Radiographic Film Research Articles

Preclinical Intraoperative FLASH Radiotherapy

Intraoperative radiation therapy (IORT) is a method of delivering high radiation doses to an internal target with low dose to adjacent organs. Most organs at risk can often be moved out of the radiation field, so dose is usually limited by in-field vascular and/or nerve structures. It is known that ultra-high (FLASH) dose rate (>40 Gy/s) radiation reduces normal tissue toxicity compared to conventional, while preserving tumor control. We hypothesize that FLASH radiation can increase the dose tolerance of vascular and nerve structures, thus permitting for dose escalation in IORT. Here, we present a novel platform using orthovoltage x-rays to study FLASH effects in preclinical IORT. The experimental setup and dosimetry of the system have been established for FLASH irradiation of the abdominal aorta in rats to investigate dose tolerance. A 150 kVp rotating anode x-ray source with a 75-kW generator was used to deliver FLASH and conventional irradiation. A 3D printed immobilization platform was designed to reproducibly place a surgically exposed rat abdominal aorta at 55mm SSD. A 3-mm thick lead collimator with a 10mm x 10mm aperture was placed into a flange adapter, which docks into the immobilization platform. Phantom and in vivo dosimetry were performed using both calibrated radiographic film and thermoluminescent dosimeters (TLD). Anesthetized 2-month-old Wistar rats underwent laparotomy to expose the abdomen for irradiation. A 10x12x1 mm3 tungsten plate was placed under the aorta to reduce spinal cord dose. Animals were then docked into the irradiator using the immobilization platform. Radiation dose in the range of 20 - 50 Gy were delivered to the abdominal aorta at FLASH and conventional dose-rates. Following treatment, animals undergo MR angiography every two months for 6 months, at which a histological evaluation of aorta wall will be performed. The FLASH dose rate measured at the aorta wall in a rat carcass was 49.7 ± 1.2 Gy/s distal to the collimator. Dose measurements between the films and TLDs showed an agreement within ±3%. Positional uncertainty mainly depends on the visual localization of the aorta on the collimator window, which is verified before irradiation. Vertical uncertainty is less than 1 mm, which is important given the rapid dose fall off of the system. Eight animals went successfully through the procedure, are healthy and currently being follow up with MR angiography. More animals are being treated for meaningful statistical results. MR angiography and IORT are performed on different days to avoid longer times under anesthesia, which initially resulted on mortality. Results of the MR angiography and histological analysis will be presented. The proposed platform has been successfully utilized for precision setup for FLASH IORT in a preclinical laboratory setting. Evaluation of FLASH effects in IORT setup will be an important step in the potential translation of FLASH IORT, where only one high-dose fraction can be delivered.

Evaluation of Patient-Specific Quality Control (QC) for Markerless Dynamic Tumor Tracking (MDTT) Deliveries

