Radiation dose, you can’t see it, smell it or even touch it, but it’s there every time you receive an X-ray, a CT scan or undergo any ionizing imaging exam. The dosage of radiation received during these exams is a concern across all age groups, but children in particular have been shown to be more susceptible to developing cancer as a byproduct of X-rays compared to their adult counterparts. In a study referenced by the RSNA’s monthly journal, Radiology, researchers found an increased risk of childhood acute lymphocytic leukemia attributed to exposure of patients to plain X-rays and an increased risk of breast cancer linked to scoliosis exams.
In recent years, there has been a growing emphasis placed on understanding the effects of radiation dose in both children and adults. This movement was further galvanized by an FDA safety investigation into CT brain perfusion scans that revealed in some cases patients were receiving radiation doses that were approximately eight times the expected level. While this event was related to a single diagnostic test at one facility, the FDA felt the situation reflected a more widespread problem and issued recommendations for radiology departments as a result of the study. The FDA’s involvement in radiation dose concerns also helped to spur awareness of two educational campaigns already in existence, Image Gently for pediatric patients and Image Wisely for adults.
The Image Gently campaign, a result of effort from the Alliance for Radiation Safety in Pediatric Imaging, serves to remind both imaging professionals and the general public of key differences between pediatric and adult imaging. The campaign has garnered a tremendous amount of attention and concern around dose exposure in CT scans, but it is also important to remember how this effective movement relates to general X-ray exams. This becomes especially true when considering X-rays are the most commonly ordered exam for children of all the radiology modalities (X-ray, CT, MRI, and Nuclear Medicine).
While the Image Gently campaign contains several different initiatives covering all areas of pediatric radiation dose, one in particular, known as Back to Basics, focuses on protocol recommendations, enhanced communication and best practices in general imaging departments. It encourages the use of proper collimation and shielding when possible and eliminating the use of a grid when X-raying anatomy that is less than 10-12cm thick. To seasoned radiographers this means dusting off the cobwebs from the old calipers and proactively measuring pediatric patients prior to performing exams. This Back to Basics section also focuses on checking exposure indicators and image quality.
All these reminders are encouraging radiographers to take into account that smaller, younger patients require less dose. While almost all radiographers can be given the benefit of the doubt that they are taking into consideration pediatric patients, there has been attention to the subject of “dose creep” related to CR (Computed Radiography) and DR (Direct or Flat Panel Detector technology). CR and DR both have a generous dynamic range which allows for an overexposed radiographic image to be manipulated into a very sharp diagnostic radiograph most times. This is unlike previous generations of film/screen X-ray where images would appear extremely dark and unreadable by a radiologist when overexposed.
This “gradual creeping up of the dose” happens when radiographers find themselves dialing up the exposure settings in order to guarantee a better quality radiograph with CR and DR instead of taking the chance of underexposing. An underexposed image can result in a noisy and grainy image that is unacceptable for reading and making a diagnosis. Over time, technologists may in effect be using more radiation than is actually necessary in an effort to avoid repeating the exposure altogether. When this “dose creep” theory is applied to pediatric imaging where this patient population is known to be more sensitive and vulnerable to the biological effects of the dose they receive when compared adults we can begin to understand the very real issue at hand.
Thankfully the resources provided by the Image Gently Campaign and commitment by the FDA to both educate and reduce radiation dose in children is leading to nationwide changes. The FDA has already proposed medical equipment manufacturers be required to include a minimum of four pediatric settings such as newborn, 1-yr. old, 5-yr. old and 12-year old. Along with this proposal, the FDA also has an area of their website dedicated to Pediatric X-ray Imaging where the agency outlines benefits vs. risks, offers information for both patients and healthcare providers, as well as providing an avenue for voluntary reporting of adverse events or problems.
From downloadable medical imaging record logs to patient education brochures available at Imagegently.org, the wealth of resources offered by the campaign can assist in providing knowledge and facilitating engagement of providers and patients. Collectively this helps in the ultimate goal of performing the most appropriate imaging exam that provides the best quality at the lowest possible dose to the child.
Note from the Author: As the topic of radiation dose is on the front line of attention and concern in the healthcare arena, I’d love to get your feedback on what your institution has implemented in the area of protocols, policies and education of lowering patient dose while maintaining quality images.