• Proceedings of the Korean Society of Medical Physics Conference
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• 2003.09a
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• pp.41-41
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• 2003

Purpose: Even if the wedge filter is widely used for the radiation therapy to modify the photon beam intensity, the wedged photon beam dose calculation is not so easy. Radiation therapy planning systems (RTPS) have been used the empirical or semi-analytical methods such as attenuation method using wedge filter parameters or wedge filter factor obtained from measurement. However, these methods can cause serious error in penumbra region as well as in edge region. In this study, we propose the dose calculation algorithm for wedged field to minimize the error especially in the outer beam region. Materials and Method: Modified intensity by wedge filter was calculated using tissue-maximum ratio (TMR) and scatter-maximum ratio (SMR) of wedged field. Profiles of wedged and non-wedged direction was also used. The result of new dose calculation was compared with measurement and the result from attenuation method. Results: Proposed algorithm showed the good agreement with measurement in the high dose-gradient region as well as in the inner beam region. The error was decreased comparing to attenuation method. Conclusion: Although necessary beam data for the RTPS commissioning was increased, new algorithm would guarantee the improved dose calculation accuracy for wedged field. In future, this algorithm could be adopted in RTPS.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.6 no.2
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• pp.155-164
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• 2020

Polyethylene glycol (PEG) has been the most commonly used polymer for the past few decades in the field of biomedical applications due to its gold standard stealth effect. PEGylation of antibody-drug conjugates, liposomes, peptides, nanoparticles, and proteins is done to improve their pharmaceutical efficacy and pharmacokinetic properties. PEGylation of antibodies with various PEG linkers improves targeting ability by increasing the blood circulation time and thus enhances the biodistribution profiles. It also assists in minimizing the immediate capture by the reticuloendothelial system. In this review, we summarize the effect of PEG linkers in an antibody conjugation and their pharmacokinetics in the field of biomedical imaging.

• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.251.1-251.1
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• 2008

• Proceedings of the Korean Magnestics Society Conference
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• 2009.12a
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• pp.212-212
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• 2009

• Proceedings of the KSMRM Conference
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• 1999.11a
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• pp.92-92
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• 1999

• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.301.2-301.2
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• 2008

• Journal of Magnetics
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• v.19 no.1
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• pp.32-36
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• 2014

The purpose of this study was to investigate the effect of pulsed magnetic field (PMF) and low frequency low level laser (LFLLL) stimuli on acupoint LI4 (Hegu) using photoplethysmography (PPG). Our PMF system was designed to generate maximum intensity of 0.20 T at a transition time of 0.16 ms, with pulse intervals of 1 Hz. The diode laser with wavelength of 650 nm and power of 5 mW was also employed. It was observed the change of the pulsating blood volume through measuring PPG signals from both hands. These results imply that stimulating acupoint LI4 with PMF and LFLLL improves the circulation of peripheral vascular system. In particular, PMF stimulation brings a big improvement of the blood flow even with short term stimulation of 3-4 minutes compared to LFLLL stimulus.

• Journal of Biomedical Engineering Research
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• v.28 no.1
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• pp.102-107
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• 2007

In molecular imaging studies via magnetic resonance imaging, in vivo cell tracking is an important issue for the observation of cell therapy or disease behavior. High resolution imaging and longitudinal study are necessary to track the cell movement. Since the field inhomogeneity extends over several voxels, we have performed the numerical analysis using the sub-voxel method dividing a voxel of MR image into several elements and the information about the field inhomogeneity distribution around the micro-beads. We imbedded ferrite-composite micro-beads with the size of $20-150{\mu}m$ in the subject substituted for cells to induce local field distortion. In the phantom imaging with the isotropic voxel size of $200{\mu}m^3$, we could confirm the feasibility of sub-voxel tracking in a 3.0 T MRI.

• Proceedings of the KOSOMBE Conference
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• v.1998 no.11
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• pp.269-270
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• 1998

Image-guided surgery (IGS) system has become well known in the field of neurosurgery and spine surgery. A patient's anatomy is first registered to preoperatively acquired CT/ MRI data using the point matching algorithm. A magnetic field digitizer was used to measure the physical space data and the system was based on Workstation of Unix system. To evaluate the spatial accuracy of interactive IGS system, the phantom consisting of rods varied height and known location was used. The RMS error value between CT/MR images and real location was 3-4mm. For the more convenience of the surgery, we provide various image display modules.

• Journal of Magnetics
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• v.18 no.2
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• pp.188-191
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• 2013

The magnetic properties for sanal's mobility inside of the lymphatic primo vascular system, the so-called Kyungrak (or meridian) system, are investigated under a low static magnetic field with the anatomy technology and optical microscope. One sanal with a size of 1 ${\mu}m$ under microscope selected and separated from the primo vessels of the primo vascular system are observed in rabbits' lymphatic vessels around abdominal aorta and placed in PBS solution with petridish. The moving displacement of sanal versus the measuring time of 20 Oe below a magnetic field of 80 Oe is stronger in dominanting dependence according to the x-direction than y-direction.