Radiography Unit Research Articles

Image Quality Assessment of the Digital Radiography Units in Tabriz, Iran: A Phantom Study.

Creating a high-quality image with the low patient dose is one of the most important goals in medical X-ray imaging. In this study, the image quality parameters of the digital radiographic units in Tabriz city were considered and compared with the international protocols. The image quality parameters were measured at 11 high workload digital radiography (DR) imaging centers in Tabriz city, and the results were compared to DINN 6868/58 standards. All centers equipped with the direct DR units passed the spatial resolution, low contrast detectability, contrast dynamic range, and noise tests, while the computed radiography (CR) units only could pass the two last tests. The highest spatial resolution was observed 3.2 lp/mm in the DR unit while the lowest one was 1.8 lp/mm in the CR unit. The highest noise was measured to be 0.03 OD that was observed in the DR unit. The most difference between the nominal and measured peak kilovoltage and mAs was 3.1% and 6.8%, respectively. The entrance surface air kerma in all units was obtained <0.63 mGy. The measured half-value layer range was between 2.4 and 3.54 mmAl. The physical parameters of image quality such as spatial resolution, contrast, and noise are robustness quantitative parameters for the assessment of the image quality performance of the units. Therefore, measurement and control of these parameters using two-dimensional phantoms are very critical.

Comparison between Predicted and Measured X-Ray Output in Some Conventional Radiography Units

This study aims to investigate how accurate are TASMICS and TASMIP models in predicting the X-ray output of some Conventional Radiology X-ray units with high frequency generators. The X-ray output in microgray per milliampere seconds (μGy/mAs) at 100 cm from the X-ray tube was determined for selected high voltages and taking into account the total filtration. The X-ray output was then measured directly with the multi-purpose detectors (MPD), Raysafe X2. The maximum relative error between measured and predicted values was found to be equal to 20%. The maximum relative error between measured and predicted values obtained demonstrates the difficulty of accurately predicting the X-ray tube output using TASMICS and TASMIP models since they are based on fixed anode angles and different composition of the tungsten anode.

Comparison between predicted and measured x-ray output in some conventional radiography units

Comparison between predicted and measured x-ray output in some conventional radiography units

Performance of algorithms for tuberculosis active case finding in underserved high-prevalence settings in Cambodia: a cross-sectional study

ABSTRACTBackground: Most studies evaluate active case findings (ACF) for bacteriologically confirmed TB. Adapted diagnostic approaches are needed to identify cases with lower bacillary loads.Objectives: To assess the likelihood of diagnosing all forms of TB, including clinically diagnosed pulmonary and extra-pulmonary TB, using different ACF algorithms in Cambodia.Methods: Clients were stratified into ‘high-risk’ (presumptive TB plus TB contact, or history of TB, or presumptive HIV infection; n = 12,337) and ‘moderate-risk’ groups (presumptive TB; n = 28,804). Sputum samples were examined by sputum smear microscopy (SSM) or Xpert MTB/RIF (Xpert). Initially, chest X-ray using a mobile radiography unit was a follow-up test after a negative sputum examination [algorithms A (Xpert/X-ray) and B (SSM/X-ray)]. Subsequently, all clients received an X-ray [algorithms C (X-ray+Xpert) and D (Xray+SSM/Xpert)]. X-rays were interpreted on the spot.Results: Between 25 August 2014 and 31 March 2016, 2217 (5.4%) cases with all forms of TB cases were diagnosed among 41,141 adults. The majority of TB cases (1488; 67.1%) were diagnosed using X-ray. When X-rays were taken and interpreted the same day the sputum was collected, same-day diagnosis more than doubled. Overall, the number needed to test (NNT) to diagnose one case was 18.6 (95%CI:17.9–19.2). In the high-risk group the NNT was lower [algorithm D: NNT = 17.3(15.9–18.9)] compared with the ‘moderate-risk group’ [algorithm D: NNT = 20.8(19.6–22.2)]. In the high-risk group the NNT was lower when using Xpert as an initial test [algorithm A: NNT = 12.2(10.8–13.9) or algorithm C: NNT = 11.2(9.6–13.0)] compared with Xpert as a follow-up test [algorithm D: NNT = 17.3(15.9–18.9)].Conclusion: To diagnose all TB forms, X-ray should be part of the diagnostic algorithm. The combination of X-ray and Xpert testing for high-risk clients was the most effective ACF approach in this setting.

