Intentionally unilateral prostatic artery embolization: Patient selection, technique and potential benefits.

BACKGROUND: Prostatic artery embolization (PAE) is a promising but also technically demanding interventional radiologic treatment for symptomatic benign prostatic hyperplasia. Many technical challenges in PAE are associated with the complex anatomy of prostatic arteries (PAs) and with the systematic attempts to catheterize the PAs of both pelvic sides. Long procedure times and high radiation doses are often the result of these attempts and are considered significant disadvantages of PAE. The authors hypothesized that, in selected patients, these disadvantages could be mitigated by intentionally embolizing PAs of only one pelvic side. AIM: To describe the authors' approach for intentionally unilateral PAE (IU-PAE) and its potential benefits. METHODS: This was a single-center retrospective study of patients treated with IU-PAE during a period of 2 years. IU-PAE was applied in patients with opacification of more than half of the contralateral prostatic lobe after angiography of the ipsilateral PA (subgroup A), or with markedly asymmetric prostatic enlargement, with the dominant prostatic lobe occupying at least two thirds of the entire gland (subgroup B). All patients treated with IU-PAE also fulfilled at least one of the following criteria: Severe tortuosity or severe atheromatosis of the pelvic arteries, non-visualization, or visualization of a tiny (< 1 mm) contralateral PA on preprocedural computed tomographic angiography. Intraprocedural contrast-enhanced ultrasonography (iCEUS) was applied to monitor prostatic infarction. IU-PAE patients were compared to a control group treated with bilateral PAE. RESULTS: IU-PAE was performed in a total 13 patients (subgroup A, n = 7; subgroup B, n = 6). Dose-area product, fluoroscopy time and operation time in the IU-PAE group (9767.8 µGy∙m2, 30.3 minutes, 64.0 minutes, respectively) were significantly shorter (45.4%, 35.9%, 45.8% respectively, P < 0.01) compared to the control group. Clinical and imaging outcomes did not differ significantly between the IU-PAE group and the control group. In the 2 clinical failures of IU-PAE (both in subgroup A), the extent of prostatic infarction (demonstrated by iCEUS) was significantly smaller compared to the rest of the IU-PAE group. CONCLUSION: In selected patients, IU-PAE is associated with comparable outcomes, but with lower radiation exposure and a shorter procedure compared to bilateral PAE. iCEUS could facilitate patient selection for IU-PAE.

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

Background: 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. Materials and Methods: 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. Results: 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. Conclusion: 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.

Expansion of Typical Values for Paediatric Patients in Ireland and Comparison with Published DRLs - Experiences of a Single Institution.

INTRODUCTION: To reduce the risks involved with ionising radiation exposure, typical values (TVs) and diagnostic reference levels (DRLs) have been established to help keep radiation doses 'as low as reasonably practicable. TVs/DRLs provide standardised radiation dose metrics that can be used for comparative purposes. However, for paediatrics, such values should consider the size of the child instead of their age. This study aimed to establish and compare paediatric TVs for chest, abdomen and pelvis radiography. METHODS: Study methods followed processes for establishing paediatric DRLs as outlined by the Health Information and Quality Authority (HIQA). Kerma-area product (KAP) values, excluding rejected images, were retrospectively acquired from the study institution's Picture Archiving and Communications System (PACS). Paediatric patients were categorised into the following weight-based groupings (5 to <15 kg, 15 to <30 kg, 30 to <50 kg, 50 to 80 kg) and stratified based on the examination that was performed (chest, abdomen, and pelvis), and where it was performed (the different X-ray rooms). Anonymised data were inputted into Microsoft Excel for analysis. Median and 3rd quartile KAP values were reported together with graphical illustrations. RESULTS: Data from 407 X-ray examinations were analysed. For the previously identified weight categories (5 to <15 kg, 15 to <30 kg, 30 to <50 kg, 50 to 80 kg), TVs for the chest were 0.10, 0.19, 0.37 and 0.53 dGy.cm2, respectively. For the abdomen 0.39, 1.04, 3.51 and 4.05 dGy.cm2 and for the pelvis 0.43, 0.87, 3.50 and 7.58 dGy.cm2. Between X-ray rooms TVs varied against the institutional TVs by -60 to 119 % (chest), -50 to 103 % (abdomen) and -14 and 24 %% (pelvis). CONCLUSION: TVs in this study follow established trends with patient weight and examination type and are comparable with published literature. Variations do exist between individual examination rooms and reasons are multifactorial. Given that age and size do not perfectly correlate further work should be undertaken around weight-based TVs/DRLs in the paediatric setting.

