Scanning personnel for internal deposition of radioactive material with personnel contamination whole body friskers and portal monitors

The potential for using personnel contamination devices such as whole body friskers and portal monitors for internal contamination monitoring was evaluated. Internally deposited radioactive material is typically determined with whole body counting systems. Whole body counts have traditionally been performed on personnel when they report for work, on a periodic basis (i.e., annually), when an uptake is suspected, and on termination. These counts incur significant expense. The monitored personnel pass through whole body friskers and portal monitors daily. This investigation was performed to determine if the external contamination monitors could provide an alternative to the more Costly whole body counting. The ability to detect 1% of a DAC for critical radioisotopes was applied as a detection criteria for this investigation. The results of whole body counts were used to identify the typical internal contamination radionuclides. From this list, the radioisotopes that would be the most difficult to measure were identified. From this review, 60Co and 131I were determined to be the critical radionuclides. One percent of a DAC for each isotope was placed, one at a time, in a humanoid phantom. The phantom was placed in the whole body frisker and open-quotes countedclose quotes. The phantom was carried through the portal monitor at a speed equivalent to a person walking through the monitor. Frequency of detection was derived for both systems. Practical aspects of integrating this screening system with traditional internal dosimetry programs are discussed