Patient Radiation Dose Research Articles

Towards the establishment of national diagnostic reference levels for abdomen, KUB, and lumbar spine x-ray examinations in Sri Lanka: a multi-centric study

Diagnostic reference levels (DRLs) and achievable doses (ADs) provide guidance to optimise radiation doses for patients undergoing medical imaging procedures. This multi-centre study aimed to compare institutional DRLs (IDRLs) across hospitals, propose ADs and multi-centric DRLs (MCDRLs) for four common x-ray examinations in Sri Lanka, and assess the potential for dose reduction. A prospective cross-sectional study of 894 adult patients referred for abdomen anteroposterior (AP), kidney-ureter-bladder (KUB) AP, lumbar spine AP, and lumbar spine lateral (LAT) x-ray examinations was conducted. Patient demographic information (age, sex, weight, BMI) and exposure parameters (tube voltage, tube current-exposure time product) were collected. Patient dose indicators were measured in terms of kerma-area product (PKA) using a PKA meter. IDRLs, ADs, and MCDRLs were calculated following the International Commission on Radiological Protection guidelines, with ADs and MCDRLs defined as the 50th and 75th percentiles of the median PKA distributions, respectively. IDRL ranges varied considerably across hospitals: 1.42–2.42 Gy cm2 for abdomen AP, 1.51–2.86 Gy cm2 for KUB AP, 0.83–1.65 Gy cm2 for lumbar spine AP, and 1.76–4.10 Gy cm2 for lumbar spine LAT. The proposed ADs were 1.82 Gy cm2 (abdomen AP), 2.03 Gy cm2 (KUB AP), 1.27 Gy cm2 (lumbar spine AP), and 2.21 Gy cm2 (lumbar spine LAT). MCDRLs were 2.24 Gy cm2 (abdomen AP), 2.40 Gy cm2 (KUB AP), 1.43 Gy cm2 (lumbar spine AP), and 2.38 Gy cm2 (lumbar spine LAT). Substantial intra- and inter-hospital variations in PKA were observed for all four examinations. Although ADs and MCDRLs in Sri Lanka were comparable to those in the existing literature, the identified intra- and inter-hospital variations underscore the need for dose reduction without compromising diagnostic information. Hospitals with high IDRLs are recommended to review and optimise their practices. These MCDRLs serve as preliminary national DRLs, guiding dose optimisation efforts by medical professionals and policymakers.

Post-radiation middle ear effusion in NPC patients: Analysis of patient, tumour, and radiation factors.

The purpose of this study was to investigate whether patient, tumour and radiation therapy factors are associated with development of middle ear effusion (MEE) in nasopharyngeal carcinoma (NPC) patients. A retrospective review of NPC patients treated between January 2000 and June 2018 at Rabin Medical Center. Patient factors, tumour factors, radiation doses, and radiation fields were collected and outlined if needed (middle ear, eustachian tube [ET], tensor veli palatini [TVP], and levator palatini [LVP] muscles), then analysed and compared between patients with MEE and those without and between sides in patients with unilateral MEE. Seventy-three patients were enrolled. Most were males (71.2%) with advanced-stage diseases (78%). At the time of diagnosis 14 patients (19.2%) presented with MEE. Following radiation, 18 patients, with no evidence of MEE at presentation, developed MEE. Tumour stage, histology, and laterality were not associated with development of MEE. Comparison of mean radiation field dosages including-gross target volume, clinical target volume, and patient target volume showed no association with post-radiation MEE. In addition, no difference was found in the radiation doses to the middle ear, ET or the LVP nor the TVP between ears with and without MEE. Post-irradiation MEE remains a common adverse effect in NPC patients. Surprisingly, tumour stage, tumour laterality, and histology were not associated with MEE. Similar findings were observed for total radiation doses and specific doses to the middle ear, ET, and ET muscles.

Comparing Radiation Doses in CBCT and Medical CT Imaging for Dental Applications.