Evaluation of the reduction of radiation dose received by pediatric patients in new-generation biplane angiocardiography: Randomized controlled study.

Objective: We aimed to evaluate the safety and efficacy of radiation dose reduction with a new-generation biplane angiocardiography system in patients undergoing transcatheter isolated patent ductus arteriosus (PDA) closure. Materials and methods: Fifty pediatric patients who underwent transcatheter PDA closure were randomly divided into two groups as normal radiation dose and low dose. Patients who required additional procedures other than PDA closure were excluded. PDA closure was performed according to the angiographic measurement of the defect. After the procedure, age, weight, sex, PDA measurements, and radiation measurements such as dose-area product (DAP, Gy.cm2) and air kerma (AK, mGy) were compared between the groups. Results: There was no statistically significant difference between the groups in age, sex, weight, PDA diameter, PDA type, device used, and device diameter (p > 0.05). While there was no statistically significant difference between the groups in terms of cine recording, number of recorded images, and fluoroscopy time (p > 0.05), there was a statistically significant difference between the total DAP, cine and fluoroscopy DAP, total AK, frontal and lateral tube AK, and DAP/kg (mGy.m2/kg) measurements (p < 0.05). Conclusion: Transcatheter PDA closure with a low radiation dose is as effective as that with a normal radiation dose. The radiation dose received by the patient during the procedure was significantly reduced. With the vision provided by this study, it seems possible to work with a low radiation dose in other groups of patients.

PyDAP: Automated dental OPG beam area measurement using python and raspberry Pi camera.

INTRODUCTION: This study investigates if inexpensive computer hardware, open-source computer vision and a phosphor screen from disused CR (computed radiography) Cassette can be used to quantitatively assess beam shape and area. MATERIALS AND METHODS: The phosphor screen was affixed to a Carestream CS 8100 dental OPG system and the camera was mounted above the X-ray tube. Videos were acquired of the green light emissions during the tomographic irradiation. Images of a chessboard pattern, attached to the detector were used to correct for camera angulation and provide image pixel size calibration. K-Means colour clustering was used to define beam area. The effect of light conditions on beam dimension measurement was also investigated. The beam width measurement from optimised methodology was compared with that determined from dose calibrated GAFChromicTM XR-SP2film. RESULTS: Videos in dark conditions provided the most reproducible results. FW20M gained from initial sampling matched that obtained using the GAFChromicTM film within the errors of the measurements,6.41 ± 0.09 mm FW20M from this methodology,compared with FW20M (full width at 20 % of maximum) 6.4 ± 0.1 mm from film. The height and area were 126 ± 0.22 mm and 807 ± 11 mm2 respectively. The chess pattern imaging provided a robust means of perspective correction and pixel calibration. There is potential for this methodology to be employed using any digital camera, provided the camera acquisition settings remain constant, the sensor pixels are square, and the camera position is fixed. CONCLUSION: The potential of this low-cost open-source method of beam area measurement using computer vision is thus proven.

Defining field output factors in small fields based on dose area product measurements: A feasibility study.

