Minimize Radiation Exposure Research Articles

Strategies for radiation exposure-sparing in fluoroscopically guided invasive cardiovascular procedures.

Minimizing radiation exposure during x-ray fluoroscopically guided procedures is critical to patients and to medical personnel. Tableside adjustment of x-ray image acquisition parameters can vary the fluoroscopic radiation exposure rate. To determine the impact of adjusting four tableside controllable image acquisition parameters on x-ray fluoroscopic radiation exposure rate. We made fluoroscopic exposures of a standard radiologic phantom to measure radiation exposure rates as kerma•area product per second of exposure and milligray per x-ray pulse under all possible combinations of detector zoom mode, collimated image field size, fluoroscopy dose mode, and fluoroscopy pulse frequency. Kerma•area product per second was linearly proportional to pulse frequency. Selecting larger detector zoom modes, smaller collimated image field sizes and low dose fluoroscopy mode each decreased exposure rate. We found a > 20-fold variation in dose rates over the range of acquisition parameter combinations. Selecting the most appropriate fluoroscopy acquisition parameters enables physician operators to adjust radiation exposure rates over a large range. Judicious selection of acquisition parameters can reduce patient and medical personnel radiation exposure by as much as 95% compared to "standard" fluoroscopy protocol settings.

Abstract 142: Feel the Burn, PCI Advances Increase Radiation Exposure of Patients

Objective: Interventional cardiology success in revascularization and structural heart has an unseen cost. Complex, prolonged cases increase exposure of patients (Pts) and staff to ionizing radiation. The increased radiation has direct deterministic effects (air kerma; skin dose) and stochastic effects (air kerma x area product). Fluoro time is also monitored. Individual MD and overall lab perfomance exposure guidelines for the laboratory have been set [peak Skin dose < 5 Gray, Air kerma x Area product (DAP) < 200 Gray*cm 2 , fluoro time < 60 min). Procedure: Exposure for cath pts was tracked. MD, pt, anatomic, procedural variables associated with high exposures were identified and specific interventions to minimize radiation exposure identified. Results: Over a year period 17.2% of cases [237/1375] received high skin [6.0%; 83/1375] or DAP radiation [17.2%; 237/1375]. No pt sequelae were identified on follow-up for doses as high as 13.251 Gray, 775 Gy*cm2, fluoro time 119.9 min. Fluoro time was not a useful measure; it did not correlate with either skin dose or DAP, reflecting variable use of fluoro compared to cine, pt BMI, differing fluoro rates (ranging from 4 fps to 15 fps). Frequency of high radiation exposure by MD (with over 50 cases/year) ranged from 4.5% - 28.3% of interventions [Skin dose 1.1%-15.4% and DAP 4.5%-28.3%]. Pt risk factors included: morbid obesity, multivessel/multilesion interventions, lesion complexity [particularly calcified lesions and CTOs], complex structural heart procedures. MD factors included: highly angled views, # of cine runs [8.9% (122/1375) > 40 runs, 3.7% (51/1375) > 50 runs, 0.8% 14/1375) > 75 runs], staged procedures versus multivessel/ multilesion procedures, trainee staffing. Default radiation exposure settings of Xray equipment are now set at lower levels acceptable for imaging (MD can modify). MD feedback and interventions to decrease radiation exposure are ongoing, targeting: MD continued case awareness of displayed radiation dose with appropriate staging, use of lowest visually acceptable fluoro rates, shortening and minimizing cine runs where possible, store/map reference images, vary imaging angle and decrease where possible steep angulations, optimal collimation. The MDs who have adopted these practices have the lowest pt exposure rates [skin dose 1.4-5.1%, DAP 4.5-8.6% guideline tracked]. Opportunities for improvement are evident in current practice but also include improved tracking of pt medical treatment related exposure, upgrades in Xray equipment. Conclusions: Advances in equipment and MD experience have been offset by the increasing disease complexity of attempted interventions [including CTOs]. Pt factors and MD practice both contribute to optimal radiation safety [ALARA]. MD practice is a key modifiable variable to promote radiation safety, affecting exposure of pts and staff.

Radiation Training, Radiation Protection, and Fluoroscopy Utilization Practices Among US Therapeutic Endoscopists.

