• Journal of Veterinary Clinics
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• v.34 no.5
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• pp.330-334
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• 2017

The aim of this study was to establish an injection protocol of a test bolus and a main bolus of contrast material for computed tomographic pulmonary angiography (CTPA) for visualizing optimal pulmonary arteries in normal beagle dogs. CTPA using a test bolus method from either protocol A or B were performed in each of four normal beagle dogs. In protocol A, CTPA was conducted with a scan duration for around 8 s, setting the contrast enhancement peak of the pulmonary trunk in the middle of the scan duration. The arrival time to the contrast enhancement peak was predicted from a previous dynamic scan using a test bolus (150 mg iodine/kg) injected with the same injection duration using for a main bolus (450 mg iodine/kg). In protocol B, CTPA was started at the predicted appearance time of contrast material in the pulmonary trunk based on a previous dynamic scan using a test bolus injected with the same injection rate as a main bolus. CTPA using protocol A showed the optimal opacification of the pulmonary artery with pulmonary venous contamination. Proper CTPA images in the absence of venous contamination were obtained in protocol B. CTPA with a scan duration for 8 s should be started at the appearance time of contrast enhancement in the pulmonary trunk, which can be identified exactly when a test bolus is injected at the same injection rate used for the main bolus.

• Journal of Magnetics
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• v.22 no.2
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• pp.234-237
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• 2017

This study is aimed to optimize a location of region of interest (ROI) in test bolus carotid contrast enhanced magnetic resonance angiography (CE-MRA) at 3.0T. A total of consecutive 270 patients with no cardiovascular and vessel diseases were selected. Patients underwent elliptical centric 3D CE-MRA with the test bolus technique to identify the individual arterial arrival time. Quantitative measurements were performed by drawing ROIs of $25mm^2$ and signal intensities (SI) were measured in the center of common carotid artery (CCA), internal carotid artery (ICA) and aortic arch (AA). As a result, ROIs located within AA showed a significantly clarified arterial peak and over three times increased SI, while no significant arterial peak time differences were observed compared to ROIs located within CCA. In conclusion, it was demonstrated that the aortic arch is the optimal position to locate ROI in test bolus images of the carotid CE-MRA.

• Korean Journal of Radiology
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• v.1 no.2
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• pp.91-97
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• 2000

Objective: To determine whether the time-intensity curves acquired by test and main dose contrast injections for MR angiography are similar. Materials and Methods: In 11 patients, repeated contrast-enhanced 2D-turbo-FLASH scans with 1-sec interval were obtained. Both test and main dose timeintensity curves were acquired from the abdominal aorta, and the parameters of time-intensity curves for the test and main boluses were compared. The parameters used were arterial and venous enhancement times, arterial peak enhancement time, arteriovenous circulation time, enhancement duration and enhancement expansion ratio. Results: Between the main and test boluses, arterial and venous enhancement times and arteriovenous circulation time showed statistically significant correlation (p < 0.01), with correlation coefficients of 0.95, 0.92 and 0.98 respectively. Although the enhancement duration was definitely greater than infusion time, reasonable measurement of the end enhancement point in the main bolus was impossible. Conclusion: Only arterial and venous enhancement times and arteriovenous circulation time of the main bolus could be predicted from the test-bolus results. The use of these reliable parameters would lead to improvements in the scan timing method for MR angiography.

• Journal of the Korean Society of Radiology
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• v.14 no.6
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• pp.741-746
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• 2020

To investigate the radiation dose sensitivity in extremity radiatioin therapy depending on rice cultivar which have different size and shape of grains, plan results are compared that used rice bolus Korean and Thai rice. Phantoms that are each no bolus, Korean rice bolus, Thai rice bolus were used and prescribed 100 cGy to isocenter and checked the point dose of 12 points of interest of each phantoms. The meane dose are 103.57±1.98 cGy in Thai rice bolus using, 104.27±2.12 cGy in Korean rice bolus and 104.99±6.40 cGy in phantom without bolus. Dose distribution of Thai and Korean rice bolus differed significantly in Wilcoxon's Signed Rank test (p=.011). It has been confirmed that that the bolus using Thai rice, which has a small grain size, shows a more even dose distribution.

• Journal of Veterinary Clinics
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• v.35 no.3
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• pp.93-96
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• 2018

This study aimed to establish an injection protocol to determine the precise CT scan timing in canine abdominal multi-phase CT using the test bolus method. Three dynamic scans with different contrast injection parameters were performed using a crossover design in eight normal beagle dogs. A contrast material was administered at a fixed dose of 200 mg iodine/kg as a test bolus for dynamic scans 1 and 2, and 600 mg iodine/kg as a main bolus for dynamic scan 3. The contrast materials were administered with 1 ml/s in dynamic scan 1, and 3 ml/s in dynamic scan 2 and 3. The mean arrival time to the appearance of aortic enhancement in dynamic scan 3 was similar to that in dynamic scan 2, and different significantly to that in dynamic scan 1. The mean arrival time to the peak aortic and pancreatic parenchymal enhancement in dynamic scan 3 was similar to that in dynamic scan 1, and different significantly to that in dynamic scan 2. In multi-phase CT scan, a test bolus should be injected with the same injection duration of a main bolus, to obtain the precise arrival times to peak of arterial or pancreatic parenchymal enhancement.