BACKGROUND: Dose area product in water (DAPw) in small fields relies on the use of detectors with a sensitive area larger than the irradiation field. This quantity has recently been used to establish primary standards down to 5 mm field size, with an uncertainty smaller than 0.7%. It has the potential to decrease the uncertainty related to field output factors, but is not currently integrated into treatment planning systems. PURPOSE: This study aimed to explore the feasibility of converting DAPw into a point dose in small fields by determining the volume averaging correction factor. By determining the field output factors, a comparison between the so-called "DAPw to point dose" approach and the IAEA TRS483 methodology was performed. METHOD: Diodes, microdiamonds, and a micro ionization chamber were used to measure field output factors following the IAEA TRS483 methodology on two similar linacs equipped with circular cones down to 6 mm diameter. For the "DAPw to point dose" approach, measurements were performed with a dedicated and built-in-house 3 cm diameter plane-parallel ionization chamber calibrated in terms of DAPw in the French Primary Dosimetry Standards Laboratory LNE-LNHB. Beam profile measurements were performed to generate volume averaging correction factors enabling the conversion of an integral DAPw measurement into a point dose and the determination of the field output factors. Both sets of field output factors were compared. RESULTS: According to the IAEA TRS483 methodology, field output factors were within ±3% for all detectors on both linacs. Large variations were observed for the volume averaging correction factors with a maximum spread between the detectors of 26% for the smallest field size. Consequently, deviations of up to 15% between the "IAEA TRS483" and the "DAPw to point dose" methodologies were found for the field output factor of the smallest field size. This was attributed to the difficulty in accurately determining beam profiles in small fields. CONCLUSION: Although primary standards associated with small uncertainties can be established in terms of DAPw in a primary laboratory, the "DAPw to point dose" methodology requires volume averaging correction to derive a field output factor from DAPw measurements. None of the point detectors studied provided satisfactory results, and additional work using other detectors, such as film, is still required to allow the transfer of a DAP primary standard to users in terms of absorbed point dose.

Reject Analysis in Digital Radiography and Computed Tomography: A Belgian Imaging Department Case Study.

Objective: Reject analysis is usually performed in digital radiography (DR) for quality assurance. Data for computed tomography (CT) rejects remains sparse. The aim of this study is to help provide a straightforward benchmark for reject analysis of both DR and CT. Materials and methods: This retrospective observational study included 107,277 DR and 20,659 CT during 18 months in a tertiary care center. Rejected acquisitions were retrieved by Dose Archiving and Communication System (DACS). The DR and CT reject analysis included reject rates, reasons for rejection and supplementary radiation dose associated with these rejects. Results: 8,904 rejected DR and 514 rejected CT were retrieved. The DR reject rate was 8.3% whereas the CT reject rate was 2.5%. The cumulative effective dose (ED) of DR rejects was 377.3 mSv while the cumulative ED of CT rejects was 1267.4 mSv. The major reason for rejects was positioning for both DR (61%) and CT (44%). Conclusion: This study helps constitute a simple reproducible method to analyze both DR and CT rejects simultaneously. Although CT rejects are less often monitored than DR rejects, the radiation dose associated with CT rejects is much higher, which emphasizes the need to systematically monitor both DR and CT rejects. Investigating the reasons and the most frequently rejected examinations gives an opportunity for improvement of imaging techniques in cooperation with technologists.

Angiographic Imaging of Prostatic Artery Origin in a Greek Population and Correlation With Technical and Clinical Aspects of Prostatic Artery Embolization.

Background This study aimed, first, to angiographically investigate and analyze prostatic artery (PA) origin in a Greek male population with benign prostatic hyperplasia (BPH) treated with prostatic artery embolization (PAE) and, second, to correlate prostatic arterial anatomy with technical and clinical aspects of PAE. Methodology This was a retrospective study of BPH patients who underwent PAE in a single tertiary center in Greece from June 2019 to July 2022. For the first part of the study, PA was imaged with computed tomography angiography (CTA) before PAE and with digital subtraction angiography (DSA) during PAE in all patients. A widely accepted system for the classification of PA origin was applied. Type I, a common origin of PA and superior vesical artery (SVA) from the anterior division of internal iliac artery (IIA). Type II, PA originating from the anterior division of IIA, separate from, and inferior to SVA. Type III, the origin of PA from the obturator artery. Type IV, the origin of PA from the internal pudendal artery. Type V, rarer origins of PA. For the second part of the study, a subgroup of patients from the first part (treated with the same PAE protocol and free of vascular pathology that could have interfered with the technical success of PAE) was selected. In this subgroup, differences in PA origin were correlated with technical aspects (feasibility of catheterization of PA, fluoroscopy time (FT), dose area product (DAP)) and clinical outcomes of PAE. Results After the exclusion of four patients, 159 patients were included in the first part of the study. From a total of 355 PAs, 110 (31%) were compatible with type I, 58 (16.3%) type II, 45 (12.7%) type III, 110 (31%) type IV, and 32 (9%) type V. PA origin from an accessory internal pudendal artery was the most common among the rare origins of type V. Regarding the second part of the study (a subgroup of 101 patients selected to facilitate comparisons between the different types of PA origin), type I was associated with significantly more incidences of failed or difficult catheterization of the PA compared to all other types combined (27/64 vs. 18/138, p < 0.001). Types III, IV, and V showed a relatively low degree of technical difficulty. Patients with type I PA origin of at least one pelvic side (subgroup (I), n = 48) had significantly longer FT and DAP compared to the rest (subgroup (O), n = 53). Clinical success rates of PAE were slightly lower for the subgroup (I), although the difference was not statistically significant (75.8% vs. 83.8% at 18 months post-PAE, p = 0.137). No major complications were observed. Conclusions This is the first study of PA origin in Greece. It was demonstrated that types I and IV of PA origin were the most common and had the same prevalence. Type I showed significantly higher technical difficulty compared to the others, but had no significant impact on the clinical outcomes of PAE.

