Use of 99mTc-bicisate in activation studies by split-dose technique.
The properties of the brain single photon emission computed tomography (SPECT) tracer 99mTc-bicisate (ethyl cysteinate dimer) were examined in regard to its use in test-retest studies with short-interval, split-dose studies. The stimulus applied in these tests was a visual activation by a "flickering chessboard" pattern. We used a fast dynamic SPECT (Tomomatic 232) recording eight slices. Twelve volunteers were assigned to two groups for reproducibility control and stimulation experiments, respectively. All were examined on 2 days. On the first day, only one injection was given in the resting state (t = 0), while two recordings were performed (t = 30 and t = 100), simulating the course and timing of a full split-dose study. The average washout of 8.3 +/- 1.0% was used as a correction on the second-day study. On that day the first injection was given during rest exactly as on day 1, allowing an estimate of day-to-day reproducibility. The second injection was made either in a resting state identical to the first or during visual stimulation. All images were normalized to mean brain count value. Results were analyzed in predefined anatomical regions of interest (ROIs). The day-to-day reproducibility was fair, with only one ROI (inferior frontal cortex) showing a significant 2% decrease. The studies of day 1 revealed a regional difference in observed washout ranging in the applied cortical ROIs from 7.9 to 11.5%.(ABSTRACT TRUNCATED AT 250 WORDS)
Holm
S
S
Department of Clinical Physiology and Nuclear Medicine, Bispebjerg Hospital, Copenhagen, Denmark.
Madsen
P L
PL
Sperling
B
B
Lassen
N A
NA
D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging*; D002560:Cerebrovascular Circulation; D003545:Cysteine / Q000031:analogs & derivatives*; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015609:Organotechnetium Compounds / Q000008:administration & dosage; D015203:Reproducibility of Results; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
D015609:Organotechnetium Compounds; C059659:technetium Tc 99m bicisate; D003545:Cysteine