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[en] Low energy photons (1150 keV) are essential for obtaining high quality X-ray radiographs, These photons are usually produced in the accelerator target, but are effectively absorbed by the flattening filter and. at least partially, by the target itself An experimental proof is presented for the existence of low-energy photons in the un flattened X-ray beam produced by a 10 MeV electron beam normally incident on the thinner of the two existing ports of the all-Cu radiotherapeutic target of a Clinac 18 (Varian Associates) linear accelerator. A number of one-shot absorption measurements were carried out with 12 foils of Pb- absorbers with thicknesses varying from 0.25 to 3 mm in steps of 0.25 mm arranged symmetrically around the central axis on a 7,2 cm radius circumference, A Kodak ECL film screen-cassette combination was used as a detector in the absorption measurements, in which optical density was measured as a function of the thickness of the Pb absorbers. Two sets of absorption measurements were carried out: the first one with the Clinac 18 10MV un flattened beam and the second one with the Clinac 18 10MV therapeutic flattened beam, There is a striking difference between the two sets the optical density versus Pb-absorber thickness curve shows sharp increase in optical density at small absorber thicknesses in the case of the un flattened 10MV X-ray beam as compared with a gently sloping dependence in the case of the 6MV therapeutic beam. A semi-quantitative assessment of the low- energy photon contribution to the whole optical density/contrast is presented. A 0.25 mm thick Pb absorber intercepting the IOMV un flattened X-ray beam eliminates almost totally the sharp peak in the optical density curve at small Pb-absorber thicknesses. This constitutes another evidence for the existence of low-energy photons (1150 keV) in the un flattened 10MV beam from the Cu therapeutic target
[en] The diagnostic value of a intra oral film is related to projecting technic and interpretation. The intra-oral film is a single plane representation of a three dimensional object, therefore superimposition is inevitably present. The purpose of this article is to show how foreign objects in the jaw may be localized. The author used double exposure technic, that are changed angulation of vertical or horizontal to one film. The obtained results are as follow: 1. In the upper anterior region, the moving distance of the labially impacted reference object was greater than that of the palatally impacted one. 2. In the upper molar region, the moving distance of the mesiobuccal root apex was the greatest and that of palatal root apex was the shortest. 3. In the lower molar region, the change of the alveolar bone level in the buccal side was greater than that of lingual side.
[en] This study was conducted to understand for the diagnostic discordance of bone mineral density(BMD) in DEXA(Dual Energy X-ray Absorptiometry). And the diagnostic difference between lumbar spine and femur neck, forearm was evaluated using T-score. We studied 220 females measured BMD on lumbar spine, and femur neck, forearm including ward's triangle and ultra digital(UD). We were distinguished T-score into normal, osteopenia, osteoporosis(WHO classification) and evaluated discordance rate according to age and degree of bone loss. Correlation analysis and chi-square test between L-spine, L-4, femur neck, Ward, Forearm, UD were carried out. In the lumbar spine, the number of normal were in 57(25.9%), osteopenia in 86(39.1%), osteoporosis in 77(35.0%). In the L-4 and ward's triangle, the number of osteoporosis were in 78(35.5%), in 126(57.3%). There was significant correlation between lumbar, femur neck and forearm BMD in all cases. The discordance of BMD between lumbar and femur were 57%, lumbar and forearm 43%, forearm and femur 51%. The discordance rates of normal, osteopenic, osteoporotic groups were 39%, 64%, 43%, respectively, showing the highest discordance rate in osteopenia patients. In normal group of lumbar spine, the discordance rate was 25%, 23%, 11%, 65%, 86% in 30', 40', 50', 60', 70', respectively. In osteopenia, osteoporosis group of lumbar spine, the discordance rate was 62%, 55%, 36%, 20%, 9% in 30', 40', 50', 60', 70', respectively. It was different of the results of BMD with lumbar, femur and forearm site. The discordance rate was decreased with age in osteopenia, osteoporosis lumbar spine. In osteopenia group, the discordance rate was the highest. So, it is necessary that the BMD of lumbar, femur neck and forearm should be checked.
[en] To evaluate the diagnostic accuracy of a new ultrasound (US) classification system for differentiating between benign and malignant solid thyroid nodules. In this study, we enrolled 191 consecutive patients who received real-time US and subsequent US diagnoses for solid thyroid nodules, and underwent US-guided fine-needle aspiration. Each thyroid nodule was prospectively classified into 1 of 5 diagnostic categories by real-time US: 'malignant,' 'suspicious for malignancy,' 'borderline,' 'probably benign,' and 'benign'. We evaluated the diagnostic accuracy of thyroid US and the cut-off US criteria by comparing the US diagnoses of thyroid nodules with cytopathologic results. Of the 191 solid nodules, 103 were subjected to thyroid surgery. US categories for these 191 nodules were malignant (n = 52), suspicious for malignancy (n = 16), borderline (n = 23), probably benign (n 18), and benign (n = 82). A receiver-operating characteristic curve analysis revealed that the US diagnosis for solid thyroid nodules using the 5-category US classification system was very good. The sensitivity, specificity, positive and negative predictive values, and accuracy of US diagnosis were 86%, 95%, 91%, 92%, and 92%, respectively, when benign, probably benign, and borderline categories were collectively classified as benign (negative). The diagnostic accuracy of thyroid US for solid thyroid nodules is high when the above-mentioned US classification system is applied.