To report on the patient-specific QC for MDTT for liver and lung tumors treated using the dome-of-liver/diaphragm as a surrogate for the target position and compare to the QC of conventional fiducial-based tracking. Vero4DRT is a linear accelerator that has a gimbal-mounted waveguide and collimation system allowing the radiation beam to perform dynamic tumor tracking based on a patient's respiratory motion. A correlation model is built between an external IR marker placed on the chest and an internal structure, which may be implanted fiducial surrogates or in the case of MDTT, an anatomic landmark. During treatment an orthogonal kV image pair is taken every second. The auto detected internal structure position versus the predicted position is recorded in treatment log files. Five IMRT tracking plans were delivered to two commercial motion phantoms with in-house additions for patient-specific tracking QC. For point dose measurements, a 0.6cc farmer chamber was placed inside the dynamic tracking phantom which contains fiducials for fiducial-based tracking delivery and an anatomic landmark for MDTT. For 2D dose distribution measurements, a radiographic film insert for the Quasar Respiratory Motion Phantom was constructed. The phantom contains both fiducials and has a liver-dome shape at one end to facilitate MDTT. Both motion platforms were interfaced with software that enabled patient-specific respiratory motion traces acquired during a 4DCT scan. Each plan was delivered three times on each phantom: 1) in static mode, 2) during fiducial-based tracking, and 3) during MDTT. Chamber measurements taken during static and tracked delivery were compared to the average chamber dose from the treatment planning software (TPS). Film distributions measured during tracked deliveries were compared to the static film distribution using gamma analysis with FILMQA PRO software. Finally, dynamic tracking treatment statistics, extracted from log files, were compared between fiducial and markerless tracking deliveries. All chamber measurements resulted in dose differences <2.5% compared with the TPS. Dose differences between fiducial-based and MDTT were 0.26% on average (range 0.03-0.62%). For film dose map analysis, gamma pass rates were >95% for all plans for all tracking methods. The average gamma pass rate for 3%/3mm was 99.4% (fiducial-based) vs 98.4% (markerless). For 2%/2mm, the average gamma pass rate was 96.4% (fiducial-based tracking) vs 95.6% (MDTT). Dynamic treatment statistics from logs files reported an average 3D absolute deviation from predicted position of 0.52mm (±0.24) for fiducial tracking and 1.19mm (±0.50) for MDTT. Both fiducial-based and MDTT plans meet passing criteria for patient-specific QC. 3D absolute deviation of detected versus predicted position are larger for MDTT compared to fiducial tracking, however no significant impact on dose delivery was measured.

Characterization of Radiographic and Molecular Changes in Mouse Brain after FLASH Irradiation

Despite refinements in treatment platforms such as incorporation of high-resolution imaging and real time motion tracking, the amount of radiation dose delivered safely to a particular tissue type is limited by both tissue intrinsic and extrinsic factors. FLASH radiotherapy (RT), delivery of relatively high radiation dose at dose rates several orders of magnitude higher than that of conventional (CONV) dose-rates, may change that paradigm due to normal tissue sparing characteristics of FLASH RT. Our Radiation Oncology Physics division developed a novel FLASH kV x-ray cabinet system for preclinical laboratory research. Here we utilize this technology to establish optimal radiation parameters for FLASH effect in brain tissue of a murine model. A range of total radiation dose and dose rates that are considered to be within the window for FLASH effect are being investigated. We have identified several measurable and clinically meaningful toxicity outcomes, including radiation necrosis and blood brain barrier integrity, to assess FLASH effects in brain tissue. A high-capacity rotating anode x-ray tube was implemented for FLASH irradiation, operating at 150 kVp with 0.025 mm Cu added filtration. A custom 3D printed immobilization tool was designed to reproducibly position animals for stereotactic irradiation of the brain. Dose and dose rate measurements were performed with calibrated radiographic film in kV solid water. Conventional dose rate irradiations were delivered using a standard laboratory irradiator (SARRP) operating at the same kVp and filtration. The depth-dose gradients in solid water were compared between the irradiators. Healthy 8-week-old C57BL6J mice were then irradiated with graded doses of FLASH and CONV x-rays (10- 60 Gy) using a single 1-cm wide AP field. Dose was prescribed to the center of the brain, at a depth of 3.25 mm. RT-induced necrosis is being monitored by serial biweekly MR imaging using a 7-T preclinical MRI machine. Histopathological changes will be assessed through H&E staining of harvested brain at 3-months post-irradiation (n = 5 per arm). FITC-Dextran infusion will be performed prior to necropsy to assess blood-brain barrier integrity. Animal setup for stereotactic FLASH brain irradiation was reproducible to within 0.5mm. Measured dose rates were 75.6 Gy/s for FLASH and 3.8 Gy/min for conventional irradiations. At 5-mm depth in solid water, the PDDs agreed to within 4% between SARRP and FLASH Irradiator. Biweekly T1 post and T2 weighted image acquisition is currently underway. Histology and FITC-Dextran data will be presented when available. We have successfully designed a high-precision platform to study x-ray FLASH effects in mice brain model. Evaluation of dose window for brain FLASH effect and molecular mechanisms of this phenomenon is an important step in the potential translation of FLASH RT for brain irradiation.

