Conventional Film Radiography Research Articles

GafChromic® RTQA film for routine quality assurance of high-energy photon beams

Self-developing film offers many advantages over conventional radiographic verification film for routine radiotherapy quality assurance (QA). This paper presents results from an initial evaluation of a beam measurement system using GafChromic® RTQA film and a flatbed scanner. Variability and energy dependence of the film calibration and accuracy of scanner readout are investigated in the context of QA measurements. For exposures of film between 2 and 4 Gy, the system is adequate for measurement of beam dimensions, as in multi-leaf collimator (MLC) offsets and secondary jaw calibrations, where agreement with conventional film measurements is within 0.5 mm. However, the measurement of absolute dose is subject to errors of about 25 cGy.

A Comparison Between Two Types of Radiographic Film for Accuracy of Measurements of Approximal Osseous Defects

The purpose of this study was to compare two types of conventional radiographic film: Ekta-speed plus and Insight (Eastman Kodak Co, Rochester NY, USA) for accuracy of measurements of approximal bone loss. Four dried human mandibles with complete dentition were selected. Radiographic images were made with a standardized technique. Mesial and distal bone levels on the mandibular premolar and molar teeth were measured on the two types of radiographs (Ekta-speed plus and Insight) by nine observers. The data obtained by the observers were compared with the primary investigators' corresponding measurements, which served as "the ground truth" for this study. The results of the analysis of variance (ANOVA) demonstrated a significant difference for the Ekta-speed plus film (p = .001), but the difference was not clinically significant. The level of intra-rater reliability was high for the observers (0.969 to 0.990). Performance of Ekta-speed plus and Insight films was found to be similar.

Interexaminer agreement in caries radiographic diagnosis by conventional and digital radiographs

The purpose of this research was to compare two digital storage phosphor systems and conventional film, as well as verify the interexaminer agreement in radiographic diagnosis on occlusal and proximal cavities. Two digital systems and conventional radiographic film were used to evaluate 144 tooth surfaces with and without cavities; the radiographs were analyzed and scored in a scale of 4 points. Thirteen undergraduates and an oral radiologist participated as examiners. A light microscopy analysis was accomplished in order to validate the research. The results showed that there was no significant difference between the radiographic systems, however all of them had significant differences when compared to light microscopy, except for the Digora system on the proximal surface when the radiologist was the examiner. In the interexaminer evaluation, a moderate agreement level was obtained, and a fair to moderate level was obtained between the students and the oral radiologist. Regarding the validation (sensitivity, specificity, positive predict and negative predict) the values were similar between students and the oral radiologist, except for the sensitivity value on the occlusal surface. The students had the highest number of false-positive results and the oral radiologist the highest number of false-negative results.

Audit for extraoral radiographic examinations in a digital department

To investigate whether extraoral radiographs requested by clinicians were actually viewed by the clinicians after recording. Digital extraoral images recorded at the radiology department were tracked over a 1-year period. Digital images are communicated to the clinical departments through our Picture Archiving and Communication System and may be viewed at any computer which houses the image display and enhancement software "DigiView". DigiView keeps track of user actions, among others where and when an image is opened. An image was defined as viewed if it had been opened in DigiView within 3 months after it had been recorded. The number of opened and non-opened images was calculated in relation to the referring clinical departments/units in the dental school. 2374 digital extraoral images were requested by the clinical departments. Two-thirds of these images were requested from the orthodontic department. Twenty-two percent (n=346) of their requested images were not opened. The distribution of non-opened images for the other clinical departments was: oral surgery=3% (18 images); periodontology=17% (1 image); treatment planning=33% (1 image); prosthetic=5% (6 images); county=21% (8 images) and oral physiology=23% (6 images). Panoramic images constituted the majority (58%) of non-opened images. Twenty-six percent of the images were opened once, 15% were opened twice and 41% were opened three times or more. Digital imaging offers new possibilities for audit compared with conventional film radiography. It seems that custom in some disciplines rules the referral of patients to radiographic examination and that this may lead to over-prescription.