Fluoroscopy use during ERCP exposes patients and providers to deleterious effects of radiation. Formal training in fluoroscopy/radiation protection is not widely emphasized during therapeutic endoscopy training, and radiation use during GI endoscopy has not previously been characterized in the USA. In this study, we evaluated radiation training, fluoroscopy use patterns, and radiation protection practices among US therapeutic endoscopists. An anonymous electronic survey was distributed to US therapeutic endoscopists, and responses were analyzed using descriptive statistics. State-specific requirements for fluoroscopy utilization were determined from state radiologic health branches. A total of 159 endoscopists (response rate 67.8%) predominantly those working in university hospitals (69.2%) with > 5years of experience performing ERCP (74.9%) completed the questionnaire. Although the majority of endoscopists (61.6%) reported that they personally controlled fluoroscopy during ERCP, most (56.6%) had not received training on operating their fluoroscopy system. Only a minority (18-31%) of all respondents reported consistently utilizing modifiable fluoroscopy system parameters that minimize patient radiation exposure (pulsed fluoroscopy, frame rate modification or collimation). Endoscopists appear to undertake adequate personal radiation protective measures although use of a dosimeter was not consistent in half of respondents. The majority of states (56.8%) do not have any stated requirement for certification of non-radiologist physicians who intend to operate fluoroscopy. Most US gastroenterologists performing ERCP have not received formal training in operating their fluoroscopy system or in minimizing radiation exposure to themselves and to their patients. Such formal training should be included in all therapeutic endoscopy training programs, and fluoroscopy system-specific training should be offered at all hospitals.

Four-dimensional CT as a valid approach to detect and quantify kinematic changes after selective ankle ligament sectioning

The objective of the current study was to explore the potential of dynamic computed tomography to detect kinematic changes, induced by sequential sectioning of the lateral collateral ligaments of the ankle, during full motion sequence of the talocrural joint. A custom-made device was used to induce cyclic controlled ankle inversion movement in one fresh frozen cadaver leg. A 256-slice CT scanner was used to investigate four different scenarios. Scenario 1 with all ligaments intact was first investigated followed by sequential section of the anterior talo-fibular ligament (Scenario 2), the calcaneo-fibular ligament (Scenario 3) and posterior talo-fibular ligament (Scenario 4). Off-line image processing based on semi-automatic segmentation and bone rigid registration was performed. Motion parameters such as translation, rotational angles and orientation and position of the axis of rotation were calculated. Differences between scenarios were calculated. Progressive increase of cranio-caudal displacement up to 3.9 mm and flexion up to 10° compared to Scenario 1 were reported. Progressive changes in orientation (up to 20.6°) and position (up to 4.1 mm) of the axis of rotation were also shown. Estimated effective dose of 0.005 mSv (1.9 mGy CTDIvol) was reported. This study demonstrated that kinematic changes due to the absence of ligament integrity can be detected with 4DCT with minimal radiation exposure. Identifying abnormal kinematic patterns could have future application in helping clinicians to choose patients’ optimal treatment. Therefore, further studies with bigger in vitro sample sizes and consequent investigations in vivo are recommended to confirm the current findings.

Слот-рентгенография. Новые возможности лучевой диагностики

Slot-radiography is an x-ray examination in which a two-dimensional radiography with a straight beam and further computer stitching of the images obtained on the workstation during a single-pass of x-ray tube over a patient. The application of innovative techniques for image acquisition and processing in combination with a large-area flat panel detector (FPD) makes it possible to produce long-view images from one to several anatomical regions. During the investigation, the x-ray tube and the FPD move simultaneously at a constant speed in parallel relative to one another with the longitudinal axis of the body. Thus, it makes possible to obtain images with little distortion and processed images without visual defects. And this allows conducting more accurate diagnosis of pathological changes. Slot-radiography can be performed both in the patient’s standing position and lying down depending on the region of interest and tasks. It is possible to obtain images in both a frontal and a lateral projection without loss of quality.
 Slot-radiography is effectively used to diagnose pathological changes in joints and spine, including scoliosis, limb shortening, segmental spinal instability, pathology of lower limb veins, and also as a method for assessing the quality of the treatment. This technique is characterized by safety and convenience for the patient: minimal time costs and low radiation exposure.
 The application of this technique significantly increases the informative value of the x-ray examination, brings it to a qualitatively new level, providing a physician with a wide range of diagnostic possibilities.

