• Korean Journal of Digital Imaging in Medicine
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• v.16 no.1
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• pp.13-19
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• 2014

Purpose: FLAIR image is beneficial for the diagnosis of various bran diseases including ischemic CVS, brain tumors and infections. However the border between the legion of brain metastasis and surrounding edema may not be clear. Therefore, this study aims to investigate the practical benefits of delayed imaging by comparing the image from a patient with brain metastasis before a contrast enhancement and the image 10 minutes after a contrast enhancement. Materials and methods: Of the 92 people who underwent MRI brain metastases in suspected patients 13 people in three patients there is no video to target the 37 people confirmed cases, and motion artifacts brain metastases in our hospital June-December 2013, 18 people measurement position except for the three incorrect patient (male: 11 people, female: 7 people, average age: 60 years) in the target, test equipment, 3.0T MR System (ACHIEVA Release, Philips, I was 8ChannelSENSE Head Coil use Best, and the Netherlands). TR 11000 ms, TE 125 ms, TI2800 ms, Slice Thickness 5 mm, gap 5 mm, is a Slice number 21, the parameters of the 3D FFE, T2 FLAIR variable that was used to test, TR 8.1 ms, TE 3.7 ms, Slice number 240 I set to. The experiment was conducted by acquiring the FLAIR prior to contrast enhancement (heretofore referred to as Pre FLAIR), and acquiring the 3D FFE CE five minutes after the contrast enhancement, and recomposing the images in an axial plane of S/T 3mm, G 0mm (heretofore referred to as MPR TRA CE). Using the FLAIR 10 minutes after the contrast enhancement (heretofore referred to as Post FLAIR) and Pi-View, a retrospective study was conducted. Using MRIcro on the image of a patient confirmed for his diagnosis, the images before and after the contrast media, as well as the CNR and SNR of the MPR TRA CE images of the lesion and the site absent of lesion were compared and analyzed using a one-way analysis of variance. Results: CNR for Pre FLAIR and Post FLAIR were 34.35 and 60.13, respectively, with MPR TRA CE at 23.77 showing no significant difference (p<0.050). Post-experiment analysis shows a difference between Pre FLAIR and Post FLAIR in terms of CNR (p<0.050), but no difference in CNR between Post FLAIR and MPR TRA CE (p>0.050), indicating that the contrast media had an effect only on Pre FLAIR and Post FLAIR. The SNR for the normal site Pre FLAIR was 106.43, and for the lesion site 140.79. Post FLAIR for the normal site was 107.79, and for the lesion site 167.91. MPR TRA CE for the normal site was 140.23 and for the lesion site 183.19, showing significant difference (p<0.050), and post-experiment analysis shows that there was a difference in SNR only on the lesion sites for Pre FLAIR and Post FLAIR (p<0.050). There was no difference in SNR between the normal site and lesion site for Post FLAIR and MPR TRA CE, indicating no effect from the contrast media (p>0.050). Conclusions: This experiment shows that Post FLAIR has a higher contrast than Pre FLAIR, and a higher SNR for lesions, It was not not statistically significant and MPR TRA CE but CNR came out high. Inspection of post-contrast which is used in a high magnetic field is frequently used images of 3D T1 but, since the signal of the contrast medium and the blood flow is included, this method can be diagnostic accuracy is reduced, it is believed that when used in combination with Post FLAIR, and that can provide video information added to the diagnosis of brain metastases.

• Korean Journal of Digital Imaging in Medicine
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• v.14 no.2
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• pp.23-31
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• 2012

