bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dosimetry in the moving gap region in craniospinal irradiation
Authors: Cheng C-W , Das I J , Chen D-J 
Published: July 2009

Abstract
To minimize the risk of overlap of adjoining orthogonal fields in craniospinal irradiation, a skin gap is usually maintained between the caudal margin of the brain fields and the cephalic margin of the spine field. The moving gap technique (feathering) is commonly used to improve the dose in the gap region. Using Kodak XV ready-pack films and a polystyrene phantom, the dosimetry in the moving gap region at the depth of spinal cord for different gap sizes and feathering step sizes was studied. The dose profiles in the moving gap region with half-beam block set-up were also measured. Our results show that the combination of a small skin gap and a larger feathering step size results in a higher dose in the moving gap compared with that with identical gap and feathering step sizes. For example, with a 0.5 cm gap and 1 cm feathering step size, the dose in the moving gap region at depth of 5 cm ranges from 82 to 88% of the dose to the brain field. The corresponding dose range with 1 cm gap and 1 cm feathering step size is about 68–73%. With no gap and 1 cm feathering step, a dose range of 92–98% is achieved in the moving gap. The slightly steeper penumbra of a half-beam block used in the brain fields does not result in any dosimetric advantage in the moving gap compared with the conventional set-up when feathering is employed.
“But fell like autumn fruit that mellowed long” (John Dryden)
Authors: Yang W T , Evans R M , Chung S C 
Published: July 2009

An 89-year-old lady presented in the month of October with vomiting, colicky abdominal pain and abdominal distention. Three years prior to presentation she underwent a Bilroth I partial gastrectomy for a gastric carcinoid tumour. Physical examination revealed that she was dehydrated and there was a positive succussion splash.
A clinical diagnosis of high intestinal or gastric outlet obstruction was made and a contrast study of the upper gastrointestinal tract was performed (Figure 1). What abnormalities are shown and what is your diagnosis?
A large intraluminal filling defect is seen in the proximal jejunum causing obstruction. Mild thickening of the valvulae conniventes is seen proximally. The mass has a stippled appearance (Figure 2).
Knee effusions, radiology and acute knee trauma
Authors: Fishwick N G , Learmonth D J A , Finlay D B L 
Published: July 2009

Abstract
Sixty patients wth acute knee trauma were examined radiographically at presentation and subsequently examined under anaesthetic, when arthroscopy was performed. The aim was to assess whether a normal radiograph at presentation excluded significant knee pathology. Nine patients with significant pathology (25%) had normal radiographs at presentation.
A comparison of a conventional non-ionic contrast medium (iohexol) alone and with adrenaline and an iso-osmolar non-ionic contrast medium (iotrolan) in computed tomographic arthrography of the shoulder
Authors: Wellings R M , Davies A M , Pynsent P B , Cassar-Pullicino V N 
Published: July 2009

Abstract
The physico-chemical properties of the iso-osmolar dimeric contrast medium iotrolan offers potential advantages in computed tomographic arthrography (CTA). A trial was undertaken comparing iotrolan with iohexol to assess if these theoretical benefits produced an increase in the measured densities in a series of shoulder CTAs. The results showed that iotrolan did produce clinically useful increases in density when compared to a monomeric non-ionic contrast medium. The addition of adrenaline to the monomeric contrast medium produced a significant improvement in the computed tomography density which surpassed that offered by the dimeric contrast medium alone.
Physical evaluation of computed radiography as a mammographic X-ray imaging system
Authors: Workman A , Cowen A R , Brettle D S 
Published: July 2009

Abstract
The physical imaging properties of a computed radiography (CR) system operating under mammographic exposure conditions have been measured. These measurements include modulation transfer function (MTF), sensitometric response and noise power spectrum (NPS). These figures were used to derive signal-to-noise ratio (SNR) descriptors of the system performance. The same measures were derived for a mammographic film–screen system. The SNR properties of the CR system indicate superior low frequency performance over a wider dynamic range than the film–screen system. The spatial frequency dependent SNR properties of the CR system are, however, limited. The results of a psychophysical test support the results obtained from physical measurements. These results indicate that despite its limited sharpness, details of dimensions relevant to diagnosis in mammography (circular details 0.25 mm diameter to represent microcalcifications and 3 mm diameter to represent small masses) are reproduced using CR with SNRs which are at least comparable with those of a mammographic film–screen system.
Local control versus dose or overall time: from coefficients to percentages
Authors: Fowler J F , Chappell R 
Published: July 2009

