Photon-counting detector CT (PCD-CT) represents a transformative advancement in CT technology, overcoming limitations of conventional energy-integrating detector (EID) based systems. It uses semiconductor materials such as cadmium telluride, cadmium zinc telluride, and silicon to directly count X-ray photons while resolving their energy levels. This energy-resolving capability ensures equal weighting of low- and high-energy photons, eliminates electronic noise, and enables material-specific imaging. The absence of physical septa in the detector-used in EIDs to prevent light photon cross-talk-results in smaller effective detector pixels in PCD-CT, enhancing detection efficiency and spatial resolution. These innovations collectively enhance diagnostic accuracy while enabling significant radiation dose reduction. This article provides a comprehensive overview of PCD-CT technology, comparing it with EID-based systems. It highlights key advantages such as superior spatial and contrast resolution, spectral imaging, and noise reduction. Additionally, the review discusses PCD-CT's radiation dose reduction across cardiovascular, thoracic, abdominal, musculoskeletal, neuroimaging, and paediatric applications. Despite its promise, PCD-CT faces challenges, including non-ideal detector performance, increased electronic complexity, and calibration requirements to maintain accuracy. Addressing these issues will be crucial for widespread clinical adoption. As research progresses and technology improves, PCD-CT is expected to reshape clinical practice by integrating high diagnostic accuracy with improved radiation efficiency.

OBJECTIVE:The volume of fluoroscopically guided interventions (FGIs) performed by vascular surgeons has increased significantly nationwide; however, appropriate and timely radiation safety training varies by institution. Vascular surgery trainees often learn radiation safety techniques concurrently with learning the art of vascular surgery. Given the concern for occupational hazards throughout clinical training, we sought to determine the radiation dose exposure to trainees, faculty surgeons, and patients during FGIs according to the level of training. METHODS:A prospective cohort study was performed at a university hospital to determine the median body radiation dose of trainees, attending surgeon, and patients during FGIs over a 5-month period. Optically stimulated luminescence dosimeters were placed outside the lead apron at the thyroid and sternum positions for one attending surgeon and all assisting fellows performing FGIs. Cases were stratified according to fellow training stage: first 6 months in the first year (postgraduate year [PGY]6) and final 6 months of the second year (PGY7). Operator radiation dose was calculated based on a calibration of 80 kVp. Procedural reference air kerma (RAK), fluoroscopy time, dose area product (DAP), and patient body mass index were recorded. Scatter fractions were measured with the thyroid and sternum counts to DAP ratio and the DAP/RAK ratio (a surrogate for collimation and use of magnification). Paired Wilcoxon and χ2 tests were performed to identify statistical significance of training stage on radiation dose exposure and performance of radiation reduction. RESULTS:A total of 40 FGIs were performed: 21 cases with PGY6 fellows and 19 cases with PGY7 fellows. Higher median thyroid and sternum radiation doses were observed for PGY6 fellows than for PGY7 fellows, respectively (82 μGy [interquartile range (IQR): 47-94 μGy] vs 44 μGy [IQR: 30-57 μGy], P = .009; 89 μGy [IQR: 75-128 μGy] vs 54 μGy [IQR: 48-77 μGy], P = .007). Scatter fractions, as measured by the thyroid/DAP and sternum/DAP ratios, were significantly higher for first-year fellows (2 vs 1, P = .018; 2.64 vs 1.23, P = .041). There was no difference in the source-to-image distance or the average field size as measured by the DAP/RAK ratio. CONCLUSIONS:Trainee radiation dose exposure is higher during the first year of fellowship. Acquisition of optimal performance with fluoroscopy skills can be related to training time. The difference noted between PGY6 and PGY7s is likely enhanced for vascular residents (PGY1-5) and further underscores the importance of early and thorough education in radiation safety for all trainees.

