basic > Research 2 페이지

Total 48

A new real-time personal dosimeter with position monitoring …

Personal dosimeters are used to measure the amount of radiation exposure in individual radiation workers. We aimed to replace existing personal dosimeters and evaluate a real-time scintillator-based dosimeter by monitoring its radiation dose and checking the location exposed to radiation in the workspace. The developed dosimeter measured the radiation dose based on a scintillating fiber (SF) bundle, and comprised a silicon photomultiplier (SiPM), ultra-wide-band (UWB)-based location detecting system, and Bluetooth system. The SF bundle was exposed to radiation-emitted light, and the photons were amplified and converted to electrical signals through the SiPM. These signals were transferred to the user through the Bluetooth system and monitored. To evaluate the feasibility of this mechanism as a dosimeter, we performed characteristic tests, such as dose linearity, dependence on dose rate, energy, exposed angle, and location coordinate mapping. Also, the dose distribution formed in circles around the iso-center was measured to confirm the feasibility of monitoring the exposure dose and location and to enable the radiation worker to move freely in a workspace. We confirmed dose linearity, independence from energy and angle, and accuracy of location monitoring in our device. The user’s locations were measured with a difference of − 6 cm and − 4.8 cm on the x- and the y-axes, respectively. The measured doses on our developed dosimeter were 62.7, 32.3, 21.0, and 15.4 mSv at distances of 50, 100, 150, and 200 cm from the iso-center. In other words, all measured doses at several points showed an error within 5% as compared to doses provided by the conventional pocket dosimeter. These results show that the developed SF-based dosimeter is advantageous in monitoring the exposure dose and location in real time, and has significant potential as a new personal dosimeter for radiation workers.

Sun Young Moon, Myonggeun Yoon

Department of Bio-Convergence Engineering, Korea University, Seoul, South Korea

Sun-Young Kim, Dongho Shin

Proton Therapy Center, National Cancer Center, Goyang, South Korea

J. Korean Phys. Soc. 78, 1133–1140 (2021).

Utility of fast non-local means (FNLM) filter for detection …

Purpose: This study was aimed to evaluate the utility based on imaging quality of the fast non-local means (FNLM) filter in diagnosing lung nodules in pediatric chest computed tomography (CT).

Methods: We retrospectively reviewed the chest CT reconstructed with both filtered back projection (FBP) and iterative reconstruction (IR) in pediatric patients with metastatic lung nodules. After applying FNLM filter with six h values (0.0001, 0.001, 0.01, 0.1, 1, and 10) to the FBP images, eight sets of images including FBP, IR, and FNLM were analyzed. The image quality of the lung nodules was evaluated objectively for coefficient of variation (COV), contrast to noise ratio (CNR), and point spread function (PSF), and subjectively for noise, sharpness, artifacts, and diagnostic acceptability.

Results: The COV was lowest in IR images and decreased according to increasing h values and highest with FBP images (P < 0.001). The CNR was highest with IR images, increased according to increasing h values and lowest with FBP images (P < 0.001). The PSF was lower only in FNLM filter with h value of 0.0001 or 0.001 than in IR images (P < 0.001). In subjective analysis, only images of FNLM filter with h value of 0.0001 or 0.001 rarely showed unacceptable quality and had comparable results with IR images. There were less artifacts in FNLM images with h value of 0.0001 compared with IR images (p < 0.001).

Conclusion: FNLM filter with h values of 0.0001 allows comparable image quality with less artifacts compared

Jina Shim, Myonggeun Yoon*

Department of Bio-Convergence Engineering, Korea University, Seoul, Republic of Korea

Department of Diagnostic Radiology, Severance Hospital, Seoul, Republic of Korea

Mi-Jung Lee*

Department of Radiology and Research Institute of Radiological Science, Severance Children’s Hospital, Yonsei University, College of Medicine, Seoul, Republic of Korea

Youngjin Lee

Department of Radiological Science, Gachon University, Incheon, Republic of Korea

Physica Medica 81 (2021) 52-89

Sensitivity of radio-photoluminescence glass dosimeters to a…

Background

This study investigated the effect of accumulated doses on radio-photoluminescence glass dosimeters (RPLGDs) from measurements involving mega-voltage photons.