Characteristics of X-ray attenuation in nano-sized bismuth oxide/epoxy-polyvinyl alcohol (PVA) matrix composites

In this study, the X-ray attenuation by 2 mm matrix composites of epoxy-polyvinyl alcohol (PVA) filled with different percentages of bismuth oxide (Bi2O3) nanoparticles has been investigated using both mammography and general radiography units. The effect of adding thermosetting polymer (epoxy) over thermoplastic polymer (PVA) on the dispersion of n-Bi2O3 within the composite was explained using both secondary and backscattered scanning electron microscopy. The results indicated that the X-ray attenuation by the 2 mm n-Bi2O3/epoxy-PVA composites was increased with the increase of n-Bi2O3 loading while increasing the tube voltage from 23 to 100 kV. Moreover, X-ray was not detected by the composite filled with n-Bi2O3 more than 12 wt% at the tube voltage between 23 and 35 kV. This indicated that the matrix composite with 2 mm thickness filled with ≥ 12 wt% of n-Bi2O3 may be used as an X-ray-shielding material for the lower X-ray photon energies operated between 23 and 35 kV by the diagnostic X-ray machine.

Automated quality control assessment of clinical chest images.

The purpose of this study was to determine whether a proposed suite of objective image quality metrics for digital chest radiographs is useful for monitoring image quality in a clinical setting unique from the one where the metrics were developed. Seventeen gridless AP chest radiographs from a GE Optima portable digital radiography (DR) unit ("sub-standard" images; Group 2) and 17 digital PA chest radiographs ("standard-of-care" images; Group 1) and 15 gridless (non-routine) PA chest radiographs (images with a gross technical error; Group 3) from a Discovery DR unit were chosen for analysis. Group 2 images were acquired with a lower kVp (100 vs 125) and shorter source-to-image distance (127cm vs 183cm) and were expected to have lower quality than Group 1 images. Group 3 images were expected to have degraded contrast vs Group 1 images. Images were anonymized and securely transferred to the Duke University Clinical Imaging Physics Group for analysis using software described and validated previously. Individual image quality was reported in terms of lung gray level, lung detail, lung noise, rib-lung contrast, rib sharpness, mediastinum detail, mediastinum noise, mediastinum alignment, subdiaphragm-lung contrast, and subdiaphragm area. Metrics were compared across groups. To improve precision of means and confidence intervals for routine exams, an additional 66 PA images were acquired, processed, and pooled with Group 1. Three observer studies were conducted to assess whether humans were able to identify images classified by the algorithm as abnormal. Metrics agreed with published Quality Consistency Ranges with three exceptions: higher lung gray level, lower rib-lung contrast, and lower subdiaphragm-lung contrast. Higher (stored) bit depth (14 vs 12) accounted for higher lung gray level values in our images. Values were most internally consistent for Group 1. The most sensitive metric for distinguishing between groups was mediastinum noise, followed closely by lung noise. The least sensitive metrics were mediastinum detail and rib-lung contrast. The algorithm was more sensitive than human observers at detecting suboptimal diagnostic quality images. The software appears promising for objectively and automatically identifying suboptimal images in a clinical imaging operation. The results can be used to establish local quality consistency ranges and action limits per facility preferences.

