Abstract
We assessed the reproducibility of X-ray fluorescence-based lead measurements from multiple measurements made on a low-concentration plaster of paris phantom and in five subjects measured five times on two occasions. Over a 6-month period, 220 measurements of the same phantom were obtained and showed a standard deviation of 1.29 micrograms Pb (g plaster of paris)-1. The two sets of in vivo measurements were made 10 months apart and revealed a mean standard deviation of 3.4 micrograms Pb (g bone mineral)-1 and 5.1 micrograms Pb (g bone mineral)-1 for males and females, respectively. Our measured standard deviation exceeded by 20-30% the calculated standard deviation associated with a single measurement both in the phantom and in subjects. This indicates that some variance is introduced during the measurement process. Operator learning and consistency significantly minimized this increased variability. Measured lead concentrations of the left and right tibia in 14 subjects showed no significant differences between legs. As a result, either tibia can be sampled and compared over time. The levels of reproducibility we report here mean that X-ray fluorescence-based determinations of bone lead concentrations are reliable both over the short and long term. Thus, reasonably sized confidence intervals can be placed on detected changes in concentration and should permit acquisition of longitudinal data within a reasonable length of time.
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- Armstrong R., Chettle D. R., Scott M. C., Somervaille L. J., Pendlington M. Repeated measurements of tibia lead concentrations by in vivo x ray fluorescence in occupational exposure. Br J Ind Med. 1992 Jan;49(1):14–16. doi: 10.1136/oem.49.1.14. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Christoffersson J. O., Schütz A., Ahlgren L., Haeger-Aronsen B., Mattsson S., Skerfving S. Lead in finger-bone analysed in vivo in active and retired lead workers. Am J Ind Med. 1984;6(6):447–457. doi: 10.1002/ajim.4700060608. [DOI] [PubMed] [Google Scholar]
- Erkkilä J., Armstrong R., Riihimäki V., Chettle D. R., Paakkari A., Scott M., Somervaille L., Starck J., Kock B., Aitio A. In vivo measurements of lead in bone at four anatomical sites: long term occupational and consequent endogenous exposure. Br J Ind Med. 1992 Sep;49(9):631–644. doi: 10.1136/oem.49.9.631. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gordon C. L., Chettle D. R., Webber C. E. An improved instrument for the in vivo detection of lead in bone. Br J Ind Med. 1993 Jul;50(7):637–641. doi: 10.1136/oem.50.7.637. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hu H., Milder F. L., Burger D. E. X-ray fluorescence measurements of lead burden in subjects with low-level community lead exposure. Arch Environ Health. 1990 Nov-Dec;45(6):335–341. doi: 10.1080/00039896.1990.10118752. [DOI] [PubMed] [Google Scholar]
- Landrigan P. J. Toxicity of lead at low dose. Br J Ind Med. 1989 Sep;46(9):593–596. doi: 10.1136/oem.46.9.593. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Price J., Grudzinski A. W., Craswell P. W., Thomas B. J. Repeated bone lead levels in Queensland, Australia--previously a high lead environment. Arch Environ Health. 1992 Jul-Aug;47(4):256–262. doi: 10.1080/00039896.1992.9938358. [DOI] [PubMed] [Google Scholar]
- Silbergeld E. K., Schwartz J., Mahaffey K. Lead and osteoporosis: mobilization of lead from bone in postmenopausal women. Environ Res. 1988 Oct;47(1):79–94. doi: 10.1016/s0013-9351(88)80023-9. [DOI] [PubMed] [Google Scholar]
- Somervaille L. J., Chettle D. R., Scott M. C. In vivo measurement of lead in bone using x-ray fluorescence. Phys Med Biol. 1985 Sep;30(9):929–943. doi: 10.1088/0031-9155/30/9/005. [DOI] [PubMed] [Google Scholar]
- Somervaille L. J., Chettle D. R., Scott M. C., Tennant D. R., McKiernan M. J., Skilbeck A., Trethowan W. N. In vivo tibia lead measurements as an index of cumulative exposure in occupationally exposed subjects. Br J Ind Med. 1988 Mar;45(3):174–181. doi: 10.1136/oem.45.3.174. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Somervaille L. J., Nilsson U., Chettle D. R., Tell I., Scott M. C., Schütz A., Mattsson S., Skerfving S. In vivo measurements of bone lead--a comparison of two x-ray fluorescence techniques used at three different bone sites. Phys Med Biol. 1989 Dec;34(12):1833–1845. doi: 10.1088/0031-9155/34/12/007. [DOI] [PubMed] [Google Scholar]
- Todd A. C., McNeill F. E., Palethorpe J. E., Peach D. E., Chettle D. R., Tobin M. J., Strosko S. J., Rosen J. C. In vivo X-ray fluorescence of lead in bone using K X-ray excitation with 109Cd sources: radiation dosimetry studies. Environ Res. 1992 Apr;57(2):117–132. doi: 10.1016/s0013-9351(05)80073-8. [DOI] [PubMed] [Google Scholar]
- Wittmers L. E., Jr, Aufderheide A. C., Wallgren J., Rapp G., Jr, Alich A. Lead in bone. IV. Distribution of lead in the human skeleton. Arch Environ Health. 1988 Nov-Dec;43(6):381–391. doi: 10.1080/00039896.1988.9935855. [DOI] [PubMed] [Google Scholar]