Abstract
Technetium-labelled ethane hydroxydiphosphonate (99mTc-EHDP) is a commonly used bone-scanning agent. After injection it leaves the circulation to enter bone and to be cleared by the kidney. The transcapillary exchange of 99mTc-EHDP in bone was examined and found to be low. The capillary movement was compared with that of sucrose, a freely diffusible substance, and it was found that the permeability ratio of 99mTc-EHDP to 14C-sucrose was similar to the diffusion coefficient ratio, suggesting that 99mTc-EHDP passes through the capillaries by the process of passive diffusion. The renal clearance of 99mTc-EHDP was 24 ml/min and was unaffected by the action of parathyroid hormone. After a fracture the bone blood flow increases, although the transcapillary extraction of 99mTc-EHDP does not change. This is because there is an increase, from recruitment and dilatation of capillaries, in the surface area available for exchange. Therefore the increased isotopic activity seen on a bone scan after a fracture is primarily related to an increase in bone blood supply from capillary enhancement within the cortex.
Full text
PDF
Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Brookes M., Richards D. J., Singh M. Vascular sequelae of experimental osteotomy. Angiology. 1970 Jun;21(6):355–367. doi: 10.1177/000331977002100601. [DOI] [PubMed] [Google Scholar]
- CRONE C. THE PERMEABILITY OF CAPILLARIES IN VARIOUS ORGANS AS DETERMINED BY USE OF THE 'INDICATOR DIFFUSION' METHOD. Acta Physiol Scand. 1963 Aug;58:292–305. doi: 10.1111/j.1748-1716.1963.tb02652.x. [DOI] [PubMed] [Google Scholar]
- Cofield R. H., Bassingthwaighte J. B., Kelly P. J. Strontium-85 extraction during transcapillary passage in tibial bone. J Appl Physiol. 1975 Oct;39(4):596–602. doi: 10.1152/jappl.1975.39.4.596. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Davies D. R., Bassingthwaighte J. B., Kelly P. J. Transcapillary exchange of strontium and sucrose in canine tibia. J Appl Physiol. 1976 Jan;40(1):17–22. doi: 10.1152/jappl.1976.40.1.17. [DOI] [PubMed] [Google Scholar]
- Galasko C. S. Skeletal metastases and mammary cancer. Ann R Coll Surg Engl. 1972 Jan;50(1):3–28. [PMC free article] [PubMed] [Google Scholar]
- Paradis G. R., Kelly P. J. Blood flow and mineral deposition in canine tibial fractures. J Bone Joint Surg Am. 1975 Mar;57(2):220–226. [PubMed] [Google Scholar]
- RENKIN E. M. Transport of potassium-42 from blood to tissue in isolated mammalian skeletal muscles. Am J Physiol. 1959 Dec;197:1205–1210. doi: 10.1152/ajplegacy.1959.197.6.1205. [DOI] [PubMed] [Google Scholar]