Radiation Dose Safety: Medical Imaging Essentials

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By Neil SinghNeil Singh

As often happens when a subject is hot, the radiation safety information pool has become muddied with disparate and conflicting information. With numerous opinions and interpretations on radiation safety trends, best practices, regulation updates, and studies, healthcare providers as well as the general public are experiencing difficulties filtering the true message in radiation safety away from industry noise. Healthcare providers are constantly reviewing and assessing regulations, best imaging processes, and the emerging technologies (automated dose management systems and dose management CT devices) promising to decrease or eliminate the chance of another Sentinel Event.

A good radiation safety program is multifaceted. Regardless of the implementation of automated radiation dose management systems and devices, a healthcare provider’s radiation safety program must include well established and continuous CT imaging protocol management for adult and pediatric patients, ongoing training/education for all staff members, incident risk management planning, advanced workflows including order decision support, imaging policies and procedure, patient education and communication, and methods in messaging and marketing the program to the community, perhaps even the industry. Patient radiation dose safety has again gained regulatory interest; the Joint Commission  released its 2014 standards  for diagnostic imaging, the Journal of American College of Radiology has released a case study on the risk of using CTDI and DLP as aggregate patient dose management guidelines, and Congress passed H.R. 4302– the Protecting Access to Medicare Act, delaying the Sustainable Growth Rate (SGR) calculations and including radiation safety measures.


The Joint Commission’s Diagnostic Imaging Requirements

There are numerous articles reviewing the 2014 Joint Commission Standards for Diagnostic Imaging; however, there is still confusion on the interpretation of some of the standards. Many articles confuse the reader by incorporating MR standards with radiation safety guidelines. Here, we will simply focus on CT imaging. The facts are these:

  • By July 1, 2015 all individuals performing CT procedures must be American Registry of Radiological Technologist (ARRT) or Nuclear Medicine Technology Certification Board (NMTCB) registered.
  • Healthcare providers must have a robust internal radiation safety program, which includes a strong ongoing education/training component guided by Image Gently® and Image Wisely®.
  • Healthcare providers who provide CT imaging services must report the patient’s radiation dose (CTDI and DLP) information in the diagnostic imaging report as well as make it part of the patient’s medical record.
  • For the elements of performance, healthcare providers must have adult and pediatric CT imaging protocols benchmarked and reviewed annually by a physicist.

The Joint Commission did not state in the requirements that technologists must be registered in CT. The 2014 Standards; however, requires providers to manage the CT device CTDI and DLP radiation dose output. The CTDI and DLP dose values do not reflect the true effective dose or size specific dose estimate(s) (SSDE) for the patient. Healthcare providers seeking effective dose or SSDE values must incorporate the patient size and habitus and other imaging technique variables calculated and validated by a medical physicist.


The JACR: Dose Is Not Always What It Seems

Recently, the Journal of American College of Radiology conducted and released a case study on the accuracy of using CTDI and DLP dose values as an effective method for monitoring patient radiation dose. The study was conducted when a concerned parent of a patient requested the CT dose information from the pre and post procedure CT scans. The dose information was given to the parent without altering the data (true effective or SSDE calculations were not calculated), and with proper instructions or education. The parent’s concern triggered an advanced investigation into the incident and the two different dose outputs received from the procedures. Because the two studies of the same patient and body part were performed on two different CT devices (different manufacturers using two different phantom sizes for dose output calculations), the two scans produced two very different CTDI and DLP values. The JACR study concludes the sole reference to CTDI and DLP dose values, without true calculation of SSDE or effective dose, are not effective or accurate methods in managing a patient’s radiation dose.

The case study confirms the importance of establishing a robust radiation safety program, which is a combination of people, process, and technology. CTDI and DLP dose values are nowhere near close to the effective radiation dose received by the patient. The device and dose calibration to phantom size only controls CT device radiation dose output based on a specified phantom size (16cm or 32cm). The phantom size for patient dose management does not take into account key calculation factors such as weight, body habitus and composition, tube angle, etc., which would determine the true effective dose.

The recent awareness of radiation dose safety has also brought forward automated radiation dose management technologies claiming to minimize or even eliminate another Sentinel Event or radiation overexposure. That may be true; however, these automated solutions do not assist healthcare providers with flawless tools in managing the patient’s aggregate effective dose. Accurately managing patients’ radiation dose is a combination of the right people (physicists, technologists, radiologists, risk management, etc.), the right processes (dose calculation, CT protocol management, risk management, informed decision support, patient and staff education, etc.), and the right technology (updated CT devices with low dose technology, Order Entry Management decision support, automated dose management solution, etc.). Healthcare providers must not solely depend on an automated solution to manage its entire radiation dose safety program.

The JACR’s case study confirmed what physicists knew and feared from the beginning and has placed the imaging community back to starting point in developing a robust internal radiation safety program.


The Protecting Access to Medicare Act

In their effort to delay the activation of the Sustainable Growth Rate (SGR) and the 24 percent cut to Medicare reimbursement associated with the initiative, Congress recently passed the H.R. 4302. The bill delays the SGR by 12 months and includes additional requirements for imaging healthcare providers on radiation safety:

  • Ordering physician decision support for advanced imaging procedure.
  • Improved and stricter patient radiation dose safety controls and levels.
  • CT equipment must meet the National Electrical Manufacturer Association (NEMA) standards.

Supported by the American College of Radiology (ACR), H.R. 4302 reinforces radiation safety standards for organizations dependent on Medicare reimbursement.



Radiation safety will continue to gain traction in the industry. Regulatory entities will continue to refine the standards until they strike a balance of people, process, and technology defining a radiation dose program. Healthcare providers must proactively forge ahead of the emerging trends and regulations in developing a codified, sustainable and comprehensive radiation safety program.



Seibert J, Boone J, Wootton-Gorges S, and Lamba R. Dose Is Not Always What It Seems: Where Very Misleading Values Can Result From Volume CT Dose Index and Dose Length Product. Journal of the American College of Radiology. 2014; 11(3): 233-237. Available at: http://www.jacr.org/article/S1546-1440(13)00663-7/fulltext

The American College of Radiology. House of Representatives Passes 12-Month SGR Patch; Numerous ACR Supported Imaging Provisions Included in Legislation. 2014. Available at: http://www.acr.org/Advocacy/eNews/20140328-Issue/House-of-Representatives-Passes-12-Month-SGR-Patch. Accessed May 13, 2014.

The Joint Commission. Prepublication – Diagnostic Imaging Services Requirements. 2013. Available at: http://www.jointcommission.org/standards_information/prepublication_standards.aspx. Accessed May 13, 2014.


Neil Singh is a senior consultant at Ascendian Healthcare Consulting and a frequent speaker and published contributor to the subject of Enterprise Dose Management and Tracking. You may contact him directly at nsingh@ascendian.com or visit the Ascendian website for more information at www.ascendian.com.

For more regulatory news, visit www.ahraonline.org/news.

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