Variability in the amount of fluorine-18 fluorodeoxyglucose excreted in urine measured from oncology patients during PET/computed tomography imaging.

ABSTRACT

The objectives of this work were to estimate the amount of fluorine-18 fluorodeoxyglucose (F-FDG) excreted (AFE) in the patient urine during the uptake phase as percentage of the injected activity and to examine the effect of blood glucose levels (BGL) on the excreted amount and whether it varies among men and women using statistical analysis methods. Radiation dose rates were measured at 1 m from 50 patients, 24 men and 26 women, before and after the first void using a calibrated ionization chamber. The F-FDG was injected in the patients using a calibrated automatic dose injection system. Statistical analysis using hypothesis testing was carried out. Patients with BGL above 5 mmol/l had a higher AFE of 12.3% in comparison with 8.3% of the patients with BGL below 5 mmol/l. A statistically nonsignificant correlation (r=0.183, P<0.249) between AFE and BGL was found; a nonsignificant difference was found in the AFE measured among the male and female patients. The AFE measured was 12±6%, with a range of (2-30%). There was a wide variation in the first void time of 39±8 min, with a range of (17-68) min. A simple noninvasive measurement method is presented that enabled the estimation of the amount of F-FDG excreted from the patient during voiding. Statistical analysis concluded that the amount of F-FDG excreted does not depend on sex, but is perhaps influenced by BGL.