Patient dose in dual x-ray absorptiometry

Lewis, M.; Blake, Glen M.; Fogelman, Ignac

doi:10.1007/bf02352255

Cited by 153 publications

(62 citation statements)

References 10 publications

(11 reference statements)

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Section: Discussionmentioning

confidence: 99%

“…DXA values are also influenced by inhomogeneities in soft-tissue composition and fat distribution (9,10). The inability to account for growth-related variations in bone and body size and composition with this projection technique limits DXA bone determinations and leads to inaccurate measurements (7,(11)(12)(13)(14).In contrast, quantitative computed tomography (CT) and peripheral quantitative CT are not subject to these limitations because they provide a threedimensional assessment of bone structure. In addition, these techniques offer the ability to separate out trabecular bone, which is eight times more metabolically active than cortical bone (5,15-18), and provide a direct measure of volumetric bone density (19).…”

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confidence: 99%

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Quantitative CT Reference Values for Vertebral Trabecular Bone Density in Children and Young Adults

Gilsanz¹,

Pérez²,

Campbell³

et al. 2009

Radiology

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Purpose:To determine normative reference values for vertebral trabecular bone density (TBD) obtained by using quantitative computed tomography (CT) in healthy white children, teenagers, and young adults of both sexes. Materials and Methods:The data presented in this HIPAA-compliant study are a compilation of data from multiple investigations on the determinants of bone acquisition in healthy children conducted at this institution from 1992 to 2006. The institutional review board for clinical investigations approved the protocols for each of these studies, and written informed consent was provided by all parents and/or participants. Quantitative CT measurements of TBD (in milligrams per cubic centimeter) were obtained at the first, second, and third lumbar vertebrae in 1222 healthy white male and female subjects aged 5-21 years (mean age for male subjects, 15.1 years Ϯ 3.6 [standard deviation]; range, 5.6 -21.9 years; mean age for female subjects, 14.2 years Ϯ 3.9; range, 5.7-21.6 years; mean age for both sexes, 14.6 years Ϯ 3.8). Mean and standard deviations for TBD were determined for each age group in 1-year intervals, and Student t tests for unpaired data were performed to compare male subjects with female subjects. Results:TBD increased equally during growth in male and female subjects. Although the percentage increase in TBD was similar for both sexes (23.7% [57 of 241] for male subjects, 22.2% [54 of 243] for female subjects), the rise began and reached peak values at an earlier age in female subjects; increases in TBD occurred from 10 -15 years of age in female subjects, whereas in male subjects, these increases were not observed until age 12 years and were completed at 17 years. Conclusion:This study provides reference standards for quantitative CT bone measurements in children and young adults, which may aid in the diagnosis, prevention, and treatment of pediatric metabolic bone disorders. Note: This copy is for your personal, non-commercial use only. To order presentation-ready copies for distribution to your colleagues or clients, use the Radiology Reprints form at the end of this article.M easurements of bone density during childhood are commonly obtained to assess the deficiencies in bone accumulation associated with a multitude of pediatric disorders. Moreover, the amount of bone that is gained during growth is an important determinant of the risk for osteoporosis later in life (1,2), and available data suggest that the genetic susceptibility to osteoporosis is detectable in childhood (3). Peak bone mass, a major determinant of the future risk of fractures in the elderly, is largely achieved by the end of sexual development (4).Because of its availability, minimal radiation exposure, and relative ease of use, dual-energy x-ray absorptiometry (DXA) is the most commonly employed quantitative radiologic method to assess bone mass at any age (5). The interpretation of DXA bone studies is considerably more challenging in children than in adults. Although reference data and diagnostic algorithms are avai...

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Quantitative CT Reference Values for Vertebral Trabecular Bone Density in Children and Young Adults

Gilsanz¹,

Pérez²,

Campbell³

et al. 2009

Radiology

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“…The precision of the measurements is 1.0 and 2.0% for the FFM and FM, respectively (Mazess et al, 1990;Slosman et al, 1992). The effective total body radiation dose is 5.2 mSv (Blake et al, 1996;Lewis et al, 1994). Percentage of body fat was measured using the manufacturer's default de®ni-tion.…”

Section: Body Composition Measurementsmentioning

confidence: 99%

Age-related differences in fat-free mass, skeletal muscle, body cell mass and fat mass between 18 and 94 years

