Hyun Soo Lim

Evaluation of diagnostic medical exposure in Republic of Korea

National statistical data for diagnostic radiation exposure in Republic of Korea were collected from four public institutes and government agencies during the period 2006-2013. The data were pooled, reclassified and analysed. A total of 1574 million exposures occurred during the study period. To evaluate the effective diagnostic radiation exposure dose, the dose conversion factors developed by the Korea Food and Drug Administration were applied. The number of diagnostic radiation exposures was 197 million per year. The collective effective dose averaged 64 043 man Sv y(-1), and the annual per caput effective dose averaged 1.27 mSv. The annual per caput effective dose in 2013 was 1.54 mSv compared with 0.89 mSv in 2006, a marked increase of 73.9 % over the study period. These research data, compiled from reliable sources within the public health system of Republic of Korea, demonstrate a trend of increasing diagnostic radiation exposure and provide valuable information for further research.

GafChromic RTQA Film Dosimetry for Laser Beam with Photodynamic Therapy

Abstract: Purpose: The purposes of this study were to measure the dose distribution of Photodynamic ther-apy(PDT) laser with 635 nm wavelength using GafChromic film. Method & Result: We made each output 300 J bychanging mW and sec using the laser beam radiation mode such as C.W(Continuous Wave) mode, Pulse mode andBurst Pulse mode and measured the does at 0 mm and 5 mm of distance from optic fiber catheter end to the film,and at 5 mm distance by changing the angle of the end of the optic fiber catheter as 0 o and 0.5 o . The radiated filmwas scanned and OD(Optical Density) was compared. And two-dimensional isodose curves were obtained and theconsistency of shapes was compared. It was confirmed that there was consistency between optic density and thedose radiated on the film when we radiated GafChromic film by changing distance and angle of 300 J output in eachradiation mode coordinating mW and sec. Conclusion: In this study, we could identify the stability according tochanges in laser beam modes, changes in output according to distance, changes in uniformity according to angle, andbeam profiles using GafChromic film, and we could also get two-dimensional isodose curve. It was found that smallchange in the distance and angle that is made when optic fiber catheter was contacted on the treatment area did notmake big effects on the output of beam and the uniformity of dose, and it was also found that GafChromic film couldbe utilized for the purpose of QA of PDT laser beam.Key words: GafChromic film, change in radiation mode, beam profile, two-dimensional isodose curve

Reduction of thermal damage in photodynamic therapy by laser irradiation techniques

Abstract. General application of continuous-wave (CW) laser irradiation modes in photodynamic therapy can cause thermal damage to normal tissues in addition to tumors. A new photodynamic laser therapy system using a pulse irradiation mode was optimized to reduce nonspecific thermal damage. In in vitro tissue specimens, tissue energy deposition rates were measured in three irradiation modes, CW, pulse, and burst-pulse. In addition, methods were tested for reducing variations in laser output and specific wavelength shifts using a thermoelectric cooler and thermistor. The average temperature elevation per 10  J/cm2 was 0.27°C, 0.09°C, and 0.08°C using the three methods, respectively, in pig muscle tissue. Variations in laser output were controlled within ±0.2%, and specific wavelength shift was limited to ±3  nm. Thus, optimization of a photodynamic laser system was achieved using a new pulse irradiation mode and controlled laser output to reduce potential thermal damage during conventional CW-based photodynamic therapy.

Design and Evaluation of Excitation Light Source device for Fluorescence Endoscope

This study aims at designing and evaluating light source devices that can stably generate light with various wavelengths in order to make possible PDD using a photosensitizer and diagnosis using auto-fluorescence. The light source was a Xenon lamp and filter wheel, composed of an optical output control through Iris and filters with several wavelength bands. It also makes the inducement of auto-fluorescence possible because it is designed to generate a wavelength band of 380-420nm, 430-480nm, and 480-560nm. The transmission part of the light source was developed to enhance the efficiency of light transmission. To evaluate this light source, the characteristics of light output and wavelength band were verified. To validate the capability of this device as PDD, the detection of auto-fluorescence using mouse models was performed.

