• Journal of the Korean Society of Radiology
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• v.16 no.1
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• pp.45-51
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• 2022

This study compared DLP values along with phantom entrance surface doses and the image quality of chest CT scans made using a Care Dose 4D+Care kV System, scans that are made using only the Care Dose 4D function, and scans that are made with changes made by applying 80 kVp, 100 kVp, 120 kVp, and 140 kVp to the Care Dose 4D and tube voltage to search for methods to maintain the highest image quality with minimal patient doses. It was shown that DLP values decreased 6.727% when scans were taken with Chest Care Dose 4D + Care kV semi 100 and 6.481% when scans were taken with Chest Care Dose 4D + Care kV. With Chest Non as a standard, skin surface doses decreased 16.519% when scans were taken with Chest Care Dose 4D + Care kV semi 100 and 15.705% when scans were taken with Chest Care Dose 4D + Care kV. With comparisons of image quality, when comparisons were made with Chest Non, comparisons made of SNR values and CNR values in all scanning conditions including Care Dose 4D + Care kV showed that there were no significant differences at P>0.05. Imaging using Chest Care Dose 4D + Care kV in chest CT showed that exposure doses decreased similarly to result values gained from the best conditions through manual adjustments of kV and mAS, and there were no significant differences in image SNR and CNR. If the Chest Care Dose 4D + Care kV function is used, image quality is maintained and patient exposure to radiation can be reduced.

• Journal of the Korean Society of Radiology
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• v.17 no.2
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• pp.207-213
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• 2023

Computed tomography (CT) images are used as the basis for proton Bragg peak position estimation and treatment plan simulation. During the Hounsfield Unit (HU) based proton stopping power ratio (SPR) estimation, small differences in the patient's density and elemental composition lead to uncertainty in the Bragg peak positions along the path of the proton beam. In this study, we investigated the potential of dual-energy computed tomography image-based proton SPRs prediction accuracy to reduce the uncertainty of Bragg peak position prediction. Single- and dual-energy images of an electron density phantom (CIRS Model 062M electron density phantom, CIRS Inc., Norfolk, VA, USA) were acquired using a computed tomography system (Somatom Definition AS, Siemens Health Care, Forchheim, Germany) to estimate the SPRs of the proton beam. To validate the method, it was compared to the SPRs estimated from standard data provided by the National Institute of Standards and Technology (NIST). The results show that the dual-energy image-based method has the potential to improve accuracy in predicting the SPRs of proton beams, and it is expected that further improvements in predicting the position of the proton's Bragg peak will be possible if a wider variety of substitutes with different densities and elemental compositions of the human body are used to predict the SPRs.

• Journal of the Korean Society of Radiology
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• v.17 no.3
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• pp.423-431
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• 2023

The purpose of this study is to analyze the factors affecting the classification of the severity of contrast media side effects based on the patient's body information using artificial intelligence techniques to be used as basic data to reduce the degree of contrast medium side effects. The data used in this study were 606 examiners who had no contrast medium side effects in the past history survey among 1,235 cases of contrast medium side effects among 58,000 CT scans performed at a general hospital in Seoul. The total data is 606, of which 70% was used as a training set and the remaining 30% was used as a test set for validation. Age, BMI(Body Mass Index), GFR(Glomerular Filtration Rate), BUN(Blood Urea Nitrogen), GGT(Gamma Glutamyl Transgerase), AST(Aspartate Amino Transferase,), and ALT(Alanine Amiono Transferase) features were used as independent variables, and contrast media severity was used as a target variable. AUC(Area under curve), CA(Classification Accuracy), F1, Precision, and Recall were identified through AdaBoost, Tree, Neural network, SVM, and Random foest algorithm. AdaBoost and Random Forest show the highest evaluation index in the classification prediction algorithm. The largest factors in the predictions of all models were GFR, BMI, and GGT. It was found that the difference in the amount of contrast media injected according to renal filtration function and obesity, and the presence or absence of metabolic syndrome affected the severity of contrast medium side effects.

