Time Trend of the Radiation Exposure Dose in Endoscopic Retrograde Cholangiopancreatography Over an 8-Year Period: A Single-Center Retrospective Study.

INTRODUCTION: The global needs for a reduction in radiation exposure (RE) are increasing. Endoscopic retrograde cholangiopancreatography (ERCP) is a significant fluoroscopic procedure in the gastrointestinal field. However, the actual RE in ERCP and its annual trend are still unclear. Therefore, we examined the yearly trend of RE in ERCP. METHODS: This retrospective, single-center cohort study included consecutive cases of ERCP from September 2012 to June 2019. We measured the air kerma (AK, mGy), dose area product (DAP, Gycm2), and fluoroscopy time (FT, min). We also evaluated the annual trend of the RE before and after the fluoroscopy device update. RESULTS: In total, 2,174 patients receiving ERCP were enrolled. Among these, the mean age was 74.3 years, and 913 patients were women (42.0%). The median/third quartile values of AK (mGy), DAP (Gycm2), and FT (min) were 109/234 mGy, 13.3/25.8 Gycm2, and 18.2/27.7 minutes. The annual AK, DAP, and FT from 2012 to 2019 were 138, 207, 173, 177, 106, 71.0, 45.0, and 33.3 mGy; 23, 21.4, 19, 18.3, 11.9, 9.0, 6.8, and 6.4 Gycm2; and 12.5, 12.1, 9.7, 9.8, 8.2, 10.8, 9.4, and 10.3 minutes, respectively. The corresponding values before and after the update in July 2016 were 177 and 52 mGy (P < 0.0001), 19.2 and 7.6 Gycm2 (P < 0.0001), and 10.2, and 9.9 minutes (P = 0.05), respectively. DISCUSSION: The RE from ERCP tended to decrease every year, especially after fluoroscopy device updates.

Endobronchial Navigation Guided by Cone-Beam CT-Based Augmented Fluoroscopy without a Bronchoscope: Feasibility Study in Phantom and Swine.

PURPOSE: To evaluate the accuracy of cone-beam computed tomography (CT)-based augmented fluoroscopy (AF) image guidance for endobronchial navigation to peripheral lung targets. METHODS: Prototypic endobronchial navigation AF software that superimposed segmented airways, targets, and pathways based on cone-beam CT onto fluoroscopy images was evaluated ex vivo in fixed swine lungs and in vivo in healthy swine (n = 4) without a bronchoscope. Ex vivo and in vivo (n = 3) phase 1 experiments used guide catheters and AF software version 1, whereas in vivo phase 2 (n = 1) experiments also used an endovascular steerable guiding sheath, upgraded AF software version 2, and lung-specific low-radiation-dose protocols. First-pass navigation success was defined as catheter delivery into a targeted airway segment solely using AF, with second-pass success defined as reaching the targeted segment by using updated AF image guidance based on confirmatory cone-beam CT. Secondary outcomes were navigation error, navigation time, radiation exposure, and preliminary safety. RESULTS: First-pass success was 100% (10/10) ex vivo and 19/24 (79%) and 11/15 (73%) for in vivo phases 1 and 2, respectively. Phase 2 second-pass success was 4/4 (100%). Navigation errors were 2.2 ± 1.2 mm ex vivo and 4.9 ± 3.2 mm and 4.0 ± 2.6 mm for in vivo phases 1 and 2, respectively. No major device-related complications were observed in the in vivo experiments. CONCLUSIONS: Endobronchial navigation is feasible and accurate with cone-beam CT-based AF image guidance. AF can guide endobronchial navigation with endovascular catheters and steerable guiding sheaths to peripheral lung targets, potentially overcoming limitations associated with bronchoscopy.

National Diagnostic Reference Levels for Endovascular Aneurysm Repair and Optimisation Strategies.