Abstract
When clinical results are analysed to find the treatment variables which affect the outcome, two types of multivariate analysis are done. Firstly, a determination of which variables are important is made: from age, gender, stage, histology, total dose, overall time, etc. Secondly, a quasi-biological model may be set up which includes those variables, e.g.
Function (p) = Variable 1 + Variable 2 + … + α × dose + β × dose × (dose per fraction) − γ × (overall time)
where p is the probability of local control and “Function” is a logit or double-log function. The coefficients thus determined are often presented simply in raw form, or as ratios such as α/β or γ/α where any conversion factors from “Function (p)” to percentages are assumed conveniently to cancel out. However, it is mathematically possible to convert each coefficient directly into “percent change in local control per unit dose” (for α), or “percent per unit time” (for γ), without recourse to the obvious convenience of the ratios. These converted values are more understandable than the coefficients themselves. They mean the rate of change of local control with (for example) total dose if overall time and dose per fraction were held constant; or rate of loss of local control with prolongation if total dose and dose per fraction were held constant. Even though heterogeneity may alter these slopes considerably from the theoretically maximum Poisson slopes, they still tell us what is happening averaged over the group of patients being studied, with often interesting insights.
High dose rate versus low dose rate brachytherapy for squamous cell carcinoma of the cervix: an economic analysis
Authors: Jones G , Lukka H , O'Brien B 
Published: July 2009

Abstract
Brachytherapy is an established and important part of the management of invasive carcinoma of the cervix. Available evidence suggests that low dose rate (LDR) and high dose rate (HDR) are equivalent in terms of tumour control, adverse effects and survival. Proponents of outpatient HDR argue that it is less costly than LDR, but no economic evaluation has been published. We compared the costs of HDR and LDR (capital, operating, maintenance, source and operating costs) for Nucletron intracavitary equipment under alternative assumptions about the number of patients treated per year, the number of insertions per patient and discount rate. For example, for 3 HDR fractionations compared with 1 LDR fractionation, the LDR-3 (Nucletron) is the most cost-effective, practical machine for up to 40 patients per year. Although LDR-3 is more cost effective for a greater number of patients, HDR would be recommended for more than 40 patients a year for practical reasons. Similarly, for 5 HDR compared with 2 LDR fractionations, LDR-3 would be recommended for up to 20 patients per year and HDR for a greater number of patients. Recommendations for other HDR/LDR fractionations and annual number of patients seen can be derived from the model. This recommendation is based on no cost sharing with other sites. Cost sharing was beyond the scope of this analysis, though the principles are similar to the ones used. The model may be adapted to help equipment decision-making for a brachytherapy programme for an individual centre.
Pedicular cleft associated with bilateral pars interarticularis defects and transverse process hypoplasia of a fifth lumbar vertebra
Authors: Kalideen J M , Satyapal K S , Bayat F 
Published: July 2009

Abstract
The rare anomaly of cleft pedicle co-existing with bilateral pars interarticularis defects and ipsilateral transverse process hypoplasia of a lumbar vertebra is described in a 39-year-old male presenting with chronic low backache. The importance of recognizing pedicular clefts as congenital anomalies and distinguishing them from fractures or destructive processes is emphasized, and the relationship of pedicular clefts to hypoplastic or absent pedicles is discussed.
Mesenteric arterial rupture following blunt abdominal trauma: demonstration by computed tomography
Authors: O'Sullivan G , Williams M , Hughes P M 
Published: July 2009