Methods

Forty-five commercially available RPLGDs were irradiated to estimate their dose responses. Photon beams of 6, 10, and 15 MV were irradiated onto the RPLGDs inside a phantom, which were divided into five groups with different doses and energies. Groups 1 and 2 were irradiated at 1, 5, 10, 50, and 100 Gy in a sequential manner; Group 3 was irradiated 10 times with a dose of 10 Gy; and Groups 4 and 5 followed the same method as that of Group 3, but with doses of 50 Gy and 100 Gy, respectively. Each device was subjected to a measurement reading procedure each time irradiation.

Results

For the annealed Group 1, RPLGD exhibited a linearity response with variance within 5%. For the non-annealed Group 2, readings demonstrated hyperlinearity at 6 MV and 10 MV, and linearity at 15 MV. Following the 100 Gy irradiation, the readings for Group 2 were 118.7 ± 1.9%, 112.2 ± 2.7%, and 101.5 ± 2.3% at 6, 10, and 15 MV, respectively. For Groups 3, 4, and 5, the responsiveness of the RPLGDs gradually decreased as the number of repeated irradiations increased. The percentage readings for the 10th beam irradiation with respect to the readings for the primary beam irradiation were 84.6 ± 1.9%, 87.5 ± 2.4%, and 93.0 ± 3.0% at 6 MV, 10 MV, and 15 MV, respectively.

Conclusions

The non-annealed RPLGD response to dose was hyperlinear for the 6 MV and 10 MV photon beams but not for the 15 MV photon beam. Additionally, the annealed RPLGD exhibited a fading phenomenon when the measurement was repeated several times and demonstrated a relatively large fading effect at low energies than at high energies.

Dong Wook Kim, Han-Back Shin, Min-Joo Kim, Yu-Yun Noh, Hojae Kim, Min Cheol Han, Jihun Kim, Su Chul Han, Kyung Hwan Chang, Hojin Kim, Kwangwoo Park, Jinsung Kim

Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, Korea

Jiwon Sung, Jaeman Son

Department of Radiation Oncology, Seoul National University Hospital, Seoul, Korea

Myonggeun Yoon

Department of Bio-Convergence Engineering, Korea University, Seoul, Korea

Dongho Shin

Proton Therapy Center, National Cancer Center, Goyang, Korea

PLOS ONE | https://doi.org/10.1371/journal.pone.0234829 December 3, 2020

Tumor treating fields (TTF) treatment enhances radiation-ind…

Purpose:Tumor treating fields (TTF) therapy is a noninvasive method that uses alternating electric fields to treat various types of cancer. This study demonstrates the combined effect of TTF and radiotherapy (RT) in vitro on pancreatic cancer, which is known to be difficult to treat.

Materials and methods: In CFPAC-I and HPAF-II pancreatic cancer cell lines, the combined in vitro effect of TTF and RT was evaluated by measuring cell counts, markers of apoptosis, and clonogenic cell survival. The synergy effects were verified using the Valeriote and Carpentier equations.

Results: TTF and RT inhibited cancer cell growth more effectively than did mono therapy with TTF or RT. The combined treatment also enhanced apoptosis more than mono therapy, as shown by as says for cleaved poly (ADP-ribose) polymerase (PARP) and annexin V. In addition, on the survival curve, this treatment method has been shown to work synergistically.

