• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.12
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• pp.6066-6071
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• 2013

This paper proposes a calibration method for a freehand 3-D ultrasound system in medical robotic research. The calibration block with six wires was designed to set the fixed target points. The positions of the ultrasound probe and calibration block were measured using an optical tracker. The relationship between the position of the ultrasound probe and the pixel coordinates in the images was derived using a calibration process. The scaling matrix was also calculated. The experimental results showed that the proposed method could find solutions using a simple least square method from one or multiple ultrasound images.

• Journal of Korean Neurosurgical Society
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• v.62 no.1
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• pp.10-26
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• 2019

Magnetic resonance-guided focused ultrasound (MRgFUS) is an emerging new technology with considerable potential to treat various neurological diseases. With refinement of ultrasound transducer technology and integration with magnetic resonance imaging guidance, transcranial sonication of precise cerebral targets has become a therapeutic option. Intensity is a key determinant of ultrasound effects. High-intensity focused ultrasound can produce targeted lesions via thermal ablation of tissue. MRgFUS-mediated stereotactic ablation is non-invasive, incision-free, and confers immediate therapeutic effects. Since the US Food and Drug Administration approval of MRgFUS in 2016 for unilateral thalamotomy in medication-refractory essential tremor, studies on novel indications such as Parkinson's disease, psychiatric disease, and brain tumors are underway. MRgFUS is also used in the context of blood-brain barrier (BBB) opening at low intensities, in combination with intravenously-administered microbubbles. Preclinical studies show that MRgFUS-mediated BBB opening safely enhances the delivery of targeted chemotherapeutic agents to the brain and improves tumor control as well as survival. In addition, BBB opening has been shown to activate the innate immune system in animal models of Alzheimer's disease. Amyloid plaque clearance and promotion of neurogenesis in these studies suggest that MRgFUS-mediated BBB opening may be a new paradigm for neurodegenerative disease treatment in the future. Here, we review the current status of preclinical and clinical trials of MRgFUS-mediated thermal ablation and BBB opening, described their mechanisms of action, and discuss future prospects.

• The Korean Journal of Pain
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• v.24 no.2
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• pp.115-118
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• 2011

Meralgia paresthetica is a rarely encountered sensory mononeuropathy characterized by paresthesia, pain or sensory impairment along the distribution of the lateral femoral cutaneous nerve (LFCN) caused by entrapment or compression of the nerve as it crossed the anterior superior iliac spine and runs beneath the inguinal ligament. There is great variability regarding the area where the nerve pierces the inguinal ligament, which makes it difficult to perform blind anesthetic blocks. Ultrasound has developed into a powerful tool for the visualization of peripheral nerves including very small nerves such as accessory and sural nerves. The LFCN can be located successfully, and local anesthetic solution distribution around the nerve can be observed with ultrasound guidance. Our successfully performed ultrasound-guided blockade of the LFCN in meralgia paresthetica suggests that this technique is a safe way to increase the success rate.

• Clinical and Experimental Pediatrics
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• v.45 no.9
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• pp.1120-1125
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• 2002

Purpose : Percutaneous cannulation of the central vein in children and infants may be technically difficult and can cause serious complications. There are many techniques to improve the success rate and to decrease the complications in central vein cannulation. This study was undertaken to determine whether audible Doppler guidance can help operators improve the results of central vein cannultion in pediatric ICU. Methods : A total of 46 central vein cannulations were performed using audible Doppler guidance technique. Using an 8-MHz Doppler ultrasound device(Pocket-Dop II. iMex. USA), the artery and the vein were identified by their characteristic Doppler sounds. Results : There was a total of 46 patients with 20 boys and 26 girls, respectively. The mean age was $3years{\pm}45months$(range : 1-156 months). The number of infants was 18 and the mean age was $6.3{\pm}3.8$ months(range : 1-12 months). The most common site of central vein cannulation was the right internal jugular vein(63%). The cannulation was successful in 44 out of 46 procedures(96%). The success rate at the first attempt was 59% with 48% in the patients who had the history of previous cannulation and 70% in the patients who did not, respectively. The success rate in infants was 94%(17 out of 18). The average access time was $5.2{\pm}8.3$ minutes in children contrary to $7.5{\pm}10.3$ minutes in infants. There were no serious complications, but six patients had complications including four hematoma, one arterial puncture, and one pneumothorax. Conclusion : This central vein cannulation using Doppler guidance may improve the success rate of central vein cannulation and decrease the development of serious complications in infants and children.