Estimation of Photon Distribution within Biological Tissue Using Monte Carlo Simulation

Recently, Photodynamic therapy (PDT) method becomes one of the methods to treat cancer using light. It is necessary to measure the light dosimetry in tissue to apply PDT for cancer to patient. To measure light dosimetry accurately, One must understand the light propagation in tissue and simulate with optical properties of target tissue. Optical coefficients are basically three interaction coefficients: absorption coefficient (μa), scattering coefficient (μs) and phase function [1-4]. It is very important to measure the correct optical properties in biological tissue to execute Monte Carlo simulation. If one want to perform with correct optical properties in simulation, he should have to measure the light doses in biological tissue. In this study, we simulated Monte Carlo simulation with multi-layered phantoms, having the optical properties in biological tissue, to evaluate the light fluence profile.

Engineering design process and comparison of multi wavelength real time auto-fluorescence and fluorescence imaging guide system irradiance with xenon lamps and light emitting diodes (LEDs) for open and laparoscopic cancer surgery

Background: Although considerable brainstorm has been known into Epstein-Barr virus EBV as an important etiologic factor in various tumors, virtually little is known about the relationship between EBV genes and leukemia. The actual cause of Leukemia, which is a serious cancer in Sudan, is still under scrutiny. Controversial hypotheses were proposed suggesting the role of physical as well as chemical and even biological factors as being responsible for Leukemia incidents. We hypothesized that EBV could be involved in the etiology of leukemia. We describe here the results of our attempt to find a possible link between leukemia and EBV . Methods: Real-time Polymerase Chain Reaction assay (q-PCR) has recently been used widely for detection of Cell-free EBVDNA in the plasma of patients with leukemia. To determine the possible correlation between plasma cell-free EBV DNA levels and the leukemia, we studied the plasma EBV DNA levels in patients with leukemia that were presented at Radiation and Isotope Centre Khartoum (RICK), Sudan during therapy. The concentrations of plasma cell-free EBV DNA of 128 leukemic patients, 17 patients with EBV-associated lymphoid malignancies during the course of therapy Burkitts lymphoma, Hodgkins disease, Nasopharyngeal carcinoma (NPC) as control positive and 15 healthy controls were determined by using the (q-PCR) assay with the PrimerDesign™ genesig quantification kit. Results: The results revealed that EBV DNA was detectable in a wide range of leukemia patients. Plasma EBV DNA was detected in 33/88 Acute lymphoblastic leukemia (ALL) patients 28/40 Chronic myelogenous leukemia (CML),15/17 patients with EBV-associated lymphoid malignancies, but not in any of 15 healthy control subjects. The median concentration of EBV DNA in leukemia and healthy control groups was 6561.00 and 0.00 copies/ml, respectively. Conclusion: Our findings provided evidence of the involvement of EBV in patients with leukemia. The results suggested that EBV DNA genome encoding the non-glycosylated membrane protein BNRF1 pl43 was observed in a significant proportion of patients with ALL. However, we could not exclude a correlation between these viral infections and later leukemogenesis in childhood ALL in Sudan.N ganglioside is tumor specific antigen from different cancers and it has been associated with bad prognosis. The epidermal growth factor receptor (EGFR) is an aggressive prognostic indicator in some tumors. Center of Molecular Immunology (CIM), Havana, Cuba has developed vaccines and monoclonal antibodies against these targets. Also, any evidences revealed a functional relationship between EGFR and NGcGM3 at the tumor cell membrane, suggesting a rational for exploring the therapeutic combinations of immunotherapies targeting them. However, limited evidence has been generated. We explored whether the survival and antimetastatic effect of passive anti-EGFR therapy (7A7 mAb; iv) would be modulated by the co-administration of NeuGcGM3/VSSP vaccine (sc), in two murine spontaneous lung metastasis models: Lewis lung carcinoma (3LL-D122) and mammary adenocarcinoma (4T1, orthotropic). Target combination therapy increased survival in two lung metastasis