Procedural determinants of fluoroscopy time in patients undergoing cardiac catheterization.

Background & Objective:Due to increase in number of cardiac catheterization procedures safety concerns is an issue nowadays. Multiple diagnostic modalities use radiations, which also put a patient at higher cumulative radiation exposure. Therefore steps should be taken to minimize radiation exposure during cardiac catheterization. Hence determination of factors which prolong FT will result in better understanding of problem. This retrospective study was undertaken to determine factors responsible for prolong fluoroscopy time in patients undergoing coronary artery catheterization.Methods:This retrospective study was conducted at catheterization Laboratory National Institute of Cardiovascular Diseases, Karachi from June 2014 to June 2015. Patients of either gender, aged between 18 to 90 years undergoing cardiac catheterization procedures were included. Radiation exposure time was measured in terms of fluoroscopy time.Results:A total of 957 patients were included in this study out of which 731 were of diagnostic Coronary Angiograms (CA) and 226 were of Percutaneous Coronary Intervention (PCI). The mean age of the study participants was 54.12±10.89 years and majority 734(76.6%) were male. Mean fluoroscopy time (FT) in the patients subjected to PCI was 9.61±6.07 minutes while in cases for CA 4.17±4.13 minutes. FT for CA was observed significantly dependent on procedural access, operator’s experience, and LV angiogram. While FT for PCI was found dependent on number of stents deployed during the procedure.Conclusion:For invasive coronary angiographic procedures radial route increased fluoroscopy time. For percutaneous coronary intervention femoral and radial route fluoroscopy time were not significantly different.

Application of dextran-coated iron oxide nanoparticles in enhancing the radiosensitivity of cancerous cells in radiotherapy with high-energy electron beams.

Nowadays, cancer is one of the most important causes of morbidity and mortality in the world. The ideal aim of radiotherapy is delivering a lethal radiation dose to tumor cells while minimizing radiation exposure to healthy tissues around the tumor. One way to increase the dose in the tumor cells is the use of high-atomic number nanoparticles as radiosensitizer agents in these cells. The aim of this in vitro study was investigating the radiosensitization enhancement potential of the dextran-coated iron oxide nanoparticles (IONPs) on HeLa and MCF-7 cell lines in irradiations with high-energy electron beams. In this in vitro study, the cytotoxicity level of dextran-coated IONPs at different concentrations (10, 40, and 80 μg/ml) was assessed on HeLa and MCF-7 cell lines. To evaluate the radiosensitivity effect, the nanoparticles were incubated with the cells at different concentrations for 24 h and afterward irradiated with different doses (0, 2, 4, 6, and 8 Gy) of 6 and 12 MeV electron beams. The cells survival fractions were obtained by the methylthiazoletetrazolium assay. Toxicity results of the nanoparticles at 10 and 40 μg/ml concentrations showed no significant cytotoxicity effect. The cells survival rates in groups receiving radiation in the absence and presence of IONPs showed a significant difference. The radiosensitivity enhancement induced by the nanoparticles in MCF-7 cell line was more than it in HeLa cell line. The average of radiosensitization enhancement factor at 10, 40, and 80 μg/ml concentrations and under 6 MeV irradiations obtained as 1.13, 1.19, 1.25, and 1.26, 1.28, 1.29 for HeLa, and MCF-7 cells, respectively. When 12 MeV electron beams were carried out, the values of 1.17, 1.26, 1.32, and 1.29, 1.32, 1.35 were obtained for the cells at the mentioned concentrations, respectively. Furthermore, the significant differences were observed in radiosensitization enhancement between 6 and 12 MeV electron beams irradiations. Use of dextran-coated IONPs can increase radiosensitivity and consequently at a given absorbed dose more cell killing will occur in cancerous cells. In other words, these nanoparticles can improve the efficiency of electron therapy.