Dental imaging plays a crucial role in diagnosis and treatment planning, with cone-beam computed tomography (CBCT) and medical computed tomography (CT) being two common modalities. This study aims to compare the radiation doses associated with CBCT and medical CT imaging in dental applications to assess their relative safety and efficacy. We conducted a retrospective study using data from 100 patients who underwent both CBCT and medical CT scans for dental purposes. The radiation doses were measured in terms of dose-length product (DLP) for medical CT and dose-area product (DAP) for CBCT. The effective dose (ED) was calculated using appropriate conversion factors. Patient demographics, scan parameters, and radiation doses were recorded and analyzed. The results indicated that the mean DLP for medical CT scans was 220 mGycm, whereas the mean DAP for CBCT scans was 150 mGycm². The corresponding mean effective doses for medical CT and CBCT were 2.5 mSv and 1.8 mSv, respectively. The radiation dose from CBCT was found to be approximately 28% lower than that from medical CT. This study demonstrates that CBCT imaging for dental applications results in significantly lower radiation doses compared to medical CT. While both modalities provide valuable diagnostic information, the choice of imaging technique should consider the balance between diagnostic quality and radiation exposure, especially for pediatric and high-risk patients. Dental practitioners should be aware of the potential dose reduction benefits associated with CBCT when appropriate for the clinical scenario.

Intraoperative Cone-Beam Computed Tomography Navigation Versus 2-Dimensional Fluoroscopy in Single-Level Lumbar Spinal Fusion: A Comparative Analysis.

Several studies have advocated for the higher accuracy of transpedicular screw placement under cone-beam computed tomography (CBCT) compared to conventional 2-dimensional (2D) fluoroscopy. The superiority of navigation systems in perioperative and postoperative outcomes remains a topic of debate. This study aimed to compare operative time, screw placement time and accuracy, total radiation dose, perioperative and postoperative outcomes in patients who underwent transpedicular screw fixation for degenerative lumbar spondylolisthesis (DLS) using intraoperative CBCT navigation versus 2D fluoroscopy. A retrospective analysis was conducted on patients affected by single-level DLS who underwent posterior lumbar instrumentation with transpedicular screw fixation using surgical CBCT navigation (NV group) or 2D fluoroscopy-assisted freehand technique (FH group). Demographics, screw placement time and accuracy, operative time, total radiation dose, intraoperative blood loss, screw revision rate, complications, and length of stay (LOS) were assessed. The study included a total of 30 patients (NV group: n = 15; FH group: n = 15). The mean screw placement time, operative time, and LOS were significantly reduced in the NV group compared to the FH group (p < 0.05). The total radiation dose was significantly higher in the NV group (p < 0.0001). No significant difference was found in terms of blood loss and postoperative complications. This study suggests that intraoperative CBCT-navigated single-level lumbar transpedicular screw fixation is superior in terms of mean screw placement time, operative time, and LOS compared to 2D fluoroscopy, despite a higher intraoperative radiation exposure.

갑상선 CT에서 스캔 파라메터 변화에 따른 선속 경화 현상 저감에 관한 연구

The beam hardening artifact arising from complex shoulder structures in thyroid CT makes it difficult to capture anatomical fine details. Thus, the purpose of our study was to know appropriate scan parameters to reduce artifacts without significantly increasing the radiation dose. We utilized the GE Revolution APEX equipment for this study. We conducted the thyroid CT examinations by varying the thickness to 0.625 mm, 1.25 mm, and 2.5 mm, and adjusting the maximum mA to 300 mA, 600 mA, and 900 mA while applying auto exposure control system. The radiation dose was measured using a glass dosimeter placed at the thyroid location of the RANDO phantom. We measured signal to noise ratio (SNR) and contrast to noise ratio (CNR) of the experimental images to analyze the image quality of the thyroid area. As the slice thickness increases, the experimental dose also increases. The same pattern was observed for the maximum tube current. In terms of SNR, there is no difference between a slice thickness of 0.625 mm and 1.25 mm. However, there is a difference between measurements of 0.625 mm and 2.5 mm, and the same for 1.25 mm and 2.5 mm. No difference was observed in terms of tube current variations. The analysis of CNR reveals that there is not a significant difference as slice thickness and maximum tube current change. To improve quality of the images in complex shoulder structures, adjusting the scan parameters of thyroid CT affects not only SNR but also patient's radiation dose. Analyzing image quality through SNR showed that increasing the slice thickness improved the image quality. However, We should carefully use changes in parameters because the increase in slice thickness also involves an increase in radiation dose.

