The first Densitometry installed in the Nuclear Medicine Department, NTUH dated July 1987, was Dual-Photon Absorptiometry (DPA). Since dual-energy was available, the whole body composition analysis measured three compartments: Bone mineral content (BMC), Lean mass (Fat-free) and Fat mass (Adipose tissue), and account for the body weight. However, normative database was not available for clinical diagnosis of osteoporosis, sarcopenia and obesity. Despite the clinical relevance of sarcopenia is widely recognized, there is currently no universally accepted definition of the disorder. The origins of sarcopenia are multi-factorial and correlates include muscle disuse, endocrine dysfunction, chronic disease, inflammation and nutritional deficiencies.
　　Early attempts to define sarcopenia were based on measurements of skeletal muscle mass with DXA in relation to body size. Calculated as the appendicular fat-free mass of the upper and lower limbs divided by body height squared, a patient’s muscle mass index indicated sarcopenia if it was >2 standard deviations (SD) below the sex-specific average in healthy young men or women. With this definition, the prevalence of sarcopenia was 53% in men and 43% in women over the age of 80 years. The diagnostic criterion was later refined to be appendicular fat-free mass adjusted for height and body fat mass, which provided a stronger association with functional performance using the same thresholds.
　　Most recently, an International Working Group on Sarcopenia presented four recommendations for identifying sarcopenia in clinical practice: (a) Assess patient for reduced physical capability (or weakness); (b) Consider sarcopenia in patients who are non-ambulatory or who cannot rise from a chair unassisted; (c) Assess usual walking pace (habitual gait speed) over a 4-m course; (d) Patients with a habitual gait speed <1.0 m/s should be considered for quantitative measurement of body composition by DXA.
　　Based on current evidence, none of the four potential outcomes in question is sufficiently comprehensive to recommend as a uniform single outcome in randomised clinical trials. Consequently, we propose sarcopenia may be optimally defined using a combination of measures of muscle mass and physical performance. Consequently, an unique One-stop service for the diagnosis of Sarcopenia in Radiology Department, which is only available in Taiwan since 2006. We used the diagnostic criteria of Asian Working Group of Sarcopenia (AWGS). We anticipate to provide the best Sarcopenia diagnosis for the elderly of the aged Taiwanese population, and set an example globally.