• Journal of radiological science and technology
• /
• v.20 no.2
• /
• pp.56-62
• /
• 1997

To evaluated the image quality and the patient exposure for the chest radiography, its fundamental imaging properties were investigated. The basic imaging properties were evaluated by measuring characteristic curves, relative speeds, average gradient, and patient exposure dose. The image qualities were evaluated by using a rotating meter. It was found that the film gradient of SRO750/SRH system was 3.13 and that of SRO750/HR-C30 was 1.77. The ratio of SRO1000/TMH to FS/RP-1 was 1 to 18.2. It was possible to visualize the static image when the exposure time was less than 2.5 msec in patient that had respiratory excessive motion, heart beat and natural physical motion, and less than 8.5 msec in normal. The ratio of medical exposure dose compared with our method was 1 to 25 in the routine chest radiography and maximum was 1 to 70. In estimation of the image quality in same cases, we found that the image of SRO1000/SRH and TMH of super sensitive systems was the same results. We found that these super sensitive screen-film systems were available for the chest radiography considering the relationship between the image quality and patient exposure.

• Journal of the Korean Society of Radiology
• /
• v.8 no.4
• /
• pp.203-210
• /
• 2014

Chest radiography has been typically performed at SID of 180 cm. Image quality and patient dose were investigated between 180 cm and 340 cm by 20 cm intervals at 120 kVp and 320 mAs with the AEC. VGA was performed for qualitative assessment and SNR was analysed for quantitative assessment on the image of the chest phantom. Patients dose was measured by ESAK and PCXMC was used for effective dose. As a result, when using the standard of SID of 180 cm which is typically used in the clinical practice, in the case of ESAK, 240 cm, 280 cm, and 320 cm were 8.7%, 11.47%, and 13.56% respectively therefore significant reduction was confirmed. In the case of effective dose, 2.89%, 4.67%, and 6.41% in the body and 5.08%, 6.09%, and 9.6% in lung were reduced. In the case of SNR, 9.04%, 8.24%, and 11.46% were respectively decreased especially, by 8.03% between SID of 260 cm and 300 cm, but SNR was 5.24 up to 340 cm. There were no significant differences in VGA thus the image is valuable in diagnosis. It is predicted that increasing SID up to 300 cm in digital chest radiography can reduce patient dose without decreasing image quality.

• 전자공학회논문지 IE
• /
• v.48 no.1
• /
• pp.51-56
• /
• 2011

In this paper, a variety of digital image processing technique was applied to improve the quality of medical images which is a chest CR image. And the image quality was performed. On the other hand, the high-frequency emphasis filtering and the histogram equalization were realized by MATLAB programs to better the contrast of the chest CR image. As a result of simulation, the sharpness of the original image was elevated by the high-frequency emphasis filtering and the histogram equalization. To evaluate the degree which is improved the image quality by the digital image processing, the subjective evaluation is used by the observation of the image. The sensitivity which is the probability to find a signal or a lesion is calculated. The sensitivity of the image performed the high-frequency emphasis filtering and the histogram equalization became more improved than that of the original and the digital image processing performed in the medical image improved the quality of the image.

• Journal of Biomedical Engineering Research
• /
• v.13 no.1
• /
• pp.25-32
• /
• 1992

A new restoration method of chest X -ray image (dual project filter) was proposed to improve SNR(signal to noise ratio) characteristics. In this method, a priori Information of system and anatomical structure and statistics of projected object are used in the design of filter. Dual projection filter varies its parameters, adapting to the local regions of chest(lung region, mediasternum, subdiaphragm) and the structure of chest (bone, tissue, blood vessel, bronchia). The performance of Dual Projection Filter was 0.1-0.2dB better than Dual Sensor Wiener Filter, which was used for initial estimate of Dual Porjection Filter.

• 제어로봇시스템학회:학술대회논문집
• /
• 1991.10a
• /
• pp.741-745
• /
• 1991

This paper describes a feature extraction in digitized chest X-ray image and CT head Image. There are Extraction, Thresholding, Region G rowing, Split-Merge and Relaxation in feature extraction technique. In this study, Region Growing System was realized and Fuzzy Set Theory was applied in order to extract the vague region which the conventional method has difficulties in extracting. The performance of proposed algorithm was proved by being applied to chest X-ray image and CT head image.

