• Imaging Science in Dentistry
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• v.47 no.4
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• pp.247-254
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• 2017

Purpose: Dual-energy X-ray imaging is widely used today in various areas of medicine and in other applications. However, no similar technique exists for dental applications. In this study, we propose a dual-energy technique for dental diagnoses based on voltage-switching. Materials and Methods: The method presented in this study allowed different groups of materials to be classified based on atomic number, thereby enabling two-dimensional images to be colorized. Computer simulations showed the feasibility of this approach. Using a number of different samples with typical biologic and synthetic dental materials, the technique was applied to radiographs acquired with a commercially available dental X-ray unit. Results: This technique provided a novel visual representation of the intraoral environment in three colors, and is of diagnostic value when compared to state-of-the-art grayscale images, since the oral cavity often contains multiple permanent foreign materials. Conclusion: This work developed a technique for two-dimensional dual-energy imaging in the context of dental applications and showed its feasibility with a commercial dental X-ray unit in simulation and experimental studies.

• Proceedings of the Korean Society of Radiological Science
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• 1992.10a
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• pp.118.1-118.1
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• 1992

• The Journal of Korean Physical Therapy
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• v.15 no.4
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• pp.466-478
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• 2003

This study was to evaluate the body composition and bone mineral density according to aging in adult and investigated the relationship between various parameters such as body mass index(BMI), bone mineral density(BMD), bone mineral content(BMC), lean body mass(LBM), fat mass(FM) and the value obtained from dual energy X-ray absorptiometry(DEXA). The subjects were composed of healthy adult male and female who were $20^{\sim}73$ years old and they were divided three group according to age (A group : 20-39 yrs., B group : 40-59 yrs., C group : more than 60 yrs.). The conclusion derived from statistical analysis was as follows : 1. Bone mineral content and density were significantly affected by lean body mass(relatively, R=0.85 - 0.63). 2. There was significant difference among age groups in total bone mineral density. 3. There was significant difference among age groups in bone mineral content of male and female. 4. Lean body mass is diminished according to age, but there was not significant difference among age groups. 5. Fat mass of A group in male had the highest mass and followed by C group and B group. In female groups, fat mass of A group had the highest mass and followed by B group and C group. Abdominal fat mass is increased according to age. This result suggest that aging was closely relation with loss of muscle mass, bone mineral density and bone mineral content.

• Journal of Radiation Industry
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• v.12 no.4
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• pp.317-324
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• 2018

The results of bone mineral density analysis using DXA were compared between automatic and manual methods. The purpose of this paper is to verify the range of errors of each analysis method in the same patient and select a proper method to minimize errors. Comparisons between automatic and manual analysis methods were made using BMD, BMC and AREA. Basal and follow up examinations were performed with the patients of normal, osteopenia and osteoporosis. In the basal examinations, the precision errors between automatic and manual method showed 1.9% in normal, 3.1% in osteopenia and 3.8% in osteoporosis. In case of follow up studies, the precision errors between automatic and manual method showed 2.3% in normal, 3.2% in osteopenia and 3.5% in osteoporosis. BMC and AREA also showed a tendency to increase precision errors on osteopenia and osteoporosis. Therefore, a manual method would be a better option to minimize errors in patients with osteopenia and osteoporosis.

• Journal of Radiation Industry
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• v.11 no.1
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• pp.27-31
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• 2017

Reliable follow-up of bone mineral density (BMD) by dual energy X-ray absorptiometry (DXA) is essential in clinical practice. When there is a difference in the BMD values from DXA systems in the same patient, cross calibration equation is required for the reliable follow-up. Unfortunately, no equation is existed in BMD measure between GE Lunar Prodigy Advance (US, GE Healthcare; LPA) and Osteosys Dexxum T (Korea, Osteosys; ODT) DXA systems. In this study, we evaluate the agreement of BMD values between LPA and ODT and suggest the cross calibration equation using European spine phantom (ESP) with two systems. We performed BMD measurements using ten scans with ESP in each DXA systems. We compared BMD values and calculated cross calibration equation by linear regression analysis. The comparison between the LPA and ODT bone densitometers used the ESP. Compared to the ESP BMD values, ODT underestimated 14.36% and LPA overestimated 12.96%. The average of total BMD measurement values acquired with ODT were 21.44% lower than those from LPA. Cross-calibration equation for LPA and ODT was derived from ESP. We calculated simple cross calibration equation for LPA and ODT DXA systems. Cross-calibration equation is necessary for the reliable follow-up of BMD values in two different systems.

• Journal of Korea Multimedia Society
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• v.12 no.9
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• pp.1233-1241
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• 2009

Over the 50 percents of women who are older than 45 years have osteoporosis. Because people hardly recognize this disease by themselves, the researches that measure bone mineral density have been doing widely to detect osteoporosis in the early stage. The most widely used methods for bone mineral density measurement are based on the X-ray imaging. Among them, DEXA(Dual-energy X-ray Absorptiometry) imaging is one of the important methods in bone mineral density measurement. DEXA images are useful methods to increase diagnosis efficiency by reducing anatomic noise as two images obtained from two different energy levels. However, it has some problems to a calibration parameter determined by the heuristic method for bone extraction. In this paper, we propose the method to extract bone in DEXA image using calibration parameter based on anatomic attenuation coefficient. The experimental results reveal that the proposed method is effective.

