• Progress in Medical Physics
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• v.12 no.2
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• pp.171-175
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• 2001

We analyze the relation of dose volume histogram, conformity index and homogeneity index based on RTOG9005 for treatment planning result between framed based stereotactic radiosurgery(SRS) system and frameless SRS/T system to verify the difference of two systems in the intracranial target. There is same treatment planning result by two treatment planning systems.

• Progress in Medical Physics
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• v.21 no.3
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• pp.298-303
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• 2010

The aim of this study was to compare the dose distribution of intensity modulated radiation therapy (IMRT) with 3 dimensional conformal radiation therapy (3DCRT) in prostate cancer. The IMRT plan and the 3DCRT plan used the 9 fields technique, respectively. In IMRT, tumor dose was a total dose of 66 Gy at 2.0 Gy per day, 5 days a week for 5 weeks. All cases were following the dose volume histogram (DVH) constraints. The maximum and minimum tumor dose constraints were 6,700 cGy and 6,500 cGy, respectively. The rectum dose constraints were <35% over 50 Gy. The bladder dose constraints were <35% over 40 Gy. The femur head dose constraints were <15% over 20 Gy. Tumor dose in the 3DCRT were 66 Gy. In IMRT, the maximum dose of PTV was 104.4% and minimum dose was 89.5% for given dose. In 3DCRT, the maximum dose of PTV was 105.3% and minimum dose was 85.5% for given dose. The rectum dose was 34.0% over 50 Gy in IMRT compared with 63.3% in 3DCRT. The bladder dose was 30.1% over 40 Gy in IMRT compared with 30.6% in 3DCRT. The right femur head dose was 9.5% over 20 Gy in IMRT compared with 17.5% in 3DCRT. The left femur head dose was 10.6% over 20 Gy in IMRT compared with 18.3% in 3 DCRT. The dose of critical organs (rectum, bladder, and femur head) in IMRT showed to reduce than dose of 3DCRT. The rectum dose over 50 Gy in IMRT was reduced 29.3% than 3DCRT. The bladder dose over 40 Gy in IMRT was similar to 3DCRT. The femur head dose over 20 Gy in IMRT was reduced about 7~8% than 3DCRT.

• Journal of the Korean Society of Radiology
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• v.10 no.4
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• pp.233-239
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• 2016

Comparison of the dose aspect that radiation therapy treatments using IMRT, tomotherapy, mArc (modulated arc therapy). The experimental subject is non-small cell lung cancer patient. The prescription dose is 58.0 Gy to the volume of PTV(planning target volume). and spinal cord, esophagus, and liver organ is the normal organ(OAR, organ at risk). Average PTV value is 57.60 Gy in mArc and 61.04 Gy in tomotherapy and 58.95 Gy in IMRT. The average dose of the Esophagus is 2.84 Gy in m-Arc, 5.14 Gy in tomotherapy, 1.84 Gy in IMRT. The average dose of the Liver is 19.44 Gy in m-Arc, 12.22 Gy in tomotherapy, 21.97 Gy in IMRT. The average dose of the Spinal cord is 5.72 Gy in m-Arc, 7.08 Gy in tomotherapy, 6.15 Gy in IMRT. Results of this study is no significant difference between mArc and tomotherapy and Linac based IMRT in dose study and also, mArc's dose coverage and dose volume histogram is better than IMRT and tomotherapy. but, This study is limited to a disease of cancer. in addition, fewer number of groups. The wide range the more research can be developed patient-specific treatment techniques and be applied to the patients

• Journal of the Korean Society of Radiology
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• v.14 no.2
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• pp.105-109
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• 2020

Intensity-modulated radiotherapy(IMRT) has disadvantages such as increasing the low doses of irradiation to normal tissues and accumulated dose for the whole volume by leakage and transmission of the Multi Leaf Collimator (MLC). The accumulated dose and low dose may increase the occurrence of secondary malignant neoplasms. For this reasons, the jaw tracking function of the TrueBeam (Varian Medical Systems, Palo Alto, CA) was developed to reduce the leakage and transmission dose of the MLC with existing linear accelerators. But quantitative analysis of the dose reduction has not been verified. Therefore, in the present study, we intended to verify the clinical possibility of utilizing the jaw tracking function in brain tumor with comparison of treatment plans. To accomplish this, 3 types of original treatment plans were made using Eclipse11 (Varian Medical Systems, Palo Alto, CA): 1) beyond 2 cm distance from the Organs At Risk (OARs); 2) within 2 cm distance from the OARs; and 3) intersecting with the OARs. Jaw tracking treatment plans were also made with copies of the original treatment planning using Smart LMC Version 11.0.31 (Varian Medical Systems, Palo Alto, CA). A comparison between the 2 types of treatment planning methods was performed using the difference of the mean dose and maximum dose to the OARs in cumulative Dose Volume Histogram (DVH). In the DVH comparison, the maximum difference of 0.5 % was observed between the planning methods in the case of over 2 cm distance, and the maximum of 0.6 % was obtained for within the 2 cm distance. For the case intersecting with the OAR, the maximum difference of 2 % was achieved. According to these results, it could be realized that the differences of mean dose and maximum dose to the OARs was larger when the OARs and PTV were closer. Therefore, treatment plans with the jaw tracking function consistently affected the dose reduction and the clinical possibility could be verified.

