Patient Radiation Exposure Research Articles

Assessment of a New CT Detector and Filtration Technology: Part 1 - X-ray Beam Characterization and Radiation Dosimetry.

This study evaluated beam quality and radiation dosimetry of a CT scanner equipped with a novel detector and filtration technology called PureVision Optics (PVO). PVO features miniaturized electronics, a detector cut with microblade technology, and increased filtration in order to increase x-ray detection and reduce image noise. We assessed the performance of two similar 320-detector CT scanners: one equipped with PVO and one without. Beam quality was measured by determining the half-value layer (HVL) and effective energy (Eeff) for both scanners using all tube voltages (80 kV, 100 kV, 120 kV, 135 kV) and bowtie filters (small, medium, large) available. Energy correction factors were identified for optically stimulated luminescent dosimeters (OSLDS) compared to a calibrated ionization chamber. Surface and internal doses were measured for an anthropomorphic CT angiography head phantom and a cadaver head scanned with CTDIvol matched as close as possible at the conventional (55.1 mGy) and PVO (55.4 mGy) CT scanners. For all scan settings, the PVO scanner showed significantly higher HVL (range, 4.33-11.02 mm Al) and effective energy (range, 39.4-68.0 keV) values compared to the conventional scanner (HVL, 4.19-8.25 mm Al; effective energy, 38.4-55.2 keV). For equivalent CTDIvol values, the energy-corrected surface skin and lens doses were on average 6.7% lower with the PVO scanner than the conventional scanner (P < 0.01). PVO technology yielded higher HVL and effective energies and, for the same CTDIvol, resulted in lower surface organ doses, indicating a potential for reduced patient radiation exposure in clinical settings.

Effect and safety of percutaneous endoscopic interlaminar discectomy for L5-S1 disc herniation: direct inferior endplate approach versus indirect approach.

To explore the efficacy and safety of the direct inferior endplate approach in percutaneous endoscopic interlaminar discectomy (PEID) for the treatment of L5-S1 disc herniation. This was a retrospective analysis of 116 patients with L5-S1 disc herniation treated with PEID; 74 patients underwent surgery via the direct inferior endplate approach (group A), and 42 patients underwent surgery via the indirect approach (group B). The number of intraoperative fluoroscopy exposures, establishment channel time, operation time, postoperative visual analogue scale (VAS) score, and Oswestry Disability Index (ODI) were compared between the 2 groups. Compared with those in Group B, the channel establishment time, number of fluoroscopy exposures, and operation time in Group A were significantly lower (P < 0.05). There was no significant difference in the VAS score or ODI between the two groups (P > 0.05). Compared with the indirect approach, the direct inferior endplate approach can allow the exposed target to be reached more quickly, shorten the operation time, and reduce the degree of radiation exposure of doctors and patients, resulting in a high safety profile.

Comparison of patient radiation exposure in coronary angiography via the trans-radial versus trans-femoral approach.

Cardiac catheterization via the trans-radial approach (TRA) has shown several advantages over the trans-femoral approach (TFA) but with a concern of higher radiation exposure. Considering the growing experience with TRA, this study compares patient's radiation during coronary angiography using TRA versus TFA. This study included consecutive patients undergoing coronary angiogram over a year at tertiary hospital performed by experienced operators through radial or femoral access. Parameters compared between the two routes included fluoroscopy time (FT), cineangiography time (CT), cini-sequences (CS), and patient radiation exposure quantified by Air Kerma (AK) and Dose Area Product (DAP). A total of 910 patients were studied, with 461 (50.6%) undergoing coronary angiography (CAG) via TFA and 449 (49.4%) via TRA. The mean age was similar between the femoral (54.07) and radial groups (53.7) years (P = 0.33), with slightly lesser proportion of males in the femoral group (74.62% vs 79.73%; P = 0.06). The mean (SD) DAP and AK were 15.71 (7.05) Gy·cm2 and 258.3 (99.9) mGy for the femoral group, compared to 20.76 (9.48) Gy·cm2 and 352.2 (151.5) mGy for the radial group (both P < 0.001). The mean (SD) FT, CT, and CS were 1.32 (0.94) minutes, 40.4 (9) seconds, and 5.93 (1.22) for the femoral group, compared to 2.19 (1.67) minutes, 44 (10) seconds, and 6.17 (1.26) for the radial group (all P < 0.01). Coronary angiography via TRA is associated with increased patient's radiation. Future studies should investigate strategies to reduce radiation exposure in trans-radial procedures.

