The Human Monitoring Laboratory's new lung counter: calibration and comparison with the previous system and the Cameco Corporation's lung counter.
The Human Monitoring Laboratory has replaced its lung counting system with four large area (85 mm x 30 mm) HPGe detectors, electronics, and software. The system has been calibrated with the same lung set and phantom that was used to calibrate the Human Monitoring Laboratory's previous lung counting system and the Cameco Corporation's mobile lung counter. The performance characteristics (efficiency and sensitivity) of all three systems are compared, with the Human Monitoring Laboratory's new system being more sensitive than the other systems by factor of 1.3. The large area detectors highlight the design deficiency of the Lawrence Livermore National Laboratory's torso phantom, namely short lungs, as the lower two detectors are over inactive tissue (approximately 40%). As a result, both a two-detector and a three-detector array are actually more sensitive than a four-detector array in certain circumstances. This is, however, an unrealistic finding as human lungs are much longer (approximately 10 cm) than the Lawrence Livermore National Laboratory's phantom's lungs. The dosimetric implications of the new system's minimum detectable activities are put into perspective using (57)Co, (235)U, (238)U, (239)Pu, (241)Am, and natural uranium as example radionuclides.
Kramer
Gary H
GH
Human Monitoring Laboratory, Environmental Radiation Hazards Division, Radiation Protection Bureau, Ottawa, Ontario, Canada. gary_kramer@hc-sc.gc.ca
Hauck
Barry M
BM
D000396:Air Pollutants, Radioactive / Q000032:analysis*; D001822:Body Burden; D002138:Calibration; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008168:Lung; D011829:Radiation Dosage; D011834:Radiation Monitoring / Q000295:instrumentation* / Q000379:methods / Q000592:standards; D011835:Radiation Protection / Q000295:instrumentation* / Q000379:methods; D011868:Radioisotopes / Q000032:analysis*; D012062:Relative Biological Effectiveness; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014915:Whole-Body Counting / Q000295:instrumentation* / Q000379:methods*
D000396:Air Pollutants, Radioactive; D011868:Radioisotopes