• The Korean Journal of Nuclear Medicine
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• v.38 no.4
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• pp.275-281
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• 2004

Compared with the earlier technique of dual photon absorptiometry (DPA) using $^{153}Gd$ radionuclide source, dual energy X-ray absorptiometry (DXA) has advantages of higher precision, accuracy and shorter scanning time. Despite the change from DPA to DPX, the nuclear medicine physicians has remained one of major suplier of this service due to long-standing use of DPA. Among many kinds of bone densitometries, DXA is the "gold standard" for the noninvasive diagnosis of osteoporosis. Especially there is no role for peripheral devices in the monitoring of patients on therapy. But, there are some areas of controversy related to the application of DXA, such as proper site of measurement, accurate interpritation, appropriate use of T-score, and the reference population young database. And the accuracy, precision, and quality control issues relating to bone density measurement are important subjects. To address these issues, the International Society for Clinical Densitometry (ISCD) has convened two Position Development Conferences and addressed official positions. This review deals the key elements of ISCD position paper and other important issues on the management of bone densitometry.

• Journal of radiological science and technology
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• v.25 no.1
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• pp.49-53
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• 2002

The femoral fracture is the most serious problem of old ages haying osteoporotic fractures. First of all, prevention to reduce the incidence of hip fracture and to identify the risk factor is essential subject. The purpose of this study is to investigate which geometric parameters of proximal femur are related to the hip fracture risk in old ages. Author analyzed the bone density and bone content of over 60 years old women who had suffered hip fracture (n=60) and non fracture groups (n=60). Author concluded that geometric measurements of proximal femoral part made on dual energy x-ray absorptiometry can predict hip fracture independently of bone mineral density.

• Hip & pelvis
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• v.30 no.4
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• pp.233-240
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• 2018

Purpose: This study aimed to evaluate the efficacy of simultaneous computed tomography (CT) and quantitative CT (QCT) in patients with osteoporotic hip fracture (OHF) by analyzing the osteoporosis detection rate and physician prescription rate in comparison with those of conventional dual-energy X-ray absorptiometry (DXA). Materials and Methods: This study included consecutive patients older than 65 years who underwent internal fixation or hip arthroplasty for OHF between February and May 2015. The patients were assigned to either the QCT (47 patients) or DXA group (51 patients). The patients in the QCT group underwent QCT with hip CT, whereas those in the DXA group underwent DXA after surgery, before discharge, or in the outpatient clinic. In both groups, the patients received osteoporosis medication according to their QCT or DXA results. The osteoporosis evaluation rate and prescription rate were determined at discharge, postoperative (PO) day 2, PO day 6, and PO week 12 during an outpatient clinic visit. Results: The osteoporosis evaluation rate at PO week 12 was 70.6% (36 of 51 patients) in the DXA group and 100% in the QCT group (P<0.01). The prescription rates of osteoporosis medication at discharge were 70.2% and 29.4% (P<0.001) and the cumulative prescription rates at PO week 12 were 87.2% and 60.8% (P=0.003) in the QCT and DXA groups, respectively. Conclusion: Simultaneous CT and QCT significantly increased the evaluation and prescription rates in patients with OHF and may enable appropriate and consistent prescription of osteoporosis medication, which may eventually lead to patients' medication compliance.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.25 no.6
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• pp.473-480
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• 2022

Purpose: Low bone mineral density (BMD) is a complication in children with inflammatory bowel disease (IBD). There are limited data evaluating dual-energy x-ray absorptiometry (DXA) as a screening tool for low BMD in children with IBD. We performed a single site retrospective analysis of DXA use. Methods: Children aged 5-18 years with IBD diagnosed between 2013 to 2017 at the Royal Children's Hospital, Australia, were included. Patient demographics, measures of disease activity, DXA scores, and factors related to BMD were collected. Results: Over a median follow up of 5.1 (4-6.4) years, 72/239 (30.1%) children underwent DXA, and 28/239 (11.7%) children had a second DXA. Our DXA practice differed to consensus guidelines regarding initial screening based on height and/or body mass index (BMI) z-score (8/17 [47.1%]), and repeat surveillance (13/42 [31.0%]). Children had a median lumbar spine (LS) z-score -0.80 (-1.65-0.075). Children with LS z-score≤-2.0 (n=14) had lower weight (6.57 [1.78-23.7] vs. 51.1 [26.5-68.7], p=0.0002) and height centiles (3.62 [1.17-17.1] vs. 42 [16.9-67.1], p=0.0001), and higher faecal calprotectin (FCP) (3041 [1182-4192] vs. 585 [139-2419], p=0.009) compared to children with LS z-score>-2.0. No fractures were reported. Of 28 children who underwent a second DXA 1.6 (1.1-2.2) years following initial DXA, no significant change in z-scores occurred. Conclusion: Children with IBD had low BMD. In addition to height centile and weight centile, FCP was associated with lower BMD, and should be considered in DXA screening guidelines. Greater clinician awareness of DXA consensus guidelines is required. Future prospective studies are required.