• Journal of the Korean Society of Radiology
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• v.9 no.6
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• pp.343-348
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• 2015

The purpose of this study is a comparison of forward planning(FP) and inverse planning(IP) of a radiosurgery procedure. 10 patients of acoustic schwannoma MR image were used for treatment plan. FP-1,2 and IP were established under the same condition. FP and IP were compared by number of shot, conformity index(CI), paddic conformity index(PCI), gradiant index(GI) and treatment time. On average the treatment plan produced by IP tool provided an improved or similar CI, PCI, GI and reduced treatment time as compared to the FP (CI;FP-1:0.85, FP-2:0.86, IP:0.94, PCI;FP-1:0.79, FP-2:0.81, IP:0.78, GI;FP-1:2.94, FP-2:2.94, IP:3.01). The inverse planning system provides a clinically useful plan while reducing the planning time and treatment time.

• Proceedings of the KOSOMBE Conference
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• v.1994 no.12
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• pp.85-87
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• 1994

In this paper, we present an object-oriented stereotactic radiosurgery planning system, which accepts medical images such as CT and angiography, transforms the coordinates to a reference frame coordinate, calculates dose distributions, and finally displays isodose curves over the images. The user finds an adequate one for radiosurgeries after performing computer simulations on different treatment parameter sets. The object-oriented design concept was fully applied to the system composed of seven manager objects of different classes: a patient information manager, a user-interface manager, a coordinate transformation manager, a blackboard manager, a dose calculation manager, an isodose curve display manager, and a report manager. All the user interactions are carried out through the use of mouse buttons. The performance of the system was verified by four physicians and two medical physicists, and now is being used in two clinical sites.

• Journal of radiological science and technology
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• v.40 no.2
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• pp.303-309
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• 2017

To evaluate the usefulness of 3-dimensional brachytherapy(BT) planning technique based on CT in cervical cancer. Patients with cervical cancer underwent 2-D BT treatment planning and then CT scan with HDR intracavitary applicators in place with same positions. Dose was prescribed to Point A with 5Gy per fraction on 2-D BT planning. For 3-D BT planning, and dose was prescribed to the High risk CTV for BT (HR CTV) with 5Gy. The 3-D BT planning goal was to cover at least 90% of the HR CTV with target 5Gy isodose surface while limiting the dose to $2cm^3$ of bladder to less than 7.5 Gy, and $2cm^3$ of rectum to less than 5Gy. In one patient of 10 patients, $D_{2cm3}$ of rectal dose was over 5Gy and 6patients at $D_{2cm3}$ of bladder dose on 2-D BT planning. There was a tendency to underestimate ICRU bladder dose than ICRU rectal dose. CT based 3-D BT planning for cervical cancer will enable evaluation of dose distributions for tumor and critical organs at risk. So, rectal and bladder morbidity as well as geographic miss will be reduced in case of the bulky disease or uterine malposition.

• Radiation Oncology Journal
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• v.27 no.4
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• pp.240-248
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• 2009

Purpose: To provide a simple research tool that may be used to analyze a dose volume histogram from different radiation therapy planning systems for NTCP (Normal Tissue Complication Probability), OED (Organ Equivalent Dose) and so on. Materials and Metohds: A high-level computing language was chosen to implement Niemierko's EUD, Lyman-Kutcher-Burman model's NTCP, and OED. The requirements for treatment planning analysis were defined and the procedure, using a developed GUI based program, was described with figures. The calculated data, including volume at a dose, dose at a volume, EUD, and NTCP were evaluated by a commercial radiation therapy planning system, Pinnacle (Philips, Madison, WI, USA) for comparison. Results: The volume at a special dose and a dose absorbed in a volume on a dose volume histogram were successfully extracted using DVH data of several radiation planning systems. EUD, NTCP and OED were successfully calculated using DVH data and some required parameters in the literature. Conclusion: A simple DVH analyzer program was developed and has proven to be a useful research tool for radiation therapy.

• Progress in Medical Physics
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• v.30 no.4
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• pp.150-154
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• 2019

The objective of this study is to monitor the radiation doses delivered to a cardiac implantable electronic device (CIED) by comparing the absorbed doses calculated by a commercial treatment planning system (TPS) to those measured by an in vivo dosimeter. Accurate monitoring of the radiation absorbed by a CIED during radiotherapy is necessary to prevent damage to the device. We conducted this study on three patients, who had the CIED inserted and were to be treated with radiotherapy. Treatment plans were generated using the Eclipse system, with a progressive resolution photon optimizer algorithm and the Acuros XB dose calculation algorithm. Measurements were performed on the patients using optically stimulated luminescence detectors placed on the skin, near the CIED. The results showed that the calculated doses from the TPS were up to 5 times lower than the measured doses. Therefore, it is recommended that in vivo dosimetry be conducted during radiotherapy for CIED patients to prevent damage to the CIED.

• The Journal of Korean Society for Radiation Therapy
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• v.6 no.1
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• pp.146-153
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• 1994

A modified irradiation technique utilizing a linear accelerator for radiation surgery within the brain was performed in 41 cases of patients with anteriovenous malformation(AVM), astrocytoma, meningioma. etc. The treatment planning and dosimetry of small field for stereotactic radiosurgery with 10 MV X-ray isocentically mounted linear accelerator will be presented dose with field size, the central axis persent depth dose and the combined moving beam dose distribution. The three dimensional dose planning of stereotactic focusing irradiation on small size tumor region was perfomed with dose planning computer system(Therac 2300) and was verified with film dosimetry. The more the number of strip and the wider the angle of arc rotation, the larger were the dose delivered on tumor and the less the dose to surrounding the normal tissues. In this study, the using machine and method was as fellowing. 1) Apparatus : NELAC-1018 10MV X-ray 2) Strip No. : Select the 5-7 strips 3) Cone and field size are from $1{\times}1cm^2$ to $3.5{\times}3.5cm^2$, and special circular cone designed for the purpose of minimized the risk to normal tissue and those size are $0.7{\~}3.6cm{\phi}$.

