Estimation of Absorbed Dese Using Activity Measured by PET for Continuous Inhalation of C¹⁵O₂ and ¹⁵O₂

Abstract

In our positron emission tomography (PET) studies, mesurement is carried out during C^<15>O_2, ^<15>O_2 and C^<15>O gas inhalation. The radiation absorbed dose was estimated by the MIRD method from measured cumulative redioactivity in organs and remainder of the body. The radiation absorbed dose in 22 target organs including pharynx, larynx and trachea walls were estimated using the radioactive concentration in 7 source organs (brain, pharynx-larynx, trachea, lung, heart, liver and ramainder of the body). These radioactive concentrations in organs were measured by PET scan in a normal volunteer during continuous C^<15>O_2 and ^<15>O_2 inhalation. The effective dose equivalents for 22 minutes of inhalation were found to be 5.81×10^<-4> mSv/MBq for C^<15>O_2 at 157 MBq/min and 4.64×10^<-4> mSv/MBq for ^<15>O_2 inhaled at 294 MBq/min.