models, in comparison with monotherapy groups (n=10 in each group). Moreover, depletion of NK1.1+, CD4+ and CD8+ cells in vivo completely abrogated the increment in survival of the combination treatment group. Concomitantly, reduction of NGcGM3 ganglioside, Uroquinase Plasminogen Activator Receptor (uPAR) and α5β1integrin expression is leading the inhibition of pro-tumoral signaling by the activation of EGFR, FAk and Src molecules in this group. Combination treatment induces a stronger inhibition of the signaling cascades related to EGFR and NGcGM3 ganglioside at the tumor cell membrane. In summary, these two lung metastasis models are a good murine setting to validate the potential combination of NGcGM3 vaccines and anti-EGFR treatments and suggest the opportunity for cancer patients who overexpressed these two molecules.A is an essential element in the successful treatment of Acute Lymphoblastic Leukemia, the most common type of cancer affecting children. However, in about 5–10% of cases this treatment causes Acute Pancreatitis (AP) as a side-effect. In AP, a potentially fatal human disease, the inactive pancreatic pro-enzymes become active enzymes inside the pancreatic acinar cells, digesting the pancreas and its surroundings. Under physiological conditions intracellular calcium signaling and Mg-ATP level are the key elements needed for stimulant-evoked exocytotic enzyme secretion from pancreatic acinar cells. Physiological Ca2+ signals stimulate ATP production, whereas sustained global cytosolic Ca2+ elevations decrease ATP levels and cause necrosis leading to AP. Alcohol and gallstones are the major causes of the disease. We have investigated the mechanism by which L-Asparaginase evokes AP. For the first time, we have shown that like other pancreatitis-inducing agents, Asparaginase evoked excessive intracellular Ca2+ release followed by Ca2+ entry, decreased the intracellular ATP levels and reduced Ca2+ extrusion. The toxic Ca2+ signals induced by Asparaginase caused extensive cell necrosis. Our data indicate that the Asparaginase-induced pathology depends on protease activated receptor 2 and its inhibition prevented the toxic Ca2+ signals and necrosis. Inhibition of Ca2+ entry with GSK-7975A markedly reduced Asparaginase-induced cellular pathology. We have demonstrated a reduction in the intensity of Ca2+ extrusion due to the reduction in the intracellular ATP level limiting the energy supply to the Ca2+ ATPase in the plasma membrane. Supplementation of the medium with sodium pyruvate provided a similar degree of protection against pancreatic necrosis as PAR2 inhibition or GSK7579A. Ca2+ and ATP play key roles in Asparaginase-pancreatic pathology and therapeutic strategies must take both into account. We suggest that combined pharmacological control of intracellular calcium and ATP levels will prevent or alleviate AP and improve childhood cancer treatments..I of circulating tumour cells (CTCs) from peripheral blood has the potential to provide an easier ‘liquid biopsy’ than tumour tissue biopsies, to monitor disease progression and response to therapies at cell and molecular level. Previous studies on CTCs have mainly focused on the identification of cytokeratin (CK)+/CD45epithelial cells. However, epithelial to mesenchymal transition is a critical step for tumour metastasis. We optimised a size-based platform, Parsortix, for the isolation of CTCs with both epithelial and mesenchymal properties and developed a multiple FISH rehybridization method to analyse multiple genomic changes on the CTCs after immunofluorescence signals were completely striped. Three types of CD45potential circulating tumor cells, CK+/vimentin-, CK+/vimentin+ and CK-/vimentin+, were detected. Genomic alterations were detected in a similar large proportion of cells in all the three groups by analysing several genomic regions, indicating that the majority or all of those CK-/vimentin+/CD45-cells are circulating prostate cancer cells under epithelial to mesenchymal transition. In addition, the number of CK-/vimentin+/CD45CTCs correlated better with cancer progression features than CK+ CTCs. Therefore, we developed a novel CTC detection and genomic analysis approach, which can efficiently analyse both CK+ and CK-/vimentin+/CD45cancer CTCs. This greatly enhances our ability to investigate cancer metastasis process and using CTCs to monitor cancer progression and therapeutic response..

