Patient Safety Tip of the Week
February 2, 2010 The Hazards of Radiation
In our October 20, 2009 Patient Safety Tip of the Week “Radiology Again…But This Time It’s Really Radiology!” we discussed the FDA safety alert that had been issued after a large number of radiation overdoses occurring at Cedars-Sinai from CT brain perfusion imaging studies. Ultimately, the FDA found 250 such cases at Cedars-Sinai and also found similar cases at multiple other hospitals and in multiple states (AuntMinnie.com Dec.7, 2009). More than one type of CT scanner was also involved. Victims of the radiation overdoses suffered primarily hair loss and cutaneous damage but the potential long term effects remain speculative. The occurrence was a wakeup call for hospitals and diagnostic facilities to put in place more rigorous safeguards in developing imaging protocols and better monitoring of radiation dosages actually administered.
As alarming as the CT incidents were, they pale in comparison to some of the incidents due to radiation therapy that were revealed last week in a 2-part series in the New York Times. Walt Bogdanich and colleagues (Bogdanich 2010a and 2010b) did an amazing job researching this revealing series, going far beyond what most investigative and regulatory bodies could have done.
Though both ASTRO (American Society for Radiation Oncology) and AAPM (American Association of Physicists in Medicine) were quick to issue statements pointing out the relative rarity of serious errors in radiation therapy and the unquestioned significant benefits that patients may get from radiation therapy, they missed some of the key messages in the NYT series.
The NYT series begins with some very graphic and sad
descriptions of suffering and death related to radiation therapy overdoses
resulting from errors. That, of course, is a technique we strongly recommend in
patient safety (see our December 2009 What’s New in the Patient Safety World
column “Stories,
Not Statistics”). But those are just to get your attention. The real gist
of the series is that radiation therapy errors are probably considerably more
common than we are led to believe and that the remarkably fast pace of advances
in radiation oncology are outstripping our ability to implement adequate
safeguards. Hospitals and outpatient facilities, in their haste to get the
latest and greatest technology, often underestimate and underresource all the
other things needed for a safe implementation. Ensuring that all relevant staff
are adequately trained and understand the new technology often takes a back
seat to marketing the new technology and getting it started.
Striking in the NYT series is the delay that often occurs before facilities recognize that an error has occurred and that multiple patients may be affected before corrective action is taken. Since the effects of radiation damage may be delayed, it is not surprising that such lapses in recognition may occur. More importantly, they noted that many facilities have no outcome monitoring in place – neither measuring their successes nor their complications! The NYT authors interviewed an impressive array of radiation therapy experts in putting together this series. Failure rates with some of the newer technologies are often striking. One interviewee noted that among hospitals seeking participation in a clinical trial, 30% failed to accurately radiate a phantom object. They pointed out that a variety of relatively inexpensive independent evaluators of radiation therapy programs are seldom used.
Grossly understated in the NYT series is the economic incentives driving much of the boom in advanced radiation oncology procedures and techniques. The NYT series does acknowledge that some hospitals and facilities, in attempt to capture part of the oncology market, have implemented technologies like IMRT with inadequate training of all relevant staff and software having many glitches. Frankly, the reimbursement and profitability for IMRT outstrips more conventional external beam radiation therapy many times over. Financial motives clearly are one of the root causes of this problem.
Ironically, the Pennsylvania Patient Safety Authority had done a nice article on Errors in Radiation Therapy in September 2009. While pointing out that such errors are rare, the PPSA acknowledged that devastating and fatal injuries may result from errors in radiation therapy. They describe radiation therapy as a complex and high risk procedure involving a large number of steps and medical staff. Any process or procedure with so many steps and personnel involved inevitably is associated with errors that may lead to poor outcomes. Not only may such errors result in radiation damage to tissue but others may result in undertreatment of cancer or other condition being treated.
Over a period of about four and a half years, the PPSA received only 25 reports of radiation oncology events. Most were near misses and only 6 involved serious injury. Leading categories of event were a patient receiving the wrong dose of radiation (40%), wrong patient (16%), wrong location radiated (12%), wrong side (12%) and wrong setup (8%). They also report similar problems reported to the Pennsylvania Department of Environmental Protection and a voluntary web-based database of radiation therapy events maintained by the Radiation Oncology Safety Information System.