First spine surgery utilizing real-time image-guided robotic assistance

Robotics in spinal surgery has significant potential benefits for both surgeons and patients, including reduced surgeon fatigue, improved screw accuracy, decreased radiation exposure, greater options for minimally invasive surgery, and less time required to train residents on techniques that can have steep learning curves. However, previous robotic systems have several drawbacks, which are addressed by the innovative ExcelsiusGPSTM robotic system. The robot is secured to the operating room floor, not the patient. It has a rigid external arm that facilitates direct transpedicular drilling and screw placement, without requiring K-wires. In addition, the ExcelsisuGPSTM has integrated neuronavigation, not present in other systems. It also has surveillance marker that immediately alerts the surgeon in the event of loss of registration, and a lateral force meter to alert the surgeon in the event of skiving. Here, we present the first spinal surgery performed with the assistance of this newly approved robot. The surgery was performed with excellent screw placement, minimal radiation exposure to the patient and surgeon, and the patient had a favorable outcome. We report the first operative case with the ExcelsisuGPSTM, and the first spine surgery utilizing real-time image-guided robotic assistance.

Commissioning of two different algorithms for stereotactic Radiosurgery M6 FI+ CyberKnife system

Introduction: Cyber Knife M6 FI+ a very precise robotic stereotactic radiosurgery system which is capable of delivering very high radiation dose to the tumour while minimizing radiation exposure to normal organs and tissues. MultiPlan treatment planning system is used with the CyberKnife unit and the algorithms used for optimization are Ray-Tracing and Monte Carlo. Our CyberKnife M6 FI+ system commissioning is done as per the vendor recommendation and meeting the local regulatory guidelines. Materials and Methods: Clinical beam data measurement is carried out using Radiation Field Analyzer, Diode E, Pinpoint chamber, Semiflex ionization chamber and Unidose E Electrometer. FC-65 ionization chamber used in absolute dose calibration. The mechanical accuracy of the robot and image stability was verified using Radiochromic film (EBT3), E2E and Iris QA toolkits along with software. StereoPHAN is used for the patient-specific QA point dose measurement. Results: Tissue phantom ratio, Off-centre ratio, Output factor, Percentage depth dose, open beam profile and absolute dose calibration are done as per the protocols. E2E performed for two different modes- static and motion. Iris aperture size measured for all the field sizes. The patient-specific QA delivered for both algorithms. Discussion: Clinical beam data measurements are within ±1% of composite data set, overall standard deviation for Output Factors of the fixed and Iris collimators are 0.0026 and 0.0063. The absolute dose was calibrated to 1cGy per MU. E2E, Iris QA and Laser and radiation coincidence values are within the tolerance. Patient-specific QA point dose measurement variation for Ray-Tracing and Monte Carlo is 3% and 2%. Conclusion: These exercises are mandatory to achieve the accurate, precise and high quality of treatment which also includes patient safety.

Working Cannula-Based Endoscopic Foraminoplasty: A Technical Note.

Purpose Percutaneous endoscopic lumbar discectomy (PELD) is a minimally invasive disc surgery that can be performed under local anesthesia and requires only an eight-mm skin incision. For the patients with lumbar foraminal stenosis, the migrated disc is difficult to remove with a simple transforaminal approach. In such cases, the foraminoplasty techniques can be used. However, obtaining efficient foramen enlargement while minimizing radiation exposure and protecting the nerves can be challenging. Methods In this study, we propose a new technique called the Kiss-Hug maneuver. Under endoscopic viewing, we used the bevel tip of a working cannula as a bone reamer to enlarge the foramen. This allowed us to efficiently enlarge the lumbar foramen endoscopically without the redundancy and complications associated with reamers or trephines. Results Details of the four steps of the Kiss-Hug maneuver are reported along with adverse events. The advantages of this new technique include minimizing radiation exposure to both the surgeon and the patient and decreasing the overall operation time. Conclusion The endoscopic Kiss-Hug maneuver is a useful and reliable foraminoplasty technique that can enhance the efficiency of foraminoplasty while ensuring patient safety and reducing radiation exposure.

Reducing Radiation Exposure in Cardiac Catheterizations for Congenital Heart Disease.