Conclusion:These results suggest that combined treatment with TTF and RT may be a good alter-native treatment for patients with pancreatic cancer

Yunhui Jo

Department of Bio-convergence Engineering, Korea University, Seoul, Korea

Geon Oh, Yongha Gi, Heehun Sung, Myonggeun Yoon

Department of Bio-medical Engineering, Korea University,Seoul, Korea

Eun Bin Joo, Suk Lee

Department of Radiation Oncology, College of Medicine, Korea University, Seoul, Korea

INTERNATIONAL JOURNAL OF RADIATION BIOLOGY2020, VOL. 96, NO. 12, 1528–1533

Clinical application of a gantry-attachable plastic scintill…

Purpose: The entrance beam fluence of therapeutic proton scanning beams can be monitored using a gantry-attachable plastic scintillating plate (GAPSP). This study evaluated the clinical application of the GAPSP using amethod that measures intensity modulated proton therapy (IMPT) beams for patient treatment.

Methods: IMPT beams for the treatment of nine patients, at sites that included the spine, head and neck, pelvis, and lung, were measured using the GAPSP, composed of an EJ-212 plastic scintillator and a CMOS camera. All energy layers distinguished by the GAPSP were accumulated to determine the dose distribution of the treatment field. The evaluated fields were compared with reference dose maps verified by quality assurance.

Results: Comparison of dose distributions of evaluation treatment fields with reference dose distributions showed that the 3%/1 mm average gamma passing rate was 96.4%, independent of the treatment site, energy range and field size. When dose distributions were evaluated using the same criteria for each energy layer, the average gamma passing rate was 91.7%.

Conclusions: The GAPSP is a suitable, low-cost method for monitoring pencil beam scanning proton therapy, especially for non-spot scanning or additional collimation. The GAPSP can also estimate the treatment beam by the energy layer, a feature not common to other proton dosimetry tool.

Seonghoon Jeong

Proton Therapy Center, National Cancer Center, Goyang, Republic of Korea

Myonggeun Yoon⁎ , Jaehyeon Seo

Department of Bio-Convergence Engineering, Korea University, Seoul, Republic of Korea

Kwangzoo Chung,⁎ , Sung Hwan Ahn , Boram Lee,

Department of Radiation Oncology, Samsung Medical Center, Seoul, Republic of Korea

Physica Medica 77(2020)181-186

Feasibility Study of Beam Angle Optimization for Proton Trea…

This study describes a method that uses a genetic algorithm to select optimal beam angles in proton therapy and evaluates the effectiveness of the proposed algorithm in actual patients. In the use of the genetic algorithm to select the optimal angle, a gene represents the angle of each field and a chromosome represents the combination of beam angles. The fitness of the genetic algorithm, which represents the suitability of the chromosome to the solution, was quantified by using the dose distribution. The weighting factors of the organs used for fitness were obtained from clinical data through logistic regression, reflecting the dose characteristics of actual patients. Genetic operations, such as selection, crossover, mutation, and replacement, were used to modify the population and were repeated until an evaluation based on fitness reached the termination criterion. The proposed genetic algorithm was tested by assessing its ability to select optimal beam angles in three patients with liver cancer. The optimal results for fitness, planning target volume (PTV), normal liver, and skin in the population were compared with the clinical treatment plans, a process that took an average of 36.8 minutes. The dose-volume histograms (DVHs) and the fitness of the genetic algorithm plans did not differ significantly from the actual treatment plans. These findings indicate that the proposed genetic algorithm can automatically generate proton treatment plans with the same quality as actual clinical treatment plans.

