• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.11a
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• pp.47-55
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• 2005

A design of a dismantling mock-up system have been established based on the result that analyzed a characteristic of modules which need to design a virtual dismantling facility. A unit program composed of a various module such as a decommissioning database system. 3D dosimetric mapping that represents a distribution of a radionuclide contamination, a evaluation module for a dismantling schedule and cost A research of software architecture was carried out in order to Integrate these components that have been independently operated. The result was established an architecture that consis of a visualization module which could be visualized D&D activities and a simulation module which tan he evaluated a dismantling schedule and decommissioning cost.

• Progress in Medical Physics
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• v.31 no.4
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• pp.153-162
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• 2020

Purpose: We aim to evaluate the accuracy and effectiveness of an automatically converted radiation therapy plan between Radixact machines by comparing the original plan with the transferred plan. Methods: The study involved a total of 20 patients for each randomly selected treatment site who received radiation treatment with Radixact. We set up the cheese phantom (Gammex RMI, Middleton, WI, USA) with an Exradin A1SL ion chamber (Standard Imaging, Madison, WI, USA) and GAFCHROMIC EBT3 film (International Specialty Products, Wayne, NJ, USA) inserted. We used three methods to evaluate an automatically converted radiation therapy plan using the features of the Plan transfer. First, we evaluated and compared Planning target volume (PTV) coverage (homogeneity index, HI; conformity index, CI) and organs at risk (OAR) dose statistics. Second, we compared the absolute dose using an ion chamber. Lastly, we analyzed gamma passing rates using film. Results: Our results showed that the difference in PTV coverage was 1.72% in HI and 0.17% in CI, and majority of the difference in OAR was within 1% across all sites. The difference (%) in absolute dose values was averaging 0.74%. In addition, the gamma passing rate was 99.64% for 3%/3 mm and 97.08% for 2%/2 mm. Conclusions: The Plan transfer function can be reliably used in appropriate situations.

• Nuclear Engineering and Technology
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• v.55 no.2
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• pp.669-673
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• 2023

Introduction: The crucial step in preclinical process of radiopharmaceutical production is internal dosimetry evaluation by different ways to realize radiobiological dose-response relationships and to extract the results for clinical use. Till now several bone-seeking radiopharmaceuticals have been developed for bone metastasis. Interesting features of bisphosphonates attracted attentions to them in the field of radiopharmaceutical therapy and studies on new generation of them have been doing too. Materials and methods: In this study, we used ZNA as representative of the third generation. The radiopharmaceutical ¹⁸⁸Re-ZNA was produced and its radiochemical purity was investigated. Then, the biological distribution of the produced radiopharmaceutical at 1, 2, 4 and 24 h after injection on different organs of mice were investigated. Finally, the absorbed dose of organs in the human body was assessed using the RADAR method. Results: The results show 96% radiochemical purity of the ¹⁸⁸Re-ZNA radiopharmaceutical. The amount of %ID/g in bone is 1.131% after 1 h and in 24 h it has a significant amount compared to other organs, that is 0.516%. Also dosimetric results show that the highest absorption dose is related to bone and the amount of this dose is 0.050 mGy/MBq. Conclusion: Considering the possibility of producing the ¹⁸⁸Re-ZNA radiopharmaceutical, as well as the proper distribution of this radiopharmaceutical in target and non-target organs and increasing the absorbed dose in bone, it can be concluded that this radiopharmaceutical can be useful in the "radiopharmaceutical therapy" in metastases.

• Journal of radiological science and technology
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• v.41 no.3
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• pp.201-207
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• 2018

The purpose of this study is to evaluate the performance of a "stealth chamber" as a novel reference chamber for measuring percentage depth dose (PDD) and profile of 6, 8 and 10 MV photon energies. The PDD curves and dose profiles with fields ranging from $3{\times}3$ to $25{\times}25cm^2$ were acquired from measurements by using the stealth chamber and CC 13 chamber as reference chamber. All measurements were performed with Varian VitalBeam linear accelerator. In order to assess the performance of stealth chamber, PDD curves and profiles measured with stealth chamber were compared with measurement data using CC13 chamber. For PPDs measured with both chambers, the dosimetric parameters such as $d_{max}$ (depth of maximum dose), $D_{50}$ (PDD at 50 mm depth), and $D_{100}$ (PDD at 100 mm depth) were analyzed. Moreover, root mean square error (RMSE) values for profiles at $d_{max}$ and 100 mm depth were evaluated. The measured PDDs and profiles between the stealth chamber and CC13 chamber as reference detector had almost comparable. For PDDs, the evaluated dosimetric parameters were observed small difference (<1%) for all energies and field sizes, except for $d_{max}$ less than 2 mm. In addition, the difference of RMSEs for profiles at $d_{max}$ and 100 mm depth was similar for both chambers. This study confirmed that the use of stealth chamber for measuring commission beam data is a feasible as reference chamber for fields ranging from $3{\times}3$ to $20{\times}20cm^2$. Furthermore, it has an advantage with respect to measurement of the small fields (less than $3{\times}3cm^2$ field) although not performed in this study.