Evaluation of 3D C-Arm Fluoroscopy versus Diagnostic CT for Deep Brain Stimulation Stereotactic Registration and Post-Operative Lead Localization

Introduction: DBS efficacy depends on accuracy. CT-MRI fusion is established for both stereotactic registration and electrode placement verification. The desire to streamline DBS workflows, reduce operative time, and minimize patient transfers has increased interest in portable imaging modalities such as the Medtronic O-arm® and mobile CT. However, these remain expensive and bulky. 3D C-arm fluoroscopy (3DXT) units are a smaller and less costly alternative, albeit incompatible with traditional frame-based localization and without useful soft tissue resolution. We aimed to compare fusion of 3DXT and CT with pre-operative MRI to evaluate if 3DXT-MRI fusion alone is sufficient for accurate registration and reliable targeting verification. We further assess DBS targeting accuracy using a 3DXT workflow and compare radiation dosimetry between modalities. Methods: Patients underwent robot-assisted DBS implantation using a workflow incorporating 3DXT which we describe. Two intra-operative 3DXT spins were performed for registration and accuracy verification followed by conventional CT post-operatively. Post-operative 3DXT and CT images were independently fused to the same pre-operative MRI sequence and co-ordinates generated for comparison. Registration accuracy was compared to 15 consecutive controls who underwent CT-based registration. Radial targeting accuracy was calculated and radiation dosimetry recorded. Results: Data were obtained from 29 leads in 15 consecutive patients. 3DXT registration accuracy was significantly superior to CT with mean error 0.22 ± 0.03 mm (p < 0.0001). Mean Euclidean electrode tip position variation for CT to MRI versus 3DXT to MRI fusion was 0.62 ± 0.40 mm (range 0.0 mm–1.7 mm). In comparison, direct CT to 3DXT fusion showed electrode tip Euclidean variance of 0.23 ± 0.09 mm. Mean radial targeting accuracy assessed on 3DXT was 0.97 ± 0.54 mm versus 1.15 ± 0.55 mm on CT with differences insignificant (p = 0.30). Mean patient radiation doses were around 80% lower with 3DXT versus CT (p < 0.0001). Discussion: Mobile 3D C-arm fluoroscopy can be safely incorporated into DBS workflows for both registration and lead verification. For registration, the limited field of view requires the use of frameless transient fiducials and is highly accurate. For lead position verification based on MRI co-registration, we estimate there is around a 0.4 mm discrepancy between lead position seen on 3DXT versus CT when corrected for brain shift. This is similar to that described in O-arm® or mobile CT series. For units where logistical or financial considerations preclude the acquisition of a cone beam CT or mobile CT scanner, our data support portable 3D C-arm fluoroscopy as an acceptable alternative with significantly lower radiation exposure.

Assessing Patient Radiation Exposure in Endoscopic Retrograde Cholangiopancreatography: A Multicenter Retrospective Analysis of Procedural Complexity and Clinical Factors.

Endoscopic retrograde cholangiopancreatography (ERCP) procedures can result in significant patient radiation exposure. This retrospective multicenter study aimed to assess the influence of procedural complexity and other clinical factors on radiation exposure in ERCP. Data on kerma-area product (KAP), air-kerma at the reference point (Ka,r), fluoroscopy time, and the number of exposures, and relevant patient, procedure, and operator factors were collected from 2641 ERCP procedures performed at four university hospitals. The influence of procedural complexity, assessed using the American Society for Gastrointestinal Endoscopy (ASGE) and HOUSE complexity grading scales, on radiation exposure quantities was analyzed within each center. The procedures were categorized into two groups based on ERCP indications: primary sclerosing cholangitis (PSC) and other ERCPs. Both the ASGE and HOUSE complexity grading scales had a significant impact on radiation exposure quantities. Remarkably, there was up to a 50-fold difference in dose quantities observed across the participating centers. For non-PSC ERCP procedures, the median KAP ranged from 0.9 to 64.4 Gy·cm2 among the centers. The individual endoscopist also had a substantial influence on radiation dose. Procedural complexity grading in ERCP significantly affects radiation exposure. Higher procedural complexity is typically associated with increased patient radiation dose. The ASGE complexity grading scale demonstrated greater sensitivity to changes in radiation exposure compared to the HOUSE grading scale. Additionally, significant variations in dose indices, fluoroscopy times, and number of exposures were observed across the participating centers.