There are AEC mode and fix mode to exposure when the whole spine antero-posterior radiography is done by using DR equipment. This study compared the utility of fix mode to AEC mode, by evaluating organ dose and effective dose and by examining the quality of radiographic image. GE DEFINIUM 8000 and ART-200X Rando Phantom manufactured by Flukebiometical were used for this study. The Rando phantom was set in front of wall detector of X-rays equipment. AEC mode was set at 80kVp and Fix mode was set at 80kVp, 25mAs, 32mAs, 40mAs, and 50mAs. Whole spine AP image were aquired by combining C, T-L and L-S spine images obtained through 3 exposures. When obtaining C, T-L and L-S spine images, were checked for Air kerma (mGy) value calculated by UNFORS Xi meter attached at the phantom surface of center of radiation field. The effective and organ doses were compared by PCXMC program (PC-Based Monte Carlo Program). The quality of obtained radiographic image was evaluated visually by 3 radiologists using resolution chart. When the effective doses was calculated based on tissue weighting factor of ICRP-103, 1.278mSv was measured by AEC mode, and Fix mode measured 0.405mSv at 25mAs, 0.518mSv at 32mAs, 0.649mSv at 40mAs, and 0.810mSv at 50mAS. In addition, the organ dose measured with esposure at 25mAs by Fix mode was almost equivalent to the organ dose by AEC mode, at the esophagus, thyroid, oral mucosa, salivaly glands located at the cervical spine part, while the organ dose by Fix mode was in general lower than the organ dose by AEC mode at the other organs. When Fix mode at 32mAs, 40mAs, and 50mAs was compared to AEC mode for organ dose in 26 organs, AEC mode had higher measurement in 21 organs but not for than brain, trachea, thyroid, oral mucosa, and salivaly glands which are located at the cervical spine part. The image quality evaluated by resolution test chart was much higher with AEC mode than the quality with Fix mode at all exposure conditions. However, while the image quality of cervical spine exposured at 50mAs by Fix mode was lower than the quality of AEC mode, thoraco-lumbar spine and lumbo-sacral spine were calculated and the quality was similar to AEC mode. Scoliosis occurs mainly at thoraco-lumbar and lumbo-sacral spine, not at cervical spine. Compared to AEC mode, Using the appropriate protocol (80kVp, 50mAs) of fix mode for whole spine AP radiography was thought to be useful because the image quality of the thoraco-lumar and lumbo-sacral spine was similar on AEC mode, Also organ and effective doses can be decreased with Fix mode. Therefore, It is considered that fix mode can be used properly with AEC mode for whole spine AP radiography when considering patient's body posture.

• Investigative Magnetic Resonance Imaging
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• v.13 no.2
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• pp.152-160
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• 2009

Purpose : To intra-individually compare diagnostic accuracy of high-resolution contrast-enhanced magnetic resonance angiography (CE-MRA) with computed tomography angiography (CTA) and digital subtraction angiography (DSA) for the assessment of supraaortic steno-occlusive disease. Materials and Methods : Twenty-eight patients (20 men, 8 women, 53-79 years of age) underwent supraaortic CE-MRA, CTA and DSA. CE-MRA was performed on two 1.5T MR scanners (voxel dimension: $0.66{\times}0.66{\times}1.1$ or $1.2\;mm^3$), and CTA on 64-slice CT scanners (voxel dimension: $0.42{\times}0.42{\times}0.63\;mm^3$). All the three examinations were completed within 40 days (median 19 days; range 1-40 days). Retrospective evaluation and measurement of diameter of 6 extracranial and 9 intracranial arterial segments was done by 2 experienced radiologists. Results: A total of 420 arterial segments were examined by CE-MRA, CTA and DSA. On DSA, 34 stenoocclusive lesions were noted at extracranial (n= 19) and intracranial (n = 15) vessels. For extracranial stenosis greater than 70%, sensitivity, specificity, positive predictive value (PPV) and negative predictive values (NPV) were 94.7%, 98.7%, 90.0% and 99.3% on CE-MRA, and 94.7%, 99.3%, 94.7% and 99.3% on CTA. For intracranial stenosis greater than 50%, sensitivity; specificity, PPV and NPV were 93.3%, 98.3%, 77.8%and 99.6% on CE-MRA, and 86.7%, 97.9%, 72.2% and 99.1 % on CTA, with DSA as the standard of reference. Conclusion : Supraaortic CE-MRA is as reliable as CTA in depicting the arterial stenosis, and is effective in screening of significant stenosis of both extracranial and intracranial arterial stenosis.

• Fiber Technology and Industry
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• v.2 no.4
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• pp.490-508
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• 1998