241 ‘Please consider bone assessment’: improving the identification and management of Vertebral Fractures by a ‘Fracture Liaison Service’

Abstract Background Osteoporotic fractures are a major public health problem due to an ageing population causing profound disability and reduced quality of life. Vertebral Fractures (VFs) are the second most common osteoporotic fracture with nearly 1 in 4 women having one in their lifetime. Furthermore, a VF is a significant warning sign for another fracture in the following year—known as ‘imminent fracture risk’. Despite this early opportunity for clinical intervention with bone protective medication, VFs are frequently under-diagnosed and under-treated. This observational study aimed to look at the point prevalence of VFs picked up on radiology reports and compare with those identified by the ‘Fracture Liaison Service’ (FLS). Methods The PACs office ran a search for all MRI spine, CT-TAP and a plain radiographic film reports from January 2021 until April 2023 with the terms ‘vertebrae’ and ‘compression’ in the text. Inclusion criteria was all patients &amp;gt;65 without major trauma with a radiologist defined osteoporotic VF. Using excel, we cross-referenced the proportion of these already know to the FLS. Results There were 338 osteoporotic VFs diagnosed on radiological imaging between 2021 &amp; 2023. Of these, 101 had been identified by the FLS. The median age was 77 years old. There were 228 (67.2%) females and 111 (32.8%) males. Conclusion This study helped to highlight that over 67.2% of the osteoporotic VFs are not being identified by the FLS. Therefore, is it assumed that timely intervention and management of their imminent fracture risk may not have been undertaken. This data is being used to drive a quality improvement project with the radiology department where any VF in women &amp;gt;70 will be reported to include—‘please consider bone assessment’.

Salivary Total Protein and Alkaline Phosphatase Activity as Biomarkers for Skeletal Maturity and Growth Prediction in Healthy Children: An In Vivo Study.

Skeletal maturity assessment involves radiographic analysis and visual inspection of developing bone and their initial appearance or sequential ossification and related changes in size and shape along with the expression of various biomarkers in body fluids. To investigate the correlation of biomarkers such as salivary alkaline phosphatase (S-ALP) and salivary total protein (STP) with skeletal maturity assessment and growth prediction in growing children. A total of 8-15-year-old 150 healthy children were divided into five groups depending upon radiographic stage maturity of the middle phalanx of the left hand's third finger according to the Hagg and Taranger method. Radiographs were taken using intraoral periapical (IOPA) radiographic films. Salivary alkaline phosphatase (S-ALP) activity in the MP3 G group was significantly higher than MP3 F group and MP3 I group. Total protein levels in MP3 F were significantly lower than in MP3 G. The mean value of S-ALP (33541.45 IU/L) and that of STP (2.77 mg/mL) was observed to be highest in the MP3 G group (G3) group. Salivary total protein (STP) and S-ALP may be used as an additional diagnostic tool to assess skeletal maturation and optimize growth prediction during myofunctional orthodontic treatment. Skeletal maturity assessment plays a significant role in orthodontic diagnosis, treatment planning, and stability of orthodontic treatment. Radiographic parameters involve radiographic exposure; hence in this study noninvasive biomarkers such as S-ALP and STP have been evaluated for skeletal maturity assessment and growth prediction. Abhangi KK, Choudhari SR, Butala PB, et al. Salivary Total Protein and Alkaline Phosphatase Activity as Biomarkers for Skeletal Maturity and Growth Prediction in Healthy Children: An In Vivo Study. Int J Clin Pediatr Dent 2023;16(4):603-607.

