Radiation in Clinical Care

 

Medical Intensive care unit (MICU) patients are exposed to radiation [Cumulative Effective dose (CED)] higher than annual US Federal occupational standard limits  (CED≥50 mSv) within a short period of time due to radiological studies. A study conducted between January and December 2013 found this to be true among 3% of the total 4155 patients > age 18 involved in the study. In 1%, the CED was higher than 100 mSv, which is the Federal cumulative limit for 5 years.

The millisievert (mSv) is a measure of the organic effect of ionizing radiation and is referred to as the effective dose (ED). Statistical tests conducted on the data obtained in the study showed that 36% of the patients were exposed to radiation higher than the natural background radiation (~3 mSv). Values just 3-5 times higher have been suspected to cause carcinogenesis, although the debate is still ongoing.

Ionizing radiation can lead to cancers by damaging our DNA or RNA and causing genetic abnormalities.This is especially true for kids and young adults who have a high rate of cellular division and a longer lifespan to express the effects of radiation.

Radiation is used in numerous reliable diagnostic procedures in the MICU. Although this has been overshadowing the potential risk of cancers, of late, more medical literatures are exploring its adverse effects. The study also showed an increase in the CED for patients with a higher length of stay at the MICU. Diagnosis of sepsis, COPD, cirrhosis and Gastrointestinal bleeding were also seen to affect CED. Among the radiation based Imaging systems used in healthcare, CT and IR caused the highest amount of radiation burden.

radiation burden data distribution
Figure 1 shows the distribution of data obtained by Krishnan et al for radiation burden

Krishnan et al report that despite their adoption of the ALARA (‘as low as reasonably achievable’) principle of radiation safety, patients were exposed to substantial amounts of radiation during diagnosis. They suggest that:

“Proactive monitoring of CED with real time display in electronic medical resorts will assist physicians in deciding the risk-benefit ratio.”

The study was limited in that it was conducted among MICU patients from a single academic medical center. The estimate of ED from previously published papers and the limited medical record systems accessed to obtain the data could have caused an undervaluation of the CED. Another shortcoming was the disregard for patient characteristics like age and sex. However, the results of the study denote a need to conduct significant more research on the effects of radiology in medicine and its pros and cons for overall patient health.

This leaves us with the question, are we so highly dependent on radiological resources that we fail to consider the harm it might be doing? At this day and age of technological advances, there should be more active endeavors to explore the benefits and subsequent disadvantages of radiation in the medical industry.

Reference: Krishnan S, Moghekar A, Duggal A, Yella J, Narechania S, Ramachandran V, Mehta A, Adhi F, Vijayan AKC, Han X, Dong F, Martin C III, Guzman J, Radiation Exposure in the Medical Intensive Care Unit- Predictors and Characteristics, CHEST (2018), doi: 10. 1016/ j.chest.2018/01/019.

Link to article

Canadian Light Source Research Office

 

One Reply to “Radiation in Clinical Care”

  1. I appreciated the clinical relevancy of this article, and especially the question you posed at the end about whether or not a clinical dependence on radiation for diagnostic testing is skewing the medical professionals’ perception of benefit vs harm to a patient. I also liked the graph in the middle because it gave a more practical sense of where the radiation is coming from in a treatment or diagnostic scenario.

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