Objective: Protective garments are part of the routine radiation safety equipment used during fluoroscopically guided interventions (FGIs). New elements and lead equivalences have been introduced by manufacturers, which may influence protection for interventionalists from ionizing radiation. We sought to determine the performance of different lead-equivalent apron vests during FGIs in clinical and simulated scenarios. Methods: Our primary endpoint was to evaluate the effectiveness of radiation dose attenuation of two different protective leaded apron vests, one with nominal 0.5-mm lead equivalence and a second with 0.35-mm lead equivalence, which were evaluated in clinical and simulated settings. In the clinical setting, optically stimulated luminescence nanoDotTM detectors were placed at the upper outer quadrant (UOQ) chest wall (CW) position, both over and under the apron vests on one vascular surgeon performing FGIs over a 21-month period. All interventions were performed in hybrid rooms with Allura Clarity (Phillips Healthcare) C-arms with state of-the-art software for vessel navigation, digital subtraction angiography, digital magnification, and collimation. Dosimeters were placed on either side of the primary operator's body, located on the side closest to the X-ray source. In the simulation, fluorography was performed on a 30-inch-thick acrylic scatter phantom at 68, 80, 100, and 120 kVp for an exposure of 2000 mGy reference air kerma. Experiments were performed on the 0.35-mm and 0.5-mm lead-equivalent aprons. Paired Wilcoxon, X-2, and analysis of variance tests were performed to identify statistical significance of radiation attenuation dose rates. Results: Operator UOQ CW radiation dose was measured during 32 FGIs: 16 were performed with the 0.5-mm lead-equivalent apron and 16 with the 0.35-mm lead-equivalent apron. Median procedure reference air kerma was 167 mGy (interquartile range, 99-437 mGy) when the 0.5-mm apron vest was worn vs 250 mGy (interquartile range, 144-410 mGy) with the 0.35-mm vest. There was no significant difference in UOQ CW radiation dose attenuation between the two lead equivalencies: thick 89% vs thin 86%; P = .2. In the simulated scenario, radiation dose attenuation was similar for all measured kVp, with no significant differences for both apron vests (94% thick vs 95% thin; P = .49). Conclusions: Heavier leaded aprons do not offer clinically significant increased protection over thinner lead. Due to the long-term musculoskeletal strain on interventionalists, it is safe to consider lightweight lead protection. (JVS-Vascular Insights 2025;3:100154.)

OBJECTIVE:Although it is contraindicated for physicians performing fluoroscopically guided interventions (FGIs) to position their hand directly in the beam, it can be unavoidable and results in greater operator exposure and risk. Clinical guidelines recommend against the use of radiation-protective gloves (PGs) during FGIs given the concern for higher radiation accumulation related to increased procedure scatter fraction (PSF). We describe hand radiation dose and procedural scatter during FGIs with regular surgical gloves (RGs) compared to lead-free PGs. METHODS:Our primary end point was to evaluate hand radiation dose attenuation of tungsten PG and their effect on operator PSF. In the clinical setting, optically stimulated luminescence detectors were placed bilaterally at the volar and dorsal aspects of the operator's hands at the radioulnar joint and base of the ring finger. Control dots were positioned on the sternum. All operators were trained in applying as low as reasonably achievable principles. In the simulation, fluorography was performed on a 25 × 50 cm, 15-cm thick acrylic phantom for an exposure of 250 mGy reference air kerma. An anthropomorphic hand was placed at 7.5-cm intervals along the length of the table from the point of the fingertips at the center of the x-ray beam, 0 to 30 cm caudally. Radiation dose was calculated based on a calibration coefficient factor to estimate radiation at 80 kVp. The PSF was estimated by normalizing the sternum dose measurement with the dose area product. Wrist and finger radiation doses were normalized by dividing by the sternum dose to control for case length and procedure factors. A paired Wilcoxon test was performed to identify statistically significant differences of normalized PSF, finger, and wrist dose with RG vs PG. RESULTS:A total of 50 FGIs were performed: 25 with RGs and 25 with PGs. The median procedure reference air kerma was 98 mGy (interquartile range [IQR], 26-137 mGy) with RGs and 63 mGy (IQR, 38-134 mGy) with PGs. The hand radiation dose was lower for both dominant and nondominant hands with the PGs (270 μGy [IQR, 200-520 μGy] vs 590 μGy [IQR, 300-830 μGy], P = .015; and 260 μGy [IQR, 180-240 μGy] vs 660 μGy [IQR, 410-870 μGy]; P < .001) vs RGs. There was no significant increase in PSF with PGs vs RGs (4.46 [IQR, 3.15-5.67] vs 8.21 [IQR, 7.09-12.19]; P = .777). In the simulated setting, hand radiation dose was 58% lower with PG vs RG at all distances (8600 μGy vs 21,000 μGy; P < .001), with no significant differences in PSF for PGs vs RGs. CONCLUSIONS:Operator hands are directly in the x-ray beam more than recognized, leading to an increased lifetime risk. PGs can be expensive and cumbersome, but are effective at decreasing hand radiation exposure without increasing operator radiation dose. They should be considered for use in procedures where hand proximity to the beam is likely.