P041] Upgrading the regular X-ray radio-graphic units with tomosynthesis

Purpose The purpose of the work. Implementation of tomosynthesis on standard X-ray equipment to accelerate its introduction into clinical practice under limited financial resources. Methods Cabin fluorograph, X-ray unit with 2 workplaces and remote tilting table with analog tomography modes were used in the work. 5 kW X-ray unit from C-arch on mobile platform was installed on the fluorograph. Instead of fluorographic chamber a dynamic digital receiver with 43 × 60 cm work field was installed on the cabin of the fluorograph. The X-ray units were equipped with high-frequency pulse-fluoro mode feeding device and dynamic digital receiver with 43 × 43 cm work field. Tomosynthesis modes with ±20° tomography angle were used in the studies. Exposure time was 4–6 s. Chest test phantom with X-ray target was studied. Results 200–400 slices of study object were received in tomosynthesis mode. Resolution in image plane amounted to 2.1 × 1.6 lp/mm and the effective thickness of tomographic slices was 2–8 mm. The total exposure in chest tomosynthesis did not exceed 20.0 mAs that is 3–6 times more than with the standard chest radiography and 5–10 times less than with the standard computer tomography. According to experts, the obtained chest phantom slices presented details that are poorly visible on X-ray images. Tomosynthesis mode compared to X-ray enabled to measure more accurately the geometric dimensions of the studied objects, as well as to assess the relative density of tissue in each slice. The probability increased of receiving correct diagnosis without referring the patient to CT or MRI study. Conclusions Using standard X-ray equipment tilting devices allows reducing by not less than 30% the expenses connected with introduction into clinical practice of tomosynthesis, which substantially expands the possibilities of roentgen diagnostics.

Effect of nanofibrous porosity on the X-ray attenuation properties of electrospun n-Bi2O3/epoxy–polyvinyl alcohol (PVA) nanofiber mats

In this study, the X-ray attenuation properties of electrospun nanoparticles (n)-Bi2O3/epoxy–polyvinyl alcohol (PVA) nanofiber mats with different filler loadings of n-Bi2O3 were compared as a function of X-ray tube voltages (40–100 kV) using a general radiography unit. It was found that the X-ray attenuation by the electrospun n-Bi2O3/epoxy–PVA nanofiber mats increased with the increment of filler loading except for the nanofiber mat with 12 wt% of n-Bi2O3 filler. This indicated that the nanofiber mat presents the lowest X-ray attenuation properties compared to the others with another filler loading. The result was explained by cross-sectional scanning electron microscopy (SEM) image, which revealed that the 12 wt% of electrospun n-Bi2O3/epoxy–PVA nanofiber mat has the highest amount of porosity compared to the other samples.

Digital dental radiology in Belgium: a nationwide survey.

The aim of this study is to analyse the use of digital dental radiology in Belgium, by focussing on the use of extraoral and intraoral radiographic techniques, digitalisation and image communication. A nationwide survey has been performed amongst Belgian general dentists and dental specialists. Questionnaires were distributed digitally via mailings lists and manually on multiple refresher courses and congresses throughout the country. The overall response rate was 30%. Overall, 94% of the respondents had access to an intraoral radiographic unit, 76% had access to a panoramic unit, 21% has an attached cephalometric arm. One in five Belgian dentists also seem to have direct access to a cone beamCT. 90% of all intraoral radiography unit worked with digital detectors, while this was 91% for panoramic units (with or without cephalometrics). In 70% of the cases, general dental practitioners with a digital intraoral unit used a storage phosphor plate while in 30% of the cases they used sensor technology (charge-coupleddevice or complementarymetal-oxide-semiconductor). The most common method for professional image transfer appeared to be email. Finally, 16% of all respondents used a calibrated monitor for image analysis. The survey indicates that 90% of the respondents, Belgian dentists, make use of digital image techniques. For sharing images, generaldental practitioners mainly use methods such as printout and e-mail. The usage of calibrated monitors, however, is not well established yet.

Electronic collimation of radiographic images: does it comprise an overexposure risk?

