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PubMed1991

Bone mineral density and mass by total-body dual-photon absorptiometry in normal white and Asian men.

Total body bone mineral density, total body bone mineral mass (TBBM), and bone mineral densities (BMD) in seven different regions of the body were measured in 238 normal men (154 Whites and 84 Asians), age 22-94, using dual-photon absorptiometry. Although Asian men had lower TBBM and BMD in all regions (p less than 0.05) except the arms, when multiple regression was done with body weight, height, and age, no significant differences were found between Asians and Whites for bone measurements. Thus lower bone mineral densities and bone mineral mass in Asian males compared to White males appear to be due to differences in height and weight rather than to ethnic differences. The two groups were combined to derive multiple regression equations for TBBM, total-body BMD, and regional BMD. Age, weight, and height were significant in the multiple regression equations for TBBM, ribs BMD, and legs BMD. Age and weight, but not height, were significant for total-body BMD, trunk BMD, spine BMD, arm BMD, and pelvis BMD. Weight, but neither height nor age, was significant for head BMD. These reference normal bone mineral density and bone mineral mass standards are appropriate for both Asian and White males when adjusted for weight, height, and age.

Absorptiometry, Photon↗

PubMed1987

Photon absorptiometry.

Recently, there has been a renewed interest in the detection and treatment of osteoporosis. This paper is a review of the merits and limitations of the various noninvasive modalities currently available for the measurement of bone mineral density with special emphasis placed upon the nuclear medicine techniques of single-photon and dual-photon absorptiometry. The clinicians should come away with an understanding of the relative advantages and disadvantages of photon absorptiometry and its optimal clinical application.

Bone and Bones↗

PubMed1990

Adaptation of cancellous bone to aging and immobilization in the rat: a single photon absorptiometry and histomorphometry study.

Nine-month-old female rats were double-labeled with bone markers and subjected to right hindlimb immobilization or served as control for 0, 2, 10, 18, or 26 weeks. The right limb was immobilized against the abdomen, thus unloading it, while the left limb was overloaded during ambulation. Single photon absorptiometry and cancellous bone histomorphometry were performed on dissected intact femur and 20-microns-thick undecalcified specimens of the proximal tibial metaphysis. In the unloaded limb, immobilization-induced muscle and cancellous bone loss occurred rapidly before 10 weeks and stabilized at 50% less bone mass after 18 weeks. Unloading caused a negative bone balance from a combination of elevated bone resorption and depressed bone formation. At 2, 10, and 18 weeks of immobilization, the ratios of bone resorption to bone formation surfaces were 1.6, 1.5, and 1.3, respectively; at 26 weeks, the ratio was 1. The bone loss was accompanied by poorer trabecular architecture (trabecular number decreased and trabecular separation increased), reaching the maximum at 18 weeks and stabilizing thereafter. These observations are in general agreement with Frost's postulate for mechanical effects on lamellar bone remodeling, and the findings on disuse osteoporosis in man. Therefore, the one-legged immobilization model can be useful in studies of the mechanisms of structural adaptation to mechanical usage.

Absorptiometry, Photon↗

PubMed1977

[The use of photon absorptiometry in renal osteodystrophy (author's transl)].

In 58 patients with end-stage renal failure before commencement of regular hemodialyses treatment (RTD) and 58 patients under RTD bone mineral content (BMC) was determined by the use of the photon absorptiometry. Further the effect of a treatment with bitamin D3 and 5,6-trans-25-OH-vitamin D3 on BMC was studied. There existed a negative correlation between the duration of chronic renal failure or of RDT as well as of the serum parathyroid hormone level to BMC. No correlation was found between BMC and serum calcium level. During a 14 months-course treatment with vitamin D3 or 5,6-trans-25-OH-vitamin D3 BMC increased. The method of photon absorptiometry presented itself as an easy and well reproducible technique for routine examinations.

Adolescent↗

PubMedDate not supplied

Evaluation by dual-photon absorptiometry of bone mineral loss in rheumatic children on long-term treatment with corticosteroids.