261 Bilateral Femoral Neck Stress Fractures in an Active Adolescent Female: A Case Report

Abstract Bilateral femoral neck stress fractures are uncommon injuries in adolescents. We present such a case in a 15-year-old athletic female with no preceding trauma or underlying metabolic bone abnormality. The patient presented to Accident and Emergency with a three-week history of left buttock and lateral thigh pain and one-week history of right lateral thigh pain. The pain developed during physical activity and was relieved upon rest. Activities included running, dancing, and attendance at a six-week cadet marching course. Simple analgesia did not alleviate the pain. History revealed low caloric intake and previous secondary amenorrhea. The patient was previously managed by the General Practitioner and physiotherapist for suspected atypical sciatica. Physical examination showed a minimally antalgic gait and pain on palpation of the left groin. Both hips had full range of motion. Bone profile was normal. Radiographic films were initially interpreted as normal, however, formal reporting revealed sclerotic appearances to both femoral necks and a subtle break in the left femoral neck cortex. MRI confirmed the diagnosis of a complete displaced left femoral neck fracture and incomplete right inferomedial femoral neck fracture. Trace bilateral hip joint effusions were noted. The patient underwent bilateral fixation with cannulated screws. One-month post-operative, she engaged in walking and swimming without pain. Radiographic appearances were satisfactory. Early radiographic changes associated with stress fractures are subtle. This case highlights the importance of prompt formal radiological reporting and the early use of MRI as a diagnostic tool, particularly in patients with risk factors.

387 A Multidisciplinary Approach to the Sequelae of Dental Trauma in a Child: A Radicular Cyst

Abstract Background A radicular cyst is an inflammatory cyst of odontogenic nature, formed by cells of Malassez in the periodontal ligament, which are stimulated and proliferate, following insults such as dental trauma. First stage treatment is commonly orthograde root canal treatment (RCT), followed by apicectomy or extraction and enucleation of the lesion +/- bone grafting and replacement tooth. Presenting problem This case illustrates the sequelae of a repeated dental trauma to a LR1 in a child, which was endodontically treated and obturated with Mineral Trioxide Aggregate (MTA). After a second dental trauma, a painful intra-oral swelling developed with mobility and tenderness of adjacent teeth. The swelling increased after extraction of the LR1, leading to enucleation by the Oral and Maxillofacial Surgery Surgeon (OMFS). Investigations Plain radiographic films, cone beam CT (CBCT) imaging revealing a radiolucent area extending from LR3 to LL3, 2 x 1.1 x 1.9cm, with buccal perforation and thinning of the lingual cortex. Clinical management Across a 6-year period restoration and orthograde RCT was completed LR1. A second dental trauma 4 years later necessitated extraction of LR1. Subsequent acute swelling and pain lead to further radiological assessment which was consistent with a giant cell lesion. Following enucleation, histopathology confirmed a radicular cyst, with pulse granuloma and reactive changes. Bony infill was noted and the LR1 was replaced with a resin-retained bridge. Discussion This case aims to raise awareness of the sequelae of dental trauma in children and the multidisciplinary approach to their care.

344 Are Rings Removed in Hand Trauma? a Closed Loop Audit

Abstract Aim Constriction injury secondary to jewellery can be a serious consequence of hand injury. National guidelines therefore advise that all jewellery is removed as the initial step in managing hand trauma, prior to any imaging. This audit evaluated adherence to this guideline, and to assess the effect of a patient and clinician centred intervention. Method All patients who had plain film radiographs of the hand performed by the emergency department of a major trauma centre were assessed for radiopaque jewellery in situ. Further data were then collected including demographics, mechanism of injury, and resultant surgical procedures. A 4-month baseline audit was conducted in 2021. Interventions were implemented, including patient- and clinician-facing posters. A post intervention cycle was completed over 5 months in 2022. Results 7563 individual patients presenting with hand trauma were included in the audit across both cycles. In 2021, 115 of 3542 patients had jewellery identified in situ. In 2022, 107 of 4021 patients had jewellery identified, an improvement of 18.1%. General demographics of these patients remained broadly similar across both cycles. The patients were predominantly female (64%) and the jewellery seen most frequently was a metal ring, often on the left ring finger (84%). Injury types included lacerations, fractures, and soft tissue injuries. 1 in 4 of these patients required a further surgical procedure from the injury. Conclusions This audit demonstrated the success of both patient and clinician facing interventions to improve the rate of removal of jewellery as the first stage of hand trauma.

