When it comes to radiation exposure, there is not much on which the medical community agrees. One exception (and point of consensus) is that children are more vulnerable to the effects of radiation than are adults, and therefore, they deserve the highest level of protection available.
As chair of radiology at Children’s Hospital Los Angeles (CHLA) in California, pediatric neuroradiologist Marvin D. Nelson, MD, MBA, bears the ultimate responsibility for protecting the young people treated in more than 400,000 encounters per year at the 314-bed hospital and level I pediatric trauma center from unnecessary exposure to radiation.
It is a charge that he takes very seriously and that involves developing his institution’s radiation-protection strategy, addressing parental concerns, and eventually creating a pediatric dose record that will stand alongside a child’s immunization record.
“Children are still developing, they have much more radiosensitive organs than adults do, and they are going to spend an entire lifetime with the burden of radiation that we give to them. In children, there is a longer period of time when the effects of radiation can manifest themselves, as opposed to the case of an adult (who is already many years down the road).”
—Marvin D. Nelson, MD, MBA
Not Just Little Adults
The first thing to understand about pediatric patients is that they come in a wide variety of sizes, so pediatric dose recommendations are not one-size-fits-all propositions. “The equipment needs to be modified to accommodate the tremendous changes in the size of children,” Nelson says. “They go all the way from being premature, tiny babies up to adulthood.”
The radiology department adjusts all imaging protocols based on the size of the child, so that he or she receives only as much radiation as necessary to get a diagnostic-quality exam. Radiation exposures “are considerably less than what they are in an adult,” Nelson says.
The primary focus is on three areas where children receive the most radiation: CT exams, fluoroscopy, and nuclear-medicine procedures. The radiologists at CHLA try to substitute other techniques that do not entail the use of ionizing radiation. “If at all possible, we’ll either do an MRI scan or an ultrasound, to avoid the radiation in the first place,” Nelson explains.
Quality-assurance and safety milestones have been put into place so that when the fluoroscope is being used, it automatically shuts off after the time limit set for the exam. “We hope we won’t have to go up to that point, but it will turn off so that the person doing the procedure can’t just blanket irradiate someone indefinitely,” he says.
All equipment undergoes annual inspection and calibration by a physicist to ensure that output from the x-ray tubes is what it should be. Shielding is also checked annually for leaks. Protocols are set for each piece of equipment based on size and weight, and these are typically reviewed once a year. As part of the ACR® accreditation process, CT protocols, sample studies, and technique parameters are sent, at regular intervals, to the ACR. “This is now becoming much more of a requirement, across the country, to get reimbursement,” Nelson notes.
Building a Dose Record
In compliance with California’s Medical Radiation Safety Act of 2010 (initially SB 1237), radiologists at CHLA have been recording the dose indices of every CT exam in the radiology report since July 1. Nelson, though, is leading an initiative to create an individual dose record—for every patient—that will include data not just from CT exams, but from every exam involving radiation that he or she undergoes.
“We are trying to set up a system, in our department, where we can capture the dose information from every radiation exam and create an individual patient record that will record both year-to-date and lifetime exposure,” he states. “It will be a lot like a child’s immunization record that we will be able to keep and track forward.”
In the process of recording relevant patient information, CHLA will accumulate a database for the purpose of researching the effects of medical radiation exposure. “We can begin to be able to make much more educated statements about the long-term effects of radiation as we go forward, rather than just making these extrapolations based on the data from the survivors of the atomic bomb in Hiroshima,” Nelson says.
He adds, “It is a very challenging project because you have to deal with all of the