Evolving operator practices reduced patient radiation dose in Interventional Cardiology: Trends in a single center.

This retrospective study addresses the role of operator and fluoroscopy equipment in reducing patient radiation exposure in the Cath lab. Data from 99,400 procedures performed in our institution between 2007 and 2019 were reviewed. Dosimetric parameters included reference point air kerma (Ka,r), Kerma Area Product (PKA), fluoroscopic time, and contrast volume. Results are characterized by their 50th and 99th percentiles. Data from a subset of fluoroscopes that were in continuous use and a subset of operators who used the same "continuous" fluoroscope in every year of the study were also analyzed. For all procedures, median Ka,r declined by 63%, from 1.5 to 0.5 Gy; 99th percentiles declined by 44%, from 8.6 to 4.8 Gy. For the three "continuous fluoroscopes" median Ka,r declined by 60% from 1.6 to 0.6 Gy; 99th percentile by 52% from 9.1 to 4.4 Gy. The all-procedure median contrast volume declined by 53%, from 150 to 70 ml; 99th percentile by 42% from 600 to 350 ml. The all-procedure median fluoroscopy time declined by 2%; the 99th percentile increased by 32%. In the continuous subset, median fluoroscopy time declined by 20%; 99th percentile increased by 5%. For the operator's subset, the median Ka,r declined by 43% (p=0.0362); the 99th percentile decreased by 22% (p=0.0481). Substantial radiation dose procedures decreased from 7% to 0.8% of the procedure volume. There was a significant reduction in patient radiation (Ka,r and PKA) and contrast volume during the study period driven by systematic and operator practice changes.

Evaluation of three diagnostic algorithms to reduce normal scan rates, radiation exposure and costs in patients with suspected chronic coronary syndrome referred for 82Rb-Positron Emission Tomography (82Rb-PET)

BackgroundThe majority of functional ischemia tests in patients with suspected chronic coronary syndromes (CCS) yield normal results. Implementing gatekeepers for patient preselection, such as pretest probability (PTP) and/or coronary artery...

Radiation exposure in neurosurgical intensive care unit patients: Balancing diagnostic benefits and long-term risks

Radiation exposure in neurosurgical intensive care unit patients: Balancing diagnostic benefits and long-term risks

Comparison and Optimization of Machine Learning Regression Models for Predicting Electromagnetic Radiation Exposure in Patients Undergoing Coronary Angiography

Comparison and Optimization of Machine Learning Regression Models for Predicting Electromagnetic Radiation Exposure in Patients Undergoing Coronary Angiography

Interior design model proposal for nuclear medicine imaging rooms

Innovative design approaches to prevent radiation contamination in nuclear medicine departments have been examined. Nuclear medicine departments are high-risk areas for radiation contamination due to the use of radioactive materials. The strategies employed to prevent the spread of radiation in the design of these departments have been detailed. Theranostic approaches, which utilize radiopharmaceuticals in both diagnostic and therapeutic processes, have been emphasized, and the measures aimed at minimizing radiation exposure for patients, personnel, and the public have been evaluated. The proposed design model suggests a spatial arrangement that separates the movement pathways of patients, personnel, and caregivers to minimize the risk of radiation contamination. In conclusion, it has been demonstrated that the integration of appropriate architectural design principles can significantly reduce the risk of radiation exposure in nuclear medicine departments, thereby ensuring a safe environment for both patients and healthcare professionals

Comparison of patient radiation exposure and procedure time between CT-fluoroscopy and spiral CT for lumbar epidural steroid injections.