Inter-Examiner Agreement of the National Upper Cervical Chiropractic Association Analysis of the Atlas Subluxation Complex in a 3-View Upper Cervical Radiographic Series

ObjectiveThe purpose of this study was to measure the inter-examiner agreement between radiograph markings of 2 National Upper Cervical Chiropractic Association board-certified chiropractors. MethodsTwo chiropractic examiners who had standardized training marked and analyzed 254 conventional orthogonal radiographic film sets. The level of agreement and potential biases in their measurements were assessed using intraclass correlation coefficients for absolute agreement and Bland-Altman plot analyses. ResultsThere was 96.1% agreement between the examiners in the measurements of the side of atlas laterality and 94.5% for atlas rotation. The intraclass correlation coefficient was 0.95 (95% CI, 0.93-0.96) for atlas laterality and 0.92 (95% CI, 0.89-0.94) for atlas rotation. The mean difference in the measurement between the 2 examiners was −0.11, P = .12 for atlas laterality and 0.05, P = .55 for atlas rotation. Neither atlas laterality nor atlas rotation measurements were significantly different from zero. Bland-Altman plots were not suggestive of any proportional biases in the 2 measurements. ConclusionResults of this study show almost perfect agreement between 2 trained chiropractic examiners, with no apparent proportional bias in the analysis of conventional orthogonal radiographic film sets.

Radiographic film waste management and recovery

Health facilities in Romania generate hundreds of thousands of tons of medical waste (hazardous and non-hazardous) annually. It is therefore necessary to apply a rigorous management of this waste, in compliance with applicable regulations, especially in the case of waste with a high potential for harmfulness. In the context of the global PANDEMIC of COVID 19, the amount of radiographic films generated has increased, using the classic variant when the moderns investigative devices was no longer available. The legislation requires hospitals and clinics to follow certain rules regarding the management of X-rays films. These are considered private information and must be managed according to the legislation, but silver and other chemicals in the film are toxic to the environment when are disposed uncontrolled. Recycling companies prefer to recover silver from effluents used to obtain classical radiography, recovery that is done by electrolysis and does not require large investments.The paper presents a relatively simple technology of recycling the radiographic films starting from laboratory studies, by leaching them in sodium hydroxide solution and the implications from the point of view of managing such activities.

Investigation of Extraoral Dental Radiography Examination Rejections at a Dental and Oral Hospital in Semarang, Indonesia

Background : Extraoral radiography techniques, such as panoramic radiography and cephalometric radiography, are used to obtain an overall view of the teeth, jaws, and surrounding tissues. However, there are instances where radiographic images are rejected or marked as inadequate based on the required quality standards. Reject analysis is a method of evaluation that involves analyzing rejected dental radiographic images. This research will identify the most common factors contributing to image rejection and provide recommendations for improving the quality of dental radiographic images Methode : The type of scientific study in this research is quantitative and descriptive. The research was conducted at the Radiodiagnostic Department of the Dental Hospital, Muhammadiyah University of Semarang. The total sample size taken was 301 extraoral radiographic films. The research data were obtained through a retrospective survey approach and observation method. The analysis was performed using Microsoft Excel 2021 application. Result : The primary factors contributing to film rejection are patient movement (50%), patient positioning (25%), and device settings (25%). Film rejection for extraoral radiographic examinations consisted of 2 films in Panoramic examinations, accounting for 50%, and 2 films in Cephalometric examinations, also accounting for 50% Conclusion : The film rejection ratio for extraoral dental radiography examinations conducted at the Radiodiagnostic Department of the Dental Hospital, Universitas Muhammadiyah Semarang, remained below the normal limit value of 1.29%.