• Progress in Medical Physics
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• v.28 no.1
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• pp.16-21
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• 2017

This study assessed the feasibility of a dual-channel (DC) compound method for film dosimetry. The red channel (RC) is usually used to ensure dosimetric quality using a conventional fraction dose because the RC is more accurate at low doses within 3 Gy than is the green channel (GC). However, the RC is prone to rapid degradation of sensitivity at high doses, while degradation of the GC is slow. In this study, the DC compound method combining the RC and GC was explored as a means of providing accurate film dosimetry for high doses. The DC compound method was evaluated at various dose distributions using EBT3 film inserted in a solid-water phantom. Measurements with $10{\times}20cm^2$ radiation field and $60^{\circ}$ dynamic-wedge were done. Dose distributions acquired using the RC and GC were analyzed with root-mean-squares-error (RMSE) and gamma analyses. The DC compound method was used based on the RC after correcting the GC for high doses in the gamma analysis. The RC and GC produced comparatively more accurate RMSE values for low and high doses, respectively. Gamma passing rates with an acceptance criterion of 3%/3 mm revealed that the RC provided rapid reduction in the high dose region, while the GC displayed a gradual decrease. In the whole dose range, the DC compound method had the highest agreement (93%) compared with single channel method using either the RC (80%) or GC (85%). The findings indicate that the use of DC compound method is more appropriate in dosimetric quality assurance for radiotherapy using high doses.

• Radiation Oncology Journal
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• v.36 no.3
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• pp.241-247
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• 2018

Purpose: A hybrid-dynamic conformal arc therapy (HDCAT) technique consisting of a single half-rotated dynamic conformal arc beam and static field-in-field beams in two directions was designed and evaluated in terms of dosimetric benefits for radiotherapy of lung cancer. Materials and Methods: This planning study was performed in 20 lung cancer cases treated with the VERO system (BrainLAB AG, Feldkirchen, Germany). Dosimetric parameters of HDCAT plans were compared with those of three-dimensional conformal radiotherapy (3D-CRT) plans in terms of target volume coverage, dose conformity, and sparing of organs at risk. Results: HDCAT showed better dose conformity compared with 3D-CRT (conformity index: 0.74 ± 0.06 vs. 0.62 ± 0.06, p < 0.001). HDCAT significantly reduced the lung volume receiving more than 20 Gy (V₂₀: 21.4% ± 8.2% vs. 24.5% ± 8.8%, p < 0.001; V₃₀: 14.2% ± 6.1% vs. 15.1% ± 6.4%, p = 0.02; V₄₀: 8.8% ± 3.9% vs. 10.3% ± 4.5%, p < 0.001; and V₅₀: 5.7% ± 2.7% vs. 7.1% ± 3.2%, p < 0.001), V₄₀ and V₅₀ of the heart (V₄₀: 5.2 ± 3.9 Gy vs. 7.6 ± 5.5 Gy, p < 0.001; V₅₀: 1.8 ± 1.6 Gy vs. 3.1 ± 2.8 Gy, p = 0.001), and the maximum spinal cord dose (34.8 ± 9.4 Gy vs. 42.5 ± 7.8 Gy, p < 0.001) compared with 3D-CRT. Conclusions: HDCAT could achieve highly conformal target coverage and reduce the doses to critical organs such as the lung, heart, and spinal cord compared to 3D-CRT for the treatment of lung cancer patients.

• Progress in Medical Physics
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• v.28 no.4
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• pp.181-189
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• 2017

The conventional delivery quality assurance (DQA) process for RapidArc (Varian Medical Systems, Palo Alto, USA), has the limitation that it measures and analyzes the dose in a phantom material and cannot analyze the dosimetric changes under the motional organ condition. In this study, a DQA method was designed to overcome the limitations of the conventional DQA process for internal target volume (ITV) based RapidArc. The dynamic DQA measurement device was designed with a moving phantom that can simulate variable target motions. The dose distribution in the real volume of the target and organ-at-risk (OAR)s were reconstructed using 3DVH with the ArcCHECK (SunNuclear, Melbourne, USA) measurement data under the dynamic condition. A total of 10 ITV-based RapidArc plans for liver-cancer patients were analyzed with the designed dynamic DQA process. The average pass rate of gamma evaluation was $81.55{\pm}9.48%$ when the DQA dose was measured in the respiratory moving condition of the patient. Appropriate method was applied to correct the effect of moving phantom structures in the dose calculation, and DVH data of the real volume of target and OARs were created with the recalculated dose by the 3DVH program. We confirmed the valid dose coverage of a real target volume in the ITV-based RapidArc. The variable difference of the DVH of the OARs showed that dose variation can occur differently according to the location, shape, size and motion range of the target. The DQA process devised in this study can effectively evaluate the DVH of the real volume of the target and OARs in a respiratory moving condition in addition to the simple verification of the accuracy of the treatment machine. This can be helpful to predict the prognosis of treatment by the accurate dose analysis in the real target and OARs.