To compare patient radiation exposure and procedure time for lumbar epidural steroid injections (ESIs) performed under CT-fluoroscopy (CTF) vs spiral CT-guidance. A retrospective cohort study of 767 consecutive lumbar ESIs performed between 2015-2023 using CTF vs spiral CT-guidance was conducted. Patient characteristics (age, sex, weight), procedural characteristics (injection level, type of ESI, trainee participation), and outcomes (patient radiation exposure, procedure time, pain relief, complications) were compared. Student's t and chi-squared tests were performed for statistical analysis. There were 240 CTF and 527 spiral CT-guided lumbar ESIs. There were no significant differences in patient demographics between groups. Radiation exposure for the CTF group was 37.2 ± 50.5mGy cm, compared to 251.1 ± 178.6mGy cm in the spiral CT group (p < 0.001). Procedure times were shorter in the CTF group (20.1 ± 6.1 vs 29.6 ± 12.9min, p < 0.001). There was no significant difference in immediate post-procedure pain reduction in CTF vs spiral CT groups (p = 0.12). There were no intrathecal puncture complications in the CTF group and four in the spiral CT group. Subgroup analysis of attending-only and trainee-performed lumbar ESIs comparing CTF vs spiral-CT groups showed similar results as the primary analysis, with significant reductions in patient radiation (attending: 31.6 ± 40.7 vs 144.4 ± 97.4mGy cm; trainee: 40.7 ± 55.5 vs 264.5 ± 182.0mGy cm; both p < 0.001) and procedural time (attending: 18.3 ± 4.2 vs 24.4 ± 7.4min; trainee: 21.2 ± 6.8 vs 30.2 ± 12.4; both p < 0.001). Image-guided lumbar ESIs using CTF were associated with less patient radiation exposure and shorter procedure times without differences in pain relief when compared with spiral CT technique in our practice.

Black Bone MRI vs. CT in temporal bone assessment in craniosynostosis: a radiation-free alternative.

Craniosynostoses are rare congenital craniofacial malformations, variably affected by hearing loss, often requiring repeated CT examinations to assess skull or temporal bone (TB) abnormalities. In order to avoid radiation exposure in these young patients, efforts are made to assess the skull abnormalities on MR bone imaging sequences, such as Black Bone (BB). Our aim is to compare BB, a radiation-free imaging technique, with CT for the assessment of the TB. 48 patients who underwent both BB and CT (2016-2021) in Sophia Children's Hospital, Erasmus MC, Rotterdam, were retrospectively investigated. BB and CT (the diagnostic gold standard for imaging the temporal bone) were evaluated blindly and independently by 3 observers; visibility and abnormalities of TB structures and cranial nerves were scored; abnormal findings were confirmed by a senior pediatric neuroradiologist. The statistical analysis was performed using Gwet's AC1 agreement and modified versions of the Wilcoxon signed-rank test and sign test with a Bonferroni-Holm correction (p < 0.05). CT was rated higher than BB in structure visibility (global p = 0.0002), but was rated similar to BB when assessing TB anatomy and pathology (global p = 0.58). The visibility ratings showed better interobserver agreement values on CT than BB. In the normal/abnormal ratings, both BB (0.75-1) and CT (0.88-1) showed high interobserver agreement values. Our preliminary results suggest that BB is a promising tool for screening TB pathology in patients with craniosynostosis who require MR imaging.

Intraoperative patient radiation dose from cone-beam computed tomography in thoracic surgery