Comparison of a Patient-Mounted Needle-Driving Robotic System versus Single-Rotation CT Fluoroscopy to Perform CT-Guided Percutaneous Lung Biopsies

PurposeTo compare the effectiveness of percutaneous lung biopsy using a patient-mounted needle-driving robotic system with that using a manual insertion of needles under computed tomography (CT) fluoroscopy guidance. Materials and MethodsIn this institutional review board approved study, the cohort consisted of a series of patients who underwent lung biopsies following the intention-to-treat protocol from September 2022 to September 2023 using robot (n = 15) or manual insertion under single-rotation CT fluoroscopy (n = 66). Patient and procedure characteristics were recorded as well as outcomes. ResultsAlthough age, body mass index, and skin-to-target distance were not statistically different, target size varied (median, 8 mm [interquartile range, 6.5–9.5 mm] for robot vs 12 mm [8–18 mm] for single-rotation CT fluoroscopy; P = .001). No statistical differences were observed in technical success (86.7% [13/15] vs 89.4% [59/66], P = .673), Grade 3 adverse event (AE) (6.7% [1/15] vs 12.1% [8/66], P = .298), procedural time (28 minutes [22–32 minutes] vs 19 minutes [14.3–30.5 minutes], P = .086), and patient radiation dose (3.9 mSv [3.2–5.6 mSv] vs 4.6 mSv [3.3–7.5 mSv], P = .398). In robot-assisted cases, the median angle out of gantry plane was 10° (6.5°–16°), although it was null (0°–5°) for single-rotation CT fluoroscopy (P = .001). ConclusionsRobot-assisted and single-rotation CT fluoroscopy–guided percutaneous lung biopsies were similar in terms of technical success, diagnostic yield, procedural time, AEs, and radiation dose, although robot allowed for out-of-gantry plane navigation along the needle axis.

National-level Dental Radiological Dose Management

There is growing public concern about patients' radiation exposure from recent medical imaging using ion-izing radiation. While medical radiation exposure has inevitable aspects, efforts to optimize doses in line with the principles of justification and optimization are necessary to maximize diagnostic value with the minimumradiation dose. Diagnostic reference levels have been proposed as a means to achieve optimization, in accordance with ICRP (International Commission on Radiological Protection) publications 60 and 73, as well as EC (European Commission) Directive 97/43/Euratom. According to Requirement 34 of the 'InternationalBasic Safety Standards' published by the IAEA in 2014, governments are recommended to establish national diagnostic reference levels. According to ICRP Publication 135, issued in 2017, national diagnostic reference levels should be revised regularly, preferably every 3-5 years, and more frequently in the case of technologicaladvancements, such as in the case of CBCT. In South Korea, diagnostic reference levels for various imagingmodalities have been established since 2007. In the field of dentistry, diagnostic reference levels for intraoral and panoramic radiography were established in 2009, and in 2018, diagnostic reference levels for dental CBCT were introduced for the first time. The purpose of this report is to discuss the current national-level patient radia-tion dose management in South Korea and explore its applications

Radioactive seed localization is a safe and effective tool for breast cancer surgery: an evaluation of over 25,000 cases.

Radioactive seed localization (RSL) provides a precise and efficient method for removing non-palpable breast lesions. It has proven to be a valuable addition to breast surgery, improving perioperative logistics and patient satisfaction. This retrospective review examines the lessons learned from a high-volume cancer center's RSL program after 10 years of practice and over 25 000 cases. We provide an updated model for assessing the patient's radiation dose from RSL seed implantation and demonstrate the safety of RSL to staff members. Additionally, we emphasize the importance of various aspects of presurgical evaluation, surgical techniques, post-surgical management, and regulatory compliance for a successful RSL program. Notably, the program has reduced radiation exposure for patients and medical staff.

