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SU‐FF‐I‐78: Effective Doses in Whole Body and Brain PET/CT Procedures of Adult Patients
Author(s) -
AlHaj A,
Lobriguito A,
Parker R
Publication year - 2009
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.3181198
Subject(s) - medicine , nuclear medicine , effective dose (radiation) , body weight , dosimetry , radiology
Purpose: To determine the variation in patient effective doses for whole body and brain PET‐CT procedures and determine methods for dose optimization. Method and Materials: Demographic data (age, gender, and weight), CT exposure parameters and activity of 18F (FDG) were taken from patient records of 543 whole body and initial 54 brain PET/CT cases. PET Effective doses were estimated using the dose conversion coefficients for 18F (FDG) in ICRP Report No. 80. CT effective doses for the manufacturer's stated CTDI air were estimated using the IMPACT dose calculator. The Pearson correlation (p <0.0001) of PET effective doses with weight, age and 18F (FDG) activity was analyzed. Results: There are more male patients (55% and 61%) than females (45% and 39%) for whole body and brain procedures respectively. The mean age of patients for whole body is 47 ±18 years old and 34 ±16 years old for brain studies. The mean 18F (FDG) for whole body is 460 ± 130 MBq and 410 ± 45 Mbq for brain procedures. Pooling all ages, the mean effective doses are 8 ± 2 mSv and 10 ± 1mSv for whole body and brain respectively and dose correlate poorly with weight, age and activity. CT effective doses are in the range of 11 to 15 Msv. Conclusion: There is a wide variation in the 18F(FDG) activity which is about 30% of the mean activity. Standardization of activity can be formulated per weight or per age and a study of the setting image quality criteria and using low dose CT should be made. A dose conversion coefficient of 1.8 Msv per Gy can be used for whole body CT using 6 and 9 mGy CTDI to estimate effective dose.