OBJECTIVE:Breast cancer most commonly occurs in the upper outer quadrant (UOQ) chest wall (CW). The effectiveness of routine leaded aprons to protect this region of the body in interventionalists during fluoroscopically guided interventions (FGIs) is unknown. Given the high lifetime attributable risks of prolonged occupational exposure to ionizing radiation and the increasing number of practicing female vascular surgeons and interventionalists, we sought to determine if the use of a leaded arm shield would offer additional protection to the lateral CW and axilla in operators compared with routine leaded aprons. METHODS:Effectiveness of leaded sleeves in attenuating radiation dose to the axilla and UOQ was evaluated in clinical practice and simulated scenarios. In the clinical setting, optically stimulated luminescence nanoDot detectors were placed at the UOQ lateral CW position, both over and under a standard leaded apron vest with and without the addition of an antimony/bismuth Enviro-Lite sleeve on two vascular surgeons performing FGIs. In the simulation, nanoDots were similarly placed on an anthropomorphic phantom positioned to represent a primary operator performing right femoral access. Fluorography was performed on 12-inch-thick acrylic scatter phantom at 80 kVp for an exposure of 3 Gy reference air kerma. Experiments were done with and without the sleeve. Paired Wilcoxon and χ2 tests were performed to identify the statistical significance of radiation attenuation. RESULTS:Operator UOQ CW dose was measured during 61 FGIs: 33 cases (54%) with and 28 cases (46%) without the sleeve. Median procedure reference air kerma and fluoroscopy time was 180 mGy (interquartile range [IQR], 85-447 mGy) and 21 minutes (IQR, 11-39 minutes) when the sleeve was worn vs 100 mGy (IQR, 67-270 mGy) and 11 minutes (IQR, 6.3-25 minutes) without the sleeve. Radiation dose to the operator's UOQ was reduced by 96% (IQR, 85%-96%) when the sleeve was present and by 62% (IQR, 44%-82%; P < .001) without the sleeve. In the simulated setting, the sleeve reduced the radiation dose to the UOQ compared with the apron alone (96% vs 67%; P < .001). CONCLUSIONS:Routine leaded aprons do attenuate the majority of UOQ chest wall radiation dose; however, the addition of a lead-equivalent sleeve further significantly reduces this dose. Because this area of the body has a high incidence of cancer formation, additional protection, especially to female interventionalists, seems prudent. Vascular surgeons should consider using a protective sleeve with their personal protective equipment when performing complex fluoroscopically guided procedures.

Background: The intensity of radiation scatter that emanates from the X-ray beam during fluoroscopically guided interventions is greater below the fluoroscopy table than above. Yet interventionalists' lower legs are typically unshielded and table skirts are often positioned incorrectly. We sought to characterize the efficacy of the leg protector wraps (Leg Wraps, Burlington Medical Inc.) in reducing the radiation dose to the operator's lower leg during fenestrated and branched endovascular aneurysm repair (F-BEVAR). Methods: A prospective cohort study was performed evaluating the lower leg radiation dose reduction of one vascular surgeon during F/BEVAR using antimony/bismuth Enviro-Lite leg wraps (0.35 mm lead equivalency, 99.7% attenuation at 50 kVp; Burlington Medical, Hampton Roads, Virginia). Optically Stimulated Luminescence nanoDot detectors (microSTARii System, LANDAUER, Inc., Glenwood, Illinois) were placed over and under the left leg wrap at the anterior tibial tuberosity position to compare operator leg dose with and without this additional protection. The table-mounted lead skirt was used consistently in all cases. The nanoDot detectors were cross-calibrated with a survey meter (RaySafe X2 survey sensor, Fluke Biomedical, Cleveland, Ohio) by measuring scattered radiation at a position equivalent to an operator's mid-tibia while performing digital acquisitions of a 25-cm thick, 30 cm x 30 cm acrylic phantom with a Philips FD20 fluoroscope (Philips Healthcare, Best, The Netherlands) with the table skirt removed. The measured radiation doses were converted to a Hp (0.07) skin dose, assuming an RQR6 beam spectrum (IEC-61267). Paired Wilcoxon test was performed to identify significant attenuation of radiation exposure. Results: Leg dose measurements from 40 F-BEVARs were analyzed. The patients had a median (interquartile range) body mass index of 27 (24-32) kg/m(2). Median procedure reference air kerma was 1,100 (728-1,601) mGy, kerma-area product was 127 (73-184) Gycm(2), and fluoroscopy time was 69 (54-86) min. The median skin dose H-p (0.07) over the leg wraps (n = 40) was 54.2 (24-100) mSv and under the leg wraps (n = 40) was 2.7 (mu)Sv (1.0-5.8). The leg wraps attenuated the radiation dose by 95% (89-98%) (P < 0.001). The unprotected, H-p (0.07) per kerma-area product was determined to be 0.38 ( 0.30e 0.55) (mu)Sv/Gycm(2). Conclusions: The 0.35-mm lead-equivalent leg wraps significantly decreased scattered radiation to the lower leg during F-BEVAR. Protective leg wraps should be recommended to operators performing complex fluoroscopically guided procedures.