Implementasi Pemahaman Radiografer terhadap Exposure Index dalam Optimasi Prosedur Pemeriksaan Radiografi Computed Radiography

Background: Increasing the exposure factor is often carried out by radiographers to reduce noise and maintain image quality in computer radiography (CR). Therefore, there is a need for awareness and understanding of the exposure index (EI) to implement optimization procedures in radiographic examinations. Methods: The research method is descriptive and analytical by providing questionnaires to radiographers in PA chest radiographic examinations. This research was carried out at hospitals A, B, and C in the Jakarta-Bogor area with the research carried out between August – October 2023. Statistical analysis used SPSS 27 with data coding previously. After that, the data is processed with descriptive statistics to determine the frequency, distribution, percentage, average, and standard deviation. Then, the test chi-square to determine the relationship between gender, age, education, and work experience in understanding CR optimization procedures. Next, to find out the relationship between age and weight and EI, a test was carried out by Pearson test to determine the level of relationship between the two variablesResults: was found that the level of awareness and understanding of radiographers regarding optimization procedures using EI is still low. Test results chi-square age-understanding 0.309, gender-understanding 0.772, education-understanding 0.036, experience-understanding 0.201. next are the test results Pearson for Hospital-A: age-EI 0.09, weight-EI -0.49, Hospital-B: age-EI -0.21, weight-EI 0.06, Hospital-C: age-EI -0.37, weight-EI 0.56. Conclusions: implementing EI in the optimization procedure, it needs to be confirmed by measuring the patient's radiation dose so that there are no errors in implementing the optimization.

Analyzer-free hard x-ray interferometry

Objective. To enable practical interferometry-based phase contrast CT using standard incoherent x-ray sources, we propose an imaging system where the analyzer grating is replaced by a high-resolution detector. Since there is no need to perform multiple exposures (with the analyzer grating at different positions) at each scan angle, this scheme is compatible with continuous-rotation CT apparatus, and has the potential to reduce patient radiation dose and patient motion artifacts. Approach. Grating-based x-ray interferometry is a well-studied technique for imaging soft tissues and highly scattering objects embedded in such tissues. In addition to the traditional x-ray absorption-based image, this technique allows reconstruction of the object phase and small-angle scattering information. When using conventional incoherent, polychromatic, hard x-ray tubes as sources, three gratings are usually employed. To sufficiently resolve the pattern generated in these interferometers with contemporary x-ray detectors, an analyzer grating is used, and consequently multiple images need to be acquired for each view angle. This adds complexity to the imaging system, slows image acquisition and thus increases sensitivity to patient motion, and is not dose efficient. By simulating image formation based on wave propagation, and proposing a novel phase retrieval algorithm based on a virtual grating, we assess the potential of a analyzer-grating-free system to overcome these limitations. Main results. We demonstrate that the removal of the analyzer-grating can produce equal image contrast-to-noise ratio at reduced dose (by a factor of 5), without prolonging scan duration. Significance. By demonstrating that an analyzer-free CT system, in conjuction with an efficient phase retrieval algorithm, can overcome the prohibitive dose and workflow penalties associated grating-stepping, an alternative path towards realizing clinical inteferometric CT appears possible.

Statewide Initiative to Reduce Patient Radiation Doses During Percutaneous Coronary Intervention.

Improved radiation safety practices are needed across hospitals performing percutaneous coronary intervention (PCI). This study was performed to assess the temporal trend in PCI radiation doses concurrent with the conduct of a statewide radiation safety initiative. A statewide initiative to reduce PCI radiation doses was conducted in Michigan between 2017 and 2021 and included focused radiation safety education, reporting of institutional radiation doses, and implementation of radiation performance metrics for hospitals. Using data from a large statewide registry, PCI discharges between July 1, 2016, and July 1, 2022, having a procedural air kerma (AK) recorded were analyzed for temporal trends. A multivariable regression analysis was performed to determine whether declines in procedural AK over time were attributable to changes in known predictors of radiation doses. Among 131 619 PCI procedures performed during the study period, a reduction in procedural AK was observed over time, from a median dose of 1.46 (0.86-2.37) Gy in the first year of the study to 0.97 (0.56-1.64) Gy in the last year of the study (P<0.001). The proportion of cases with an AK ≥5 Gy declined from 4.24% to 0.86% over the same time period (P<0.0001). After adjusting for variables known to impact radiation doses, a 1-year increase in the date of PCI was associated with a 7.61% (95% CI, 7.38%-7.84%) reduction in procedural AK (P<0.0001). Concurrent with the conduct of a statewide initiative to reduce procedural radiation doses, a progressive and significant decline in procedural radiation doses was observed among patients undergoing PCI in the state of Michigan.

