• Progress in Medical Physics
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• v.17 no.4
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• pp.207-211
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• 2006

The advent of kV cone-beam computed tomography (CBCT) integrated with a linear accelerator allows for more accurate Image-guided radiotherapy (IGRT). IGRT is the technique that corrects target displacement based on internal body information. To do this, the CBCT Image set is acquired just before the beam is delivered and registered with the simulation CT Image set. In this study, we compare the registration results according to the CBCT's reconstruction quality (either high or medium). A total of 56 CBCT projection data from 6 patients were analyzed. The translation vector differences were within 1 mm in all but 3 cases. For rotation displacement difference, components of all three axes were considered and 3 out of 168 ($56{\times}3$ axes) cases showed more than lo of rotation differences.

• Restorative Dentistry and Endodontics
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• v.45 no.1
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• pp.1.1-1.9
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• 2020

Objectives: The purpose of this study was to determine the incidence of radix molaris (RM) (entomolaris and paramolaris) in the mandibular first permanent molars of a sample Saudi Arabian subpopulation using cone-beam computed tomography (CBCT). Materials and Methods: A total of 884 CBCT images of 427 male and 457 female Saudi citizens (age 16 to 70 years) were collected from the radiology department archives of 4 dental centers. A total of 450 CBCT images of 741 mature mandibular first molars that met the inclusion criteria were reviewed. The images were viewed at high resolution by 3 examiners and were analyzed with Planmeca Romexis software (version 5.2). Results: Thirty-three (4.5%) mandibular first permanent molars had RM, mostly on the distal side. The incidence of radix entomolaris (EM) was 4.3%, while that of radix paramolaris was 0.3%. The RM roots had one canal and occurred more unilaterally. No significant difference in root configuration was found between males and females (p > 0.05). Types I and III EM root canal configurations were most common, while type B was the only RP configuration observed. Conclusions: The incidence of RM in the mandibular first molars of this Saudi subpopulation was 4.5%. Identification of the supernumerary root can avoid missing the canal associated with the root during root canal treatment.

• Journal of radiological science and technology
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• v.33 no.4
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• pp.355-362
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• 2010

This study determines a range of CT parameter values in Brain CT which are minimizing patient absorption dose without compromising the image quality and optimal exposure condition. We measured dose and image noise using conventional CT parameters in Brain CT. In additon, we evaluated dose, SNR and PSNR of head phantom images while changing kVp and rotation time. In this study, effectiveness of dose that was achieved from dose reproducible experiments in conventional head CT condition is determined by changing kVp and rotation time. Dose and PSNR is related to low dose-high resolution condition. In conclusion, we suggest that using proposed conditions is effective for imaging to compare with conditions proposed by the manufacturer.

• Journal of the Korean Society of Radiology
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• v.82 no.4
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• pp.770-790
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• 2021

Idiopathic pulmonary fibrosis (IPF), based on the 2018 international clinical practice guidelines, can be diagnosed with a usual interstitial pneumonia (UIP) pattern on high-resolution computed tomography (HRCT) and compatible clinical findings. Given that imaging is pivotal for IPF evaluation and diagnosis, more emphasis should be placed on the integration of clinical, radiological, and pathologic findings for multidisciplinary diagnosis. Interstitial lung abnormality (ILA), on the other hand, has a purely radiological definition based on the incidental identification of CT abnormalities. Taken together, differentiation between ILA and clinically significant interstitial lung disease (ILD) must be based on proper clinical evaluation. With this review, the recent updates in IPF diagnosis and the radiologic considerations for ILA can be well understood, which can be helpful for the proper diagnosis and management of patients with diffuse interstitial pulmonary fibrosis.