The real value of the PPSA article is in the risk reduction strategies recommended. Given that patient identification and laterality issues comprised a significant portion of the events in their database, it is no surprise they recommend focus on patient identification. The point out that Joint Commission excludes radiation oncology from the Universal Protocol standard. However, they recommend that radiation therapy staff perform a final verification, including 2-identifier verification of patient identity, site of treatment, laterality (including comparison to films and images), and comparison to the consent and treatment plan.
They also recommend checking the radiation therapy treatment plan and performing an independent recheck before the patient receives the prescribed dose of radiation. They point to an Australian study (Duggan et al 1997) that showed independent double checks resulted in changes to treatment plans in about 10% of cases, though a substantial increase in staffing is required to carry these out.
They have an excellent discussion on the use of computer technology for treatment plans and discuss the computerized record and verification (RV) system that most linear accelerators have. They acknowledge that, though RV systems have significantly reduced the number of errors in radiation therapy, they have introduced new types of errors and many facilities and staff have become overreliant on the computer systems. Moreover, human errors during manual entry into RV systems may be propogated to multiple patients. They also acknowledge that errors in computer programs are generally much more difficult to detect than those in manual systems.
They also recommend in vivo densitometry as a reliable method for verification of external beam therapy. This refers to dose measurements taken on patients during the delivery of radiation therapy.
The PPSA article attributes the rarity of errors in radiation therapy to the “strict regulatory environment”, stating that it is considered to be one of the most highly regulated medical practices. The NYT series certainly blows holes in that perception! The NYT authors noted numerous examples of significant incidents avoiding oversight because of split regulatory authority, such that neither agency had oversight capability and numerous other deficiencies in regulatory oversight. The bottom line: even though the published rates for radiation therapy errors are on the order of 1 in 1000 cases, no one really knows what the real error rate is.
Despite the alarming nature of this week’s column, we also do have some positive news as well. In our October 20, 2009 Patient Safety Tip of the Week “Radiology Again…But This Time It’s Really Radiology!” we made a case that facilities should attempt to track cumulative doses of radiation (particularly for radiation in diagnostic imaging). In fact, one such healthcare system has begun to do exactly that. The Lifespan Health Network in Rhode Island has added software that keeps track of previous CT scans done at any of its member hospitals. If a physician then orders a new CT scan the software looks at the prior cumulative radiation dose and, if appropriate, may warn the ordering physician that the patient has already received a relatively high radiation dosage in the past. This may result in the physician considering alternative imaging techniques that may not use radiation. Ultimately as health systems develop longitudinal electronic medical records or RHIO’s accumulate medical records from multiple sources and patients have their own electronic personal health records, we expect that such software algorithms would track cumulative radiation doses much more accurately.
References:
FDA finds new cases of CT radiation overexposure
By Brian Casey
AuntMinnie.com staff writer
December 7, 2009
http://www.auntminnie.com/index.asp?Sec=sup&Sub=cto&Pag=dis&ItemId=88721
Bogdanich W. The Radiation Boom. Radiation Offers New Cures, and Ways to Do Harm. New York Times. January 24, 2010
http://www.nytimes.com/2010/01/24/health/24radiation.html
Bogdanich W. The Radiation Boom. As Technology Surges, Radiation Safeguards Lag.
The New York Times. January 26, 2010
http://www.nytimes.com/2010/01/27/us/27radiation.html
Williams TR. Radiation therapy 99.99 percent safe and effective (ASTRO Letter to NY Times). January 25, 2010
AAPM. AAPM Statement on Quality Radiation Therapy. January 2010
http://www.aapm.org/publicgeneral/QualityRadiationTherapy.asp
Pennsylvania Patient Safety Authority. Errors in Radiation
Therapy
Pa Patient Saf Advis 2009 Sep;6(3):87-92. http://www.patientsafetyauthority.org/ADVISORIES/AdvisoryLibrary/2009/Sep6%283%29/Pages/87.aspx
Duggan L, Kron T, Howlett S, et al. An independent check of
treatment plan, prescription and dose calculation as a QA procedure.
Radiother Oncol 1997; 42(3): 297-301
Ridley EL. Software offers alerts for patients with past CT scans. AuntMinnie.com January 28, 2010
http://www.auntminnie.com/index.asp?Sec=sup&Sub=ris&Pag=dis&ItemId=89255
http://www.patientsafetysolutions.com
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