2019 International Vacuum Electronics Conference (IVEC), 2019
In the field of radiotherapy, as the treatment method which is combined with imaging devices beco... more In the field of radiotherapy, as the treatment method which is combined with imaging devices becomes important, there is an increasing demand for miniaturization and weight reduction of linear accelerator (LINAC), which is a core part of the radiotherapy equipment. To meet these requirements, LINAC has been developed by applying X-band RF technology and side-coupled structure. The developed LINAC is operated by an RF signal with a frequency of 9.3 GHz. The length of the RF cavity is 37 cm and the shunt impedance is 116 $M$Ω/m. The electron beam can be accelerated up to 6.3 MeV with having about beam current of 80 mA by electric field strength of 16.8 MeV/m. Based on the design parameters, the dose rate is calculated to be more than 1000 cGy/min when the source to surface distance (SSD) is 80 cm.
Recently, LINAC-based radiotherapy equipment are being developed by combining with imaging device... more Recently, LINAC-based radiotherapy equipment are being developed by combining with imaging devices such as CT or MRI, so that it is possible to precisely focus high dose radiation on tumor tissues while minimizing the normal tissue damage. In order to place the diagnostic and treatment devices simultaneously in a confined space, constraints related to interference and volume between the subsystems must be considered. To meet these requirements, the size and weight of the LINAC system need to be reduced, which can be achieved by applying X-band technology. For the purpose of use in IMRT based on image guided radiotherapy, we developed a 9.3 GHz X-band medical LINAC using side-coupled structure. The LINAC is designed to have the accelerating field strength of 16.8 MV/m, and the beam current transmission efficiency of 26 % at the end of accelerating cell when the supplied RF power is at 1.7 MW. Therefore, it can accelerate the electron beam up to 6.2 MeV with having about 90 mA beam cu...
A compact X-band linear accelerator (LINAC) system equipped with a small and lightweight magnetro... more A compact X-band linear accelerator (LINAC) system equipped with a small and lightweight magnetron was constructed to develop a high-precision image-guided radiotherapy system. The developed LINAC system was installed in an O-ring gantry where cone-beam computed tomography (CBCT) was embedded. When the O-arm gantry is rotated, an x-ray beam is stably generated, which resulted from the stable transmission of radio frequency power into the X-band LINAC system. Quality assurance (QA) tests, including mechanical and dosimetry checks, were carried out to ensure safety and operation performance according to the American Association of Physicists in Medicine's TG-51, 142, an international standard protocol established by accredited institutions. In addition, delivery QA of the radiotherapy planning system was conducted to verify intensity-modulated radiotherapy techniques. Therefore, it was demonstrated that the developed X-band LINAC system mounted on the O-arm gantry proved to be val...
2019 International Vacuum Electronics Conference (IVEC), 2019
Linear accelerators (LINAC) that generate high energy X-rays have been widely used for radiothera... more Linear accelerators (LINAC) that generate high energy X-rays have been widely used for radiotherapy. With the combination of advanced imaging modalities, an image-guided radiation therapy (IGRT) has greatly improved the quality of radiotherapy by acquiring instant knowledge of changes in tumor volume, radiation dose distribution, and effective tumoricidal doses during treatment. In this study, we developed a compact 9.3 GHz X-band LINAC system and installed on the gantry for potential applications in IGRT. We confirmed X-ray generation using radio frequency transmission tests and measured the X-ray dose rates while the gantry was rotating, which demonstrates stable and reliable operation of the developed system. The field size of an X-ray beam was $\pmb{10.31}\ \mathbf{cm}\ \times \ \pmb{10.31}\ \mathbf{cm}$ at the solid water phantom (depth 0 cm) of the film, and the standard deviation of the Xray dose was 0.016 while rotating. Therefore, we describe the design and test results of ...