We read with interest the article by Campbell and Zammit-Maempel [1] on the demonstration of mesenteric arterial rupture following blunt abdominal trauma and wish to make the following points.
The management and investigation of major trauma victims is likely to receive increasing prominence in the United Kingdom literature with the institution of major trauma facilities. We should remember, however, that such facilities are well established in the United States, providing excellent data on techniques and findings in major trauma victims [2].
Calulation of radiation induced complication probabilities for brain, liver and kidney, and the use of a reliability model to estimate critical volume fractions
Authors: Olsen D R , Kambestad B K , Kristoffersen D T 
Published: July 2009

Abstract
Radiation induced normal tissue complication probability is calculated for three different organs: brain, liver and kidney. The model applied is a reliability model where the volume effect of the tissue is described by the structural parameter, k, which reflects the architecture of the functional subunits of the organ. The complication probability depends on k, the inactivation probability of the functional subunits (p) and the irradiated volume fraction (n). For partial, homogeneous irradiation of the brain, a k-value close to unity was found, and the respective values for liver and kidney were 0.92 and 0.77. An extension of the reliability model to account for individual inactivation probability of the subunits allows calculation of complication probability for inhomogeneous dose distributions. For the brain, intercomparison of a three-field and a two-field technique demonstrated a small reduction in complication probability for the former at low total doses. At high total doses a minimum complication probability was achieved applying a three-field technique, being three times less than that associated with the two-field technique.
Non-uniform dwell times in line source high dose rate brachytherapy: physical and radiobiological considerations
Authors: Jones B , Tan L T , Freestone G , Bleasdale C , Myint S , Littler J 
Published: July 2009

Abstract
The ability to vary source dwell times in high dose rate (HDR) brachytherapy allows for the use of non-uniform dwell times along a line source. This may have advantages in the radical treatment of tumours depending on individual tumour geometry. This study investigates the potential improvements in local tumour control relative to adjacent normal tissue isoeffects when intratumour source dwell times are increased along the central portion of a line source (technique A) in radiotherapy schedules which include a relatively small component of HDR brachytherapy. Such a technique is predicted to increase the local control for tumours of diameters ranging between 2 cm and 4 cm by up to 11% compared with a technique in which there are uniform dwell times along the line source (technique B). There is no difference in the local control rates for the two techniques when used to treat smaller tumours. Normal tissue doses are also modified by the technique used. Technique A produces higher normal tissue doses at points perpendicular to the centre of the line source and lower doses at points nearer the ends of the line source if the prescription point is not in the central plane of the line source. Alternatively, if the dose is prescribed at a point in the central plane of the line source, the dose at all the normal tissue points are lower when technique A is used.
Quantitative magnetic resonance for assessment of radiation fibrosis after post-mastectomy radiotherapy
Authors: Johansen J , Taagehøj F , Christensen T , Overgaard J , Overgaard M 
Published: July 2009

Abstract
Subcutaneous fibrosis is a serious complication of post-mastectomy radiotherapy with a pronounced influence on skin conditions, shoulder movement and arm oedema. To establish safer radiotherapy schedules, precise evaluation of the tissue damage is required. A feasibility study was performed to asses the value of calculated relaxation times from magnetic resonance (MR) images for quantitative characterization of different degrees of subcutaneous fibrosis after post-mastectomy radiotherapy. A surface coil was applied to the irradiated area, as well as to unirradiated skin, to obtain appropriate MR coronal slices for acquisition of calculated values using a mixed imaging sequence technique. 14 patients with clinically diagnosed subcutaneous fibrosis were examined, 10 of whom had severe fibrosis. The mean T 2 values of the treated and untreated side were 53.0 and 56.7, respectively. A statistically significant decrease of the calculated T 2 values on the treated side was observed. No correlation was found between the clinically assessed fibrosis and the calculated relaxation times. The findings indicate that despite a general decrease of T 2 calculated values, the large variation in the relaxation times restricts the value of MR, as applied in this study, in differentiating between different degrees of fibrosis in normal tissues after radiotherapy.
Traumatic aortic rupture: demonstration by magnetic resonance imaging
Authors: Hughes J P , Ruttley M S T , Musumeci F 
Published: July 2009