Comparison of Ultrasonic Phased Array and Film Radiography in Detection of Artificially Embedded Defects in Welded Plates.

Ultrasonic and radiographic testing are generally two basic methods for volumetric (internal) defect detection in non-destructive testing. Since both methods are commonly used for the same thing, the question arises as to whether both are equally capable of detecting some commonly occurring defects in manufacturing. Commonly occurring defects are generally considered to be fusion defects, drilled holes (which act as pores), etc. To prove or disprove the hypothesis that both methods can generally be used to detect these defects, an experiment was conducted using three welded plates with artificially inserted defects. The welded plates had multiple defects that were intentionally placed close to each other to further complicate the interpretation of the UT results. UT investigation was based on phased-array technology with a multi-element probe. RT investigation was performed with an X-ray machine. Both investigations were based on the respective European standards: for UT, EN ISO 17640, and for RT, EN ISO 17636-1. The results and conclusions from the experiment are presented in this paper.

Accuracy of Leg Length and Offset Measurements During Total Hip Arthroplasty Using an Imageless Navigation System.

Introduction Leg length and offset are important considerations in total hip arthroplasty (THA). Navigation systems are capable of providing intra-operative measurements of leg length and offset, and high accuracy has been shown in experimental studies. This study assesses the accuracy of an imageless navigation system with a pinless femoral array (Hip 5.1, BrainLAB, Feldkirchen, Germany) in measuring leg length and offset changes in vivo. Methods A prospective, consecutive series of 37 patients undergoing navigated THA were included in the study. Intra-operative measurements of leg length and offset were recorded using the navigation system. For each patient, pre- and post-operative digital radiographs were scaled and analyzed to provide radiographic measurements for comparison. Results Measurements of leg length change made by the navigation system showed a strong correlation with the size of change measured radiographically (R = 0.71; p<0.0001). The mean difference between the radiographic and navigational measurement was 2.6mm ± 3.0mm (0.0-16.0mm) (mean, SD, range). The navigation system was accurate to within 1mm of the radiographic measurement in 49% of cases, within 2mm in 66% of cases, and within 5mm in 89% of cases. Measurements of offset change by the navigation system also showed a correlation with radiographic measurements, albeit less pronounced (R = 0.35; p=0.035). The mean difference between navigational and radiographic measurements was 5.5mm ± 4.7mm (0.0-16.0mm) (mean, SD, range). The navigation system was accurate within 1mm of the radiographic measurement in 22% of cases, within 2mm in 35% of cases, and within 5mm in 57% of cases. Conclusions This research demonstrates in vivo that an imageless, non-invasive navigation system is a reliable tool for intra-operative leg length (accurate within 2mm) and to a lesser extent offset measurement (accurate within 5mm) when compared to standard practice of plain film radiographs.

Silver Recovery from used X-Rays and Other Silver-Rich Diagnostic Radiography Films: A Review

Silver Recovery from used X-Rays and Other Silver-Rich Diagnostic Radiography Films: A Review

Associated factors of osteoporosis and vascular calcification in patients awaiting kidney transplantation