[en] The purpose of this study was to decide the diagnostic value of transmaxillary and transcranial projection in the evaluation of mandibular condyles. Five dry skulls with intact anatomic structure were selected for this study and the artificial osteophytes were attached to 9 different areas of the mandibular condyle. Ninety transcranial and forty-five transmaxillary radiographs were taken and then the radiographs were evaluated three times. The results were as follows: In transcranial radiographs, superocentral osteophyte was easily observed in closing state than in opening state (p<0.05). But there were no significant differences in other locations (p>0.05). The osteophytes on the medial and central portion were easily observed at the transmaxillary projection than transcranial projection (p<0.05), but there was no significant difference on the lateral portion(p>0.05). The osteophytes on the superior (p<0.01) and posterior (p<0.01) portion were easily observed at the transmaxillary projection than transcranial projection, but there was no significant difference on the anterior portion(p>0.05). The more laterally located osteophytes (p<0.01) at the transcranial projections were easily observed. The more posteriorly located osteophytes (P<0.05) at the transmaxillary projections were easily observed.
[en] A pratical method to determine the activity of kinase will be developed. The method will be used to construct a miniaturized analysis for the determination of kinase activity based on RI system. We fabricate miniaturized kinase assay system in a COC (Cyclo Olefin Copolymer) microfluidic chip. The demonstrated strategy demonstrates the usefulness of the microchips for performing enzymatic assays for which leads to multitude of kinase reaction simultaneously
[en] The aim of this study was to establish the diagnostic criteria of normal parotid glands in adults revealing the anatomical shape, its variations and the positional relationships of the gland. Materials included 96 lateral and anterior-posterior sialograms of selected person from 23 to 28 years of age. Results were as follows: 1. The average length and lateral displacement of main duct was 48.43 mm and 16.88 mm. The mean lumen diameter of that was 0.91 mm in distal end and 1.40 mm in hilar end in parotid glands. 2. The average angle of main duct to the inferior border of mandib was 34.32 degree. In configurations of main duct, modified curvilinear type was most prevalent and followed by curvilinear, reverse sigmoid, sigmoid type. 3. The mean caliber of parotid gland was the longest in superior-inferior. 4. The interlobar ducts showed relatively well defined in all cases, its average number was 5.72. Arrangement of these ducts showed at random. Accessory lobe showed 87.5% in the all cases, its average number was 1.7. 5. There were no difference between the well and poorly defined acinar fillings in the glandular parenchyme. 6. There were no differences between right and left parotid glands in size and shape of main duct and parenchymal portion, but there were great variations in each individuals.
[en] Over the past decade, women's health clinicians have witnessed a shift of the paradigm for the approach to prenatal screening for chromosomal abnormalities. From an emphasis on age-based invasive diagnostic tests, women are now being offered a variety of noninvasive screening tests. Although there is exciting research and innovation in the field of noninvasive testing for fetal aneuploidy, there are currently two tests, and both are invasive, that are used in a routine manner to determine the presence of fetal aneuploidy: chorionic villous sampling and amniocentesis. The aim of this review was to investigate the effectiveness of prenatal sonography, including first trimester nuchal translucency screening and second trimester genetic sonography, for obtaining valid chromosomal abnormality screening test results
[en] The main role of fine needle aspiration cytology (FNAC) lies in differentiating between a malignant and benign thyroid nodule. It greatly influences the treatment decision. The current study was undertaken to evaluate the cytology–histopathology correlation and to analyze the cause of diagnostic errors with an eventual aim to improve diagnostic accuracy. Materials and Methods This is a retrospective study comparing cytology and corresponding histopathology report in 724 thyroid cases. The statistical analysis included false positive rate, false negative rate, sensitivity, specificity, positive predictive value, negative predictive value and accuracy. Results On cytological examination, 635/724 were reported as benign, 68 malignant and 21 suspicious. On histopathological examination, 626/635 cases were confirmed as benign but there were 9 discordant cases. Among the other cases histopathology diagnosis of malignancy matched in 66/68 and 11/21 cases. Diagnosis correlated in 703/724 cases (97%) [p < 0.001]. False positive and false negative rates were 1.9% and 10.5%, respectively. The sensitivity and specificity were 89.5% and 98%, respectively. The positive predictive value was 84.6% and negative predictive value was 98.6%. Accuracy of FNA was 97%. Conclusion In spite of high accuracy of FNAC in differentiating between a benign and malignant lesion, certain pitfalls should be kept in mind. The common false negative diagnoses were follicular pattern cases which constitute a ‘gray zone’, cystic papillary thyroid carcinoma (PTC) and papillary micro carcinoma. The reason for false positive diagnoses was the occurrence of nuclear features characteristic of PTC in other thyroid lesions. Awareness of pathologist regarding these pitfalls can minimize false negative/positive diagnoses