OBJECTIVE: The International Commission on Radiological Protection (ICRP) has highlighted the large number of medical specialties using fluoroscopy outside imaging departments without programmes of radiation protection (RP) for patients and staff. Vascular surgery is one of these specialties and endovascular aneurysm repair (EVAR) is one of the most challenging procedures requiring RP guidance and optimisation actions. The recent European Directive on Basic Safety Standards requires the use and regular update of diagnostic reference levels (DRL) for interventional procedures. The objective of the study was to know the doses of patients undergoing EVAR with mobile Xray systems and with hybrid rooms (fixed Xray systems), to obtain national DRLs and suggest optimisation actions. METHODS: The Spanish Chapter of Endovascular Surgery launched a national survey that involved hospitals for 10 autonomous communities representing the 77% of the Spanish population (46.7 million inhabitants). Patient dose values from mobile Xray systems were available from nine hospitals (sample of 165 EVAR procedures) and data from hybrid rooms, from seven hospitals, with dosimetric data from 123 procedures. The initial national DRLs have been obtained, as the third quartile of the median values from the different centres involved in the survey. RESULTS: The proposed national DRLs are 278 Gy cm2 for hybrid rooms and 87 Gy cm2 for mobile Xray systems, and for cumulative air kerma (cumulative AK) at the patient entrance reference point, 1403 mGy for hybrid rooms, and 292 mGy for mobile systems. CONCLUSION: An audit of patient doses for EVAR procedures to identify optimised imaging protocol strategies is needed. It is also appropriate to evaluate the diagnostic information required for EVAR procedures. The increase by a factor of 3.2 (for kerma area product) and 4.8 (for cumulative AK) in the DRLs needs to be justified when the procedures are performed in the hybrid rooms rather than with mobile Xray systems.

Head-Mounted Display Use in Surgery: A Systematic Review.

Purpose. We analyzed the literature to determine (1) the surgically relevant applications for which head-mounted display (HMD) use is reported; (2) the types of HMD most commonly reported; and (3) the surgical specialties in which HMD use is reported. Methods. The PubMed, Embase, Cochrane Library, and Web of Science databases were searched through August 27, 2017, for publications describing HMD use during surgically relevant applications. We identified 120 relevant English-language, non-opinion publications for inclusion. HMD types were categorized as "heads-up" (nontransparent HMD display and direct visualization of the real environment), "see-through" (visualization of the HMD display overlaid on the real environment), or "non-see-through" (visualization of only the nontransparent HMD display). Results. HMDs were used for image guidance and augmented reality (70 publications), data display (63 publications), communication (34 publications), and education/training (18 publications). See-through HMDs were described in 55 publications, heads-up HMDs in 41 publications, and non-see-through HMDs in 27 publications. Google Glass, a see-through HMD, was the most frequently used model, reported in 32 publications. The specialties with the highest frequency of published HMD use were urology (20 publications), neurosurgery (17 publications), and unspecified surgical specialty (20 publications). Conclusion. Image guidance and augmented reality were the most commonly reported applications for which HMDs were used. See-through HMDs were the most commonly reported type used in surgically relevant applications. Urology and neurosurgery were the specialties with greatest published HMD use.

[Collected data on freehand technique instrumentation and literature comparison on fluoroscopic and CT-assisted navigation]. / Erhobene Daten zur Instrumentierung in Freihandtechnik und Literaturvergleich zu fluoroskopisch- und CT-gestützter Navigation.

BACKGROUND: A proven and frequently used surgical procedure in patients with idiopathic scoliosis (IS) is posterior transpedicular corrective spondylodesis using the freehand technique. Novel procedures with fluoroscopically and computed tomography (CT)-assisted navigation are presumed to be less risky and more accurate. OBJECTIVE: Is the freehand technique for IS safe with respect to screw-associated complications and intraoperative radiation exposure? MATERIAL AND METHODS: Prospectively collected data (2017-2018) from 39 consecutive patients (average age 18.7 years) with thoracic single curvature IS (61.7°â€¯± 13.9°) from a specialized scoliosis center were evaluated for the following parameters (mean ± standard deviation): total radiation product, fluoroscopy time, fused segments, operative time, blood loss and screw-associated complications. A comparison with data from the literature on intraoperative radiation exposure using navigation procedures was carried out. RESULTS: The total radiation product per patient was 71.7 ± 44.0 cGy*cm2, fluoroscopy time 17.4 ± 8.6 s. (7.8 segments), operative time 183.5 ± 54.2 min and blood loss 379.5 ± 183 ml. There were no screw-associated complications in the entire collective. Correction of the main curvature was 75.7%. Comparison of the data with index data from the literature showed a 1.25-12.5-fold higher radiation exposure for patients with fluoroscopically assisted navigation and 9.25-12.3-fold higher radiation exposure with CT-assisted procedures compared to the present results. CONCLUSION: The results of this study showed that with appropriate experience freehand positioning of pedicle screws is associated with comparable accuracy and less radiation exposure for patients than navigation procedures. With respect to the young age of patients, a radiation-induced long-term risk for malignant diseases should be taken into consideration.