An in vitro comparison of root canal measurement in primary teeth

To compare the accuracy of root canal lengths in primary teeth determined by tactile sense, electronic apex locator, conventional radiography, and digital radiography in primary teeth. The study sample consisted of twenty 20 extracted, single-rooted primary teeth. A comparison was made between the working length measurements obtained by tactile sensation, electronic apex locator, conventional film, and digital radiography, using stereomicroscopic measurements to obtain real canal length. The mean readings obtained were 15.91+/-2.06 by tactile measurement, 15.94 94+/-1.42 by apex locator, 16.06+/-1.73 by conventional radiography, and 15.91+/-1.60 by digital radiography. No statistically significant differences were seen between the techniques.

Reformatted Visceral Protocol Helical Computed Tomographic Scanning Allows Conventional Radiographs of the Thoracic and Lumbar Spine to Be Eliminated in the Evaluation of Blunt Trauma Patients

Patients suffering high-energy injuries are at risk for occult thoracic and lumbar spine fractures, and the standard of care includes radiographic spine screening. Most such patients require computed tomographic (CT) scanning to screen for chest and/or abdominal visceral injury. Helical CT (HCT) scanning represents a major technologic change that allows data to be reformatted after the patient has left the radiology suite. We explored the possibility of using reformatted visceral protocol HCT scanning to replace radiographs of the thoracic and lumbar spine in the evaluation of seriously injured patients. A prospective evaluation of consecutive patients with thoracic and lumbar spine fractures admitted over a 12-month period to an urban Level I trauma center was completed. The ability of conventional radiography and reformatted HCT scanning to detect spine fractures was compared. Of 1,915 trauma patients admitted, 78 (4.1%), with an average Injury Severity Score of 21.3 +/- 1.2, sustained one or more thoracic (n = 35 patients) or lumbar (n = 43 patients) spine fractures. The sensitivity of reformatted HCT scanning as a screening test for spine fractures was 97% for thoracic and 95% for lumbar spine fractures, compared with a sensitivity of 62% for thoracic and 86% for lumbar conventional radiographs. Data obtained from HCT scanning performed to evaluate seriously injured multiple trauma patients for thoracic and abdominal visceral injury can be reformatted to screen for thoracic and lumbar spine fractures, providing accurate screening while eliminating the time, expense, and radiation exposure associated with conventional film radiography.

Mechanical Small Bowel Obstruction due to Intraluminal Thrombus in a Patient with Acute Leukaemia: Ultrasonic Findings

Conventional plain film radiography is the primary imaging procedure in cases of suspected bowel obstruction. With improvement in ultrasound (US) technology, it can be used as part of the evaluation of patients with an acute abdomen [1–3]. US can detect the level of bowel obstruction accurately, particularly in the presence of a gasless, fluid-filled plain abdominal film [4]. We report an unusual case of gastrointestinal bleeding and subsequent small bowel obstruction caused by thrombus in a patient with acute leukaemia. The diagnosis was based on the US findings and confirmed at emergency surgery. To our knowledge, such a case has been not described previously.

Reliability of detecting prosthesis/cement interface radiolucencies in total hip arthroplasty

A laboratory study assessed the reliability of detecting radiolucencies at the prosthesis/cement interface in femoral components for total hip replacement. Radiolucencies (thicknesses=0.1, 0.3, 0.5 and 0.7 mm) were created by randomly masking non-tip Gruen zones (six per stem) in a group of 72 matte-finish femoral components. Only half of all Gruen zones were masked. The femoral components were reproducibly implanted in composite fiberglass replicate femurs. Anteroposterior and lateral radiographs taken using conventional techniques were then presented to 10 experienced readers, who scored each of 432 non-tip Gruen zones for radiolucency presence or absence. The series-average radiolucency detection rate was 47.1%, with a breakdown of 9.8%, 20.7%, 69.8% and 88.0% for radiolucency thicknesses of 0.1, 0.3, 0.5 and 0.7 mm, respectively. The false positive rate was 7.5%. The findings argue strongly that in many or most instances, initial cement–prosthesis debonding is not reliably detected from conventional plain film radiographs. Radiolucencies of at least 0.7 mm width are necessary to be accurately detectable by most viewers.

