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J Kalef-Ezra

Publications and source records attributed to J Kalef-Ezra.

At least 19 recordsLinked to original sources
PubMed2006

Multi-detector row CT urography on a 16-row CT scanner in the evaluation of urothelial tumors.

The purpose of this study was to assess the role of multi-detector row CT urography (MDCTU), on a 16-row CT scanner in the evaluation of patients with painless hematuria, with emphasis placed in the detection of urothelial tumors. We retrospectively reviewed the MDCT urographies of 75 patients, referred for painless hematuria. The CT protocol included unenhanced images, obtained with a detector configuration of 16x1.5 mm and pitch of 1.2, nephrographic and excretory-phase images, obtained with a detector collimation of 16x0.75 mm and pitch of 1.2. Axial and coronal reformatted images were evaluated. Three-dimensional reformation of the excretory-phase images was performed using the volume-rendering technique. The standard of reference included clinical and imaging follow-up, cystoscopic, surgical and histologic findings. In 55 (73%) of 75 patients, the cause of hematuria was identified on MDCTU; the most common cause was urothelial cancer, including seven tumors with a diameter equal or smaller than 0.5 cm in diameter. Sixteen-row MDCTU provided satisfactory results in the investigation of patients with painless hematuria. The main advantage of the technique is its ability to detect uroepithelial malignancies.

Adult↗
PubMed2005

Patient and personnel dosimetry in endovascular radiotherapy with 90Sr/90Y sources.

Endovascular brachytherapy (EVBT) is an established treatment to reduce the probability of restenosis after a percutaneous coronary intervention. The purpose of this study was to assess (1) the manufacturer's stated dosimetric data for (90)Sr/(90)Y source trains to be used in EVBT and (2) the procedure-related radiation burden. The radiation fields in water around six (90)Sr/(90)Y source trains were studied using phantoms made of 'solid water' and MD55-2 radiochromic films. The water equivalence of the phantom material was tested by applying quantitative computed tomography. Thermoluminescence dosemeters were used to assess personal radiation burden and crosscheck the dose distribution along the source trains. Technical failure was observed in one source train and this train was excluded from analysis. The measured dose rate in water at 2 mm radial distance was on average 8% higher than the manufacture's stated value (range of measured to stated values 1.05--1.15). The dose rate decreased exponentially with radial distance between 2 and 6 mm. The dose rate in contact with the source viewing window of the delivery devices ranged between 0.5 and 7.5 mGy h(-1). Low-energy photons were the main contributors to personal dose.

Blood Vessel Prosthesis↗
PubMed2004

Prompt-gamma neutron activation analysis facility for in vivo body composition studies in small animals.

The design, calibration, dosimetry and performance evaluation of a prompt-gamma neutron activation analysis facility for in vivo body composition studies in small animals (i.e. rats or rabbits) is discussed. The system design was guided by Monte Carlo transport calculations using MCNP-4C code. A system was built and performance evaluation was made using a 185-GBq Pu-Be neutron source. Prompt-gamma rays produced by neutron capture reactions were detected by a combination of a NaI(Tl) scintillation and a HPGe semiconductor detectors. Nitrogen and chlorine were quantified by analysis of the 10.83-MeV and 6.11-MeV peaks, respectively. Appropriate corrections for the animal body size were determined. The facility described allows the in vivo determination of protein and extracellular space in sets of experimental animals.

Animals↗
PubMed2004

Computed tomographic virtual cystoscopy for the detection of urinary bladder neoplasms.

OBJECTIVE: To evaluate the role of computed tomographic virtual cystoscopy (CTVC) in the detection of bladder neoplasms and to compare CTVC at conventional and reduced milliAmperes-second (mAs) settings. METHODS: Twenty-four patients with known bladder neoplasms from previous conventional cystoscopy were examined with CTVC. The urinary bladder was insufflated with room air and helical CT data were obtained. Virtual images were created using volume rendering algorithms. In eight patients we used both regular (240) and reduced (70) mAs values. The lesions were recorded on transverse tomographic slices and virtual images and compared with conventional cystoscopy, operative and pathology results. RESULTS: All bladder lesions (30) seen on conventional cystoscopy were demonstrated with CTVC. Two lesions detected on imaging studies and subsequently found at operation were not seen on conventional cystoscopy. In a third case of a neobladder, conventional cystoscopy was impossible due to neoplastic involvement of the penis. In all cases the lesions were equally conspicuous with conventional and low mAs values. CONCLUSIONS: Computed tomographic virtual cystoscopy is a minimally invasive technique that can provide comprehensive information about urinary bladder tumors. Furthermore, low mAs studies are equally effective for the examination of such patients.

