A Critical Assessment of the Linear No-Threshold Hypothesis: Its Validity and Applicability for Use in Risk Assessment and Radiation Protection.

The Society of Nuclear Medicine and Molecular Imaging convened a task group to examine the evidence for the risk of carcinogenesis from low-dose radiation exposure and to assess evidence in the scientific literature related to the overall validity of the linear no-threshold (LNT) hypothesis and its applicability for use in risk assessment and radiation protection. In the low-dose and dose-rate region, the group concluded that the LNT hypothesis is invalid as it is not supported by the available scientific evidence and, instead, is actually refuted by published epidemiology and radiation biology. The task group concluded that the evidence does not support the use of LNT either for risk assessment or radiation protection in the low-dose and dose-rate region.

Management of Diabetes Mellitus Before 18F-Fluorodeoxyglucose PET/CT: A Nationwide Patient-Centered Assessment of Approaches to Examination Preparation.

PURPOSE: The aim of this study was to perform, from the patient's point of view, a nationwide assessment of nuclear medicine practices regarding diabetic management before 18F-fluorodeoxyglucose (FDG) PET/CT for oncologic indications. METHODS: This prospective observational study was exempt from institutional review board oversight. Sixty-five nuclear medicine scheduling lines (33 academic, 32 private practice, 12-17 in each of the five US regions) were called using a prewritten script under the guise of a nonexpert patient's family member about scheduling a patient with diabetes with "cancer" for FDG PET/CT. Each center was called three times on three different days. The following data were collected: (1) blood glucose threshold for rescheduling an examination, (2) when or if to stop various medications, (3) fasting requirements, and (4) time-of-day scheduling preferences. Withheld information was not specifically requested. Descriptive statistics were calculated. RESULTS: There were 195 phone calls (mean duration, 2.9 min; range, 2-6 min). Relevant information was often withheld; withholding rates were as follows: blood glucose threshold, 71% (138 of 195); short-acting insulin instructions, 30% (59 of 195); long-acting insulin instructions, 99% (193 of 195); metformin instructions, 88% (179 of 195); fasting duration, 37% (72 of 195); and time-of-day scheduling preference, 91% (177 of 195). Mean provided data were as follows: blood glucose threshold, 195 mg/dL (range, 150-210 mg/dL); short-acting insulin withholding, 4.9 hours (range, 4-8 hours); long-acting insulin withholding, 12 hours (range, 12-24 hours); fasting duration, 5 hours (range, 4-8 hours); and preferred examination time, 91% (177 of 195). When specified (n = 18), morning scheduling was preferred (8% [15 of 195] versus 2% [3 of 195]). CONCLUSIONS: Diabetes-specific information is commonly withheld by nuclear medicine call centers throughout the United States when discussing oncologic FDG PET/CT despite local and national policies indicating its importance.