Proton beams have been used for cancer treatment for more than 28 years, and several technological advancements have been made to achieve improved clinical outcomes by delivering more accurate and conformal doses to the target cancer cells while minimizing the dose to normal tissues. The state-of-the-art intensity modulated proton therapy is now prevailing as a major treatment technique in proton facilities worldwide, but still faces many challenges in being applied to the lung. Thus, in this article, the current status of proton therapy technique is reviewed and issues regarding the relevant uncertainty in proton therapy in the lung are summarized.
Lung Neoplasms ; Lung ; Proton Therapy ; Protons ; Uncertainty

PURPOSE: The planning of High-Dose-Rate (HDR) brachytherapy treatments are becoming individualized and more dependent on the treatment planning system. Therefore, computer software has been developed to perform independent point dose calculations with the integration of an isodose distribution curve display into the patient anatomy images. MATERIALS AND METHODS: As primary input data, the program takes patients' planning data including the source dwell positions, dwell times and the doses at reference points, computed by an HDR treatment planning system (TPS). Dosimetric calculations were performed in a 10x12x10 cm3 grid space using the Interstitial Collaborative Working Group (ICWG) formalism and an anisotropy table for the HDR Iridium-192 source. The computed doses at the reference points were automatically compared with the relevant results of the TPS. The MR and simulation film images were then imported and the isodose distributions on the axial, sagittal and coronal planes intersecting the point selected by a user were superimposed on the imported images and then displayed. The accuracy of the software was tested in three benchmark plans performed by Gamma-Med 12i TPS (MDS Nordion, Germany). Nine patients' plans generated by Plato (Nucletron Corporation, The Netherlands) were verified by the developed software. RESULTS: The absolute doses computed by the developed software agreed with the commercial TPS results within an accuracy of 2.8% in the benchmark plans. The isodose distribution plots showed excellent agreements with the exception of the tip region of the source's longitudinal axis where a slight deviation was observed. In clinical plans, the secondary dose calculations had, on average, about a 3.4% deviation from the TPS plans. CONCLUSION: The accurate validation of complicate treatment plans is possible with the developed software and the quality of the HDR treatment plan can be improved with the isodose display integrated into the patient anatomy information.
Anisotropy ; Axis, Cervical Vertebra ; Brachytherapy* ; Humans

PURPOSE: To develop the dose volume histogram (DVH) management software which guides the evaluation of radiotherapy (RT) plan of a new case according to the biological consequences of the DVHs from the previously treated patients. MATERIALS AND METHODS: We determined the radiation pneumonitis (RP) as an biological response parameter in order to develop DVH management software. We retrospectively reviewed the medical records of lung cancer patients treated with curative 3-dimensional conformal radiation therapy (3D-CRT). The biological event was defined as RP of the Radiation Therapy Oncology Group (RTOG) grade III or more. RESULTS: The DVH management software consisted of three parts (pre-existing DVH database, graphical tool, and Pinnacle3 script). The pre-existing DVH data were retrieved from 128 patients. RP events were tagged to the specific DVH data through retrospective review of patients' medical records. The graphical tool was developed to present the complication histogram derived from the pre-existing database (DVH and RP) and was implemented into the radiation treatment planning (RTP) system, Pinnacle3 v8.0 (Phillips Healthcare). The software was designed for the pre-existing database to be updated easily by tagging the specific DVH data with the new incidence of RP events at the time of patients' follow-up. CONCLUSION: We developed the DVH management software as an effective tool to incorporate the phenomenological consequences derived from the pre-existing database in the evaluation of a new RT plan. It can be used not only for lung cancer patients but also for the other disease site with different toxicity parameters.
Humans ; Incidence ; Lung Neoplasms ; Medical Records ; Radiation Pneumonitis ; Retrospective Studies

The funding acknowledgment in this article was partially omitted as published.

