• Progress in Medical Physics
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• v.34 no.1
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• pp.1-9
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• 2023

Purpose: Although ionization chambers are widely used to measure beam commissioning data, point-by-point measurements of all the profiles with various field size and depths are time-consuming tasks. As an alternative, we investigated the feasibility of a linear diode array for commissioning a treatment planning system. Methods: The beam data of a Varian TrueBeam^® radiotherapy system at 6 and 10 MV with/without a flattening filter were measured for commissioning of an Eclipse Analytical Anisotropic Algorithm (AAA) ver.15.6. All of the necessary beam data were measured using an IBA CC13 ionization chamber and validated against Varian "Golden Beam" data. After validation, the measured CC13 profiles were used for commissioning the Eclipse AAA (AAA_CC13). In addition, an IBA LDA-99SC linear diode array detector was used to measure all of the beam profiles and for commissioning a separate model (AAA_LDA99). Finally, the AAA_CC13 and AAA_LDA99 dose calculations for each of the 10 clinical plans were compared. Results: The agreement of the CC13 profiles with the Varian Golden Beam data was confirmed within 1% except in the penumbral region, where ≤2% of a discrepancy related to machine-specific jaw calibration was observed. Since the volume was larger for the CC13 chamber than for the LDA-99SC chamber, the penumbra widths were larger in the CC13 profiles, resulting in ≤5% differences. However, after beam modeling, the penumbral widths agreed within 0.1 mm. Finally the AAA_LDA99 and AAA_CC13 dose distributions agreed within 1% for all voxels inside the body for the 10 clinical plans. Conclusions: In conclusion, the LDA-99SC diode array detector was found to be accurate and efficient for measuring photon beam profiles to commission treatment planning systems.

• Radiation Oncology Journal
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• v.33 no.3
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• pp.233-241
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• 2015

Purpose: To compare volumetric modulated arc therapy of RapidArc with robotic stereotactic body radiation therapy (SBRT) of CyberKnife in the planning and delivery of SBRT for hepatocellular carcinoma (HCC) treatment by analyzing dosimetric parameters. Materials and Methods: Two radiation treatment plans were generated for 29 HCC patients, one using Eclipse for the RapidArc plan and the other using Multiplan for the CyberKnife plan. The prescription dose was 60 Gy in 3 fractions. The dosimetric parameters of planning target volume (PTV) coverage and normal tissue sparing in the RapidArc and the CyberKnife plans were analyzed. Results: The conformity index was $1.05{\pm}0.02$ for the CyberKnife plan, and $1.13{\pm}0.10$ for the RapidArc plan. The homogeneity index was $1.23{\pm}0.01$ for the CyberKnife plan, and $1.10{\pm}0.03$ for the RapidArc plan. For the normal liver, there were significant differences between the two plans in the low-dose regions of $V_1$ and $V_3$. The normalized volumes of $V_{60}$ for the normal liver in the RapidArc plan were drastically increased when the mean dose of the PTVs in RapidArc plan is equivalent to the mean dose of the PTVs in the CyberKnife plan. Conclusion: CyberKnife plans show greater dose conformity, especially in small-sized tumors, while RapidArc plans show good dosimetric distribution of low dose sparing in the normal liver and body.

• Progress in Medical Physics
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• v.29 no.2
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• pp.73-80
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• 2018

Accelerated partial breast irradiation (APBI) is a new treatment delivery technique that decreases overall treatment time by using higher fractional doses than conventional fractionation. Here, a quantitative analysis study of CyberKnife-based APBI was performed on 10 patients with left-sided breast cancer who had already finished conventional treatment at the Inha University Hospital. Dosimetric parameters for four kinds of treatment plans (3D-CRT, IMRT, VMAT, and CyberKnife) were analyzed and compared with constraints in the NSABP B39/RTOG 0413 protocol and a published CyberKnife-based APBI study. For the 10 patients recruited in this study, all the dosimetric parameters, including target coverage and doses to normal structures, met the NSABP B39/RTOG 0413 protocol. Compared with other treatment plans, a more conformal dose to the target and better dose sparing of critical structures were observed in CyberKnife plans. Accelerated partial breast irradiation via CyberKnife is a suitable treatment delivery technique for partial breast irradiation and offers improvements over external beam APBI techniques.