Australasian Physical & Engineering Sciences in Medicine, 2019
The nondestructive dosimetry achieved with electron paramagnetic resonance (EPR) dosimetry facili... more The nondestructive dosimetry achieved with electron paramagnetic resonance (EPR) dosimetry facilitates repetitive recording by the same dosimeter to increase the reliability of data. In precedent studies, solid paraffin was needed as a binder material to make the lithium formate monohydrate (LFM) EPR dosimeter stable and nonfragile; however, its use complicates dosimetry. This study proposes a newly designed pure LFM EPR dosimeter created by inserting LFM into a 3D-printed container. Dosimetric characteristics of the LFM EPR dosimeter and container, such as reproducibility, linearity, energy dependence, and angular dependence, were evaluated and verified through a radiation therapy planning system (RTPS). The LFM EPR dosimeters were irradiated using a clinical linear accelerator. The EPR spectra of the dosimeters were acquired using a Bruker EMX EPR spectrometer. Through this study, it was confirmed that there is no tendency in the EPR response of the container based on irradiation dose or radiation energy. The results show that the LFM EPR dosimeters have a highly sensitive dose response with good linearity. The energy dependence across each photon and electron energy range seems to be negligible. Based on these results, LFM powder in a 3D-printed container is a suitable option for dosimetry of radiotherapy. Furthermore, the LFM EPR dosimeter has considerable potential for in vivo dosimetry and small-field dosimetry via additional experiments, owing to its small effective volume and highly sensitive dose response compared with a conventional dosimeter.
Current advances in radiotherapy are based on the precise imaging techniques, and there is a pres... more Current advances in radiotherapy are based on the precise imaging techniques, and there is a pressing need for the development of techniques capable of visualizing cancer tissues in real time in conjunction with radiotherapy. Indeed, the image-guided radiotherapy systems in which conventional diagnostic tools such as CT and MRI are combined with the linear accelerator (LINAC)-based radiotherapy have been extensively studied. In this work, we mounted 9.3 GHz X-band LINAC system designed by KERI on the 360 degree-rotatable O-arm system, which allows efficient integration of a diagnostic tool with the radiotherapy equipment. After mounting, the X-ray profile and percentage depth dose were measured by following the quality assurance using the AAPM TG-51, 142 protocol. The beam profile symmetry was estimated to be 102.44% with ± 3% tolerance. The X-ray dose was also measured by rotating the O-arm gantry system to confirm the stable operation of the mounted X-band LINAC. As a result, the ...
2019 International Vacuum Electronics Conference (IVEC), 2019
In the field of radiotherapy, as the treatment method which is combined with imaging devices beco... more In the field of radiotherapy, as the treatment method which is combined with imaging devices becomes important, there is an increasing demand for miniaturization and weight reduction of linear accelerator (LINAC), which is a core part of the radiotherapy equipment. To meet these requirements, LINAC has been developed by applying X-band RF technology and side-coupled structure. The developed LINAC is operated by an RF signal with a frequency of 9.3 GHz. The length of the RF cavity is 37 cm and the shunt impedance is 116 $M$Ω/m. The electron beam can be accelerated up to 6.3 MeV with having about beam current of 80 mA by electric field strength of 16.8 MeV/m. Based on the design parameters, the dose rate is calculated to be more than 1000 cGy/min when the source to surface distance (SSD) is 80 cm.
Recently, LINAC-based radiotherapy equipment are being developed by combining with imaging device... more Recently, LINAC-based radiotherapy equipment are being developed by combining with imaging devices such as CT or MRI, so that it is possible to precisely focus high dose radiation on tumor tissues while minimizing the normal tissue damage. In order to place the diagnostic and treatment devices simultaneously in a confined space, constraints related to interference and volume between the subsystems must be considered. To meet these requirements, the size and weight of the LINAC system need to be reduced, which can be achieved by applying X-band technology. For the purpose of use in IMRT based on image guided radiotherapy, we developed a 9.3 GHz X-band medical LINAC using side-coupled structure. The LINAC is designed to have the accelerating field strength of 16.8 MV/m, and the beam current transmission efficiency of 26 % at the end of accelerating cell when the supplied RF power is at 1.7 MW. Therefore, it can accelerate the electron beam up to 6.2 MeV with having about 90 mA beam cu...