Factors associated with cavity formation after stereotactic body radiation therapy for peripheral early-stage lung cancer.

This retrospective study aimed to identify the factors associated with cavity formation after SBRT in peripheral early-stage lung cancer patients. We analyzed the occurrence of cavity changes after SBRT. We examined 99 cases with T1-T2aN0 peripheral non-small cell lung cancer treated with SBRT from 2004 to 2021. Patients underwent respiratory function tests, including diffusing capacity for carbon monoxide (DLco), before treatment. The median observation period was 35months (IQR 18-47.5months). Treatment involved fixed multi-portal irradiation in 67% of cases and VMAT in 33%. The total radiation doses ranged from 42 to 55Gy, delivered over 4 to 5 fractions. Cavity formation occurred in 14 cases (14.1%), appearing a median of 8months after SBRT. The cavity disappeared in a median of 4months after formation. High DLco and total radiation dose were identified as factors significantly associated with cavity formation. There have been no confirmed recurrences to date, but one patient developed a lung abscess. Although cavity formation after SBRT for peripheral early-stage lung cancer is infrequent, it can occur. This study showed high DLco and total radiation dose to be factors significantly associated with cavity formation. These findings can be applied to optimizing radiation therapy (RT) and improving patient outcomes. Further research is needed to determine the optimal radiation dose for patients with near-normal DLco for whom surgery is an option. This study provides valuable insights into image changes after RT.

Analysis of Computed Tomography Dose Index (CTDI) And Dose Length Product (DLP) Dose Values On Non-Contrast Head, Chest And Abdominal CT Scan Examination At RSUD Ulin Banjarmasin

Background: CT scans produce the largest dose of radiation compared to other radiology modalities. The parameters for measuring the amount of radiation dose from the CT Scan aircraft are the Computed Tomography Dose Index (CTDI) and the Dose Lenght Product (DLP). One form of Bapeten supervision in controlling radiation protection is to optimize the Diagnostic Raference Level (DRL). At RSUD Ulin Banjarmasin, the CT Scan modality has never been measured for CT Scan dose on CT Scan examination of the Head, Thorax and Abdomen Non Contrast which are the most frequent examinations. Dosage parameters are important to see the values exposed to the patient. The purpose of this study was to determine the amount of radiation dose of patients on CT Scan examination of the Head, Thorax and Non-Contrasting Abdomen. Method: The research design used is quantitative descriptive. The method of collecting data is observational and uses secondary data. Data processing uses the descriptive hypothesis test method one sample t-test, by analyzing the value of radiation dose and comparing the DRL value set by Bapeten as a means to monitor the dose given α=0.05. Results: Dose values for CT Scan of Non Contrast Head 33.90±3.66 mGy for CTDIvol and 933.07±415.63 mGy.cm for DLP. CT Scan Thorax Non Contrast 5.83±1.90 mGy for CTDIvol and 179.80±63.72 mGy.cm for DLP. Non Contrast Abdominal CT Scan 10.88±2.30 mGy for CTDIvol and 528.70±137.75 mGy.cm for DLP. Conclusion: The dose value at RSUD Ulin Banjarmasin in each CT Scan examination of the Head, Thorax and Abdomen Non Contrast is still below the National DRL value set by BAPETEN.