• The Journal of the Korean dental association
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• v.54 no.2
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• pp.155-162
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• 2016

Radiographs can help in the diagnosis and treatment planning, but the exposure to ionizing radiation may elevate the risk of developing cancer in a person's lifetime. The objective of this review is to briefly summarize 1) radiation risk, especially cancer risks associated with diagnostic imaging, 2) linear, non-threshold (LNT) hypothesis, 3) the risks of radiation exposure to a fetus, and 4) the campaign of Image Gently. The individual risk of radiation-related cancer from any single medical imaging procedure is extremely small and it is not likely to be cancer risk at doses lower than 100 mGy, but patients may be harmed by avoiding diagnostic imaging due to fear of radiation hazard. Dentists need to understand the radiation doses delivered by various radiographic techniques and the acceptable exposure thresholds to effectively advise the patient and to reduce the unnecessary radiation

• The Journal of Korean Society for Radiation Therapy
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• v.28 no.1
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• pp.1-5
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• 2016

A dosimetric evaluation of volumetric modulated arc therapy, intensity modulated radiation therapy, and three-dimensional conformal radiation therapy for the lower extremity soft tissue sarcoma For the lower extremity soft tissue sarcoma, volumetric modulated arc therapy, intensity modulated radiation therapy, and three-dimensional conformal radiation therapy were evaluated to compare these three treatment planning technique. The mean doses to the planning target volume and the femur were calculated to evaluate target coverage and the risk of bone fracture during radiation therapy. Volumetric modulated arc therapy can reduce the dose to the femur without compromising target coverage and reduce the treatment time compared with intensity modulated radiation therapy.

• Radiation Oncology Journal
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• v.1 no.1
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• pp.47-53
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• 1983

CT scans obtained on 15 patients of head and neck malignant tumors were evaluated for their utility in ratiotherapy treatment planning. To evaluate the advantage of incorporating CT scans in radiotherapy treatment planning of head and neck malignant tumors, the dose distributions of treatment plan with and without CT scan were compared in 15 patients. And then the dose distributions of the first and second treatment plan were compared. 1. Tumor extend and localization were clearly delineated on CT scan in 12 of 15 cases (80%), suggestive in 2 (13.3%), and not seen in only one (6.7%) which had been in the postoperative state. 2. Tumor coverage after CT scan was adequate in 14 of 15 cases (93.3%) and not in only one. In one case of inadequate tumor coverage the target volume lay inside the field but reached within 0.5cm of the field margin (marginal miss). 3. The volume of normal tissue irradiated was reduced after CT scan in 12 of 15 cases (80%), increased in 1 (6.7%) and not changed in 2 (13.3%). 4. We could maximize the local control of disease and minimize unnecessary morbidity by delineating the location and extent of tumor and normal tissue with CT for treatment plannings.

• The Journal of Korean Society for Radiation Therapy
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• v.26 no.1
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• pp.11-19
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• 2014

Purpose : To derive the most appropriate factors by considering the effects of the major factors when applied to the optimization algorithm, thereby aiding the effective designing of a ideal treatment plan. Materials and Methods : The eclipse treatment planning system(Eclipse 10.0, Varian, USA) was used in this study. The PBC (Pencil Beam Convolution) algorithm was used for dose calculation, and the DVO (Dose Volume Optimizer 10.0.28) Optimization algorithm was used for intensity modulated radiation therapy. The experimental group consists of patients receiving intensity modulated radiation therapy for the head and neck cancer and dose prescription to two planned target volume was 2.2 Gy and 2.0 Gy simultaneously. Treatment plan was done with inverse dose calculation methods utilizing 6 MV beam and 7 fields. The optimal algorithm parameter of the established plan was selected based on volume dose-priority(Constrain), dose fluence smooth value and the impact of the treatment plan was analyzed according to the variation of each factors. Volume dose-priority determines the reference conditions and the optimization process was carried out under the condition using same ratio, but different absolute values. We evaluated the surrounding normal organs of treatment volume according to the changing conditions of the absolute values of the volume dose-priority. Dose fluence smooth value was applied by simply changing the reference conditions (absolute value) and by changing the related volume dose-priority. The treatment plan was evaluated using Conformal Index, Paddick's Conformal Index, Homogeneity Index and the average dose of each organs. Results : When the volume dose-priority values were directly proportioned by changing the absolute values, the CI values were found to be different. However PCI was $1.299{\pm}0.006$ and HI was $1.095{\pm}0.004$ while D5%/D95% was $1.090{\pm}1.011$. The impact on the prescribed dose were similar. The average dose of parotid gland decreased to 67.4, 50.3, 51.2, 47.1 Gy when the absolute values of the volume dose-priority increased by 40,60,70,90. When the dose smooth strength from each treatment plan was increased, PCI value increased to $1.338{\pm}0.006$. Conclusion : The optimization algorithm was more influenced by the ratio of each condition than the absolute value of volume dose-priority. If the same ratio was maintained, similar treatment plan was established even if the absolute values were different. Volume dose-priority of the treatment volume should be more than 50% of the normal organ volume dose-priority in order to achieve a successful treatment plan. Dose fluence smooth value should increase or decrease proportional to the volume dose-priority. Volume dose-priority is not enough to satisfy the conditions when the absolute value are applied solely.