BackgroundSeveral methods can be used to intraoperatively identify pulmonary lesion using radiation technology. However, little is known about patient radiation exposure during chest surgery. We aimed to measure patients’ radiation exposure from cone-beam computed tomography (CBCT) used in a hybrid operating room.MethodsThis retrospective study included patients who underwent surgical treatment in a hybrid operating room between April 2019 and December 2023 at the Teikyo University Hospital. All data was obtained prospectively, but the study was approved by the IRB as a retrospective study because of repeated extensions of study period in order to collect more cases. Skin radiation exposure was measured using five wearable dosimeters per patient. The measurements were compared to cumulative Air Kerma. Furthermore, the radiation exposure dose on the surgical side, which cannot be measured, was estimated by computer simulation.ResultsAmong 182 patients who underwent surgery in a hybrid operating room, radiation exposure measurements were conducted on 67 patients. The patients’ mean age was 60.7 years. The average number of CBCT scans was 2.1 (1–5) and the intraoperative identification rate was 100%, with no marking-related complications. Average patient’s skin radiation dose was 3.69 ± 5.48 mGy per dosimeter, and cumulative Air Kerma was 25.4 ± 19.3 mGy. The highest radiation exposure was recorded in the 5th intercostal space whereas the lowest was measured in the supraclavicular or 11th intercostal spaces. Referring to phantom and computer simulation data, the 5th and 8th intercostal spaces were significantly more exposed to radiation at not only measurement side but also the surgical field, particularly when the number of CT scans was four.ConclusionWe found that the patient’s 5th to 8th intercostal space was the most radiation exposed area by intraoperative CBCT imaging because the CBCT movement was restricted by the patient’s arm, anesthesia machine, and operating table during chest surgery. In future, it is strongly required to research for radiation protection in this area. Furthermore, performing no more than three scans intraoperatively may be preferable in order to protect patients from radiation exposure during CBCT guided thoracic surgery.

Impact of X-Ray Protective Drapes on Operator and Patient Radiation Exposure During Cardiac Catheterization.

As cardiac catheterization operators are exposed to radiation exposure throughout their careers, optimal radiation protection is crucial. Our study was designed to assess the effects of supplementary protective measures beyond standard radiation protection attire and barriers, measuring their influence on scatter radiation exposure levels for both the operator and the patient. The objective of this trial is to assess the impact of a lead shield on scatter radiation exposure for both the operator and the patient. We conducted a prospective, randomized clinical trial in which procedures were allocated to incorporate the use of a reusable lead apron designed to shield the lower body of the patient. Both operators and patients were outfitted with real-time procedure-specific dosimeters to monitor exposure. All patients undergoing radial access procedures were entered into a randomization process. The study's dual primary outcomes included the relative operator dose above (RODt) and under (RODu) the protective gear, as well as the scatter patient radiation dose (RPD), which was calculated as the measured radiation exposure (µSv) standardized against the dose area product (DAP). Out of 400 procedures that were randomized, data from 346 procedures was complete for analysis. The use of the pelvic shield resulted in a substantial decrease in the RODt and RODu, with reductions of 25% and 40%, respectively (p < 0.0001). There was also a 38% reduction observed in the scatter RPD. In patients with a high BMI, the effectiveness of the pelvic shield varied. Employing an auxiliary pelvic shield significantly diminishes scatter radiation exposure for both the operator and the patient.

Fluoroscopy Dose and Time During Vertebral Augmentation for Spine Pain Due to Malignant Fractures

Background: Vertebral augmentation (VA) procedures are used to treat painful vertebral fractures caused by malignancies, but there are few data on the radiation exposure for patients and proceduralists during these VA procedures. We retrospectively examined the radiation dose exposure during VA procedures and defined the characteristics of patients who underwent such procedures. Methods: We conducted a retrospective observational cohort study including patients with cancer who experienced axial back pain from compression fractures caused by malignancies. Participants were identified using an electronic medical records database and must have had evidence of stable vertebral compression fractures upon imaging and documentation of a clinical evaluation. We collected data on patient demographics, fluoroscopy time (FT) and dose (FD) during the procedure, the volume of polymethylmethacrylate injected, and reported complications. Results: Overall, 140 patients were included. Their median age was 69, and they were mostly men (n = 79). The most common diagnosis was multiple myeloma (41.4%). Most patients had a single-level compression fracture of the thoracolumbar spine. The mean FT was 233.80 s, with higher FTs for patients with an elevated body mass index and patients younger than 60 years. The average FD was 157.98 mGy, with higher FDs for patients with an elevated BMI and for male patients. Pain relief was not associated with FT or FD. Conclusions: Patients with cancer who underwent VA experienced longer FT and higher FD compared to their non-cancer counterparts in the literature. However, we found multiple confounders for this relationship.

Establishment of recurrent exposures reference levels for repeated computed tomography examinations in adult patients on a nationwide level in Slovakia.

