Evaluation of Radiation Dose Reduction and its Effect on Image Quality for Different Flat-Panel Detectors.

Purpose: To evaluate the image quality of semi-anatomical chest radiographs acquired using low radiation doses from seven different flat-panel detector (FPD) systems. Materials and Methods: Radiographs of a semi-anatomical chest phantom were acquired at 70 and 110 kVp using 7 different FPDs from 5 vendors. Radiation doses were measured using a dose-area-product (DAP) meter. To standardize measurements across all FPDs, DAP value of 51.05 µGym2 obtained at 70 kVp and 9.43 µGym2 at 110 kVp was used as reference in this study. Radiation doses were reduced by manually adjusting mAs for both tube potentials in all FPD systems to achieve acceptable image quality. Contrast-to-noise ratio, signal-to-noise ratio and figure of merit (FOM) in lung, heart, and diaphragm for all images were analyzed. Results: In comparison with set standard protocol, radiation dose reduction of 20%, 21%, 21.6%, 59.5%, 60.7%, 62.2%, and 67.6% with optimal image quality was observed in Prognosys Prorad, GE Definium 8000, Siemens Fusion, Fujifilm FGX, Fujifilm FGXR, Philips Digital Diagnost and Siemens Aristos at 70 kVp. At 110 kVp, dose reduction of 15.7% and 34.8% was possible only for Philips Digital Diagnost and Siemens Aristos. FOM was high at 110 kVp even when radiation doses were reduced by a factor 2 when compared to 70 kVp in all digital radiography systems. Conclusion: This study demonstrates the feasibility of using a semi-anatomical chest phantom in the optimization of radiation dose and image quality. The FOM was a good indicator in assessing image quality between different detectors.

Significance of single and multi-voxel 1H magnetic resonance spectroscopy in the quantification of myocellular lipid in young non-obese Asian Indian males.

To prospectively assess intramyocellular lipids (IMCL) and extramyocellular lipids (EMCL) using single voxel spectroscopy (SVS) and multi voxel magnetic resonance spectroscopy (MVS) in soleus muscle and correlate results with metabolic variables in non-obese (BMI < 23 kg/m2) Asian Indian males. Thirty one patients with diabetes (cases) and twelve normoglycaemic subjects (controls) underwent point resolved spectroscopy sequence (PRESS) of soleus muscle using SVS and MVS in a 3 T MRI scanner. Visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were measured from MRI images and body composition was measured from dual-energy x-ray absorptiometry (DXA). The mean IMCL from SVS and MVS were 1.6% and 2.6% in cases and 2.3% and 3.4% in controls respectively. The mean EMCL from SVS and MVS were 1.8% and 3% in cases and 1.5% and 3% respectively in controls. A significant correlation between IMCL and total fat mass (rho = 0.42, p < 0.01) and total body fat (rho = 0.46; p < 0.01) were observed in cases while using the SVS technique and no correlations were found in the MVS technique. The SVS showed significant correlations between total myocellular lipids with VAT and SAT in cases alone. Total myocellular lipids acquired using both techniques showed a significant correlation with BMI, waist circumference, total fat mass, total body fat and truncal fat in cases alone. Quantification of IMCL of soleus muscle using the SVS technique is useful in studying the relationship with metabolic markers in non-obese Asian Indians with diabetes.

A Study on the Use of Radiation-Protective Apron among Interventionists in Radiology.

OBJECTIVE: Radiation-protective aprons are commonly used by interventionists to protect against the harmful effects of ionizing radiation. Choice of appropriate aprons with respect to lead equivalence and weight is necessary for effective protection and reduced physical strain. This study evaluates the knowledge and practice of using radiation-protective aprons by interventionists. MATERIALS AND METHODS: Ninety-one interventional radiologists who attended an annual interventional conference were provided with a questionnaire which included age, years of experience, area of expertise, type and weight of apron used, and physical strain caused due to the use of apron. RESULTS: About 14.3% of the interventionists practiced in an angiographic suite for less than an hour a day, 45% for 2-4 h, 21% for 4-6 h, 10% for 6-10 h, and the rest above 10 h/day. About 68% of the interventionists wore 0.5 mm lead-equivalent (Pbeq) aprons; 15.4% with 0.25 mm Pbeq; about 5.5% with 0.35 mm Pbeq aprons, and the remaining were not aware of the lead equivalence. About 47% reported that they had body aches due to wearing single-sided aprons. Interventionists working more than 10 h/day wearing single-sided lead apron predominantly complained of shoulder pain and back pain. CONCLUSION: A large fraction of interventionists reported that they had physical strain. It is suggestive for interventionists to wear correct fit and light-weight aprons with appropriate lead equivalence.