Purpose: Modern radiotherapy delivers radiation doses to targets within a few minutes using intricate multiple-beam segments determined with multi-leaf collimators (MLC). Therefore, we propose a scintillator-based dosimetry system capable of assessing the dosimetric and mechanical performance of intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) in real time. Methods: The dosimeter was equipped with a scintillator plate and two digital cameras. The dose distribution was generated by applying deep learning-based signal processing to correct the intrinsic characteristics of the camera sensor and a tomographic image reconstruction technique to rectify the geometric distortion of the recorded video. Dosimetric evaluations were performed using a gamma analysis against a two-dimensional array and radiochromic film measurements for 20 clinical cases. The average difference in the MLC position measurements and machine log files was tested for the applicability of the mechanical quality assurance (QA) of MLCs. Results: The agreement of the dose distribution in the IMRT and VMAT plans was clinically acceptable between the proposed system and conventional dosimeters. The average differences in the MLC positions for the IMRT/VMAT plans were 1.7010/2.8107 mm and 1.4722/2.7713 mm in banks A and B, respectively. Conclusions In this study, we developed an instantaneously interpretable real-time dosimeter for QA in a medical linear accelerator using a scintillator plate and digital cameras. The feasibility of the proposed system was investigated using dosimetric and mechanical evaluations in the IMRT and VMAT plans. The developed system has clinically acceptable accuracy in both the dosimetric and mechanical QAs of the IMRT and VMAT plans.

Purpose: Modern radiotherapy delivers radiation doses to targets within a few minutes using intricate multiple-beam segments determined with multi-leaf collimators (MLC). Therefore, we propose a scintillator-based dosimetry system capable of assessing the dosimetric and mechanical performance of intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) in real time. Methods: The dosimeter was equipped with a scintillator plate and two digital cameras. The dose distribution was generated by applying deep learning-based signal processing to correct the intrinsic characteristics of the camera sensor and a tomographic image reconstruction technique to rectify the geometric distortion of the recorded video. Dosimetric evaluations were performed using a gamma analysis against a two-dimensional array and radiochromic film measurements for 20 clinical cases. The average difference in the MLC position measurements and machine log files was tested for the applicability of the mechanical quality assurance (QA) of MLCs. Results: The agreement of the dose distribution in the IMRT and VMAT plans was clinically acceptable between the proposed system and conventional dosimeters. The average differences in the MLC positions for the IMRT/VMAT plans were 1.7010/2.8107 mm and 1.4722/2.7713 mm in banks A and B, respectively. Conclusions In this study, we developed an instantaneously interpretable real-time dosimeter for QA in a medical linear accelerator using a scintillator plate and digital cameras. The feasibility of the proposed system was investigated using dosimetric and mechanical evaluations in the IMRT and VMAT plans. The developed system has clinically acceptable accuracy in both the dosimetric and mechanical QAs of the IMRT and VMAT plans.

Purpose: Modern radiotherapy delivers radiation doses to targets within a few minutes using intricate multiple-beam segments determined with multi-leaf collimators (MLC). Therefore, we propose a scintillator-based dosimetry system capable of assessing the dosimetric and mechanical performance of intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) in real time. Methods: The dosimeter was equipped with a scintillator plate and two digital cameras. The dose distribution was generated by applying deep learning-based signal processing to correct the intrinsic characteristics of the camera sensor and a tomographic image reconstruction technique to rectify the geometric distortion of the recorded video. Dosimetric evaluations were performed using a gamma analysis against a two-dimensional array and radiochromic film measurements for 20 clinical cases. The average difference in the MLC position measurements and machine log files was tested for the applicability of the mechanical quality assurance (QA) of MLCs. Results: The agreement of the dose distribution in the IMRT and VMAT plans was clinically acceptable between the proposed system and conventional dosimeters. The average differences in the MLC positions for the IMRT/VMAT plans were 1.7010/2.8107 mm and 1.4722/2.7713 mm in banks A and B, respectively. Conclusions In this study, we developed an instantaneously interpretable real-time dosimeter for QA in a medical linear accelerator using a scintillator plate and digital cameras. The feasibility of the proposed system was investigated using dosimetric and mechanical evaluations in the IMRT and VMAT plans. The developed system has clinically acceptable accuracy in both the dosimetric and mechanical QAs of the IMRT and VMAT plans.