To investigate whether electronic collimation software, which is available in all digital X-ray systems, may comprise an overexposure risk. In the context of surveys on Diagnostic Reference Levels carried out in two radiographic facilities, along with data on exposure factors, the radiographic field sizes were also recorded. In one facility (Unit A), a wireless flat panel detector is used with a conventional X-ray unit, while in the other, a fully digital system is installed (Unit B). The electronically collimated image sizes were compared with the original radiation field sizes. The differences between these two systems concerning the field sizes and the mode of electronic collimation utilization were investigated. In Unit A, manual electronic collimation was extensively used and cases where the radiation field size was up to three times larger than that electronically collimated, were identified. On the contrary, in Unit B radiation fields were smaller and electronic collimation was automatic. When electronic collimation is used in manual mode instead of proper pre-exposure collimation, then it does comprise an overexposure risk. The risk is larger in radiographic units where the field size is not automatically selected according to the examination protocol and no interlocks against oversized collimation settings exist. Advances in knowledge: When radiologists review masked images to make the diagnosis, possible suboptimal X-ray field collimation practices may go unnoticed for long. Therefore, radiologists and medical physicists should periodically survey the original images to determine the actual radiation field sizes used for each radiographic examination type.

Mobile miniature X-ray evaluation and pneumoconiosis: the role of the Clinica del Lavoro in Milan (1941-1948)

«Mobile miniature X-ray evaluation and pneumoconiosis: the role of the Clinica del Lavoro in Milan (1941-1948)». Since the end of the 19th century, X-rays have been used to detect lung diseases. In Italy, 207,096 miniature chest radiographs were taken from 1941 to 1948. Traditional radiographs gave better results, but miniature chest radiographs were useful for screening. Indeed, the development of mobile miniature chest radiography units resulted in an improvement in mass X-rays screening for the detection of penumoconiosis. These mobile miniature units were mounted on a bus chassis, a solution that allowed to easily reach workers. The authors analyze some models of X-ray wagon units used by the “Clinica del Lavoro” in Milan in the 1950s. From the point of view of medical museology, the preservation of these devices requires appropriate spaces.

Evaluation of the Quality Control Program for Diagnostic Radiography and Fluoroscopy Devices in Syria during 2005-2013

Introduction: Extensive use of diagnostic radiology is the largest contributor to total population radiation doses. Thus, appropriate equipment and safe practice are necessary for good-quality images with optimal doses. This study aimed to perform quality control (QC) audit for radiography and fluoroscopy devices owned by private sector in Syria (2005-2013) to verify compliance of performance of X-ray machines with the regulatory requirements stipulated by the national regulatory body. Materials and Methods: In this study, QC audit included 487 X-ray diagnostic machines, (363 radiography and 124 fluoroscopy devices), installed in 306 medical diagnostic radiology centers in 14 provinces in Syria. We employed an X-ray beam analyzer device (NERO model 8000, Victoreen, USA), which was tested and calibrated at the National Secondary Standard Dosimetry Laboratory traceable to the IAEA Network of Secondary Standard Dosimetry Laboratories. Standard QC tool kits were used to evaluate tube and generator of the X-ray machines, which constituted potential (kVp), timer accuracy, radiation output consistency, tube filtration, small and large focal spot sizes, X-ray beam collimation and alignment, as well as high- and low-resolution and entrance surface dose in fluoroscopy. Results: According to our results, most of the assessed operating parameters were in compliance with the standards stipulated by the National Regulatory Authority. In cases of noncompliance for the assessed parameters, maximum value (28.77%) pertained to accuracy of kVp calibration for radiography units, while the lowest value (2.42%) belonged to entrance surface dose in fluoroscopy systems. Conclusion: Effective QC program in diagnostic radiology leads to obtaining information regarding quality of radiology devices used for medical diagnosis and minimizing the doses received by patients and medical personnel. The findings of this QC program, as the main part of QA program, illustrated that most of the considered diagnostic X-ray devices had acceptable performance and few of them need to be recalibrated for some parameters.

Lung Field Segmentation in Chest Radiographs From Boundary Maps by a Structured Edge Detector

Lung field segmentation in chest radiographs (CXRs) is an essential preprocessing step in automatically analyzing such images. We present a method for lung field segmentation that is built on a high-quality boundary map detected by an efficient modern boundary detector, namely a structured edge detector (SED). A SED is trained beforehand to detect lung boundaries in CXRs with manually outlined lung fields. Then, an ultrametric contour map (UCM) is transformed from the masked and marked boundary map. Finally, the contours with the highest confidence level in the UCM are extracted as lung contours. Our method is evaluated using the public Japanese Society of Radiological Technology database of scanned films. The average Jaccard index of our method is 95.2%, which is comparable with those of other state-of-the-art methods (95.4%). The computation time of our method is less than 0.1 s for a CXR when executed on an ordinary laptop. Our method is also validated on CXRs acquired with different digital radiography units. The results demonstrate the generalization of the trained SED model and the usefulness of our method.