• Radiation Oncology Journal
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• v.28 no.4
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• pp.238-248
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• 2010

Purpose: To compare the dose distributions between three-dimensional (3D) and four-dimensional (4D) radiation treatment plans calculated by Ray-tracing or the Monte Carlo algorithm, and to highlight the difference of dose calculation between two algorithms for lung heterogeneity correction in lung cancers. Materials and Methods: Prospectively gated 4D CTs in seven patients were obtained with a Brilliance CT64-Channel scanner along with a respiratory bellows gating device. After 4D treatment planning with the Ray Tracing algorithm in Multiplan 3.5.1, a CyberKnife stereotactic radiotherapy planning system, 3D Ray Tracing, 3D and 4D Monte Carlo dose calculations were performed under the same beam conditions (same number, directions, monitor units of beams). The 3D plan was performed in a primary CT image setting corresponding to middle phase expiration (50%). Relative dose coverage, D95 of gross tumor volume and planning target volume, maximum doses of tumor, and the spinal cord were compared for each plan, taking into consideration the tumor location. Results: According to the Monte Carlo calculations, mean tumor volume coverage of the 4D plans was 4.4% higher than the 3D plans when tumors were located in the lower lobes of the lung, but were 4.6% lower when tumors were located in the upper lobes of the lung. Similarly, the D95 of 4D plans was 4.8% higher than 3D plans when tumors were located in the lower lobes of lung, but was 1.7% lower when tumors were located in the upper lobes of lung. This tendency was also observed at the maximum dose of the spinal cord. Lastly, a 30% reduction in the PTV volume coverage was observed for the Monte Carlo calculation compared with the Ray-tracing calculation. Conclusion: 3D and 4D robotic radiotherapy treatment plans for lung cancers were compared according to a dosimetric viewpoint for a tumor and the spinal cord. The difference of tumor dose distributions between 3D and 4D treatment plans was only significant when large tumor movement and deformation was suspected. Therefore, 4D treatment planning is only necessary for large tumor motion and deformation. However, a Monte Carlo calculation is always necessary, independent of tumor motion in the lung.

• Progress in Medical Physics
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• v.28 no.2
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• pp.39-44
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• 2017

This study aims to analyze dose distribution and treatment time of endobronchial brachytherapy (EBBT) by changing the position step size of the dwell position. A solid water phantom and an intraluminal catheter were used in the treatment plan. The treatment plans were generated for 3, 5, 7, and 10 cm treatment lengths, respectively. For each treatment length, the source position step sizes were set as 2.5, 5, and 10 mm. Three reference points were set 1 cm away from the central axis of the catheter, along the axis, for uniform dose distribution. Volumetric dose distribution was calculated to evaluate the dosimetric effect. The total radiation delivery time and total dwell time were estimated for treatment efficiency, which were increased with position step sizes. At half-life time, the differences between the position step sizes in the total radiation delivery time were 18.1, 15.4, 18.0, and 24.0 s for 3, 5, 7, and 10 cm treatment lengths, respectively. The dose distributions were more homogenous by increasing the position step sizes. The dose difference of the reference point was less than 10%. In brachytherapy, this difference can be negligible. For EBBT, the treatment time is the key factor while considering the patient status. To reduce the total treatment time, EBBT can be performed with 2.5 mm position step size.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.5
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• pp.1897-1900
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• 2015

Purpose: To evaluate acute toxicity in nasopharyngeal cancer (NPC) patients treated with intensity modulated radiotherapy (IMRT)/volumetric modulated arc therapy (VMAT) with or without cisplatin-based chemotherapy. Materials and Methods: A total of 45 newly diagnosed, histologically proven non-metastatic NPC patients treated with IMRT between May 2010 and December 2012, were evaluated retrospectively, 37 planned with Eclipse and 8 with Prowess Panther treatment planning system. The doses to the planning target volumes of primary tumor and involved lymph nodes, high risk region, and uninvolved regional nodal areas were 70 Gy, 60 Gy, and 54 Gy respectively and delivered simultaneously over 33 fractions to 39 patients. Another 6 patients irradiated with sequential boost technique. Some 84.4% of patients received chemotherapy. Acute toxicities were graded according to the Radiation Therapy Oncology Group scoring criteria and Common Terminology Criteria for Adverse Events (CTCAE) for chemotherapy side effects. Results: Median age was 43 years (14-79) and all patients were WHO type II. Grade 1 mucositis and dysphagia were observed in 17 (37.8%), and 10 (22.2%) patients, respectively. The incidence of acute grade 2 mucositis and dysphagia was 55.6% and 68.9%, respectively. The most common chemoradiotherapy related acute toxicities were nausea, leucopenia and thrombocytopenia. Grade 3 toxicity was detected in 13 (28.8%) cases. No grade 4 toxicity was occurred. Mean weight loss was 9%. None of the patients required the insertion of percutaneous endoscopic gastrostomy for nutritional support. Radiation therapy was completed without interruption in all patients. Conclusions: IMRT is a safe and effective treatment modality, and well tolerated by patients in the treatment of nasopharyngeal carcinoma. No unexpected side effects were observed.

