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Radiation is useful but can be harmful to humans if used carelessly. Therefore, radiation protection equipment is necessary for workers. In this paper, we aim to study a cement composite with BaSO4/Bi2O3 for protection against X-rays and gamma rays. The shielding ability was measured using a diagnostic X-ray with energies of 60–120 keV and gamma rays of Cs-137, Ba-133, Co-57 and the morphology structure was determined including radiation protection properties. The results showed that Portland cement with a high concentration of BaSO4/Bi2O3 had the ability to absorb radiation from X-rays in the range of 95.54–99.87% and gamma energy in the range of 93.37–98.88%. Moreover, the composite of BaSO4/Bi2O3 induced a homogenous structure of Portland cement possibly affecting the strength of the material. In addition, Portland shielding can be designed for use in related applications in various energy ranges including ones that are environmentally friendly and suitable for the development of radiation protection in the future. [ABSTRACT FROM AUTHOR]

Metal artifacts often appear in the images of computed tomography (CT) imaging. In the case of lumbar spine CT images, artifacts disturb the images of critical organs. These artifacts can affect the diagnosis, treatment, and follow up care of the patient. One approach to metal artifact reduction is the sinogram completion method. A mixed-variable thresholding (MixVT) technique to identify the suitable metal sinogram is proposed. This technique consists of four steps: 1) identify the metal objects in the image by using k-mean clustering with the soft cluster assignment, 2) transform the image by separating it into two sinograms, one of which is the sinogram of the metal object, with the surrounding tissue shown in the second sinogram. The boundary of the metal sinogram is then found by the MixVT technique, 3) estimate the new value of the missing data in the metal sinogram by linear interpolation from the surrounding tissue sinogram, 4) reconstruct a modified sinogram by using filtered back-projection and complete the image by adding back the image of the metal object into the reconstructed image to form the complete image. The quantitative and clinical image quality evaluation of our proposed technique demonstrated a significant improvement in image clarity and detail, which enhances the effectiveness of diagnosis and treatment. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the five years average equivalent dose, the average collective equivalent dose and fatal cancer risk for the radiation workers in Radiology Department at Phramongkutklao Hospital., Material and Method: In the Radiology Department at Phramongkutklao Hospital, occupationally exposed workers are measured by the Division of Radiation Protection Services, Department of Medical Sciences which measures radiation exposures and evaluated doses from external exposures. Individual's doses of external exposure were monitored using film badges. The present study design describes a retrospective survey of occupational exposure in the Radiology Department at Phramongkutklao Hospital 2004-2008., Results: The distribution of radiation workers monitored according to the groups in the years 2004-2008, physicist, technologist and assistant of technologist were the most numerous occupational group (51.13%). Nurse, assistant of nurse and nurse aids constituted 22.73%. About 59.73% of radiation workers in the Radiology Department at Phramongkutklao Hospital received an annual average equivalent dose below 0.02 mSv which defined as recording level and no radiation workers received doses above the International Commission on Radiological Protection (ICRP) Publication 60 recommended dose limit (20 mSv per year). The five years average equivalent dose per radiation worker was 1.098 mSv. Of all occupational groups measurably exposed, the nuclear medicine group received the highest of the five years average equivalent dose, collective equivalent dose and fatal cancer risk. The five years average equivalent dose, collective equivalent dose and fatal cancer risk for the physicist, technologist and assistant of technologist were the highest., Conclusion: Total risk per the whole monitored radiation workers were 3.86 x lW due to receive the five years average collective equivalent dose 0.096 man Sv. These values were estimated from a very small of number of radiation workers.

Objective: To determine the lowest miliampere-second (mAs) of a cranial computed tomography (CT) scan that can maintain acceptable image quality on cranial CT scan which might help reducing the risk of cataract formation., Material and Method: The present study was performed on the 148 patients in routine daily practice sent for diagnosis of intracranial conditions by a cranial CT scan. During the cranial CT scanning, each lens's radiation dose on patient's eyes was measured by a thermoluminescent dosimeter Clinical image quality, particularly in analysis of gray and white matter differentiation, was evaluated independently using a 5 point scale by two radiologists., Results: During standard cranial CT scan protocol with 250 miliampere-second (mAs), the total dose of left and right lens's dose were about 50.93 miligray (mGy) and 51.66 mGy, respectively. When applying low dose cranial CT scan protocols by decreasing mAs to 200, 150 and 100 mAs, the total dose ofright and left lens were of 45.68 mGy and 46.04 mGy for 200 mAs, 34.65 mGy and 34.77 mGy for 150 mAs, 28.73 mGy and 29.25 mGy for 100 mAs respectively., Conclusion: A low dose cranial CT scan at 100 miliampere-second provides not only an acceptable clinical image quality, but also decreases the lens's radiation dose by 43%.

Objective: To evaluate the efficiency of quality control performance for a general x-ray machine between computed radiography (CR) and film method., Material and Method: CR performance as a quality control method for a general x-ray machine was compared to the film method. Two raters independently analyzed the result of quality control from both methods. Economic evaluation was performed by cost-minimization analysis. All data (result for quality control and cost) were collected from Phramongkutklao Hospital from August 2007 to January 2008., Result: Quality control performances of a general x-ray machine by using CR and film method were equivalent. Interobserver agreement for analysis of quality control measurements was almost perfect. Unit cost, test performance time, radiation dose for quality control by CR were less than the film method (p < 0.001)., Conclusion: The performances of quality control of a general x-ray machine done by the CR method are more efficient than the film method. Using the CR method for quality control performance of the general x-ray machines will save cost enormously.