The study aims were: (1) to assess the incidence in 1 year, the cumulative incidences and the period prevalence in 3/5 years of the condition of patients accruing cumulative effective dose (CED) ≥ 100 mSv in health care centres providing CT examinations in Slovakia; and (2) to quantify their variability among different centres, to test the feasibility of establishing recurrent exposure reference levels (RERL) on a nationwide level. The data were tracked during five consecutive years using the CT dose index and dose-length-product along with the patient's ID. ED was calculated using conversion factors. Hospitals were stratified according to the number of beds in clinics (0), small (< 200), medium (201-500), or large (> 500) hospitals. The database included 1,278,928 patients who underwent 2,157,508 CT exams in 5 years. The I100;1 (%), I100;3 (%), I100;5 (%) ranged from 0% to 6.2%, from 0.3% to 23.2% and from 0.3% to 36.9%, respectively. The P100;3 (%), P100;5 (%) ranged from 0.17% to 13.3% and from 0.19% to 17.8%, respectively. No significant differences were found in epidemiological indexes among different hospital sizes. A strong positive correlation was found between the third quartile values of yearly CED and I100;1 (%) (r = 0.84; R2 = 0.70; p < 0.0001). RERL value, set as the 75th percentiles of the distributions of the 3rd quartiles of the yearly CED, amounted to 25.7 mSv. The management of patients with recurrent CT exposures is highly variable among hospitals and unrelated to the size of the institution. Incidence should be reported instead of prevalence. Question Beyond just reporting statistics on recurrent imaging, the question which needs to be addressed is how to use such information to optimise patient protection. Findings In Slovakia the 5-year incidence of patients with CED ≥ 100 mSv average 6% and range from 0.3% to 36.9% among different hospitals. Clinical relevance The incidence of patients with CED ≥ 100 mSv is highly variable among hospitals and unrelated to their size. The heterogeneity in the radiation exposure of recurrent patients prompts the introduction of RERL to aid in the optimisation of patient protection.

X-Ray Utilization Patterns in Pediatric Musculoskeletal Trauma: Assessing Potential Overprescription

Background: Traumatic injuries are among the leading causes of visits to the pediatric emergency department (PED). Objectives: This study aims to evaluate the pediatric approach to musculoskeletal trauma in children to determine whether the routine use of X-rays can be reduced by encouraging the use of ultrasound. Methods: This retrospective observational study included children aged 0 - 18 years admitted to the PED of the Policlinico A. Gemelli with a diagnosis of musculoskeletal trauma from January 2017 to December 2021. Patients were divided into two groups based on the presence of fractures identified through radiological examinations: "Fracture Yes" and "Fracture No." Data on X-rays performed were categorized according to the site of trauma. Results: A total of 5,972 children were enrolled. The most notable findings concern the regions of trauma. Among 1,273 patients who underwent X-rays of the hand region, 617 (48%) showed fractures, and 656 (51%) did not. Of the 744 X-rays performed for the foot region, 235 (31%) revealed fractures, while 509 (68%) were negative for fractures. In the upper limbs region, 1,334 X-rays were performed, with 1,079 (80%) identifying fractures and 255 (20%) showing no fractures. For the lower limbs region, 479 X-rays were conducted, 204 (42%) of which revealed fractures, while 275 (58%) were negative for fractures. All these results demonstrated statistically significant differences (P &lt; 0.05). Conclusions: Despite the limitations of the study's retrospective design and its single-center setting, the findings highlight a high prevalence of X-rays in the hand and upper limb regions, often with positive results. In contrast, radiography of the lower limbs and feet frequently yielded negative findings, suggesting potential overuse. Future research should investigate the clinical utility of musculoskeletal ultrasound as an alternative imaging modality to minimize unnecessary radiation exposure in pediatric patients.