• Clinical and Experimental Vaccine Research
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• v.13 no.1
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• pp.28-34
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• 2024

Purpose: Coronavirus disease 2019 (COVID-19) is a highly formidable disease. Globally, multiple vaccines have been developed to prevent and manage this disease. However, the periodic mutations of severe acute respiratory syndrome coronavirus 2 variants cast doubt on the effectiveness of commonly used vaccines in mitigating severe disease in the Indian population. This study aimed to assess the effectiveness of the BBV152 vaccine and ChAdOx1-S vaccine in preventing severe forms of the disease. Materials and Methods: This retrospective study, based on hospital records, was conducted on 204 vaccinated COVID-19 patients using a consecutive sampling approach. Data on their vaccination status, comorbidities, and high-resolution computed tomography lung reports' computed tomography severity scores were extracted from their medical records. Fisher's exact test and binomial logistic regression analysis were employed to assess the independent associations of various factors with the dependent variables. Results: Of the 204 records, 57.9% represented males, with a mean age of 61.5±9.8 years. Both vaccines demonstrated effective protection against severe illness (90.2%), with BBV152 offering slightly better protection compared to ChAdOx1-S. Male gender, partial vaccination, comorbid conditions, and the type of vaccine were identified as independent predictors of severe lung involvement. Conclusion: This study indicates that both vaccines were highly effective (90%) in preventing severe forms of the disease in fully vaccinated individuals. When comparing the two vaccines, BBV152 was slightly more effective than ChAdOx1-S in preventing severe COVID-19.

• Tuberculosis and Respiratory Diseases
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• v.60 no.3
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• pp.297-303
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• 2006

Background : Pulmonary tuberculosis is frequently accompanied with complications such as bronchiectasis, cavities, fibrosis and a deterioration of the lung function. However, there is little information available on the pathogenesis of these complications in pulmonary tuberculosis. Among the many factors involving in tissue remodeling, transforming growth factor-${\beta}1$ ($TGF-{\beta}1$) is a potent stimulus of the extracellular matrix fomation and a mediator of potential relevance for airway wall remodeling. Therefore, this study examined the relationship between the radiological changes and the $TGF-{\beta}1$ level in patients with pulmonary tuberculosis. Methods : Serum and bronchoalveolar lavage fluid (BALF) were collected from total of 35 patients before treating them for active pulmonary tuberculosis, and the $TGF-{\beta}1$ levels were measured using an enzyme-linked immunosorbent assay (ELISA). The BALF levels were recalculated as the epithelial lining fluid (ELF) levels using the albumin method. pulmonary function test (PFT) and high resolution computed tomography (HRCT) were performed before and after treatment. Results : There was a strong correlation between the serum $TGF-{\beta}1$ level and the presence of cavities (r=0.404, p=0.006), even though the BAL $TGF-{\beta}1$ level showed a weak correlation with complications. In addition, there was no correlation between the $TGF-{\beta}1$ levels before treatment and the changes in the PFT and HRCT during treatment. Conclusion : There is a correlation between the serum $TGF-{\beta}1$ level and cavity formation in pulmonary tuberculosis before treatment. However, further study will be needed to confirm this.

• Journal of Preventive Medicine and Public Health
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• v.29 no.4 s.55
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• pp.853-861
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• 1996

Pneumoconiosis is one of the major problem in the field of occupational health at Korea. Therefore, the efficient diagnosis of pneumoconiosis is a hot issue on the occupational health program. The author executed this study to estimate the diagnostic value of high resolution computed tomography(HRCT) compared with chest radiography for screening of welder's lung. HRCT was introduced very recently for the diagnosis of pneumoconiosis, however, the diagnostic value for screening of welder's lung - principally nonfibrogenic and reversible - has not been evaluated. The subjects were fifty cases of welder's lung or suspected cases who had been collected between 1989 and 1994 from one shipyard and continuously followed-up on the basis of in-plant periodic health check program. We applied both chest radiography and HRCT on the same subjects from May 1 to 30, 1996. The images were evaluated by two careered radiologists independently. The findings of chest radiography were classified into four category by ILO classification, and the findings of HRCT according to the criteria of Bergin et al. The concordance between two radiologists expressed with Kendall's tau-b was 0.72 by chest radiography and 0.44 by HRCT- that is, interobserver variation of HRCT was bigger than that of chest radiography. The concordance between the two different methods was highly variable as 0.44 by radiologist A and 0.06 by radiologist B - that is, interobserver variation was very big. However, HRCT looked more detectable for the minor parenchymal change. These findings suggested that it is not appropriate to use HRCT routinely for screening of welder's lung due to lack of diagnostic criteria, and feasibility, acceptability and economic aspects. Nevertheless, HRCT might be recommendable in the case of equivocal parenchymal features on the chest radiography, unexplained respiratory symptoms, and/or lung function abnormalities suggestive of interstitial fibrosis.