One of the latest fields of research in the area of output devices is tactual display devices [13,31]. These tactual or haptic devices allow the user to receive haptic feedback output from a variety of sources. This allows the user to actually feel virtual objects and manipulate them by touch. This is an emerging technology and will be instrumental in enhancing the realism of wearable augmented environments for certain applications. Tactual displays have previously been used for scientific visualization in virtual environments by chemists and engineers to improve perception and understanding of force fields and of world models populated with the impenetrable. In addition to tactual displays, the use of wearable audio displays that allow sound to be spatialized are being developed. With wearable computers, designers will soon be able to pair spatialized sound to virtual representations of objects when appropriate to make the wearable computer experience even more realistic to the user. Furthermore, as the number and complexity of wearable computing applications continues to grow, there will be increasing needs for systems that are faster, lighter, and have higher resolution displays. Better networking technology will also need to be developed to allow all users of wearable computers to have high bandwidth connections for real time information gathering and collaboration. In addition to the technology advances that make users need to wear computers in everyday life, there is also the desire to have users want to wear their computers. In order to do this, wearable computing needs to be unobtrusive and socially acceptable. By making wearables smaller and lighter, or actually embedding them in clothing, users can conceal them easily and wear them comfortably. The military is currently working on the development of the Personal Information Carrier (PIC) or digital dog tag. The PIC is a small electronic storage device containing medical information about the wearer. While old military dog tags contained only 5 lines of information, the digital tags may contain volumes of multi-media information including medical history, X-rays, and cardiograms. Using hand held devices in the field, medics would be able to call this information up in real time for better treatment. A fully functional transmittable device is still years off, but this technology once developed in the military, could be adapted tp civilian users and provide ant information, medical or otherwise, in a portable, not obstructive, and fashionable way. Another future device that could increase safety and well being of its users is the nose on-a-chip developed by the Oak Ridge National Lab in Tennessee. This tiny digital silicon chip about the size of a dime, is capable of 'smelling' natural gas leaks in stoves, heaters, and other appliances. It can also detect dangerous levels of carbon monoxide. This device can also be configured to notify the fire department when a leak is detected. This nose chip should be commercially available within 2 years, and is inexpensive, requires low power, and is very sensitive. Along with gas detection capabilities, this device may someday also be configured to detect smoke and other harmful gases. By embedding this chip into workers uniforms, name tags, etc., this could be a lifesaving computational accessory. In addition to the future safety technology soon to be available as accessories are devices that are for entertainment and security. The LCI computer group is developing a Smartpen, that electronically verifies a user's signature. With the increase in credit card use and the rise in forgeries, is the need for commercial industries to constantly verify signatures. This Smartpen writes like a normal pen but uses sensors to detect the motion of the pen as the user signs their name to authenticate the signature. This computational accessory should be available in 1999, and would bring increased peace of mind to consumers and vendors alike. In the entertainment domain, Panasonic is creating the first portable hand-held DVD player. This device weight less than 3 pounds and has a screen about 6' across. The color LCD has the same 16:9 aspect ratio of a cinema screen and supports a high resolution of 280,000 pixels and stereo sound. The player can play standard DVD movies and has a hour battery life for mobile use. To summarize, in this paper we presented concepts related to the design and use of wearable computers with extensions to smart spaces. For some time, researchers in telerobotics have used computer graphics to enhance remote scenes. Recent advances in augmented reality displays make it possible to enhance the user's local environment with 'information'. As shown in this paper, there are many application areas for this technology such as medicine, manufacturing, training, and recreation. Wearable computers allow a much closer association of information with the user. By embedding sensors in the wearable to allow it to see what the user sees, hear what the user hears, sense the user's physical state, and analyze what the user is typing, an intelligent agent may be able to analyze what the user is doing and try to predict the resources he will need next or in the near future. Using this information, the agent may download files, reserve communications bandwidth, post reminders, or automatically send updates to colleagues to help facilitate the user's daily interactions. This intelligent wearable computer would be able to act as a personal assistant, who is always around, knows the user's personal preferences and tastes, and tries to streamline interactions with the rest of the world.

• Progress in Medical Physics
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• v.26 no.4
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• pp.280-285
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• 2015

In radiation therapy fields, a brachytherapy is a treatment that kills lesion of cells by inserting a radioisotope that keeps emitting radiation into the body. We currently verify the consistency of radiation treatment plan and dose distribution through film/screen system (F/S system), provide therapy after checking dose. When we check dose distribution, F/S systems have radiation signal distortion because there is low resolution by penumbra depending on the condition of film developed. In this study, We fabricated a $HgI_2$ Semiconductor radiation sensor for base study in order that we verify the real dose distribution weather it's same as plans or not in brachytherapy. Also, we attempt to evaluate the feasibility of QA system by utilizing and evaluating the sensor to brachytherapy source. As shown in the result of detected signal with various source-to-detector distance (SDD), we quantitatively verified the real range of treatment which is also equivalent to treatment plans because only the low signal estimated as scatters was measured beyond the range of treatment. And the result of experiment that we access reproducibility on the same condition of ${\gamma}$-ray, we have made sure that the CV (coefficient of variation) is within 1.5 percent so we consider that the $HgI_2$ sensor is available at QA of brachytherapy based on the result.

