Dae-Hyun Kim

The first private-hospital based proton therapy center in Korea; status of the Proton Therapy Center at Samsung Medical Center

Purpose The purpose of this report is to describe the proton therapy system at Samsung Medical Center (SMC-PTS) including the proton beam generator, irradiation system, patient positioning system, patient position verification system, respiratory gating system, and operating and safety control system, and review the current status of the SMC-PTS. Materials and Methods The SMC-PTS has a cyclotron (230 MeV) and two treatment rooms: one treatment room is equipped with a multi-purpose nozzle and the other treatment room is equipped with a dedicated pencil beam scanning nozzle. The proton beam generator including the cyclotron and the energy selection system can lower the energy of protons down to 70 MeV from the maximum 230 MeV. Results The multi-purpose nozzle can deliver both wobbling proton beam and active scanning proton beam, and a multi-leaf collimator has been installed in the downstream of the nozzle. The dedicated scanning nozzle can deliver active scanning proton beam with a helium gas filled pipe minimizing unnecessary interactions with the air in the beam path. The equipment was provided by Sumitomo Heavy Industries Ltd., RayStation from RaySearch Laboratories AB is the selected treatment planning system, and data management will be handled by the MOSAIQ system from Elekta AB. Conclusion The SMC-PTS located in Seoul, Korea, is scheduled to begin treating cancer patients in 2015.

Analysis of floating debris behaviour in the Nakdong River basin of the southern Korean peninsula using satellite location tracking buoys

Most land-based debris enters the ocean via rivers during the rainy season. The Nakdong River system, the largest river entering the South Sea of Korea, discharges 3000 tons of debris per year. We deployed small tracking buoys with satellite location transmitters to monitor river-borne floating debris movement. The buoys moved for various distances depending on the change in flux in different regions. A hot spot was expected to contain a large accumulation of floating debris. The central and lower parts of the eastern downstream region were identified as important regions. The results of this study provide information related to the movement of debris that can be used when establishing a method for collection of floating debris from rivers and streams. The study contributes to efforts to decrease the amount of floating debris in oceans and the costs associated with debris removal by improving the effectiveness of preventative measures.

A Study on the Inflow and Seasonal Characteristics of Foreign Marine Debris in the Coastal Area of the West Sea

The aim of this study knows to occurrence characteristics and monthly transition of foreign marine debris by changing in the marine environment for the national marine debris monitoring areas in the west coastal area. The Jeju Island (5,112) had the highest number for foreign marine debris flowed in the coast. Many areas in the next were surveyed by Hajo Island (1,967), Imja Island (507). Plastic bottles were the most common type to 2,925 piece of the whole collection. Then, the monthly occurrence amount was concentrated in July, September. At this time, analysis results of the marine environment are as follows: The sea surface wind of southerly or southeasterly were predominated. In addition, the sea surface circulations were dominated by inflow of seawater southward along the China Coast and northward from the East China Sea.

A Study on Estimation of Submarine Groundwater Discharge Distribution Area using Landsat-7 ETM+ images around Jeju island

This study was aimed to detect Submarine Groundwater Discharge (SGD) distribution image of Sea Surface Temperature (SST) using infrared band of Landsat-7 ETM+ around Jeju island. It is used to analyze SST distribution that DN value of satellite images converted into temperature. The estimation of SGD location is that extracting range of 15∼17 °C from SST. The summer season images(July 28. 2006, Aug. 29. 2006 and Sep. 19. 2008) were used to analyze big difference between SST and temperature of SGD. The results, estimated SGD locations were occurred part of coastal area in northeastern of Jeju island.

A Study on Identification of Characteristics of Spatial Distribution for Submerged Marine Debris

The aim of this study is identifying characteristics of spatial distribution using submerged debris data on the bottom of sea ground. Marine debris is classified into floating and submerged debris. These are polluting marine environment, ecology and habitat by floating and submerged. Also it takes a lot of money when it is to process the waste flowing into the ocean. In this study, it is used data of submerged debris by side scan sonar on the bottom of sea ground in Pohang port. Submerged distribution map is made to identify spatial classified characteristics of SMD(submerged marine debris) using by position and weight per area of SMD.

A Study on Estimation of Submarine Groundwater Discharge Distribution area using IR camera and Field survey around Jeju island

This study was aimed to detect area of Submaine Groundwater Discharged(: SGD) around Jeju island using by remote sensing. Sea Surface Temperature(SST) was identified using IR camera on Unmaned Aerial Vehicle(UAV) at Gimnyeong port in study area. Then SGD location was detected by comparing range of SGD temperature. Generally, range of SGD temperature is distributed 15 to 17 like underground water. The result, SGD location was detected by SST distribution of Gimnyeong port recorded by IR camera in the southwest of study area.

Temporal and Spatial Variations of SL/SST in the Korean Peninsula by Remote Sensing

NOAA/AVHRR, Topex/Poseidon, and Jason-1 data were used to analyze sea surface temperatures and thermal fronts in the North East Asia Seas. Temporal and spatial analyses were based on data from 1993 to 2008. The amplitude and phase for the annual mode on SL and SST were investigated with harmonic analysis. The geographical distribution of amplitudes for comparison of SL and SST are slightly reverse in southwest-northeast tilted direction. The time series analysis conducted on the entire researched area presented consistent pattern. Peak of Sea Level was presented 1~2 months after the peak of the surface sea temperature was shown. This explains that Sea Level change occurs after the generation of surface sea temperature change in sea. The Sobel edge detection method delineated four fronts. Thermal fronts generally occurred over steep bathymetric slopes. Annual amplitudes and phases were bounded within these frontal areas.

MEASUREMENT OF NEUTRON AMBIENT DOSE EQUIVALENT IN PROTON RADIOTHERAPY WITH LINE-SCANNING AND WOBBLING MODE TREATMENT SYSTEM

Abstract The primary objective of this study was to measure secondary neutron dose during proton therapy using a detector that covers the entire neutron energy range produced in proton therapy. We analyzed and compared the neutron dose during proton treatment with passive scattering and line scanning. The neutron ambient dose equivalents were measured with a 190 MeV wobbling and line‐scanning proton beam. The center of a plastic water phantom (30 × 30 × 60 cm3) was placed at the isocenter. A Wide‐Energy Neutron Detection Instrument (WENDI‐2) was located 1m from the isocenter at four different angles (0°, 45°, 90° and 135°). Both wobbling and line‐scanning modes of a multipurpose and pencil beam scanning dedicated nozzles were used to obtain a spread‐out Bragg peak with 10‐cm‐width for the measurements. The ambient dose equivalent H*(10) value was normalized by the proton therapeutic dose at the isocenter. For wobbling mode and line‐scanning mode, the highest H*(10) values were 1.972 and 0.099 mSv/Gy, respectively. We successfully measured the neutron ambient dose equivalents at six positions generated by a 190 MeV proton beam using wobbling and line‐scanning mode with the WENDI‐2. These reference data could be used for neutron dose reduction methods and other analysis for advanced proton treatment in the near future.