Methods

In recent times, the method of computed topographic scans (CT scan) is very much used in medical sectors in order to detect various critical diseases. In economically developed countries, CT scan is counted as an effective diagnostic tool. However, the developing countries are not very much far behind. CT scan is an upgraded technique in which computers and x-ray is used to take cross sectional images of the body. In this imaging technique, cross sectional images of the bones, blood vessels, soft tissues can be taken. The images taken by x-ray technique from various angles, can be combined to produce a 3-D image of the particular organ of the body (Victor & Premanathan, 2013). In case of CT scan, the chances of getting exposed to a radiation is higher than that of the x-ray imaging. Multiple CT scan can enhance the chances of cancer. In case of children, this chances are much higher. Along with enhanced use of CT scan in medical diagnosis, the risk of cancer among the patients who are exposed to CT scan, has also come into play. From a study it was seen that, 48% of total radiation exposure is occurred due to the medical imaging techniques such as CT scan. From a report of United States, it was seen that, 0.9% of cancer cases was diagnosed due medical imaging and in recent times this number is much higher than that of the previous (Redberg  & Smith-Bindman ,2014). Therefore , it can be said that, radiation exposure due to CT scan can cause malignancy or cancer among the exposed patients, especially in children. In this report, the consequences of the radiation exposure due to CT scan is discussed. Along with this, the chances of cancer due to exposure to CT scan radiation is also highlighted. 

Methods of Review

1.  Sodickson, A., Baeyens, P. F., Andriole, K. P., Prevedello, L.M., Nawfel, R. D., Hanson, R., Khorasani, R. (2009). Recurrent CT, Cumulative Radiation Exposure, and Associated Radiation-induced Cancer Risks from CT of Adults. Retrieved November 6, 2018, from https://doi.org/10.1148/radiol.2511081296

As this article has enough information from a cohort study to support the chosen topic that is why this article has been chosen.

1. Miglioretti DL, Johnson E, Williams A, et al. The Use of Computed Tomography in Pediatrics and the Associated Radiation Exposure and Estimated Cancer Risk. JAMA Pediatr. 2013;167(8):700–707. doi:10.1001/jamapediatrics.2013.311

In this report, the cohort study report of children ( age group of 5-14 years) who had exposed to CT scan radiation has described. Along with this, the possibility of getting affected by cancer due to gradually increased exposure is also highlighted.

1. Mathews John D, Forsythe Anna V, Brady Zoe, Butler Martin W, Goergen Stacy K, Byrnes Graham B et al. Cancer risk in 680 000 people exposed to computed tomography scans in childhood or adolescence: data linkage study of 11 million Australians BMJ 2013; 346 :f2360

This article has been chosen as this article concentrated on the fact that, irradiation may cause cancer. However, CT scan is helping in diagnosing various diseases, it has prominent adverse effect. So it should be used in a very restricted manner and only should be used when there is an actual need of the CT scan diagnosis.

1. Albert, J. M. (2013). Radiation risk from CT: implications for cancer screening. American Journal of Roentgenology, 201(1), W81-W87. Retrieved from:  https://www.ajronline.org/doi/abs/10.2214/AJR.12.9226.

This article has been chosen as this article evaluated the risk of getting affected by cancer due to exposure of CT scan. The data suggested that, there was serious risk of developing malignancy from the CT scan radiation. Along with this, the benefits of CT scan for screening of caner is also discussed.

1. 5. Moorin, R. E., Gibson, D. A., Forsyth, R. K., & Fox, R. (2014). Demonstration of the effect of generic anatomical divisions versus clinical protocols on computed tomography dose estimates and risk burden. PloS one, 9(5), e97691. doi:10.1371/journal.pone.0097691

This study concludes that modern CT scanning procedures pose a diverse effective dose than most studies describe adding that a lack of focus on scanning protocols has the tendency of producing estimates that do not reflect the range and complexity of modern CT practice. 

1. Walsh, L., Shore, R., Auvinen, A., Jung, T., & Wakeford, R. (2014). Risks from CT scans—what do recent studies tell us?. Journal of Radiological Protection, 34(1), E1.

Discussion

As this article has enough information from a cohort study to support the chosen topic, that is why this article has been chosen.