Simulation study on the conversion between CT and CBCT dose quantities via the effective dose.

In recent years, cone-beam computed tomography (CBCT) has been used in many imaging tasks traditionally performed by computed tomography (CT). This has created challenges for dosimetry, as the dose quantities in CBCT and CT, i.e. the dose-area product (DAP) and dose-length product (DLP), are not mutually convertible. Convertibility would be desirable to compare doses in similar clinical studies performed using CT or CBCT and ultimately for the application of diagnostic reference levels (DRLs). In this work, the conversion of the DAP into the DLP and vice versa via the effective doseEis investigated with the aim of finding common diagnostic reference levels. The dose calculation was performed using Monte Carlo simulations for scan regions with imaging tasks, which can be carried out either with CT or CBCT scanners. Four regions in the head and four in the trunk were chosen. The calculations resulted in conversion coefficientsk=DAPDLPof 30(4) cm for the cranium, 22(4) cm for the facial bones, 24(2) cm for the paranasal sinuses, 18(2) cm for the cervical spine, 78(12) cm for the thorax, 85(13) cm for the upper abdomen, 57(6) cm for the lumbar spine and 70(12) cm for the pelvis.

Radiation Exposure in Interventional Stroke Treatment : Analysis of the German Neurointerventional Database (DeGIR/DGNR) from 2019 to 2021.

PURPOSE: To evaluate patient-related radiation exposure in interventional stroke treatment by analyzing data from the German Society for Interventional Radiology and Minimally Invasive Therapy (DeGIR) and the German Society of Neuroradiology (DGNR) quality registry from 2019-2021. METHODS: The DeGIR/DGNR registry is the largest database of radiological interventions in Germany. Since the introduction of the registry in 2012, the participating hospitals have entered clinical and dose-related data on the procedures performed. To evaluate the current diagnostic reference level (DRL) for mechanical thrombectomy (MT) in stroke patients, we analyzed interventional data from 2019 to 2021 with respect to the reported dose area product (DAP) and factors that might contribute to the radiation dose, such as the localization of the occlusion, technical success using the modified treatment in cerebral ischemia (mTICI) score, number of passages, technical approach, additional intracranial/extracranial stenting, and case volume per center. RESULTS: A total of 41,538 performed MTs from 180 participating hospitals were analyzed. The median DAP for MT was 7337.5 cGy∙cm2 and the corresponding interquartile range (IQR) Q25 = 4064 cGy∙cm2 to Q75 = 12,263 cGy∙cm2. In addition, we discovered that the dose was significantly influenced by occlusion location, number of passages, case volume per center, recanalization score, and additional stenting. CONCLUSION: We conducted a retrospective study on radiation exposure during MT in Germany. Based on the results of more than 41,000 procedures, we observed that the DRL of 14,000 cGy·cm2 is currently appropriate but may be lowered over the next years. Furthermore, we identified several factors that contribute to high radiation exposure. This can aid in detecting the cause of an exceeded DRL and optimize the treatment workflow.

Radiation dose during interventional cardiology procedures: portable C-arm vs. a new generation fluoroscopy system.