Background: Radiation exposure and imaging quality are among the main concerns in endovascular procedures. The Clear VD11 PURE platform technology system (Siemens Healthineers, Erlangen, Germany) has been reported to lower the radiation dose and improve image quality. In the present study, we evaluated whether the radiation dose during peripheral arterial endovascular procedures had decreased after implementation of this new imaging system. Methods: The patient characteristics (age, gender, body mass index [BMI]), procedure type (diagnostic, balloon angioplasty, atherectomy, stenting), body location (aortoiliac, superficial femoral artery, tibial artery), reference air kerma (RAK), kerma area product (KAP), and fluoroscopy time (FT) were recorded during peripheral artery interventions performed 1 year before (group A) and 1 year after (group B) the CLEAR system upgrade. The procedures were performed in an Artis zeego hybrid room (Siemens Healthineers) with the same providers. A general linear model was used to estimate the average difference between groups adjusted by procedure type and patient age, gender, and BMI. Additionally, to control for variations in case complexity, groups A and B were matched by age, gender, BMI, lesion location, and intervention type. Propensity score matching and a paired t test were used to compare the KAP, RAK, and FT stratified by single intervention procedures. Results: A total of 487 endovascular procedures were performed: 209 in group A and 278 in group B. A total of 111 single intervention procedures from each group were matched (1:1), with a mean age of 61 +/- 8 years and a BMI of 26.5 +/- 4 kg/m(2). The median KAP, RAK, and FT for group A were 28.8 Gy . cm(2) (interquartile range [IQR], 24-34 Gy . cm(2)), 146 mGy (IQR, 123-173 mGy), and 12 minutes (IQR, 10-14 minutes), respectively. The median KAP, RAK, and FT for group B were 18.3 Gy . cm(2) (IQR, 16-22 Gy . cm(2)), 71.2 mGy (IQR, 60-85 mGy), and 10.4 minutes (IQR, 9-12 minutes), respectively. The KAP, RAK, and FT were significantly decreased in group B by 24% (P = .005), 41% (P <.001), and 22% ( P 1/4.002), respectively, compared with the values for group A. Stratified by single intervention procedures, the KAP and RAK had decreased significantly in group B (36% [P = .002] and 51% [P <.001], respectively) compared with group A. The FT decrease of 13% in group B was not statistically significant (P = .20). Conclusions: Use of the Clear VD11 PURE platform system (Siemens Healthineers) reduced the patient radiation dose by 51% during endovascular peripheral interventions. The similar FTs for the matched single intervention procedures before and after the upgrade indicated consistent case complexity and surgeon practice. This platform appears to be an effective system for lowering the radiation dose.

During the COVID-19 pandemic, communities faced two conflicting objectives: 1) minimizing infections among vulnerable populations with higher risk for severe illness and 2) enabling reopening to revive American livelihoods. The U.S. pandemic strategy myopically considered one objective at a time, with lockdowns that addressed the former, but was detrimental to the latter, and phased reopening that pursued the latter, but lost control over the former. How could we prioritize interventions to simultaneously minimize cases of severe illness and fatalities while reopening? A team of researchers anchored by the Center on Stochastic Modeling, Optimization, & Statistics (COSMOS), The University of Texas at Arlington, has formulated a computationally efficient optimization framework, referred to as COSMOS COVID-19 Linear Programming (CC19LP), to study the delicate balance between the expected fatality rate due to cases of severe illness and the level of normalcy in the community. The key to the CC19LP framework is a focus on "key contacts" that separate individuals at higher risk from the rest of the population. CC19LP minimizes expected fatalities by optimizing the use of available interventions, namely, COVID-19 testing, personal protective equipment (PPE), COVID-19 vaccines, and social precautions, such as distancing, handwashing, and face coverings. A C3.ai award-winning online CC19LP tool is accessible from the COSMOS COVID-19 project site ( https://cosmos.uta.edu/projects/covid-19/ ) and has been tested for all 3142 U.S. county areas. Results are demonstrated for several metropolitan counties with a deeper investigation for Miami-Dade County in Florida. Note to Practitioners —In this article, a computationally fast optimization framework is presented to study the delicate balance between reopening U.S. communities and controlling severe cases of COVID-19 that lead to hospitalizations and fatalities. This framework can provide guidance to decision-makers on optimal intervention strategies for protecting high-risk individuals while reopening communities. This optimization framework demonstrates a practical approach to conduct decision-making in an uncertain environment and can be useful for the prioritization of resources and interventions in the case of future epidemics or pandemics. Resources on understanding and implementing the framework are publicly available, including an award-winning online optimization tool that automatically accesses county-level data from Census, Centers for Disease Control and Prevention (CDC), and Johns Hopkins COVID-19 repositories.