• Progress in Medical Physics
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• v.33 no.4
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• pp.37-52
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• 2022

Over the past decades, radiation therapy combined with imaging modalities that ensure optimal image guidance has revolutionized cancer treatment. The two major purposes of using imaging modalities in radiotherapy are to clearly delineate the target prior to treatment and set up the patient during radiation delivery. Image guidance secures target position prior to and during the treatment. High quality images provide an accurate definition of the treatment target and the possibility to reduce the treatment margin of the target volume, further lowering radiation toxicity and improving the quality of life of cancer patients. In this review, the various types of image guidance modalities used in radiation therapy are distinguished into ionized (kilovoltage and megavoltage image) and nonionized imaging (magnetic resonance image, ultrasound, surface imaging, and radiofrequency). The functional aspects, advantages, and limitation of imaging using these modalities are described as a subsection of each category. This review only focuses on the technological viewpoint of these modalities and any clinical aspects are omitted. Image guidance is essential, and its importance is rapidly increasing in modern radiotherapy. The most important aspect of using image guidance in clinical settings is to monitor the performance of image quality, which must be checked during the periodic quality assurance process.

• Journal of Korean Neurosurgical Society
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• v.55 no.6
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• pp.383-386
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• 2014

Objective : Symptomatic thoracic disc herniation often requires prompt surgical treatment to prevent neurological deterioration and permanent deficits. Anterior approaches offer direct visualization and access to the herniated disc and anterior dura but require access surgeons and are often associated with considerable postoperative pain and pulmonary complications. A disadvantage with using posterior approaches in the setting of central calcified thoracic disc herniation however, has been the limited visualization of anterior dura and difficulty to accurately assess the extent of decompression. Methods : We report our experience with intraoperative ultrasound (US) guidance during a modified posterior transpedicular approach for removal of a central calcified thoracic disc herniation with a review of pertinent literature. Results : The herniated thoracic disc was successfully removed with posterior approach with the aid of intraoperative US. The patient had significant neurological improvement at three months follow-up. Conclusion : Intraoperative ultrasound is a simple yet valuable tool for real-time imaging during transpedicular thoracic discectomy. Visualization provided by intraoperative US increases the safety profile of posterior approaches and may make thoracotomy unnecessary in a selected group of patients, especially when a patient has existing pulmonary disease or is otherwise not medically fit for the transthoracic approach.

• Korean Journal of Veterinary Research
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• v.39 no.6
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• pp.1210-1217
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• 1999

This study was carried out to develop a newly designed ovum pick-up(OPU) instrument for ultrasound-guided transvaginal follicular aspiration in cows. This new instrument consists of out- & inner-layer stainless pipes and a grip with a trigger(hand) switch. Some gauge types of disposable needles and tubes can be attached to this inner pipe. With this instrument, while grasping an ovary with one hand, the other hand can handle in apiration and vacuum on/off with the least assitant's help. With this instrument the mean recovery rate of bovine follicular oocytes was 45.2%. In recovered oocytes, usable oocytes(Grade I & II) were 30.4% and this rate meant 1.4 oocytes per ovary. For 30 days after initial aspiration with this instrument, some adverse effects such as adhesion, hemorrhage, hematoma and other mass formation in/with ovaries were also examined by rectal examination, ultrasonographic and endoscopic images. Adhesion was found in one ovary 1 week after aspiration, and hemorrhagic lesion was found 1-2 days and petechia were found 3-5 days after aspiration and there was no remarkable adverse effects. It was found that this instrument could be applicable and safe for ovum pick-up in cows.