INTRODUCTION: Occupational exposure to ionizing radiation poses health risks for veterinary interventionalists. There are limited veterinary studies evaluating radiation dose in the cardiac catheterization laboratory. The purpose of this study was to report direct radiation dose exposure to patients during common interventional cardiology procedures and compare these doses between two fluoroscopy units. ANIMALS: One hundred and fifty-four client-owned dogs. MATERIALS AND METHODS: Patient dose during procedures using a portable C-arm were retrospectively analyzed and compared to those performed in a contemporary interventional suite. Fluoroscopy equipment, procedure type, operator, patient weight, fluoroscopy time, dose area product, and air kerma were recorded and statistically modeled using univariable and multivariable linear regression to evaluate the effect of each factor. RESULTS: Patient dose population (154 dogs), comprised 61 patent ductus arteriosus occlusions, 60 balloon pulmonary valvuloplasties, and 33 pacemaker implantations. Patient dose was significantly lower in the group utilizing a newer generation fluoroscopy unit vs. the group utilizing an older portable C-arm, positively correlated with patient weight, and highest during balloon pulmonary valvuloplasties compared to patent ductus arteriosus occlusions or pacemaker implantations (all P<0.010). DISCUSSION: Newer fluoroscopy systems can be equipped with technologies that improve image quality while reducing patient dose and radiation exposure to interventional personnel. CONCLUSIONS: We documented a significant reduction in patient radiation dose using a newer fluoroscopy system as compared to an older portable C-arm for interventional cardiology procedures in animals. Improved knowledge of patient radiation dose factors may promote better radiation safety protocols in veterinary interventional cardiology.

The Impact of Data Management on the Achievable Dose and Efficiency of Mammography and Radiography During the COVID-19 Era: A Facility-Based Cohort Study.

Purpose: To evaluate the impact of using computational data management resources and analytical software on radiation doses in mammography and radiography during the COVID-19 pandemic, develop departmental diagnostic reference levels (DRLs), and describe achievable doses (ADs) for mammography and radiography based on measured dose parameters. Patients and Methods: This ambispective cohort study enrolled 795 and 12,115 patients who underwent mammography and radiography, respectively, at the King Fahd Hospital of the University, Al-Khobar City, Saudi Arabia between May 25 and November 4, 2021. Demographic data were acquired from patients' electronic medical charts. Data on mammographic and radiographic dose determinants were acquired from the data management software. Based on the time when the data management software was operational in the institute, the study was divided into the pre-implementation and post-implementation phases. Continuous and categorical variables were compared between the two phases using an unpaired t-test and the chi-square test. Results: The median accumulated average glandular dose (AGD; a mammographic dose determinant) in the post-implementation phase was three-fold higher than that in the pre-implementation phase. The average mammographic exposure time in the post-implementation phase was 16.3 ms shorter than that in the pre-implementation phase. Furthermore, the median values of the dose area product ([DAP], a radiographic dose determinant) were 9.72 and 19.4 cGycm2 in the pre-implementation and post-implementation phases, respectively. Conclusion: Although the data management software used in this study helped reduce the radiation exposure time by 16.3 ms in mammography, its impact on the mean accumulated AGD was unfavorable. Similarly, radiographic exposure indices, including DAP, tube voltage, tube current, and exposure time, were not significantly different after the data management software was implemented. Close monitoring of patient radiation doses in mammography and radiography, and dose reduction will become possible if imaging facilities use DRLs and ADs via automated systems.

Use of dose-area product to assess plan quality in robotic radiosurgery.

PURPOSE: In robotic stereotactic radiosurgery (SRS), optimal selection of collimators from a set of fixed cones must be determined manually by trial and error. A unique and uniformly scaled metric to characterize plan quality could help identify Pareto-efficient treatment plans. METHODS: The concept of dose-area product (DAP) was used to define a measure (DAPratio) of the targeting efficiency of a set of beams by relating the integral DAP of the beams to the mean dose achieved in the target volume. In a retrospective study of five clinical cases of brain metastases with representative target volumes (range: 0.5-5.68 ml) and 121 treatment plans with all possible collimator choices, the DAPratio was determined along with other plan metrics (conformity index CI, gradient index R50%, treatment time, total number of monitor units TotalMU, radiotoxicity index f12, and energy efficiency index η50%), and the respective Spearman's rank correlation coefficients were calculated. The ability of DAPratio to determine Pareto efficiency for collimator selection at DAPratio < 1 and DAPratio < 0.9 was tested using scatter plots. RESULTS: The DAPratio for all plans was on average 0.95 ±â€¯0.13 (range: 0.61-1.31). Only the variance of the DAPratio was strongly dependent on the number of collimators. For each target, there was a strong or very strong correlation of DAPratio with all other metrics of plan quality. Only for R50% and η50% was there a moderate correlation with DAPratio for the plans of all targets combined, as R50% and η50% strongly depended on target size. Optimal treatment plans with CI, R50%, f12, and η50% close to 1 were clearly associated with DAPratio < 1, and plans with DAPratio < 0.9 were even superior, but at the cost of longer treatment times and higher total monitor units. CONCLUSIONS: The newly defined DAPratio has been demonstrated to be a metric that characterizes the target efficiency of a set of beams in robotic SRS in one single and uniformly scaled number. A DAPratio < 1 indicates Pareto efficiency. The trade-off between plan quality on the one hand and short treatment time or low total monitor units on the other hand is also represented by DAPratio.

