A Dissection of Computed Tomographic Angiography (Research Paper Sample)

Diagnosis of Coronary arterial disease as a contributing factor to cancer: A dissection of Computed Tomographic Angiography
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Diagnosis of Coronary arterial disease as a contributing factor to cancer: A dissection of Computed Tomographic Angiography
Introduction
There has been a tremendous shift towards use of computed tomographic angiography in diagnosing coronary arterial disease; in the recent years. The technology of Computed Tomographic Angiography has also significantly advanced in different stages since its advent. In a bid to enhance the applicability of non-invasive computed tomographic angiography, scientific developments have come up with wide area detector Computed Tomographic systems and perfusion imaging (Kitagawa K, Lardo A, Lima J, George T; 2009). Therefore the 64-row detector is now obsolete and has been replaced by the 320-row Computed Tomographic system which has the ability to sustainably allow the applicability of ECG gating when it comes to Computed Tomographic Angiography. The ultimate implication of all these is that the image quality has greatly improved, paving way for more accurate test scans.
Bearing in mind the fact that CT Angiography is now the most conventional model of diagnosing coronary disease, it is alarming that the technology does not guarantee absolute safety of the patients. Computed Tomographic Angiography is associated with increased radiation doses over and above the normal or conventional radiography conducted regularly like the x-ray. With a clear disparity in the radiation doses offered across the world depending on the nature of the CT Study, it is hard to discern the precise content of radiology that can be directed towards one patient. The fact which has been agreed upon however is the fact that according to scientific research, radiation waves if applied to a certain extent may lead to the patient contracting cancer (Steigner M, Otero H, Cai T; 2009). Therefore it interests me to investigate further the viability of Computed Tomographic Angiography in this cancerous age, where there is no much information about the amount of radiation dose that may lead to one getting cancer.
Background
In the wake of numerous CT examinations performed yearly across the world; and the positive contributions that the technology has had on the welfare of patients, it is hard to criticize the probative value of Computed Tomographic Angiography at present. However, this does not mean that the method is wholesomely infallible. Here is a detailed analysis of salient developments in the technology of CT Angiography.
CTA vis-à-vis Radiation dose
A study conducted in the Unites States in 2006 indicates that from 1986, there had been a 10% yearly increase of CT imaging studies (National Council on Radiation Protection and Measurements, 2009). Diagnostic medical radiation alone had released a collective dose increase of around 700% in terms of radiography and nuclear medicine studies. Even though it was also noted that 80% of the studies were conducted on a potentially at risk population of patients; most of them severely ill and elderly, it is noteworthy that the radiation dose that is emitted during CT Angiography is in large quantities and thus its ramifications have to be equally examined.
Medical Radiation as a Cause of Cancer
While it has never been disputed that indeed the Computed Tomographic Angiography’s usage leads to massive radiation emissions, what has never been conventionally agreed on is the extent to which the radiation waves may contribute to patients getting cancer. There has been no study to indicate the dose response relationship with respect to this phenomenon. Therefore, the assumption which is prevalent in the medical world is that even the least amount of radiation dose is capable of causing malignancies (McCollough 2008). The quantum of risk associated with each emission is dependent both proportionally and linearly on the amount of the dose.