• Proceedings of the Korean Society of Medical Physics Conference
• /
• 2002.09a
• /
• pp.442-445
• /
• 2002

We present an algorithm for automatic anatomically adaptive image enhancement of digital chest radiographs. Chest images were exposed using digital radiography system with a 0.143 mm pixel pitch, l4-bit gray levels, and 3121 ${\times}$ 3121 matrix size. A chest radiograph was automatically divided into two classes (lung field and mediastinum) by using a maximum likelihood method. Each pixel in an image was processed using fuzzy domain transformation and enhancement of both the dynamic range and local gray level variations. The lung fields were enhanced appropriately to visualize effectively vascular tissue, the bronchus, and lung tissue, etc as well as pneumothorax and other lung diseases at the same time with the desired mediastinum enhancement. A prototype implementation of the algorithm is undergoing trials in the clinical routine of radiology department of major Korean hospital.

• Journal of radiological science and technology
• /
• v.40 no.2
• /
• pp.179-186
• /
• 2017

Purpose of this study is present the normal range of cardiac size and cardiothoracic ratio according to patient position(chest PA and AP) and age of Korean adult male on digital chest X - ray, And to propose a mutually compatible conversion rate. 1,024 males were eligible for this study, among 1,300 normal chest patients who underwent chest PA and low-dose CT examinations on the same day at the 'S' Hospital Health Examination Center in Seoul From January to December 2014. CS and CTR were measured by Danzer (1919). The mean difference between CS and CTR was statistically significant (p<0.01) in Chest PA (CS 135.48 mm, CTR 43.99%) and Chest AP image (CS 155.96 mm, CTR 51.75%). There was no statistically significant difference between left and right heart in chest PA and AP images (p>0.05). CS showed statistically significant difference between Chest PA (p>0. 05) and Chest AP (p<0.05). The thorax size and CTR were statistically significant (p<0.01) in both age and chest PA and AP. Result of this study, On Chest AP image CS was magnified 15%, CTR was magnified 17% compare with Chest PA image. CS and CTR were about 10% difference by changing posture at all ages.

• Journal of the Korean Institute of Telematics and Electronics B
• /
• v.31B no.8
• /
• pp.160-171
• /
• 1994

The wide dynamic range and severely attenuated contrast in mediastinal area appearing in typical chest radiographs have often caused difficulties in effective visualization and diagnosis of lung diseases. This paper proposes a new adaptive image enhancement technique which potentially solves this problem and there by improves observer performance through image processing. In the proposed method image processing is applied to the chest radiograph with different processing parameters for the lung field and mediastinum adaptively since there are much differences in anatomical and imaging properties between these two regions. To achieve this the chest radiograph is divided into the lung and mediastinum by gray level thresholding using the cumulative histogram and the dynamic range compression and local contrast enhancement are carried out selectively in the mediastinal region. Thereafter a gray scale transformation is performed considering the JND(just noticeable difference) characteristic for effective image displa. The processed images showed apparenty improved contrast in mediastinum and maintained moderate brightness in the lung field. No artifact could be observed. In the visibility evaluation experiment with 5 radiologists the processed images with better visibility was observed for the 5 important anatomical structures in the thorax.

• Journal of Biomedical Engineering Research
• /
• v.44 no.4
• /
• pp.293-301
• /
• 2023

Scoliosis is a three-dimensional deformation of the spine that is a deformity induced by physical or disease-related causes as the spine is rotated abnormally. Early detection has a significant influence on the possibility of nonsurgical treatment. To train a deep learning model with preprocessed images and to evaluate the results with and without data augmentation to enable the diagnosis of scoliosis based only on a chest X-ray image. The preprocessed images in which only the spine, rib contours, and some hard tissues were left from the original chest image, were used for learning along with the original images, and three CNN(Convolutional Neural Networks) models (VGG16, ResNet152, and EfficientNet) were selected to proceed with training. The results obtained by training with the preprocessed images showed a superior accuracy to those obtained by training with the original image. When the scoliosis image was added through data augmentation, the accuracy was further improved, ultimately achieving a classification accuracy of 93.56% with the ResNet152 model using test data. Through supplementation with future research, the method proposed herein is expected to allow the early diagnosis of scoliosis as well as cost reduction by reducing the burden of additional radiographic imaging for disease detection.

• Korean Journal of Digital Imaging in Medicine
• /
• v.8 no.1
• /
• pp.27-32
• /
• 2006

The rapid development in digital acquisition technology in radiography has not been accompanied by information regarding optimum radiolographic technique for use with an amorphus silicon flat panel detector. The purpose of our study was to compared imaging characteristics and image quality of an amorphus silicon flat panel detectors for digital chest radiography. All examinations were performed by using an amorphus silicon flat panel detector. Chest radiographs of an chest phantom were obtained with peak kilovoltage values of 60$\sim$150 kVp. Published data ell the effect of x-ray beam energy on imaging characteristics and image qualify when using an amorphus silicon flat panel detector. It is important that radiographers are aware of optimum kVp selection for an amorphus silicon flat panel detector system, particularly for the commonly performed chest examination.