While the harmful effects of ionizing radiation have been common knowledge for some time, it is only in the last decade or so that there has been a heavy focus on patient safety in radiology. Unfortunately, this was largely because of heavily reported cases of patients suffering physical trauma due to being excessively dosed during computed tomography (CT) examinations. National organizations such as the American College of Radiology (ACR), Medical Imaging and Technology Alliance (MITA) and the Joint Commission have devised various standards related to radiation safety, but much of the progress of the last 10 years can be attributed to the efforts of individual states, which are in turn inspiring others to take action.
California Leads the Way
The current dose management movement began in California, when a 2009 Los Angeles Times story revealed that 206 patients who had received CT brain scans at Cedars Sinai Medical Center in Los Angeles had been dosed beyond recommended limits, suffering hair loss and radiation burns.1 The story quickly spread to media outlets across the country, forcing the state to act to rectify the situation.
In response, the state legislature introduced SB 1237 in 2010 to mandate better radiation dose monitoring for CT scans. The law, which went into effect July 1, 2012, had numerous components:
• Hospitals and clinics are required to record the dose of every procedure performed on a CT scanner, specifically the dose length product (DLP) and volume CT dose index (CTDIvol);
• When possible, dose information must be sent directly to the picture archiving and communication system (PACS);
• The dose information must also be included in the patient report to help determine their cumulative lifetime radiation dose;
• Facilities are required to report events where patients received excessive dose to the California Department of Public Health (CDPH); and
• Dose levels must be verified annually by a radiation physicist.
SB 1237 was quickly followed by AB 510, which was signed into law by Gov. Jerry Brown just two weeks after the first law took effect. AB 510 clarified several provisions of SB 1237, namely:
• Dose reporting is only required for specific diagnostic CT procedures; and
• Event reporting is only required when the body part that was irradiated is different than the one intended to be scanned.
Texas Follows Suit
While California was drafting its dose management legislation, radiology directors in Texas were watching the process closely. The nation’s second-most populated state has a large number of radiation control program directors and is heavily active in the Conference of Radiation Control Program Directors (CRCPD), according to Lisa Bruedigan, R.T.(R)(M), manager of the Texas Department of State Health Services X-ray inspection group. As a result, it became the second state to adopt radiation dose reporting legislation when Texas Administrative Code Rule §289.227 went into effect May 1, 2013.
The rule is similar to SB 1237 in California, except the Texas version applies to fluoroscopy procedures as well as CT. The actual patient dose does not need to be calculated, but the radiologist is responsible for maintaining a record of the dose output information and using that information to estimate the dose.2
Providers are also required to establish a radiation protocol committee that meets no less than once every 14 months and consists of the following members:
• A radiologist or radiation oncologist;
• A licensed medical physicist;
• A radiation safety officer; and
• Other individuals as deemed necessary by
In addition to monitoring dose protocols, the radiation safety committees are responsible for notifying physicians and patients when an overdosing event occurs; the committee has the authority to decide when notification is required.
Are State Laws Helping?
While laws like those propagated in California and Texas bring dose information to the attention of providers, even supporters of such measures admit their impact is somewhat limited. “It really is just an informational value for most of these facilities,” said Bruedigan, adding that dose information does help retroactively assess protocols when there are problems.
The main element preventing these dose monitoring regulations from being more effective is that the level of technology varies greatly between facilities. Many of the older-model CT scanners do not have direct PACS transfer or dose recording capabilities, making it extremely difficult to establish universal regulations.
Although progress has been limited in turning the reported information into tangible dose reductions, Bruedigan said the training component of the Texas rule has yielded positive results. She noted that many facilities now provide in-house training courses to satisfy the requirement. “We’ve even had some exempt radiologists that took the training on their own and said they learned something,” she said.
Challenges of Dose Reporting
While these state efforts provide a sense of dose output, their usefulness is somewhat limited due to the nature of the information they collect. Dose indices such as DLP and CTDIvol do not measure actual scanner output but are based on use with phantoms. As a result, dose reference levels (DRLs, the 75th percentile of dose distribution) and acceptable doses (ADs, the 50th percentile of dose distribution) drawn from these numbers are similarly limited.
