Good practices in radiography
Frequently asked questions by the health professionals
? Is it a good practice to select "high speed"?type intensifying screens that require relatively low exposure and use them for all radiographic procedures in my facility??
? How does performing a reject analysis?in radiography reduce unnecessary exposure to patients??
? Does the quality of the chemical processing of radiographic film have any effect on the radiation exposure of a patient??
? Is the radiation exposure to a patient affected by the size of the image (area covered by the X ray beam)??
? Why should we no longer shield patients routinely?
? Doesn’t shielding reassure my patients?
? Is it a good practice to select "high speed"?type intensifying screens that require relatively low exposure and use them for all radiographic procedures in my facility?
No.
While high-speed intensifying screens are appropriate for many examinations, especially where patient exposure is a concern, they do not produce the necessary visibility of detail that is required for some types of radiography, such as of the chest and the skeletal system. The appropriate intensifying screens and film for each type of clinical examination should be specified in the procedure manual for the facility.
It is desirable to have a selection of intensifying screens available so that an appropriate one can be selected for a given procedure. Radiographers should have a good knowledge of the characteristics of the intensifying screens available in their facilities. The intensifying screens that provide optimal imaging for each examination with regard to image information and patient exposure should be identified and made known to the staff.
? How does performing a reject analysis?in radiography reduce unnecessary exposure to patients?
A reject analysis is performed by saving all ‘rejected’ films and then evaluating them periodically to determine the cause of the rejects and repeated exposures. The objective is to reduce the number of repeated examinations by correcting technical problems and improving the skills of the staff. A reject analysis is an important function in a quality assurance programme in radiology.
When using digital radiography, procedures should be established for identifying and analyzing all images that were repeated because of problems with quality, positioning, etc. This information should be used for training and guidance to reduce the need for repeated exposures.?
? Does the quality of the chemical processing of radiographic film have any effect on the radiation exposure of a patient?
Yes, maintaining high-quality film processing reduces unnecessary patient exposure in several ways. First, if films are underdeveloped and appear underexposed, the usual reaction is to increase the exposure of the patient and the film in an attempt to compensate. This results in unnecessary patient exposure. Second, if the processing is not properly controlled and fluctuates with time, some films might be incorrectly exposed and require repeating. This results in unnecessary exposure to patient. The appropriate action is to have a good film processor quality control programme that ensures both adequate and consistent processing.
? Is the radiation exposure to a patient affected by the size of the image (area covered by the X ray beam)?
Yes.?
The advantage is that by reducing the area covered by the X ray beam (collimation), tissues and?organs that do not need to be evaluated are kept outside the direct beam. While there will be some internal scatter of X rays in the body, which potentially can reach areas close to the directly exposed area, radiation dose from such scattered radiation is small. Significant dose reduction to?tissues and organs outside of the area that needs to be evaluated can be achieved with beam collimation.
? Why should we no longer shield patients routinely?
As with all areas of medical practice, the use of patient contact shielding should be evaluated from a risk–benefit perspective. Patient contact shielding was previously employed routinely during medical exposures to reduce the potential risks from radiation. However, with the advances in medical imaging technology over the past 70 years, the amount of radiation being delivered during X ray examination has dramatically decreased. Also, incorrect or unintended placement of shielding in relation to the anatomy of interest can obscure important details, leading to repeat exposures. The dose to internal organs outside of the field of exposure results from internal scattering within the patient, making radiation exposure savings from shielding negligible. When used with automatic exposure controls, shields that partially or fully cover detectors may increase radiation exposure to other organs and tissues. Therefore, currently, the risks from routine use of shielding are believed to outweigh benefits in imaging. Optimization is primarily achieved through careful consideration of other technical factors such as the collimation and appropriate exposure factors selection.?
? Doesn’t shielding reassure my patients?
Scientific evidence should be the basis for clinical practice. While there may be, based on past practice, an expectation for routine shielding, the best reassurance for your patients and caregivers is an appropriate explanation of the optimization steps that will be followed for their particular examination. This can include an explanation of factors that are behind the change in practice. However, there will be situations that require professional judgement based on the individual patient and circumstances that might warrant shielding. This includes psychological safety for patients or parents/caregivers, especially if shielding is placed remotely (not adjacent to) from the examined area.??