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We describe a new method for assessing the Ca/P ratio of bone in vivo using gamma-ray photon absorptiometry. The theoretical approach of the method and the estimation of the variance are presented. Two radiation sources, Gd-153 (100 keV), and I-125 (27.5 keV), and a germanium detector were used to determine this ratio. Measurements were made on bone phantoms with different Ca/P ratios; also, the ratio was measured on lamb and sheep tibias, rabbit tibias, and human fingers. Since the accuracy of the method is affected by the amount of fat and collagen in the measurement field, the effect of collagen and fat on the measurements also was investigated. In all cases, the precision of the method, expressed as the coefficient of variation (CV): 100x standard deviation/mean, was near to the theoretical one, ranging from 1.8% to 3.2%. For human fingers, the CV was 3.2%, a value near to the theoretical 2.9% with a dose to the skin ranging from 0.044 to 0.066 mGy, depending on the width of the finger.

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BackgroundThe first positive patient with influenza A (H1N1) was recorded in March 2009 and the pandemic continued with new outbreaks throughout 2010. This study’s objective was to quantify the total cost of inpatient care and identify factors associated with the increased cost of the 2009–2010 influenza A pandemic in comparison with nonviral respiratory infection.MethodsIn total, 133 positive and 103 negative H1N1 patients were included from three tertiary care hospitals during the two waves of H1N1 in 2009 and 2010. The health costs for protective equipment and pharmaceuticals and hospitalization (medications, laboratory, and diagnostic tests) were compared between H1N1 positive and negative patients.ResultsThe objective of the study was to quantify the means of daily and total costs of inpatient care. Overall, cost was higher for H1N1 positive (€61,0117.72) than for H1N1-negative patients (€464,923.59). This was mainly due to the protection measures used and the prolonged hospitalization in intensive care units. In H1N1-negative patients, main contributors to cost included additional diagnostic tests due to concern regarding respiratory capacity and laboratory values, as well as additional radiologic and microbial culture tests. The mean duration of hospitalization was 841 days for H1N1 positive and 829 days for negative patients.ConclusionCost was higher in H1N1 patients, mainly due to the protection measures used and the increased duration of hospitalization in intensive care units. An automated system to monitor patients would be desirable to reduce cost in H1N1 influenza.

A single KVp quantitative CT (QCT) technique was used for measuring the spinal trabecular bone density. The trabecular bone equivalent density (TBED) was expressed as the density of a K2HPO4 solution that exhibits a linear attenuation coefficient identical to that of trabecular bone. A field non-uniformity correcting factor was obtained from experiments on phantoms. The effective equivalent dose of the whole examination (four sections and a scout view) is 370 muSv. The in vivo short-term precision (reproducibility coefficient of variation) ranges from 1.4% to 4.1% depending on the TBED values of the normal subjects. The TBED was measured in 206 normal Greeks aged 30-69 years. Average TBED decreased with increasing age for both sexes. Analysis considering separately each vertebra showed a tendency to a caudal spinal TBED reduction. No correlation was found between the TBED values and the body habitus, milk consumption, smoking habits in men, and number of full-term pregnancies. A significant difference (p less than 0.01) was found between the TBED values of the normals and those of 50 women suffering from post-menopausal osteoporosis, 37 alcoholic men, and 12 gastrectomized men (Billroth II). Quantitative CT has been established as a method of measuring TBED in health and disease, and the results from this study confirm these applications.