A new paper published in the online version of the journal Radiology looked to address this well-known problem to establish national dose levels for common adult CT exams using actual patient data. The resulting two-year effort was able to determine DRLs and ADs for the 10 most common head, neck and body exams based on patient size using actual patient dose data from the more than 30 million exams in the ACR Dose Index Registry.
“Both ADs and DRLs are provided to encourage facilities to optimize dose to a lower level than that indicated by the DRL,” said Kampana Kanal, Ph.D., a medical physicist, professor and section chief in diagnostic physics in the Department of Radiology at the University of Washington School of Medicine, Seattle. “Image quality must be taken into consideration when using DRLs and ADs to evaluate CT protocols on each scanner to determine if protocols are optimized.”
Connecticut Offers Glimpse of the Future
The end goal of the efforts in California and Texas as well as the ACR DIR is for radiology providers to be able to see and share where their dose levels are to keep providers accountable. Various challenges currently prevent either state from developing a practical mechanism for disseminating this data, but a new project underway in Connecticut may offer a preview of how to move forward.
The Connecticut Hospital Association (CHA), which oversees 27 critical-access hospitals across the state, announced in March it is establishing the nation’s first statewide radiation dose management repository with the help of Bayer.
Several of CHA’s members participate in the ACR DIR, and the national database has provided good insight, according to Mary Cooper, M.D., the organization’s director of clinical services. The drawback, however, is that the CHA does not then own its own data and so can conduct investigations only as far as the ACR will allow. This was the driving force behind the state dose repository, according to Cooper. “The ability to craft a dose repository where everybody wants to participate is great,” she said.
The dose repository is not the first attempt at broader radiation dose monitoring in Connecticut: The state legislature introduced its own dose reporting law, Raised Bill 6423, in 2013, but the measure stalled in committee before it even went to a vote.3
The dose repository project was initiated approximately two-and-a-half years ago by the CHA board of directors. CHA has been collecting patient-level data from its member hospitals since the mid ‘80s, according to Cooper, providing a template for a more active effort. Senior leadership collaborated with radiologists, physicists and imaging directors from across the association to look at the ACR DIR and similar models from other countries. The radiologists in the group recommended limiting the repository to CT only for the time being, and the first hospital was hooked into the system last fall. Cooper said that a total of 12 hospitals are currently patched into the repository. Dose data is taken directly from the CT scanner via Bayer’s Radimetrics Enterprise Platform and flowed to the CHA repository via virtual private network (VPN). Over 130,000 CT scans have been contributed since the first hospital went online.
“The first goal is to define what is appropriate imaging and appropriate dose,” said Cooper, through both retrospective and current data. At present the data is simply being collected — no dose reports are being sent back out to member hospitals or referring providers. “That’s goal No. 2,” Cooper said. Eventually she would like providers to be able to share this information with patients to encourage shared decision-making and empower patients to take control of their own healthcare.
Cooper explained that the reaction to the repository has been “totally positive” across all levels of the CHA, from the board of directors down to individual hospital staff. Having experienced early success, the organization has begun reaching out to ambulatory imaging centers to try to expand participation. Cooper said she could even envision CHA connecting its repository to similar systems in other states, should they undertake such efforts, to develop a shared regional system. Other expansion plans include adding dose monitoring for fluoroscopy and other imaging exams, though at present there is no timetable for such changes.
“It’s very exciting to be the first in this endeavor,” Cooper concluded.
1. Zarembo, A. “Hospital error leads to radiation overdoses,” Los Angeles Times. Oct. 13, 2009. http://articles.latimes.com/2009/oct/13/local/me-cedars13
2. 25 Texas Administrative Code §289.227, “Use of Radiation Machines in the Healing Arts”
3. Steere, A. “Dialing Down Dose: Radiation Tracking and Reporting Tools,” Molecular Imaging. March 5, 2014. Accessed May 8, 2017. http://www.molecularimaging.net/topics/practice-management/quality/diali...