Purpose: Modern radiotherapy delivers radiation doses to targets within a few minutes using intricate multiple-beam segments determined with multi-leaf collimators (MLC). Therefore, we propose a scintillator-based dosimetry system capable of assessing the dosimetric and mechanical performance of intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) in real time. Methods: The dosimeter was equipped with a scintillator plate and two digital cameras. The dose distribution was generated by applying deep learning-based signal processing to correct the intrinsic characteristics of the camera sensor and a tomographic image reconstruction technique to rectify the geometric distortion of the recorded video. Dosimetric evaluations were performed using a gamma analysis against a two-dimensional array and radiochromic film measurements for 20 clinical cases. The average difference in the MLC position measurements and machine log files was tested for the applicability of the mechanical quality assurance (QA) of MLCs. Results: The agreement of the dose distribution in the IMRT and VMAT plans was clinically acceptable between the proposed system and conventional dosimeters. The average differences in the MLC positions for the IMRT/VMAT plans were 1.7010/2.8107 mm and 1.4722/2.7713 mm in banks A and B, respectively. Conclusions In this study, we developed an instantaneously interpretable real-time dosimeter for QA in a medical linear accelerator using a scintillator plate and digital cameras. The feasibility of the proposed system was investigated using dosimetric and mechanical evaluations in the IMRT and VMAT plans. The developed system has clinically acceptable accuracy in both the dosimetric and mechanical QAs of the IMRT and VMAT plans.

Purpose: Modern radiotherapy delivers radiation doses to targets within a few minutes using intricate multiple-beam segments determined with multi-leaf collimators (MLC). Therefore, we propose a scintillator-based dosimetry system capable of assessing the dosimetric and mechanical performance of intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) in real time. Methods: The dosimeter was equipped with a scintillator plate and two digital cameras. The dose distribution was generated by applying deep learning-based signal processing to correct the intrinsic characteristics of the camera sensor and a tomographic image reconstruction technique to rectify the geometric distortion of the recorded video. Dosimetric evaluations were performed using a gamma analysis against a two-dimensional array and radiochromic film measurements for 20 clinical cases. The average difference in the MLC position measurements and machine log files was tested for the applicability of the mechanical quality assurance (QA) of MLCs. Results: The agreement of the dose distribution in the IMRT and VMAT plans was clinically acceptable between the proposed system and conventional dosimeters. The average differences in the MLC positions for the IMRT/VMAT plans were 1.7010/2.8107 mm and 1.4722/2.7713 mm in banks A and B, respectively. Conclusions In this study, we developed an instantaneously interpretable real-time dosimeter for QA in a medical linear accelerator using a scintillator plate and digital cameras. The feasibility of the proposed system was investigated using dosimetric and mechanical evaluations in the IMRT and VMAT plans. The developed system has clinically acceptable accuracy in both the dosimetric and mechanical QAs of the IMRT and VMAT plans.

Respiratory gated radiation therapy and stereotactic body radiation therapy require identical tumor motions during each treatment with the motion detected in treatment planning CT. Therefore, this study developed a tumor motion monitoring and analysis system during the treatments employing RPM data, gated setup OBI images and a data analysis software. A respiratory training and guiding program which improves the regularity of breathing was used to patients. The breathing signal was obtained by RPM and the recorded data in the 4D console was read after treatment. The setup OBI images obtained gated at 0% and 50% of breathing phases were used to detect the tumor motion range in crenio-caudal direction. By matching the RPM data recorded at the OBI imaging time, a factor which converts the RPM motion to the tumor motion was computed. RPM data was entered to the institute developed data analysis software and the maximum, minimum, average of the breathing motion as well as the standard deviation of motion amplitude and period was computed. The computed result is exported in an excel file. The conversion factor was applied to the analyzed data to estimate the tumor motion. The accuracy of the developed method was tested by using a moving phantom, and the efficacy was evaluated for 10 stereotactic body radiation therapy patients. For the sine wave motion of the phantom with 4 sec of period and 2 cm of peak-to-peak amplitude, the measurement was slightly larger (4.052 sec) and the amplitude was smaller (1.952 cm). For patient treatment, one patient was evaluated not to qualified to SBRT due to the usability of the breathing, and in one patient case, the treatment was changed to respiratory gated treatment due the larger motion range of the tumor than treatment planed motion. The developed method and data analysis program was useful to estimate the tumor motion during treatment.
Humans ; Respiration ; Statistics as Topic