Can intraoperative radiation dose in percutaneous posterior thoracolumbar internal fixation be reduced by impedancemetry-guided pedicle sighting? A prospective randomized study.

INTRODUCTION: Percutaneous spine surgery is on the rise; the main drawback is iterative irradiation of the care team in theater. The aim of the present study was to compare intraoperative radiation dose in percutaneous posterior thoracolumbar internal fixation (PPTLIF) using impedancemetry-guided pedicle sighting by the PediGuard device (SpineGuard®) versus gold-standard free-hand sighting. MATERIAL AND METHODS: A single-center, single-surgeon continuous prospective randomized study was conducted from September 2017 to April 2018. Dose-area product (DAP, in cGy.cm2) was recorded at the end of pedicle sighting and end of surgery in the free-hand control group and the impedancemetry group. Pedicle screw position was studied on postoperative CT scan. RESULTS: Sixteen patients were included in either group after 2 had been excluded. The groups were comparable for age, gender, body-mass index (BMI), indication and number of instrumented levels. Mean DPA at end of sighting and end of procedure was respectively 147.4 cGy.cm2 and 230.9 cGy.cm2 in the control group and 171.1 cGy.cm2 and 280.7 cGy.cm2 in the PediGuard group (p> 0.05). Screw positioning on CT was comparable in the 2 groups. CONCLUSION: In the present study, the PediGuard device did not reduce intraoperative radiation dose. The correlation between radiation dose and BMI was confirmed. LEVEL OF EVIDENCE: II; prospective randomized study.

The impact of body mass index on patient radiation dose in general radiography.

The aim of the present study was to determine the influence of the body mass index (BMI) on the dose area product (DAP) and effective dose (ED) in overweight and obese patients. We also wanted to determine the typical dose values as well as suggest adjustments to clinical practice for overweight and obese patients. In this study we considered 597 patients referred for imaging of the chest in posteroanterior and lateral projection, the lumbar spine in anteroposterior (AP) and lateral projection, the pelvis, the knee in AP and lateral projection, and the shoulder in AP projection. For each examination, the image field size, tube voltage, mAs product, source-to-image receptor distance and values of DAP were collected. Based on their BMI, the patients were divided into three groups (normal weight, overweight and obese). At the end, PCXMC 2.0 software was used to calculate the ED. The study showed a statistically significant DAP and ED increase in overweight and obese patients by 28.9% up to 275.4% in the case of DAP and an increase in ED from 11.0% to 241.9% in all mentioned examinations except knee and shoulder imaging. Typical DAP values ranged from 2.2 to 54.8µGym2for normal-weight patients, from 2.2 to 87.6µGym2for overweight patients, and from 2.2 to 172.5µGym2for obese patients. Spearman's correlation coefficient revealed very weak to very strong correlations when comparing BMI and DAP, as well as when comparing BMI and ED. A strong and very strong correlation was found in the case of examinations of the torso (except for the comparison of BMI and ED in the case of lateral lumbar spine projection).

A Retrospective, Single-Center Study of Technical-Procedural Factors Affecting Radiation Dose During Prostatic Artery Embolization.

