Overutilization of Radiation Exposure in Imaging Scans, Capstone Project Example

The overutilization of imaging technology in patient diagnosis, particularly computed tomography (CT) scans, is an important medical issue with far-reaching consequences. Indeed, recent studies have revealed elderly Medicare recipients often times receiving two CT scans in one day, a practice with little medical benefit that puts individuals at higher risk for a number of diseases including cancer. This paper will propose that the overuse of CT scans for diagnostic purposes is not only a problem that is widespread throughout the medical community, but it is also a problem that can be addressed through a number of solutions. In particular, greater government regulation of CT scanning, education initiatives for both doctors and patients, and improvements in scanning technology will all help to reduce excess radiation and disease incidence related to CT scan use.

Although medical studies chronicling problems associated with the overuse of radiation imaging, and in particular the use of CT, are not numerous, they present an existing problem that can be changed.  David Brenner and Eric Hall of Columbia University identified over use of CT scans as a dangerous, unaddressed public health threat in the United States.  Indeed, although CT scans are a common diagnostic procedure for a wide range of medical conditions, there are numerous inherent risks in the procedure due to its use of radiation.  In order to understand what risks the use of radiation introduces and estimates the risks to patients, the authors detail that a CT scan can have more than 200 times the radiation of a typical x-ray (Brenner & Hall, 2007). In addition, the authors employ methodology to estimate the risks presented by CT scans: Although the risks introduced on an individual level are rather small (risk of various cancers increases roughly 1-3% in individuals), when applied to the entire population, the increased risk of radiation is noticeable.  According to their model, the authors estimate that 1.5-2.0% of all cancer cases may be attributable to over use of CT scans (Brenner & Hall, 2007). While this percentage is small, when distributed over an increasing population, it represents a substantial public health issue that can be addressed through a number of measures.

There are two primary causes identified in the literature related to patient’s intake of excess radiation via CT scans: 1) Unnecessary diagnostic scans for patients who might not need them; 2) Dangerous levels or radiation given to patients due to a miscalibration of the machine or errors by radiological staff. The use of CT scans is unevenly distributed throughout the population:  Certain patient populations and those in emergency departments are more likely to receive CT scans than others. One of the main sub-populations at risk is children; this is not only because children’s cells replicate at a higher rate than older individuals and are thus at greater risk for radiation poisoning, but for the same reason (faster division of cells) they are also at a higher risk for some cancers.  In order to understand the utilization of CT scans with children, Larson et al. analyzed hospital data from 1985-2008 regarding use of CT scans in pediatric emergency room visit. The researchers found the number of pediatric ED visits that included CT examination increased from 330,000 to 1.65 million over the 23 year time period, a 500% increase (Larson, Johnson, Schnell, Goske, Salisbury, Forman, 2011). The authors pointed out that not only has the absolute number of scans increased, but the ratio has also increased showing that doctors are more willing to use CT scans on children, perhaps without realizing the risks and opportunities to use other diagnostic equipment.

In addition to the overuse of CT scans, errors in use of the CT machinery may also expose patients to unhealthy levels of radiation. Smith-Bindman et al. performed a study in which they tried to assess the level of radiation received by a patient at four medical institutions in San Francisco, California for a routine CT scan. The study’s authors found there was a 13-fold variation between the highest and lowest dose for each CT type a patient could receive at the four medical institutions (Smith-Bindman et.al, 2009).  Overall, the authors were unable to find a discernible pattern in the variance of radiation.  Taking the average estimates obtained from the radiation scans, the authors estimated that 1 in every 270 forty-year- old women undergoing a CT angigogram would likely develop cancer (Smith-Bindman et al., 2009).

