[Institution Title]
Introduction
Quality control program for computed tomography (CT) scan is defined as a process or system that is designed to ensure that the performance of the scanner is still within the set standard (Seeram, 2015, p.432). This is accomplished using quality control tests. The result of a specific QC test for a given CT scanner is compared with other brands of CT scanners in the market. The purpose of quality control testing for CT scans is to ensure that every image produced by the machine is of good quality—clear, and readable, while still ensuring the lowest dose of radiation for patients and personnel (Seeram, 2015, p.432). The need for securing a high quality image from CT scanning machines is very important for radiologist especially for producing accurate diagnosis and interpretation based on the information projected in the CT images. This paper would like to describe the different essentials steps in conducting quality control for CT scans. Furthermore, this paper will review one of the eighteen (18) quality control tests used for computed tomographic scanners.
Essential Steps in Conducting Quality Control for CT Scans
According to Euclid Seeram (2015), there are three essential steps in a quality control program for testing CT scanners. These include the following: (a) acceptance testing, (b) routine performance evaluation, and (c) error correction (Seeram, 2015, p.432).
Acceptance testing only verifies the accuracy of the details in the unit whether it is according to the specifications identified by the manufacturer. Furthermore, it also details the ability of the unit to meet the specific requirements set by the hospital who made the purchase. The result of the testing must satisfy all the details specified in this section to ensure efficiency of the unit particularly relating to quality image and dose requirement. This process is usually done by a physicist or a technician who has full knowledge and is qualified to make a conclusion because they have the full knowledge of how scanners operate.
Routine Performance Evaluation
A routine performance evaluation is conducted on a regular basis for the purpose of monitoring. This process assesses whether the components of the CT scan impacts the quality of the image and the dose. This is typically performed on a schedule—either on a daily, weekly, monthly or yearly basis. Depending on who ordered the routine performance evaluation, the procedure should be done or conducted by either a medical physicist or a technologist. The order usually comes from medical authorities like the International Atomic Energy Agency, Health Canada, and American College of Radiology.
Error Correction
When quality control tests are completed, error correction are conducted. Error correction deals with the evaluation of the quality control results to address any discrepancies or lapses relating to the tolerance and acceptance limit that is set for a specific quality control test. The scanner that failed the test should be serviced to ensure that it meets the standard or tolerance limit set for the unit.
The West Physics Low Contrast Resolution
There are different quality control tests for CT scanners. Every test is designed to address a specific function of the computed tomographic (CT) scanner. One of the quality control test for CT scanners is the West Physics Low Contrast Resolution is designed to address the efficiency, effectiveness, and quality of the function of the CT scan in terms of the resolution in the application of fluoroscopy and radiography . The West Physics Low Contrast Resolution Test is defined as convenient and compact. It is intended to measure the low contrast resolution of the CT scanner. However, in a study conducted in 1984 specifies that the use of low contrast resolution test have limitations as far as contrast-detailed diagrams . The said study reports that the low contrast resolution test interprets the physical performance parameters of the CT scan particularly relating to dose, noise, slice width, and spatial resolution (Goodenough & Weaver, 1984, pp. 304-305).
Typically, the west physics low contrast resolution test is conducted monthly by a service personnel and technologists. This particular test is designed to assess the quality of images produced by computed tomography scanners. The object being measured is connected to attenuation, which is represented using the objects Hounsfield value.
There are different factors and parameters that affects the test result relating to low contrast resolution. These parameters include (1) the observer (personal biases, experience, goals), (2) scan parameters (dose distribution, dose, collimation), (3) reconstruction parameters (in-plane resolution, slice thickness, reconstruction kernel), (4) reading conditions (monitor, ambient light, ability to window), (5) evaluation, (6) phantom (the manufactured quality, pattern of inserts, reproducibility), (7) scanner (dose efficiency, detector, scatter radiation, artifact suppression), and (8) low contrast object (size, density, background material, shape) .
Conclusion
Quality control is paramount to ensure the effectiveness and efficiency of a particular product. This is most specifically true for CT scanners considering the importance of the unit in diagnosing diseases and medical condition.
Reference
Goodenough, D., & Weaver, K. (1984). Factors related to low contrast resolution in CT scanners. Computerized Radiology, 297-308.
Medical Physicist. (2016, January 23). Low Contrast Resolution Phantom. Retrieved from Medical Physicist Website: http://www.westphysics.com/products/low-contrast-resolution-phantom/
Seeram, E. (2015). Computed Tomography: Physical Principles, Clinical Applications, and Quality Control. Philadelphia, Pennsylvania: Elsevier Health Sciences.
Ulzheimer, S. (2013, June 7). Image Quality in Computed Tomography. Retrieved from Siemens Global Website: http://health.siemens.com/ct_applications/somatomsessions/index.php/image-quality-in-computed-tomography/