Abstract
Traumatic rupture of the aorta is a major cause of morbidity and mortality in rapid deceleration road traffic accidents, with an immediate mortality of 85%. Of the 15% that survive the initial injury, approximately 50% will die within 24 h if left untreated. Prompt diagnosis and early surgical treatment are necessary if such patients are to survive. Aortography is the standard investigation of choice and provides a rapid, sensitive test of aortic rupture. Other modalities, such as plain chest radiography, computed tomography (CT) and ultrasound may also play a role in diagnosis. Magnetic resonance imaging (MRI), with its multi-planar imaging capability, is now widely used for imaging non-traumatic disorders of the aorta. However, its use in traumatic rupture has been limited by difficulties in monitoring and in access to the patient during the scan. We present a patient who survived the initial injury, when the diagnosis of aortic rupture was not suspected, and presented 3 weeks later with chest pain. An MRI scan was feasible as the patient was haemodynamically stable, and it provided an elegant non-invasive means of diagnosis, so that aortography was not necessary in this case. Although aortography is likely to remain the investigation of choice in the acute situation, MRI is a useful alternative in selected cases.
Variations in the radiological management of intussusception: results of a postal survey
Authors: Jewell F M , Roobottom C , Duncan A 
Published: July 2009

Abstract
A survey of the radiological reduction of intussusception in a selection of British hospitals was performed using a questionnaire. Replies were received from radiologists working in 51 district general hospitals and 25 teaching hospitals or specialist paediatric institutions. Most district general hospitals still use barium as the sole method of reduction of intussusception. Most teaching hospitals and specialist paediatric units have changed to a pneumatic method. The contra-indications, details of patient preparation and technical details of each method varied considerably.
Models for estimating the risk of ulcers in the small intestine after localized single or fractionated irradiation
Authors: Scott B R , Langberg C W , Hauer-Jensen M 
Published: July 2009

Abstract
Subacute and chronic ulcerations of the intestinal mucosa are important causes of serious complications following radiation therapy for abdominal or pelvic tumours. We describe dose–response models for estimating the risk of mucosal ulcers in the small intestine after uniform, localized single or fractionated (once-daily) X-ray exposure. The models were fitted to data for ulceration incidence, based on a 26 week post-irradiation follow-up of male Sprague–Dawley rats which received a wide range of single and fractionated once-daily 250 kV X-ray doses to a short loop (partial volume) of transposed, but functionally intact, small intestine. The models presented for single (Weibull (W)) and fractionated (modified Weibull (MW)) exposures of a partial volume of tissue allow estimation of the risk of radiation-induced injury. While the W model is not new, its adaptation to partial volume irradiation and the MW model are. Isoeffect relationships are presented for the uniform fractional dose Ds{i%} associated with an i% (e.g. 0%, 5%, 10%, 50%) risk of intestinal mucosal ulcers as a function of the number of once-daily dose fractions, where Ds{0%} represents the threshold fractional dose. Although the Ds{5%} and Ds{0%} estimates provided for intestinal mucosal ulcers are based on animal data, the ratio Ds{0%}/Ds{5%} and more generally ratios Ds{j%}/Ds{i%} (where i ≠ j), are presumed to apply to humans. The indicated ratios are predicted to be independent of the partial volume irradiated and the number of once-daily dose fractions, and may be independent of radiation quality. Isoeffect equations are also presented that apply to circumstances where different partial volumes within the same reference volume (i.e. the total volume of tissue considered) receive different doses, but the dose within a given partial volume is uniformly distributed. These isoeffect equations provide a means of converting nonuniform dose within a reference volume to uniform isoeffect dose to the total reference volume and may have applications outside the field of radiation therapy (e.g. evaluating effects of non-uniform exposure of the small intestine or skin by a hot particle).
Update on the recommended viewing protocol for FAXIL threshold contrast detail detectability test objects used in television fluoroscopy
Authors: Launders J H , McArdle S , Workman A , Cowen A R 
Published: July 2009