A Dual-layer Detector for Simultaneous Fluoroscopic and Nuclear Imaging.

Purpose To develop and evaluate a dual-layer detector capable of acquiring intrinsically registered real-time fluoroscopic and nuclear images in the interventional radiology suite. Materials and Methods The dual-layer detector consists of an x-ray flat panel detector placed in front of a γ camera with cone beam collimator focused at the x-ray focal spot. This design relies on the x-ray detector absorbing the majority of the x-rays while it is more transparent to the higher energy γ photons. A prototype was built and dynamic phantom images were acquired. In addition, spatial resolution and system sensitivity (evaluated as counts detected within the energy window per second per megabecquerel) were measured with the prototype. Monte Carlo simulations for an improved system with varying flat panel compositions were performed to assess potential spatial resolution and system sensitivity. Results Experiments with the dual-layer detector prototype showed that spatial resolution of the nuclear images was unaffected by the addition of the flat panel (full width at half maximum, 13.6 mm at 15 cm from the collimator surface). However, addition of the flat panel lowered system sensitivity by 45%-60% because of the nonoptimized transmission of the flat panel. Simulations showed that an attenuation of 27%-35% of the γ rays in the flat panel could be achieved by decreasing the crystal thickness and housing attenuation of the flat panel. Conclusion A dual-layer detector was capable of acquiring real-time intrinsically registered hybrid images, which could aid interventional procedures involving radionuclides. Published under a CC BY-NC-ND 4.0 license. Online supplemental material is available for this article.

Radiation dose reduction with frame rate conversion in X-ray fluoroscopic imaging systems with flat panel detector: basic study and clinical retrospective analysis.

OBJECTIVES: To (a) evaluate the interpolation frames of frame rate conversion (FRC) compared with fluoroscopic frames of conventional method, and (b) compare radiation dose and fluoroscopy time between various clinical examinations without and with FRC retrospectively. METHODS: This study consisted of a basic study and a clinical retrospective analysis. The radiation dosimetry, visual assessment and measurements of contrast to noise ratio were examined. Similarity between interpolation frames and fluoroscopic frames was evaluated using normalised cross-correlation values. In the clinical retrospective analysis approved by the institutional review board, we extracted 270 examinations performed without FRC (conventional group, 12.5 pulses/s) and with FRC (FRC group, 6.25 pulses/s) from 23 May to 31 December 2016. The fluoroscopy parameters and demographics of the two groups of the clinical examinations were compared. Statistical analyses were performed with Wilcoxon signed-rank test, Brunner-Munzel test and χ2 test. RESULTS: In the basic study, the only significant difference was that the radiation dose of FRC was approximately half that of the conventional method in the same fluoroscopy time (p = .031). The interpolation frames of FRC were similar to the fluoroscopic frames of the conventional method. In the clinical retrospective analysis, the only significant difference was that FRC reduced the fluoroscopy dose by 48% and the total dose by 31% compared with the conventional method (p < .001). There was no significant difference in the others. CONCLUSION: FRC significantly reduced the radiation dose without extending the fluoroscopy time and maintaining the image quality compared to the conventional method. KEY POINTS: • Although X-ray fluoroscopic techniques are widely used for various clinical purposes, X-ray fluoroscopic examinations have radiation risks. • Frame rate conversion is an image processing technique for radiation dose reduction. • Clinical retrospective analysis showed that FRC reduces radiation doses of patients.

Computer-Assisted Instrument Navigation Versus Conventional C-Arm Fluoroscopy for Surgical Instrumentation: Accuracy, Radiation Time, and Radiation Exposure.

