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Objective. Patients treated with radionuclide therapy usually require restrictions on certain activities for a period of time following treatment to optimise protection of the public and ensure the legal dose limit is not exceeded. Software may be used to calculate necessary restriction periods for an individual based on longitudinal dose rate measurements from the time of radiopharmaceutical administration. A spreadsheet program has been used for this purpose in Australian hospitals for the last two decades. However, this spreadsheet has a limitation in that it uses an approximation in the calculation of dose from a contact pattern, which affects the calculated restriction period. A computer program called Dorn was developed that provides the same functionality as the spreadsheet but without this approximation. Proffered radiation safety advice from Dorn and the spreadsheet were compared. Approach. Advice from the spreadsheet and Dorn were compared for 55 patients who underwent iodine-131 therapy for differentiated thyroid cancer. Main results. The restriction periods for caring for infants, close contact with children and sleeping with a partner were typically about 13 hours longer in Dorn than in the spreadsheet, but in some cases were over a week shorter or a month longer. Significance. If the Dorn program is used clinically in place of the spreadsheet, some patients will enjoy shorter restriction periods and the therapy provider can be more confident in their compliance with regulatory requirements and best practice. Dorn is freely available from https://doi.org/jg5f.

Agricultural pesticide use has come under an intensive attack from an environmentally aware society. The Environmental Protection Agency has placed restrictions on use of selected pesticides, including DDT. The use of pesticide is a paradox in itself. Without feasible alternative insecticide strategies, such as biological control, restrictions on the use of pesticides will decrease agricultural output and food costs will increase. However, with pesticide use, social costs in the form of environmental damages may occur. To make an equitable decision as to the future of pesticides, researchers and policy-makers have tried to determine the optimal level of use, optimal timing of application, extent of economic benefits, extent of social costs, and the effects on the economy of pesticide restrictions.