et al. 2001

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Objective: To determine (1) lean and fat body compartments, re¯ected by fat-free mass (FFM), appendicular skeletal muscle mass (ASMM), body cell mass (BCM), total body potassium (TBK), fat mass and percentage fat mass, and their differences between age groups in healthy, physically active subjects from 18 to 94 y of age; and (2) if the rate of decrease in any one of the parameters by age might be accelerated compared to others. Methods: A total of 433 healthy ambulatory Caucasians (253 men and 180 women) aged 18 ± 94 y were measured by dual-energy X-ray absorptiometry (DXA) and whole body scintillation counter (TBK counter) using a large sodium iodide crystal (203 mm diameter). Results: The ASMM change (716.4 and 712.3% in men and women, respectively) in b 75 y-old compared to 18 to 34-y-old subjects was greater than the FFM change (711.8 and 79.7% in men and women, respectively) and this suggests that skeletal muscle mass decrease in older subjects was proportionally greater than non-skeletal muscle mass. BCM (725.1 and 723.2% in men and women, respectively) and TBK differences were greater than the differences in FFM or ASMM suggesting altered composition of FFM in older subjects. Women had lower peak FFM, ASMM, BCM and TBK than men. Conclusions: The decline in FFM, ASMM, BCM and TBK is accelerated in men and women after 60 y of age and FFM, ASMM, BCM and TBK are signi®cantly lower than in younger subjects. Fat mass continued to increase until around 75 y. Sponsorship: Foundation Nutrition 2000Plus, Geneva, Switzerland. Descriptors: dual energy X-ray absorptiometry (DXA); total body potassium (TBK); fat-free mass; appendicular skeletal muscle mass (ASMM); body cell mass (BCM); fat mass.

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“…22,23 The effective total body radiation dose is 5.2 mSv. 24,25 The percentage of body fat was measured using the manufacturer's default definition.…”

Section: Anthropometric Measurements and Bioelectrical Impedance Analmentioning

confidence: 99%

Longitudinal follow-up of body composition in hematopoietic stem cell transplant patients

Kyle

Chalandon

Miralbell

et al. 2005

Bone Marrow Transplant

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Summary:Patients with hematological malignancies are well nourished prior to allogeneic hematopoietic stem cell transplantation (HSCT). HSCT and associated complications can affect body composition. The study evaluated crosssectionally the prevalence and longitudinally the changes in lean body mass index (LBMI) in HSCT patients. Patients (n ¼ 82) were classified as normal or low LBMI. Logistic regression analyses were used to estimate odds ratios (OR) for low vs normal LBMI, between healthy volunteers and patients; for limited or extensive vs no chronic graft-versus-host-disease (GVHD); and for decreased (Karnofsky o80) vs normal functional status (480). Patients were significantly more likely to have low LBMI at 6, 12 months, 2-3, 4-6 and 46 years than volunteers. In all, 38% of patients were below pre-HSCT LBMI at 4-6 years post-HSCT. Low LBMI was significantly associated with steroid treatment (OR 2.6, confidence intervals (CI) 1.3-5.2, P ¼ 0.008); limited (OR 5.5, CI 1.7-18.5, P ¼ 0.005) or extensive chronic GVHD (OR 20.3,, Po0.001); and decreased performance status (Karnofsky scores of p80) (OR 2.7, CI 1.3-5.9, P ¼ 0.01). Patients were more likely to have low LBMI than volunteers. Chronic GVHD and low performance status were associated with low LBMI; thus, complications and/or treatment increase the likelihood of low LBMI. Patients with hematological malignancies are usually well nourished at the time of allogeneic hematopoietic stem cell transplantation (HSCT). 1,2 However, nutritional consequences after HSCT have not been well studied. Underweight patients are at increased risk of death in the early post-HSCT period, and nonrelapse mortality is greater for extremely underweight or overweight patients. 3,4 High body mass index (BMI), weight normalized for height, may also affect treatment-related toxicity and mortality. 5 Furthermore, low lean body mass (LBM) has been associated with poor outcome and increased length of hospital stay. 6 Allogeneic HSCT and associated complications, including infections and graft-versus-host-disease (GVHD), can affect body weight and body composition. Immunosuppressive therapy after transplantation has been shown to alter skeletal muscle metabolism. 7 Corticosteroids promote muscle atrophy by increasing the rate of protein catabolism, amino-acid efflux, while simultaneously decreasing the rate of protein synthesis. 8 Thus, treatment and complications following HSCT exert profound negative effects on LBM.As low LBM is associated with poor outcome, the evaluation of LBM and body fat changes in pre-and post-HSCT patients can aid in adapting nutrition policy, for example, nutrition support in malnutrition and food restriction in obesity. 9 Just as BMI is useful in evaluating the excess or deficit in body weight in individuals of different heights, the lean body mass index (LBMI, kg/m 2 ) and body fat mass index (BFMI, kg/m 2 ) are potentially useful in evaluating body composition parameters by effectively eliminating differences in LBM and body fat with height. 10 Height-indepe...

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Patient dose in dual x-ray absorptiometry

Cited by 153 publications

References 10 publications

Quantitative CT Reference Values for Vertebral Trabecular Bone Density in Children and Young Adults

Quantitative CT Reference Values for Vertebral Trabecular Bone Density in Children and Young Adults

Age-related differences in fat-free mass, skeletal muscle, body cell mass and fat mass between 18 and 94 years

Longitudinal follow-up of body composition in hematopoietic stem cell transplant patients

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