RADIOGRAPHY IN THE FIELD: ASSESSING A LIGHTWEIGHT, HANDHELD, BATTERY-POWERED DENTISTRY UNIT FOR FIELD DIAGNOSTIC APPLICATIONS.

Radiography units are not used commonly in wildlife medicine field settings, primarily because of their weight and requirement for a power supply. In this study, a portable, battery-powered, and lightweight radiography unit, originally developed for dentistry, was assessed for its potential field applications. Radiographs of various animal species (ranging in weight from 14 g to 1,000 kg) were imaged using varying source image distance (SID) and exposure time. The quality of these images was evaluated for their resolution, image noise, and motion blur. When required, image resolutions were further enhanced using computed radiography postprocessing. Other parameters evaluated were the freehand use of the device, its battery durability, the maximum obtainable image size, and multiple use of a single computed radiography cassette. Using an SID of 60 cm, radiographs delivered adequate image quality. The quality, however, was found deteriorated in images of larger animals (>50 kg) or thicker tissues (>15 cm). The use of a tripod proved unnecessary in most cases, and its exclusion greatly facilitated equipment handling. Under field conditions, the battery was depleted after a total running time of 1.6 hr or 36 radiographs. The maximum size of a radiographic image reached a diameter of 40 cm, and radiation shielding allowed the multiple use of a single computed radiography cassette. Taken together, the radiography unit evaluated in this study presented a balanced compromise between portability and radiograph quality for field use. However, the unit image resolution cannot replace those of the fixed standard radiography units commonly used in veterinary medicine.

Changes in taste sensation of sour, salty, sweet, bitter, umami, and spicy, as well as levels of malondialdehyde serum in radiographers

Background: Radiation used for any purpose certainly contains potential danger to humans. Radiographers are given a task, authority, and responsibility by the competent authority to conduct radiography and imaging in health services unit. Some researcheson the effects of radiation on cancer patients show that radiation can cause an increase in bitterness and metal taste [in cancer patients] leading to discomfort in the oral cavity. In body, free radicals then can cause lipid peroxidation process. Lipid peroxidation is an oxidative destruction of polyunsaturated fatty acid producing malondialdehyde (MDA). Purpose: This study aimed to determine the effects of radiation on changes in the taste sensation of sour, salty, sweet, bitter, umami, and spicy as well as the levels of MDA serum in radiographers. Method: This study was an observational laboratory research using post- test control design. Samples were selected using simple random sampling technique. The samples were seven radiographers who have been working for five years in the laboratory and radiographic units in Surabaya. Result: Based on the results of statistical tests, it showed that there were no differences in the sensitivity of all tastes between the groups tested. Moreover, the results also depicted considerable value for the sour taste was 0.550, the saltiness was 0.775, the sweetness was 0.294, the bitter taste was 0.065, the umami taste was 0.705, and the spicy taste was 0.319 (p&gt;0.05). However, the dramatic increase was higlighted in levels of MDA serum with a significant value of 0.065 (p&gt;0.005). Conclusion. There were no changes in the sensitivity of sour, salty, sweet, bitter, umami, and spicy tastes, but there was a significant increased in level of MDA serum in the radiographers compared to the control group.