Aged↗
PubMed2001

Dosimetry with radiochromic films: a document scanner technique, neutron response, applications.

The possibility of reading radiochromic films by the employment of a document scanner and associated software was explored. Dosimetric characteristics, such as the sensitivity of the technique, reproducibility in dose assessment, minimum detectable dose, film uniformity, OD variation with time, variation of OD due to multiple scans, polarity of the analyzing light, fast neutron response and thermal neutron yield were investigated. The technique was used to measure dose distributions in stereotactic radiotherapy, orthovoltage treatment and neutron capture therapy.

Humans↗
PubMed2001

Response of avian embryonic brain to spatially segmented x-ray microbeams.

Duck embryo was studied as a model for assessing the effects of microbeam radiation therapy (MRT) on the human infant brain. Because of the high risk of radiation-induced disruption of the developmental process in the immature brain, conventional wide-beam radiotherapy of brain tumors is seldom carried out in infants under the age of three. Other types of treatment for pediatric brain tumors are frequently ineffective. Recent findings from studies in Grenoble on the brain of suckling rats indicate that MRT could be of benefit for the treatment of early childhood tumors. In our studies, duck embryos were irradiated at 3-4 days prior to hatching. Irradiation was carried out using a single exposure of synchrotron-generated X-rays, either in the form of parallel microplanar beams (microbeams), or as non-segmented broad beam. The individual microplanar beams had a width of 27 microm and height of 11 mm, and a center-to-center spacing of 100 microm. Doses to the exposed areas of embryo brain were 40, 80, 160 and 450 Gy (in-slice dose) for the microbeam, and 6, 12 and 18 Gy for the broad beam. The biological end point employed in the study was ataxia. This neurological symptom of radiation damage to the brain developed within 75 days of hatching. Histopathological analysis of brain tissue did not reveal any radiation induced lesions for microbeam doses of 40-160 Gy (in-slice), although some incidences of ataxia were observed in that dose group. However, severe brain lesions did occur in animals in the 450 Gy microbeam dose groups, and mild lesions in the 18 Gy broad beam dose group. These results indicate that embryonic duck brain has an appreciably higher tolerance to the microbeam modality, as compared to the broad beam modality. When the microbeam dose was normalized to the full volume of the irradiated tissue. i.e., the dose averaged over microbeams and the space between the microbeams, brain tolerance was estimated to be about three times higher to microbeam irradiation as compared with broad beam irradiation.

Animals↗
PubMed2000

Blueberry juice used per os in upper abdominal MR imaging: composition and initial clinical data.

The aim of this study was to evaluate the use of a commercially available blueberry juice (BJ) both as a positive and negative oral contrast agent and to present the exact contents of paramagnetic ions. The concentration of Mn and Fe were determined in tinned myrtilles in syrup (atomic absorption). Nine healthy volunteers and 12 patients (age range 20-65 years) were examined using a 1-T MR scanner before and after per os administration of 430 ml of BJ. A qualitative analysis of signal alterations in the stomach, duodenum, and proximal small intestine was performed. In addition, a quantitative analysis was assessed in terms of signal-to-noise ratio calculation. The mean concentration (x +/- SD) of the ions found in the content of the three cans were 3.3 +/- 0.4 microg/g for iron and 20.6 +/- 2.6 microg/g for manganese. Based on the qualitative evaluation, signal alteration on T1-weighted images after administration of BJ was statistically significant in the stomach and duodenum, but not in the proximal small bowel. Signal alteration on T2-weighted images was not statistically significant in any part of the gastrointestinal tract. The quantitative analysis of the T1- and T2 shortening showed that BJ is efficient with only T1-weighted sequences, and this applied to the stomach, duodenum, and proximal small bowl. Blueberry juice can be used as an oral contrast agent in upper abdominal MR for T1-weighted imaging.

Administration, Oral↗
PubMed2000

A phantom for dosimetric characterization of small radiation fields: design and use.

