• Radiation Oncology Journal
• /
• v.28 no.4
• /
• pp.238-248
• /
• 2010

Purpose: To compare the dose distributions between three-dimensional (3D) and four-dimensional (4D) radiation treatment plans calculated by Ray-tracing or the Monte Carlo algorithm, and to highlight the difference of dose calculation between two algorithms for lung heterogeneity correction in lung cancers. Materials and Methods: Prospectively gated 4D CTs in seven patients were obtained with a Brilliance CT64-Channel scanner along with a respiratory bellows gating device. After 4D treatment planning with the Ray Tracing algorithm in Multiplan 3.5.1, a CyberKnife stereotactic radiotherapy planning system, 3D Ray Tracing, 3D and 4D Monte Carlo dose calculations were performed under the same beam conditions (same number, directions, monitor units of beams). The 3D plan was performed in a primary CT image setting corresponding to middle phase expiration (50%). Relative dose coverage, D95 of gross tumor volume and planning target volume, maximum doses of tumor, and the spinal cord were compared for each plan, taking into consideration the tumor location. Results: According to the Monte Carlo calculations, mean tumor volume coverage of the 4D plans was 4.4% higher than the 3D plans when tumors were located in the lower lobes of the lung, but were 4.6% lower when tumors were located in the upper lobes of the lung. Similarly, the D95 of 4D plans was 4.8% higher than 3D plans when tumors were located in the lower lobes of lung, but was 1.7% lower when tumors were located in the upper lobes of lung. This tendency was also observed at the maximum dose of the spinal cord. Lastly, a 30% reduction in the PTV volume coverage was observed for the Monte Carlo calculation compared with the Ray-tracing calculation. Conclusion: 3D and 4D robotic radiotherapy treatment plans for lung cancers were compared according to a dosimetric viewpoint for a tumor and the spinal cord. The difference of tumor dose distributions between 3D and 4D treatment plans was only significant when large tumor movement and deformation was suspected. Therefore, 4D treatment planning is only necessary for large tumor motion and deformation. However, a Monte Carlo calculation is always necessary, independent of tumor motion in the lung.

• Journal of Korea Multimedia Society
• /
• v.23 no.6
• /
• pp.729-737
• /
• 2020

Screening with low-dose spiral computed tomography (LDCT) has been shown to reduce lung cancer mortality by about 20% when compared to standard chest radiography. One of the problems arising from screening programs is that large amounts of CT image data must be interpreted by radiologists. To solve this problem, automated detection of pulmonary nodules is necessary; however, this is a challenging task because of the high number of false positive results. Here we demonstrate detection of pulmonary nodules using six off-the-shelf convolutional neural network (CNN) models after modification of the input/output layers and end-to-end training based on publicly databases for comparative evaluation. We used the well-known CNN models, LeNet-5, VGG-16, GoogLeNet Inception V3, ResNet-152, DensNet-201, and NASNet. Most of the CNN models provided superior results to those of obtained using customized CNN models. It is more desirable to modify the proven off-the-shelf network model than to customize the network model to detect the pulmonary nodules.

• Proceedings of the KOSOMBE Conference
• /
• v.1990 no.05
• /
• pp.33-37
• /
• 1990

In this paper, a new method for lung area segmentation in chest radiographs has been presented. The movivation of this study is to include fuzzy informations about the relation between the image date structure and the area to be segmented in the segmentation process efficiently. The proposed method approached the segmentation problem in the perspective of pattern classification, using trainable pattern classifier, multi-layer perceptron. Having been trained with 10 samples, this method gives acceptable segmentation results, and also demonstrated the desirable property of giving better results as the training continues with more training samples.

• Journal of radiological science and technology
• /
• v.41 no.2
• /
• pp.97-102
• /
• 2018

The purpose of this study is to provide the basic data for reducing unnecessary radiation dose to the abdomen and fetus of pregnant women by presenting proper height of shielding protector for efficient abdominal shielding in chest PA examination of Korean pregnant women. The subjects of this study were 288 persons who were eligible for this study among 798 pregnant women who had chest PA examination from January 1, 2015 to December 31, 2016 Retrospective study was performed. Measurements was performed from the apex of the right and left lungs to costophrenic angle of the right and left lungs and to the lowest costophrenic angle among the right and left lungs at the top of the image(this line called Joo's line in this study). The mean of the right and left lung height of pregnant women were 259.09 mm and 263.57 mm, respectively. Also, the average height of the Joo's line designed by the researcher for proper abdominal radiation protection was 322.15 mm. For proper and efficient abdominal radiation protection for pregnant women, it is necessary to adjust the shielding according to the height of the pregnant woman. It is appropriate that the height of the shielding protector should be adjusted so that the upper part of the shield is located at 342.30 mm below from upper part of the detector.

