Quantitation of 211At in small volumes for evaluation of targeted radiotherapy in animal models

• Published in: Nuclear medicine and biology Vol. 22; no. 1; pp. 45 - 54
• Main Authors: Johnson, E.L., Turkington, T.G., Jaszczak, R.J., Gilland, D.R., Vaidyanathan, G., Greer, K.L., Coleman, R.E., Zalutsky, M.R.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 1995; Elsevier
• Subjects: Animals; Astatine - analysis; Astatine - pharmacokinetics; Astatine - therapeutic use; Biological and medical sciences; Contrast media. Radiopharmaceuticals; Female; Medical sciences; Pharmacology. Drug treatments; Radiometry - methods; Rats; Tomography, Emission-Computed, Single-Photon; Performance evaluation; Test objet; Animal model; Associated technique; Rat; Rodentia; Central nervous system; Biochemistry; Bioavailability; Imagery; Photon; In vivo; Vertebrata; Mammalia; Astatine; Measurement technique; Subarachnoidal space; Computerized axial tomography; Radiopharmaceuticals
• ISSN: 0969-8051; 1872-9614
• DOI: 10.1016/0969-8051(94)00077-W

We have evaluated SPECT and two planar imaging methods, geometric mean (GM) and buildup factor (BF), for their potential to quantitate in vivo 211At distributions in rat spinal subarachnoid spaces using phantom studies. The use of medium-energy collimators and the small diameter (3 mm) of the subarachnoid space complicate quantitation. Net activities from distributions in various backgrounds were obtained using a large region of interest with background subtraction. Results showed quantitation accuracy within 10% for SPECT and BF in low backgrounds increasing to 25% at higher background levels while GM errors ranged from 20 to 45%. We have also obtained images of [ 211At]astatide distributions, administered intrathecally, in rats.