Radiation exposure and protection advice after [177Lu]Lu-DOTA-TATE therapy in China

BackgroundWe conducted a study on radiation exposure in patients with gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) treated with [177Lu]Lu-DOTA-TATE in China for the first time, aiming to provide guidance and reference for radiation protection in this regard. A total of 30 GEP-NENs patients who received [177Lu]Lu-DOTA-TATE therapy were recruited in the study. We measured the external dose rate (EDR) values of each patient during the injection and 0–6 h post-administration period, as well as the radiation dose (RD) values to healthcare nurses and the surrounding environment. We performed a double exponential curve fitting and estimated the RD to the public from patients discharged at different times after [177Lu]Lu-DOTA-TATE therapy.ResultsAmong the 30 patients, 27 patients completed 4 cycles of [177Lu]Lu-DOTA-TATE treatments, the estimated RD to the public indicated that for adult family members, children above 10 years old, children aged 3–10 and coworkers of the patients, patients could begin daily contact at least 24 h, 48 h, 144 h and 192 h after injection to ensure that the total RD values after four treatments not exceed the limit. During the hospitalization of patients receiving [177Lu]Lu-DOTA-TATE, the cumulative dose received by the administering nurses and to the ward environment were both well below the national RD limits.ConclusionsThis study conducted a fitting analysis of the decay pattern of EDR values in GEP-NENs patients undergoing [177Lu]Lu-DOTA-TATE therapy, in order to establish guidelines for patient discharge timing and provide recommendations for radiation protection for the general public after patient discharge.Trial registration A Study Comparing Treatment With Lutetium[177Lu] Oxodotreotide Injection to Octreotide LAR in Patients With GEP-NETs, NCT05459844. https://clinicaltrials.gov/study/NCT05459844?cond=NCT05459844&rank=1. Registered 5 July 2022.

Optimizing Scan Range in Computed Tomography of Kidneys, Ureters, and Bladder: A Retrospective Study on Reducing Overscanning.

Background and Objectives: Computed tomography of the kidneys, ureters, and bladder (CT KUB) is essential for evaluating urinary stones but also exposes patients to significant radiation. The scanning field should be minimized to only the necessary area to limit this radiation exposure. This study aims to assess the extent of CT KUB overscanning in renal colic procedures and identify the appropriate vertebral level for starting CT KUB scans. Materials and Methods: A retrospective analysis of 299 adult patients who underwent CT KUB examinations for kidney stone assessment was performed. To assess overscanning, the number of excess slices above the pole of the highest kidney and under the pubic symphysis was measured on the axial image of each patient. To allow for potential human error, a maximum acceptable level of overscanning was set at 10%. Results: This study found that only 31% of the scans met the target of less than 10% of overscanning superior to the highest kidney and inferior to the pubic symphysis. In comparison, overscanning was present in 69% of the scans, mainly at a superior level, resulting in higher radiation exposure for patients. Conclusions: A significant number of the scans exhibited unnecessary overscanning beyond the highest kidney, prompting us to propose using the upper border of the T10 vertebral body as a potential reference point to establish the upper margin for a CT KUB scan. This study suggests using T10 and the pubic symphysis as reliable landmarks to accurately determine the scan length. Starting CT KUB scans from the T10 vertebral body to the pubic symphysis allows for imaging of the entire urinary tract, minimizing unnecessary overscanning and reducing patient irradiation.

Comparative effectiveness of digital variance and subtraction angiography in lower limb angiography: A Monte Carlo modelling approach

ObjectiveBy modelling patient exposures of interventional procedures, this study compares the reduction of radiation detriment between Digital Variance Angiography (DVA) and Digital Subtraction Angiography (DSA). MethodsThe paper presents a retrospective risk assessment using an in-house developed tool on 107 patient exposures from a clinical trial of DVA used to diagnose peripheral arterial disease (PAD). DICOM exposure parameters were used to initiate the PENELOPE (PENetration and Energy LOss of Positrons and Electrons) Monte Carlo simulation, radiation quality and quantity, and irradiation geometry. The effective dose and the lifetime attributable risk (LAR) for cancer incidence and mortality are calculated based on the International Commission on Radiation Protection’s (ICRP) 103 recommendations and the Committee on the Biological Effects of Ionising Radiations’ latest (BEIR VII) report, respectively. ResultsThe study found that procedures conducted using DVA significantly reduce the radiation exposure of patients, compared to DSA. The collective effective dose for the DVA group was 58% lower than that for the DSA group. Correspondingly, the LAR of different organs showed a substantial decrease for cancer incidence (25–75%) and mortality (51–84%). ConclusionDVA demonstrates a considerable reduction in physical dosimetric quantities and consequently effective dose and cancer risk, suggesting its potential as a safer alternative to DSA in interventional radiology. The use of DVA supports the optimisation of patient radiation protection and aligns with the principles of ALARA (as low as reasonably achievable).