Accuracy of Ultrasound for Diagnosis of Femur Bone Fractures in Traumatic Patients

Objective: to evaluate the safety and applicability of the ultrasound diagnostic procedure in comparison to Radiography for detecting femur bone fractures in lower limbs. Methods: We assessed 30 injured patients with suspected femur bones fracture that had presented to the ED. The patients were older than 18 years that transferred to the resuscitation room of the ED. Then, bedside ultrasound was performed for them. After the clinical conditions became stable, the patients were referred to the radiography unit for imaging. The findings are separately and blindly assessed, then would be compared with together. Sensitivity, specificity, the positive and negative predictive values and P-value were measured to appraisal the accuracy of ultrasound as compared with radiography (gold standard). Results: The results of sensitivity, specificity, PPV and NPV for bones fracture of femur with linear array transducer of portable sonography and P-value not significant statistically. Sensitivity, positive predictive value and P-value for diagnosis of femur shaft fractures with deep array transducer of ultrasound were 90%, 47.3% and 0.0006 (<0.05), respectively. Conclusion: In our study, evidences showed ultrasound is accurate equally to radiography for fractures diagnosis of shaft of femur in lower limb with deep array transducer of ultrasound in adults.

A quasi-experimental study to determine the effects of a multifaceted educational intervention on hand hygiene compliance in a radiography unit.

BackgroundWhilst numerous studies have investigated nurses’ compliance with hand hygiene and use of alcohol-based hand rub (ABHR), limited attention has been paid to these issues in allied health staff. Reports have linked infections to breaches in infection control in the radiography unit (RU). With advances in medical imaging, a higher proportion of patients come into contact with RU staff increasing the need for good hand hygiene compliance. This study aimed to evaluate effectiveness on compliance of an intervention to improve awareness of hand hygiene in the RU of a district hospital.MethodsA quasi-experimental study design including questionnaires assessing knowledge and attitudes of hand hygiene and direct observation of participants was used to evaluate an educational programme on hand hygiene of the RU of a large district hospital. All healthcare workers (HCW), comprising 76 radiographers, 17 nurses, and nine healthcare assistants (HCA), agreed to participate in the study. Of these, 85 completed the initial and 76 the post-test anonymous questionnaire. The hand hygiene compliance of all 102 HCW was observed over a 3-week period prior to and after the intervention. The 2-month intervention consisted of talks on hand hygiene and benefits of ABHR, provision of visual aids, wall-mounted ABHR dispensers, and personal bottles of ABHR.ResultsBefore the intervention, overall hand hygiene compliance was low (28.9 %). Post-intervention, compliance with hand hygiene increased to 51.4 %. This improvement was significant for radiographers and HCA. Additionally, knowledge and attitudes improved in particular, understanding that ABHR can largely replace handwashing and there is a need to perform hand hygiene after environmental contact. The increased use of ABHR allowed HCW to feel they had enough time to perform hand hygiene.ConclusionsThe educational intervention led to increased awareness of hand hygiene opportunities and better acceptance of ABHR use. The reduced time needed to perform hand rubbing and improved access to dispensers resulted in fewer missed opportunities. Although radiographers and other allied HCW make frequent contact with patients, these may be mistakenly construed as irrelevant with respect to healthcare associated infections. Stronger emphasis on hand hygiene compliance of these staff may help reduce infection risk.

SU‐F‐I‐79: Validation of a Monte Carlo Radiographic Simulation

Purpose:To validate a radiographic simulation in order to estimate patient dose due to clinically‐used radiography protocols.Methods:A Monte Carlo simulation was created to simulate a radiographic x‐ray beam using GEANT4. Initial validation was performed according to a portion of TG 195. Computational NURBS‐based phantoms were used simulate patients of varying ages and sizes. The deposited energy in the phantom is output by the simulation. The exposure in air from a clinically used radiography unit was measured at 100 cm for various tube potentials. 10 million photons were simulated with 1 cubic centimeter of air located 100 cm from the source, and the total absorbed dose was noted. The normalization factor was determined by taking a ratio of the measured dose in air to the simulated dose in air. Dose to individual voxels is calculated using the energy deposition map along with the voxelized and segmented phantom and the normalization factor. Finally, the effective dose is calculated using the ICRP methodology and tissue weighting factors.Results:This radiography simulation allows for the calculation and visualization of the energy deposition map within a voxelized phantom. The ratio of exposure, measured using an ionization chamber, to air in the simulation was determined. Since the simulation output is calibrated to match the exposure of a given clinical radiographic x‐ray tube, the dose map may be visualized. This will also allow for absorbed dose estimation in specific organs or tissues as well as a whole body effective dose estimation.Conclusion:This work indicates that our Monte Carlo simulation may be used to estimate the radiation dose from clinical radiographic protocols. This will allow for an estimate of radiographic dose from various examinations without the use of traditional methods such as thermoluminescent dosimeters and body phantoms.