Jaehyeon Seo, Yunhui Jo, Sunyoung Moon and Myonggeun Yoon∗

Department of Bio-convergence Engineering, Korea University, Seoul 02841, Korea

Sung Hwan Ahn, Boram Lee and Kwangzoo Chung†

Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Korea

Seonghoon Jeong

Department of Proton Therapy Center, National Cancer Center, Goyang 10408, Korea

Journal of the Korean Physical Society, Vol. 77, No. 4, August 2020, pp. 312∼316

Evaluating direct and indirect effects of low-energy electro…

Monte Carlo simulations can classify DNA damage into different types and predict the amount of energy deposited. Geant4-DNA was used to predict simple and complex DNA damage induced by irradiation of low-energy electrons at 0.1–50 keV. The number of molecules generated at different energy levels of radiation was analyzed after observing the gradual changes in the level of water radiolysis. ADNA model was used to categorize direct damage according to the location of strand breaks at the atomic level. The parameters of energy threshold (minimum amount of energy needed to break DNA strands) and 10 base pairs (maximum distance that separates two strand breaks) were set. All instances of water radiolysis including the main OH radical occurred most frequently at 1 keV followed by at 1.5 and 0.5 keV. Direct strand breaks most commonly occurred at 0.5 keV followed by at 0.3 keV. Finally, most of strand breaks occurred more frequently at 0.5 keV than at 0.3 keV. The computational measure-ment results for indirect and direct effects of irradiation depend on the type of simulation code and the DNA model used. Values used in Geant4 (physics list, chemical interaction time and energy threshold)may also influence the results.

Eunae Choi and Myong Geun Yoon

Department of Bio Convergence Engineering, Korea University, Seongbuk-gu, Republic of Korea

Kwon Su Chon

Catholic University of Daegu, Gyeongsan, Republic of Korea

RADIATION EFFECTS & DEFECTS IN SOLIDS2020, VOL. 175, NOS. 11–12, 1042–1051

Biophysical Model Including a Potentially Lethal Damage Repa…

The amount of potentially lethal damage repair (PLDR) is a significant factor in the process of modeling the survival curves of cells irradiated with fractionated carbon beams. Because the amount of PLDR generally depends on the features of the cells and the linear energy transfer (LET), the amount of PLDR of cells irradiated with fractionated carbon beams shows distinct differences from that of cells irradiated with X-rays. This study considered a new parameter dependent on the correlation between the PLDR trait (T) of the cells over a time interval (Δ) at the fractionated carbon beam irradiation. The survival curves of the cells irradiated with fractionated carbon beams n times were predicted using the ζ and the Ψ values from the delay assay. This study aims to overcome the barriers of traditional methods by developing a new survival curve model with new parameters based on an analysis of the PLDR traits of cells over time interval in fractionated carbon beam irradiation and to suggest a model that produces results significantly closer to the experimental data.

Eunae Choi and Myonggeun Yoon∗

Department of Bio-convergence Engineering, Korea University, Seoul 02841, Korea

Masao Suzuki and Naruhiro Matsufuji

National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan

Wonguyn Jung

Korea Institute of Radiological and Medical Science, Seoul 01812, Korea

Journal of the Korean Physical Society, Vol. 77, No. 2, July 2020, pp. 161∼167

Development of a Daily-Treatment Beam-Monitoring System Base…

This study describes the development of a simple method to assess inter-fractional deviations of delivered proton beams in treatment rooms. To monitor the treatment beam, we measured the field-by-field beam fluences by attaching the EBT3 film to the snout, followed by a simple constancy check based on comparisons between the reference beam fluences (acquired during the pre-treatment quality assurance process) and the test beam fluences (acquired during treatment). The feasibility of the proposed treatment beam-monitoring system was confirmed by evaluating 12 treatment fields for each of six patients (brain, liver, prostate, lung, cranial and spinal area, and head and neck). The constancy of the treatment beams was verified by using a gamma index analysis to compare three measurements per field with the reference beam fluence. On the basis of the 3%/3 mm criterion, the average gamma-index passing rates for all measurements were over 99.6%. These results suggest that the constancy of fractional proton beams delivered to patients in treatment rooms can be verified with EBT3 film-based proton-beam monitoring system that can be easily attached to the treatment nozzle and is cost effective.