Failure rate of the pulmonary embolism rule-out criteria rule for adults 35 years or younger: Findings from the RIETE Registry.

The use of a computed tomography pulmonary angiogram to diagnose pulmonary embolism (PE) has increased, leading not only to higher PE diagnoses but also to overdiagnosis and unnecessary radiation exposure, even in young patients despite a lower PE incidence. The aim of this study was to assess the failure rate of the pulmonary embolism rule-out criteria 35 (PERC-35) rule developed to reduce unnecessary testing in individuals aged ≤35 years among patients included in the Registro Informatizado de la Enfermedad TromboEmbolica Venosa (RIETE) Registry. This retrospective cohort study used data from the RIETE Registry, an ongoing, international prospective registry of patients with objectively confirmed venous thromboembolism. The primary outcome was the missed PE rate using PERC-35 criteria. Secondary outcomes included the comparison of demographic and clinical characteristics, PE localization, treatment strategies, and outcomes between PERC-negative (PERC-35N) versus PERC-positive (PERC-35P) patients. Of 58,918 adult patients with acute PE, the PERC-35 rule demonstrated a low missed PE rate of 0.35% (n = 204), with an upper 95% confidence interval [CI] of 0.40%. The missed rate was 7.0% (95% CI 6.0%-7.9%) in the 18- to 35-year subgroup. Compared to PERC-35P patients, PERC-35N patients were younger (mean age 28.4 years), with a lower body mass index, and included a higher proportion of pregnant/postpartum women. PERC-35N patients had a significantly lower rate of chronic diseases and presented less frequently with dyspnea or syncope but more often with chest pain. They showed lower rates of positive D-dimer and troponin levels. PERC-35N patients experienced fewer major bleeding episodes, similar recurrence rates of PE/deep vein thrombosis, and no deaths during anticoagulation. The PERC-35 rule demonstrated a low failure rate to exclude PE in patients aged 18-35 years and could reduce imaging and radiation exposure in young patients with a low PE pretest probability if confirmed prospectively.

Radiation exposure and safety in low-dose CT-guided glycerol rhizotomy for trigeminal Neuralgia outside the operating room

BackgroundPercutaneous rhizotomy of the Gasserian ganglion is a well-established intervention for patients suffering from refractory trigeminal pain, not amenable to pharmacological management or microvascular decompression. Traditionally conducted under fluoroscopic guidance using Hartel’s technique, this study investigates a modified approach employing low-dose CT guidance to achieve maximal procedural precision and safety with the emphasis on minimizing radiation exposure.MethodsA retrospective analysis of patients undergoing percutaneous rhizotomy of the Gasserian ganglion at our institution was undertaken. Procedures were divided into fluoroscopy and CT-guided foramen ovale (FO) cannulation cohorts. Radiation doses were assessed, excluding cases with incomplete data. The study included 32 procedures in the fluoroscopy group and 30 in the CT group.ResultsIn the CT-guided group, the median effective dose was 0.21 mSv. The median number of CT scans per procedure was 4.5, and the median procedure time was 15 min. Successful FO cannulation was achieved in all 30 procedures (100%). In the fluoroscopy group, the median effective dose was 0.022 mSv, and the median procedure time was 15 min. Cannulation of FO was successful in 31 of 32 procedures (96.9%).The only complications in the CT-guided group were three minor cheek hematomas. Immediate pain relief in the CT-guided group was reported in 25 of 30 procedures (83.3%), 22 of 30 (73.3%) provided relief at one month, and 10 of 18 (55.6%) procedures resulting in pain relief at one month continued to provide relief after two years.ConclusionLow-dose CT-guided percutaneous rhizotomy conducted in the radiology suite carries negligible radiation exposure for patients and eliminates it for personnel. This method is fast, simple, precise, and carries a very low risk of complications.