Assessment of safety culture in radiotherapy facilities using safety performance indicators.

This paper describes the development of the Safety Performance Indicators (SPIs), the methodology for assessment of the safety culture of radiotherapy institutions using SPIs and common strengths and common areas for improvement. SPIs were categorized into eight sections which all together contain 23 attributes and each attribute has scoring criteria from 0 to 2 (in steps of 0.5). The maximum absolute cumulative score of SPIs was 46. A relative cumulative SPIs score of >80% indicates an institution strong commitment towards safety while score <50% indicates need for additional guidance to enhance safety culture. The assessment using SPIs was conducted for 17 radiotherapy institutions. The methodology of assessment includes interactive discussion, direct observations and document analysis. The relative cumulative SPIs score of seven institutions was found to be >80% while it was found in the range of 67.0% to 80% for the remaining ten institutions. Institutions were communicated about the cumulative SPIs score, areas of strengths, and areas for improvement. SPIs were found to be a good tool for safety culture assessment and can be utilized by the radiotherapy institutes for self-assessment to identify the areas of improvement. Based on SPIs score, regulatory body can grade the institutions from a radiation safety compliance point of view.

Methodology for shielding design and evaluation for container scanners.

There has been an increase in the use of high energy photon beam for container scanners in many countries for multi purposes such as detecting high atomic number materials which might be nuclear materials, drugs, high explosive materials and other contrabands etc. High energy photon beams generally 6 and 9 MV can be used for scanning such materials. However, it is important to ensure that radiation level beyond the container scanner installation is within the permissible dose limit specified by the national competent authority for the protection of public and radiation workers. In this paper, challenges in the biological shielding during the installation of high energy X-ray system for scanning vehicles containing suspected materials are discussed. The purpose of the present study is to develop a methodology for shielding design and evaluation for container scanner installations. The basic concept pertaining to shielding evaluation of radiotherapy installations provided in National Council on Radiation Protection and Measurements (NCRP)/International Atomic Energy Agency (IAEA) reports are referred, and appropriately used to calculate optimized shielding thicknesses requirements for container scanner installation. Workload is estimated based on number of containers scanned, machine ON time and dose rate at 1 m. The shielding evaluation includes use of beam stopper in the primary beam, scattering by heterogeneous metallic scrap materials or any other suspected materials contained in the vehicle and their impact on the thickness of shielding walls. A model lay out plan to be used for installation of container scanner is developed. A methodology for shielding evaluation for various protective walls and ceiling of this model is also discussed. The study provides basic requirement for designing a structural room for installing 9MV container scanner from radiological safety view point.