53 REFERENCES S ly) = oO ao a CALCULATED HOT SPOT FROM @LOOD SPEC. ACT. omnes MEASURED HOT SPOTS T x F POP TTTTCOTTT 100 FoNN S048 o i a ~ heer 126-137, (1961). a UNIFORM LABEL ot; E E o ° DIFFUSE MEASURED - 0.01 oO. I | 10 5. Marshall, J. H. Measurements and Models of Skeletal Metabolism. Mineral Metabolism, Ed. C. Comar and F. Bronner, in press. 6. Lloyd, E. Quantitative Autoradiography of Ca‘5 in Bone. Calcified Tissues (University of Liege) 31, 381-390 (1965). ~y a 1. Evans, R. D. Radium and Mesothorium Poisoning and Dosimetry and Instrumentation Techniques in Applied Radioactivity. MIT Annual Progress Report MIT-952-2 (May 1965). 2. Fletcher, W., Loutit, J. F., and Papworth, D. G. Interpretation of Levels of Strontium-90 in Human Bone. Brit, Med. Journal 2, 1225-1230 (November 1966). 3. Sears, K. A., Jee, W.S.S., and Mays, C. W. Radium Dosimitry, University of Utah, College of Medicine, Department of Anatomy, Radiobiology Division, Semiannual Report, COO-226 (1962). 4. Rowland, R. E. Microseopic Metabolism of Ra?** in Canine Bone and its Bearing on the Radiation Dosimetry of Internally Deposited Alkaline Earths. Radiat. Res. 16 (1), | 100 YEARS Ra@?5 caRRIED Fig. 47-——Summaryof data on “Ra in human bone . Rowland, R. E. Unpublished data (1969). 8. Rowland, R. E. and Marshall, J. H. Radium in Human Bone: The Dose in Microscopic Volumes of Bone. Radiat. Res. 11, 299-313 (1959). 9, Ellsasser, J. C., Farnham, J. E., and Marshall, J. H. Comparative Kinetics and Autoradiography of Ca‘® and Bals3 in Ten-Year-Old Beagle Dogs; The Diffuse Component Distribution throughout the Skeleton. To be published VARIATIONS IN THE SURFACE AREA AND VOLUME OF BONE IN CROSS SECTIONS | TAKEN FROM A SINGLE HUMANRIB Elizabeth Lloyd The human rib is a convenient site for bone biopsy and is often used to obtain estimates of skeletal mineralization or , Tadioisotope uptake. It is not generally appreciated how much the character of a rib varies along its length. An automatic filin scanning system (CHLOE) is used to demonstrate the changes in surface-to-volume ratio which onefinds in a single human rib. Our interest in the surface area and volumeof cross sections of bone was aroused by the fact that some \otspot of loss | ress in , in the | atio to ; other, : level would Fic. 48.—Microradiographs of cross sections of the sixth rib