Radiation Safety Awareness

Evidence is mounting that an individual's risk of developing a cancer is linked to exposure to ionizing radiation above a certain threshold. There are predominantly three testing modalities considered to deliver the most significant dosages of ionizing radiation: CT scanning, PET scanning, and myocardial perfusion imaging, also referred to as a nuclear stress test. To safeguard our members, and assist our network physicians in doing the same, Highmark is launching a Radiation Safety Awareness Program. This program will identify for you those members who have been exposed to a threshold amount of ionizing radiation. 

Introduction

As a physician, you want to keep your patients safe and healthy. To support you in this goal, Highmark will launch a Radiation Safety Awareness Program on March 1, 2011 in conjunction with National Imaging Associates (NIA), our nationally recognized Radiology Benefits Manager. Through this program, Highmark will issue proactive alerts to positively impact patient safety and raise awareness regarding radiation exposure.

As you know, radiation exposure from medical imaging is a rapidly growing patient safety issue. Patients are now exposed to nearly six times more radiation from medical diagnostic tests than they were in 1980. The largest contributors to the increase in medical radiation exposure are CT scans and nuclear medicine.

How will my patient be identified?

At-risk patients are identified through Highmark radiology claims data, which are accumulated over time and do not capture any radiation exposure that occurred when the patient did not have Highmark coverage. Members undergoing cancer treatment and those age 65 and older are not included.

"At-risk" patients are those with cumulative radiation exposure (Dose Limit) equal to, or exceeding, 50 millisieverts (mSv) — a level that has been identified as causing a statistically (epidemiologically) significant increased risk of developing radiation-associated cancers. For more information on millisieverts, see below.

How am I notified if one of my patients is identified at risk?

You will be notified when you request a preauthorization by telephone, or through notification presented during the imaging authorization function on NaviNet. At that time, you will be offered an NIA peer discussion should you want to discuss the case with another physician. In addition, a Dose Limit Threshold Notification will also be sent via fax or mail with the authorization or adverse determination letter. 

Important Note: The patient's level of radiation exposure does not impact the preauthorization or decision-making process for requested imaging studies.

How can I use this information when ordering diagnostic testing?

  • Consider the risk versus the benefit of the radiology study.
  • Consider how the results of this study will help in managing this patient.
  • Consider if this ionizing radiation study is the best one to perform.
  • Consider if there are other tests such as ultrasound, laboratory, or endoscopy testing which would be a more appropriate initial investigative study.
  • Carefully consider the necessity of repeating a CT scan, especially in young girls and young women, due to the radiation dose to breasts and ovaries.
  • Be aware of a patient's prior history of imaging studies.
  • Consider discussing this information with patients as this may enable them to take a more active role in their health care.

How is radiation exposure measured?

Radiation exposure estimates are measured in millisieverts (mSv). Radiation "effective dose" is the amount of radiation received by the patient and depends on many factors including distance from the source, time of exposure, overall body and organ size, location and nature of tissue exposed. Effective dose is designed to be proportional to a generic estimate of the overall harm to the patient caused by the radiation exposure. The effective dose allows for a rough comparison between different CT scenarios but provides only an approximate estimate of the true risk. Given these variables, there is some variation in the amount of radiation received from similar medical procedures. However, studies suggest a statistically measurable increase in cancer occurrence at cumulative radiation effective dose levels of 50 mSv. Reaching this effective dose (Dose Limit) is not uncommon in patients having multiple CT and/or nuclear imaging studies. For comparable reference, note that federal health standards limit workers' exposure to whole-body ionizing radiation to 50 mSv per year.

Exposure of Low-Does Ionizing Radiation from Medical Procedures *

Medical Imaging Procedures with Largest Contribution to Cumulative Effective Dose **
Procedure Average Effective Dose Annual Effective Dose per Person Proportion of the Total Effective Dose from All Study Procedures
Myocardial perfusion imaging 15.6† 0.540 22.1
CT of the abdomen 8.0 0.446 18.3
CT of the pelvis 6 0.297 12.2
CT of the chest 7 0.184 7.5
Diagnostic cardiac catheterization 7 0.113 4.6
Radiography of the lumbar spine 1.5 0.080 3.3
Mammography 0.4 0.076 3.1
CT angiography of the chest (noncoronary) 15 0.075 3.1
Upper gastrointestinal series 6 0.058 2.4
CT of the head or brain 2 0.049 2.0
Percutaneous coronary intervention 15 0.043 1.8
Nuclear bone imaging 6.3 0.035 1.4
Radiograph of the abdomen 0.7 0.028 1.1
CT of the cervical spine 6 0.020 0.8
CT of the lumbar spine 6 0.018 0.7
Chest radiograph 0.02‡ 0.016 0.7
Thyroid uptake 1.9 0.016 0.7
Intravenous urography 3 0.014 0.6
CT of the neck 3 0.014 0.6
Cardiac resting ventriculography 7.8 0.014 0.6

 

For more information on radiation exposure, please visit the National Imaging Associates Web site at www.radmd.com.

Other Resources

 

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* New England Journal of Medicine, "Exposure to Low-Dose Ionizing Radiation from Medical Procedures", August 27, 2009; Vol 361, No. 9, Reza Fazel, M.D., M.Sc., Harlan M. Krumholz, M.D., S.M., Yongfei Wang, M.S., Joseph S. Ross, M.D., Jersey Chen, M.D., M.P.H., Henry H. Ting, M.D., M.B.A., Nilay D. Shah, Ph.D., Khurram Nasir, M.D., M.P.H., Andrew J. Einstein, M.D., Ph.D., and Brahmajee K. Nallamothu, M.D., M.P.H.
** Average effective doses for these imaging procedures are based on data from Mettler et al.
† Calculation of the average radiation dose for myocardial perfusion imaging with the use of single-photon-emission CT relied on dose coefficients from a detailed review of radiation dosimetry of specific cardiac radiopharmaceuticals, median injected radiopharmaceutical doses (millicuries) from the guidelines of the American Society of Nuclear Cardiology, and distributions of the use of various protocols in the United States.
‡ This dose is the effective dose for a posteroanterior study of the chest.
Last updated on 3/7/2018

 

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