The first private-hospital based proton therapy center in Korea

Kwangzoo Chung,Youngyih Han,Jinsung Kim,Sung Hwan Ahn,Sang Gyu Ju,Sang Hoon Jung,Yoonsun Chung,Sungkoo Cho,Kwanghyun Jo,Eun Hyuk Shin,Chae-Seon Hong,Jung Suk Shin,Seyjoon Park,Dae-Hyun Kim,Hye Young K 대한방사선종양학회 2015 Radiation Oncology Journal Vol.33 No.4

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.

A Pilot Study of the Scanning Beam Quality Assurance Using Machine Log Files in Proton Beam Therapy

Chung, Kwangzoo Korean Society of Medical Physics 2017 의학물리 Vol.28 No.3

The machine log files recorded by a scanning control unit in proton beam therapy system have been studied to be used as a quality assurance method of scanning beam deliveries. The accuracy of the data in the log files have been evaluated with a standard calibration beam scan pattern. The proton beam scan pattern has been delivered on a gafchromic film located at the isocenter plane of the proton beam treatment nozzle and found to agree within ${\pm}1.0mm$. The machine data accumulated for the scanning beam proton therapy of five different cases have been analyzed using a statistical method to estimate any systematic error in the data. The high-precision scanning beam log files in line scanning proton therapy system have been validated to be used for off-line scanning beam monitoring and thus as a patient-specific quality assurance method. The use of the machine log files for patient-specific quality assurance would simplify the quality assurance procedure with accurate scanning beam data.

Commissioning and Validation of a Dedicated Scanning Nozzle at Samsung Proton Therapy Center

Chung, Kwangzoo,Han, Younyih,Ahn, Sung Hwan,Kim, Jin Sung,Nonaka, Hideki Korean Society of Medical Physics 2016 의학물리 Vol.27 No.4

In this study, we present the commissioning and validation results of a dedicated scanning nozzle. The dedicated scanning nozzle is installed in one of the two gantry treatment rooms at Samsung Proton Therapy Center. Following a successful completion of the acceptance test, the commissioning process including the beam data measurement for treatment planning system has been conducted. Extended measurements have been conducted as a validation of the clinical performance of the nozzle and various quality assurance protocols have been prepared.

Radiochromic film based transit dosimetry for verification of dose delivery with intensity modulated radiotherapy.

Chung, Kwangzoo,Yoon, Myonggeun,Son, Jaeman,Yong Park, Sung,Lee, Kiho,Shin, Dongho,Kyung Lim, Young,Byeong Lee, Se The American Association of Physicists in Medicine 2013 Medical physics Vol.40 No.2

<P>To evaluate the transit dose based patient specific quality assurance (QA) of intensity modulated radiation therapy (IMRT) for verification of the accuracy of dose delivered to the patient.</P>

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

Chung, Kwangzoo,Han, Youngyih,Kim, Jinsung,Ahn, Sung Hwan,Ju, Sang Gyu,Jung, Sang Hoon,Chung, Yoonsun,Cho, Sungkoo,Jo, Kwanghyun,Shin, Eun Hyuk,Hong, Chae-Seon,Shin, Jung Suk,Park, Seyjoon,Kim, Dae-Hy The Korean Society for Radiation Oncology 2015 Radiation Oncology Journal Vol.33 No.4

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.

Search for practical scaling factors of Bragg peak arrangement for line-scanning proton beam therapy in RayStation

Chung Kwangzoo,Kim Nalee,Cho Won Kyung,Kim Haeyoung,Oh Dongryul,Park Won,Park Hee Chul,Lim Do Hoon 한국물리학회 2024 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.84 No.5