The introduction of reliable and non-invasive methods of measuring bone mass has allowed investigators to study the bone mass loss (ostopenia) related to rheumatic diseases and corticosteroid therapy. Serial measurements of lumbar bone mineral density (BMD) by dual-photon absorptiometry (DPA) is an effective method of checking bone mineralisation. In children, however, the bone mass is not constant over time, so bone densitometric measurements must take into account not only the net loss but also the missing increase in BMD. In order to study the effects of both chronic rheumatic disease and the long-term administration of corticosteroids in children, as a first step the reference curves of bone mineralisation (mean BMD values and annual % BMD growth rates) were calculated from a control population of 79 children (32 males and 47 females) aged 3 to 20 years. All the subjects involved in the study underwent DPA utilising a Norland Bonestar instrument provided with a 153 Gadolinium source and the average BMD (g/cm2) of the lumbar spine was calculated. As a second step, a transverse study was carried out on a series of 157 children and young adults affected by chronic rheumatic diseases with juvenile onset. As a third step, a longitudinal study on the adverse effect of the chronic administration of corticosteroids on bone mineralisation was carried out on a series of 58 patients affected by chronic rheumatic diseases with juvenile onset who were being treated with long-term corticosteroids. Serial measurements of bone mass should help us to improve our strategies in preventing and counteracting osteopenia due to the chronic administration of corticosteroids also in children.

Absorptiometry, Photon↗

PubMed1992

Comparison of bone mineral content among Japanese, Koreans, and Taiwanese assessed by dual-photon absorptiometry.

Throughout the world the diagnosis and management of osteoporosis currently involves the measurement of bone mineral content. There are, however, no studies comparing bone mineral content among Asian people. This cross-sectional study was designed to quantify spine and femur bone mineral density (BMD) in Japanese and compare BMD among Asian people (Japanese, Koreans, and Taiwanese) using the same model dual-photon system (Norland Model 2600). Following a peak BMD in the third and fourth decades, the Japanese BMD values of the lumbar spine and femoral neck showed a clear decrease (annual loss of 0.99 and 0.74%, respectively) with age in females. On the other hand, Japanese BMD values were stable in males until the fifth decade. There was some decrease in BMD with age after the fifth decade, which was much less obvious than that in females. An age-dependent loss of BMD was clearly observed in Japanese and Korean but not in Taiwanese females. Korean males seemed to have a clearer age-dependent loss of BMD compared to Japanese males. Our findings indicate that differences may exist in the BMD of Asian people and that in addition to the quantitative determination of individual BMD, dual-photon absorptiometry may be useful for the comparison of BMD among different ethnic and cultural groups.

Absorptiometry, Photon↗

PubMed1992

Advantages of peripheral radiogrametry over dual-photon absorptiometry of the spine in the assessment of prevalence of osteoporotic vertebral fractures in women.

Since osteoporosis develops in most postmenopausal women and is probably the most important single factor in the pathogenesis of osteoporotic fractures of the spine, hip, and wrist (and at other sites), methods suitable for mass screening should be developed. In this study of 97 women aged 24-79, measurements of the lumbar spine mineral content by dual-photon absorptiometry (DPA) were compared with the summed combined cortical thickness measurements from radiographs of the radius and metacarpal II (MR). There was good correlation between the two methods (r = 0.90). The correlation of age with MR was higher than with DPA. The correlation of years postmenopause was significant with MR but not with DPA. Taking the -2 SD level of the premenopausal means to be previously established vertebral fracture thresholds, 24% of the DPA measurements, but no MR measurements in patients with vertebral compressions, were above the fracture threshold. Since MR measurement requires taking only two small plain radiographs using ordinary x-ray equipment, it is concluded that this less expensive method is better suited to screening for osteoporotic vertebral fracture risk in postmenopausal women than DPA.

Absorptiometry, Photon↗

PubMedDate not supplied

Bone mineral densitometry in dialyzed patients: quantitative computed tomography versus dual photon absorptiometry.

Reduced bone mineral density (BMD) increases risk of fractures, thus making it necessary to monitor patients suffering from chronic renal failure and consecutive disturbance of bone metabolism. In order to evaluate the reliability of available methods, bone mineral density of the lumbar spine assessed with single energy computed tomography (QCT) was compared with bone mineral density of the lumbar spine, femoral neck, Ward's triangle and trochanteric region measured by dual energy photon absorptiometry (DPA) in 45 hemodialyzed patients with a mean hemodialysis duration of 35 +/- 26 months (SD). Depending on the measurement site and method 4-34% of dialyzed patients suffered from reduced BMD (z-score < -2). The highest correlation (r = 0.61, p < 0.01) was found between QCT of the spine, trabecular bone, and DPA of Ward's triangle. One year after baseline measurement bone mineral density was reassessed after randomization to either QCT or DPA in 14 and 18 patients, respectively. Whereas lumbar spine and femoral neck did not change, mean BMD showed a decrease at the measurement sites of Ward's triangle (DPA), trochanteric region (DPA) and trabecular bone of the spine (QCT), which, however, was statistically not significant. Cortical BMD of the spine assessed with QCT showed an increase. Although there is some reduction in bone density at most sites in hemodialyzed patients, no significant bone loss could be demonstrated over the course of 1 year.