SU‐F‐I‐78: Design of Diagnostic Multileaf Collimator Based On the Monte Carlo Simulation for Dose Reduction of Diagnostic Radiography

Purpose:A diagnostics Multileaf Collimator (MLC) was designed for diagnostic radiography dose reduction. Monte Carlo simulation was used to evaluate efficiency of shielding material for producing leaves of Multileaf collimator.Material &amp; Methods:The general radiography unit (Rex‐650R, Listem, Korea) was modeling with Monte Carlo simulation (MCNPX, LANL, USA) and we used SRS‐78 program to calculate the energy spectrum of tube voltage (80, 100, 120 kVp). The shielding materials was SKD 11 alloy tool steel that is composed of 1.6% carbon(C), 0.4% silicon (Si), 0.6% manganese (Mn), 5% chromium (Cr), 1% molybdenum (Mo), and vanadium (V). The density of it was 7.89 g/m3. We simulated leafs diagnostic MLC using SKD 11 with general radiography unit. We calculated efficiency of diagnostic MLC using tally6 card of MCNPX depending on energy.Results:The diagnostic MLC consisted of 25 individual metal shielding leaves on both sides, with dimensions of 10 × 0.5 × 0.5 cm3. The leaves of MLC were controlled by motors positioned on both sides of the MLC. According to energy (tube voltage), the shielding efficiency of MLC in Monte Carlo simulation was 99% (80 kVp), 96% (100 kVp) and 93% (120 kVp).Conclusion:We certified efficiency of diagnostic MLC fabricated from SKD11 alloy tool steel. Based on the results, the diagnostic MLC was designed. We will make the diagnostic MLC for dose reduction of diagnostic radiography.

TU-FG-209-07: Medical Physics 1.0 Versus Medical Physics 2.0: A Case Study

Purpose: To illustrate how performance analytics can identify performance decrement in digital radiography systems. Methods: Subsequent to a radiologist's image quality complaint, four different advanced methods contributed to root cause analysis. Our system was a GE Revolution XQi digital radiography unit. Initially, we reviewed weekly GE Quality Assurance Procedures (QAP) results in a database dating from 2001. Next, we evaluated objective image quality metrics of individual PA Chest radiographs acquired. These images were anonymized, securely transferred, and analyzed by the Duke University Clinical Imaging Physics Group with software previously described1 and validated2. Third, we compared the exposure-dependent SNR2 (NEQ) of the unit with previously established confidence limits3. Finally, we explored our service database to reveal events that might affect detector performance. Results: QAP reported a decrease in CNR reflected in a significant increase in lung noise(Ln), mediastinum noise(Mn), and subdiaphragm-lung contrast(Slc) with a significant decrease in lung grey level(Lgl) after detector replacement. Most change occurred during week 1, before the QAP indicated one-half the ultimate decrease in CNR. After detector recalibration, QAP CNR improved, but was not restored to previous levels. Lgl and Slc were no longer significantly different from before, however Ln and Mn remained significantly different. Exposure-dependent SNR2 show the detector to be operating within limits in October 2006 but subsequently became miscalibrated sometime before acquisition of the 2011–2014 data. Service records revealed catastrophic failure of the Image Detection Controller that contained the 2007 calibration. Traditional metrics did not indicate that the system was performing outside of normal limits. Conclusion: Performance analytics are powerful tools whose proper application could allow early intervention in degraded system performance. The image-quality metrics appear to be highly sensitive to system performance and are reported with every acquisition rather than at arbitrary intervals. Confidence intervals may require customization for individual systems or detectors.