To enhance the efciency of treatment planning and beam delivery in line-scanning proton beam therapy, we conducted a comparative analysis of various strategies for arranging the Bragg peak within the optimization of treatment plans. In RayStation, we had the fexibility to manipulate optimization parameters, specifcally energy layer and line spacing, to control the Bragg peak’s location. To assess the impact of these parameters, we created a virtual spherical target and generated treatment plans employing both single and dual beams with diverse arrangement strategies. We then evaluated the target volume coverage using the homogeneity index. Furthermore, we selected 15 line-scanning plans. For each line-scanning plan, we generated nine comparative plans, employing distinct Bragg peak arrangement strategies. These strategies involved variations in energy layer and line spacing settings. We optimized these plans and compared their quality to the default setting. In addition, treatment planning and beam delivery efciency were estimated. Our analysis indicated that smaller energy layer and line spacing generally resulted in improved homogeneity indices. Notably, reducing line spacing proved to be more efcient than decreasing energy layer spacing, a trend that remained consistent in the line-scanning plans. For linescanning plans, adjustments in line spacing produced more efcient improvements in the conformity index and D1cc. Based on our fndings, adjusting line spacing is a more efective strategy for optimizing Bragg peak placement in RayStation. This adjustment not only enhances treatment planning but also improves beam delivery efciency by reducing the time required for energy layer switching.

Searching for optimized selection of Monte Carlo dose calculation parameters for scanned beam proton therapy in RayStation

Kim Heejung,Chung Kwangzoo,Han Youngyih,Park Won,Park Hee Chul,Lim Do Hoon,Choi Doo Ho 한국물리학회 2023 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.83 No.7

To provide a practical guide on the selection of Monte Carlo (MC) dose calculation parameters for scanned beam proton therapy in RayStation, we generated treatment plans with various combinations of two MC dose calculation parameters in the optimization and compared the elapsed time and dosimetric properties of those plans. We selected 23 clinical cases treated with scanned beam proton therapy. For each clinically approved treatment plan, we generated 26 exploring plans (1 plan with clinical pencil beam dose algorithm and 25 plans with MC dose algorithm with varying dose calculation parameters). We recorded the elapsed time for individual plans in the dose calculation using an automated RayStation script. To evaluate the dosimetric quality of the exploring plans, the conformity and homogeneity indices of each plan were calculated and dose–volume histograms for the target volume and organs-at-risk were assessed. We found the combination of 12,000 ions/ spot in the optimization and 0.5% uncertainty in the fnal dose calculation would provide a dosimetrically competent plan with a reasonable amount of dose calculation time. We would suggest using 8000 ions/spot in the optimization and 1.0% uncertainty in the fnal dose calculation as a starting point in the treatment planning of scanned beam proton therapy. The practical recommendations resulting from this study, related to MC dose calculations, have the potential to enhance treatment planning strategies for scanned beam proton therapy and to make the iterative process of treatment planning more efcient.

Risk of second cancer from scattered radiation of intensity-modulated radiotherapies with lung cancer

Kim, Dong Wook,Chung, Weon Kuu,Shin, Dongoh,Hong, Seongeon,Park, Sung Ho,Park, Sung-Yong,Chung, Kwangzoo,Lim, Young Kyung,Shin, Dongho,Lee, Se Byeong,Lee, Hyun-ho,Yoon, Myonggeun BioMed Central 2013 Radiation oncology Vol.8 No.-

<P><B>Purpose</B></P><P>To compare the risk of secondary cancer from scattered and leakage doses following intensity-modulated radiotherapy (IMRT), volumetric arc therapy (VMAT) and tomotherapy (TOMO) in patients with lung cancer.</P><P><B>Methods</B></P><P>IMRT, VMAT and TOMO were planned for five lung cancer patients. Organ equivalent doses (OEDs) are estimated from the measured corresponding secondary doses during irradiation at various points 20 to 80 cm from the iso-center by using radio-photoluminescence glass dosimeter (RPLGD).</P><P><B>Results</B></P><P>The secondary dose per Gy from IMRT, VMAT and TOMO for lung cancer, measured 20 to 80 cm from the iso-center, are 0.02~2.03, 0.03~1.35 and 0.04~0.46 cGy, respectively. The mean values of relative OED of secondary dose of VMAT and TOMO, which is normalized by IMRT, ranged between 88.63% and 41.59% revealing 88.63% and 41.59% for thyroid, 82.33% and 41.85% for pancreas, 77.97% and 49.41% for bowel, 73.42% and 72.55% for rectum, 74.16% and 81.51% for prostate. The secondary dose and OED from TOMO became similar to those from IMRT and VMAT as the distance from the field edge increased.</P><P><B>Conclusions</B></P><P>OED based estimation suggests that the secondary cancer risk from TOMO is less than or comparable to the risks from conventional IMRT and VMAT.</P>

