Test-retest variability of high resolution positron emission tomography (PET) imaging of cortical serotonin (5HT(2A)) receptors in older, healthy adults

BACKGROUND: Position emission tomography (PET) imaging using [(18)F]-setoperone to quantify cortical 5-HT(2A )receptors has the potential to inform pharmacological treatments for geriatric depression and dementia. Prior reports indicate a significant normal aging effect on serotonin 5HT(2A )receptor (5HT(2A)R) binding potential. The purpose of this study was to assess the test-retest variability of [(18)F]-setoperone PET with a high resolution scanner (HRRT) for measuring 5HT(2A)R availability in subjects greater than 60 years old. Methods: Six healthy subjects (age range = 65–78 years) completed two [(18)F]-setoperone PET scans on two separate occasions 5–16 weeks apart. RESULTS: The average difference in the binding potential (BP(ND)) as measured on the two occasions in the frontal and temporal cortical regions ranged between 2 and 12%, with the lowest intraclass correlation coefficient in anterior cingulate regions. CONCLUSION: We conclude that the test-retest variability of [(18)F]-setoperone PET in elderly subjects is comparable to that of [(18)F]-setoperone and other 5HT(2A)R radiotracers in younger subject samples.