The Ideal contribution of Radiation towards contracting cancer
There is still no definite way of discerning the number of CT scans which would ultimately result in a cancer. This uncertainty is occasioned by a number of other extraneous factors like age, sex and the nature of the study; which heavily influence the resistance of a patient to being exposed to radiation. A summary of research on this subject indicates that in general, women are more vulnerable to cancer resulting from CT Angiography examinations than men. Young people are also more likely to be exposed to a higher radiation dose than old people and thus, may easily be affected by cancer as a result of this process (Shuman W, Branch K, May J, et al. 2009). Finally, it is also the position of recent research that normal Computed Tomographic Angiography head scan is much safer than a Coronary CT Angiography as regards the susceptibility to getting cancer. Bearing this in mind it is therefore logical to conclude that either way, regardless of all the aforementioned factors, radiation resulting from CT Angiography has the potential to cause cancer if applied to any person of any gender, at any gender and on any study (Einstein A, Henzlova M, Rajagopalan S; 2010)
The Dose Controversy
Even as various texts insist that the level of susceptibility of a patient to a cancerous risk fundamentally hinges on the dosage applied by the medical practitioner; salient elements of the impact of the dose have not been critically factored in this assertion. This is informed by the fact that dosimetric parameters have different connotations at all times and while some can be out rightly measured, others cannot. For instance, factors like computed tomographic dose index and the dose length product can easily be measured. On the other hand, other factors informed by the nature of the patient; like Effective Dose Estimate (E) and the risk of a non-asymmetrical irradiation of a certain part of the body which is under treatment or diagnosis. The former set of features is only dependent with the physiological construction of a patient’s body and thus lead to variation in dosage from one patient to another. Owing to this, there is no precise estimation of impact of radioactivity on a patient per treatment.
Respective CT scanner settings
The ultimate quantity of radioactive emission from a CT scanner can be varied either way through regulation by the operator. The overarching obligation on every medical practitioner is to strike a balance between reducing the patient’s dose to a relatively low level as against ensuring that the clarity of the images showing is still sanctified significantly for ease of interpretation.
It is from the above premise that various ways have been devised in a bid to reduce radioactive emissions during Computed Tomographic Angiography. The first is the Electrocardiographically controlled tube current modulation (ECTCM). The most recent study of radiation dose from CTA indicated that this method reduced radioactive emissions by 25% having been used by 73% of the patients (Hausleiter J, Meyer T, Hermann F, et al 2009).
Another tool that has been efficiently utilized to reduce the radiation dose is prospective scanning. Prospective scanning effectively closes down activity of X-rays during the CTA process. A study comparing prospective and retrospective angiography was conducted in 2008 (Hirai N, Horiguchi J, Fujioka C, et al 2008). With respect to ECG gated 64-Detector CTA, the average acquisition time of data using prospective ECG gated 64-detector was way lower than that of the retrospective one; 1.1% against 1.5%. There was no disparity when it comes to the image quality of the chest cross sectional area as produced by these two CTA models. Also, it was found out that there was absolute concurrence between prospective CT Angiography and retrospective CT Angiography with respect to detection of coronary artery stenosis. Finally, the calculated effective dose was lower by 79% from the prospective CT Angiography point of view compared to the retrospective CT Angiography. This study implies that the most favorable CT Angiography scan tool is prospective CT Angiography because it can lower the radiation dose subjected to patients and at the same time not jeopardize the quality of the image produced. It is equally able to assess luminal obstructions which are predominantly exhibited with patients of low than 75 beats per minute. This study was an extension and confirmation of a previous survey examining variations in radiation dose and image quality between prospective CT Angiography and retrospective CT Angiography (Shuman W, Branch K, May J, et al. 2008).
Aside from the above illustrated methods, radiation dose can also be reduced through sequential scanning and reducing the tube voltages; which are the latest approaches in this subject (Bowman A, Kantor B, Gerber T; 2009).
Discussion
In light of the information given above and the arguments made in this paper, there are a number of keynotes that can be made to wrap up the whole debate. In the first place, it must be acknowledged within the clinical fraternity that there is need to examine further the pros and cons of Computed Tomographic Angiography so as to find the best way of diagnosing patients; and this is applicable on a case to case basis. In as much as CT Angiography for coronary arterial disease is one of the most effective diagnostic tools for the disease, it cannot be forgotten that a deontological approach of examining the model with the best possible outcome has to be taken (Bowman A, Kantor B, Gerber T; 2009).
It has emerged that there is no conventional radiation dose which is applicable for a specific case study because of various variant factors like age, sex and even the patient’s immunity strength and resistance to c...