Seonghoon Jeong

Proton Therapy Center, National Cancer Center, Goyang Korea

Myonggeun Yoon∗

Department of Bio-convergence Engineering, Korea University, Seoul, Korea

Kwangzoo Chung†

Department of Radiation Oncology, Samsung Medical Center, School of Medicine, Sungkyunkwan University, Seoul, Korea

Journal of the Korean Physical Society, Vol. 76, No. 8, April 2020, pp. 769∼773

Feasibility study of a plastic scintillating plate-based tre…

Purpose: The purpose of this study was to describe a plastic scintillating plate-based gantryattachable

dosimetry system for pencil beam scanning proton therapy to monitor entrance proton beam

fluence, and to evaluate the dosimetric characteristics of this system and its feasibility for clinical use.

Methods: The dosimetry system, consisting of a plastic scintillating plate and a CMOS camera, was

attached to a dedicated scanning nozzle and scintillation during proton beam irradiation was

recorded. Dose distribution was calculated from the accumulated recorded frames. The dosimetric

characteristics (energy dependency, dose linearity, dose rate dependency, and reproducibility) of the

gantry-attachable dosimetry system for use with therapeutic proton beams were measured, and the

feasibility of this system during clinical use was evaluated by determining selected quality assurance

items at our institution.

Results: The scintillating plate shortened the range of the proton beam by the water-equivalent thickness

of the plate and broadened the spatial profile of the single proton spot by 11% at 70 MeV. The

developed system functioned independently of the beam energy (<1.3%) and showed dose linearity,

and also functioned independently of the dose rate. The feasibility of the system for clinical use was

evaluated by comparing the measured quality assurance dose distribution to that of the treatment

planning system. The gamma passing rate with a criterion of 3%/3 mm was 97.58%.

Conclusions: This study evaluated the dosimetric characteristics of a plastic scintillating plate-based

dosimetry system for use with scanning proton beams. The ability to account for the interference of

the dosimetry system on the therapeutic beam enabled offline monitoring of the entrance beam fluence

of the pencil beam scanning proton therapy independent of the treatment system with high resolution

and in a cost-effective manner.

Seonghoon Jeong

Department of Bio-Convergence Engineering, Korea University, Seoul, Republic of Korea

Kwangzoo Chung, Sung Hwan Ahn, and Boram Lee

Department of Radiation Oncology, Sungkyunkwan University School of Medicine, Samsung Medical Center, Seoul, Republic of

Korea

Jaehyeon Seo and Myonggeun Yoon

Department of Bio-Convergence Engineering, Korea University, Seoul, Republic of Korea

Med. Phys. 47 (2), February 2020.

Tumor-treating fields induce autophagy by blocking the Akt2/…

Tumor-treating fields (TTFs) — a type of electromagnetic field-based therapy using low-intensity electrical fields — has

recently been characterized as a potential anticancer therapy for glioblastoma multiforme (GBM). However, the molecular

mechanisms involved remain poorly understood. Our results show that the activation of autophagy contributes to the TTFinduced anti-GBM activity in vitro or in vivo and GBM patient stem cells or primary in vivo culture systems. TTF-treatment

upregulated several autophagy-related genes (~2-fold) and induced cytomorphological changes. TTF-induced autophagy in

GBM was associated with decreased Akt2 expression, not Akt1 or Akt3, via the mTOR/p70S6K pathway. An Affymetrix

GeneChip miRNA 4.0 Array analysis revealed that TTFs altered the expression of many microRNAs (miRNAs). TTFinduced

autophagy upregulated miR-29b, which subsequently suppressed the Akt signaling pathway. A luciferase reporter assay confirmed that TTFs induced miR-29b to target Akt2, negatively affecting Akt2 expression thereby triggering autophagy. TTF-induced autophagy suppressed tumor growth in GBM mouse models subjected to TTFs as determined by positron emission tomography and computed tomography (PET-CT). GBM patient stem cells and a primary in vivo culture system with high Akt2 levels also showed TTF-induced inhibition. Taken together, our results identified autophagy as a critical cell death pathway triggered by TTFs in GBM and indicate that TTF is a potential treatment option for GBM.