OBJECTIVE:For fenestrated endovascular aneurysm repair (FEVAR), the implementation of the VesselNavigator (Philips Healthcare, Best, The Netherlands) to provide a 3-dimensional vessel roadmap has been shown to reduce patient radiation exposure. Unfortunately, FEVAR radiation doses remain substantial despite utilization of this technology. Traditionally, registration of the live fluoroscopy with the pre-operative CTA is performed via the acquisition of a low-dose cone-beam CT scan. However, this registration can also be accomplished with the acquisition of 2D X-rays using the c-arm in 2 different projection angles. We hypothesized that the 2D image acquisition for vessel roadmap development would result in a significant reduction in patient radiation dose in comparison to the 3D CT registration without compromising image quality or increasing procedural length.METHODS:This single-center, retrospective study included FEVARs performed from January 2015 to May 2019. For patient data, the cumulative reference air kerma (RAK) was presented as geometric mean and standard deviation. A general linear model with log-normal distribution was used to test the difference in patient RAK between 2D X-ray and 3D CT VesselNavigator registration after adjusting for BMI and the number of vessel fenestrations (1 to 2 vs. 3 to 4). Fluoroscopy time was recorded and used as a surrogate for case complexity. All analyses were done in SAS 9.4 (SAS Institute, Inc., Cary, North Carolina).RESULTS:One hundred and sixty four FEVARs were performed on a Philips Allura Xper FD 20 fluoroscopy system equipped with clarity technology. The VesselNavigator registration was completed using 3D CT mapping in 99 cases and 2D X-rays in 65 procedures. On average, utilization of 2D mapping versus 3D mapping for the VesselNavigator resulted in a 20.4% reduction in patient RAK after controlling for BMI and number of vessel fenestrations, P = 0.0135. There was no significant difference in fluoroscopy time between the 2 study groups (P= 0.81) suggesting that image quality was not compromised by the use of 2D mapping leading to the need for additional fluoroscopy.CONCLUSION:Acquisition of 2D films rather than a 3D CT scan for VesselNavigator registration allows for a significant reduction in patient radiation dose during FEVAR without increasing the case complexity or compromising image quality.

Objective: Long-term radiation exposure from fluoroscopically guided interventions (FGIs) can cause cataracts and brain tumors in the operator. We have previously demonstrated that leaded eyewear does not decrease the operator eye radiation dose unless lead shielding has been added to the lateral and inferior portions. Therefore, we have developed a disposable, lightweight, lead-equivalent shield that can be attached to the operator's eyewear that conforms to the face and adheres to the surgical mask. In the present study, we evaluated the efficacy of our new prototype in lowering the operator brain and eye radiation dose when added to both leaded and nonleaded eyewear. Methods: The attenuating efficacy of leaded eyewear alone, leaded eyewear plus the prototype, and nonleaded eyewear plus the prototype were compared with no eyewear protection in both a simulated setting and clinical practice. In the simulation, optically stimulated, luminescent nanoDot detectors (Landauer, Inc, Glenwood, Ill) were placed inside the ocular, temporal lobe, and midbrain spaces of a head phantom (ATOM model-701; CIRS, Norfolk, Va). The phantom was positioned to represent a primary operator performing right femoral access. Fluorography was performed on a plastic scatter phantom at 80 kVp for an exposure of 3 Gy reference air kerma. In the clinical setting, nanoDots were placed below the operator's eye both inside and outside the prototype during the FGIs. The median and interquartile ranges were calculated for the dose at each nanoDot location for the phantom and clinical studies. The average dose reduction was also recorded. Results: Wearing standard leaded eyewear alone did not decrease the operator ocular or brain radiation dose. In the phantom experiment, the leaded glasses plus the prototype reduced the radiation dose to the lens, temporal lobe, and midbrain by 83% (P < .001), 78% (P < .001), and 75% (P < .001), respectively. The nonleaded glasses plus the prototype also reduced the dose to the lens, temporal lobe, and midbrain by 85% (P < .001), 81% (P < .001), and 71% (P < .001), respectively. A total of 15 FGIs were included in the clinical setting, with a median reference air kerma of 98.4 mGy. The use of our prototype led to an average operator eye dose reduction of 89% (P < .001). Conclusions: Attaching our prototype to both leaded and nonleaded glasses significantly decreased the eye and brain radiation dose to the operator. This face shield attachment provided meaningful radiation protection and should be considered as either a replacement or an adjunct to routine eyewear.

