bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dosimetric accuracy at low monitor unit settings
Authors: Bomford C. K. 
Published: July 2009

I read with interest the article by Das et al (1991) and appreciate the authors' concern over the accuracy of dosimetry systems at high dose rates and low monitor unit settings.
The purpose of writing this letter is to underline that, in the UK, the accuracy of patients' treatments should not be jeopardized as suggested, in that short exposures on linear accelerators have been deprecated for the past 20 years (HMSO, 1972; DHSS, 1975; NRPB, 1988).
Intrarenal Doppler ultrasound studies in normal and acutely obstructed kidneys
Authors: Rodgers P. M. , Bates J. A. , Irving H. C. 
Published: July 2009

Abstract
Renal ultrasound examinations and intrarenal arterial Doppler studies were performed on 48 patients with normal renal tracts and 20 patients presenting with acute renal colic resulting from ureteric calculus, 14 of whom had urographic evidence of renal obstruction. The mean resistance index (RI) of the Doppler waveforms obtained on the 14 obstructed kidneys (70.4 ± 6.22) was significantly higher than the mean RI of the 96 normal kidneys (62.4 ± 6.43). The mean difference between the RIs of the obstructed kidneys and their contralateral non-obstructed kidneys (8.37 ± 4.43) was also significantly higher than the differences in RI seen between pairs of normal kidneys (2.70 ± 1.71). Five out of 14 obstructed kidneys showed no pelvicalyceal dilatation and could not have been shown to be obstructed on conventional sonography. Four of these five had RI changes suggestive of obstruction and thus 13 of 14 obstructed kidneys would have been identified as obstructed by a combination of Doppler and conventional sonographic findings. 10 of the 14 obstructed kidneys were re-examined after passage of a urinary calculus and nine showed a reduction in the RI of the previously obstructed kidneys. The 10th subsequently required ureterolithotomy.
Dose reduction by the use of erbium filtration in a general radiographic room
Authors: Cranage R. W. , Howard C. J. , Welsh A. D. 
Published: July 2009

Abstract
The conventional aluminium filtration of a general purpose X-ray tube in a district general hospital was replaced by an erbium filter for a 2-month period. The resulting reduction in skin dose was measured for a number of examinations using thermoluminescent dosimetry. The change in effective dose equivalent was calculated from these measurements and compared with previous theoretical estimates. The use of the erbium filter had no effect on radiograph quality. It was concluded that the use of an erbium filter resulted in a worthwhile reduction in radiation dose, and was a cost-effective method of dose reduction.
Magnetic resonance imaging and treatment of an unusual seminoma metastasis occurring in the parasellar region
Authors: Guy R. L. , Mason M. , Van Rensburg L. Janse 
Published: July 2009

Seminoma of the testis is a relatively common tumour in young men and its typical pattern of spread is well documented. We describe an unusual case of a right parasellar seminoma metastasis presenting with partial fifth and sixth cranial nerve palsies. The appearances of the tumour on magnetic resonance imaging (MRI) and the current treatment for metastatic seminoma are discussed.
A 32-year-old man presented with a right testicular mass and underwent a right orchidectomy. Histology showed the testis to be replaced by a combined malignant teratoma undifferentiated and a classical seminoma. Staging investigations showed involvement of right iliac lymph nodes. The patient was treated with five courses of combination chemotherapy with vincristine, methotrexate, cisplatinum and bleomycin alternating with etoposide, actinomycin D and cyclophosphamide (POMB/ ACE), following which he was in complete remission as judged by lymphography.
Book reviews
Authors: Colquhoun I. R. 
Published: July 2009

This is a well presented quality hardback edition of 497 pages. There are copious illustrations, the majority of which are of a high standard together with many useful lists and tables; these features together with the lucid text make this an interesting and enjoyable book.
In the preface the author states his intention to provide an in-depth discussion of the basic principles of neurodiagnosis. As the number and complexity of the available imaging techniques has so rapidly increased over the past few years this is an increasingly difficult task to undertake, especially in less than 500 pages.
Intramuscular myxoma: magnetic resonance features
Authors: Abdelwahab Abrahim Fikry , Kenan Samuel , Hermann George , Lewis Michael M. , Klein Michael J. 
Published: July 2009