Absorptiometry, Photon↗

PubMed1985

Comparison of single- and dual-photon absorptiometry in postmenopausal bone mineral loss.

We describe a single photon absorptiometric (SPA) technique, which enables differential estimation of the rates of loss from trabecular and cortical bone. Ten scans are obtained in the forearm: six in an area with about 7% trabecular bone and four scans in the adjacent distal area with a trabecular bone content of 25%. By comparing bone masses of these two sites in 19 postmenopausal and 53 premenopausal women, the postmenopausal trabecular bone loss was estimated to be approximately seven times greater than cortical loss within the first years of cessation of regular vaginal bleeding. On a group basis the bone loss at the distal forearm scan site (by SPA) corresponded closely to the spinal bone loss (by dual-photon absorptiometry). The reproducibility of the two scan sites in the forearm was 1-1.5% (CV%), which makes the method suitable for longitudinal studies. Corrections for variations in fatty tissue covering can be made without deterioration of the reproducibility. The high precision can only be achieved with a good calibration procedure; if calibration is not done the reproducibility error increases two- or threefold.

Adult↗

PubMed1993

Body composition study in the elderly: comparison between tritium dilution method and dual photon absorptiometry.

BACKGROUND: The methods commonly employed in body composition study in elderly persons derive fat-free mass (FFM) by measures of total body water (TBW); these methods assume FFM hydration constant (TBW/FFM = 0.732). The aim of our study was to verify the accuracy of the TBW method in FFM estimation and to study the variability of fat-free mass hydration (TBW/FFM) in healthy elderly subjects. METHODS: We assessed FFM in 27 healthy old subjects (76 +/- 7 yrs) by dual photon absorptiometry (DPA) and by TBW measured by 3H2O. Furthermore, to verify the accuracy in FFM estimation by our methods, we measured resting metabolic rate (RMR) by indirect calorimetry. RESULTS: FFM hydration was 71.9 +/- 4.9 (range 63.6-80.4%), a range larger than that reported by direct chemical analysis in adults. The FFM hydration measured in our subjects was not different from the 73.2 value currently used in healthy adults. FFM values derived by TBW (assuming TBW/FFM = 0.732) were not significantly different from FFM measured by DPA. We correlated FFM with resting metabolic rate and found a similar correlation between RMR and FFM-DPA (r = .89, p < .001) and FFM-TBW (r = .85, p < .001). CONCLUSIONS: Both methods employed in our study have proved to be accurate in estimating FFM in elderly persons; particularly, the value of 0.732 assigned to FFM hydration to derive fat-free mass in adults can be employed also in body composition study of the elderly.

Absorptiometry, Photon↗

PubMed1992

A comparison of the bone mineral density of the vertebral bodies and the hip in elderly females with hip fractures. Assessment using dual photon absorptiometry.

The influence of decreasing bone mineral density with age and the occurrence of hip fractures in elderly females was investigated. Normal hips were studied in 287 healthy women whose ages ranged from 20 to 90 years old. The normal hip in 61 patients who had all suffered a femoral neck or intertrochanteric hip fracture, and were over 60 years old, were also studied and compared. The bone mineral density (BMD) of the lumbar vertebrae and the hip was measured with dual beam photon absorptiometry, for all patients. There was no correlation between the bone mineral density of the lumbar vertebral bodies, and the bone mineral density of the proximal femur. The peak bone mass in e lumbar vertebrae was seen in the thirties, but the peak bone mass in the hip was seen in the twenties. Bone mineral density in the lumbar vertebrae and in the hip was decreased in the patients who had sustained a hip fracture when compared to the control patients. The bone mineral density in the proximal femur was significantly reduced in patients who had sustained a hip fracture, especially in the region of Ward's triangle. These findings suggested that decreased bone mass in the hip at Ward's triangle may be correlated with the occurrence of hip fractures.