Objective: Fenestrated-branched endovascular aneurysm repair (F/B-EVAR) is a complex procedure that generates high radiation doses. Magnification aids in vessel cannulation but increases radiation. The aim of the study was to compare radiation doses to patients and operating room staff from two fluoroscopy techniques, standard magnification vs dual fluoroscopy with live-image digital zooming during F/B-EVAR. Methods: An observational, prospective, single-center study of F/B-EVAR procedures using Philips Allura XperFD20 equipment (Philips Healthcare, Amsterdam, The Netherlands) was performed during a 42-month period. Intravascular ultrasound, three-dimensional fusion, and extreme collimation were used in all procedures. Intraoperative liveimage processing was performed with two imaging systems: standard magnification in 123 patients (81%) and dual fluoroscopy with live-image digital zooming in 28 patients (18%). In the latter, the live "processed" zoomed images are displayed on examination displays and live images are displayed on reference displays. The reference air kerma was collected for each case and represents patient dose. Operating staff personal dosimetry was collected using the DoseAware system (Philips Healthcare). Patient and staff radiation doses were compared using nonparametric tests. Results: Mean age was 71.6 +/- 11.4 years. The median body mass index was 27 kg/m(2) (interquartile range [IQR], 24.430.6 kg/m(2)) and was the same for both groups. Procedures performed with dual fluoroscopy with digital zooming demonstrated significantly lower median patient (1382 mGy [IQR, 999-2045 mGy] vs 2458 mGy [IQR, 1706-3767 mGy]; P <.01) and primary operator radiation doses (101 mu Sv [IQR, 34-235 mu Sv] vs 266 mu Sv [IQR, 104-583 mu Sv]; P <.01) compared with standard magnification. Similar significantly reduced radiation doses were recorded for first assistant, scrub nurse, and anesthesia staff in procedures performed with dual fluoroscopy. According to device design, procedures performed with four-fenestration/branch devices generated higher operator radiation doses (262 mu Sv [IQR, 116.5-572 mu Sv] vs 171 mu Sv [IQR, 44-325 mu Sv]; P <.01) compared with procedures with three or fewer fenestration/branches. Among the most complex design (four-vessel), operator radiation dose was significantly lower with digital zooming compared with standard magnification (128.5 mu Sv [IQR, 70.5-296 mSv] vs 309 mu Sv [IQR, 150-611 mu Sv]; P = .01). Conclusions: Current radiation doses to patients and operating personnel are within acceptable limits; however, dual fluoroscopy with live-image digital zooming results in dramatically lower radiation doses compared with the standard image processing with dose-dependent magnification. Operator radiation doses were reduced in half during procedures performed with more complex device designs when digital zooming was used.

Long-term radiation exposure from fluoroscopically guided interventions (FGIs) can cause cataracts and brain tumors in the operator. We have demonstrated that leaded eyewear does not decrease the operator eye dose unless lead shielding is added to the inferior portion. Therefore, we developed a disposable, lightweight, lead-equivalent shield that can be attached to the operator's eyewear, conforming around the face and adhering to the surgical mask. We evaluated the efficacy of our new prototype in lowering the operator brain and eye dose when added to both leaded and nonleaded eyewear. The attenuating efficacy of leaded eyewear alone, leaded eyewear plus the prototype, and nonleaded eyewear plus the prototype were compared to no eyewear protection in both a simulated setting and clinical practice. In the simulation, optically stimulated, luminescent nanoDot detectors (Landauer, Glenwood, Ill) were placed inside the ocular, temporal lobe, and midbrain spaces of a head phantom (ATOM model 701; CIRS, Norfolk, Va) and at the surface of the left eye within and outside the eyewear. The phantom was positioned to represent a primary operator. Fluorography was performed on a plastic scatter phantom at 80 kVp for an exposure of 3 Gy reference air kerma. In the clinical setting, nanoDots were placed below the operator's eyes, both inside and outside the prototype, during FGIs. The mean ± standard error was calculated using a pooled linear mixed model with repeated measurements. Wearing standard leaded eyewear alone did not decrease the operator's ocular or brain dose. In the phantom experiment, the prototype plus leaded glasses reduced the dose to the lens, temporal lobe, and midbrain by 83% (P < .001), 78% (P < .001), and 75% (P < .001), respectively. The prototype plus nonleaded glasses reduced the dose to the lens, temporal lobe, and midbrain by 85% (P < .001), 81% (P < .001), and 71% (P < .001), respectively (Fig). In the clinical setting, 15 FGIs were included, with a mean reference air kerma of 213 mGy. The mean operator eye dose outside the prototype was 249.3 μSv compared with 39.4 μSv inside, for an average dose reduction of 89% (P < .001). Attaching the prototype to both leaded and nonleaded glasses significantly decreased the eye and brain radiation dose to the operator. This face shield attachment provides meaningful radiation protection and should be considered as either a replacement or adjunct to routine leaded eyewear.