Ionizing radiation exposure is a necessary risk entailed during congenital cardiac catheterizations. The congenital catheterization lab at Yale New Haven Children's Hospital employed quality improvement strategies to minimize radiation exposure in this vulnerable population. In two phases, we implemented six interventions, which included adding and utilizing lower fluoroscopy and digital angiography (DA) doses, increasing staff and physician radiation awareness, focusing on tighter collimation, and changing the default fluoroscopy and DA doses to lower settings. Post-intervention data were collected prospectively for all procedures in the congenital catheterization lab and compared to pre-intervention radiation data collected retrospectively. Radiation exposure was measured in total air kerma (mGy), dose area product per body weight (DAP/kg) (µGym2/kg), and fluoroscopy time (min). Data were collected for a total of 312 cases. In considering all procedures, the DAP/kg decreased by 67.6% and air kerma decreased by 63%. Fluoroscopy time did not change over the study period. Significant decreases in radiation exposure (DAP/kg) by procedure type were seen for atrial septal defect, patent ductus arteriosus, and transcatheter pulmonary valve procedures with a 45%, 42% and 83% decrease, respectively. Air kerma decreased significantly for ASD and PDA procedures with an 80% and 72% decrease, respectively. When compared to national benchmarks, the median DAP/kg and air kerma for these procedures are lower at our institution. The decreases continue to be sustained 2years post-interventions. Systems-based interventions can be readily implemented in the congenital cardiac catheterization lab with dramatic and sustainable radiation dose reduction for patients.

333. A personalized acquisition protocol to optimize 18F-FDG PET/CT whole-body imaging

Purpose PET image quality degradation is encountered in over-weight and obese patients even when administered activity is increased with body weight. For these cases is more appropriate to increase the acquisition time rather than administered activity. Aim of the work is to evaluate a metric related to patient body constitution to optimize 18F-FDG PET/CT Whole-Body (PET-WB) acquisition procedure to guarantee accurate diagnosis with minimal radiation exposure of patients. Methods PET-WB acquisitions were performed with the TruePoint Biograph scanner (Siemens) with 216 mm axial FOV; images were reconstructed with OSEM-3D with 2iterations/8subsets. Initial retrospective analysis was performed on 79 patients studied according to the PET-WB routine protocol: injection of 4.0 ± 0.6 MBq/kg, with a maximum of 500 MBq in obese subjects; acquisition duration of 2 min/bed and 3 min/bed respectively for body weight ⩾ 100 kg. Signal to noise ratio (SNR) measured on liver region was taken as representative parameter of image quality. Diabetic patients and those with hepatic lesions were not included in the analysis. Measured SNR values were normalized to injected activity and acquisition duration (SNRn) and correlated with patient-specific parameters: height to weight ratio (HWR), body mass index (BMI), body surface area (BSA), lean body mass (LBM), fat free mass (FFM). A mathematical model was extrapolated from the parameter most correlated to SNRn values. The developed model was validated prospectively on others 66 patients. Results Retrospective analysis showed a significant SNR decrease with increasing patient size. SNRn values fitted to patient-specific parameters showed the highest R2 (0.86) with HWR. Setting SNR reference value of 9, derived from an image quality deemed acceptable by clinicians for normal-weight patients, the HWR mathematical model allowed to personalize acquisition duration and keep constant image quality for different weight class. By fixing administered maximum activity to 380 MBq for obese subjects an increase of 30% acquisition time corresponded to 30% image SNR gain, with a 30% dose reduction to patient with respect EANM recommendations. Conclusions The application of a model based on specific patient HWR allowed to improve SNR by personalizing acquisition duration without increasing patient dose exposure and to standardize PET-WB procedure.

Interventional 3D Augmented Reality in Orthopedic, Trauma and Vascular Surgery

The Medical Education, Training and Computer Assisted Interventions (METRICS) Laboratory aims to integrate novel mixed-reality technologies with application in computer assisted interventions. We showcase two technologies with specific aims at optimizing surgical workflow and minimizing radiation exposure in orthopedic, trauma, and vascular surgeries. The first is an Augmented Reality C-arm fluoroscope, which provides intuitive real-time visualization by accurately overlaying X-ray to video images. The second is a ‘Desired-views’ user interface which resolves the challenges involved in the optimal control of C-arm fluoroscopes for their constant repositioning during surgery by either the interventionalist or the surgical team.