• Proceedings of the KSMRM Conference
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• 1999.11a
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• pp.44-44
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• 1999

• Korean Journal of Digital Imaging in Medicine
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• v.13 no.3
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• pp.99-103
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• 2011

Radiation Therapy has been used in the treatment of breast cancer for over 80 years. Technically, it should include a part or all of such areas as chest wall or breast, axilla, internam mammary nodes and supraclavicular nodes. The purpose of this study is treated breast cancer patient to use 6 MV, 10 MV with bolus so that we observe changing of skin dose and evaluate those usefulness. Using woman's phantom, after CT simulate scanning, Through RTP system to make treatment plan, select three any place. And then, we measure that dose rate. After moving the phantom to linac, we put for TLD to three point same as RTP system which we put on the phantom. We exposed 6 MV, 10 MV with bolus and without so that it is measured dose by TLD device(4000 Harshaw). As a reult expose 6 MV,10 MV, it differences 10%, 15% according to bolus and withoout bolus where lateral point from RAO, LPO beam, other one is 20% where the furthest from both beams. To use bolus in the hospital is material to include closely part at skin among tissue of breast cancer. Acquired skin dose from RTP system is uncertainity. So it has to test another system likely TLD or other dosimetry system. Also exposed field of breast cancer is included inhomogeneity such as lung, bone and so on. Therefore it has to be accomplished a dose calculating of inhomogeneity part from treatment plan.

• The Journal of Korean Society for Radiation Therapy
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• v.18 no.2
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• pp.105-112
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• 2006

Purpose: To demonstrate that water bolus in the patient surface can decrease the dose inhomogeneity by patient surface large tissue defect when the surface is in an electron-beam field. And We tried to find a easy way to water control. Methods and Materials: To demonstrate the use of water bolus in the irregular surface clinically, the case of a patient with myxofibrosarcoma of the chest wall who was treated with electrons. We obtained dose distribution using missing tissue option of PINACLE 6.2b (ADAC, USA). We fabricate a Mev-green for water bolus in patient with defect of tissue. Then put the water bolus which is vinyl packed water into the designed Mev-green. We peformed CT scan with CT-simulator. Three-dimensional (3D) dose distributions with and without water bolus in the large irregular chest wall were calculated for a representative patient. Resulting dose distributions and dose-volume histograms of water bolus were compared with missing tissue option and non bolus plans. We fabricate a new water control device. Results: Controlled Water bolus markedly decrease the dose heterogeneity, and minimizes normal tissue exposure caused by the surface irregularities of the chest wall mass. In the test case, The non bolus plan has a maximum target dose of 132%. After applying water bolus, the maximum target dose has been reduced substantially to 110.4%. The maximum target dose was reduced by 21.6% using this technique. Conclusion: The results showed that controlled water bolus could significantly improve the dose homogeneity in the PTV for patients treated with electron therapy using water control device. This technique may reduce the incidence of normal organ complications that occur after electron-beam therapy in irregular surface. And our new device shows handiness of water control.

• Proceedings of the KSMRM Conference
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• 1999.11a
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• pp.107-107
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• 1999

• Korean Journal of Radiology
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• v.19 no.6
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• pp.1021-1030
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• 2018

Objective: We evaluated the effect of various patient characteristics and time-density curve (TDC)-factors on the test bolus-affected vessel enhancement on coronary computed tomography angiography (CCTA). We also assessed the value of generalized linear regression models (GLMs) for predicting enhancement on CCTA. Materials and Methods: We performed univariate and multivariate regression analysis to evaluate the effect of patient characteristics and to compare contrast enhancement per gram of iodine on test bolus (${\Delta}HUTEST$) and CCTA (${\Delta}HUCCTA$). We developed GLMs to predict ${\Delta}HUCCTA$. GLMs including independent variables were validated with 6-fold cross-validation using the correlation coefficient and Bland-Altman analysis. Results: In multivariate analysis, only total body weight (TBW) and ${\Delta}HUTEST$ maintained their independent predictive value (p < 0.001). In validation analysis, the highest correlation coefficient between ${\Delta}HUCCTA$ and the prediction values was seen in the GLM (r = 0.75), followed by TDC (r = 0.69) and TBW (r = 0.62). The lowest Bland-Altman limit of agreement was observed with GLM-3 (mean difference, $-0.0{\pm}5.1$ Hounsfield units/grams of iodine [HU/gI]; 95% confidence interval [CI], -10.1, 10.1), followed by ${\Delta}HUCCTA$ ($-0.0{\pm}5.9HU/gI$; 95% CI, -11.9, 11.9) and TBW ($1.1{\pm}6.2HU/gI$; 95% CI, -11.2, 13.4). Conclusion: We demonstrated that the patient's TBW and ${\Delta}HUTEST$ significantly affected contrast enhancement on CCTA images and that the combined use of clinical information and test bolus results is useful for predicting aortic enhancement.