Eun Ho Kim, Yunhui Jo1,2 , Sei Sai3 , Mung-Jin Park1 , Jeong-Yub Kim1, Jin Su Kim4, Yeon-Joo Lee 1,

Jae-Min Cho1, Seo-Young Kwak5, Jeong-Hwa Baek1, Youn Kyoung Jeong6, Jie-Young Song 1,

Myonggeun Yoon2, Sang-Gu Hwang1

Oncogene (2019) 38:6630–6646

Effectiveness of a Fractionated Therapy Scheme in Tumor Trea…

This study aimed to evaluate the biological effectiveness of cancer therapy with tumor treating fields using a fractionated

treatment scheme that was originally designed for radiotherapy. Discontinuous fractional tumor treating fields of an intensity of

0.9 to 1.2 V/cm and a frequency of 150 KHz were applied to U373 cancer cells and IEC6 normal cells for 3 days, with durations of 3, 6, 12, or 24 h/d. As the treatment duration of the tumor treating fields increased from 3 to 24 h/d, the relative tumor cell (U373) number (% of control) reduced in proportion to the treatment duration. Compared to a 25% cell number reduction (75% of

control) for the group of 6 h/d treatment at 1.2 V/cm, only 5% (70% of control) and 8% (67% of control) of additional reductions

were observed for the group of 12 and 24 h/d treatment, respectively. This experimental result indicates that the dependence on

treatment duration in tumor cell inhibition was weakened distinctly at treatment duration over 6 h/d. For normal cells (IEC6), the

relative cell number corresponding to the treatment time of the tumor treating fields at 1.2 V/cm of electric field strength was not

decreased much for the treatment times of 3, 6, and 12 h/d, revealing 93.3%, 90.0%, and 89.3% relative cell numbers, respectively, but it suddenly decreased to *73% for the 24 h/d treatment. Our results showed that the effects of tumor treating fields on tumor cells were higher than on normal cells for treatment duration of 3 to 12 h/d, but the difference became minimal for treatment duration of 24 h/d. The fractionated scheme, using tumor treating fields, reduced the treatment time while maintaining efficacy, suggesting that this method may be clinically applicable for cancer treatment.

Yunhui Jo, BS1,2, Jiwon Sung, PhD1, Hyesun Jeong, MS3,

Sunghoi Hong, PhD3, Youn Kyoung Jeong, PhD4, Eun Ho Kim, PhD2, and

Myonggeun Yoon, PhD1

Technology in Cancer Research & Treatment

Volume 18: 1-10 The Author(s) 2019

Quantitative study of fast non-local means-based denoising f…

In chest radiography, a solitary pulmonary nodule, which may be a precursor of lung cancer, is a frequently detected finding. However, as the image quality is deteriorated owing to the increase in the noise, lung cancer screening studies revealed that the likelihood of finding a nodule is lower than those of other modalities. This study quantitatively evaluates three widely used filters (median, Wiener, and total variation) and a newly proposed filter (fast non-local means (FNLM)), which reduce image noise. Images of a phantom with lung nodules, obtained from a patient using the 3D printing technology, were acquired at the chest anterior–posterior, lateral, and posterior– anterior positions. To evaluate their denoising performance, normalized noise power spectrum, contrast to noise ratio and coefficient of variation were used. In the quantitative evaluation

of the overall image, the proposed FNLM filter exhibited the best image performance. In the quantitative evaluation of the nodule image, the FNLM filter, which exhibits outstanding denoising performance and time efficiency, can be employed. Therefore, with the use of the FNLM filter in chest radiography, the detection probability of a nodule, which can be a precursor of lung

cancer, is increased, and the cancer can be prevented even with a lower dose.

