Dual-isotope brain SPECT imaging with technetium-99m and iodine-123: clinical validation using xenon-133 SPECT.
Our phantom studies indicate that the energy resolution (9.7% FWHM) of a new three-headed single-photon tomograph (PRISM-3000) separates the distribution of 99mTc from 123I for 10% asymmetric or 15% or 10% centered 99mTc windows when combined with a 10% asymmetric 123I window. This technique is now applied to the simultaneous measurement of resting rCBF and changes induced by vasodilation (1 g acetazolamide) in 10 subjects with cerebrovascular disease. Resting and vasodilated 133Xe SPECT images were obtained first. Within 48 hr, 99mTc HMPAO was given at rest, acetazolamide injected, and after 20 min either [123I] IMP or [123I] HIPDM was administered. Subjects were scanned for 99mTc and 123I simultaneously using 10% asymmetric windows. Regression analyses demonstrated a linear relationship between 133Xe SPECT and dual-isotope SPECT measurements of lesion-to-cerebellum ratios in baseline (r = 0.92), vasodilated (r = 0.86) and rest-minus-vasodilated data (r = 0.85). Technetium-99m and 123I images obtained through dual-isotope imaging are by definition in perfect anatomic registration.
Devous
M D
MD
Nuclear Medicine Center, University of Texas Southwestern Medical Center, Dallas 75235-9061.
Payne
J K
JK
Lowe
J L
JL
D000086:Acetazolamide / Q000494:pharmacology; D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging*; D002560:Cerebrovascular Circulation; D002561:Cerebrovascular Disorders / Q000000981:diagnostic imaging / Q000503:physiopathology; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes; D007462:Iodobenzenes; D008297:Male; D008875:Middle Aged; D015609:Organotechnetium Compounds; D010091:Oximes; D019690:Technetium Tc 99m Exametazime; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D014664:Vasodilation / Q000187:drug effects; D014980:Xenon Radioisotopes
D007457:Iodine Radioisotopes; D007462:Iodobenzenes; D015609:Organotechnetium Compounds; D010091:Oximes; D014980:Xenon Radioisotopes; D019690:Technetium Tc 99m Exametazime; C036739:N,N,N'-trimethyl-N'-(2-hydroxy-3-methyl-5-iodobenzyl)-1,3-propanediamine; D000086:Acetazolamide