Full-Dose PET Image Estimation from Low-Dose PET Image Using Deep Learning: a Pilot Study.

Positron emission tomography (PET) imaging is an effective tool used in determining disease stage and lesion malignancy; however, radiation exposure to patients and technicians during PET scans continues to draw concern. One way to minimize radiation exposure is to reduce the dose of radioactive tracer administered in order to obtain the scan. Yet, low-dose images are inherently noisy and have poor image quality making them difficult to read. This paper proposes the use of a deep learning model that takes specific image features into account in the loss function to denoise low-dose PET image slices and estimate their full-dose image quality equivalent. Testing on low-dose image slices indicates a significant improvement in image quality that is comparable to the ground truth full-dose image slices. Additionally, this approach can lower the cost of conducting a PET scan since less radioactive material is required per scan, which may promote the usage of PET scans for medical diagnosis.

National nurse readiness for radiation emergencies and nuclear events: A systematic review of the literature

BackgroundLittle is known regarding the capacity of U.S. nurses to respond following a large-scale radiation release, despite its relevance to our National Security Strategy. PurposeTo conduct a systematic review of the literature to assess nurse readiness for radiation emergencies and nuclear events. MethodsA systematic review of publications identified through a comprehensive search of four relevant databases (Embase, PubMed/Medline, Scopus, and Web of Science) was conducted (n = 62). FindingsLimited evidence exists to support that nurses are prepared or willing to respond to a large-scale emergency resulting from a radiation release or nuclear-level event. DiscussionHistory suggests nurses will be expected to perform triage, minimize radiation exposure, decontaminate, manage trauma, treat burns, and coordinate care for patients. Research is needed to identify the specific roles and responsibilities of nurses in radiation emergencies and nuclear response and to ascertain quantitative measurement of the level of national nurse readiness for these large-scale radiation emergency and nuclear events.

Ultrasound-assisted catheter placement in CT-guided HDR brachytherapy for the local ablation of abdominal malignancies: Initial experience.

To evaluate the safety and feasibility of sonographically-assisted catheter placement in interstitial high-dose-rate brachytherapy of abdominal malignancies. In an initial cohort of 12 patients and 16 abdominal tumors (colorectal liver metastases n = 9; renal cell cancer n = 3; hepatocellular carcinoma n = 2; cholangiocellular carcinoma n = 2), initial puncture and catheter placement for CT-guided brachytherapy were performed under sonographic assistance when possible. The interventional procedure was prospectively recorded and in-patient data were collected. All data underwent descriptive statistics and comparative analysis by the Mann-Whitney test. In 12 out of 16 lesions (diameter 1.5 - 12.9 cm), initial puncture was successfully achieved under ultrasound guidance without utilization of CT fluoroscopy, yielding a significantly shorter mean total fluoroscopy time (14.5 vs. 105.5 s; p = 0.006). In 8 lesions visibility was rated better in ultrasound than in CT fluoroscopy (p = 0.2). No major or minor complications occurred within 30 days after treatment. Ultrasound-assisted catheter placement during interstitial CT-guided brachytherapy of abdominal tumors could improve catheter positioning and reduce radiation exposure for medical staff. Ultrasound-assisted catheter placement in CT-guided brachytherapy is safe and feasible. Ultrasound puncture may improve catheter positioning. Reduced CT fluoroscopy time can significantly help to minimize radiation exposure for medical staff. · Damm R, El-Sanosy S, Omari J et al. Ultrasound-assisted catheter placement in CT-guided HDR brachytherapy for the local ablation of abdominal malignancies: Initial experience. Fortschr Röntgenstr 2019; 191: 48 - 53.

Occupational radiation exposure to nursing staff during cardiovascular fluoroscopic procedures: A review of the literature.