Evaluation of radiation dose and radiation-induced cancer risk associated with routine CT scan examinations

Using patient-specific data, the present study aimed to identify organ and effective dose to estimate the lifetime attributable risks (LARs) of cancer incidence and mortality associated with routine CT procedures. A cross-sectional investigation was conducted on 515 patients who underwent CT scan. The effective dose was computed using two methods: first, the ImPACT software and relevant conversion factors. Second, the effective dose was determined using the scanner-derived DLP and AAPM TG 23's conversion factor. Using the biological effects of ionizing radiation (BEIR VII) report, LAR of cancer incidence and mortality were computed. The greatest mean organ doses for abdomen-pelvis, routine chest, chest HRCT, brain, and sinus examinations were 20.64 ± 3.27 mGy (kidneys), 21.55 ± 5.47 mGy (thymus and esophagus), 10.51 ± 1.31 mGy (thymus and esophagus), 22.72 ± 3.01 mGy (lens), and 18.56 ± 1.25 mGy (lens) respectively. Using ImPACT dosimetry software, the mean effective dose for routine chest, abdomen-pelvis, HRCT chest, brain, and sinus examinations was 8.46 mSv, 10.13 mSv, 4.19 mSv, 1 mSv, and 0.68 mSv, respectively. Using the DLP to effective dose conversion factor, the mean effective dose was lower. The mean cancer incidence risks per 100,000 people were 63.33, 54.98, 27.82, 6.31, and 5.22 for abdomen-pelvis, routine chest, HRCT, brain, and sinus examinations, respectively. The mean LAR of cancer mortality for all cancer was 38.22, 33.17, 16.72, 3.87, 2.93 for abdomen-pelvis, routine chest, HRCT, brain, and sinus examinations, respectively, per 100,000 people. Thus, CT scan exams are connected with a non-negligible risk of cancer, and patient radiation dose must be optimized to limit radiation risk.

Impact of point-of-care clinical decision support on referrer behavior, imaging volume, patient radiation dose exposure, and sustainability

ObjectivesWhen referring patients to radiology, it is important that the most appropriate test is chosen to avoid inappropriate imaging that may lead to delayed diagnosis, unnecessary radiation dose, worse patient outcome, and poor patient experience. The current radiology appropriateness guidance standard at our institution is via access to a standalone web-based clinical decision support tool (CDST). A point-of-care (POC) CDST that incorporates guidance directly into the physician workflow was implemented within a subset of head and neck cancer specialist referrers. The purpose of this audit was to evaluate the imaging pathway, pre- and post-implementation to assess changes in referral behavior.MethodsCT and MRI neck data were collected retrospectively to examine the relationship between imaging referrals pre- and post-POC CDST implementation. Effective radiation dose and estimated carbon emissions were also compared.ResultsThere was an overall reduction in absolute advanced imaging volume by 8.2%, and a reduction in duplicate CT and MRI imaging by 61%, p < 0.0001. There was also a shift in ordering behavior in favor of MRI (OR [95% CI] = 1.50 [1.02–2.22], p = 0.049). These changes resulted in an effective radiation dose reduction of 0.27 mSv per patient, or 13 equivalent chest x-rays saved per patient, p < 0.0001. Additionally, the reduction in unnecessary duplicate imaging led to a 13.5% reduction in carbon emissions, p = 0.0002.ConclusionsImplementation of the POC CDST resulted in a significant impact on advanced imaging volume, saved effective dose, and reduction in carbon emissions.Critical relevance statementThe implementation of a point-of-care clinical decision support tool may reduce multimodality ordering and advanced imaging volume, manifesting in reduced effective dose per patient and reduced estimated carbon emissions. Widespread utilization of the point-of-care clinical decision support tool has the potential to reduce imaging wait times.Key points• Implementation of the point-of-care clinical decision support tool reduced the number of patients who simultaneously had a CT and MRI ordered for the same clinical indication compared to a standalone web-based clinical decision support tool.• The point-of-care clinical decision support tool reduced the absolute number of CT/MRI scans requested compared to the standalone web-based clinical decision support tool.• Utilization of the point-of-care clinical decision support tool led to a significant reduction in the effective dose per patient compared to the standalone web-based clinical decision support tool.Graphical

Photon-Counting Detector CT for Liver Lesion Detection-Optimal Virtual Monoenergetic Energy for Different Simulated Patient Sizes and Radiation Doses.