OBJECTIVE. Compared with open procedures, minimally invasive surgical procedures are associated with increased radiation exposure and long-term health risks. Ultralow radiation imaging coupled with image enhancement and instrument tracking (ULRI-IE/IT) is a new image modifier that allows a computer to show real-time movement of an instrument as it is adjusted, mimicking live fluoroscopy but without continuous radiation production. The purpose of this study was to determine the accuracy and radiation output of ULRI-IE/IT compared with unassisted conventional fluoroscopy in a variety of surgical procedures. MATERIALS AND METHODS. Physicians of various specialties were asked to identify the ideal location for instrumentation in various spinal, orthopedic, pain, and physiatric procedures and then place an instrument in this location in a cadaver both with and without ULRI-IE/IT assistance. Whether ULRI-IE/IT was used was randomly assigned to reduce the impact of learning. Radiation exposure, time to place the instrument, and the number of images required to achieve accurate positioning were recorded for each procedure. These were compared for unassisted and ULRI-IE/IT-assisted fluoroscopy to determine the utility of ULRI-IE/IT in minimally invasive instrumentation. RESULTS. Twenty-three trials of nine procedures by five physicians were completed both with and without assistance of ULRI-IE/IT. The procedures ranged from percutaneous pedicle screw insertion to foramen ovale ablation. Total time to localize the instrument for all 23 cases was 31.2% longer without assistance. Use of ULRI-IE/IT reduced the total number of images per case by 74.8% and radiation exposure by 91.8%. With ULRI-IE/IT, physicians were able to successfully place the instrument in the correct location on the first attempt in 82.6% of trials and in the second attempt in all trials versus a mean of 4.65 images needed for unassisted fluoroscopy. CONCLUSION. Use of ULRI-IE/IT can dramatically reduce radiation output and the number of images acquired and time required to perform fluoroscopic procedures.

Fusion Imaging for EVAR with Mobile C-arm.

BACKGROUND: Fusion imaging is a technique that facilitates endovascular navigation but is only available in hybrid rooms. The goal of this study was to evaluate the feasibility of fusion imaging with a mobile C-arm in a conventional operating room through the use of an angionavigation station. METHODS: From May 2016 to June 2017, the study included all patients who underwent an aortic stent graft procedure in a conventional operating room with a mobile flat-panel detector (Cios Alpha, Siemens) connected to an angionavigation station (EndoNaut, Therenva). The intention was to perform preoperative 3D computerized tomography/perioperative 2D fluoroscopy fusion imaging using an automatic registration process. Registration was considered successful when the software was able to correctly overlay preoperative 3D vascular structures onto the fluoroscopy image. For EVAR, contrast dose, operation time, and fluoroscopy time (FT) were compared with those of a control group drawn from the department's database who underwent a procedure with a C-arm image intensifier. RESULTS: The study included 54 patients, and the procedures performed were 49 EVAR, 2 TEVAR, 2 IBD, and 1 FEVAR. Of the 178 registrations that were initialized, it was possible to use the fusion imaging in 170 cases, that is, a 95.5% success rate. In the EVAR comparison, there were no difference with the control group (n = 103) for FT (21.9 ± 12 vs. 19.5 ± 13 min; P = 0.27), but less contrast agent was used in the group undergoing a procedure with the angionavigation station (42.3 ± 22 mL vs. 81.2 ± 48 mL; P < 0.001), and operation time was shorter (114 ± 44 vs. 140.8 ± 38 min; P < 0.0001). CONCLUSIONS: Fusion imaging is feasible with a mobile C-arm in a conventional operating room and thus represents an alternative to hybrid rooms. Its clinical benefits should be evaluated in a randomized series, but our study already suggests that EVAR procedures might be facilitated with an angionavigation system.

Comparison of intraoperative radiation exposure with and without use of distal targeting device: a randomized control study.