Fluoroscopy is a method used to provide real time x‐ray imaging of the body during medical procedures to assist with medical diagnosis and treatment. Recent technological advances have seen an increase in the number of fluoroscopic examinations being performed. Nurses are an integral part of the team conducting fluoroscopic investigations and are often located close to the patient resulting in an occupational exposure to radiation. The purpose of this review was to examine recent literature which investigates occupational exposure received by nursing staff during cardiovascular fluoroscopic procedures. Articles published between 2011 and 2017 have been searched and comprehensively reviewed on the referenced medical search engines. Twenty‐four relevant studies were identified among which seventeen investigated nursing dose comparative to operator dose. Seven researched the effectiveness of interventions in reducing occupational exposure to nursing staff. While doctors remain at the highest risk of exposure during procedures, evidence suggests that nursing staff may be at risk of exceeding recommended dose limits in some circumstances. There is also evidence of inconsistent use of personal protection such as lead glasses and skull caps by nursing staff to minimize radiation exposure. Conclusions: The review has highlighted a lack of published literature focussing on dose to nurses. There is a need for future research in this area to inform nursing staff of factors which may contribute to high occupational doses and of methods for minimizing the risk of exposure, particularly regarding the importance of utilizing radiation protective equipment.

Mandibular Ramus linear measurements as an Indicator of Chronological Age and Sex in Egyptian Population

Background: The determination of age and sex is crucial for establishing human identity. Themandible is an accessible and durable bone that is very useful in this respect.Aim: To assess the efficacy of measuring the mandible ramus length in the identification of ageand sex in a group of Egyptians.Subjects and Methods: The length of the ramus of the mandible was measured in lateralcraniofacial scans of 213 individuals (99 males and 114 females) with an age range of 7-58 yearsusing cone-beam computerized tomography (CBCT).Results: Sexual dimorphism was not observed until age of 17 years in this sample. There wasnot found any significant differences in the length of the ramus of the mandible between malesand females in the age range of 7 to less than 17 years (P-value = 0.2495). There was a significantdifference between males and females for the mean length of the ramus in the age range of 17 to 58years (P-value < 0.0000). It predicts sex with an accuracy of 67%. There was a positive correlationbetween and (age) and loge (ramus length) (r=0.73, P-value < 0.0001 for females and r=0.85,P-value his or her mandible ramus length.Conclusion: The mandibular ramus length is valuable in age estimation and less valuable insex determination. Computerized tomography examination is a safe and an accurate procedurewith minimal radiation exposure, and provides valuable precise information regarding mandiblemeasurements.

Construct Validation of a Novel Hip Fracture Fixation Surgical Simulator.

A surgical simulation platform has been developed to simulate fluoroscopically guided surgical procedures by coupling computer modeling with a force-feedback device as a training tool for orthopaedic resident education in an effort to enhance motor skills and potentially minimize radiation exposure. The objective of this study was to determine whether the simulation platform can distinguish between novice and experienced practitioners of percutaneous pinning of hip fractures. Medical students, orthopaedic residents, orthopaedic trauma fellows, and attending surgeons completed in situ hip-pinning simulation that recorded performance measures related to surgical accuracy, time, and use of fluoroscopy. Linear regression models were used to compare the association between performance and practitioner experience. Notable associations were shown between performance and practitioner experience in 10 of the 15 overall measures (P < 0.05) and 9 of 11 surgical accuracy parameters (P < 0.05). This novel simulation platform can distinguish between novice and experienced practitioners and defines a performance curve for completion of simulated in situ hip pinning. This important first step lays the groundwork for subsequent validation studies, which will seek to demonstrate the efficacy of this simulator in improving clinical performance by trainees completing a sequence of skills-training modules.

LONG-LIVED RADIONUCLIDES IN THE PRODUCTION OF [18F]FLUOROCHOLINE FOR PET-DIAGNOSIS

In the present study the distribution of long-lived radionuclides between the drug product, recovered water [ 18O]H2 O and solid phase extraction cartridges was studied in [18F]fluorocholine production process. Isotopic composition for long-lived nuclides (half-lives = 10–312 days) was determined, the mechanisms of their formation and accumulation on cartridges are considered. It was shown that in the batches of pharmaceutical produced the content of long-lived nuclides is by 5 orders of magnitude lower than the limit value specified by the appropriate 07/2016:2793 European Pharmacopoeia article. The results obtained are of vital importance for optimization of the procedures for radioactive waste management in the production of [18F]fluorocholine using IBA Cyclone 18/9 HC cyclotron and, consequently, for minimization of radiation exposure of personnel.