An acrylic phantom was designed and constructed for the acquisition and verification of basic dosimetric data of narrow fields in stereotactic radiotherapy/radiosurgery (SRT/SRS) using thermoluminescent (TL) dosimetry. An array of holes to accommodate up to 426 dosimeters was used to allow the assessment of dose distribution in circular fields with a 1-mm spatial dose resolution with minimal field perturbation. It was found experimentally that there must be a minimum gap of 1 mm between neighboring dosimeters in 6-MV photon fields. Most of the dosimetric characteristics of a 6-MV x-ray SRS/SRT unit assessed using TL dosimetry and ion chamber dosimetry were in good agreement when the longitudinal axis of the chamber was parallel to the central beam axis. TL dosimetry showed that the penumbra width increased with increasing collimator aperture. The low cost of the phantom and the widespread use and familiarity of TL dosimetry in radiotherapy departments offer a significant advantage in the use of the proposed methodology.

Equipment Design↗
PubMed1999

CT measurement of lung density.

PURPOSE: The aim of this study was to obtain more accurate data on the electron density of the lungs in healthy subjects and to determine the factors that influence this value. MATERIAL AND METHODS: Single kVp quantitative CT was applied in 130 normal adults (61 men and 69 women) to study the electron density of the lung. RESULTS: The electron density of the lung in men was lower than that in women. In contrast, the area designated as lung in men was larger than that in women. The mean electron density decreased with increasing age in men, but not in women. The following parameters were not found to influence lung electron density: body mass, body height, smoking habits, and right or left lung. The electron density of the lung medial to the thoracic wall and close to the breast was lower than the density in the entire lung parenchyma. CONCLUSION: Quantitative CT provided the means to study noninvasively the electron density of the lung and the factors that influence this value.

Absorptiometry, Photon↗
PubMed1999

The effects of boron neutron capture irradiation on oral mucosa: evaluation using a rat tongue model.

The ventral surface of the tongue of male Fisher 344 rats was used to evaluate the response of oral mucosa to boron neutron capture irradiation. Three hours after i.p. injection of 700 mg/kg of the boron delivery agent p-boronophenylalanine (BPA), the boron concentrations in blood and tongue mucosal epithelium were approximately 21 and 23 microgram (10)B/g, respectively. The doses required to produce a 50% incidence of ulceration with X rays, the Brookhaven Medical Research Reactor thermal neutron beam alone, or the thermal neutron beam in the presence of BPA were 13.4 +/- 0.2, 4. 2 +/- 0.1, and 3.0 +/- 0.1 Gy, respectively. Ulceration of the tongue was evident by 6 to 7 days after irradiation, irrespective of the irradiation modality; healing was related to dose and was relatively rapid (</=19 days). Compared to 100 kVp X rays, the relative biological effectiveness factors were 3.2 for the thermal neutron beam and 4.9 for the products of the boron neutron capture reaction, (10)B(n,alpha)(7)Li. Oral mucosa is highly sensitive to BPA-mediated BNC irradiation and could be a dose-limiting normal tissue in BNCT of brain tumors, or if BPA-based BNCT is applied to the treatment of head and neck tumors.

Animals↗
PubMed1999

A case report on two primary malignancies of the ovary and kidney.

Multiple primary malignant tumors in the same patient are very rare. Moreover, cases with primary ovarian and renal cell carcinoma in the same patient is an extremely rare phenomenon. In this report, a case with these two primaries is described. Concomitantly, some data suggesting a relationship of these primaries with the hypothesis of hormone dependency of renal cell carcinoma is presented.

Adenocarcinoma, Clear Cell↗
PubMed1995

Bone minerals in beta-thalassemia minor.

Homozygous beta-thalassemia is a severe hereditary disorder associated with osteopenia. Recently it was suggested that thalassemia minor may be a risk factor for osteoporosis. The purpose of the present study was to investigate this suggestion. Bone mineral status was assessed in 22 premenopausal women and 21 men with beta-thalassemia minor. In vivo neutron activation analysis was applied to measure hand-bone phosphorus (HBP), single-photon absorptiometry to measure forearm bone mineral content (BMC), and dual-energy X-ray absorptiometry to measure spinal bone mineral density (BMD). Comparison of the HBP, BMC, and BMD values with those of sex- and age-matched healthy subjects without the beta-thalassemia trait failed to indicate a statistically significant difference for either sex group. Concerning the biochemical markers of bone metabolism that were studied (serum calcium, phosphate, alkaline phosphatase, osteocalcin, and parathyroid hormone, and 3-h fasting urine calcium-to-urine creatinine ratio) no difference was observed between the study subjects and matched controls. In conclusion, the present study showed that subjects with beta-thalassemia minor are not at risk for osteoporosis.

Absorptiometry, Photon↗
PubMed1994

Evaluation of six tumor markers in patients with carcinoma of unknown primary.

