• Journal of radiological science and technology
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• v.46 no.2
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• pp.99-106
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• 2023

The height of the table should be considered important during computed tomography (CT) examination, but according to previous studies, not all radiology technologists set the table at the patient's center at the examination, which affects the exposure dose and image quality received by the patient. Therefore, this study intends to study the image quality exposure dose according to the height of the table to realize the optimal image quality and dose during the brain CT scan. The head phantom images were acquired using Philips Brilliance iCT 256. When the image was acquired, the table height was adjusted to 815, 865, 915, 965, 1015, and 1030 mm, respectively, and each scan was performed 3 times for each height. For the exposure dose measurement, optically stimulated luminescence dosimeter (OSLD) was attached to the front, side, eye, and thyroid gland of the head phantom. In the signal to noise ratio (SNR) measurement result, The SNR values for each table height were all lower than 915 mm. As a result of exposure dose, the exposure dose on each area increased as the table height decreased. The height of the table has a close relationship with the patient's radiation exposure dose in the CT scan.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.3
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• pp.86-91
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• 2009

Purpose: The whole body scan in Nuclear Medicine is a widely accepted examination and procedure. Especially, it is mainly used in bone, I-131, MIBI, and HMPAO WBC scans. The diverse uses of the whole body scan range from the HMPAO WBC scan with a speed of 13cm/min, to a whole body bone scan using the Onco. Flash technique with a speed of 30cm/min. The accuracy of table movement has a strong correlation with the image quality, and inaccuracy of speed could negatively affect the image quality. The purpose of this study is to evaluate the accuracy of the table movement while considering the influence of the age of the equipment and the variability in the weight of the patients. Material and Methods: The study was conducted using two of Seoul Asan Medical Center's SIEMENS gamma cameras which are commonly used in our whole body study. The first one is the oldest gamma camera, an ECAM plus (installed in 2000), and the last is brand new one, a SYMBIA T2 (installed in 2008). Three trials were conducted with the tables moving at a different speed each time; 10, 15 and 30 cm/min. The tables' speeds were measured by checking how long it took for the table to move 10cm, and this was repeated every 10cm until the table reached 100 cm. With an average body weight of the patients of about 60~70 kg, the table speed was measured with weights of 0 kg, 66 kg and 110 kg placed on the table, then compared among conditions. Results: The coefficient of variance (CV) of the ECAM plus showed 1.23, 1.42, 2.02 respectively when the table movement speeds were set at 10, 15, and 30 centimeters per minute. Under the same conditions, the SYMBIA T2 showed 1.23, 1.83 and 2.28 respectively. As table movement speed more, the variance of CV as the speed increases. When the patient body weight was set to 0, 66 and 110kg, the CV values of both cameras showed 0.96, 1.45, 2.08 (0 Kg), 1.32, 1.72, 2.27 (66 Kg) and 1.37, 1.73, 2.14 (110 Kg). There was no significant difference (p>0.05) in 95 percent of confidence intervals and measured CV values were acceptable. However, the CV value of the SYMBIA T2 was relatively larger than the ECAM plus. Conclusion: The scan speed of the whole body scan is predetermined based on which examination is being performed. It is possible for the accuracy of the speed to be affected, such as the age of the equipment, the state of the bearings or the weight of a patient. These factors can have a negative impact on the diagnostic consistency and the image quality. Therefore, periodic quality control should be needed on the gamma cameras currently being used, focusing on the table movement speed in order to maintain accuracy and reproducibility.

• The Transactions of the Korea Information Processing Society
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• v.5 no.11
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• pp.2835-2844
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• 1998

Most data parallel languages provide the block-cyclic distribution (cyclic(k)) that is one of the most general regular distributions. In order to generate local addresses for an array section A(l:h:s) with block-cyclic distribution, efficient compiling methods or run-time methods are required. In this paper, two local address generation methods for the block-cyclic distribution are presented. One is a simple scan method that is modified from the virtual-block scheme. The other is a linear-time ${\Delta}M$ table that contains the local memory access information construction method. This method is simpler than other algorithms for generating a ${\Delta}M$ table. Experimental results show that a simple that a simple scan method has poor performance but a linear-time ${\Delta}M$ table generation method is faster than other algorithms in ${\Delta}M$ table generation time and access time for 10,000 array elements.

