bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Royal Australian and New Zealand College of Radiologists (RANZCR) relative value unit workload model, its limitations and the evolution to a safety, quality and performance framework
Authors: Pitman A , Jones DN , Stuart D , Lloydhope K , Mallitt K , O'Rourke P 
Published: September 2009

SummaryThe study reports on the evolution of the Australian radiologist relative value unit (RVU) model of measuring radiologist reporting workloads in teaching hospital departments, and aims to outline a way forward for the development of a broad national safety, quality and performance framework that enables value mapping, measurement and benchmarking. The Radiology International Benchmarking Project of Queensland Health provided a suitable high‐level national forum where the existing Pitman–Jones RVU model was applied to contemporaneous data, and its shortcomings and potential avenues for future development were analysed. Application of the Pitman–Jones model to Queensland data and also a Victorian benchmark showed that the original recommendation of 40 000 crude RVU per full‐time equivalent consultant radiologist (97–98 baseline level) has risen only moderately, to now lie around 45 000 crude RVU/full‐time equivalent. Notwithstanding this, the model has a number of weaknesses and is becoming outdated, as it cannot capture newer time‐consuming examinations particularly in CT. A significant re‐evaluation of the value of medical imaging is required, and is now occurring. We must rethink how we measure, benchmark, display and continually improve medical imaging safety, quality and performance, throughout the imaging care cycle and beyond. It will be necessary to ensure alignment with patient needs, as well as clinical and organisational objectives. Clear recommendations for the development of an updated national reporting workload RVU system are available, and an opportunity now exists for developing a much broader national model. A more sophisticated and balanced multidimensional safety, quality and performance framework that enables measurement and benchmarking of all important elements of health‐care service is needed.
Vertebroplasty in the management of traumatic burst fractures: A case series
Authors: Doody O , Czarnecki C , Given MF , Lyon Stuart M 
Published: September 2009

SummaryThis study aimed to assess the role of percutaneous vertebroplasty (VP) in the management of acute traumatic burst fractures. We describe three cases where percutaneous VP was carried out for traumatic non‐osteoporotic burst vertebral fractures. For clinical symptoms and the effect of the VP procedure to be assessed, all patients completed a visual analogue scale and a mobility score before the procedure and at day 1 and 3 months post procedure. Improvements in both pain and mobility scores immediately post procedure were seen in all patients, and these results persisted at 3‐month follow up. Percutaneous VP provided a successful, minimally invasive treatment of these patients' traumatic fractures while avoiding major surgical procedures and associated surgical morbidity and complications.
Invasive breast cancers detected by screening mammography: A detailed comparison of computer‐aided detection‐assisted single reading and double reading
Authors: Cawson JN , Nickson C , Amos A , Hill G , Whan AB , Kavanagh AM 
Published: September 2009

SummaryTo compare double reading plus arbitration for discordance, (currently best practice, (BP)) with computer‐aided‐detection (CAD)‐assisted single reading (CAD‐R) for detection of invasive cancers detected within BreastScreen Australia. Secondarily, to examine characteristics of cancers detected/rejected using each method. Mammograms of 157 randomly selected double‐read invasive cancers were mixed 1:9 with normal cancers (total 1569), all detected in a BreastScreen service. Cancers were detected by two readers or one reader (C2 and C1 cancers, ratio 70:30%) in the program. The 1569 film‐screen mammograms were read by two radiologists (reader A (RA) and reader B(RB)), with findings recorded before and after CAD. Discordant findings with BP were resolved by arbitration. We compared CAD‐assisted reading (CAD‐RA, CAD‐RB) with BP, and CAD and arbitration contribution to findings. We correlated cancer size, sensitivity and mammographic density with detection methods. BP sensitivity 90.4% compared with CAD‐RA sensitivity 86.6% (P = 0.12) and CAD‐RB 94.3% (P = 0.14). CAD‐RB specificity was less than BP (P = 0.01). CAD sensitivity was 93%, but readers rejected most positive CAD prompts. After CAD, reader's sensitivity increased 1.9% and specificity dropped 0.2% and 0.8%. Arbitration decreased specificity 4.7%. Receiving operator curves analysis demonstrated BP accuracy better than CAD‐RA, borderline significance (P = 0.07), but not CAD‐RB. Secondarily, cancer size was similar for BP and CAD‐R. Cancers recalled after arbitration (P = 0.01) and CAD‐R (P = 0.10) were smaller. No difference in cancer size or sensitivity between reading methods was found with increasing breast density. CAD‐R and BP sensitivity and cancer detection size were not significantly different. CAD‐R specificity was significantly lower for one reader.
Comparison of paper print and soft copy reading in plain paediatric radiographs
Authors: Maydell AT , Andronikou S , Ackermann C , Bezuidenhout AF 
Published: September 2009