To compare radiation dose and image quality for abdominal CTs performed on a spectral detector CT (SDCT) and a comparable single-energy conventional CT scanner for patients of different sizes. Four semi-anthropomorphic phantoms were scanned on an SDCT (IQon, Philips Healthcare) and a comparable single-energy CT (iCT 256, Philips Healthcare) under matched scan parameters. Image noise and radiation dose were compared. For the HIPAA-compliant, IRB-approved retrospective cohort patient study, radiation dose was compared after adjusting for patient water equivalent diameter. Difference in subjective and objective image quality was assessed on a subset of 50 patients scanned on both scanners by two readers. CTDIvol and noise from SDCT were higher than conventional CT for all phantoms, with a relative difference of 7.8% (range 5.3–14%) for radiation dose and average difference of 9.0% (range 5.5–11%) for noise. 718 SDCT and 937 conventional CT patients were included in the patient study. CTDIvol for SDCT patients tends to be lower for smaller patients (− 2%, 95% confidence interval (− 5%, − 0.2%) for 200 mm water equivalent diameter) and higher for larger patients compared to conventional CT (8%, (6%, 11%) for 400 mm). No difference was seen for subjective image quality, SNR, CNR, or image noise between the two scanners, except for higher image noise in the portal vein and higher signal in the aorta on SDCT. Radiation dose for abdominal CT performed on SDCT is similar to the dose on a conventional CT for average size patients, lower for smaller patients, and slightly higher for larger patients. Image quality is similar between the two scanners.

BACKGROUND:Female gender is considered a risk factor for worse perioperative outcomes after fenestrated endovascular aneurysm repair (FEVAR). We hypothesized that women would have more unfavorable anatomy, increasing case complexity and leading to higher radiation doses. Our aim was to evaluate the effect of gender on radiation dose during FEVARs. METHODS:This single-center retrospective study was performed from 1/2015 to 2/2018. For patient data, linear model and stepwise variable selection algorithm were used. All dose measurements were log transformed before analysis. Significance level for parameter estimates and corresponding 95% confidence intervals were all transformed back using an exponential function. P-value of <0.05 was considered statistically significant. All analyses were performed in SAS 9.4 (SAS Institute Inc., Cary, NC). RESULTS:A total of 169 FEVARs (45 women) were performed on a Philips Allura Xper FD 20 fluoroscopy system equipped with clarity technology. There was no difference in body mass index (BMI) or operative time between genders, P = 0.9. The median reference air kerma for women was significantly lower than that for men (1,672 mGy vs. 2,496 mGy), P < 0.001. Women had on average a 28% total dose reduction after controlling for BMI, number of vessels fenestrated, operative time, and type of device, P < 0.001. The median fluorography and fluoroscopy doses for women were significantly lower than those for men (973 mGy vs. 1,401 mGy and 659 mGy vs. 1,008 mGy), resulting in a 24% fluorography dose reduction and a 38% fluoroscopy dose reduction for women, P < 0.001. CONCLUSIONS:FEVARs can be performed successfully in women with comparatively lower radiation doses.