Abstract
Magnetic resonance imaging (MRI) was performed in six cases of intramuscular myxoma of the extremities and revealed the following characteristics. All tumours were confined to muscle and had a sharply defined border. All had a signal intensity lower than skeletal muscles on T 1-weighted images and brighter than fat on T 2-weighted images. The signals were homogeneous on both T 1 and T 2-weighted images. This study did not include contrast enhancement. The diagnosis was confirmed by an open biopsy. All tumours were resected with no recurrence. Diagnosis based on these MRI characteristics was incorrect in two cases of intramuscular ganglia and in a case of intramuscular cysticercus cellulose. MRI features of intramuscular myxoma are typical in the majority of cases. Benign intramuscular lesions that contain mainly fluid can mimic intramuscular myxomas.
The ultrasound appearances of intramural bowel gas: the bright ring appearance and the effervescent bowel. A report of three cases
Authors: Bloom Ronald A. , Craciun Eli , Lebensart Pinchus D. , Levy Pavel , Ziv Jacob Bar 
Published: July 2009

Abstract
Bowel necrosis is a serious condition with a very high mortality rate. The earlier the diagnosis is made, the better chance for survival. Ultrasound is a primary imaging technique in the diagnosis of the acute abdomen. Three cases are presented in which bowel wall gas could be demonstrated on ultrasound. In all cases there was computed tomographic and either operative or post-mortem correlation. In each case there was a “bright ring” appearance of the affected bowel when the ultrasound examination was carried out in transverse section. In one case, small bubbles were seen arising from the deep surface of the bowel.
The thread and streak sign of portal vein tumour thrombus demonstrated by colour Doppler imaging
Authors: McBride K. , Masterson J. 
Published: July 2009

The angiographic, computed tomographic (CT) and real-time ultrasound demonstration of portal vein invasion and tumour thrombus is well documented, particularly in association with hepatocellular carcinoma (Gregg et al, 1975; Miller & Thomas, 1979; Freeny, 1980). One sign of portal vein tumour thrombus is the “thread and streak” sign first described angiographically in 1975 (Okuda et al, 1975). In this paper, we describe an unusual case of portal vein tumour thrombus first suspected by colour Doppler imaging (CDI). There have been no previously documented cases to show the thread and streak sign using this technique.
A 73-year-old man presented with a 4-month history of back pain, anorexia, weight loss and dyspnoea. He had a history of left pneumonectomy for squamous cell carcinoma of the bronchus 12 years previously, and a more recent history of drainage of left empyema 9 months earlier.
What is the clinical disadvantage of discarding old radiographs? Survey of patients not re-examined for a long time
Authors: Oyama Y. , Imamura K. , Ashida H. , Nakajima Y. , Itoh T. , Saeki M. , Kikuchi Y. , Matsumoto H. , Ishikawa T. 
Published: July 2009

Abstract
The clinical disadvantage of discarding old radiographs was evaluated in patients who had not been re-examined for more than 8 years after their last radiological examination, 38 772 in total. During the 1 year survey, 158 (0.41%) of them underwent re-examination after a long interval. Retrospective evaluation revealed that in only 12 patients (0.032%) were the old films useful. This survey suggested that the clinical risk of not referring to films more than 8 years old would be less than 0.049%. We consider this acceptable, and have formulated new guidelines of storage of films.
How frequent is chronic lumbar arachnoiditis following intrathecal Myodil?
Authors: Hughes D. G. , Isherwood I. 
Published: July 2009

Abstract
Chronic lumbar arachnoiditis has numerous causes, including the introduction of contrast media into the lumbar subarachnoid space. The oily contrast medium Myodil (iophendylate) is often cited but the true incidence of symptomatic lumbar arachnoiditis due solely to the presence of Myodil is unknown. A retrospective review of 98 patients in whom Myodil was introduced by ventriculography or cisternography, i.e. remote from the lumbar spine, revealed no cases of chronic lumbar arachnoiditis. All patients were monitored closely for periods ranging from 1 to 28 years. We conclude that, in these circumstances, it is rare for Myodil to produce symptomatic arachnoiditis.
The prognostic importance of CT features in primary intracranial lymphoma
Authors: Namasivayam J. , Teasdale E. 
Published: July 2009