• The Journal of the Acoustical Society of Korea
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• v.39 no.1
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• pp.16-23
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• 2020

In High-Intensity Focused Ultrasound (HIFU) treatment, effective localization of HIFU focus is important for developing a safe treatment plan. While Magnetic Resonance Imaging guided HIFU (MRIgHIFU) can visualize the ultrasound path during the treatment for localizing HIFU focus, it is challenging in ultrasound imaging guided HIFU (USIgHIFU). In the present study, a real-time ultrasound beam visualization technique capable of localizing HIFU focus is presented for USIgHIFU. In the proposed method, a short pulse, with the same center frequency of an imaging ultrasound transducer below the regulated acoustic intensity (i.e., Ispta < 720 mW/㎠), was transmitted through a HIFU transducer whereupon backscattered signals were received by the imaging transducer. To visualize the HIFU beam path, the backscattered signals underwent dynamic receive focusing and subsequent echo processing. From in vitro experiments with bovine serum albumin gel phantoms, the HIFU beam path was clearly depicted with low acoustic intensity (i.e., Ispta of 94.8 mW/㎠) and the HIFU focus was successfully localized before any damages were produced. This result indicates that the proposed ultrasound beam path visualization method can be used for localizing the HIFU focus in real time while minimizing unwanted tissue damage in USIgHIFU treatment.

• Journal of Embryo Transfer
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• v.12 no.2
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• pp.211-218
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• 1997

This experiment was carried out to develop the anesthetic methods for ultrasonography and a new simplified disposable needle guidance device for ovum pick-up(OPU) in cows. Three different anesthetic methods were applied as. 1) epidural analgesia only with 2% lidocaine(20~30 ml), 2) epidural analgesia with 2% under general sedation with xylazine, 3) epidural analgesia with 2% lidocaine under general sedation with detomidine. We evaluated the anesthetic effects with items such as relaxation of anal sphincter, tail movement and rectal wall, retractability of both ovaries, additional anesthesia and possibility of OPU. Through this experiment, the above three anesthetic methods were applicable to OPU, but the epidural anlagesia under general sedation with detomldine was most effective for OPU. We developed a new disposable needle guidance device with stainless steel tube. With this, disposable needles can be easily attatchable to any other intravaginal probes. And also, it was found to he practical, economic and effective for OPU with the recovery rate of 51.2%.

• The Korean Journal of Pain
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• v.21 no.1
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• pp.57-61
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• 2008

Background: Shoulder joint injection is currently performed under fluoroscopic or computed tomography scan guidance. We performed this study to determine if an ultrasound guided shoulder joint injection through rotator cuff interval would have clinical usefulness. Methods: A total of 17 volunteers [12 women, 5 men; mean age 28 yr (23-32 yr)] received shoulder joint injection under multilinear ultrasound (5-10 MHz). Volunteers were positioned supinely on a table with their arm in a neutral position. The anterior shoulder region of the patient was sterilized using povidone iodine. A 24 gauge needle was introduced and directly visualized in real time as it passed obliquely from the skin surface to the inferior space of the biceps tendon. If there was little or no resistance to the injection, a contrast media (omnipaque) was injected and checked fluoroscopically. Results: Ultrasound guided shoulder joint injection through rotator cuff interval was successful in all cases. The average time taken for the procedure was $27.5{\pm}16.5sec$. The vertical distance from skin to the inferior space of the biceps tendon was $1.6{\pm}0.4cm$ and the distance of needle from the skin to the inferior space of biceps tendon was $2.8{\pm}0.6cm$. The procedure was well tolerated by all volunteers. Conclusions: Ultrasound guided shoulder joint injection through rotator cuff interval is an effective, rapid, and easy-to-perform injection technique. Ultrasound guided injection enables exact needle placement and avoids the use of both ionizing radiation and iodinated contrast material.