1. Seal, A., Hawkes, M., Bhargava, R., Noga, M., Preiksaitis, J., Mabilangan, C., & Robinson, J. (2017). Radiation Exposure from Diagnostic Imaging in a Cohort of Pediatric Transplant Recipients. PloS one, 12(1), e0167922. doi:10.1371/journal.pone.0167922

In this study, the radiation exposure from the medical imaging was discussed. Along with CT scan, other medical imaging techniques like radiation due to x-ray is also described. This fact supported the statements of other resources as well.

According to the study of Sodickson et al. (2009), the study comprised of 31462 patients who had experienced CT scan as part of their diagnosis in 2007 and they had also undergone 190 712 CT examinations in last 22 years. As per this study result, 15% patients had received doses of > 100 mSv and 4% of the total patients had received doses in between 250 -1375 mSv. From this study they had estimated that, CT exposure caused approximately induced cancer among 0.7% total patients and 1% of total cancer mortality was induced. They concluded that, exposure of CT radiation enhanced the risk of baseline cancer among the cohorts. However the risk of radiation induced cancer was low among most of the patients, but a particular subgroup had higher risk due to CT imaging.  The ionizing radiation can be absorbed by the DNA in the human body and as a result DNA can be damaged due to this. The radiation induced malignancy is a random process and it is assumed that, the risk is increasing due to exponential dose of radiation. The damaged DNA is associated with the oncogenic mutation that is responsible for the onset of cancer in the human body. The doses more than 100mSv was thought be very risky and this supported the study of Sodickson et.al (2009). In a study done by an International Agency for Research on Cancer showed that, risk of cancer mortality rate was 0.97 per sievert among 400,000 nuclear industry worker who were exposed to dose of 20mSv radiation (Albert, 2013). A study by Mathews et al. (2013) depicted the risk of cancer in the children and adolescent population who had already exposed to the ionizing radiation during the CT scan. In this study, 10.9 million of Australian population was selected as cohort who were under the age group of 0-19 years on 1^st January, 1985 or in between 1^st January, 1985 to 31^st December, 2005. From their result it was seen that, overall cancer incidence was 24% higher for the exposed individuals than that of the unexposed one. Almost 60,674 cancer cases were reported and among them 3150 in 680,211 people had exposed to CT radiation. They had also estimated that, the effective radiation dose per scans was 4.5mSv. They also reported about the more 608 cancer patients who were exposed to CT scans. They had concluded that, the enhanced risk of cancer by CT exposure among the cohort was because of the irradiation. The study of Miglioretti et al. (2013) also highlighted the fact of radiation exposure due to CT scan among the children. In this study, the children under the age of 15 years from 1996 to 2010 was selected as cohort. In this study they had used the doses that were varied from 0.03 to 69.2 mSv. Moreover, dose of 20mSv or more was applied to 24-25% of abdomen pelvis scans, 3-8% of chest scans and 6-14% of spine scans. The projected lifetime risks of cancer were higher among the girls and younger people than that of the boys and older patients. In addition it was seen that the patient who had pelvic or abdomen scan had the higher chances of getting affected by cancer than the patients who had other type of scans. In case of girls,  a radiation induced cancer was found from every 300-390 abdominal/ pelvic scan cases, 270-800 from spine scan cases and 330-480 from chest scan cases. It was discovered that, among the children ( age > 5 years) the risk of leukemia was about 1.9 cases per 10,000 CT scan cases ( specifically head scan). The study of Moorin et al. ( 2014) supported the organ specific induction of cancer due to exposure of CT scan radiation. In their study, they had identified various techniques of CT scan and along with this, doses were also identified to assess the difference among various techniques of CT scan.  Their study had enlighten the fact that abdominal scan protocol had the highest risk of inducing cancer. The estimation using the mean dose of anatomical scan showed that, the incident of cancer cases were 86 and the mortality rate was 69. However, while actual protocol was used the estimation was enhanced and it became almost 214 cases of cancer patients and almost 138 cases of cancer related deaths were found after using actual protocol. So it can be said that, the actual protocol and the area of CT scan are very much related to the effective radiation dose and related incidents of cancer. The patients who had a solid organ transplantation (SOT) were regularly exposed to the diagnostic imaging (DI) and they were under high risk zone of having a cancer. In this study, they had tried to measure the exposure among the patients. Children of North Alberta who had have SOT at Sollery Children’s Hospital were selected as the study population. Children under the age group of 5 years underwent more DI studies than that of the older children. The risk of malignancy was increased by exposure to radiation and it was estimated that 1% of total malignancies in US and Canada were due to the radiation from Diagnostic imaging. Along with this, the life time excess risk of death due to cancer was assumed almost 0.4% while the patients were exposed to 100mSv of radiation. In addition, it was seen that, the effective dose of radiation for the head CT scans was 2.68mSv and for the abdomen region it was estimated about 5.06mSv. In this study, the ultimate number of cohort was 54 children (24 males and 30 females). From this study it was found that, the 1 out of 3 children had been suffering from cumulative dose of radiation above the level of 100mSv. A study conducted on the 202 heart transplanted patients showed that in post-transplant condition, 84mSv was the effective dose for radiation exposure. In case of adults the increased mean dose of radiation exposure, enhanced the risk of cancer by 0.55% (Nguyen, Patel & Weng, 2013).  The study of the Hsu et al. (2013) also supported that, the risk of CT scan induced malignancy was highest among the children who had exposed to radiation at a very younger age.