Value of magnetic resonance tomography (MRI) in diagnosis of triplane fractures of the distal tibia

The rare transitional fractures occur in adolescents at a time of incomplete dosis of the epiphysis. The anatomy of this fracture type is complex with the fracture line running in multiple planes. Conventional plain film radiographs often underestimate the extent and geometry of the fracture due to its transverse components. This study was performed to asses the benefit of MR-imaging compared to plain film radiographs in diagnosis and analysis regarding fracture-type, anatomy and dislocation of fracture. During a time period of 18 months we treated 15 patients with a fracture of the distal tibial epiphysis. In addition to plain film radiographs they got MRI of the distal tibia. Plain film radiographs and MRI were anonymized and diagnosed by 2 surgeons and 2 radiologists. 12 transitional fractures were diagnosed in plain radiographs as well as MRI, but regarding our criteria as above, we found two wrong classifications of fracture-type, an underestimation of fracture dislocation of an average of 0.5 mm in plain film radiographs and two rotational dislocations were missed. The MRI was found to provide anatomical detail and information superior to plain film radiographs.

The implementation of digital sensors in maxillofacial radiography

Systems for intra-oral digital radiography in dentistry can be divided into two main groups: direct sensor systems and semi-direct or indirect sensor systems. Direct imaging is performed by a two-dimensional array of sensor elements. The size of a typical intra-oral CCD-sensor is approximately from 18 mm×24 mm to 30 mm×40 mm; the active area is somewhat smaller, because of the thickness of the packaging of the sensor. CCD-based imaging is now also available for panoramic and cephalometric radiography. Indirect (semi-direct) imaging is based on storage phosphor plates (SPP) imaging. The plate is positioned in the mouth of the patient behind the teeth, and exposed to radiation. The positioning of the sensor plate resembles very much the way conventional radiographic films are handled. SPP technology is also available for panoramic and cephalometric imaging. The purpose of radiography is to provide information to solve a particular diagnostic task. It is therefore very likely that the role of dedicated diagnostic software will become essential in the near future. The importance of dedicated software for diagnostic imaging will increase. As a result of worldwide research, more procedures will become available, for research as well as for use in general practice.

Evaluation of a Digital Measurement Tool to Estimate Working Length in Endodontics

The purpose of the study was to compare the segmental measurement tool from the Shick Technologies CDR digital system with the conventional film radiography measurement technique to determine preoperative working length. Natural extracted human teeth with varying degrees of root curvature were used. All teeth were imaged using the Shick Technologies CDR direct digital system and conventional E-speed film. Measurements from digital radiography and conventional film were compared with measurements made directly from the endodontic files. The Wilks' Lambda multivariate test was used. The mean measurement of each modality was compared with the other and with the gold standard. The test showed statistically significant differences between the two modalities at p<0.05. The mean measurements for both modalities were not significantly different from the gold standard. The modality most closely approaching the gold standard was the conventional film.

CT imaging based digitally reconstructed radiographs and their application inbrachytherapy

The aim of our study was to develop an algorithm to simulate thedigitally reconstructed radiograph (DRR) calculation process for differentbeam qualities (photon energies) in the range 50 keV to 12 MeV. This wasachieved using volumetric anatomical data for the patient obtained fromthree-dimensional diagnostic CT images. These DRR images can be used inthree-dimensional treatment planning for external beam radiotherapy as well asfor brachytherapy in the same way as conventional radiographic films. Theadvantages of using such DRRs in modern 3D brachytherapy treatment planningare shown. A number of tools are described, illustrating that theapplication of DRRs in brachytherapy is very useful.

Reproducibility in the Assessment of Caries Lesion Behaviour: A Comparison between Conventional Film and Subtraction Radiography

The purpose of this study was to compare reproducibility in the assessment of caries lesion behaviour in digital subtraction images and conventional radiographs. Ninety–seven pairs of conventional film bite–wings were included. The radiographs had been taken with a Kwik–Bite filmholder without further standardisation. The selection criterion was that at least one surface imaged in a bite–wing pair should show progresssion of a caries lesion from the first exposure to the second. The time interval between the bite–wings was 1–2 years. The radiographs were scanned into a personal computer and the two images from the same patient subtracted. Seven observers scored the subtraction images and the conventional films. The scale was based on no change/ change in surface appearance scored in the following categories: 0 = no change; 1 = development of a new caries lesion in enamel; 2 = development of caries lesion in enamel and dentine/progression of an existing enamel lesion into dentine/progression of a dentinal lesion further into dentine; 3 = development of secondary caries; 4 = new filling/change of filling/extension of filling. Cohen’s κ coefficients were calculated for intra– and inter–observer agreement for the two radiographic methods separately. The κ value served as the statistical sampling unit for testing differences between the two methods (Wilcoxon’s test for ranked pairs). The average intra–observer κ value was 0.875 (range 0.775–0.958) for the subtraction images and 0.758 (range 0.560–0.890) for the conventional radiographs. The difference was statistically significant (p<0.05). For inter–observer agreement, the κ values were lower than for intra–observer agreement. The average value was 0.678 (range 0.485–0.754) for the subtraction images and 0.701 (range 0.497–0.817) for the conventional radiographs (p>0.1). This study suggests a new way of comparing reproducibility in terms of κ values between diagnostic methods in clinical studies where accuracy cannot be evaluated. The subtraction method may be useful in the assessment of caries lesion behaviour in the clinic.