• Progress in Medical Physics
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• v.20 no.4
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• pp.308-316
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• 2009

To achieve the accurate evaluation of given absorbed dose from output dose of linear accelerator photon beam through investigate the characteristics of LiF:Mg,Cu,P TLD powder. This experimental TL phosphor is performed with a commercial LiF:Mg,Cu,P powder (Supplied by PTW) and TL reader (LTM, France). The TLD was exposed to 6 MV X rays of linear accelerator photon beam with range 15 to 800 cGy in blind dose at two hospitals. The dose evaluation of TLD was through the experimental algorithms which were dose dependency, dose rate dependency, fading and powder weight dependency. The glow curve has shown the three peaks which are 110, 183 and 232 degrees of heating temperature and the main dosimetric peak showed highest TL response at 232 high temperature. In this experiments, the LiF:Mg,Cu,P phosphor has shown the 2.5 eV of electron trap energy with a second order. This experiments guided the dose evaluation accuracy is within 1% +2.58% of discrepancy. The TLD powder of LiF:Mg,Cu,P was analyzed to dosimetric characterists of electron captured energy and order by glow shape, and dose-TL response curve guided the accuracy within 1.0+2.58% of output dose discrepancy.

• The Journal of Korean Society for Radiation Therapy
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• v.30 no.1_2
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• pp.153-160
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• 2018

Purpose : We retrospectively analyzed doses of each radiation therapy technique used in the treatment for left breast cancer patients after partial mastectomy through dose results for normalorgans and tumor volume to use this as a clinical reference for radiation therapy of domestic left breast cancer patients. Materials and Methods : 40 patients who underwent partial mastectomy on left breast cancer were classified in 3 treatment methods. The treatment plan was evaluated by HI(homogeneity index), $D_{95%}$, and CI(conformity index), and the $V_{hot}$ for gross tumor volume and clinical target volume of each treatment method. In Cyberknife treatment, tumor volume was the same as high dose volume in the other techniques, so no consideration was given to clinical target volume. Treatment plan evaluation for normal organs were evaluated by mean dose on ipsilateral lung, heart, left anterior descending artery, opposite breast and lung, and non-target tissue. Result : Treatment with volumetric arc radiotherapy(VMAT) showed $95.84{\pm}0.75%$ of $D_{95%}$ on the clinical target volume, significantly higher than that of 3D-CRT. The $D_{95%}$ value of the total tumor volume was slightly higher than the other treatments. In Cyberknife treatment, the dose to the normal organs was significantly lower than other treatments. Overall, the maximum dose and mean dose to the heart were $26.2{\pm}6.12Gy$ and $1.88{\pm}0.2Gy$ in VMAT treatment and $20.25{\pm}9.35Gy$ and $1.04{\pm}0.19Gy$ in 3D-CRT therapy, respectively. Conclusion : In comparison on 3D-CRT and VMAT, most of the dosimetric parameters for the evaluation of the treatment plan showed similar values, so that there is no significant difference in treatment plan evaluation. It is possible to select the treatment method according to the patient's anatomical structure or possibility of breath control. Cyberknife treatment is very useful treatment for normal organs because of its accurate dose exposure to the tumor volume However, it has restrictions to treat the local area, to have relatively long treatment time and to involve invasive procedure.

• Progress in Medical Physics
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• v.7 no.2
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• pp.3-17
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• 1996

Dose compensators have been widely used in radiotherapy fields. But, few reliable verification methods have been reported. We have developed the verification method for the evaluation of the effect of dose compensator using exit beam dose profile. The exit beam dose profiles were measured with and without dose compensator. For this purpose X-Omat V films and lead screened cassettes are used and dose distibutions are compared. Phantom data are collected using CT simulator(Picker, AcQ Sim) and compensator information can be obtained from Render Plan 3-D planning System. Aluminum Compensators are generated by computer controlled milling machine. The real dose distribution in the phantom and the exit beam dose profile can be obtained simultaneously with the films in the phantom and the opposite site of the beam. Dose compensations effects for oblique beam, parallel opposing beam and inhomogeneous human phantom can be obtained using above tools. And we could simate those effects with exit beam dose profile using the method that we have developed in this study.