The aim of this study was to evaluate the optimal energy level of virtual monoenergetic images (VMIs) from photon-counting detector computed tomography (CT) for the detection of liver lesions as a function of phantom size and radiation dose. An anthropomorphic abdominal phantom with liver parenchyma and lesions was imaged on a dual-source photon-counting detector CT at 120 kVp. Five hypoattenuating lesions with a lesion-to-background contrast difference of -30 HU and -45 HU and 3 hyperattenuating lesions with +30 HU and +90 HU were used. The lesion diameter was 5-10 mm. Rings of fat-equivalent material were added to emulate medium- or large-sized patients. The medium size was imaged at a volume CT dose index of 5, 2.5, and 1.25 mGy and the large size at 5 and 2.5 mGy, respectively. Each setup was imaged 10 times. For each setup, VMIs from 40 to 80 keV at 5 keV increments were reconstructed with quantum iterative reconstruction at a strength level of 4 (QIR-4). Lesion detectability was measured as area under the receiver operating curve (AUC) using a channelized Hotelling model observer with 10 dense differences of Gaussian channels. Overall, highest detectability was found at 65 and 70 keV for both hypoattenuating and hyperattenuating lesions in the medium and large phantom independent of radiation dose (AUC range, 0.91-1.0 for the medium and 0.94-0.99 for the large phantom, respectively). The lowest detectability was found at 40 keV irrespective of the radiation dose and phantom size (AUC range, 0.78-0.99). A more pronounced reduction in detectability was apparent at 40-50 keV as compared with 65-75 keV when radiation dose was decreased. At equal radiation dose, detection as a function of VMI energy differed stronger for the large size as compared with the medium-sized phantom (12% vs 6%). Detectability of hypoattenuating and hyperattenuating liver lesions differed between VMI energies for different phantom sizes and radiation doses. Virtual monoenergetic images at 65 and 70 keV yielded highest detectability independent of phantom size and radiation dose.

Clinical application of intravascular forceps biopsy in the diagnosis of vascular obstructive diseases: a pilot study.

The sampling of vascular obstruction diseases remains a challenge in clinical practice. This retrospective study aimed to evaluate the feasibility, accuracy, and safety of intravascular forceps biopsy (IVFB) for the diagnosis of vascular obstructive diseases. From January 2015 to January 2022, of the total of 35 patients who underwent IVFB (21 male, 14 female; mean age 60±11 years; range, 39-81 years), 32 (91.4%) did so during interventional planned revascularization procedures and 3 (8.6%) did so due so due to inaccessible or failed percutaneous access. The outcomes of technical success, biopsy times, patient radiation dose (PRD), complications, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy rate (AR) were analyzed. The technical success of IVFB was 100%. The median number of biopsies taken per biopsy session and PRD were 4.0 (range, 3-6) and 712.6 mGy (range, 383.4-1,450.8), respectively. The sensitivity, specificity, PPV, NPV, and AR of IVFB were 87.5% (21/24), 100% (11/11), 100% (21/21), 78.6% (11/14), and 91.4% (32/35), respectively. There were no complications related to IVFB. IVFB is a technically feasible and safe technique with good diagnostic value. The procedure should be considered in patients who are not suitable for percutaneous access, show indistinct imaging characteristics, or are scheduled to undergo revascularization procedure.

Performance and usefulness evaluation of a software-based scatter correction technique for mammographic images

Although physical grids improve contrast in radiographic images by reducing scattered radiation, various artifacts such as grid shadow, moire, and cutoff result in increased patient doses. To overcome these problems, this study evaluates the applicability and usefulness of a material thickness-based scatter-correction technique for mammography. Specifically, this study aims to compare and evaluate the performance of mammography using the proposed software-based scatter correction framework and a physical grid. The proposed technique enables scatter correction based on pre-calculated parameters of a thickness-based scatter kernel at a water slab phantom and an empirical quantity of scatter components in a mammographic system. In the Monte Carlo simulation and experiment, the proposed framework displayed an intensity profile and full width at half maximum that closely approximated those seen in the physical grid. In addition, by applying the proposed framework to the ACR phantom, it was verified that all structures, including specks, were distinctly distinguished. The results demonstrate that the X-ray scatter-correction method with a software-based framework for mammography is applicable to the field of diagnostic imaging, as this approach yields image quality equivalent to that achieved with physical grids while also enabling a reduction in radiation doses for patients.