The effect of a Picture Archiving and Communications System (PACS) on diagnostic performance in the accident and emergency department

Objective—A study has been conducted to identify the benefits to the accident and emergency (A&E) department of a hospital wide Picture Archiving and Communications System (PACS). Methods—The study was conducted...

Occlusal Caries Detection with KaVo DIAGNOdent and Radiography: An in vitro Comparison

A new laser fluorescence method, KaVo DIAGNOdent, was tested with respect to reproducibility and validity and compared with radiography regarding accuracy in the detection of occlusal caries. Seventy–six extracted premolar and molar teeth were measured twice with DIAGNOdent under both wet and dry conditions, at an interval of 2 weeks. Conventional film radiographs were exposed. Microradiographic analysis of sections of the teeth served as the gold standard. Intra–class correlation coefficient and Pearson’s correlation coefficient were used to assess the reproducibility and the validity of the method, respectively. The influence of time and varying humidities on DIAGNOdent readings were analysed by two–way repeated measure ANOVA. ROC curves were plotted for DIAGNOdent readings and radiographic registration of caries by 6 observers, and the areas under the curves were compared using Student’s t test. Under both wet and dry conditions, the reproducibility of the DIAGNOdent method was excellent: R = 0.97 and 0.96, respectively. The diagnostic accuracy of DIAGNOdent was significantly better than that of radiography (p≤0.001). In this in vitro study of detection of occlusal caries, the diagnostic performance of the DIAGNOdent method was superior to that of radiography.

Serial Magnetic Resonance Imaging Evaluation of Operative Site After Fixation of Patellar Tendon Graft With Bioabsorbable Interference Screws in Anterior Cruciate Ligament Reconstruction

Summary: Magnetic resonance imaging (MRI) is accepted as the imaging procedure of choice for showing internal derangement of the knee. In contrast to metal implants, bioabsorbable interference screws do not produce an artifact and provide an opportunity to expand the evaluation of the postoperative anterior cruciate ligament (ACL) ligament repair. There is the potential to evaluate the implant, the graft, the adjacent tissue, and the surgically created bone tunnels. The purpose of this study was to evaluate with MRI the postoperative site of ACL patellar tendon autografts in which bioabsorbable screws were used for fixation. It was hypothesized that a time line of bone tissue changes resulting from this type of surgery could be developed based on the expanded evaluation of MRI. From January 1993 through October 1997, 270 patients underwent surgical repair of a disrupted native ACL. There were 173 men 97 women; the average age was 25.1 years. (range, 17 to 50 years). There were 155 right knees and 115 left knees. In addition to the conventional postoperative clinical assessment and plain film radiographs, opportunistic MRIs were obtained with the patient's permission. The examinations were performed at different postoperative intervals from the third postoperative day to 4 years postoperatively. A total 206 MRIs from various time intervals were available for study. The study protocol was designed to look for loss of integrity of the screws, adjacent fluid collection, tunnel widening, and tunnel healing or narrowing. The hypothesis was substantiated in this study. The use of MRI provided observations not available by other imaging methods. The absence of metal implants for fixation provided an opportunity to examine the adjacent tissue in detail and to form a time line of the tissue response in this type of surgery. Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 15, No 7 (October), 1999: pp 709–718

Magnetic resonance imaging in the diagnosis of acute injured distal tibiofibular syndesmosis.

