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Introduction Methods Results Conclusion Size‐specific dose estimates (SSDE) are used to assess patient‐specific radiation exposure in Computed Tomography (CT), complementing the volume CT dose index (CTDIvol). This study compared SSDE calculated using patient's lateral size from scan projection radiograph (SPR) with SSDE calculated using water equivalent diameter (Dw) from tomographic images in adult chest high‐resolution CT (HRCT).In a single‐centre study, the CTDIvol and dose‐length product (DLP) were recorded from HRCT dose reports of adult patients. Lateral width (SLat), at the centre of the scan range, from the SPR was measured and the SSDE (SSDER) was calculated using conversion factors related to SLat. Average CT number, area of the slice, and lateral size of the patient (AxLat) were measured on the middle slice. The Dw and SSDE from Dw (SSDEW) were calculated. SSDER and SSDEW were compared using Wilcoxon signed rank test. Correlation between patient size and dosimetry parameters were investigated using Spearman Correlation test with statistical significance at P < 0.05. Bland–Altman plot was also used to test agreement between the two SSDE values.Median CTDIvol, DLP, SSDER and SSDEW were 11.0 mGy, 372 mGy.cm, 11.6 mGy and 12.9 mGy, respectively. Small but statistically significant differences (P < 0.03) were found between SLat and AxLat as well as between SSDER and SSDEW. Bland–Altman analysis resulted in borderline agreement between SSDE values. Moderate correlations were observed between dosimetry quantities and patient size measurements (ρ > 0.640; P < 0.001). SSDEw showed statistically significant correlation (ρ = 0.587 and P < 0.001) with SSDER.SSDER may be used to assess patients' absorbed radiation dose, before the scan, in adult chest HRCT. The median value of SSDER was about 10% lower than the median value SSDEW. However, the SSDEW should be used after the scan to establish effective dose and radiation risk to the patient. [ABSTRACT FROM AUTHOR]

Artificial intelligence has been used effectively in medical diagnosis. The objective of this project is to examine the application of a collective AI model using weighted fusion of predicted probabilities from different AI architectures to diagnose various retinal conditions based on optical coherence tomography (OCT). A publicly available Noor dataset, comprising 16,822, images from 554 retinal OCT scans of 441 patients, was used to predict a diverse spectrum of age-related macular degeneration (AMD) stages: normal, drusen, or choroidal neovascularization. These predictions were compared with predictions from ResNet, EfficientNet, and Attention models, respectively, using precision, recall, F1 score, and confusion matric and receiver operating characteristics curves. Our collective model demonstrated superior accuracy in classifying AMD compared to individual ResNet, EfficientNet, and Attention models, showcasing the effectiveness of using trainable weights in the ensemble fusion process, where these weights dynamically adapt during training rather than being fixed values. Specifically, our ensemble model achieved an accuracy of 91.88%, precision of 92.54%, recall of 92.01%, and F1 score of 92.03%, outperforming individual models. Our model also highlights the refinement process undertaken through a thorough examination of initially misclassified cases, leading to significant improvements in the model's accuracy rate to 97%. This study also underscores the potential of AI as a valuable tool in ophthalmology. The proposed ensemble model, combining different mechanisms highlights the benefits of model fusion for complex medical image analysis. [ABSTRACT FROM AUTHOR]

Context Dry-processed radiographic films should be stored in a temperature-controlled environment away from direct light to prevent image deterioration. However, films occasionally are subjected to other conditions, such as when they are left inadvertently on viewing boxes or removed from the radiology department. Objective To assess the effects of heat and light on optical density in radiographic films produced with dry laser imagers. Methods Step-wedge images generated by a dry laser imaging system were placed on an illuminated viewing box, inside the trunk of a car and in direct sunlight on a hot day for varying lengths of time. Changes in optical density (OD) then were measured with a densitometer. Changes of more than 2 standard deviations from the original OD were attributed to the effects of light and heat. Results The films left on a viewing box and inside a car's trunk did not show significant changes in OD. However, films subjected to direct sunlight for 30 minutes or more at an average temperature of 40°C (104°F) showed significant changes in OD in the straightline portion of the Hurter and Driffield curve. Conclusion Dry-processed films can degrade when exposed to temperatures higher than 35°C (95°F) and should be stored properly to avoid affecting their diagnostic quality., The use of dry laser imagers has become widespread in radiology departments in Kuwait in the past 5 years. Most digital imaging modalities, including computed tomography, magnetic resonance imaging, ultrasound, [...]

Objective To compare the radiation dose during pelvic x-ray examinations using computed radiography (CR) and film-screen (FS) radiography at various x-ray tube voltages (kV) and tube-current time product (mAs) values. Methods A pelvic phantom was imaged using FS and CR systems. The entrance surface dose was measured using an ionization chamber, and the gonadal dose and effective dose were calculated using the XDOSE program. The diagnostic quality of the images was assessed using a 5-point subjective scoring system. Results At standard kV values, the image quality did not vary significantly between the CR and the FS system, but at higher kV values, the CR images were found to be of better quality than FS images. In addition, the lower limit of entrance skin dose consistent with diagnostically acceptable CR images was 50% lower than that for FS images. Conclusion The gonadal dose and effective dose for pelvic x-ray examinations can be reduced by 50% when CR systems are used and appropriate exposure factors are established., Computed radiography (CR) systems have replaced the conventional film-screen (FS) systems in radiology departments worldwide. In conventional FS radiography, light from intensifying screens, which convert x-rays into visible light, forms [...]