Abstract
The correlation of computerized tomography (CT) features with survival of 28 patients with primary intracranial lymphoma was analysed retrospectively. Severe perifocal oedema, periventricular tumours and lesions which were nonhomogenously enhancing or non-enhancing were found to be associated with a poor prognosis. The prognosis when multiple lesions were present was almost the same as that of a solitary lesion (p = 0.95). Ring enhancing lesions had considerably longer survival. Lesions in the frontal region and those close to the meninges, enhancing homogeneously, had a better prognosis.
Transverse geniculate ligament of the knee: appearance and frequency on plain radiographs
Authors: Sintzoff Serge A. , Stallenberg Bernard , Gillard Isabelle , Gevenois Pierre A. , Matos Celso , Struyven Julien 
Published: July 2009

Abstract
The aims of the study were to determine the frequency of visualization of the normal transverse geniculate ligament (TGL) of the knee on lateral plain radiographs with magnetic resonance imaging (MRI) as a reference, and to determine features that make this ligament apparent on plain radiographs. 50 consecutive lateral plain radiographs and sagittal T1-weighted images of corresponding knees were evaluated prospectively. A TGL was considered visualized on plain radiographs when an opacity of soft-tissue density was apparent in the posterior part of the Hoffa's fat pad. The TGL was identified in 29 of the 50 (58%) sagittal MR images; a TGL was observed on the lateral plain radiographs of six patients (12%). Correlation with the MR images showed that, when visualized on plain radiographs, the ligament is at least 3 mm thick and completely surrounded by fat. Our study shows that the TGL is a normal variant that can be recognized frequently on lateral plain radiographs of the knee.
Digital cardiac imaging—the death knell of cineangiography?
Authors: Dyet J. F. , Hartley W. , Cowen A. R. , Aber C. P. 
Published: July 2009

Digital X-ray imaging techniques have achieved wide-spread acclaim in general vascular diagnosis and in the support of interventional procedures. However, in cardiac angiography, acceptability of digital imaging until recently, has been less enthusiastic. To a large extent this has reflected the effectiveness of cine fluorography and the exacting performance standards that it sets to any competing technique. Whereas cine fluorography provides rapid acquisition of dynamic sequences of high (spatio-temporal) fidelty images, the review of these images has to be retrospective and in practice it is necessary to rely heavily on the modest image quality provided by TV fluoroscopy for the on-line evaluation of the procedure.
Early attempts at digital cardiac imaging based upon digital subtraction angiography (DSA) produced results of widely inconsistent quality. This was partly because of the inferior specification of the equipment used at that time. In addition, however, the dynamic nature of the heart itself sets limits to the precision with which subtractive imaging could be performed. Nonsubtractive, or grey-scale, digital imaging on the other hand promised several practical advantages over DSA for cardiac studies, provided that the quality of the images could be enhanced using digital imaging techniques (Rouse et al, 1986).
The recent introduction of extremely fast but economical analogue to digital converters and microprocessors now means that the contest between digital and cine fluorography in cardiac imaging can begin in earnest. Viable digital imaging systems which are custom designed for cardiac applications are now available.
Single- versus dual-energy quantitative computed tomography for spinal densitometry in patients with rheumatoid arthritis
Authors: Laan Roland F. J. M. , van Erning Leon J. Th. O. , Lemmens J. Albert M. , van de Putte Levinus B. A. , Ruijs Sjef H. J. , van Riel Piet L. C. M. 
Published: July 2009

Abstract
Lumbar bone mineral density was measured by both single- and dual-energy quantitative computed tomography in 109 patients with rheumatoid arthritis. The results were corrected for the age-related increase in vertebral fat content by converting them to percentages of expected densities, using sex and energy-level specific regression equations obtained in a normal reference population. The percentages of expected density are approximately 10% lower in the single- than in the dual-energy mode, both in the patients with and without prednisone therapy. This difference is statistically highly significant, and is positively correlated with the duration of the disease and with the degree of radiological joint destruction. The data suggest that the vertebral fat content may be increased in patients with rheumatoid arthritis, as a consequence of disease-dependent mechanisms.
Single energy quantitative computed tomography: the effects of phantom calibration material and kVp on QCT bone densitometry
Authors: Whitehouse R. W. , Adams J. E. 
Published: July 2009

