Congress:
EuroSafe Imaging 2019
Keywords:
Dosimetry, Image manipulation / Reconstruction, CT, Radiation physics, Radioprotection / Radiation dose, Thorax, Action 6 - Clinical audit tool for imaging, Action 4 - Dose management systems, Action 3 - Image quality assessment based on clinical indications, Perception image, Radiation safety, Dosimetric comparison, Quality assurance
Authors:
A. Al-Rasbi, H. Al Dhuhli, S. Raniga, Y. Bouchareb, H. Al-Ghafri
DOI:
10.26044/esi2019/ESI-0113
Background/introduction
The continuing advances in techniques and capabilities of Computed Tomography (CT) technology have resulted in reliable and excellent image quality.
These technical developments in CT have led to important clinical applications resulting in increased utilization of the CT scans.
This increase has considerably contributed to the rise in radiation exposure of the patients [1-5].
Despite the enormous efforts made by the CT manufacturers to design and develop techniques,
aiming to improve scanning efficiency,
image quality,
and radiation dose reduction,
CT still accounts for high exposure doses associated with the medical imaging.
Due to the growing concerns about CT high radiation doses,
many studies have discussed the potential risks associated with CT examinations and strongly emphasized on the need to put in place appropriate strategies for the dose optimization [6-10].
These strategies are primarily ensuring proper clinical justification of clinical indications for CT,
followed by appropriate CT optimization methods. Many investigators have proposed and reported various techniques and methods in achieving dose reduction while preserving the image quality for different CT protocols.
Generally,
most of these methods are based on modifying the conventional techniques,
which are available on most CT scanners,
regardless of the models,
by adjusting the scanning parameters.
Particular attention has been paid to chest CT because it is related to direct exposure of radiosensitive tissues including lungs,
breasts,
and thyroid.
Chest CT is widely used to diagnose various abnormalities and diseases related to chest organs.
Since lungs have low x-ray absorption and high inherent contrast,
chest CT is usually acquired with low doses compared to abdomen CT.
Many studies have investigated optimizing chest CT protocols,
aiming to achieve further dose reduction,
have revealed substantial radiation dose reduction without compromising image quality [11-16].
In response to the emphasis on dose optimization,
Department of Radiology and Molecular imaging at SQUH has recently reviewed the most common CT protocols.
The local CT protocols,
which use automatic tube current modulation (ATCM),
were designed with predefined exposure settings based on the clinical indication and the anatomical region to be scanned.
The conclusion taken out of this review is that these protocols need to be: (i) further optimized by adjusting the exposure parameters to the patient’s size for each clinical indication and (ii) assessed utilizing the image quality and dose reduction on a large patient population.
A preliminary assessment was carried out to evaluate the dose reduction and to check if the radiologists have raised any remarks regarding the image quality.
It is worth mentioning that the previous clinical reports of the clinical cases,
which were scanned with the post-optimized settings did not highlight issues with the image quality.
However,
it was essential to perform a statistically reliable assessment that should address both the significance of the dose reduction and the evaluation of the image quality. This study explored the potential of reducing the radiation doses in chest CT without affecting image quality on patients who had been scanned twice during the year 2018.