A compact X-band linear accelerator (LINAC) system equipped with a small and lightweight magnetro... more A compact X-band linear accelerator (LINAC) system equipped with a small and lightweight magnetron was constructed to develop a high-precision image-guided radiotherapy system. The developed LINAC system was installed in an O-ring gantry where cone-beam computed tomography (CBCT) was embedded. When the O-arm gantry is rotated, an x-ray beam is stably generated, which resulted from the stable transmission of radio frequency power into the X-band LINAC system. Quality assurance (QA) tests, including mechanical and dosimetry checks, were carried out to ensure safety and operation performance according to the American Association of Physicists in Medicine's TG-51, 142, an international standard protocol established by accredited institutions. In addition, delivery QA of the radiotherapy planning system was conducted to verify intensity-modulated radiotherapy techniques. Therefore, it was demonstrated that the developed X-band LINAC system mounted on the O-arm gantry proved to be val...
2019 International Vacuum Electronics Conference (IVEC), 2019
Linear accelerators (LINAC) that generate high energy X-rays have been widely used for radiothera... more Linear accelerators (LINAC) that generate high energy X-rays have been widely used for radiotherapy. With the combination of advanced imaging modalities, an image-guided radiation therapy (IGRT) has greatly improved the quality of radiotherapy by acquiring instant knowledge of changes in tumor volume, radiation dose distribution, and effective tumoricidal doses during treatment. In this study, we developed a compact 9.3 GHz X-band LINAC system and installed on the gantry for potential applications in IGRT. We confirmed X-ray generation using radio frequency transmission tests and measured the X-ray dose rates while the gantry was rotating, which demonstrates stable and reliable operation of the developed system. The field size of an X-ray beam was $\pmb{10.31}\ \mathbf{cm}\ \times \ \pmb{10.31}\ \mathbf{cm}$ at the solid water phantom (depth 0 cm) of the film, and the standard deviation of the Xray dose was 0.016 while rotating. Therefore, we describe the design and test results of ...
Australasian Physical & Engineering Sciences in Medicine, 2019
The nondestructive dosimetry achieved with electron paramagnetic resonance (EPR) dosimetry facili... more The nondestructive dosimetry achieved with electron paramagnetic resonance (EPR) dosimetry facilitates repetitive recording by the same dosimeter to increase the reliability of data. In precedent studies, solid paraffin was needed as a binder material to make the lithium formate monohydrate (LFM) EPR dosimeter stable and nonfragile; however, its use complicates dosimetry. This study proposes a newly designed pure LFM EPR dosimeter created by inserting LFM into a 3D-printed container. Dosimetric characteristics of the LFM EPR dosimeter and container, such as reproducibility, linearity, energy dependence, and angular dependence, were evaluated and verified through a radiation therapy planning system (RTPS). The LFM EPR dosimeters were irradiated using a clinical linear accelerator. The EPR spectra of the dosimeters were acquired using a Bruker EMX EPR spectrometer. Through this study, it was confirmed that there is no tendency in the EPR response of the container based on irradiation dose or radiation energy. The results show that the LFM EPR dosimeters have a highly sensitive dose response with good linearity. The energy dependence across each photon and electron energy range seems to be negligible. Based on these results, LFM powder in a 3D-printed container is a suitable option for dosimetry of radiotherapy. Furthermore, the LFM EPR dosimeter has considerable potential for in vivo dosimetry and small-field dosimetry via additional experiments, owing to its small effective volume and highly sensitive dose response compared with a conventional dosimeter.
Current advances in radiotherapy are based on the precise imaging techniques, and there is a pres... more Current advances in radiotherapy are based on the precise imaging techniques, and there is a pressing need for the development of techniques capable of visualizing cancer tissues in real time in conjunction with radiotherapy. Indeed, the image-guided radiotherapy systems in which conventional diagnostic tools such as CT and MRI are combined with the linear accelerator (LINAC)-based radiotherapy have been extensively studied. In this work, we mounted 9.3 GHz X-band LINAC system designed by KERI on the 360 degree-rotatable O-arm system, which allows efficient integration of a diagnostic tool with the radiotherapy equipment. After mounting, the X-ray profile and percentage depth dose were measured by following the quality assurance using the AAPM TG-51, 142 protocol. The beam profile symmetry was estimated to be 102.44% with ± 3% tolerance. The X-ray dose was also measured by rotating the O-arm gantry system to confirm the stable operation of the mounted X-band LINAC. As a result, the ...
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