Bone mineral densitometry by quantitative computed tomography (QCT) was introduced in 1976 (Isherwood et al 1976), and is now a clinically established and useful technique. It is usually performed with a reference phantom scanned with the patient. The reference phantom is required to correct for variations that may occur in measured CT numbers due to CT scale drifts or changes in effective beam energy (Cann and Genant 1980). The measured CT number in a region of interest is expressed in mineral density equivalents of phantom reference material.
A saturated solution of dipotassium hydrogen phosphate (K2HPO4) in water has been used in dosimetry as a cortical bone equivalent material for many years (Witt and Cameron, 1969) and dilutions of this material are popular for QCT reference phantoms used in trabecular bone mineral densitometry (Cann and Genant, 1980). Several potential sources of error have been identified with reference phantoms containing aqueous solutions of K2HPO4, including changes in concentration of the solute with time and displacement effects (Rao et al, 1987). These problems have stimulated searches for alternative reference materials, the most popular of which has been calcium hydroxyapatite. This has been regarded as preferable to K2HPO4 as calcium hydroxyapatite is a true constituent of bone. Calcium hydroxyapatite is not water soluble and has to be embedded in a water equivalent plastic. The attenuations of K2HPO4 and calcium hydroxyapatite alter with X-ray energy in similar, but not identical, rates to that of bone (Hubbell, 1969; ICRU, 1989).
Efficiency of a lead-containing tie for radiation protection of the thyroid gland
Authors: Klein Hans-Martin , Stargardt Achim 
Published: July 2009

Abstract
During fluoroscopy the examiner is usually protected by a radiation-reducing body shield, leaving the thyroid unprotected. The fact that the thyroid is located in a region of the neck usually covered by the shirt collar led to the idea of designing a tie with lead core, providing easy and “decorative” reduction of the radiation dose. Sonographic examinations were carried out in 20 volunteers (10 men, 10 women) to determine the size of the gland and its coverage by such a tie. The reduction of the surface and organ dose was assessed using film dosimetry with scattered radiation, the body of the examiner being simulated by an Alderson phantom. On average 88% of the thyroid gland surface area was covered. Surface dose was reduced to 1%, and organ dose to 10% of the value without the protection tie.
Effect of diatrizoate on the function of the isolated perfused rat kidney
Authors: Brownd P. , Haylor J. , Morcos S. K. , Cope G. H. , El Nahas A. M. 
Published: July 2009

Abstract
The mechanism of the nephrotoxicity of water-soluble contrast media (WSCM) remains ill denned. We have studied the effect of diatrizoate on the isolated perfused rat kidney (IPRK). Emphasis was on the effect of low- and high-dose diatrizoate on glomerular filtration rate (GFR), renal perfusate flow (RPF), fractional excretion of albumin (FE Alb) and fractional reabsorption of sodium (FR Na). The addition of diatrizoate to the IPRK led to a dose-dependent biphasic change in RPF and GFR characterized by an initial transient increase followed by a marked and sustained decrease. Diatrizoate induced a diuresis and a parallel increase in urinary sodium excretion (fall of FR Na). FE Alb was also increased in kidneys exposed to diatrizoate. Electron microscopy of a control kidney showed preservation of cellular architecture, which contrasted with the observed cytoplasmic vacuolation of proximal tubular cells after perfusion with diatrizoate. This study confirms a direct effect of WSCM on the function of the IPRK. In this experimental model, diatrizoate reproduces the effects observed in vivo on GFR and renal perfusion.
Dural venous sinus thrombosis following myelography: demonstration by magnetic resonance imaging
Authors: Hartley R. W. J. , Jackson A. , Cooke R. S. 
Published: July 2009

Headache is a common complication of myelography, occurring in approximately 30% of cases (Wilkinson & Sellar, 1991). The headaches may be severe and are frequently postural in nature. We present a case in which a severe post-myelographic headache progressed over a period of six weeks. The development of fundal haemorrhages with visual impairment prompted investigation by magnetic resonance imaging (MRI) which demonstrated thrombosis of the right transverse sinus. Anticoagulant therapy led to prompt relief of symptoms and improvement of visual acuity.
A 51-year-old man presented to another hospital with three days of severe low back pain and right-sided sciatica. Initial examination demonstrated reduced straight leg raising on the right but no other abnormality. Initial treatment with seven days bed rest resulted in no improvement and a lumbar myelogram was performed using iohexol (Omnipaque, 240mg/ml, Nycomed Ltd). Myelography demonstrated no evidence of significant abnormality and the patient's symptoms resolved spontaneously.
Uptake of technetium-99m methylene diphosphonate by a pulmonary hamartoma/mesenchymoma
Authors: Burke W , Rubens M B 
Published: July 2009