Objective: Ocular radiation exposure from fluoroscopically guided interventions (FGIs) can cause cataracts. Standard lead eyewear may not significantly reduce eye radiation dose as the majority of scattered radiation penetrates the operator's eye obliquely. Our aim was to evaluate the efficacy of standard leaded eyewear and a customized eyewear design in lowering eye radiation dose to vascular surgeons. Methods: The attenuating efficacy of three forms of leaded eyewear (standard eyewear, eyewear with built-in leaded side shields, and our modified eyewear) was tested in both a simulated setting and clinical practice. The modified design consisted of safety eyewear with 0.75 mm of added lead shielding attached to the lateral and inferior borders of the eyewear frame to attenuate oblique radiation. We performed simulated experiments using an anthropomorphic head phantom (ATOM model 701; CIRS, Norfolk, Va) positioned to represent a primary operator performing right femoral access. Optically stimulated, luminescent nanoDot detectors (Landauer, Glenwood, Ill) were placed inside the phantom's ocular spaces and at the surface of the left eye within and outside the leaded glasses to measure the eye radiation dose reduction provided by each eyewear type. All three eyewear types were also tested during clinical FGIs by placing nanoDots below the operator's left eye, inside and outside of the eyewear coverage. Means and standard errors were calculated using a pooled linear mixed model with repeated measurements. Results: This prospective, single-center study included 60 FGIs, 30 with traditional eyewear and 30 with our modified design. There was no significant eye radiation dose reduction (P>.05) with the standard eyewear or leaded side shield eyewear in both the simulated and clinical settings. In the simulated environment, our modified design resulted in an 86% radiation dose reduction to the surface of the left eye and an 80% reduction in left lens radiation dose (P < .0001). In the clinical FGIs, the modified eyewear led to a 62% left ocular radiation dose reduction (P < .0001). Conclusions: Standard lead-equivalent glasses are ineffective at reducing ocular radiation dose during FGIs. Eyewear modification with lateral and inferior lead shielding molded to the operator's face significantly decreases radiation exposure to the eye closest to the X-ray source.

AbstractAs communities reopen following shelter-in-place orders, they are facing two conflicting objectives. The first is to keep the COVID-19 fatality rate down. The second is to revive the U.S. economy and the livelihood of millions of Americans. In this paper, a team of researchers from the Center on Stochastic Modeling, Optimization, & Statistics (COSMOS) at the University of Texas at Arlington, in collaboration with researchers from University of Texas Southwestern Medical Center and Harvard Medical School, has formulated a computationally-efficient optimization framework, referred to as COSMOS COVID-19 Linear Programming (CC19LP), to study the delicate balance between the expected fatality rate and the level of normalcy in the community. Given the disproportionate fatality characteristics of COVID-19 among those in different age groups or with an underlying medical condition or those living with crowding, the key to the CC19LP framework is a focus on “key contacts” that separate individuals at higher risk from the rest of the population. The philosophy of CC19LP lies in maximizing protection of key contacts, so as to shield high-risk individuals from infection. Given the lack of pharmaceutical solutions, i.e., a vaccine or cure, the CC19LP framework minimizes expected fatalities by optimizing the use of non-pharmaceutical interventions, namely COVID-19 testing; personal protective equipment; and social precautions, such as distancing, hand-washing, and face coverings. Low-risk individuals that are not key contacts, including most children, are unrestricted and can choose to participate in pre-pandemic normal activities, which eliminates the need for compliance across the entire population. Consequently, the CC19LP framework demonstrates optimal strategies for protecting high-risk individuals while reopening communities.

PURPOSE:To present our experience in reducing CT radiation doses in a complex tertiary health system through CT protocol standardization and optimization.METHODS:A CT radiation task force was created to reduce CT protocol heterogeneity and radiation doses. Redundant protocols were eliminated. By an iterative process, protocols with least radiation dose were identified. Radiation dose tracking software was used to store and analyze radiation doses. CT protocols were published in an intranet site after training of technologists. SOPs were established for maintaining and changing protocols. The radiation doses for each CT protocol before and after optimization were compared using geometric means.RESULTS:A total of 222 CT protocols were reviewed, with elimination of 86 protocols. One-year follow-up showed homogeneous protocols with lower radiation doses. The improvement in radiation doses ranged from 23% to 58% (P< 0.001).CONCLUSION:CT radiation dose reduction of up to 58% can be achieved by homogenizing and optimizing CT protocols through a comprehensive CT operations program.

A rapidly converging, iterative deconvolution algorithm with a novel resolution subsets-based approach RSEMD that operates on digital imaging and communications in medicine images to improve the quality of clinical CT images is presented. The RSEMD method was tested on Catphan 500 and anthropomorphic 4-D XCAT phantoms to determine the improvements in signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). The method was applied to preclinical CT images previously reconstructed by conventional software. To test the potential improvement in clinically relevant CT images we employed the 4-D XCAT phantom to simulate a small, low contrast lesion placed in the liver. In all of the phantom studies, the images proved to have higher resolution and lower noise as compared with filtered back projection. In general, the iterative deblurring restoration reaches the highest SNR and CNR values after approximately 20 iterations with an improvement factor of about 1.5 for both CNR and SNR in noisy CT images. We also found improvements in preclinical and clinical CT images after the application of RSEMD. The results obtained with the RSEMD method are in agreement with other iterative algorithms employed either in image space or with hybrid reconstruction algorithms which start in projection space and then follow in image domain. The RSEMD method can be applied to suboptimal routine-dose clinical CT images to improve the image quality to diagnostically acceptable levels.