Absorptiometry, Photon↗

PubMed1990

[Bone mineral loss due to premenopausal oophorectomy assessed by dual photon absorptiometry].

Although it has been reported that bone mineral loss due to oophorectomy (OPX) occurs mainly in the axial bone, especially in the trabecular bone, there have been no reports on the use of this method for simultaneous total body calcium measurement. Furthermore, the occurrence of bone mineral loss in regional bone mineral density (BMD) after OPX has not been clarified. We investigated whether there is a decrease in regional BMD after OPX, and whether there are regional differences in bone mineral loss following OPX. The BMD was measured by dual photon absorptiometry in 21 premenopausal oophorectomized subjects (mean age: 46.8 +/- 4.0 yr, mean duration after OPX: 48.0 +/- 40.0 months) and 19 age- and body size-matched females. In OPX subjects, the spinal BMD was significantly lower (corresponding to 87.0 +/- 2.4% of control) than those of the cranium, arms and legs (92.1 +/- 2.6, 97.2 +/- 1.2, 95.4 +/- 1.6% respectively). Furthermore the oophorectomized subjects were divided into three groups according to duration after OPX as follows; within 1 (n = 7), 2-5 (n = 7) and over 6 years (n = 7). The spinal BMD had already tended to decrease in the within 1 year group and significantly decreased in the over-6-year group. On the other hand, there were no differences in the within 1 year group in arm and leg BMD compared with the control. However, in the over-6-year group they were significantly decreased. These results suggest that bone mineral loss in oophorectomized subjects occurs mainly in spinal bone, and the degree of bone mineral loss might be different in regional bone.

Absorptiometry, Photon↗

PubMed1992

[Bone risk of hormone-suppressing therapy in differentiated thyroid epithelioma. Study by dual photon absorptiometry].

A decreased bone mineral density is a well known complication of thyrotoxicosis. If bone is also adversely affected by a subclinical hyperthyroidism is still debated. Such a situation is deliberately induced for treatment of thyroid differentiated carcinoma. We compared bone mineral measurements in case of thyroid carcinoma exposed to prolonged suppressive hormonal treatment (288 patient year, LT3 in 87%) and in age and weight matched controls. We did not find any difference in both sexes between the two populations in term of fracture rate and vertebral mineral density measured by dual photon absorptiometry, nor any influence of gonadal status in women.

Absorptiometry, Photon↗

PubMed2006

Photon absorptiometry, bone densitometry and the challenge of osteoporosis.

During the lifetime of Physics in Medicine and Biology, osteoporosis has been recognized as the cause of a major health burden for societies, particularly within developed countries. The health detriment is associated with the consequences of bone fractures and the subsequent increases in morbidity and mortality. Much of the credit for the current availability of means for identifying groups of subjects at risk of fracture and the provision of means for the effective treatment of excessive bone loss can be attributed to the technique of dual photon absorptiometry. In this review, the history of the development of techniques based on the interactions of x- and gamma-rays with bone is considered and the ultimate dominance of x-ray based absorptiometry is described. The advantages and disadvantages of current absorptiometric techniques are presented and the likely future path for bone measurement is outlined.

Absorptiometry, Photon↗

PubMed1990

[Bone density after iatrogenic subclinical long-term thyrotoxicosis. Measurement by dual photon absorptiometry].

Thyrotoxicosis may be held responsible for osteoporosis. The question is whether a very slight subclinical hyperthyroidism, as is desirable in the post-operative treatment of differentiated thyroid carcinoma, can in the long run be detrimental to bone tissue. In a series of 37 patients, aged 50.9 +/- 11.1 years, presenting with the features of subclinical hyperthyroidism of 8.0 +/- 4.8 years duration, the authors have been unable to find any change in paraclinical parameters of bone and calcium-phosphate metabolism. Thirty-six of these 37 patients showed no abnormal decrease of vertebral bone density measured by dual photon absorptiometry.

Absorptiometry, Photon↗

PubMed1993

Bone mineral density in surgically postmenopausal women receiving hormonal replacement therapy as assessed by dual photon absorptiometry.