Conclusion 

In this report, the risk of CT scan induced malignancy is discussed. This report showed that, the chances of affected by cancer is very much high among the children who are exposed to radiation at their very younger ages. Along with this, role   dose specificity in onset of malignancy is also highlighted. In order to reduce the malignancy induced by the CT scan various methods can be introduced such as using of exact protocol, using of standardized dose of radiation, minimal use of CT scan diagnosis. It is highly recommend that, the CT scan diagnosis should be only used in extreme cases. In addition to this, the health care provider should be educated about the adverse effect of CT scan radiation. Lastly, it can be said that using of CT scan is ultimately enhancing the rate of cancer risks among the patients.   

References

Albert, J. M. (2013). Radiation risk from CT: implications for cancer screening. American Journal of Roentgenology, 201(1), W81-W87. Retrieved from:  https://www.ajronline.org/doi/abs/10.2214/AJR.12.9226.

Hsu W L et al. (2013) The incidence of leukemia, lymphoma and multiple myeloma among atomic bomb survivors: 1950–2001 Radiat. Res. 179 361–82.

 Mathews John D, Forsythe Anna V, Brady Zoe, Butler Martin W, Goergen Stacy K, Byrnes Graham B et al.(2013) Cancer risk in 680 000 people exposed to computed tomography scans in childhood or adolescence: data linkage study of 11 million Australians BMJ 2013; 346 :f2360

Miglioretti DL, Johnson E, Williams A, et al (2013). The Use of Computed Tomography in Pediatrics and the Associated Radiation Exposure and Estimated Cancer Risk. JAMA Pediatr. 2013;167(8):700–707. doi:10.1001/jamapediatrics.2013.311

Moorin, R. E., Gibson, D. A., Forsyth, R. K., & Fox, R. (2014). Demonstration of the effect of generic anatomical divisions versus clinical protocols on computed tomography dose estimates and risk burden. PloS one, 9(5), e97691. doi:10.1371/journal.pone.0097691

Nguyen, K. N., Patel, A. M., & Weng, F. L. (2013). Ionizing radiation exposure among kidney transplant recipients due to medical imaging during the pretransplant evaluation. Clinical Journal of the American Society of Nephrology, 8(5), 833-839.

 Seal, A., Hawkes, M., Bhargava, R., Noga, M., Preiksaitis, J., Mabilangan, C., & Robinson, J. (2017). Radiation Exposure from Diagnostic Imaging in a Cohort of Pediatric Transplant Recipients. PloS one, 12(1), e0167922. doi:10.1371/journal.pone.0167922

Sodickson, A., Baeyens, P. F., Andriole, K. P., Prevedello, L.M., Nawfel, R. D., Hanson, R., & Khorasani, R. (2009). Recurrent CT, Cumulative Radiation Exposure, and Associated Radiation-induced Cancer Risks from CT of Adults. Retrieved November 6, 2018, from https://doi.org/10.1148/radiol.2511081296

Redberg, R. F., & Smith-Bindman, R. E. B. E. C. C. A. (2014). We are giving ourselves cancer. New York Times, 30(1).

Victor, J., & Premanathan, A. (2013). Virtual 3D planning and patient specific surgical guides for osteotomies around the knee: a feasibility and proof-of-concept study. The bone & joint journal, 95(11_Supple_A), 153-158.

Walsh, L., Shore, R., Auvinen, A., Jung, T., & Wakeford, R. (2014). Risks from CT scans—what do recent studies tell us?. Journal of Radiological Protection, 34(1), E1.