Advantage of 3D volumetric dosemeter in delivery quality assurance of dynamic arc therapy: comparison of pencil beam and Monte Carlo calculations.

OBJECTIVE: To evaluate the accuracy of pencil beam calculation (PBC) and Monte Carlo calculation (MCC) for dynamic arc therapy (DAT) in a cylindrically shaped homogenous phantom, by comparing the two plans with an ion chamber, a film and a three-dimensional (3D) volumetric dosemeter. METHODS: For this study, an in-house phantom was constructed, and the PBC and MCC plans for DAT were performed using iPlan® RT (BrainLAB®, Heimstetten, Germany). The A16 micro ion chamber (Standard Imaging, Middleton, WI), Gafchromic® EBT2 film (International Specialty Products, Wayne, NJ) and ArcCHECK™ (Sun Nuclear, Melbourne, FL) were used for measurements. For comparison with each plan, two-dimensional (2D) and 3D gamma analyses were performed using 3%/3 mm and 2%/2 mm criteria. RESULTS: The difference between the PBC and MCC plans using 2D and 3D gamma analyses was found to be 7.85% and 28.8%, respectively. The ion chamber and 2D dose distribution measurements did not exhibit this difference revealed by the comparison between the PBC and MCC plans. However, the 3D assessment showed a significant difference between the PBC and MCC (62.7% for PBC vs 93.4% for MCC, p = 0.034). CONCLUSION: Evaluation using a 3D volumetric dosemeter can be clinically useful for delivery quality assurance (QA), and the MCC should be used to achieve the most reliable dose calculation for DAT. ADVANCES IN KNOWLEDGE: (1) The DAT plan calculated using the PBC has a limitation in the calculation methods, and a 3D volumetric dosemeter was found to be an adequate tool for delivery QA of DAT. (2) The MCC was superior to PBC in terms of the accuracy in dose calculation for DAT even in the homogenous condition.

Chronic obstructive lung disease-related health care utilisation in Korean adults with obstructive lung disease.

OBJECTIVES: The numbers of nationwide epidemiological surveys about chronic obstructive pulmonary disease (COPD) prevalence and prospective cohort studies for health care utilisation are limited. We investigated COPD-related health care utilisation in adults with obstructive lung disease in the second Korean National Health and Nutritional Survey (KNHANES II) in 2001 using Korean national medical insurance claim data. METHODS: Among people aged >40 years, obstructive lung disease (OLD) is defined according to Global Initiative for Chronic Obstructive Lung Disease criteria. Data from a total of 1942 subjects were linked with Korean national medical insurance claims data, and we investigated their COPD-related out-patient visits from 2002 to 2005. RESULTS: Among the 1942 subjects, 256 (13.2%) had airflow obstruction. COPD-related out-patient visits were reported for 8.2% of patients without airway obstruction, 18.1% of those with mild airway obstruction, and 33.9% of those with moderate to very severe airway obstruction. Multivariate analysis revealed that previous COPD diagnosis by a physician (OR 2.54; P = 0.02) and lower socio-economic status (OR 0.45; P = 0.02) were independent predictors of COPD-related out-patient visits in subjects with OLD. CONCLUSIONS: Of the subjects with airway obstruction, those with poor financial status utilised COPD-related health care services less frequently, and those previously diagnosed as having COPD by a physician utilised the services more frequently.

The effects of total energy expenditure from all levels of physical activity vs. physical activity energy expenditure from moderate-to-vigorous activity on visceral fat and insulin sensitivity in obese Type 2 diabetic women.

AIMS: We examined the effects of physical activity with or without dietary restriction for 3 months on regional fat and insulin sensitivity and compared the effect of total energy expenditure from all levels of physical activity with that of physical activity energy expenditure from moderate-to-vigorous exercise in obese women with Type 2 diabetes. METHODS: In this randomized, controlled trial, we assessed change of body weight, abdominal visceral fat area, subcutaneous fat area and insulin sensitivity, expressed as K(ITT), and monitored total energy expenditure and physical activity energy expenditure using an accelerometer during a 12-week intervention in four groups: control, diet, exercise and diet plus exercise. RESULTS: The mean body mass index was 28.0 +/- 2.7 kg/m(2) and the mean duration of diabetes was 8 +/- 6 years. Both the diet and diet plus exercise groups showed significant body weight loss compared with the control group (P < 0.05). However, the visceral fat area was reduced only in the diet and exercise group (P = 0.017) and the subcutaneous fat area was reduced only in the diet group (P = 0.009). Mean energy intake was an independent determinant of the change in subcutaneous fat area (P = 0.020) and mean total anergy expenditure was an independent determinant of visceral fat area (P = 0.002). Insulin sensitivity K(ITT) was associated with physical activity energy expenditure (P = 0.006), energy intake (P = 0.047) and the change in fructosamine level (P = 0.016) but not with changes in body weight, subcutaneous fat area, visceral fat area or adipokine level. CONCLUSIONS: Exercise had an additive effect to dietary restriction on visceral fat reduction. Visceral fat area was associated with total energy expenditure, but insulin sensitivity was associated with physical activity energy expenditure.

Direct assessment of international consistency of standards for ground-level ozone: strategy and implementation toward metrological traceability network in Asia.

An international exercise to directly assess consistency of standards for ground-level ozone in East Asia was conducted as part of the East Asian Regional Experiment 2005 (EAREX 2005) in the framework of the Atmospheric Brown Clouds (ABC) project. Ten organizations collaboratively participated in the intercomparison. Four groups representing Japan, Korea, Hong Kong, and Taiwan made comparisons at the Gosan super observatory, Jeju Island, Korea, in March 2005, with ozone instruments calibrated to their national standards, and four Japanese groups made off-site comparisons with laboratory-level standards. All comparisons generally indicated good agreement with the standard reference photometer (SRP) 35, built by the National Institute of Standards and Technology (USA) and maintained by the National Institute for Environmental Studies (Japan). The assessment was expanded to measurement networks contributing to the World Meteorological Organization's Global Atmospheric Watch (WMO/GAW) program as part of off-site comparisons, and excellent agreement was achieved. These efforts contribute to propagating traceability of the national metrology standards among the atmospheric science community, to ensuring comparability of the existing ozone measurements, and to establishing an integrated network of air quality monitoring in Asia.