PURPOSE: The aim of this study was to assess the validity of standard deviation of gray scale histogram in digital subtraction radiography as a test parameter for superimposition error. MATERIALS AND METHODS: Twenty periapical radiographs used baseline images were copied to exclude the influence of exposure geomety and contrast differences. These subsequent images were displaced by 0.1-0.5 mm in the x-, y- and xy-directions, rotated by 0.5-3o and distorted by angular contraction of 1-5o in x- and y-axis before subtraction. Pearson correlation coefficients(r) were calculated between the standard deviation of gray levels in the subtracted image and misplacement and paired t-tests were performed to compare standard deviations. RESULTS: Linear displacement showed high correlation coefficients of 0.997, 0.997 and 0.995 in x-, y- and xy-axis respectively. Statistically significant different standard deviation existed among all linearly displaced groups(p<0.05). Relatively low correlation coefficients of 0.982 and 0.959 in x- and y-axis distortion were demonstrated. The standard deviations between the two distortion groups were statistically significantly different(p<0.05). CONCLUSION: Standard deviation of gray level distribution in digital subtraction images is satisfactory but not perfect similarity measure to assess superimposition errors.
Radiography*

No abstract available.
Radiography*

The purpose of this study is to evaluate the cephalometric reproducibility in digitized cephalometric radiography by comparing the measurement errors between the remeasured and retaken conventional and digitized lateral cephalometric radiography. The mean of the differences and error percentage of each cephalometric measurement were obtained using 96 lateral cephalometric radiography from 48 patients between the age of 11 and 13. The results were as follows; 1. The repeated measurement group of conventional radiography showed least amount of mean differences while those of the retaken measurement group of digitized image showed largest amount of mean differences in every measurement. 2. The measurements which showed statistically significant difference between the conventional radiography and digitized image were S-Go, Ar-Go, S-Ar-Go and S-sN-sNT in repeated measurement group. 3. The measurements which showed statistically significant difference between the repeated and retaken measurement groups were N-S-Ar, MP-L1 and S-sN-sPog in conventional radiography and S-N, Go-Me and N-A in digitized image. 4. Large amount of error percentage was shown at A-N-B and N-A in retaken measurement group of conventional radiography and N-S-Ba and A-N-B in retaken measurement group of digitized image. 5. The amount of error percentage at Ar-Go and N-S-Ar in retaken measurement group of conventional radiography and S-N, N-A, S-N-B and N-S-Ba in retaken measurement group of digitized image was more than double than those from remeasured groups.
Humans ; Radiography*

Background: Gamma irradiation has been often used for inactivating viable T lymphocytes in the blood product to prevent post-transfusion graft - vs - host disease (PT - GVHD) occurred in the recipients having immunodeficiency. But the irradiating method must be determined to minimize the reverse effects on other blood elements. Objectives: to evaluate the side effects of gamma irradiating with 25 Gy and in different ways on red cells in stored red cell concentrates. Subjects and methods: Each of 30 red cell concentrates was divided into 3 parts and treated in 3 different ways to create 3 groups of sample for studying. All the samples were stored 35 days at 4 - 6\xb0C and measured red cell osmotic fragility, hemoglobin (Hb) level in storage solution in days 1,7,14,21,28,35. Results: 1) Red cell osmotic fragility decreased and free Hb level increased with time in the samples of 3 groups. 2) Red cell osmotic fragility decreased strongly from the 28th day (p < 0.05) and free Hb level increased dramatically from the 14th day (p < 0.001) in the samples of group 2 compared to control group and group 3 with the same storage time, while there was no difference in these parameters in groups 1 and 3. Conclusion: 1) Gamma irradiation with 25 Gy affected the intact of red cells in red cell concentrates only when irradiated right after being produced and stored more than 14 days. 2) The quality of red cell would be unchanged if used immediately after irradiated. \r\n', u'\r\n', u'
Erythrocytes/ radiography