• Journal of Radiation Industry
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• v.11 no.3
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• pp.131-137
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• 2017

To compare the radiation dose and image noise of low dose computed tomography (CT) and high resolution CT using the fixed tube current technique and automatic tube current modulation (CARE Dose 4D). Chest CT and human anthropomorphic phantom were used the RPL (radiophotoluminescence) dosimeters. For image evaluation, standard deviation of mean CT attenuation coefficient and CT attenuation coefficient was measured using ROI analysis function. The effective dose was calculated using CTDIvol and DLP. CARE Dose 4D was reduced by 74.7% and HRCT by 64.4% compared to the fixed tube current technique in low dose CT of chest phantom. In CTDIvol and DLP, the dose of CARE Dose 4D was reduced by fixed tube current technique. For effective dose, CARE Dose 4D was reduced by 47% and HRCT by 46.9% compared to the fixed tube current method, and the dose of CARE Dose 4D was significantly different (p<.05). Noise in the image was higher than that in the fixed tube current technique. Noise difference in the image of CARE Dose 4D in low dose CT was significant (p<.05). The low radiation dose and the noise difference of the CARE Dose 4D were compared with the fixed tube current technique in low dose CT and HRCT using chest phantom. The radiation doses using CARE Dose 4D were in accordance with the national and international dose standards. CARE Dose 4D should be applied to low dose CT and HRCT for clinical examination.

• Tuberculosis and Respiratory Diseases
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• v.63 no.3
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• pp.294-298
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• 2007

Pulmonary alveolar proteinosis is a rare disorder that is characterized by the abundant accumulation of surfactant-derived material within the alveolar spaces and distal bronchioles. Although the findings of homogenous ground-glass opacities overlaid by thickened septa, which form a "crazy paving" pattern on high-resolution computed tomography, can assist in making a diagnosis, a lung biopsy is usually required. This disorder has a variable clinical course, from spontaneous resolution to respiratory failure and death. While a whole lung lavage has been the standard treatment since the early 1960s, GM-CSF therapy has been attempted based on the recently suggested pathogenetic mechanism. We report a case of pulmonary alveolar proteinosis that resolved spontaneously after an open lung biopsy.

• Imaging Science in Dentistry
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• v.47 no.3
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• pp.165-174
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• 2017

Purpose: This study was performed to investigate the influence of object shape and distance from the center of the image on the volumetric accuracy of cone-beam computed tomography (CBCT) scans, according to different parameters of tube voltage and current. Materials and Methods: Four geometric objects(cylinder, cube, pyramid, and hexagon) with predefined dimensions were fabricated. The objects consisted of Teflon-perfluoroalkoxy embedded in a hydrocolloid matrix (Dupli-Coe-Loid TM; GC America Inc., Alsip, IL, USA), encased in an acrylic resin cylinder assembly. An Alphard Vega Dental CT system (Asahi Roentgen Ind. Co., Ltd, Kyoto, Japan) was used to acquire CBCT images. OnDemand 3D (CyberMed Inc., Seoul, Korea) software was used for object segmentation and image analysis. The accuracy was expressed by the volume error (VE). The VE was calculated under 3 different exposure settings. The measured volumes of the objects were compared to the true volumes for statistical analysis. Results: The mean VE ranged from -4.47% to 2.35%. There was no significant relationship between an object's shape and the VE. A significant correlation was found between the distance of the object to the center of the image and the VE. Tube voltage affected the volume measurements and the VE, but tube current did not. Conclusion: The evaluated CBCT device provided satisfactory volume measurements. To assess volume measurements, it might be sufficient to use serial scans with a high resolution, but a low dose. This information may provide useful guidance for assessing volume measurements.