Occupational ingestion of P-32: the value of monitoring techniques to determine dose. A case report.

The purpose of this article is to described the analytical methods used to assess the internal dose from a P-32-labeled compound that was inadvertently ingested. Bioassay data, using the International Commission on Radiation Protection (ICRP)-30 model, enabled the calculation of internal dose. Whole body counting (WBC) and urinary measurement with liquid scintillation counting were utilized to estimate the amount of radioactive material deposited in body organs. This metabolic model assumes that 80% of the material ingested is absorbed through the gastrointestinal tract because P-32 is soluble. The time of the intake, a critical variable in this method, was estimated on the basis of urine contamination of clothing. Twenty-four-hour urine sampling over a 6-week period, coupled with daily WBC over the same period, was performed. Because P-32 does not emit photons, WBC relied on measuring the bremsstrahlung radiation produced as a result of interaction of beta radiation with the body's tissues. A P-32-spiked phantom was used as a control. Over the 6-week monitoring period, urinary results indicated an ingestion of 560 microCi of P-32, whereas WBC estimated on intake of 580 microCi. An assessment of the laboratory where the accident occurred indicated that approximately 600 microCi of radioactive phosphorous was missing. The total effective dose equivalent was estimated at 4.8 rem (48 mSv). On the basis of this study, the ICRP model appears to fit the data obtained from urine measurements and WBC. No symptoms were noted from the ingestion of 580 microCi. The committed organ doses were well within the occupational nonstochastic limits of 50 (0.5 Sv) permitted by the Nuclear Regulatory Commission. These results were confirmed by NUREG/CR-4884 and commercial software (CINDY). This report confirms the value of using the ICRP-30 model with urinary measurements and WBC to estimate the dose received as a result of ingestion of radioactive P-32.

Radiation safety in biological research laboratories.

Radioisotopes are used in countless experiments in recombinant biological research as tracers. The use of radioisotopes must be controlled to prevent unnecessary exposures to workers and the environment. This chapter outlines a detailed approach to radiation safety in the highly technical biological research setting.

Model for inactivation and disposal of infectious human immunodeficiency virus and radioactive waste in a BL3 facility.

A method is described for autoclaving low levels of solid infectious, radioactive waste. The method permits steam penetration to inactivate biologic waste, while any volatile radioactive compounds generated during the autoclave process are absorbed. Inactivation of radiolabeled infectious waste has been problematic because the usual sterilization techniques result in unacceptable radiation handling practices. If autoclaved under the usual conditions, there exists a high probability of volatilization or release of radioisotopes from the waste. This results in the radioactive contamination of the autoclave and the laboratory area where steam is released from the autoclave. Our results provide a practical method to inactivate and dispose of infectious radioactive waste. For our research, Bacillus pumilus spore strips and vaccinia virus were used as more heat-resistant surrogates of the human immunodeficiency virus (HIV). These surrogates were used because HIV is difficult to grow under most conditions and is less heat tolerant than the surrogates. In addition, B. pumilus has defined cell death values, whereas such values have not been established for HIV. Both B. pumilus and vaccinia virus are less hazardous to work with. The autoclave method is time efficient and can be performed by laboratory personnel with minimal handling of the waste. Furthermore, waste site handlers are able to visually inspect the solid waste containers and ascertain that inactivation procedures have been implemented.