• Progress in Medical Physics
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• v.13 no.2
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• pp.104-108
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• 2002

As intensity modulated radiation therapy compared with conventional radiation therapy, tumor target dose increased and normal tissues and critical organs dose reduced. In brain tumor, treatment planning of intensity modulated radiation therapy was practiced in 4MV, 6MV, 15MV X-ray energy. In these X-ray energy, was considered the dose distribution and dose volume histogram. As 4MV X-ray compared with 6MV and 15MV, maximum dose of right optic-nerve increased 10.1％, 8.4％. Right eye increased 5.2％, 2.7％. And left optic-nerve, left eye, optic chiasm and brainstem increased 1.7％ - 5.2％. Even though maximum dose of PTV and these critical organs show different from 1.7％ - 10.1％ according to X-ray energies, these are a piont dose. Therefore in brain tumor, treatment planning of intensity modulated radiation therapy in 9 treatment field showed no relation with energy dependency.

• The Journal of Korean Society for Radiation Therapy
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• v.32
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• pp.31-39
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• 2020

Purpose: The aims of this study were to compare the superficial dose with Optically Stimulated Luminescence Dosimeter(OSLD) measurement and Treatment Planning System(TPS) calculation for 6MV-Flattening Filter Free(FFF) energy using HalcyonTM and TrueBeamTM. Materials and methods: Phantom study was performed using the CT images of human phantom. In the treatment planning system, the Planning Target Volume(PTV) was contoured which is similar to Glottic cancer. Furthermore, Point(M), Point(R), and Point(L) were contoured at the iso-center of head and neck region and 5mm bolus was applied to the body contour. Each treatment plans using 6MV-FFF energy from HalcyonTM and TrueBeamTM with static Intensity Modulated Radiation Therapy(IMRT) and Volumetric Modulated Arc Therapy(VMAT) were established with eclipse. To reproduce the same position as the TPS, OSLDs were placed at the iso-center point and 5mm bolus was applied to compare the error rate after the dose delivery. Result: The results of the study using human phantom are as follows. In case of HalcyonTM, the mean absolute error rates of the point dose using the treatment planning system and the dose measured by OSLD were 1.7%±1.2% for VMAT and 4.0±2.8% for IMRT. Also TrueBeamTM was identified as 2.4±0.4% and 8.6±1.8% respectively for VMAT and IMRT. Conclusion: Through the results of this study, TrueBeamTM confirmed that the average error rate was 2.4 times higher for VMAT and 3.6 times higher for IMRT than HalcyonTM. Therefore, based on the results of this study, If we need a more accurate dose assessment for the superficial dose, It is expected that using HalcyonTM would be better than TrueBeamTM.

• Progress in Medical Physics
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• v.17 no.3
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• pp.144-152
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• 2006

The telemedicine using independent client-server system via networks can provide high quality normalized services to many hospitals, specifically to local/rural area hospitals. This will eventually lead to a decreased medical cost because the centralized institute can handle big computer hardware systems and complicated software systems efficiently and economically, Customized cancer radiation treatment planning for each patient Is very useful for both a patient and a doctor because it makes possible for the most effective treatment with the least possible dose to patient. Radiation planners know that too small a dose to the tumor can result in recurrence of the cancer, while too large a dose to healthy tissue can cause complications or even death. The best solution is to build an accurate planning simulation system to provide better treatment strategies based on each patient's computerized tomography (CT) image. We are developing a web-based and a network-based customized cancer radiation therapy simulation system consisting of four Important computer codes; a CT managing code for preparing the patients target data from their CT image files, a parallel Monte Carlo high-energy beam code (PMCEPT code) for calculating doses against the target generated from the patient CT image, a parallel linear programming code for optimizing the treatment plan, and scientific data visualization code for efficient pre/post evaluation of the results. The whole softwares will run on a high performance Beowulf PC cluster of about 100-200 CPUs. Efficient management of the hardware and software systems is not an easy task for a hospital. Therefore, we integrated our system into the client-sewer system via network or web and provide high quality normalized services to many hospitals. Seamless communication with doctors is maintained via messenger function of the server-client system.

• Proceedings of the Korean Nuclear Society Conference
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• 2005.10a
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• pp.816-817
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• 2005