receiving the highest absorbed dose (mGy/MBq) were the kidneys (0.106 ± 0.03), liver (0.094 ± 0.03), pancreas (0.066 ± 0.01), urinary bladder wall (0.047 ± 0.02), and adrenals (0.046 ± 0.01). Elimination was through the renal and hepatic systems. (18)F-D4-FCH is a safe PET radiotracer with a dosimetry profile comparable to other common (18)F PET tracers. These data support the further development of (18)F-D4-FCH for clinical imaging of choline metabolism.