This study investigated the comparative stabilities of wet and dry laser imaging systems using 4 different imagers: 2 wet and 2 dry systems. Fifteen step wedge films, generated by built-in software from each imager, were collected over a period of 25 days. The stability of each system was assessed by computing the average and standard deviation of the percentage coefficients of variation for the optical densities of the steps. Small, but statistically significant, differences between the mean coefficient of variation values were found, with no significant trend toward either system. Wet imaging systems recorded lower speed index values than dry systems, but there was no definite trend toward either type for contrast index. Both imaging systems are equally stable in their performance; however; regular quality control checks are essential to monitor abnormal behavior., Recording a hard copy of a digital image is done by exposing a film with emulsion coating to light (mainly laser light) and then developing the film by wet chemical [...]

Radiation dose to patients from imaging modalities is measured or calculated to assess the risk of the procedure and compare it with the benefits. Periodic review of image acquisition methods and the radiation dose used are an essential part of optimization in medical imaging. The aim of this study was to estimate patient radiation dose from SPECT myocardial perfusion imaging (MPI) using CT images for attenuation correction. Methods: SPECT and CT image acquisition parameters such as administered activity (AA), CT dose index (CTDIvol), and dose-length product for 415 patients who had undergone SPECT MPI using CT attenuation correction were reviewed. Effective dose (ED) for the SPECT part, the CT part and the total ED for the procedure were calculated. AA, CTDIvol, and ED values were compared between the 2 sexes and between body mass indexes (BMIs), imaging scanner models, and imaging centers. Statistical analyses were performed using t tests and 1-way ANOVA at P < 0.05 level of significance. Results: The range of AAs used for MPI was found to be 1,206-1,964 MBq per patient regardless of sex. The resulting mean ED of 8.8 mSv for men was significantly lower (P = 0.002) than the 10.4 mSv for women for SPECT. The range of CTDIvol was 1.12-3.97 mGy, resulting in an mean ED of 0.8 mSv for men, significantly lower (P < 0.001) than the 1.1 mSv for women for CT. The average combined EDs for male and female patients were 9.6 and 11.5 mSv, respectively. A positive correlation was found between AA and patient BMI (r = 0.48; P < 0.001), indicating patient size-related AAs. However, CTDIvol was found to depend only on the scanner model, regardless of BMI. Conclusion: The ED from SPECT/CT MPI studies was around 11 mSv, with 10 mSv being from the SPECT part of the study. The extra risk to the patients from CT imaging for attenuation correction is small compared with the benefit incurred from accurate diagnosis. [ABSTRACT FROM AUTHOR]

Purpose To establish the extent of dose reduction that can be achieved using a computed tomography (CT) quality assurance phantom with various user-defined protocols at different milliamperage (mA) settings and kilovoltage peak (kVp) without affecting image quality. Methods Images of a CT quality assurance phantom containing line-pair patterns and 3 tissue-equivalent inserts in water were acquired with different mA settings on 4 different CT scanners. The kVp was kept constant at 120 while the mA was changed in increments of 20, from 30 mA to 190 mA. Three images from each series acquired at different mA settings were selected: one each for the quantitative analysis of spatial resolution, contrast-to-noise ratio (CNR), and image noise using image analysis freeware. Results Statistical analysis was carried out with a statistical probability of P < .05 indicating significant difference. Results of the statistical analysis revealed significant differences in the CNR of all 3 types of tissue-equivalent inserts (P < .001) and in image noise (P < .001) as the mA was changed. However, changes in mA did not produce significant differences in the spatial resolution of the images (P > .06). Conclusion A radiation dose reduction of 25% was achieved in 4 different CT scanners without significantly affecting the 3 image quality parameters. [ABSTRACT FROM AUTHOR]

Objective: The effect of time delay between last erasure and image acquisition using computed radiography (CR) image plates (IPs) was investigated using an Agfa ADC Compact CR system. Method: IPs of various sizes were erased by the IP processing cycle of the CR system. These IPs then were stored in their normal storage place for various durations, ranging from 0 hours to 168 hours. The IPs then were processed, and dark noise images were obtained. The dark noise in each plate was estimated by measuring the average pixel value in several places on the image. Statistical analysis was carried out using 1-way analysis of variance and Kruskal-Wallis testing for any significant differences in dark noise between time delays at P = .05. Regression analysis was carried out to test any relationship between dark noise and time delay. Results: Statistically significant (P < .05) increases in dark current were observed when the time delay increased, with increase greater than 40% for time delays more than 24 hours. In the short term (< 1 hour), a quadratic relationship was observed, and in the long term (> 24 hours) a linear relationship was observed between dark current and time delay. Conclusion: Dark noise increases with time delay, and it is useful to erase the IP before image acquisition if time delays of more than 24 hours are experienced, such as over a weekend. [ABSTRACT FROM AUTHOR]