Jina Shim, Myonggeun Yoon, Youngjin Lee

a Department of Bio-Convergence Engineering, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul, Republic of Korea

b Department of Diagnostic Radiology, Severance Hospital, 50-1, Yonsei-ro, Seodaemun-gu, Seoul, Republic of Korea

c Department of Radiological Science, Gachon University, 191, Hambakmoero, Yeonsu-gu, Incheon, Republic of Korea

Optik - International Journal for Light and Electron Optics 179(2019)

Toward a novel dosimetry system using acrylic disk radiation…

Purpose: Fabricate an acrylic disk radiation sensor (ADRS) and characterize the photoluminescence

signal generated from the optical device as basis for the development and evaluation of a new

dosimetry system for pencil beam proton therapy.

Methods: Based on the characteristics of the proposed optical dosimetry sensor, we established the

relation between the photoluminescence output and the applied dose using an ionization chamber.

Then, we obtained the relative integral depth dose profiles using the photoluminescence signal generated

by pencil beam irradiation at energies of 99.9 and 162.1 MeV, and compared the results with the

curve measured using a Bragg peak ionization chamber.

Results: The relation between the photoluminescence output and applied dose was linear. In addition,

the ADRS was dose independent for beam currents up to 6 Gy/min, and the calibration factor

for energy was close to 1. Hence, the energy dependence on the optical device can be disregarded.

The integral depth dose profiles obtained for the ADRS suitable agreed with the curve measured in

the Bragg peak ionization chamber without requiring correction.

Conclusions: These results suggest that the ADRS is suitable for dosimetry measurements in pencil

beam scanning, and it will be employed as a low-cost and versatile dosimetry sensor in upcoming

developments.

Shinhaeng Cho

Proton Therapy Center, National Cancer Center, Goyang, Korea

Nuri Lee

Department of Radiation and Oncology, National Medical Center, Seoul, South Korea

Sanghyeon Song

Department of Radiation and Oncology, Soon Chun Hyang University Hospital, Seoul, South Korea

Jaeman Son

Department of Radiation and Oncology, Seoul National University Hospital, Seoul, South Korea

Haksoo Kim, Jong Hwi Jeong, Se Byeong Lee, and Youngkyung Lim

Proton Therapy Center, National Cancer Center, Goyang, Korea

Sunyoung Moon and Myonggeun Yoon

Department of Bio-Convergence Engineering, Korea University, Seoul, Korea

Dongho Shina)

Proton Therapy Center, National Cancer Center, Goyang, Korea

Med. Phys. 45(11), November 2018

Study on the Dose Uncertainties in the Lung during Passive P…

A moving phantom is manufactured for mimicking lung model to study the dose uncertainty from CT number-stopping power conversion and dose calculation in the soft tissue, light lung tissue and bone regions during passive proton irradiation with compensator smearing value. The phantom is scanned with a CT system, and a proton beam irradiation plan is carried out with the use of a treatment planning system (Eclipse). In the case of the moving phantom, a RPM system is used for respiratory gating. The uncertainties in the dose distribution between the measured data and the planned data are investigated by a gamma analysis with 3%-3 mm acceptance criteria. To investigate smearing effect, three smearing values (0.3 cm, 0.7 cm, 1.2 cm) are used to for fixed and moving phantom system. For both fixed and moving phantom, uncertainties in the light lung tissue are severe than those in soft tissue region in which the dose uncertainties are within clinically tolerable ranges. As the smearing value increases, the uncertainty in the proton dose distribution decreases.

Seung Hoon Yoo

Division of Heavy-Ion Clinical Research, Korea Institute of Radiological and Medical Science, Seoul 01812, Korea

Jae Man Son and Myonggeun Yoon

Department of Department of Bio-Convergence Engineering, Korea University, Seoul 02841, Korea

Sung Yong Park

McLaren Proton Therapy Center, McLaren Cancer Institute, Flint, Michigan 48532, USA

Dongho Shin

Proton Therapy Center, National Cancer Center, Goyang 10408, Korea

Byung Jun Min

Department of Radiation Oncology, Kangbuk Samsung Hospital,

Sungkyunkwan University School of Medicine, Seoul 03181, Korea

Journal of the Korean Physical Society, Vol. 72, No. 11, June 2018, pp. 1369∼1378

1 2 3 4