SummaryWith the introduction of a Picture Archiving and Communication System, Computed (CR) and Digital Radiography (DR), reading digital images takes place from a computer screen. Laser paper print rather than laser film would be a significantly more cost‐effective option for hard copy production, but would need to demonstrate acceptable diagnostic quality compared to the reference standard of screen reading. A comparative study of 51 digital paediatric CR radiographs presented in laser paper print and soft copy format to determine the diagnostic value of the paper print when compared to the reference standard of screen reading. Chest radiography had a poor sensitivity of 66.1% while musculoskeletal and abdominal radiography had acceptable sensitivities of 90% and 99%, respectively. Specificity was excellent for the different regions (98.6–99.5%). The paper print format should not be used for diagnostic purposes in paediatric chest radiography, but may still be used for demonstration when accompanied by the radiology rapport obtained from soft copy reading. Further studies would be needed to investigate the use of paper prints in abdominal and musculoskeletal radiography owing to the low number of abdominal radiographs and lack of musculoskeletal case variety in our study.
The effect of an intensive nutritional program on daily set‐up variations and radiotherapy planning margins of head and neck cancer patients
Authors: Mercuri A , Joon D Lim , Wada M , Rolfo A , Khoo V 
Published: September 2009

SummaryThis is a prospective case‐control study to assess nutritional supplementation in limiting weight loss and its impact on daily set‐up variations and planning target volume (PTV) margins in head and neck (H&N) radiotherapy (RT). Twenty sequential H&N patients were recruited for this study. Ten patients had a percutaneous endoscopic gastrostomy (PEG) tube inserted prior to RT and 10 did not. PEG use was determined by departmental guidelines for patients considered at high risk for weight loss. Daily 2D electronic portal images were taken for orthogonal verification. Set‐up variations were determined for both PEG and non‐PEG patients by calculating systematic (Σ) and random (σ) errors, and PTV margins were derived. PEG patients lost less weight (P = 0.04) over the course of RT and had a reduction in set‐up variation in the superior–inferior (SI) and anterior–posterior (AP) planes compared to those without. Mean correctional shifts in mm (range) for PEG patients were: Right–Left (RL) 0.1 (−1.9–2.1), SI −1.7 (−2.9–0.0), AP −0.4 (−2.0–0.8), and for non‐PEG patients were: RL −0.2 (−2.7–1.3), SI −1.3 (−3.1–1.0), AP 0.4 (−1.5–2.8). The adapted PTV margins (mm) in the RL, SI and AP planes, respectively, for PEG patients were 4.1, 3.3 and 3.6, and for non‐PEG were 3.9, 4.9 and 4.8. Intensive enteral support maintained weight stability in H&N patients considered at risk of weight loss during RT and this was associated with reduced set‐up variation.
Breed‐specific variation of hematologic and biochemical analytes in healthy adult Bernese Mountain dogs
Authors: Nielsen Lise , Kjelgaard‐Hansen Mads , Jensen Asger Lundorff , Kristensen Annemarie T. 
Published: September 2009

Background:Hematology and serum biochemistry reference intervals in dogs may be affected by internal factors, such as breed and age, and external factors, such as the environment, diet, and lifestyle. In humans, it is well established that geographic origin and age may have an impact on reference intervals and, therefore, more specific reference intervals are sought for subpopulations.Objective:The objective of this study was to validate and transfer standard laboratory reference intervals for healthy Bernese Mountain dogs and to create new intervals for analytes where the established laboratory reference intervals were rejected.Methods:The procedure was performed using the human Clinical and Laboratory Standards Institute‐approved model modified for veterinary use. Thirty‐two dogs were included in the study using a direct a priori method, as recommended.Results:While 23 of the standard laboratory reference intervals were readily validated, 7 of the analytes (eosinophils, MCHC, alkaline phosphatase [ALP], γ‐glutamyltransferase, total bilirubin, amylase, and cholesterol) required new reference intervals according to the standard. These were calculated using the robust method. In particular, the new reference range for ALP was wide compared with the established laboratory reference interval. No clinical causes were found for differences in the results of these analytes.Conclusion:We found significant differences in 7 hematologic and serum biochemical analytes for which a breed‐specific variation appears to be the most plausible explanation. Breed‐specific reference intervals for Bernese Mountain dogs will help avoid misinterpretation of laboratory results in the diagnostic process.
A theoretical study on phase‐contrast mammography with Thomson‐scattering x‐ray sources
Authors: De Caro Liberato , Giannini Cinzia , Bellotti Roberto , Tangaro Sabina 
Published: September 2009