After exploring the potential causal mechanisms behind excessive radiation exposure, the issue arises regarding the potential scope of this problem.  While a number of different estimates have emerged regarding the absolute risk CT scans pose to the general population, Berrington de Gonzalez et al. conducted research in order to estimate the potential cancer risks from CT scans performed in the year 2007. The authors estimated the number of different CT scans performed in the US in 2007 via using Medicare claims data and surveys of use across nearly 2,450 facilities in the US.  After correcting for the age and sex distribution in the population, the authors estimated that approximately 72 million CT scans were performed in 2007: The number of CT scans increased with age and were more prevalent for female patients (60%) than male patients (40%).  Overall, the authors estimated that 29,000 future cancer cases would result from the number of CT scans performed in 2007 (Berrington de Gonzálea et. al, 2007).  While the absolute number of cases is quite small compared to the general population of the United States (well below 1 percent), the number is quite substantial when compared to the number of new cancers diagnosed annually: Indeed, there were 1.4 million cases of cancer diagnosed in 2007, the authors estimate is roughly 2% all cancer cases diagnosed in that year. However, one must remember that the new incidence cases is distributed over a wide range of time, in this light, the risks added by CT scans is substantial.

With the origin, causes, and scope of the problem examined, this section will now turn to potential solutions for the situation. There are three primary solutions presented in the literature to address the problem related to overuse of CT scanners: 1) increased education for doctors and patients (focusing on communication between the two); 2) use of different, less powerful scanners; 3) reexamination of cost-benefit analysis of CT scans.  Lee et al. conduct a study gauging knowledge of the radiation levels and risks related to CT scans: The results showed that doctors and individuals both lacked a keen understanding of potential risks with only seven percent of patients knowing the risks associated with CT scans (Lee et al., 2004). With evidence that both doctors and patients could benefit from increased education in the area, Lee et al. posit that doctors more educated about the risks could also communicate them better to patients, who in turn, could make a more informed decision regarding the test.
Brenner and Hall address two other ways that the overuse of CT scans could be mitigated.  First, doctors can often times replace CT scans with alternative diagnostic methods that include ultrasonography and magnetic resource imaging (MRI) (Brenner &Hall, 2007).  Indeed, ultrasonography can be used successfully in the diagnosis of appendicitis, and MRI, while still not cost competitive with CT scans, is being explored as another means to prevent excess radiation.  Finally, clinicians would be well served reexamining when CT scans are truly necessary and when they are practiced merely as a function of defensive medication.  As Brenner and Lee (2007) state, in situations where patients truly need a CT scan, the diagnostic information gained from the CT scan far outweighs the risks involved.  However, if nearly 33% of CT scans currently performed are not needed, there is a robust area for further examination.

While the overuse of CT scans, and medical studies detailing the problem, are still in a nascent phase, this area is fecund for further research.  Indeed, the risks associated with excess CT scans presents palpable risks to children and adults alike in the form of excess radiation.  At the same time, unlike many medical problems, the solution set for this problem can be implemented at numerous points to reduce both supply and demand. Efforts to better education doctors and patients, the use of new equipment emitting less radiation, and a further review of existing practices can help ameliorate the problem.

References

Baumann, B.M., Chen, E.H., Mills, A.M., Glaspey, L.G., Thompson, N.M., Jones, M.J., Farner, M.C. (2011).  Patient perceptions of computed tomographic imaging and their understanding of radiation risk and exposure.  Annals of Emergency Medicine. 58(1), 1-7.

Berrington de González A, Mahesh M, Kim K-P; et al (2009). Projected cancer risks from computed tomographic scans performed in the United States in 2007.Archives of Internal Medicine, 169(22), 2071-2077.

Brenner, D & Hall, E (2007).  Computed Tomography- An Increasing Source of Radiation Exposure. New England Journal of Medicine.  357 2277-2284.

Larson, D.B., Johnson, L.W., Schnell, B.M., Goske, M.J., Salisbury, S.R., Forman, H.P. (2011).  Rising use of CT in Child Visits to the Emergency Department in the United States 1995-2008. Radiology.  259(3), 793-801.

Lee, C.I., Haims, A.H., Monico, E.P., Brink, J.A. & Forman, H.A. (2004).   Diagnostic CT scans: assessment of patient, physician, and radiologist awareness of radiation dose and possible risks.  231 (2), 393-398.

Smith-Bindman R, Lipson J, Marcus R, et al. (2009). Radiation dose associated with common computed tomography examinations and the associated lifetime attributable risk of cancer. Archives of Internal Medicine. 169 (22), 2078–86.