INTRODUCTION: When locking intramedullary nails, inserting the distal interlocking screw accurately and quickly with less radiation exposure is very important. The purpose of this randomized control study was to compare radiation exposure and accuracy of distal locking screws between free-hand fluoroscopic guidance and the use of a distal targeting system (DTS). MATERIALS AND METHODS: Inclusion criteria of this study were patients older than 60 years who need an intramedullary nailing due to unstable intertrochanteric and subtrochanteric fracture. The primary outcome was the attempt numbers of image intensifier during the insertion of distal locking screws. Secondary outcomes were operative time and angles between distal locking screws and nail. RESULTS: A total of 36 patients participated in the study. Eighteen patients using free-hand fluoroscopic guidance were assigned to Group I while 18 patients using DTS were assigned to Group II. The number of attempts of image intensifier during distal screw insertion (57.3 ± 31.42 vs. 11.5 ± 7.41, p < 0.001), ratio of attempt number for distal screws to the total attempts (0.33 ± 0.21 vs. 0.12 ± 0.08, p = 0.001), the number of hand exposure to image intensifier directly (75.0 ± 29.55 vs. 13.5 ± 19.07, p < 0.001), and the time of radiation exposure during distal screws insertion (42.57 ± 2.42 s vs. 12.72 ± 8.10 s, p < 0.001) were significantly lower in Group II compared to those in Group I. And, operation time (96.3 min ± 18.94 vs. 76.1 min ± 14.10, p < 0.001) was also statistically significantly lower in Group II. Both distal locking screws were significantly closer to perpendicular direction to the nail in Group II. CONCLUSION: The attempt number of image intensifier during the insertion of two distal locking screws was significantly reduced with DTS compared with that with free hand fluoroscopic guidance. Angle between distal locking screws and nail was also more accurate using DTS.

Diagnostic accuracy of dermatofluoroscopy in cutaneous melanoma detection: results of a prospective multicentre clinical study in 476 pigmented lesions.

BACKGROUND: Early detection is a key factor in improving survival from melanoma. Today, the clinical diagnosis of cutaneous melanoma is based mostly on visual inspection and dermoscopy. Preclinical studies in freshly excised or paraffin-embedded tissue have shown that the melanin fluorescence spectra after stepwise two-photon excitation, a process termed dermatofluoroscopy, differ between cutaneous melanoma and melanocytic naevi. However, confirmation from a larger prospective clinical study is lacking. OBJECTIVES: The primary end point of this study was to determine the diagnostic accuracy of dermatofluoroscopy in melanoma detection. Secondary end points included the collection of data for improving the computer algorithm that classifies skin lesions based on melanin fluorescence and the assessment of safety aspects. METHODS: This was a prospective, blinded, multicentre clinical study in patients with pigmented skin lesions (PSLs) indicated for excision either to rule out or to confirm cutaneous melanoma. All included lesions underwent dermoscopy and dermatofluoroscopy in vivo before lesions were excised and subjected to histopathological examination. RESULTS: In total, 369 patients and 476 PSLs were included in the final analysis. In 101 of 476 lesions (21·2%) histopathology revealed melanoma. The observed sensitivity of dermatofluoroscopy was 89·1% (90 of 101 melanomas identified), with an observed specificity of 44·8%. The positive and negative predictive values were 30·3% and 93·9%, respectively. No adverse events occurred. CONCLUSIONS: Dermatofluoroscopy is a safe and accurate diagnostic method to aid physicians in diagnosing cutaneous melanoma. Limitations arise from largely amelanotic or regressing lesions lacking sufficient melanin fluorescence.

A pilot single-center prospective randomized trial to assess the short-term effect of a flashing warning light on reducing fluoroscopy time and radiation exposure during ERCP.