• The Korean Journal of Nuclear Medicine
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• v.34 no.3
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• pp.183-198
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• 2000

Purpose: The purpose of this study was to evaluate alterations of regional cerebral blood flow (CBF) and cerebrovascular reserve (CVR), and correlation between these alternations and cognitive dysfunction in patients with chronic traumatic brain injury (TBI) and normal brain MRI findings. Materials and Methods: Thirty TBI patients and 19 healthy volunteers underwent rest/acetazolamide brain SPECT using Tc-99m HMPAO. Korean-Wechsler Adult Intelligence scale test was also performed in the patient group. Statistical analysis was performed with statistical parametric mapping software (SPM'97) Results: CBF was diminished in the left hemisphere including Wernicke's area in all patients with lower verbal scale scores. In addition, a reduction in CBF in the right frontal, temporal and parietal cortices was related with depressed scores in information, digital span, arithmetic and similarities. In patients with lower performance scale scores, CBF was mainly diminished in the right hemisphere including superior temporal and supramarginal gyri, premotor, primary somatomotor and a part of prefrontal cortices, left frontal lobe and supramarginal gyrus. CVR was diminished in sixty-four Brodmann's areas compared to control. A reduction in CVR was demonstrated bilaterally in the frontal and temporal lobes in patients with lower scores in both verbal and performance tests, and in addition, both inferior parietal and occipital lobes in information subset. Conclusion: Alterations of CBF and CVR were demonstrated in the symptomatic TBI patients with normal MRI finding. These alterations were correlated with the change of intelligence, of which the complex functions are subserved by multiple interconnected cortical structures.

• Radiation Oncology Journal
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• v.28 no.3
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• pp.166-176
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• 2010

Purpose: To determine the appropriate prostate planning target volume (PTV) margins for 3-dimensitional (3D) conformal radiotherapy (CRT) and intensity-modulated radiation therapy (IMRT) patients treated with an endorectal balloon (ERB) under our institutional treatment condition. Materials and Methods: Patients were treated in the supine position. An ERB was inserted into the rectum with 70 cc air prior to planning a CT scan and then each treatment fraction. Electronic portal images (EPIs) and digital reconstructed radiographs (DRR) of planning CT images were used to evaluate inter-fractional patient's setup and ERB errors. To register both image sets, we developed an in-house program written in visual $C^{++}$. A new method to determine prostate PTV margins with an ERB was developed by using the common method. Results: The mean value of patient setup errors was within 1 mm in all directions. The ERB inter-fractional errors in the superior-inferior (SI) and anterior-posterior (AP) directions were larger than in the left-right (LR) direction. The calculated 1D symmetric PTV margins were 3.0 mm, 8.2 mm, and 8.5 mm for 3D CRT and 4.1 mm, 7.9 mm, and 10.3 mm for IMRT in LR, SI, and AP, respectively according to the new method including ERB random errors. Conclusion: The ERB random error contributes to the deformation of the prostate, which affects the original treatment planning. Thus, a new PTV margin method includes dose blurring effects of ERB. The correction of ERB systematic error is a prerequisite since the new method only accounts for ERB random error.

• Journal of Chest Surgery
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• v.41 no.4
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• pp.469-475
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• 2008

Background: Video-assisted thoracic sympathicotomy is a definitive minimally invasive treatment for axillary hyperhidrosis. Different techniques exist for controlling axillary hyperhidrosis, but they are temporary and expensive. We compared the results after using two different levels of sympathicotomy for treating axillary hyperhidrosis: T3-T4 and T4. Material and Method: Between June 2002 and May 2007, 30 patients with isolated axillary hyperhidrosis underwent either T3-T4 or T4 thoracoscopic sympathicotomy in the Department of Thoracic & Cardiovascular Surgery at Wonkwang University Hospital. The patients were divided into two groups. Group I (n=15) was composed of patients who underwent T3-T4 sympathicotomy (thermal ablation), and Group II (n=15) was composed of patients who underwent T4 sympathicotomy (thermal ablation). The procedures were bilateral and simultaneous, involving the use of two 2-mm trocars and a 0-degree 2-mm thoracoscope under general anesthesia with single endotracheal intubation. Outcome parameters included satisfaction rate of treatment, degree of compensatory sweating, and postoperative complications. Patients were interviewed by telephone regarding satisfaction and compensatory hyperhidrosis. Result: There were no differences in age between group I and group II. The mean follow-up for the T3-T4 group was $38.7{\pm}2.3$ months, and the mean follow-up for the T4 group was $18.7{\pm}3.6$ months. The immediate therapeutic success rate (within 2 weeks postoperative) was 100% in both groups, and there were no recurrences in either group during the long-term follow-up period. The satisfaction rate was higher (93.3%) in the T4 group than in the T3-T4 group (53.3%), and the incidence of compensatory hyperhidrosis was lower in the T4 group (6.7%) than in the T3-T4 group (46.7%). Postoperative complications included one mild pneumothorax and two instances of intercostal neuralgia. Digital infrared thermographic imaging (DITI) correlated well with postoperative satisfaction. Conclusion: Both techniques proved effective for controlling isolated axillary hyperhidrosis. The T4 group had a higher satisfaction rate and lower severity of compensatory hyperhidrosis. Hence, thermal ablation of the lower interganglionic fibers of the third thoracic sympathetic ganglion on the fourth rib is a more practical and minimally invasive treatment than is the T3-T4 surgical method, according to the degree of compensatory sweating in isolated axillary hyperhidrosis.

