Radiation Exposure: Connecting the Dots

When it comes to nuclear medicine and molecular imaging procedures, the Society of Nuclear Medicine and Molecular Imaging shares a straightforward message—the right dose should be given to the right patient at the right time. 

As always, patients large and small should be exposed to the lowest possible amount of radiation that will provide the appropriate diagnostic information. At the same time, physicians need to recognize that a fear of radiation often is more detrimental than failure to undertake a procedure.

Reaching this goal hinges on careful connection among health IT, imaging systems, education and policy.

The EHR connection

In May, Salt Lake City-based Intermountain Healthcare launched a system that measures the cumulative radiation dose that patients receive over their lifetimes from higher-dose procedures—CT studies, nuclear cardiology, cardiac catheterization procedures and angiography—and reports them in patients’ EHRs.  

Through this initiative, cumulative exposure data—for procedures starting in mid-2012—are available to patients and physicians. Patients can view their radiation histories through Intermountain’s online portal. The goal is to provide radiation exposure information to patients and inform them about Intermountain’s efforts to increase radiation safety.

“As we put forth the idea, there was a fair amount of discussion whether it was wise to let this information out to patients, whether they would be able to understand what the data meant, and whether there would be liability issues,” says Keith S. White, MD, medical director of imaging services at Intermountain. However, as the initiative rolled out, “It has been well received. [Patients] appreciate that we are working on it.”

Data from approximately 220,000 CT scans and radiology procedures will be reported in the EHR annually. Physicians could use these data to decide if an MR exam could be substituted for a CT scan or if a lower radiation dose could be used for certain cardiovascular procedures.

Intermountain built its own software, which White describes as a big undertaking because each modality had a different process and way to estimate radiation dose. For cardiac PET and SPECT procedures, each facility provides the primary cardiac protocol with the radioisotope dosage range. These factors are then analyzed with the ICRP radiation dose estimate for total body effective dose in mSv units—which are then automatically transferred to the radiation database.  

Operational processes for the cardiac cath labs and radiology special procedures laboratory were crafted as well. For example, after an imaging procedure, a technologist reads the value of the dose area product (DAP) from the imaging console and either enters it manually through a web-enabled reporting tool or in a data entry field in the radiology information system. 

The patient connection

Physician referral and patient education also was implemented during the rollout. 

Intermountain’s educational materials inform physicians on how to reassure patients about necessary and indicated imaging procedures and access its web-based patient education resources.

The guide urges physicians to explain that current research shows a large single dose of radiation (>100 mSv) carries a risk of carcinogenesis, but it remains unclear if the level of risk is the same if a patient reaches this lifetime exposure from several smaller doses (10 to 15 CT scans). The estimated dose and estimated lifetime risk of fatal cancer also requires disclosure. For example, pelvic vein embolization in the cath lab exposes a patient to an estimated 60 mSv with a 1 in 400 estimated lifetime risk of cancer.

The guide suggests physicians provide context on the dosage. For instance, Utah residents are exposed to 4mSv per year from natural sources, so a cumulative exposure of 20 mSv is equivalent to five years in one’s natural surroundings. 

In addition, Intermountain developed standardized care process models for CT pulmonary angiogram (CTPA) for suspected pulmonary embolism and cardiac radionuclide imaging. The CTPA module directs the ordering physician through a cascade of decision points based on clinical and laboratory investigations. Specifically, it uses the Revised Geneva Score, results of D-Dimer, patient history of allergy to contrast or renal disease to guide physician decision-making to perform no imaging, perform lower extremity Doppler ultrasound, or CTPA. 

For cardiac SPECT and PET, Intermountain produced specific ordering sheets, based on American College of Cardiology guidelines. Intermountain is working to incorporate this process into its computerized physician order entry system, White says. 

The modality connection

Radiation dosage awareness has come a long way because of dose registries like the American College of Radiology’s Dose Index Registry, says Matthew R. Palmer, PhD, medical physicist, department of radiology at Harvard Medical School Beth Israel Deaconess Medical Center in Boston.

While the medical center has yet to join the dose registry, he says its strategy involves regular internal reviews of optimization. The type and amount of radiopharmaceutical administered is recorded the EHR record, but they don’t audit it per dose. However, they reconstruct imaging data if a question about dose arises. 

In the meantime, the department is replacing its only PET/CT system, which is 10 years old, with the overall goal of reducing the average dose from 16 mSv to 8 mSv. “Dose was a big factor in the decision to replace the scanner and in determining which scanner to buy,” Palmer says.

The policy connection

California’s first-of-its-kind radiation dose tracking law spotlights the importance and awareness of radiation dose. As of July 1, 2012, state facilities are required to record the volume CT dose index and the dose length product on every CT scan by either recording the dose within the patient’s radiology report or attaching a protocol page. The law requires facilities to notify the state of a repeat CT examination when certain dose values are exceeded or irradiation of a body part other than that intended by the ordering physician. 

Although the law has gone into effect with little fanfare and compliance has not been an issue, Bob Achermann, executive director, California Radiological Society, questions whether its implementation has reduced excessive radiation dose. “Does it accomplish what the proponents were concerned about: excessive radiation dose? It really doesn’t because you could theoretically provide an excessive dose and all you have to do is record it. That’s the shortcoming of the bill.” 

 Some software firms have developed systems to automatically populate the dose field in the report. Michael Puckett, MD, chief medical officer of San Diego Imaging Group, says the main advantage of having the fields auto populate is accuracy.

It appears the law has not spurred requests for radiation exposure data. Noting that his group covers seven hospitals, including Rady Children’s Hospital San Diego, Puckett says, “I have not heard of a single physician or patient inquiry regarding the dose information in our reports.” Likewise, Achermann says litigation concerns have not come to light and few other states have expressed interest in this policy. 

However, as more is done to connect the dots to reduce radiation dosage, a picture will emerge compelling legislatures and practices to put more effort into alleviating risks while still delivering quality care.