Purpose:The x‐ray transmitted beam from any material/tissue depends on the complex refractive index, where is responsible for the phase shift and is for the beam attenuation. Although for human tissues, the cross section is about 1000 times greater than the ones in the x‐ray energy range from 10 to 150 keV, the gain in breast tumor visualization of phase‐contrast mammography (PCM) with respect to absorption contact imaging (AI) is limited by the maximum dose that can be delivered to the patient. Moreover, in‐line PC imaging (PCI) is the simplest experimental mode among all available x‐ray PCI techniques since no optics are needed. The latter is a fundamental requirement in order to transfer the results of laboratory research into hospitals. Alternative to synchrotron radiation sources, the implementation of relativistic Thomson‐scattering (TS) x‐ray sources is particularly suitable for hospital use because of their high peak brightness within a relatively compact and affordable system. In this work, the possibility to realize PCM using a TS source in a hospital environment is studied, accounting for the effect of a finite deliverable dose on the PC visibility enhancement with respect to AI.Methods:The contrast‐to‐noise ratio of tumor‐tissue lesions in PCM has been studied on the bases of a recent theoretical model, describing image contrast formation by means of both wave‐optical theory and the mutual coherence formalism. The latter is used to describe the evolution, during wave propagation, of the coherence of the wave field emitted by a TS source. The contrast‐to‐noise ratio for both PCI and AI has been analyzed in terms of tumor size, beam energy, detector, and source distances, studying optimal conditions for performing PCM. Regarding other relevant factors which could influence “tumor” visibility, the authors have assumed simplified conditions such as a spherical shape description of the tumor inclusion, a constant surrounding background, ideal conditions for the calculus of the contrast‐to‐noise ratio.Results:The results show the possibility to enhance with PCI the signal‐to‐noise ratio for features in the submillimeter scale. This finding could give PCM a great advantage with respect to AI, opening the possibility to decrease the number of wrong diagnoses before histological exams. The results agree with experimental evidences obtained by Dreossi et al. [D. Dreossi et al., “The mammography project at the SYRMEP beamline,” Eur. J. Radiol. 68, S58–S62 (2008)] with real PCM using synchrotron radiation.Conclusions:The challenging characteristics of TS sources, suitable for PCM, should be fluxes of at least emitted by very small sources of about , together with moderate energy spreads (less than 10%) in order to realize both sufficient spatial coherence and enough fluence on the patient, collecting images in reasonable exposure times. These fluxes will be achieved by next generation TS sources which are already under development.
Replacement correction factors for cylindrical ion chambers in electron beams
Authors: Wang L. L. W. , Rogers D. W. O. 
Published: September 2009

Purpose:In the TG‐21 dosimetry protocol, for cylindrical chambers in electron beams the replacement correction factor (or the product in the IAEA's notation), was conceptually separated into two components: the gradient correction accounting for the effective point of measurement and the fluence correction dealing with the change in the electron fluence spectrum. At the depth of maximum dose , is taken as 1. There are experimental data available at for the values of (or ). In the TG‐51 dosimetry protocol, the calibration is at the reference depth where is required for cylindrical chambers and is unknown and so the measured values at are used with the corresponding mean electron energy at . Monte Carlo simulations are employed in this study to investigate the replacement correction factors for cylindrical chambers in electron beams.Methods:Using previously established Monte Carlo calculation methods, the values of and are calculated with high statistical precision for cylindrical cavities of a variety of diameters and lengths in a water phantom irradiated by various electron beams. The values of as defined in the TG‐51 dosimetry protocol are also calculated.Results:The calculated values of the fluence correction factors are in good agreement with the measured values when the wall correction factors are taken into account for the plane‐parallel chambers used in the measurements. An empirical formula for for cylindrical chambers at in electron beams is derived as a function of the chamber radius and the beam quality specifier .Conclusions:The mean electron energy at depth is a good beam quality specifier for. Thus TG‐51's adoption of at with the same mean electron energy for use at is proven to be accurate. The values of for a Farmer‐type chamber as defined in the TG‐51 dosimetry protocol may be wrong by 0.3% for high‐energy electron beams and by more than 1% for low‐energy electron beams.
Investigation of a source for intra‐ocular treatment of wet age‐related macular degeneration
Authors: Holmes Shannon M. , Micka John A. , DeWerd Larry A. 
Published: September 2009