BACKGROUND AND AIMS: ERCP has the risk of exposure to ionizing radiation. Performers may unconsciously increase fluoroscopy time (FT) because of a lack of radiation protection awareness. This study investigates whether a flashing warning light adopted as a behavioral intervention for performers reduces FT and radiation exposure during ERCP. METHODS: We conducted a prospective randomized trial of 200 therapeutic ERCPs. A flashing warning light was placed on top of the endoscopy monitor. Cases were consecutively enrolled and randomly assigned to 2 groups in a 1:1 ratio. In the warning light group, the light was on when the fluoroscopy foot pedal was depressed; in the control group, the light was off. Fluoroscopy and procedure-related data were recorded. RESULTS: The median FT and dose-area product (DAP) for the warning light group versus the control group were 142.5 seconds versus 175.0 seconds (P = .045) and 856.8 µGy∙m2 versus 1054.4 µGy∙m2 (P = .043). In a multivariable analysis, the use of the warning light was found to reduce FT by 15.4% (-27.0 seconds; P = .042). DAP reduction because of the decreased FT was 15.2% (160.3 µGy∙m2). The reduction in patient effective dose per case was .42 mSv, equivalent to 21 chest radiographs. No adverse events or interference with the procedures because of the warning light were noted. CONCLUSIONS: The use of a flashing warning light is a feasible way to reduce FT and radiation exposure during ERCP. (Clinical trial registration number: ChiCTR-IPR-14005349.).

Variability in radiation dose and image quality: A comparison across fluoroscopy-system vendors, generations of equipment and institutions.

OBJECTIVES: To evaluate differences in radiation dose and image quality across institutions, fluoroscope vendors and generations of fluoroscopes for pediatric cardiac catheterization. BACKGROUND: Increased recognition of the potentially harmful effects of ionizing radiation has spurred technological advances in fluoroscopes, as well as increased focus on optimizing fluoroscope performance. There is currently little understanding of variability in the dose-image quality relationship across institutions, fluoroscope vendor and/or generation of equipment. METHODS: We evaluated latest generation fluoroscopes from Phillips, Siemens, GE, and Toshiba, and an older generation Phillips fluoroscope (release date 2003) at three different institutions. Radiation dose was measured using an anthropomorphic dose-assessment phantom with effective dose in mSv estimated from Monte Carlo simulations. Image quality phantom images were scored on a 12-point scale by three blinded reviewers. RESULTS: Fluoroscope effective doses ranged from 0.04 to 0.14 mSv/1,000 pulses for fluoroscopy with associated composite image quality scores ranging from 8.0 ± 0.6 to 10.4 ± 1.3. For cineangiography, effective doses ranged from 0.17 to 0.57 mSv/1,000 frames with image quality scores ranging from 10.1 ± 0.3 to 11.1 ± 0.3. There was modest correlation between effective dose and image quality (r = 0.67, P = 0.006). The older generation fluoroscope delivered consistently higher doses than the newer generation systems (2.3- to 3.5-fold higher for fluoroscopy; 1.1- to 3.4-fold higher for cineangiography) without appreciable differences in image quality. CONCLUSION: Technological advances have markedly improved fluoroscope performance. Comparing latest generation systems across vendors and institutions, we found variability in the dose-IQ relationship and speculate that this reflects both equipment and institutional optimization practices.

Comparison of Radiation Exposure during Endovascular Treatment of Peripheral Arterial Disease with Flat-Panel Detectors on Mobile C-arm versus Fixed Systems.

BACKGROUND: Flat-panel detectors on mobile C-arm (MC-arm) systems are currently challenging fixed C-arm (FC-arm) systems used in hybrid operating rooms. MC-arm systems offer an alternative to FC-arm systems in the endovascular treatment of peripheral arterial disease (PAD) but their efficiency has not been evaluated comparatively. METHODS: Two series of patients undergoing arteriography with intention to treat were included. Each series consisted of 2 nonrandomized groups: an MC-arm group and an FC-arm group. Series 1 evaluated exposure to the patient (MC-arm, n = 113; FC-arm, n = 206) while series 2 evaluated exposure to patients and also health care personnel (MC-arm, n = 24; FC-arm, n = 76). The primary end points for evaluating exposure were air kerma (AK, in mGy) for patients and effective dose for health care personnel (in µSv). RESULTS: After adjustment for the effect of body mass index (analysis of covariance test), AK was found to be lower in the MC-arm group than in the FC-arm group (124.1 ± 142 vs. 173.3 ± 248.7, P = 0.025). There was no difference between the groups with regard to effective dose recorded for senior surgeons or for operating room nurses. However, a higher effective dose was recorded by the MC-arm group external dosimeter for the trainee resident and for nurse anesthetists. CONCLUSIONS: In endovascular treatment of lower limb PAD, use of an FC-arm system is associated with more radiation exposure to the patient than an MC-arm system. However, this type of imaging system does not appear to affect exposure to health care personnel.