Introduction This study aims to evaluate the effect of technical-procedural factors on radiation dose during prostatic artery embolization (PAE). Methods This was a single-center, retrospective study of 59 patients with benign prostatic hyperplasia (BPH) who underwent prostatic artery embolization from March 2020 to September 2021. Computed tomography angiography (CTA) was performed for vascular planning prior to PAE in all patients. The effect of the following techniques on the dose area product (DAP) of PAE was evaluated: application of low-dose protocol (LDP) for digital subtraction angiography (DSA), reduction of oblique projections by performing PAE of at least one pelvic side utilizing anteroposterior projections only (AP-PAE), utilization of "roadmap" technique instead of DSA for the delineation of pelvic arterial anatomy (RDMP-PAE), and cone-beam CT (CBCT). The impact of the patient's body mass index (BMI) on DAP was also calculated. The effective dose (ED) of PAE and pre-PAE CTA was calculated from DAP and from dose length products, respectively, using appropriate conversion factors. Results For the entire study population (n = 59), the mean DAP of PAE was 16,424.7 ± 8,019 µGy‧m2. On simple regression analysis, LDP, AP-PAE, and RDMP-PAE significantly contributed to DAP reduction during PAE (30% (p = 0.004), 26.7% (p = 0.013), and 31.2% (p = 0.004), respectively). On multiple regression, LDP and AP-PAE maintained their significant effect (p = 0.002 and p = 0.006, respectively). CBCT was associated with a not statistically significant increase in DAP (10.1%) (p = 0.555). The ED of CTA represented 21.2% ± 10.6% of the ED of PAE. Conclusion Of the four studied factors, LDP, AP-PAE, and RDMP-PAE proved to be relatively simple and widely available techniques that could limit radiation exposure of both the operators and the patients during PAE. The contribution of planning CTA to the overall radiation exposure of patients undergoing PAE appears to be not negligible.

Anthropometric parameters and radiation doses during percutaneous coronary procedures.

PURPOSE: Body size is a major determinant of patient's dose during percutaneous coronary interventions (PCI). Body mass index, body surface area (BSA), lean body mass and weight are commonly used estimates for body size. We aim to identify which of these measures and which procedural/clinical characteristics can better predict received dose. METHODS: Dose area product (DAP, Gycm2), fluoroscopy DAP rate (Gycm2/min), fluoroscopy DAP (Gycm2), cine-angiography DAP (Gycm2), Air Kerma (mGy) were selected as indices of patient radiation dose. Different clinical/procedural variables were analysed in multiple linear regression models with previously mentioned patient radiation dose parameters as end points. The best model for each of them was identified. RESULTS: Overall 6623 PCI were analysed, median fluoroscopy DAP rate was 35 [IQR 2.7,4.4] Gycm2, median total DAP was 62.7 [IQR 38.1,107] Gycm2. Among all anthropometric variables, BSA showed the best correlation with all radiation dose parameters considered. Every 1 m2 increment in BSA added 4.861 Gycm2/min (95% CI [4.656, 5.067]) to fluoroscopy DAP rate and 164 Gycm2 (95% CI [145.3, 182.8]) to total DAP. Height and female sex were significantly associated to a reduction in fluoroscopy DAP rate and total DAP. Coronary angioplasty, diabetes, basal creatinine and the number of treated vessels were associated to higher values. CONCLUSIONS: Main determinants of patient radiation dose are: BSA, female sex, height and number of treated vessels. In an era of increasing PCI complexity and obesity prevalence, these results can help clinicians tailoring X-ray administration to patient's size.

Transseptal versus retrograde approach for ablation of left-sided accessory pathways: impact on radiation exposure.

Management of left-sided accessory pathways (APs) is based on catheter ablation through an antegrade or retrograde approach. Both are safe and effective but are associated with exposure to x-rays; however, recipients of ablation are generally young. We sought to evaluate the impact of the approach chosen on dose-area product (DAP). A total of 95 patients who underwent radiofrequency ablation of a left-sided AP between January 2011 and January 2020 were included. The primary endpoint was the radiation dose received by the patient. Secondary endpoints were procedural success and complication and recurrence rates. The mean age of the study population was 34.3 ± 16.6 years. The antegrade transseptal approach was used in 63.5% of cases. By multivariate analysis, the antegrade transseptal approach was associated with a 53% reduction in DAP (p< 0.001). The radiation dose received was also significantly associated with body mass index and total fluoroscopy time (p< 0.001). There was no significant difference in other secondary endpoints between approaches. The use of an antegrade transseptal approach is associated with a significant reduction in DAP compared with the retrograde approach, and procedural success and complication and recurrence rates are similar.

