Establishing local diagnostic reference levels for adult whole-body PET/CT in Malaysia

The combination of positron emission tomography (PET) and computed tomography (CT) scanning has significantly transformed the field of nuclear medicine.

This study aims to establish local diagnostic reference levels (LDRLs) for adult positron emission tomography/computed tomography (PET/CT) scans utilizing three radiotracers:18F-fluorodeoxyglucose (18F-FDG), 68Gallium-prostate-specific-membrane-antigen (68Ga-PSMA), and 68Gallium-etraazacyclododecane-tetraacetic-acid-octreotide (68Ga-DOTATATE).

Demographic data, radiation dose information, scanner PET/CT system specifications, and acquisition protocols were collected from the Department of Nuclear Medicine at Penang Hospital in Malaysia. The LDRL was determined by calculating the 50th percentile.

The proposed LDRLs values for whole-body 18F-FDG, 68Ga-PSMA and 68Ga-DOTATATE scans were 264 MBq, 194.07 MBq, and 186.85 MBq, respectively. The proposed LDRL for the diagnostic CT parameters (CTDIvol and DLP) associated with whole-body 18F-FDG PET/CT scans were 4.04 mGy and 412.25 mGy.cm, while proposed LDRL values for 68Ga-PSMA and 68Ga-DOTATATE scans were 4.33 mGy and 452.16 mGy.cm, and 4.51 mGy and 468.69 mGy.cm, respectively.

The administered activity of 18F-FDG, 68Ga-PSMA, and 68Ga-DOTATATE examinations can be reduced without compromising or affecting the image quality. The proposed LDRL values for the CT parameters of the whole-body 18F-FDG examinations were the lowest among all compared values, but 68Ga-PSMA and 68Ga-DOTATATE examinations require further studies to optimize patient radiation doses in Malaysia and other regions while maintaining image quality.