IntroductionPretransplant osteoporosis and vascular calcification probably increase the risk of fractures and cardiovascular events after kidney transplantation. In the present study, we investigated the related risk factors of osteoporosis and vascular calcification among end-stage renal disease (ESRD) patients awaiting kidney transplantation.MethodsA total of 221 ESRD patients (age, 43.4 ± 14.3 years; 125 males and 96 females; median dialysis duration, 61.0 m) awaiting kidney transplantation were enrolled in this cross-sectional study. Serum levels of bone turnover markers and intact parathyroid hormone (iPTH) were analyzed from fasting morning blood samples. Dual-energy X-ray absorptiometry was used to measure bone mineral density (BMD). Vascular calcification was evaluated by lateral abdominal radiography and plain radiographic films of the pelvis and hands.ResultsThe osteoporosis prevalence was 27.6% in this cohort of kidney transplantation candidates, and the prevalence of vascular calcification was 51.1%. The related factors for osteoporosis and vascular calcification were similar and included older age, longer dialysis duration, parathyroid hyperplasia, and higher levels of iPTH and bone turnover markers. In the multivariable regression model, age and iPTH were independent risk predictors of both vascular calcification and osteoporosis. There were strong, positive correlations between iPTH and all bone turnover markers. The moderate and severe hyperparathyroidism (iPTH 600–1499 pg/ml and iPTH 1500 pg/ml) were related to reduced serum albumin and hemoglobin levels.ConclusionThe involvement of high iPTH levels in vascular calcification, osteoporosis, and malnutrition indicated the need of treating hyperparathyroidism early in patients awaiting kidney transplantation. Prospective studies are needed to further examine the utility of bone turnover markers.

Reliability of a Novel Preoperative Protocol for Determining Graft Sizes for Superior Capsular Reconstruction Using Plain Film Radiography.

Superior capsular reconstruction (SCR) for massive, irreparable rotator cuff tears involves anchoring a graft between the superior glenoid and the greater tuberosity of the humerus. Optimizing the graft size is important. We aimed (1) to evaluate the reliability of plain film radiography in determining graft size for SCR and (2) to create a database to help predict future graft sizes. An inter- and intra-rater reliability trial was conducted on 10 and 6 subjects with healthy shoulders, respectively, using plain film radiography to measure the distance between the superior glenoid and the supraspinatus footprint. The subjects were positioned upright with an abduction pillow modified to hold the shoulder at 30° abduction and 45° external rotation, afterwhich a true antero-posterior shoulder radiograph was captured. Thirty subjects were recruited for the database and grouped using the aforementioned protocol. The inter-rater and intra-rater trial agreement was excellent, with intraclass correlation coefficients of 0.94 (95% CI) and 0.76 (95% CI), respectively. Three medio-lateral patch sizes, of 33 mm, 38 mm, and 47 mm, were proposed based on the protocol in 30 subjects. Plain film radiography demonstrated excellent reliability in measuring the distance between the superior glenoid and the supraspinatus footprint. Three ordinal patch sizes are proposed.

Detectability of Small True-T Hole Image Quality Indicators by Digital Radiographic Techniques

Image quality indicators (IQIs) are used to ensure quality in radiography. The requirements for hole-type IQIs have changed from MIL-STD-453-C (US DOD 1984) to ASTM E1742 and E1025 (ASTM 2018a, 2018b). For materials thinner than 0.50 in., the 2-2T hole does not represent 2% sensitivity. E1025 introduced true-T hole IQIs, where the 2-2T hole represents 2% sensitivity. Stainless steel true-T hole IQIs were fabricated using drills and a plasma-focused ion beam instrument. They were imaged using digital radiography (DR), computed radiography, and X-ray film to determine the limit of their visibility. DR was able to detect holes on the order of 2 to 3 pixels in diameter. All three techniques were able to detect the 2T hole in the number 4 IQI while DR was able to detect it in the number 3 IQI. These hole sizes are near the limit where geometric magnification would be required. The better sensitivity of DR is probably a result of being able to minimize fixed structural noise. Presently, for materials thinner than 0.50 in., there is the option to use IQIs defined by either E1742 Annex A1 or E1025. It is recommended that inspection procedures require a particular sensitivity percent that would necessitate the use of a specific IQI.