The use of needle holders in CTF guided biopsies as a dose reduction tool.

PURPOSE: The purpose of this study was to evaluate the efficacy of needle holders in reducing staff hand exposure during biopsies guided by computed tomography fluoroscopy (CTF), through the analysis of data acquired during a detailed monitoring study, undertaken in parallel with an ongoing optimization process to reduce hand irradiation. METHODS: Hand monitoring was performed with 11 extremity detectors, two per finger (base and tip) and one on the back of the wrist, for the left (dominant) hand, during two series of biopsies with comparable characteristics. The first series (47 biopsies) were performed with only quick-check method (QC) and occasional side-handle (SH) manipulation of the needle. The second series (63 biopsies) were performed after introducing needle holders (NH) in the course of an optimization process. RESULTS: Choice of technique (QC, QC + NH, QC + SH) by the interventional radiologist (IR) was related to biopsy difficulty. Measured hand exposure was low (< 1 mSv) for all QC-only procedures, and for most of the QC + NH procedures. Occasional side-handle manipulation still occurred during challenging biopsies, so that 8% of biopsies in the second series accounted for ~70% of total fingertip dose (~90 mSv). The methodology used allowed a detailed insight into the dose reduction achievable with needle holders during real procedures, without the limitations of phantom measurements. CONCLUSIONS: Needle holders proved effective in reducing mean hand exposure during clinical procedures where real-time manipulation was necessary. Occasional side-handle manipulation was found to contribute disproportionately to hand exposure. This highlights the importance of individual hand monitoring during CTF guided procedures.

Validation of a Simple Overlay Device to Assess Radial Head Implant Length.

PURPOSE: A simple overlay device (SOD) was developed to measure radial head implant length. The purpose of this study was to determine the accuracy and reliability of this device for measuring experimental radial head implant length. METHODS: Five fresh frozen cadavers were implanted with sequentially longer implants, adjusted by neck length (0, 2, 4, and 8 mm). Fluoroscopic images were obtained in 4 forearm positions: anteroposterior in supination in full extension, anteroposterior in pronation in full extension, supinated in 45° of flexion, and neutral in 45° of flexion. The SOD measurements (made by 2 observers) were compared with the native original radial head (control) to assess implant length. In addition, gapping of the ulnohumeral joint space was measured for comparison purposes. RESULTS: The measured radial head and neck lengths for the specimens were 33, 39, 31, 34, and 42 mm. The difference between the actual radial head and neck lengths and those measured with the SOD template averaged less than 2 mm for all 4 collar sizes, except in 1 measurement in which the bicipital tuberosity could not be visualized. The median intraclass correlation coefficients for observer 1 compared with the SOD were 0.94 to 0.99. The median intraclass correlation coefficients between observers were 0.88 to 0.95. For both observers, elbow position, collar height, and the 2 variables combined did not significantly affect the SOD values. The other method that was evaluated, that of measurement of the ulnohumeral joint space, had higher interobserver variability versus the SOD, and allowed detection of lengthening of over 4 mm. CONCLUSIONS: The SOD is a reliable method for simply assessing radial head length with radiographs and can accurately detect 2 mm or more of proximal radial lengthening. CLINICAL RELEVANCE: The SOD is a simple and accurate method that can help to optimize radial head sizing.

Use of a 3D-Printed Abdominal Compression Device to Facilitate CT Fluoroscopy-Guided Percutaneous Interventions.

OBJECTIVE: The purpose of this article is to describe a handheld external compression device used to facilitate CT fluoroscopy-guided percutaneous interventions in the abdomen. CONCLUSION: The device was designed with computer-aided design software to modify an existing gastrointestinal fluoroscopy compression device and was constructed by 3D printing. This abdominal compression device facilitates access to interventional targets, and its use minimizes radiation exposure of radiologists. Twenty-one procedures, including biopsies, drainage procedures, and an ablation, were performed with the device. Radiation dosimetry data were collected during two procedures.

