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.

Evidence-based practice in radiology: knowledge, attitude and perceived barriers to practice among residents in radiology.

AIM: We examinted the attitude, knowledge and perceived barriers to evidence-based practice of radiology (EBPR) among residents in radiology. STUDY DESIGN AND SETTING: We used the McColl questionnaire (1) and the BARRIERS scale (2) to assess the issues among radiology trainees attending an annual refresher course. Ninety six residents from 32 medical colleges from Southern India attended the course. RESULTS: Eighty (83.3%) residents, 55 male and 25 female of age range 24-34 years, consented and returned the questionnaire. The majority of the participants had a positive attitude towards EBPR. However, 45% were unaware of sources for evidence based literature although many had access to Medline (45%) and the internet (80%). The majority (70%) were aware of the common technical terms (e.g. odds ratio, absolute and relative risk) but other complex details (e.g. meta-analysis, clinical effectiveness, confidence interval, publication bias and number needed to treat) were poorly understood. Though majority of residents (59%) were currently following guidelines and protocols laid by colleagues within their departments, 70% of residents were interested in learning the skills of EBPR and were willing to appraise primary literature or systematic reviews by themselves. Insufficient time on the job to implement new ideas (70.1%); relevant literature is not being complied in one place (68.9%); not being able to understand statistical methods (68.5%) were considered to be the major barriers to EBPR. Training in critical appraisal significantly influence usage of bibliographic databases (p<0.0001). Attitude of collegues (p=0.006) influenced attitude of the trainees towards EBPR. Those with higher knowledge scores (p=0.02) and a greater awareness of sources for seeking evidence based literature (p=0.05) held stronger beliefs that EBPR significantly improved patient care. CONCLUSIONS: The large knowledge gap related to EBPR suggests the need to incorporate structured training into the core-curriculum of training programmes in radiology.

Osteopetrorickets.

Rickets is a paradoxical complication of osteopetrosis resulting from the inability of the osteoclasts to maintain a normal calcium-phosphorus balance in the extracellular fluid. Detection of rickets in a child with osteopetrosis is necessary, because treatment of the rickets with vitamin D leads to improvement in activity, decrease in irritability, improvement of appetite, and protects against recurrent respiratory tract infections. If bone marrow transplantation is feasible, then for better results, rickets should be completely treated prior to the transplantation.