• Journal of the Korean Society of Radiology
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• v.17 no.3
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• pp.343-350
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• 2023

Based on Lung CT Screening Reporting and Data System (Lung-RADS), which has been used to standardize reading for lung cancer screening since November 2016, the types and frequency of "S" modifier findings other than lung cancer were analyzed. As a result of this study, 360 cases (35.19%) of "S" modifier were found in 1,023 subjects, and the most frequent diseases were coronary calcification and emphysema, 145 (14.17%) of coronary calcification and 138 (13.49%) of emphysema, indicating that the discovery rate was very high compared to other findings. In addition, it was found to be highly associated with the duration of smoking, and in the case of coronary calcification, 9 cases (5.73%) were found in the non-smokers group A, 23 cases (11.44%) within 10 years of smoking, 39 cases (13.68%) in the C group within 20 years of smoking, and 31% of the E group over 30 years of smoking. In addition to coronary calcification and emphysema, abnormal findings of pneumonia, lung epilepsy, and mediastinal disease were also found to be p<0.05 as a result of the analysis of the association with the smoking period, indicating that the smoking period was affected.

• Journal of the Korean Society of Radiology
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• v.17 no.5
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• pp.693-699
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• 2023

Ultrasound is widely used in the medical field for non-destructive and non-invasive disease diagnosis. In order to improve the disease diagnosis accuracy of diagnostic medical images, improving spatial resolution is a very important factor. In this study, we aim to model the super resolution convolutional neural network (SRCNN) algorithm in ultrasound images and analyze its applicability in the medical diagnostic field. The study was conducted as an experimental study using Field II simulation and open source clinical liver hemangioma ultrasound imaging. The proposed SRCNN algorithm was modeled so that end-to-end learning can be applied from low resolution (LR) to high resolution. As a result of the simulation, we confirmed that the full width at half maximum in the phantom image using a Field II program was improved by 41.01% compared to LR when SRCNN was used. In addition, the peak to signal to noise ratio (PSNR) and structural similarity index (SSIM) evaluation results showed that SRCNN had the excellent value in both simulated and real liver hemangioma ultrasound images. In conclusion, the applicability of SRCNN to ultrasound images has been proven, and we expected that proposed algorithm can be used in various diagnostic medical fields.

• Journal of the Korean Society of Radiology
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• v.17 no.6
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• pp.993-999
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• 2023

Bio materials of fibrinogen and collagen are widely used in tissue regeneration engineering. In this study, I aim to create a new dual-structure support using these two materials. Strategically, tissue regeneration takes priority over blood vessel regeneration, so by forming a fibrinogen support that helps blood vessel formation on the outside of the double support and placing collagen, which is more effective in tissue regeneration, in the center, a synergistic effect in new tissue regeneration is expected. Although these two materials have been used interchangeably in previous studies, there has been no report yet on making a support through the formation of a support structure for the core system. Therefore, the core of this study, the double scaffold, is to propose a method for manufacturing a core structure with a collagen scaffold on the inside and fibrinogen on the outside. The experimental results showed that the fibrinogen located on the outside of the scaffold resulted in rapid biodegradation and drug release due to strategic biodegradation of the dual structure scaffold. On the other hand, collagen scaffolds were found to be able to maintain drug release time relatively longer than fibrinogen scaffolds. In conclusion, it is believed that applying the method of creating a double scaffold will have a synergistic effect on defective tissue regeneration.

• Journal of the Korean Society of Radiology
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• v.17 no.7
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• pp.1157-1164
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• 2023

This study measures the additional dose for each treatment area using kV X-ray based OBI (On-Board Imager) and CBCT (Cone-Beam CT), which have excellent spatial resolution and contrast, and evaluates the adequacy and stability of radiation management aspects of IGRT. The subjects of the experiment were examined with OBI and CBCT attached to a linear accelerator (Clinac IX), and ring-shaped Halcyon CBCT under imaging conditions for each treatment area, and the dose at the center was measured using an ion chamber. OBI single fraction dose was measured as 0.77 mGy in the head area, 3.04 mGy in the chest area, and 7.19 mGy in the pelvic area. The absorbed doses from the two devices, Clinac IX CBCT and Halcyon CBCT, were measured to be similar in the pelvic area, at 70.04 mGy and 70.45 mGy. and in chest CBCT, the Clinac IX absorbed dose (70.05 mGy) was higher than the Halcyon absorbed dose (21.01 mGy). The absorbed dose to the head area was also higher than that of Clinac IX (9.08 mGy) and Halcyon (5.44 mGy). In kV X-ray-based IGRT, additional radiation exposure due to photoelectric absorption may affect the overall volume of the treatment area, and caution is required.

