Low-dose X-ray therapy for COVID-19: lessons from the past

Coronavirus disease 19 (Covid-19) poses a huge threat to health systems and economies worldwide. So far, there has been no proven effective treatment for SARS-CoV-2 infection. Various potential therapies, viz., immunomodulatory agents, antiviral therapy, and plasma transfusion, are undergoing clinical trials. An intensive search of the medical corpora revealed that low dose X-ray radiation therapy has been used in the past to treat interstitial pneumonia. In this article we explore a historical background of low-dose X-rays for the treatment of pneumonia and how it could be a promising therapy in treating patients with COVID-19.     

Head CT: Image quality improvement with ASIR-V using a reduced radiation dose protocol for children

Objective

To investigate the quality of images reconstructed with adaptive statistical iterative reconstruction V (ASIR-V), using pediatric head CT protocols.

Methods

A phantom was scanned at decreasing 20% mA intervals using our standard pediatric head CT protocols. Each study was then reconstructed at 10% ASIR-V intervals. After the phantom study, we reduced mA by 10% in the protocol for <3-year-old patients and applied 30% ASIR-V and by 30% in the protocol for 3- to 15-year-old patients and applied 40% ASIR-V.

Results

Increasing the percentage of ASIR-V resulted in lower noise and higher contrast-to-noise ratio (CNR) and preserved spatial resolution in the phantom study. Compared to a conventional-protocol, reduced-dose protocol with ASIR-V achieved 12.8% to 34.0% of dose reduction and showed images of lower noise (9.22 vs. 10.73, P?=?0.043) and higher CNR in different levels (centrum semiovale, 2.14 vs. 1.52, P?=?0.003; basal ganglia, 1.46 vs. 1.07, P?=?0.001; and cerebellum, 2.18 vs. 1.33, P?<?0.001). Qualitative analysis showed higher gray-white matter differentiation and sharpness and preserved overall diagnostic quality in the images with ASIR-V.

Conclusions

Use of ASIR-V allowed a 12.8% to 34.0% dose reduction in each age group with potential to improve image quality.

Key points

? It is possible to reduce radiation dose and improve image quality with ASIR-V. ? We improved noise and CNR and decreased radiation dose. ? Sharpness improved with ASIR-V. ? Total radiation dose was decreased by 12.8% to 34.0%.

     

Quantitative assessment of quality of digitized portal images: receiver operating characteristic analysis applied to imaging in radiation therapy

An objective and quantitative method for the evaluation of the quality of megavoltage portal images was developed by applying receiver operating characteristic analysis. On the basis of therapeutic use of portal images, setup errors were employed as "signals" in this experimental study that compared the original portal films with digitized images. Six readers observed 104 portal images of a chest phantom, half of which were "abnormal" (ie, had setup errors). Digital images (2,048 x 2,048 matrix) were enhanced by means of histogram equalization and then printed with a laser printer for observation. The readers showed a higher discrimination capacity with the digitally enhanced images, although a statistically significant improvement was not demonstrated. The present method of assessment of image quality proved to be both simple and clinically reasonable.     

Breast imaging: from 1965 to the present

The current state of the art for breast imaging is reviewed in comparison with the methods of practice commonly in use 25-35 years ago to demonstrate the most important advances that have taken place in imaging techniques, operational considerations, interpretive approaches, and interventional procedures. Since 1965, breast imaging has progressed from the simple assessment of breast disease in a selected small number of symptomatic women to the comprehensive evaluation of both breast health and disease in a substantial percentage of all women aged 40 years and older. In the process, breast imaging has become an established radiologic subspecialty that accounts for at least 10% of all examinations performed by radiologists. Indeed, mammography now is the most common imaging examination that directly results in the reduction of mortality from disease.     

Low-dose CT of the paranasal sinuses with eye lens protection: effect on image quality and radiation dose

The purpose of the study was to assess the effect of lens protection on image quality and radiation dose to the eye lenses in CT of the paranasal sinuses. In 127 patients referred to rule out sinusitis, an axial spiral CT with a lens protection placed on the patients eyes was obtained (1.5/2/1, 50 mAs, 120 kV). Coronal views were reconstructed at 5-mm interval. To quantify a subjective impression of image quality, three regions of interest within the eyeball were plotted along a line perpendicular to the protection at 2, 5, and 9 mm beneath skin level on the axial images. Additionally, dose reduction of a bismuth-containing latex shield was measured using a film-dosimetry technique. The average eyeball density was 17.97 HU (SD 3.7 HU). The relative increase in CT density was 180.6 (17.7), 103.3 (11.7), and 53.6 HU (9.2), respectively. There was no diagnostic information loss on axial and coronal views observed. Artifacts were practically invisible on images viewed in a bone window/level setting. The use of the shield reduced skin radiation from 7.5 to 4.5 mGy. The utilization of a radioprotection to the eye lenses in paranasal CT is a suitable and effective means of reducing skin radiation by 40%.     

Using quality improvement to manage the installation of capital equipment

The traditional process for capital equipment installation in healthcare settings is often not managed to maximum effectiveness. Cost overruns from unplanned construction or from construction change orders are frequently caused by breakdowns in communications between architects, equipment vendors, building contractors, and managers of healthcare services. Through the use of a continuous quality improvement philosophy, it is possible to redefine the installation process and thereby enable the healthcare facility to streamline the costs of capital acquisition.