On-Line Measurement of Exhaled [11C]CO2 During PET

• Published in: The Journal of nuclear medicine (1978) Vol. 41; no. 4; pp. 605 - 611
• Main Authors: Gunn, Roger N, Ranicar, Alex, Yap, Jeff T, Wells, Paula, Osman, Safiye, Jones, Terry, Cunningham, Vincent J
• Format: Journal Article
• Language: English
• Published: Reston, VA Soc Nuclear Med 01.04.2000; Society of Nuclear Medicine
• Subjects: Biological and medical sciences; Carbon Dioxide - analysis; Carbon Radioisotopes; Humans; Investigative techniques, diagnostic techniques (general aspects); Medical sciences; Monitoring, Physiologic - methods; Radionuclide investigations; Respiratory system; Scintillation Counting; Sensitivity and Specificity; Tomography, Emission-Computed; Radionuclide study; Human; Expired air; On line acquisition; Device; Carbon dioxide; Continuous measurement; Carbon; Monitoring; Blood; Positron; Emission tomography
• ISSN: 0161-5505; 1535-5667

The purpose of this study was to develop and evaluate a system for the continuous on-line measurement of expired 11CO2 during 11C PET studies. A detector system was developed that allowed continuous sampling of expired air during PET. Healthy volunteers (n = 4) underwent PET with [11C]CO2 during which expired air, tomographic tissue activity, and blood data were collected. The measured expired-air 11CO2 radioactivity time courses were filtered, and an envelope was extracted and compared with the time course of 11CO2/H11CO3 in blood. Good agreement was found between the shapes of the expired-air envelope and the time course in blood, enabling quantitative calibration against discrete blood samples. A system for the continuous monitoring of expired radioactivity during PET has been developed and evaluated with [11C]CO2. This monitoring enables the quantitative continuous measurement of 11CO2/H11CO3- in blood.