Effective Dose Display System in Gastric Cancer X-ray Screening.

PURPOSE: The purpose of this study is to build a system for effective dose display immediately after the gastric cancer X-ray screening. MATERIALS AND METHODS: The regression equation of effective dose and dose area product (DAP) was introduced from the data of 500 persons including DAP and effective dose calculated using program for X-ray Monte Carlo. RESULTS: The effective dose was 5.39 mSv of median, 1.18 mSv of minimum, and 38.38 mSv of maximum. The regression equation was Y=0.354+0.0003772X (Y: effective dose, mSv, X: DAP, mGy cm2). Using the regression equation, the effective dose can be estimated from DAP and displayed just after the individual screening. CONCLUSIONS: "Effective dose display system" was constructed to display effective dose immediately after gastric cancer X-ray screening. This system is on the way to be reformed by improving the regression equation on larger data.

Relationship between Bone Mineral Density and Body Composition Estimated by Dual-Energy X-ray Absorptiometry: Comparison between Groups Aged 20-39 and 40-59 Years.

Bone mineral density (BMD) is affected by lean body mass and body weight to various degrees in the course of aging. The attempt of this study is to determine the optimal time to begin prevention of osteoporosis. In this study, female hospital employees aged 20-59 years were divided into 2 age groups, 20-39 years and 40-59 years based on age at peak BMD, and the relations of total BMD, subtotal BMD and lumbar spine BMD to lean body mass and body weight were examined in both groups. Subtotal BMD was calculated by subtracting head BMD from total BMD along with whole body measurement. While persistent positive correlations were found among all factors in the 20-39-year-old group, subtotal BMD and lumbar spine BMD were positively correlated to lean body mass in the 40-59-year-old group. Thus, lean body mass and body weight appeared to exert a profound influence on subtotal BMD in those aged 20-39 years, but lean body mass in those aged 40-59 years. Lean body mass appears to provide the best prediction of subsequent development of osteoporosis.

Evaluation of GAFCHROMIC EBT2 dosimetry for the low dose range using a flat-bed scanner with the reflection mode.

Recently developed radiochromic films can easily be used to measure absorbed doses because they do not need development processing and indicate a density change that depends on the absorbed dose. However, in GAFCHROMIC EBT2 dosimetry (GAF-EBT2) as a radiochromic film, the precision of the measurement was compromised, because of non-uniformity problems caused by image acquisition using a flat-bed scanner with a transmission mode. The purpose of this study was to improve the precision of the measurement using a flat-bed scanner with a reflection mode at the low absorbed dose dynamic range of GAF-EBT2. The calibration curves of the absorbed dose versus the film density for GAF-EBT2 were provided. X-rays were exposed in the range between ~0 and 120 mGy in increments of about 12 mGy. The results of the method using a flat-bed scanner with the transmission mode were compared with those of the method using the same scanner with the reflection mode. The results should that the determination coefficients (r (2) ) for the straight-line approximation of the calibration curve using the reflection mode were higher than 0.99, and the gradient using the reflection mode was about twice that of the one using the transmission mode. The non-uniformity error that is produced by a flat-bed scanner with the transmission mode setting could be almost eliminated by converting from the transmission mode to the reflection mode. In light of these findings, the method using a flat-bed scanner with the reflection mode (only using uniform white paper) improved the precision of the measurement for the low absorbed dose range.

Measurements and evaluation of proximal femoral bone mineral density with dual energy X-ray absorptiometry.

Proximal femoral bone mineral density (BMD) can be measured by dual energy X-ray absorptiometry method in the neck, trochanter, intertrochanter, total and Ward's triangle area. Ward's triangle area of the proximal femur is a smaller area to measure than the others, and the position varies, depending on the status of inner rotation of the target leg. In this study, the measurements of the proximal femoral BMD in women were carried out on the neck, trochanter, intertrochanter, total and Ward's triangle area with the, subjects' legs turned 15 degrees toward the inside. The Ward's BMD were measured using Ward's cognitive method, in which the measured BMD were compared among age groups of 50-59, 60-69, 70-79 and 80-89 to determine whether this process could reveal decreased femoral BMD in elderly women. The correlation between BMD and age was tested using the Pearson correlation coefficient. In all measured parts, the BMD of women age 50-59 were significantly higher than those of women age 80-89. The correlations between BMD and age were negative in all measured parts, and the most negative correlation was between age and Ward's BMD. The study using Ward's cognitive method showed an inverse correlation between Ward's BMD and age in women.

