Protecting the Most Vulnerable Patients: Children’s Hospital Los Angeles

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 different exams that we do for all of the different ages and sizes of patients. Dealing with exposure and converting it into dose for the child is a tricky thing, and it is going to involve an awful lot of work. We are just getting started on it.” Nelson believes that it is just a matter of time before federal regulators mandate a dose record. He says, “Now that California has mandated we record dose for all CT exams, it is only five years down the road that regulators will require an individual dose record. We might as well get out in front of it now and do it right, while we have the time, rather than being forced to do it in a short amount of time—and it’s the right thing to do for the kids.” Assembling the Elements The ultimate goal, Nelson says, would be to have a dose record present when a referring physician orders an exam, along with an indicator that would inform the referring physician of how much radiation a patient had received for the year to date and over his or her lifetime. “We’ll set some standards for those, all of which don’t exist right now,” Nelson adds. The task is challenging on many levels, beginning with achieving interoperability among information systems. Nelson is working with his PACS vendor (FUJIFILM Medical Systems USA) and a modality vendor “to get ahead of this game and start working on developing this, in the form of product lines, from their side,” he says. First, the pertinent data must be extracted from the medical record to permit making a proper dose estimate. “That number is going to change with the age of the patient and the size of the patient,” Nelson explains. “You can’t just put a blanket number in for every CPT® code that uses radiation because it’s going to vary based on the size, weight, and age of the child.” Second, all of the imaging technology that uses radiation must be capable of providing exposure data. Nelson’s team is working to equip fluoroscopy systems and portable radiography units with dosimeters to facilitate that process. Third, all of the data must be translated into a biologically meaningful number to express actual patient dose. This entails working with radiation biologists to translate the exposure data into an effective dose strategy that everyone in the radiology community will agree is the standard—for every single exam. “It is not going to happen overnight,” Nelson says. “It’s something that is probably going to take five years to get done.” Fourth, the information needs to be presented to referring physicians in a way that is readily understood, with the ability to inform decision making. “That’s really the goal,” Nelson says. “Then, they can make intelligent decisions about what exams need to be done or call radiologists for a consultations. That’s the point where the decision making really has to happen in order to affect the amount of radiation a child will receive in the long run. We’re taking a stab at it. It’s going to require a lot of work and a lot of resources to make it happen.” Reassuring Parents Many parents arrive at CHLA with a certain degree of knowledge about the dangers of radiation exposure, and they often want to speak to the radiologist about the radiation dose that the child is going to get, Nelson reports. In this case, it is the job of the radiologist to put this issue in perspective for parents and to reassure them that everything possible is being done to mitigate the risks. To frame the question, Nelson and colleagues estimate what the exposure will be and then translate that into terms that a parent can understand—for instance, the number of hours of standing in sunlight that would be the equivalent of the radiation load of the imaging procedure. “We provide a measure they can understand to give them an idea of how much radiation we are talking about; if you live in Denver, Colorado (a mile above sea level), you get much more background radiation than you do if you live at sea level,” Nelson explains. “You get a lot of radiation, for instance, when you fly in an airplane from Los Angeles to New York.” If a child is scheduled for a CT exam, the radiologists might discuss the amount of radiation involved in radiography (which is usually fairly small) and explain how many radiographs are the equivalent of a CT exam. This also is an opportunity to explain what the amount would be for the same exam in an adult and how much it is cut back for the child (based on size and the diagnostic question), as well as the measures taken to protect the radiosensitive organs. “We often put shields on the thyroid, put shields over the breast tissue for certain exams in girls, and use pelvic shields to cover the ovaries and the testicles, to try to protect those areas as well,” Nelson explains. Invariably, parental concerns heighten after a news report of an overradiation event. Occasionally, Nelson gets a call from a parent asking whether it’s necessary to bring a child to CHLA (rather than the local hospital) for an exam; he tells the parent what questions to ask to be certain that the proper pediatric protocols will be used. “Everybody is now thinking about this, and all of the equipment manufacturers are focused on dose reduction, which is nice to see,” he says. “We’ve already seen a huge reduction in CT radiation dose, based on improved technology. I think there are going to be some great changes coming in the future along these lines.”Cheryl Proval is editor of Radinformatics.com and Radiology Business Journal.