• Journal of Veterinary Clinics
• /
• v.22 no.4
• /
• pp.431-434
• /
• 2005

A 2-year-old castrated male, Cocker spaniel dog with a history of chronic productive cough for 2 to 3 months and with unsuccessful treatment was referred to Veterinary Medical Teaching Hospital, Seoul National University. On thoracic radiographs, there were alveolar infiltrations at left cranial and right caudal lung fields, and soft-tissue opacity round to oval images at overall lung field. The bronchi were dilated, tortuous and not tapered. Abnormal air was accumulated focally in the caudodorsal lung fields. To scrutinize the soft-tissue opacity image and accumulated air, computed tomography (CT) was done. On CT images, severe cylindrical or tubular bronchiectasis was confirmed. And the soft-tissue opacity images were found in the dilated bilated and thought to complexes of mucous plugs, inflammatory cells, necrotic and fibrotic tissue. The dog was dead next day to the CT scan, so necropsy and histopathologic examination were perfermed. On the histopathology, there were cylindrical bronhiectasis and severe diffuse chronic fibrinous necropurulent bronchitis and bronchopneumonia. In this case, it was difficult to diagnose the bronchiectasis only with radiography due to the concurrent lesions, such as pulmonary infiltrations and mucous plugs, which was identified by computed tomography. Thus, computed tomography is considered as a useful modality to confirm tile bronchiectasis camouflaged by the concurrent lesion.

• Korean Journal of Radiology
• /
• v.22 no.7
• /
• pp.1203-1212
• /
• 2021

Objective: To investigate the diagnostic accuracy and complications of cone-beam CT-guided percutaneous transthoracic needle biopsy (PTNB) of juxtaphrenic lesions and identify the risk factors for diagnostic failure and complications. Materials and Methods: In total, 336 PTNB procedures for lung lesions (mean size ± standard deviation [SD], 4.3 ± 2.3 cm) abutting the diaphragm in 326 patients (189 male and 137 female; mean age ± SD, 65.2 ± 11.4 years) performed between January 2010 and December 2014 were included. The accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the PTNB procedures for the diagnosis of malignancy were measured based on the intention-to-diagnose principle. The risk factors for diagnostic failures and complications were evaluated using logistic regression analysis. Results: The accuracy, sensitivity, specificity, PPV, and NPV were 92.7% (293/316), 91.3% (219/240), 91.4% (74/81), 96.9% (219/226), and 77.9% (74/95), respectively. There were 23 diagnostic failures (7.3%), and lesion sizes ≤ 2 cm (p = 0.045) were the only significant risk factors for diagnostic failure. Complications occurred in 98 cases (29.2%), including 89 cases of pneumothorax (26.5%) and 7 cases of hemoptysis (2.1%). The multivariable analysis showed that old age (> 65 years) (p = 0.002), lesion size of ≤ 2 cm (p = 0.003), emphysema (p = 0.006), and distance from the pleura to the target lesion (> 2 cm) (p = 0.010) were significant risk factors for complications. Conclusion: The diagnostic accuracy of cone-beam CT-guided PTNB of juxtaphrenic lesions for malignancy was fairly high, and the target lesion size was the only significant predictor of diagnostic failure. Complications of cone-beam CT-guided PTNB of juxtaphrenic lesions occurred at a reasonable rate.