• Journal of Oral Medicine and Pain
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• v.34 no.3
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• pp.227-235
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• 2009

Many of the protective functions of saliva can be attributed to the biological, physical, structural, and rheological characteristics of salivary glycoproteins. Therefore, the development of ideal saliva substitutes requires understanding of the rheological as well as biological properties of human saliva. In the present study, we investigated the changes of salivary enzymatic activities by saliva substitutes and compared viscosity of saliva substitutes with human saliva. Five kinds of saliva substitutes such as Moi-Stir, Stoppers4, MouthKote, Saliva Orthana, and SNU were used. Lysozyme activity was determined by the turbidimetric method. Peroxidase activity was determined with an NbsSCN assay. $\alpha$-Amylase activity was determined using a chromogenic substrate, 2-chloro-p-nitrophenol linked with maltotriose. The pH values of saliva substitutes were measured and their viscosity values were measured with a cone-and-plate digital viscometer at six different shear rates. Various types of saliva substitutes affected the activities of salivary enzymes in different ways. Stoppers4 enhanced the enzymatic activities of hen egg-white lysozyme, bovine lactoperoxidase (bLP), and $\alpha$-amylase. Saliva Orthana and SNU inhibited bLP activity and enhanced $\alpha$-amylase activity. MouthKote inhibited $\alpha$-amylase activity. Moi-Stir inhibited the enzymatic activities of bLP and $\alpha$-amylase. The pH values were very different according to the types of saliva substitutes. Stoppers4, MouthKote, and Saliva Orthana showed lower values of viscosity at low shear rates and higher values of viscosity at high shear rates compared with unstimulated and stimulated whole saliva. Moi-Stir and SNU displayed much higher values of viscosity than those of natural whole saliva. Collectively, our results indicate that each saliva substitute has its own biological and rheological characteristics. Each saliva substitute affects the enzymatic activity of salivary enzyme and finally oral health in different ways.

• The Journal of Korean Society for Radiation Therapy
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• v.26 no.1
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• pp.77-81
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• 2014

Purpose : In the current whole brain Radiation Therapy, Optimold was used to immobilize the head. However, skin dose was increased about 22% due to the scattering radiation by the Optimold. Since the minimum dose causing cataracts was 2 Gy, it could be seen that the effects were large especially on the lens. Therefore, in the whole brain Radiation Therapy, it was to compare and to evaluate the lens absorbed dose according to the presence of Optimold in the eyeball part. Materials and Methods : In order to compare and to evaluate the lens absorbed dose according to the presence of Optimold in the eyeball part, the Optimold mask was made ??up to 5mm bolus on the part of the eye lens in the human model phantom (Anderson Rando Phantom, USA). In the practice treatment, to measure the lens dose, the simulation therapy was processed by placing the GafChromic EBT3 film under bolus, and after the treatment plan was set up through the treatment planning system (Pinnacle, PHILIPS, USA), the treatments were measured repeatedly three times in the same way. After removing the Optimold mask in the eyeball part, it was measured in the same way as above. After scanning the film and measuring the dose by using the Digital Flatbed Scanner (Expression 10000XL, EPSON, USA), the doses were compared and evaluated according to the presence of Optimold mask in the eyeball part. Results : When there was the Optimold mask in the eyeball part, it was measured at $10.2cGy{\pm}1.5$ in the simulation therapy, and at $24.8cGy{\pm}2.7$ in the treatment, and when the Optimold mask was removed in the eye part, it was measured at $12.9cGy{\pm}2.2$ in the simulation therapy, and at $17.6cGy{\pm}1.5$ in the treatment. Conclusion : In case of removing the Optimold mask in the eyeball part, the dose was increased approximately 3 cGy in the simulation therapy and was reduced approximately 7 cGy in the treatment in comparison to the case that the Optimold mask was not removed. During the whole treatment, since the lens absorbed dose was reduced about 27%, the chance to cause cataracts and side effects was considered to be reduced due to decrease of the absorbed dose to the eye lens which had the high sensitivity on the radiation.