• Journal of the Korean Data and Information Science Society
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• v.15 no.1
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• pp.83-94
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• 2004

In this study we analyze categorical data by means of spatial statistics and echelon analysis. To do this, we first determine the hierarchical structure of a given contingency table by using echelon dendrogram then, we detect candidates of hotspots given as the top echelon in the dendrogram. Next, we evaluate spatial scan statistics for the zones of significantly high or low rates based on the likelihood ratio. Finally, we detect hotspots of any size and shape based on spatial scan statistics.

• Korean Journal of Digital Imaging in Medicine
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• v.13 no.1
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• pp.39-48
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• 2011

Uses a Tomographic scan image and Table Object Distance(TOD) price after measuring, uses accuracy and usability of blood vessel diameter(Vessel Diameter) measurement under comparison evaluating boil TOD Calibration. The patient who enforces Prosecuting Attorney abdomen Tomographic scan in the object the superior mesentery artery uses PACS View from abdomen fault image and from blood vessel diameter and the table measures the height until of the blood vessel. Uses Angio Catheter from Angiography(5 Fr.) and enforces is measured from PACS View the height until of the table which and the blood vessel at TOD Calibration price and the size of the superior mesentery artery inputs measures an superior mesentery artery building skill. Catheter Calibration input Agnio Catheter where uses in Angiography the size of the superior mesentery artery at Catheter Calibration price and they measure. Produced an accuracy from monitoring data and comparison evaluated. The statistical program used SPSS. TOD Calibration accuracy was 96.53%, standard deviation is 0.03829. Catheter Calibration accuracy of 92.91%, standard deviation is 0.05085. Represents a statistically significant difference(p = 0). According to age and gender was not statistically significant(p > 0.05). TOD Calibration correlation coefficient R-squared of 88.8%, Catheter Calibration of the R-squared is 75.5%. High accuracy of both methods. Through this study, CT images using the measured distance between the table and the Object, TOD Calibration accuracy higher than two Catheter Calibration was measured. TOD and Catheter Calibration represents a statistically significant difference(p = 0).

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.6
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• pp.22-34
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• 2010

Existing image scalers generally adopt simple interpolation methods such as bilinear method to take cost-benefit, or highly complex architectures to achieve high quality resulting images. However, demands for a low power, low cost, and high performance image scaler become more important because of emerging high quality mobile contents. In this paper we propose the novel low power hardware architecture for a high quality raster scan image scaler. The proposed scaler architecture enhances the existing cubic interpolation look-up table architecture by reducing and optimizing memory access and hardware components. The input data buffer of existing image scaler is replaced with line memories to reduce the number of memory access that is critical to power consumption. The cubic interpolation formula used in existing look-up table architecture is also rearranged to reduce the number of the multipliers and look-up table size. Finally we analyze the optimized parameter sets of look-up table, which is a trade-off between quality of result image and hardware size.

• Progress in Medical Physics
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• v.11 no.1
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• pp.59-71
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• 2000