We have retrospectively evaluated six serum tumor markers in 85 patients with carcinoma of unknown primary. The serum levels of carcinoembryonic antigen (CEA), CA 19-9, CA 15-3, CA 125, beta-chorionic gonadotropin (beta-HCG) and alpha-fetoprotein (AFP) were related with the histological pattern (undifferentiated carcinoma or adenocarcinoma), the number and the site of metastases, as well as the response to chemotherapy and the patients' survival. More than 40% of the patients had increased serum levels of all six tumor markers, except of AFP which was found to be increased in only 17% of them. Increased levels of CA 19-9 were related to metastatic adenocarcinoma, whereas CA 19-9 and CA 15-3 had a relationship with more advanced disease. Patients with liver involvement had higher mean levels of CEA and CA 19-9 as compared to those with nodal disease. None of these markers was found to have a predictive value for response to chemotherapy or survival. Although the present study has a retrospective nature, it allows us to conclude that patients with CUP have a nonspecific over-expression of the above serum tumor markers and that routine use of these markers does not offer any diagnostic or prognostic assistance.

Adenocarcinoma↗
PubMed1992

New evidence that tamoxifen does not induce osteoporosis: a nuclear activation analysis and absorptiometry study.

The possibility of increased risk for osteoporosis in breast cancer patients treated with tamoxifen was investigated. 26 patients aged 41-65 years without skeletal metastases were studied. All patients were treated with 20 mg/d tamoxifen for a mean time of 22 months. The data obtained by in vivo neutron activation analysis of the phosphorus content in hands, were supplemented with data obtained by single photon absorptiometry in the forearm and radiographic morphometry. Comparison of the data with that of age and sex matched normal controls showed that breast cancer patients treated with tamoxifen are not prone to osteoporosis.

Absorptiometry, Photon↗
PubMed1991

Limitations of quantitative CT in corticosteroid induced osteopenia.

Single energy spectrum quantitative CT (SES-QCT) was applied for the assessment of the trabecular bone mineral status in patients under long-term corticosteroid treatment. Seventeen renal graft recipients (RGR) and 12 patients receiving corticosteroid treatment for collagen disease were studied. A reduction of about 40% in the spinal trabecular bone density relative to matched controls was found, associated with the corticosteroid administration. Repeated measurements showed significant reduction in density 4 months after transplantation, and an increase in density after graft rejection. Radiologic or clinical evidence of osteopenia in the spine was not found. Other noninvasive techniques, applied in the upper extremities of the RGR, showed only minor bone reduction compared to controls. The findings of the present study suggest that adipose tissue deposition in the spinal trabeculae can introduce errors in the measurements. Therefore, SES-QCT should not be applied during corticosteroid therapy.

Adult↗
PubMed1990

In vitro determination of uptake, retention, distribution, biological efficacy, and toxicity of boronated compounds for neutron capture therapy: a comparison of porphyrins with sulfhydryl boron hydrides.

A major problem remaining in the evaluation of boronated compounds for neutron capture therapy (NCT) is the need to know the intra- or extracellular microdistribution of boron. This is a consequence of the short range of the 10B(n,alpha)7Li reaction products (approximately 10 microns), such that biological efficacy is dependent upon intracellular distribution. In particular, if boron location is predominantly extracellular, a significant reduction in efficacy would be expected. The in vitro procedure described here was developed mainly to provide information regarding the intra- and extracellular location and concentration of boron. However, use of the technique also allows the measurement of compound uptake and retention (binding) and the determination of biological efficacy by the evaluation of survival curves obtained following irradiation with thermal neutrons. Comparison is made to results obtained with boric acid (H3(10)BO3) and to results calculated for various boron distributions. Concomitantly, an indication of compound toxicity can be obtained from the plating efficiency of unirradiated control cells. Currently, most investigators utilize in vivo systems for testing and evaluating boron uptake from various carrier molecules. Given the large number of boron compounds being synthesized and needing evaluation as to their usefulness for NCT, the in vitro technique described here is simple and advantageous for initial compound screening. In addition to sparing animal lives, it is both time and cost effective and utilizes much smaller quantities of test compound than are required for an in vivo assay. A boronated porphyrin (BOPP) evaluated by the above procedure shows an uptake and retention approximately 20 times that of sulfhydryl boron hydride monomer (BSH); the latter compound is currently being used clinically for NCT in Japan and is anticipated for use in clinical trials in the United States. If the advantages demonstrated by BOPP in these in vitro studies are validated in animal experiments, BOPP should be considered for clinical application.

Animals↗