An expert knowledge-empowered CNN approach for welding radiographic image recognition

Non-destructive testing of welds based on the radiographic image is crucial for improving the reliability of aerospace structural components. The deep learning method represented by the convolutional neural network (CNN) has received extensive attention in welding radiographic image recognition (WRIR) owing to its powerful feature adaptive extraction ability. However, CNN-based WRIR faces key challenges of small sample size and poor explainability. Inspired by the process of interpreting radiographic film by experts, expert knowledge-empowered CNN for WRIR is proposed. Two self-supervised learning (SSL) tasks for radiographic image deblurring and brightness adjustment are designed to model expert experience. The expert knowledge learned from the SSL process is used to guide the CNN to identify weld defects. The results show that the proposed method improves the inductive bias of the CNN model, owns a faster convergence speed and recognition accuracy under the condition of small sample size, and reaches 97.65% of the comprehensive evaluation index F1-score. Moreover, the expert knowledge learned from the SSL process and the decision-making basis of the CNN model are visualized from both global and local aspects, which improve the explainability of CNN-based WRIR.

123 Early Postural Stability Changes in Patients Undergoing Correction of Spinal Deformity

INTRODUCTION: Adult spinal deformity (ASD) is an increasingly prevalent cause of pain and disability. It is known that ASD correction results in improved alignment, but not whether this alignment results in objective improvements in postural stability. METHODS: A retrospective review of a prospectively maintained database identified 16 patients undergoing ASD correction surgery with five or more segments. Balance was assessed via a force plate pre- and three months postoperatively. Participants were instructed to stand still, with their hands at their sides and eyes open. Center of pressure (COP) and center of gravity (COG) parameters were analyzed and used to derive head sway in the Dubousset cone of economy (COE). Spinopelvic parameters (PI, PT, SVA, and LL) on standing scoliosis radiographic films were also measured pre- and three months postoperatively. RESULTS: In our 16-patient series, there was a mean age of 61.3 years-old, and a median of 10 segments fused. Postoperative force plate assessment showed a decrease in total COP sway and sway velocity (p &lt; 0.05). Coronal COP sway and sway velocity also decreased (p &lt; 0.05). There was a decrease in total, coronal and sagittal COG sway and sway velocity postoperatively (p &lt; 0.05). In the COE, total head sway decreased (p &lt; 0.05). PT remained unchanged following surgical correction, while LL and SVA improved from 44.9° to 56.7° (p &lt; 0.01) and 82.2 to 22.5 mm (p &lt; 0.01), respectively. PI-LL mismatch also improved from 16.2° to 4.8° (p &lt; 0.01). CONCLUSIONS: Following long segment fusion for ASD, postural stability may improve as early as three months, concomitant with improved spinopelvic alignment. We believe force plate assessment warrants further study for postoperative evaluation of postural alignment and clinical outcomes in ASD patients.

Investigation of Radiochromic Film Use for Source Position Verification through a LINAC On-Board Imager (OBI)

Background and Objectives: Quality assurance is an integral part of brachytherapy. Traditionally, radiographic films have been used for source position verification, however, in many clinics, computerized tomography simulators have replaced conventional simulators, and computerized radiography systems have replaced radiographic film processing units. With these advances, the problem of controlling source position verification without traditional radiographic films and conventional simulators has appeared. Materials and Methods: In this study, we investigated an alternative method for source position verification for brachytherapy applications. Source positions were evaluated using Gafchromic™ RTQA2 and EBT3 film and visually compared to exposed RTQA radiochromic film when using a Nucletron Oldelft Simulix HP conventional simulator and a Gammamed 12-i brachytherapy device for performance evaluation. Gafchromic film autoradiography was performed with a linear accelerator (LINAC) on-board imager (OBI). Radiochromic films are very suitable for evaluation by visual inspection with a LINAC OBI. Results: The results showed that this type of low-cost, easy-to-find material can be used for verification purposes under clinical conditions. Conclusions: It can be concluded that source-position quality assurance may be performed through a LINAC OBI device.