This study assessed the diagnostic potential of magnetic resonance imaging for the evaluation of the tibiofibular syndesmosis. A total of 38 patients with an acute ankle trauma and clinical suspicion of a syndesmotic tear were prospectively studied with conventional plain film radiography and magnetic resonance imaging. Magnetic resonance imaging studies included plain T1-weighted (T1-w) and T2-weighted (T2-w) sequences and contrast-enhanced T1-w sequences 0 to 3 days after trauma. All images were read by two independent radiologists before surgical intervention. Sensitivity and specificity were determined for the two observers and the concordance of the two observers were calculated using the interobserver analysis (Kappa-Test). Intraoperative inspection (n = 21) revealed rupture of the anterior tibiofibular ligament (ATIF) in 15 patients, intact ATIF in 6 patients, and intact posterior tibiofibular ligament (PTIF) in 21 cases. Clinical and follow-up examinations revealed an intact syndesmotic complex in another 17 patients. Primary diagnostic criteria for diagnosing a ligamentous tear included tibiofibular diastasis in conventional plain films; nonvisualization of the ATIF; an abnormal course, a wavy, irregular contour of the ligament; increased signal intensity of the ligament in T2-w sequences, in plain T1-w sequence, and marked enhancement in T1-w after contrast. Important secondary signs were defined as joint fluid in the tibiofibular space and prolapse of interspace fat. Highest diagnostic accuracy was achieved if three or more diagnostic criteria could be visualized. Both readers performed best with the enhanced T1-weighted and the T2-weighted images in transverse orientation. The interobserver analysis resulted in high concordance: Kappa = 0.9 (confidence interval: 0.76 to 1.00) for all patients, and in Kappa = 0.76 (confidence interval: 0.45 to 1.0) for surgically treated patients. Magnetic resonance imaging of the syndesmotic complex is a highly sensitive and specific tool for the pretherapeutic-evaluation of syndesmotic injury.

ESTIMATING DISTANCES ON DIRECT DIGITAL IMAGES AND CONVENTIONAL RADIOGRAPHS

Digital images produced by direct sensor systems are much larger than conventional radiographic film images because of monitor resolution and digital image file sizes. This difference in size may introduce difficulties when estimating distances (for example, during endodontic treatment). The aim of this study was to compare observers' estimates of distances on digital images with those of conventional radiographs.

Radiotherapy of Vertebral Hemangiomas

Between 1975 and 1996, 14 patients (11 females, 3 males) with vertebral hemangioma received treatment with radiotherapy. Thirteen patients had a history of back pain or lumbago and 2 patients had neurological symptoms such as sensory impairment or paraplegia. The standard dose administered was 36 Gy in 18 fractions (five treatments per week). In the 13 patients with pain, this was completely or partially relieved. The condition of a man with hypesthesia of the legs deteriorated and a woman with paraplegia who was treated with decompressive laminectomy followed by radiotherapy recovered completely after irradiation. CT scan before irradiation showed thickened trabeculae as small punctate areas of sclerosis in all patients. At MR imaging before irradiation, T2-weighted MR images showed areas of high intensity in all patients and MR images demonstrated lesion enhancement. However, none of the patients who were treated successfully with radiation demonstrated any changes of the affected vertebra in the conventional radiographic films, CT scan or MR imaging, even 5 years after irradiation. Radiological imaging is indispensable for the diagnosis of vertebral hemangiomas but does not appear to be useful for evaluating the effects of radiotherapy.

Dose reduction of two digital sensor systems measuring file lengths

Objectives The aim of this study was to determine the effect of dose reduction on the image quality of two sensor systems with automatic greyscale adjustment. Study designs Two digital sensor systems, Sidexis (Siemens, Bensheim, Germany) and Digora (Soredex, Helsinki, Finland), were tested. The image quality of the systems was determined by comparing lengths of endodontic files (025, 020, 015, and 010 files) and a premolar root in the digital images with lengths on conventional radiographic films. For the experiments the exposure was changed to 100%, 50%, 25%, 12.5%, 6.25%, and 3.125% of that for Ektaspeed films. Results The lengths of 025 and 020 files and the premolar root in the digital images were comparable with the lengths on films even if the exposure was reduced to 6% of that used for Ektaspeed films. The lengths of 015 files reduced as the exposure was reduced. The lengths of 010 files were significantly shorter than the lengths on films. Conclusions With the systems tested, a dose reduction of approximately 95% compared with Ektaspeed films is possible to determine the lengths of a premolar root and 025 and 020 files. For thinner objects a dose reduction is questionable.