Risk of secondary cancers from scattered radiation during intensity-modulated radiotherapies for hepatocellular carcinoma

Kim, Dong Wook,Chung, Kwangzoo,Chung, Weon Kuu,Bae, Sun Hyun,Shin, Dong Oh,Hong, Seongeon,Park, Sung Ho,Park, Sung-Yong,Hong, Chae-Seon,Lim, Young Kyung,Shin, Dongho,Lee, Se Byeong,Lee, Hyun-ho,Sung, BioMed Central 2014 Radiation oncology Vol.9 No.-

<P><B>Purpose</B></P><P>To evaluate and compare the risks of secondary cancers from therapeutic doses received by patients with hepatocellular carcinoma (HCC) during intensity-modulated radiotherapy (IMRT), volumetric arc therapy (VMAT), and tomotherapy (TOMO).</P><P><B>Methods</B></P><P>Treatments for five patients with hepatocellular carcinoma (HCC) were planned using IMRT, VMAT, and TOMO. Based on the Biological Effects of Ionizing Radiation VII method, the excess relative risk (ERR), excess absolute risk (EAR), and lifetime attributable risk (LAR) were evaluated from therapeutic doses, which were measured using radiophotoluminescence glass dosimeters (RPLGDs) for each organ inside a humanoid phantom.</P><P><B>Results</B></P><P>The average organ equivalent doses (OEDs) of 5 patients were measured as 0.23, 1.18, 0.91, 0.95, 0.97, 0.24, and 0.20 Gy for the thyroid, lung, stomach, liver, small intestine, prostate (or ovary), and rectum, respectively. From the OED measurements, LAR incidence were calculated as 83, 46, 22, 30, 2 and 6 per 10<SUP>4</SUP> person for the lung, stomach, normal liver, small intestine, prostate (or ovary), and rectum.</P><P><B>Conclusions</B></P><P>We estimated the secondary cancer risks at various organs for patients with HCC who received different treatment modalities. We found that HCC treatment is associated with a high secondary cancer risk in the lung and stomach.</P>

Secondary Neutron Dose Measurement for Proton Line Scanning Therapy

Lee, Chaeyeong,Lee, Sangmin,Chung, Kwangzoo,Han, Youngyih,Chung, Yong Hyun,Kim, Jin Sung Korean Society of Medical Physics 2016 의학물리 Vol.27 No.3

Proton therapy is increasingly being actively used in the treatment of cancer. In contrast to photons, protons have the potential advantage of delivering higher doses to the cancerous tissue and lower doses to the surrounding normal tissue. However, a range shifter is needed to degrade the beam energy in order to apply the pencil beam scanning technique to tumors located close to the minimum range. The secondary neutrons are produced in the beam path including within the patient's body as a result of nuclear interactions. Therefore, unintended side effects may possibly occur. The research related to the secondary neutrons generated during proton therapy has been presented in a variety of studies worldwide, since 2007. In this study, we measured the magnitude of the secondary neutron dose depending on the location of the detector and the use of a range shifter at the beam nozzle of the proton scanning mode, which was recently installed. In addition, the production of secondary neutrons was measured and estimated as a function of the distance between the isocenter and detector. The neutron dose was measured using WENDI-II (Wide Energy Neutron Detection Instruments) and a Plastic Water phantom; a Zebra dosimeter and 4-cm-thick range shifter were also employed as a phantom. In conclusion, we need to consider the secondary neutron dose at proton scanning facilities to employ the range shifter reasonably and effectively.