• Korean Journal of Radiology
• /
• v.21 no.5
• /
• pp.526-536
• /
• 2020

Objective: This study aimed to evaluate the clinical benefits and risks of CT-guided percutaneous transthoracic needle lung biopsies (PTNBs) in patients with a suspected pulmonary infection. Materials and Methods: This study included 351 CT-guided PTNBs performed in 342 patients (mean age, 58.9 years [range, 17-91 years]) with suspected pulmonary infection from January 2010 to December 2016. The proportion of biopsies that revealed the causative organism for pulmonary infection and that influenced patient's treatment were measured. Multivariate analyses were performed to identify factors associated with PTNB that revealed the causative organism or affected the treatment. Finally, the complication rate was measured. Results: CT-guided PTNB revealed the causative organism in 32.5% of biopsies (114/351). The presence of necrotic components in the lesion (odds ratio [OR], 1.7; 95% confidence interval [CI], 1.1-2.7; p = 0.028), suspected pulmonary tuberculosis (OR, 2.0; 95% CI, 1.2-3.5; p = 0.010), and fine needle aspiration (OR, 2.5; 95% CI, 1.1-5.8; p = 0.037) were factors associated with biopsies that revealed the causative organism. PTNB influenced patient's treatment in 40.7% (143/351) of biopsies. The absence of leukocytosis (OR, 1.9; 95% CI, 1.0-3.7; p = 0.049), presence of a necrotic component in the lesion (OR, 2.4; 95% CI, 1.5-3.8; p < 0.001), and suspected tuberculosis (OR, 1.7; 95% CI, 1.0-2.8; p = 0.040) were factors associated with biopsies that influenced the treatment. The overall complication rate of PTNB was 19% (65/351). Conclusion: In patients with suspected pulmonary infection, approximately 30-40% of CT-guided PTNBs revealed the causative organism or affected the treatment. The complication rate of PTNB for suspected pulmonary infection was relatively low.

• Journal of the Korean Society of Radiology
• /
• v.85 no.3
• /
• pp.631-636
• /
• 2024

Pleural metastasis is the most common cause of malignant diseases involving the pleura, and characterized by pleural effusion, nodules, and thickening. Pleuroparenchymal fibroelastosis (PPFE) is a disease characterized by apical pleural thickening and subjacent parenchymal fibrosis. We report a case of a 60-year-old male with lung cancer in the left lower lobe and underlying PPFE combined with left apical pleural metastasis. Initially, asymmetric left apical pleural thickening due to pleural metastasis was mistaken for PPFE. Additionally, we describe the imaging and histopathological findings of PPFE, including MRI findings.

• Journal of radiological science and technology
• /
• v.39 no.3
• /
• pp.391-397
• /
• 2016

Stereotactic body radiotherapy is effective technic in radiotherapy for low stage lung cancer. But lung cancer is affected by respiratory so accurately concentrate high dose to the target is very difficult. In this study, evaluated the target volume according to how to take the image. And evaluated the dose by photoluminescence glass dosimeter according to how to contour the volume and respiratory range. As a result, evaluated the 4D CT volume was 10.4 cm3 which was closest value of real size target. And in dose case is internal target volume dose was 10.82, 16.88, 21.90 Gy when prescribed dose was 10, 15, 20 Gy and it was the highest dose. Respiratory gated radiotherapy dose was more higher than internal target volume. But it made little difference by respiratory range. Therefore, when moving cancer treatment, acquiring image by 4D CT, contouring internal target volume and respiratory gated radiotherapy technic would be the best way.

• Progress in Medical Physics
• /
• v.19 no.4
• /
• pp.201-208
• /
• 2008

Physical evaluations provide the basis for an objective and quantitative analysis of the image quality. Nonetheless, there are limitations in using physical evaluations to judge the utility of the image quality if the observer's subjectivity plays a key role despite its imprecise and variable nature. This study proposes a new method for objective and quantitative evaluation of image quality to compensate for the demerits of both physical and subjective image quality and combine the merits of them. The images of chest phantom were acquired from four digital radiography systems on clinic sites. The physical image quality was derived from an image analysis algorithm in terms of the contrast-to-noise ratio (CNR) of the low-contrast objects in three regions (lung, heart, and diaphragm) of a digital chest phantom radiograph. For image analysis, various image processing techniques were used such as segmentation, and registration, etc. The subjective image quality was assessed by the ability of the human observer to detect low-contrast objects. Fuzzy integral was used to integrate them. The findings of this study showed that the physical evaluation did not agree with the subjective evaluation. The system with the better performance in physical measurement showed the worse result in subjective evaluation compared to the other system. The proposed protocol is an integral evaluation method of image quality, which includes the properties of both physical and subjective measurement. It may be used as a useful tool in image evaluation of various modalities.