It is possible to obtain a fast CT scan during breath holding with spiral technique. But the risk of radiation is increased due to detailed and repeated scans. However, the limitation of X-ray doses is not fully specified on CT, yet. Therefore, the purpose of the present study is to define the limitation of X-ray doses on CT The CT unit was somatom plus 4. Alderson Rando phantom, Solenoid water phantom, TLD, and reader were used. For determining adequate position and size of organs, the measurement of distance(${\pm}$2mm) from the midline of vertebral body was performed in 40 women(20~40 years). On the brain scan for 8:8(8mm slice thickness, 8mm/sec movement velocity of the table) and 10:10(10mm slice thickness, 10mm/sec movement velocity of the table) methods, the absorption doses of exposed area of the 10:10 were slightly higher than those of 8:8. The doses of unexposed uterus were negligible on the brain scan for both 8:8 and 10:10. On the chest scan for 8:8, 8:10(8mm slice thickness, 10mm/sec movement velocity of the table), 10:10, 10:12(10mm slice thickness, 12mm/sec movement velocity of the table) and 10:15(10mm slice thickness, 15mm/sec movement velocity of the table) methods, 8:8 method of the absorption doses of exposure area was the most highest and 10:15 method was the most lowest. The absorption doses of 8:10 method was relatively lower than those of the other methods. In conclusion, the 8:10 method is the most suitable to give a low radiation burden to patient without distorting image quality.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.1
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• pp.40-46
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• 2009

Purpose: A whole body scan using a radioactive iodine (I-131) for the patients with differentiated thyroid cancer is generally an useful method to detect the remnant thyroid tissue, recurred lesion or metastasis lesion after a surgery. The high dose treatment using the radioactive iodine recently tends to increase, and a hospitalization wait for the treatment has been delayed for several months. In this hospital, the treatable patients per week were increased in number through expanding a water-purifier tank and the examination time also increased as the I-131 whole body scan patients increased. Improvement for this problem, this research reduce the existing examination time and classifying the lesion's exact position intended to by fabricating and utilizing the transmission scan tool and an excellent resolution for whole body imaging. Materials and Methods: After conducting the whole body scan for patients who visited the department from February to July 2008 and received the I-131 whole body scan using the ORBITER Gamma Camera. A rail was installed in the examination table for the transmission scan for show a contour of surface area and then the transmission image was obtained and fused to the whole body scan through fabricating the tool to put a flood phantom of diluted 2 mCi $^{99m}Tc$-pertechnetate. Results: Fused image of I-131 whole body scan and the transmission scan had the excellent resolution to discriminate an oral cavity or salivary gland region, neck region's lesion, and metastasis region's position through a simple marking, and could reduce the examination time of 8~28 minutes because without the additional local image. Conclusions: In I-131 whole body scan, the transmission scan can accurately show a contour of surface area through the attenuation of radioactivity, and is useful to indicate the remnant thyroid tissue or metastasis lesion's position by improving the resolution through the fusion image with alreadyexecuted I-131 whole body scan. Also, because the additional local image is not necessary, it can reduce the time required for the examination. It will extensively apply to other clinical examinations to be helpful for identifying an anatomical position because it shows the contour of surface area.

• The Korean Journal of Nuclear Medicine
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• v.3 no.1
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• pp.59-67
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• 1969

Correlation between the blood clearance half time and findings of liver scan using the colloidal radiogold in patients of liver cirrhosis is observed through the scoring system, in which the more changes in size, shape and density in the liver scan, the more points are given (table 1). Results: 1) Within the increase in severity of hepatocellular dysfunction in liver cirrhosis, the degree and frequency of following changes in liver scan (done with colloidal radiogold) were increased in order. a) generalized hepatomegaly b) enlargement of the left lobe & reduction of the right lobe c) relatively increased radiodensity in the left lobe and 4) visualization of spleen. 2) Frequency of the normal scan in liver cirrhosis was $12{\pm}3.56%$, frequency of normal value in blood clearance half time of the radiogold was $5.0{\pm}2.34%$ and frequency of normal scan & normal blood clearance rate in liver cirrhosis was $3.6{\pm}2.06%$.

• ETRI Journal
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• v.33 no.3
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• pp.374-381
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• 2011

A simple and effective compression method is proposed for multiple-scan testing. For a given test set, each test pattern is compressed from the view of slices. An encoding table exploiting seven types of frequently-occurring pattern is used. Compression is then achieved by mapping slice data into codewords. The decompression logic is small and easy to implement. It is also applicable to schemes adopting a single-scan chain. Experimental results show this method can achieve good compression effect.