Background: Renal angiomyolipoma is devided into 2 types, one is solitary tumor and other is in patients with tuberous sclerosis (TB). The solitary type usually happens in middle aged women. The lesion usually appears in the right kidney. It occasionally has symptom and usually disovered incidentally. Complication is bleeding in large size tumors (> 4cm). Objective: To share experience in diagnosing and treating AML. Subject and Method: A report of a case of large angiomyyolipoma (AML) of the kidney, which ruptured into retroperitoneal space. The patient was a 53 years old women living in Hai Phong. She had clinical examinations and imaging diagnosis after hospitalization. Result and conclusion:The imaging procedures: ultrasound, Doppler, Computed Tomography (CT), Magnetic Resonance Imaging (MRl) and angiography (the goal is intervention) are applied. CT is the most important procedure for diagnosis in emergency cases. Treatment by intervening radiography, tumor rectomy or renal partial resectectomy.
Angiomyolipoma ; radiography

Background: Different target-filter combinations in computed radiography have different impacts on the dose and image quality in digital radiography. This study aims to evaluate the mean glandular dose (MGD) and modulation transfer function (MTF) of various target-filter combinations by investigating the signal intensities of X-ray beams. Methods: General Electric (GE) Senographe DMR Plus mammography unit was used for MGD and MTF evaluation. The measured MGD was compared with the dose reference level (DRL), whereas the MTF was evaluated using ImageJ 1.46o software. A modified Mammography Accreditation Phantom RMI 156 was exposed using different target-filter combinations of molybdenum-molybdenum (Mo-Mo), molybdenum-rhodium (Mo-Rh) and rhodium-rhodium (Rh-Rh) at two different tube voltages, 26 kV and 32 kV with 50 mAs. Results: In the MGD evaluations, all target-filters gave an MGD value of < 1.5 mGy. The one-way ANOVA test showed a highly significant interaction between the MGD and the kilovoltage and target-filter material used (26 kV: F (2,12) = 49,234, P = 0.001;32 kV: F (2,12) = 89,972, P = 0.001). A Tukey post-hoc test revealed that the MGD for 26 kV and 32 kV was highly affected by the target-filter combinations. The test of homogeneity of variances indicates that the MGD varies significantly for 26 kV and 32 kV images (0.045 and 0.030 (P < 0.05), respectively). However, the one-way ANOVA for the MTF shows that no significant difference exists between the target-filter combinations used with 26 kV and 32 kV images either in parallel or perpendicular to the chest wall side F (2,189) = 0.26, P > 0.05). Conclusions: Higher tube voltage and atomic number target-filter yield higher MGD values. However, the MTF is independent of the X-ray energy and the type of target-filter combinations used.
Mammography ; Radiography

No abstract available.
Hand* ; Radiography*

PURPOSE: To determine the head position that the superior border of the mandibular canal as well as mental foramen can be more clearly visualized in panoramic radiography MATERIALS AND METHODS: Ten dry mandibles were radiographed bilaterally using PM 2002 CC panoramic machine. A 20 mm thick aluminium filter was added to the slit collimator to obtain radiographs with acceptable density. The specimens were tilted by 2, 4, 6, 8, and 10 degrees downward with and without radiopaque markers. Radiopaque markers were inserted into the mandibular canals and the mental canals of each side of the specimens to serve as reference image when assessing the radiographs. The visibility of the mandibular canal and the mental foramen was estimated by 4 observers on all radiographs. The obtained results were analyzed statistically. RESULTS: Mandibular canals were significantly more clearly visible in the radiographs with 4 and 6 degree downward position on both sides (P<0.05). Mental foramens were significantly more clearly visible in the radiographs with 4, 6, and 8 degree downward on right side and 6 degree downward on left side (P<0.05). There was not significant difference between right and left sides. CONCLUSION: Panoramic radiographs with 4 to 6 degree downward tilting could be valuable in locating the mandibular canal as well as the mental foramen.
Head ; Mandible ; Radiography ; Radiography, Panoramic*