Abstract
The significance of varying the viewing conditions that may affect the perceived threshold contrast of X-ray television fluoroscopy systems has been investigated. Factors investigated include the ambient room lighting and the viewing distance. The purpose of this study is to find the optimum viewing protocol with which to measure the threshold detection index. This is a particular problem when trying to compare the image quality of television fluoroscopy systems in different input field sizes. The results show that the viewing distance makes a significant difference to the perceived threshold contrast, whereas the ambient light conditions make no significant difference. Experienced observers were found to be capable of finding the optimum viewing distance for detecting details of each size, in effect using a flexible viewing distance. This allows the results from different field sizes to be normalized to account for both the magnification and the entrance air kerma rate differences, which in turn allow for a direct comparison of performance in different field sizes.
Low density contrast in upper abdominal computed tomography
Authors: Walker D , Blaquiere R M 
Published: July 2009

Abstract
We describe the use of a fat-based low density oral contrast agent in computed tomography (CT) of the upper abdomen. It has a CT number of –71 Hounsfield units (HU) and allows excellent visualization of the bowel wall and adjacent structures as well as reducing the artefacts seen with iodinated high density contrast.
Current indications for high resolution computed tomography scanning of the lungs
Authors: Padley S , Gleeson F , Flower C D R 
Published: July 2009

Abstract
High resolution computed tomography (HRCT) is an effective technique for demonstrating the lung parenchyma in detail and overcomes many of the inadequacies of chest radiography in the diagnosis of diffuse lung disease. This article reviews the role of HRCT in the management of patients with chronic infiltrative lung disease, occupational lung disease, airways disease and acute and sub-acute lung disease.
Dual contrast magnetic resonance imaging with combined use of positive and negative contrast agent in human hepatocellular carcinoma
Authors: SUTO Y , Shimatani Y 
Published: July 2009

Abstract
Dual contrast magnetic resonance imaging (DCMR) with combined use of a negative contrast medium, chondroitin sulfate iron colloid (CSIC), and a positive contrast medium, Gd-DTPA, was attempted in 20 cases of hepatocellular carcinoma. Spin echo T 1 weighted and T 2 weighted images (T 1WI, T 2WI), and T 1 weighted images 15 min after intravenous injection of Gd-DTPA (0.1 mmol kg−1) were obtained. Within 1 week, these MR studies were repeated within 1 h of intravenous injection of CSIC (23.6 μmol Fe kg−1) under similar conditions. DCMR and the other five imaging techniques were visually evaluated and compared in terms of tumour detectability, tumour spread and qualification of tumours (depiction of inner structure). DCMR was significantly better than Gd-DTPA enhanced T1WI in tumour detectability, and better than Gd-DTPA enhanced T 1WI or CSIC enhanced T 1WI in depicting tumour spread. In the qualification of tumours, DCMR was significantly better than all the other five imaging techniques. None of the patients in this study showed adverse reactions or significant changes in biochemistry. DCMR is an imaging technique which is able to utilize the characteristics of these contrast agents collectively, and exhibits advantages in grasping the inner structure of tumours, especially in hepatocellular carcinoma.
Subjective evaluation of image quality based on images obtained with a breast tissue phantom: comparison with a conventional image quality phantom
Authors: Olsen J B , Sager E M 
Published: July 2009

Abstract
A breast tissue phantom was used for assessment of mammographic image quality. Three images, exposed to give a reference area film density of 1.25 ± 0.03, were obtained for each of five different film/kV combinations. Each of three radiologists carried out a series of three blind readings, in which the 15 films were ranked according to sharpness and contrast. In a similar experiment with a conventional image quality phantom, scores for the visualization of simulated calcifications and contrast–detail performance, and measures for resolution and contrast were obtained. In both experiments, the judgements of the readers were highly consistent, and both the intraobserver and interobserver variabilities were non-significant. No significant differences between the film/kV combinations were found with respect to high-contrast resolution and visualization of the simulated calcifications. The contrast measures obtained with the conventional phantom correlated well with the contrast scores obtained with the breast tissue phantom. The contrast–detail scores obtained with the conventional phantom showed no correlation with the scores obtained with the breast tissue phantom, nor with the contrast measures obtained with the conventional phantom.