Wholebody Counting Intercomparison - 2003

Results and Discussion

The identities and activities of the radionuclides used in this year's intercomparison programme are given in Table 1. The activities have been decay corrected to the date of counting at each facility when evaluating bias. Participant results are shown in Table 2. These data are also available on the HML's website. Table 3 provides information about the radionuclides used in the phantoms and references the certificates obtained from the manufacturers that are attached to this report.

Size dependency:
Table 2 shows that either the size dependent calibration factors in use at each facility or the geometry independence of the WBC is sufficient to give results that are within the acceptable limits (given above) for PFB PFC and PF-_Acc.

Identification of unknown internal contaminants:
All identifications were correct (PFB, PF-_Acc, PFC, PME, PM-_Acc1, PMG) for all facilities, except facility D who did not report the ⁵⁷Co in PF-_Acc.

Accuracy of counting:
Table 2 shows that all results (PFB, PF-_Acc, PFC, PME, PM-_Acc1, PMF) are within the acceptable limits given above for all facilities, except facility D who did not report the ⁵⁷Co in PF-_Acc.

All but one of the bias results for Facilities A, J and M are positive, perhaps indicating a systematic error in the calibration curve. All but one of the bias results for Facility C are negative, perhaps indicating a systematic error in the calibration curve.

All facilities satisfy the accuracy requirements for the Overall Relative Bias, except facility D who did not report the ⁵⁷Co in PF-_Acc.

Location dependency:
Location dependence (PM-_Acc1 and PF-_Acc) does not seem to be a factor for all facilities. Table 2 shows that the activities were estimated within acceptable limits given above, except facility D who did not report the ⁵⁷Co in PF-_Acc.

Precision:
All facilities have a Precision of the Bias, S_B, that is within the acceptable limit.

For further information, contact the NCRC at:

• tel: 613-954-6668 or 613-954-6667
• fax: 613-957-1089
• E-mail: Gary_H_Kramer@hc-sc.gc.ca
• WWW: Human Monitoring Laboratory
  http://www.hc-sc.gc.ca/hecs-sesc/ncrc