A Effect of Photo Dynamic Therapy for LAZER Wave Mode

US Food and Drug Administration (FDA) approved as a innovative cure for cancer, 1996. The effect is death of cancer cells through necrosis, apoptosis. Mainly the Continuous Wave mode (CW) use for PDT Laser. It sting, the question including itch, and etc. Reportedly, the increase of temperature with the perforated edema, ulcer, necrosis. The Thermal relaxation time and Oxygen recovery time is necessary. To give a normal oxygen recovery time of the cell, used Pulse mode. Progress, it was Burst Pulse mode when easing the thermal wake, the simplicity was secured, the PDT effect is good. Excepted in control group CW, Pulse, Burst pulse mode were incubated with various concentrations of 5-aminolevulinic acid hydrochloride (ALA-5). The tumor size reduction CW mode (44%), Pulse mode (48%), Burst pulse mode (53%) at 4 week after PDT with 0.3, 0.3, 0.3 mg/ml of ALA-5. After 4 hours, investigation of 100, 100, 100 J/cm laser irradiation. The pulse mode was superior in expirimental data analysis. And it was the Burst pulse mode edge head of a family effect.

Development of multiwavelength excitation light source for autofluorescence and photodynamic diagnosis systems

New design of the excitation light source that can stably generate light with center wavelengths of 450nm, 530nm, 632.8nm and white light for auto-fluorescence(AF) and photodynamic diagnosis(PDD) of cancer in clinics in a single system is presented in this study. The light source consists of Xenon Lamp (300W), light guide module including motorize filter wheel equipped with optical filters with corresponding to wavelength bands, servo motor, motorize iris, a cooling system, power supply and optical transmission part for the output light. The transmission part of the light source was developed to collimate the light with desired wavelength into input of fiber optic. Output powers are obtained average 99.91 mW for 450±40 nm, 111.01 mW for 530±10nm, and 78.50 mW for 632.8±10nm.

Development of excitation light source for photodynamic diagnosis

Photodynamic diagnosis (PDD) is a method to diagnose the possibility of cancer, both by the principle that if a photosensitizer is injected into an organic tissue, it is accumulated in the tissue of a malignant tumor selectively after a specific period, and by a comparison of the intensity of the fluorescence of normal tissue with abnormal tissue after investigating the excitation light of a tissue with accumulated photosensitizer. Currently, there are two methods of PDD: The first is a way to acquire incitement fluorescence by using a photosensitizer, and the second is a way to use auto-fluorescence by green fluorescence protein (GFP) and red fluorescence protein (RFP) such as NADH+ active factors within the organic body. Since the selection of the wavelength band of excitation light has an interrelation with fluorescence generation according to the selection of a photosensitizer, it plays an important role in PDD. This study aims at designing and evaluating light source devices that can stably generate light with various kinds of wavelengths in order to make possible PDD using a photosensitizer and diagnosis using auto-fluorescence. The light source was a Xenon lamp and filter wheel, composed of an optical output control through Iris and filters with several wavelength bands. It also makes the inducement of auto-fluorescence possible because it is designed to generate a wavelength band of 380-420nm, 430-480nm, 480-560nm. The transmission part of the light source was developed to enhance the efficiency of light transmission. To evaluate this light source, the characteristics of light output and wavelength band were verified. To validate the capability of this device as PDD, the detection of auto-fluorescence using mouse models was performed.

The optimization of laser systems for photodynamic therapy of malignancies

In this paper, we optimized the PDT laser system to improve the therapy effects of malignancies. In order to optimizes, the variation of laser output and specific wavelength shift have to reduced. To improved the PDT therapy clincian require the diverse radiation mode which irradiate the tumor surface. Continuous wave mode that general application may causes tissue thermal damage not only to tumor tissue, but also to nomal tissue. Therefore, we suggested new technique for radiation method to improved PDT effects and prevented to the thermal effects for the tissue. In experimental we verified the stability of wavelength, laser output stability and proved the reduced thermal effects to the tissue using the pulse & burst radiation modes in vitro.