Tradeoffs between Radiation Exposure to the Lens of the Eyes and Diagnostic Image Quality in Pediatric Brain Computed Tomography.

Background: Computed tomography (CT) of the brain is associated with radiation exposure to the lens of the eyes. Therefore, it is necessary to optimize scan settings to keep radiation exposure as low as reasonably achievable without compromising diagnostic image information. The aim of this study was to compare the effectiveness of the five practical techniques for lowering eye radiation exposure and their effects on diagnostic image quality in pediatric brain CT. Methods: The following scan protocols were performed: reference scan, 0.06-mm Pbeq bismuth shield, 30% globally lowering tube current (GLTC), reducing tube voltage (RTV) from 120 to 90 kVp, gantry tilting, and combination of gantry tilting with bismuth shielding. Radiation measurements were performed using thermoluminescence dosimeters. Objective and subjective image quality was evaluated. Results: All strategies significantly reduced eye dose, and increased the posterior fossa artifact index and the temporal lobe artifact index, relative to the reference scan. GLTC and RTV increased image noise, leading to a decrease signal-to-noise ratio and contrast-to-noise ratio. Except for bismuth shielding, subjective image quality was relatively the same as the reference scan. Conclusions: Gantry tilting may be the most effective method for reducing eye radiation exposure in pediatric brain CT. When the scanner does not support gantry tilting, GLTC might be an alternative.

Radiation Exposure and Lifetime Attributable Risk of Cancer Incidence and Mortality from Low- and Standard-Dose CT Chest: Implications for COVID-19 Pneumonia Subjects.

Since the novel coronavirus disease 2019 (COVID-19) outbreak, there has been an unprecedented increase in the acquisition of chest computed tomography (CT) scans. Nearly 616 million people have been infected by COVID-19 worldwide to date, of whom many were subjected to CT scanning. CT exposes the patients to hazardous ionizing radiation, which can damage the genetic material in the cells, leading to stochastic health effects in the form of heritable genetic mutations and increased cancer risk. These probabilistic, long-term carcinogenic effects of radiation can be seen over a lifetime and may sometimes take several decades to manifest. This review briefly describes what is known about the health effects of radiation, the lowest dose for which there exists compelling evidence about increased radiation-induced cancer risk and the evidence regarding this risk at typical CT doses. The lifetime attributable risk (LAR) of cancer from low- and standard-dose chest CT scans performed in COVID-19 subjects is also discussed along with the projected number of future cancers that could be related to chest CT scans performed during the COVID-19 pandemic. The LAR of cancer Incidence from chest CT has also been compared with those from other radiation sources, daily life risks and lifetime baseline risk.

A Study on Radiation Dose Received by Patients during Extracorporeal Shock Wave Lithotripsy.

BACKGROUND: Extracorporeal shock wave lithotripsy (ESWL) is considered as the method of choice for treatment of most stone diseases. The present study aims to evaluate radiation dose received by patients undergoing ESWL. METHODS: In total, 46 patients from both genders were referred to the Shohadaye Ashayer hospital of Khorramabad, Iran and were included in the present study. Patients were positioned in anteroposterior (AP) projection and along 30° anterior oblique (AO) projection upon the X-ray fluoroscopy table and exposures were conducted. Thermoluminescent dosimeters (TLDs) were used for radiation dose measurements. To evaluate the entrance surface dose (ESD), each TLD chip was taped on back of patient at the entrance surfaces of the X-ray beam. RESULTS: The mean number of stones in each patient was 1.4. The stone sizes ranged from 7 to 29 mm, and a mean of 3200 pulses were need for each patient. The mean ESD in the postero-anterior (PA) and oblique X-ray beam entrance were obtained at 12.04 and 68.84 mGy, respectively. There was linear correlation between patient dose with fluoroscopy time, tube current (mA), tube potential (kVp) and patient position (P < 0.001); however, we found no strong correlation between patient dose with patient body mass (P = 0.837), number of shock wave pulses (P = 0.089), stone size (P = 0.773) and locations (P = 0.463). CONCLUSION: The data obtained in the current study are comparable with information available in the literature. They emphasized that ESWL exposes patients to much more radiation compared to those from conventional radiography and is in the range of computed tomography (CT) procedures. Therefore, following safety guidelines is recommended.

Gonad Shielding during Pelvic Radiography: A Systematic Review and Meta-analysis.

BACKGROUND: Gonad shielding has been extensively advocated during pelvic radiography at or below reproductive ages. The popular practice of gonad shielding is placement of a lead shield in the midline of the pelvis. The aim of this study was to address the prevalence of gonad shielding and find out whether the current practice of gonad shielding can be considered as an effective method to reduce radiation exposure in patients undergoing pelvic radiography. METHODS: National and international electronic databases, including PubMed, MEDLIN, EMBASE, and Google-Scholar, were searched up to January 2016. The database searches were supplemented with manual searches of reference lists. Two authors independently assessed the eligibility of all studies and extracted data. RESULTS: The searches yielded a total of 243 publications. After assessing each identified study against specific inclusion exclusion criteria, 18 studies were deemed as relevant for this review. The total prevalence rate of gonad shielding was estimated at 58% (95% CI: 40 to 74%). It was estimated that only 34% (95% CI: 25 to 44%) of the radiographs had correct positioning of the shield. Also, incorrect positioning of the shield was statistically significantly higher in females than males (85% vs. 52 %; P-value < 0.001). CONCLUSIONS: Our study demonstrates that the current practice of gonad shielding during female pelvic radiography should be no longer considered as an effective method to reduce radiation exposure. Training the best qualified radiographers is the key to accurate positioning of the shield in male subjects.