Pulmonary hamartomas (or mesenchymomas) are benign developmental abnormalities of the lung, and are usually discovered as an incidental finding on a chest radiograph. Some exhibit characteristic “popcorn” calcification that may be recognized on plain chest radiography or standard tomography (Bateson et al, 1960), but computed tomography (CT) has been shown to be more sensitive in detecting calcification (Siegelman et al, 1980).
Bone scanning using technetium-99m methylene diphosphonate (99Tcm MDP), a bone-seeking radiopharmaceutical, provides information that reflects skeletal metabolic activity. We report a case of pulmonary hamartoma in which a carcinoma developed in the contralateral lung. In the course of investigating the patient a bone scan was performed and radioisotope uptake by the hamartoma was observed. As far as we are aware this has not been described previously in a pulmonary hamartoma.
The dose-fractionation sensitivity of the kidney; assessment of viable tubule cross-sections at 19 months after X irradiation
Authors: Jen Y-M , Hendry J H 
Published: July 2009

Abstract
The formation of viable tubule cross-sections was assessed in histological sections of murine kidneys at 19 months after fractionated bilateral X-ray doses with 12 h intervals between fractions. The data were analysed using the linear-quadratic model which provides values of α and β characterizing the slope of the dose-response curve, and the ratio of α and β indicative of the sparing effect of dose fractionation. The tubule data were characterized by α = 0.057 ± 0.009 Gy-1, β = 0.011 ± 0.001 Gy-2, α/β = 5.0 ± 0.9 Gy. Also, the number of cells (per focus region of the nephron) calculated as being capable of producing a viable focus was 2.5 ± 0.5, which was confirmed using a separate two-dose approach (2.1 ± 0.3). Together with other data, of the order of 1000 regenerative cells per nephron (104 total cells) can be deduced. The values of the fractionation sensitivity parameters are similar to values measured previously for cells taken from irradiated kidneys up to a year after irradiation and forming colonies in primary culture, and also similar to values assessed using various functional measures of kidney injury.
Hair raising artifacts in magnetic resonance imaging
Authors: Williamson V C 
Published: July 2009

A 44-year-old shot blaster from Camel Lairds ship yard was referred to the neurology outpatients clinic with a history of episodes of diplopia and ptosis. These had been occurring over the past 7 years and all had resolved fully. In addition, he had had an episode of weakness in the left leg when aged 8 years old. This had lasted for a few weeks before resolving.
In view of the above history, demyelinating disease was considered, and a magnetic resonance (MR) scan requested. Images were obtained on a General Electric Signa 1.5 Tesla scanner using spin-echo sequences. A T 1weighted (TR = 600 ms, TE = 30 ms) sagittal series, and an axial proton density and T2 weighted sequence (TR = 2000 ms, with dual echoes at 20 ms and 80 ms) were performed.
Comparison of various film densitometers
Authors: Burch A , Goodman D A , Hill S J , Law J , Robinson A , Underwood A C 
Published: July 2009

Quality control techniques are increasingly being applied in general radiography and particularly in mammography. A densitometer is an important basic tool for quality control measurements, and may be used for checking film processor performance (in conjunction with a sensitometer) and for measuring optical densities at test points on a radiograph of an image quality phantom (BIR, 1988; IPSM, 1989). Incorrect calibration or drift of such an instrument could give a misleading impression of the performance of the imaging system when performing comparisons with colleagues. The purpose of the present work was to establish whether differences between instruments are likely to be a significant source of error.
In a quality control programme, all measuring equipment should be calibrated at a frequency that may be advised by the manufacturer; in the absence of such advice, this would typically be on an annual basis. The densitometers discussed here were not calibrated especially for the study, except where this was a part of the routine method of use.
A test strip was produced, having a range of optical densities, for circulation to the authors. The strip was produced by exposing a Kodak MinRE mammography film to a nine-step optical sensitometer (“QA Sensi-Densitometer” Model SDM, MIC Medical Ltd). This resulted in nine areas of the film, each roughly 1 cm square, with various densities in the range approximately 0.2–3.3.