Radiation exposure using the O-arm® surgical imaging system.

PURPOSE: This study was conducted to characterise the O-arm® surgical imaging system in terms of patient organ doses and medical staff occupational exposure during three-dimensional thoracic spine and pelvic examinations. METHODS: An anthropomorphic phantom was used to evaluate absorbed organ doses during a three-dimensional thoracic spine scan and a three-dimensional pelvic scan with the O-arm®. Staff occupational exposure was evaluated by constructing an ambient dose cartography of the operating theatre during a three-dimensional pelvic scan as well as using an anthropomorphic phantom to simulate the O-arm® operator. RESULTS: Patient organ doses ranged from 30 ± 4 µGy to 20.0 ± 3.0 mGy and 4 ± 1 µGy to 6.7 ± 1.0 mGy for a three-dimensional thoracic spine and pelvic examination, respectively. For a single three-dimensional acquisition, the maximum ambient equivalent dose at 2 m from the iso-centre was 11 ± 1 µSv. CONCLUSION: Doses delivered to the patient during a three-dimensional thoracic spine image acquisition were found to be significant with the O-arm®, but lower than those observed with a standard computed tomography examination. The detailed dose cartography allows for the optimisation of medical staff positioning within the operating theatre while imaging with the O-arm®.

Modifications to advanced Core decompression for treatment of Avascular necrosis of the femoral head.

BACKGROUND: "Advanced Core Decompression" (ACD) is a new technique for treatment of osteonecrosis of the femoral head (ONFH) that includes removal of the necrotic tissue using a percutaneous expandable reamer followed by refilling of the drill hole and the defect with an injectable, hard-setting, composite calcium sulphate (CaSO4)-calcium phosphate (CaPO4) bone graft substitute. As autologous bone has been shown to be superior to all other types of bone grafts, the aim of the study is to present and evaluate a modified technique of ACD with impaction of autologous bone derived from the femoral neck into the necrotic defect. METHODS: A cohort of patients with an average follow-up of 30.06 months (minimum 12 months) was evaluated for potential collapse of the femoral head and any reasons that led to replacement of the operated hip. Only patients in stages 2a to 2c according to the Steinberg classification were included in the study. RESULTS: In 75.9% the treatment was successful with no collapse of the femoral head or conversion to a total hip replacement. Analysis of the results of the different subgroups showed that the success rate was 100% for stage 2a lesions and 84.6% respectively 61.5% for stages 2b and 2c lesions. CONCLUSIONS: Previous studies with a comparable follow-up reported less favourable results for ACD without autologous bone. Especially in stages 2b and 2c the additional use of autologous bone has a positive effect. In comparison to other hip-preserving techniques, the modified ACD technique is a very promising and minimally invasive method for treatment of ONFH. TRIAL REGISTRATION: German clinical trials register ( DRKS00011269 , retrospectively registered).

Dose-Decreasing Effect of the First Reversed Laser Beam Collimator for C-Arm Type Angiographic Equipment.

This is a study on the dose-decreasing effect of the first reversed laser beam collimator (RLBC) for C-arm type angiographic equipment. A laser beam was located at the center of each plane at an oblique angle to the angiographic equipment detector. A field of view, which could be seen with the naked eye, was made by focusing the laser beam in the direction of the X-ray source. The height of the table was fixed at 75 cm and the iron balls were located within 2 mm of the top, bottom, left, and right edges of the output image. The time needed for location fixing, fluoroscopy, and measurement of dose area product (DAP) were compared by having 30 radiologists perform location fixing by looking at the fluoroscopic image while performing location fixing (no radiation) and while the RLBC was turned on. In the next test, the time needed for location fixing, fluoroscopy, and DAP were compared when varying the location of the iron balls from 2 to 10 mm from the edges of the output image. The results showed that the time needed for location fixing, the time needed for fluoroscopy, and DAP decreased, both in the first test and the second test. This study confirmed that the use of a RLBC for C-arm type angiographic equipment decreases both the time needed to perform the procedure and the radiation dose received. It is expected that continuous advancement of RLBC technology will contribute greatly to decreasing the dose of radiation needed and improving convenience during angiography.