Sonographic assessment of hyoid bone movement during swallowing: a study of normal adults with advancing age.

Our aim in this study was to evaluate hyoid bone movement trajectories and the age-related changes during swallowing in healthy subjects by ultrasonography. Data were obtained from 30 healthy volunteers (15 men, 15 women) in three age groups (20-39, 40-59, 60-79 years). The subjects were examined while sitting in an upright position, with the back against a wall to control movement. The transducer was placed in a longitudinal scan above the larynx. The subjects were then given 5 mL of mineral water. The water bolus was held in their mouth until they were forced to do a rapid swallow. The imaging was repeated five times for averaging. The movement was divided into 4 phases: slowly ascending phase (A-B, Elevation); rapidly ascending phase (B-C, Anterior); temporary pause phase (position of maximum rise, Remain); and rapidly and slowly descending shifts toward the resting position phase (C-D, Return). We easily visualized the hyoid bone trajectory by using ultrasonography. In all cases, ultrasonographic analysis of the hyoid bone was confirmed to have a similar trajectory, as determined with videofluoroscopy. The average swallowing duration measurements increased with age. The measurement of the maximally elevated point of the hyoid bone decreased with age. The movement of the hyoid bone during swallowing can be visualized by US. The trajectory of the hyoid bone in sagittal section indicated the capability of swallowing, and may detect some anomalies in swallowing.

Diagnostic validity of high-density barium sulfate in gastric cancer screening: follow-up of screenees by record linkage with the Osaka Cancer Registry.

BACKGROUND: The use of high-density barium sulfate was recommended by the Japan Society of Gastroenterological Cancer Screening (JSGCS) in 2004. We evaluated the diagnostic validity of gastric cancer screening that used high-density barium sulfate. METHODS: The study subjects were 171 833 residents of Osaka, Japan who underwent gastric cancer screening tests at the Osaka Cancer Prevention and Detection Center during the period from 1 January 2000 through 31 December 2001. Screening was conducted using either high-density barium sulfate (n = 48 336) or moderate-density barium sulfate (n = 123 497). The subjects were followed up and their medical records were linked to those of the Osaka Cancer Registry through 31 December 2002. The results of follow-up during 1 year were defined as the gold standard, and test performance values were calculated. RESULTS: The sensitivity and specificity of the screening test using moderate-density barium sulfate were 92.3% and 91.0%, respectively, while the sensitivity and specificity of the high-density barium test were 91.8% and 91.4%, respectively. The results of area under receiver-operating-characteristic (ROC) curve analysis revealed no significant difference between the 2 screening tests. CONCLUSIONS: Screening tests using high- and moderate-density barium sulfate had similar validity, as determined by sensitivity, specificity, and ROC curve analysis.

Sonographic visualization of the normal stomach: left lateral decubitus position.

The aim of this study was to evaluate the usefulness of an imaging technique that takes into account the effect of posture change on the stomach in transabdominal ultrasonography (US). A total of 240 adult patients (healthy subjects) underwent gastric US. In all subjects, the lesser curvature of the stomach (LCS) and left liver were measured in two different positions [left lateral decubitus (LLD) and supine]. The maximal length of the LCS was defined as the measured range between the cardial orifice and the left liver tip. The anteroposterior length (L1) and maximal longitudinal length (L2) of the left liver were determined on epigastric longitudinal scans. The mean LCS in the supine and LLD positions was 90.2 +/- 34.7 and 124.4 +/- 44.4 mm, respectively. The mean L1 in the supine and LLD positions was 54.0 +/- 12.7 and 65.6 +/- 14.4 mm, respectively. The mean L2 in the supine and LLD positions was 84.3 +/- 18.5 and 107.0 +/- 25.8 mm, respectively. The results for the measured LCS, L1, and L2 differed significantly between the supine and LLD positions (P < 0.05). This study demonstrated that the LCS could be clearly visualized on longitudinal scanning in the LLD position. Therefore, this position may potentially be more useful for gastric US, even in view of the limitations of this approach.