A total of 118 postmenopausal women who had undergone hysterectomy and bilateral oophorectomy were invited to participate in this study. Patients were randomly allocated to one of four study groups which received, respectively, conjugated equine oestrogens (CEE) 0.625 mg/day over a 25-day cycle each month (n = 28); transdermal 17 beta-oestradiol 50 micrograms/day over a 24-day cycle each month (n = 28), CEE 0.625 mg/day every day of the month (n = 32) and no treatment the control group (n = 30). All the treated patients also received 2.5 mg/day medroxyprogesterone acetate sequentially for the last 12 days of each cycle. Dual photon absorptiometry was performed before therapy commenced and repeated after 1 year in all four groups. The three therapeutic regimens induced increases in bone mass, whereas a significant decrease was observed in the control group (P < 0.05).

Absorptiometry, Photon↗

PubMed1992

Determination of bone mineral density by quantitative computed tomography and single photon absorptiometry in subclinical hyperthyroidism: a risk of early osteopaenia in post-menopausal women.

OBJECTIVE: There is evidence that treatment with L-thyroxine increases the risk of early osteopaenia. The aim of our study was to investigate the effect of subclinical hyperthyroidism in patients on TSH-suppressive L-thyroxine in view of the increased risk of decalcification. DESIGN: Measurements of bone mineral density were performed in patients with subclinical hyperthyroidism at different scanning sites of varying trabecular portion. Bone mineral values as well as biochemical data were compared to those of normal controls. PATIENTS: Fifty patients (nine men, 25 premenopausal and 16 post-menopausal women) on TSH-suppressive doses of L-thyroxine were investigated after removal of thyroid cancer. MEASUREMENTS: Dual energy quantitative computed tomography was used for osteodensitometry in the lumbar spine. Single photon absorptiometry from a 125I source was applied to the calcaneus, midshaft radius and distal as well as proximal scanning sites of the distal radius. Normal bone mineral values for each measurement site were taken from healthy reference populations. RESULTS: A significant decrease of bone mineral density in the calcaneus was found in 26 of 50 patients. Bone mass assessment yielded a 9.1% decrease of mean bone mineral content in all patients compared to controls (P less than 0.01). The decrease in post-menopausal women was 22% (P less than 0.001). In premenopausal women bone mineral density changes in the calcaneus were not statistically significant. Cortical measurement sites like the midshaft radius and the proximal scanning site of the distal forearm showed a 14.8% (P less than 0.05) and 10.8% (P = NS) decalcification in post-menopausal women but normal values at the distal scanning site. The lumbar spine was not affected by subclinical hyperthyroidism in either pre or post-menopausal women. In hypoparathyroid patients, bone density did not essentially differ from normals. There was no significant correlation between bone mineral values and duration of treatment or osteocalcin values. CONCLUSIONS: Our data suggest that TSH suppressive L-thyroxine treatment has a detrimental effect on the appendicular skeleton in post-menopausal women. Additional effects of oestrogen deficiency and subclinical hyperthyroidism might lead to accelerated bone loss requiring close supervision to determine the smallest dose needed for suppression of the pituitary-thyroid axis.

Absorptiometry, Photon↗

PubMed1989

Identification of women at risk for developing postmenopausal osteoporosis with vertebral fractures: role of history and single photon absorptiometry.

Putative risk factors for the development of postmenopausal osteoporosis (PMO) with vertebral fractures were examined in a retrospective study of 663 postmenopausal white females aged 45-75 years (266 women with non-traumatic vertebral compression fractures (VF+), 134 non-fractured women from a general medicine clinic (controls) and 263 non-fractured women who were evaluated when they presented specifically for osteoporosis screening (VF-]. The VF+ women differed from control women in several respects. The VF+ group reported a higher prevalence of a positive family history of osteoporosis, and a higher prevalence of a history of medical or surgical conditions known to be independently associated with metabolic bone disease, had fewer children, were smaller (weight, height) and were slightly older. The two groups, VF+ and controls, did not differ with respect to cigarette smoking, alcohol consumption, exercise habits, menstrual or menopausal history, dietary intake of milk and cheese or in amount taking calcium supplements during pregnancy. The VF+ group also differed in certain respects from the VF- group. The VF+ group were smaller (weight, height) and were older. The VF+ group had lower cortical bone mass (measured by single photon absorptiometry of the non-dominant forearm) than either the control or VF- groups. The latter two groups did not differ from each other with respect to this measurement. These markers demonstrated limited sensitivity and specificity as estimated from a confirmatory data set, particularly for the historical and anthropometric variables. We conclude that an assessment of the risk of developing PMO with vertebral fractures cannot be based on the putative risk factors as measured in our study, but must be based on measurement of bone mass.

Absorptiometry, Photon↗