Effective dose estimation for oncological and neurological PET/CT procedures

Abstract

BackgroundThe aim of this study was to retrospectively evaluate the patient effective dose (ED) for different PET/CT procedures performed with a variety of PET radiopharmaceutical compounds.PET/CT studies of 210 patients were reviewed including Torso (n = 123), Whole body (WB) (n = 36), Head and Neck Tumor (HNT) (n = 10), and Brain (n = 41) protocols with 18FDG (n = 170), 11C-CHOL (n = 10), 18FDOPA (n = 10), 11C-MET (n = 10), and 18F-florbetapir (n = 10). ED was calculated using conversion factors applied to the radiotracer activity and to the CT dose-length product.ResultsTotal ED (mean ± SD) for Torso-11C-CHOL, Torso-18FDG, WB-18FDG, and HNT-18FDG protocols were 13.5 ± 2.2, 16.5 ± 4.5, 20.0 ± 5.6, and 15.4 ± 2.8 mSv, respectively, where CT represented 77, 62, 69, and 63% of the protocol ED, respectively. For 18FDG, 18FDOPA, 11C-MET, and 18F-florbetapir brain PET/CT studies, ED values (mean ± SD) were 6.4 ± 0.6, 4.6 ± 0.4, 5.2 ± 0.5, and 9.1 ± 0.4 mSv, respectively, and the corresponding CT contributions were 11, 14, 23, and 26%, respectively. In 18FDG PET/CT, variations in scan length and arm position produced significant differences in CT ED (p < 0.01). For dual-time-point imaging, the CT ED (mean ± SD) for the delayed scan was 3.8 ± 1.5 mSv.ConclusionsThe mean ED for body and brain PET/CT protocols with different radiopharmaceuticals ranged between 4.6 and 20.0 mSv. The major contributor to total ED for body protocols is CT, whereas for brain studies, it is the PET radiopharmaceutical.

Determining and updating PET/CT and SPECT/CT diagnostic reference levels: A systematic review

“…The effective dose (E) was also reported for the majority of PET/CT, SPECT/CT, PET, SPECT and CT components associated with PET and SPECT procedures during NDRL surveys (Tables 2 and 3) (15,18,22,24,27,29,30) . The E from PET/CT and SPECT/CT is defined as the sum total of the radiation dose (mSv) from the A and from the CT components allowing quantification of total radiation exposure (Total E (mSv) = ENM +ECT) and radiation risk (52,53) .…”

“…The E method in PET/CT and SPECT/CT is calculated by multiplying each radiation dose by specific conversion coefficients assigned for the A and the DLP value for the CT dose (52) . Some researchers used the Monte Carlo software programme to calculate the E value for CT doses such as CT-Expo software version 2.1 and 2.4 (Medizinische Hochschule Hannover Germany) and ImPACT scan CTDI dosimetry software (version 1.0.4 with the National Radiological Protection Board (NRPB) SR250 dose data) (15,23,24,27) .…”

Application of 82Sr/82Rb generator in neurooncology

“…A coefficient for calculating an effective dose is 1.26 μSv/MBq using the tissue‐weighting factor of the International Commission on Radiological Protection (International Commission on Radiological Protection (ICRP), ). So, the total effective dose was 1.0–1.9 mSv per single injection in compare, for example, with about 7–9 mSv from injected 18 F‐FDG activity 370–450 MBq (Marti‐Climent et al, ; Quin, Dauer, Pandit‐Taskar, Scholder, & Dauer, ).…”

“…For transportation of 82 Sr/ 82 Rb-generator, a certified package design is used (Figure 1b). The scheme of elution system is shown in Figure 1c dose was 1.0-1.9 mSv per single injection in compare, for example, with about 7-9 mSv from injected 18 F-FDG activity 370-450 MBq (Marti-Climent et al, 2017;Quin, Dauer, Pandit-Taskar, Scholder, & Dauer, 2016).…”

Diagnostic reference levels for 18F‐FDG whole body PET/CT procedures: Results from a survey of 12 centres in Australia and New Zealand

“…Globally, more than 90% of PET/CT examinations are performed for oncological examinations and the remaining are carried out for cardiology, neurology and psychiatry . Since it's introduction in 2001 PET/CT, clinical practice has seen the utilization of the CT component for attenuation correction (AC), anatomical localization, and diagnostic CT . Inevitably, a concern with 18 F‐FDG whole‐body PET/CT imaging is due to the combination of the administered activity and the x‐rays from the CT used for AC and/or anatomical localization.…”