Clinical Evaluation of Fiducial Marker Pre-Planning for Virtual Bronchoscopic Navigation Implantation in Lung Tumour Patients Treated With CyberKnife.

Purpose: For the treatment of invisible lung tumours with CyberKnife (CK), fiducial markers (FMs) were implanted as an internal surrogate under virtual bronchoscopic navigation (VBN). This research aims to study the benefits of introducing an additional procedure in assigning the optimal FM positions using a pre-procedure planning system and performing virtual simulation before implantation. The objectives were 1) to reduce the duration of the FM implantation procedure, 2) to reduce the radiation exposure in dose area product (DAP) (dGy*cm2) to patients, and 3) to increase the number of FMs implanted around the tumour. Methods and Materials: This study is retrospective, single-centre, and observational in nature. A total of 32 patients were divided into two groups. In Group 1, 18 patients underwent conventional VBN FM implantation. In Group 2, 14 patients underwent additional pre-procedure planning and simulation. The steps of pre-procedure planning include 1) importing CT images into the treatment planning system (Eclipse, Varian Medical Systems, Inc.) and delineating five to six FMs in their ideal virtual positions and 2) copying the FM configuration into VBN planning software (LungPoint Bronchus Medical, Inc.) for verification and simulation. Finally, the verified FMs were deployed through VBN with the guidance of the LungPoint planning software. Results: A total of 162 FMs were implanted among 35 lesions in 32 patients aged from 37 to 92 (median = 66; 16 men and 16 women). Results showed that 1) the average FM insertion time was shortened from 41 min (SD = 2.05) to 23 min (SD = 1.25), p = 0.00; 2) the average absorbed dose of patients in DAP was decreased from 67.4 cGy*cm2 (SD = 14.48) to 25.3 cGy*cm2 (SD = 3.82), p = 0.01 (1-tailed); and 3) the average number of FMs implanted around the tumour was increased from 4.7 (SD = 0.84) to 5.6 (SD = 0.76), p = 0.00 (1-tailed). Conclusion: Pre-procedure planning reduces the FM implantation duration from 41.1 to 22.9 min, reduces the radiation exposure in DAP from 67.4 to 25.3 dGy*cm2, and increases the number of FMs inserted around the tumour from 4.7 to 5.6.

Combining Shape-Sensing Robotic Bronchoscopy With Mobile Three-Dimensional Imaging to Verify Tool-in-Lesion and Overcome Divergence: A Pilot Study.

Objective: To determine whether CT-to-body divergence can be overcome to improve the diagnostic yield of peripheral pulmonary nodules with the combination of shape-sensing robotic-assisted bronchoscopy (SSRAB) and portable 3-dimensional (3D) imaging. Patients and Methods: A single-center, prospective, pilot study was conducted from February 9, 2021, to August 4, 2021, to evaluate the combined use of SSRAB and portable 3D imaging to visualize tool-in-lesion as a correlate to diagnostic yield. Results: Thirty lesions were subjected to biopsy in 17 men (56.7%) and 13 women (43.3%). The median lesion size was 17.5 mm (range, 10-30 mm), with the median airway generation of 7 and the median distance from pleura of 14.9 mm. Most lesions were in the upper lobes (18, 60.0%). Tool-in-lesion was visualized at the time of the procedure in 29 lesions (96.7%). On the basis of histopathologic review, 22 (73.3%) nodules were malignant and 6 (20.0%) were benign. Two (6.7%) specimens were suggestive of inflammation, and the patients elected observation. The mean number of spins was 2.5 (±1.6) with a mean fluoroscopy time of 8.7 min and a mean dose area product of 50.3 Gy cm2 (±32.0 Gy cm2). There were no episodes of bleeding or pneumothorax. The diagnostic yield was 93.3%. Conclusion: This pilot study shows that the combination of mobile 3D imaging and SSRAB of pulmonary nodules appears to be safe and feasible. In conjunction with appropriate anesthetic pathways, nodule motion and divergence can be overcome in most patients. Trial Registration: https://clinicaltrials.gov Identifier NCT04740047.