Purpose:The purpose of this study is to perform an extensive investigation of an approximately long source designed for treating wet age‐related macular degeneration.Methods:As part of this investigation, a NIST‐traceable absorbed dose to water calibration technique was established, and a source deployment verification test was developed. The influence of treatment cannula construction tolerance on the measurements as well as the dose delivered to the patient was investigated using the Monte Carlo code MCNP5. Variation between production cannulae was quantified experimentally using a well‐type ionization chamber, and additional measurements along with Monte Carlo calculations of the collimating insert used for source deployment verification were performed to validate the model.Results:Maximum variation in the integrated target dose was seen when the source was shifted laterally within the treatment cannula. For the well chamber measurements, the observed standard deviation in ionization current for a single source placed in different reference cannulae was, with a maximum observed range of less than . Clinical cannulae in the collimating insert showed an average of of the reference signal when sources were fully deployed compared to 18.5% predicted by Monte Carlo calculations. This discrepancy has been attributed primarily to construction of the collimator since the collimation gap was observed to be approximately smaller than specified. Construction tolerance of the well chamber insert as well as position tolerance of the cannula tip were both investigated, and their influence on the predicted signal was quantified. Additional measurements along with Monte Carlo based calculations of the collimating insert with polyethylene spacers added to the setup were performed to validate the Monte Carlo model. The shimmed Monte Carlo and measured data agree to within 1%, which is a magnitude difference of approximately 0.1% of the reference signal.Conclusions:This investigation confirms that the signal for an acceptably deployed source in the collimating insert is between 17.5% and 21.5% of the reference signal, as calculated using Monte Carlo models. Clinical cannulae for which the source deployment verification measurement falls outside the acceptable range should not be used to treat patients.
Monte Carlo evaluations of the absorbed dose and quality dependence of in radiotherapy photon beams
Authors: Chen Shao Wen , Wang Xue Tao , Chen Li Xin , Tang Qiang , Liu Xiao Wei 
Published: September 2009

Purpose:The purpose of this work was to evaluate the absorbed dose to dosimeter at various depths of water phantom in radiotherapy photon beams by Monte Carlo simulation and evaluate the beam quality dependence.Methods:The simulations were done using EGSnrc. The cylindrical dosimeter was placed at the central axis of the water phantom at depths between 0.5 and 8 cm. The incident beams included monoenergetic photon beams ranging from 1 to 18 MeV, beams, Varian 6 MV beams using phase space files based on a full simulation of the linac, and Varian beams between 4 and 24 MV using Mohan's spectra. The absorbed dose to the dosimeter and the water at the corresponding position in the absence of the dosimeter, as well as absorbed dose ratio factor , was calculated.Results:The results show that depends obviously on the photon energy at the shallow depths. However, as the depth increases, the change in becomes small, beyond the buildup region, the maximum discrepancy of to the average value is not more than 1%.Conclusions:These simulation results confirm the use of dosimeter in radiotherapy photon beams and clearly indicate that more attention should be paid when using such a dosimeter in the buildup region of high‐energy radiotherapy photon beams.
Detectability of motions in AAA with ECG‐gated CTA: A quantitative study
Authors: Klein Almar , Oostveen Luuk J. , Greuter Marcel J. W. , Hoogeveen Yvonne , Schultze Kool Leo J. , Slump Cornelis H. , Klaas Jan Renema W. 
Published: September 2009

Purpose: ECG‐gated CT enables the visualization of motions caused by the beating of the heart. Although ECG gating is frequently used in cardiac CT imaging, this technique is also very promising for evaluating vessel wall motion of the aortic artery and the motions of (stent grafts inside) abdominal aortic aneurysms (AAA). Late stent graft failure is a serious complication in endovascular repair of aortic aneurysms. Better understanding of the motion characteristics of stent grafts will be beneficial for designing future devices. In addition, these data can be valuable in predicting stent graft failure in patients. To be able to reliably quantify the motion, however, it is of importance to know the performance and limitations of ECG gating, especially when the motions are small, as is the case in AAA. Since the details of the reconstruction algorithms are proprietary information on the CT manufacturers and not in the public domain, empirical experiments are required. The goal of this study is to investigate as to what extent the motions in AAA can be measured using ECG‐gated CT. The authors quantitatively investigate four aspects of motion in ECG‐gated CT: The detectability of the motion of objects at different amplitudes and different periodic motions, the temporal resolution, and the volume gaps that occur as a function of heart rate.Methods: They designed an experiment on a standard static phantom to empirically determine temporal resolution. To investigate motion amplitude and frequency, as well as patient heart rate, they designed dynamic experiments in which a home‐made phantom driven by a motion unit moves in a predetermined pattern.Results: The duration of each ECG‐gated phase was found to be , which corresponds to half of the rotation time and is thus in accordance with half scan reconstruction applied by the scanner. By using subpixel localization, motions become detectable from amplitudes of as small as in the direction and in the direction. With the rotation time used in this study, motions up to can be reliably detected. The reconstruction algorithm fills volume gaps with noisy data using interpolation, but objects within these gaps remain hidden.Conclusions: This study gives insight into the possibilities and limitations for measuring small motions using ECG‐gated CT. Application of the experimental method is not restricted to the CT scanner of a single manufacturer. From the results, they conclude that ECG‐gated CTA is a suitable technique for studying the expected motions of the stent graft and vessel wall in AAA.