PURPOSE: To describe the characteristic HRCT appearance and to evaluate the usefulness of HRCT in patients with welders' pneumoconiosis. MATERIALS AND METHODS: Chest radiographs and high-resolution computed tomography(HRCT) of 45 shipyard welders(male : female=41 : 4 ; age : 36-58 years, mean 47.8) with an occupational history of 4-25(mean 15.8) years were evaluated. Small rounded opacities in chest radiographs were read accordingto the ILO standard films(1980). HRCT were evaluated with micronodules, ground-glass attenuation, and other findings. Serial HRCT scans of seven welders taken 27 months apart were also evalauted. Two of these were still working in that job ; five had not worked as welders for 1-6(mean 4.4) years. RESULTS: HRCT of welders' pneumoconiosis showed poorly marginated centrilobular branching or dot opacities of low attenuation(n=36, 80.0%)with variable profusion and extent and ground-glass attenuation(n=8, 17.8%). HRCT abnormalities were seen in 39 welders(86.7%). It was able to depict micronodules(n=13) and/or ground-glass attenuation(n=3) in 15(68.2%) of 22welders with normal chest radiograph. Serial HRCT revealed no changes in parenchymal abnormalities(n=6) andslightly decreased profusion of micronodules(n=1). There was no HRCT abnormality suggesting gross parenchymal fibrosis. CONCLUSION: HRCT is more sensitive than chest radiography in detecting parenchymal changes in welders' pneumoconiosis, with characteristic poorly-marginated centrilobular branching opacities or dots and ground-glass attenuation. These HRCT appearances may be helpful in differentiating welders' pneumoconiosis from other diffuse lung diseases.
Pneumoconiosis* ; Radiography ; Radiography, Thoracic ; Thorax

CT and MRI are utilized to differentiate between different types of masses and to determine the extent of lesions involving the lacrimal gland and the fossa. Although many diseases that affect the lacrimal gland and fossa are specifically diagnosed by imaging, it is frequently very difficult to differentiate each specific disease on the basis of image characteristics alone due to intrinsic similarities. In lacrimal gland epithelial tumors, benign pleomorphic adenomas are seen most commonly with a well defined benign appearance, and a malignant adenoid cystic carcinoma is seen with a typical invasive malignant appearance. However, a malignant myoepithelial carcinoma is seen with a benign looking appearance. Lymphomatous lesions of the lacrimal gland include a broad spectrum ranging from reactive hyperplasia to malignant lymphoma. These lesions can be very difficult to differentiate both radiologically and pathologically. Generally, lymphomas tend to occur in older patients. The developmental cystic lesions found in the lacrimal fossa such as dermoid and epidermoid cysts can be diagnosed when the cyst involves the superior temporal quadrant of the orbit and manifests as a non-enhancing cystic mass and, in case of a lipoma, it is diagnosed as a total fatty mass. However, masses of granulocytic sarcoma and xanthogranuloma, as well as vascular masses, such as a hemangiopericytoma, are difficult to diagnose correctly on the basis of preoperative imaging findings alone. A careful clinical evaluation and moreover, a pathologic verification, are needed. In this pictorial review, the various imaging spectrums of pathologic masses involving the lacrimal gland and fossa are presented, along with appropriate anatomy and pathology reviews.
Carcinoma, Squamous Cell/radiography ; Conjunctival Neoplasms/radiography ; Cysts/radiography ; Eye Neoplasms/*radiography ; Hemangiopericytoma/radiography ; Humans ; Lacrimal Apparatus/*pathology ; Lacrimal Apparatus Diseases/radiography ; Lipoma/radiography ; Lymphoma/radiography ; Neoplasms, Glandular and Epithelial/radiography ; Neurofibroma/radiography ; Sarcoma, Myeloid/radiography