• Journal of the Korean Society of Radiology
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• v.17 no.7
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• pp.1025-1031
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• 2023

We aimed to evaluate the radiation dose and image quality by changing the Scout view voltage in low-dose chest CT (LDCT) and applying scan parameters such as AEC (auto exposure control) and ASIR (adaptive statistical iterative reconstruction) to find the optimal protocol. Scout view voltage was varied at 80, 100, 120, 140 kV and after measuring the dose 5 times using the existing low-dose chest CT protocol, the appropriate kV was selected for the study using the Dose report provided by the equipment. After taking a basic LDCT shot at 120 kV, 30 mAs, ASIR 50% was applied to this condition. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were assessed by measuring Background noise (B/N). For dose comparison, CTDI_vol and DLP provided by the equipment were compared and analyzed using the formulas. The results indicated that the protocol of scout 140 + LDCT + ASIR 50 + AEC reduced radiation exposure and improved image quality compared to traditional LDCT, providing an optimal protocol. As demonstrated in the experiment, LDCT screenings for asymptomatic normal individuals are crucial, as they involve concerns over excessive radiation exposure per examination. Therefore, applying appropriate parameters is important, and it is expected to contribute positively to the public health in future LDCT based health screenings.

• Journal of the Korean Society of Radiology
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• v.17 no.5
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• pp.633-640
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• 2023

With the recent development of static and dynamic modulated brachytherapy methods in brachytherapy, which use radiation shielding to modulate the dose distribution to deliver the dose, the amount of parameters and data required for dose calculation in inverse treatment planning and treatment plan optimization algorithms suitable for new directional beam intensity modulated brachytherapy is increasing. Although intensity-modulated brachytherapy enables accurate dose delivery of radiation, the increased amount of parameters and data increases the elapsed time required for dose calculation. In this study, a GPU-based CUDA-accelerated dose calculation algorithm was constructed to reduce the increase in dose calculation elapsed time. The acceleration of the calculation process was achieved by parallelizing the calculation of the system matrix of the volume of interest and the dose calculation. The developed algorithms were all performed in the same computing environment with an Intel (3.7 GHz, 6-core) CPU and a single NVIDIA GTX 1080ti graphics card, and the dose calculation time was evaluated by measuring only the dose calculation time, excluding the additional time required for loading data from disk and preprocessing operations. The results showed that the accelerated algorithm reduced the dose calculation time by about 30 times compared to the CPU-only calculation. The accelerated dose calculation algorithm can be expected to speed up treatment planning when new treatment plans need to be created to account for daily variations in applicator movement, such as in adaptive radiotherapy, or when dose calculation needs to account for changing parameters, such as in dynamically modulated brachytherapy.

• Journal of the Korean Society of Radiology
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• v.18 no.1
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• pp.1-9
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• 2024

Proton therapy is known for its superior treatment method due to Bragg peak. To enhance the therapeutic effects of protons, research has been conducted on distributing gold nanoparticles within tumors to increase the absorbed dose. While previous studies focused on handling gold nanoparticles at micrometer and nonometer scale, this study proposes a method to computationally estimate the effect of gold nanoparticles at the millimeter scale. The Geant4 toolkit was applied to computational modeling. Assuming a uniform distribution of water, similar to the human body, and gold nanoparticles, the concentration of gold nanoparticles was adjusted using density ratios. When the density ratio was 5%, the gain in absorbed energy due to gold nanoparticles was nearly twice that of the pure water phantom at the Bragg peak. As the density ratio increased, the gain in absorbed energy linearly increased. When gold nanoparticles were distributed in only one voxel at the Bragg peak, the energy of the protons affected only the neighboring voxels. However, in cases where gold nanoparticles were distributed over a wide area, the volume showing 95% of the maximum absorbed energy (9.46 keV) for the pure water phantom (9.95 keV) exhibited an improvement in absorbed energy over a region 16 times larger, and this region increased as the density ratio increased. Further research is needed to quantify the relationship between the density ratio of gold nanoparticles and the relative biological effect (RBE) in the millimeter scale.