• Progress in Medical Physics
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• v.34 no.2
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• pp.15-22
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• 2023

This study compared the dose calculated using the electron Monte Carlo (eMC) dose calculation algorithm employing the old version (eMC V13.7) of the Varian Eclipse treatment-planning system (TPS) and its newer version (eMC V16.1). The eMC V16.1 was configured using the same beam data as the eMC V13.7. Beam data measured using the VitalBeam linear accelerator were implemented. A box-shaped water phantom (30×30×30 cm³) was generated in the TPS. Consequently, the TPS with eMC V13.7 and eMC V16.1 calculated the dose to the water phantom delivered by electron beams of various energies with a field size of 10×10 cm². The calculations were repeated while changing the dose-smoothing levels and normalization method. Subsequently, the percentage depth dose and lateral profile of the dose distributions acquired by eMC V13.7 and eMC V16.1 were analyzed. In addition, the dose-volume histogram (DVH) differences between the two versions for the heterogeneous phantom with bone and lung inserted were compared. The doses calculated using eMC V16.1 were similar to those calculated using eMC V13.7 for the homogenous phantoms. However, a DVH difference was observed in the heterogeneous phantom, particularly in the bone material. The dose distribution calculated using eMC V16.1 was comparable to that of eMC V13.7 in the case of homogenous phantoms. The version changes resulted in a different DVH for the heterogeneous phantoms. However, further investigations to assess the DVH differences in patients and experimental validations for eMC V16.1, particularly for heterogeneous geometry, are required.

• The Journal of Korean Society for Radiation Therapy
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• v.31 no.2
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• pp.75-81
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• 2019

Purpose: Tomo therapy and Proton therapy treatment plans for the treatment of prostate cancer patients were established, and the characteristics of dose distribution according to beam delivery method using Tomo therapy IMRT method and Proton therapy PBS method to compare and analyze the treatment effect were sought. Materials and Methods: Tomo IMRT treatment plan and Proton PBS treatment plan were established using the Hi.art planning station 5.1.1.6 of Tomo therapy and Eclipse 13.7 of VARIAN for three prostate cancer patients who were treated with radiotherapy only for radical purposes without surgery. For the evaluation of two treatment plans, the average dose (Dmean) and maximum dose (Dmax) of PGTV were calculated from dose volume histogram (DVH) to confirm the coverage and calculate CI and HI. In OAR evaluation, the dose received from the rectal volume 25% and the dose received from the bladder were evaluated to compare the normal long-term protection effect. Results: The mean maximum doses of the three patients were 71.4Gy, 75.3Gy and the mean doses were 70.4Gy and 72.8Gy in the DVH of the Tomo IMRT and Proton PBS. The CI was 1.16 and 1.31, and the HI was 0.04 and 0.12 respectively, and the Tomo IMRT was superior to the Proton PBS in dose suitability. Conclusion: The mean dose of PGTV in prostate cancer patients was 3.4% higher in Proton PBS than in Tomo IMRT. This is because the Dose suitability of Tomo IMRT was better, but it is considered to be a small difference to be seen as a significant result. However, the results of the two methods were 51.2% in D 25% and 55.7% less in the average dose of bladder, which could reduce the side effects of patients in proton PBS.

• Radiation Oncology Journal
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• v.30 no.1
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• pp.27-35
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• 2012

Purpose: To evaluate the effect of common three photon energies (6-MV, 10-MV, and 15-MV) on intensity-modulated radiation therapy (IMRT) plans to treat prostate cancer patients. Materials and Methods: Twenty patients with prostate cancer treated locally to 81.0 Gy were retrospectively studied. 6-MV, 10-MV, and 15-MV IMRT plans for each patient were generated using suitable planning objectives, dose constraints, and 8-field setting. The plans were analyzed in terms of dose-volume histogram for the target coverage, dose conformity, organs at risk (OAR) sparing, and normal tissue integral dose. Results: Regardless of the energies chosen at the plans, the target coverage, conformity, and homogeneity of the plans were similar. However, there was a significant dose increase in rectal wall and femoral heads for 6-MV compared to those for 10-MV and 15-MV. The $V_{20Gy}$ of rectal wall with 6-MV, 10-MV, and 15-MV were 95.6%, 88.4%, and 89.4% while the mean dose to femoral heads were 31.7, 25.9, and 26.3 Gy, respectively. Integral doses to the normal tissues in higher energy (10-MV and 15-MV) plans were reduced by about 7%. Overall, integral doses in mid and low dose regions in 6-MV plans were increased by up to 13%. Conclusion: In this study, 10-MV prostate IMRT plans showed better OAR sparing and less integral doses than the 6-MV. The biological and clinical significance of this finding remains to be determined afterward, considering neutron dose contribution.

• The Journal of Korean Society for Radiation Therapy
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• v.25 no.1
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• pp.1-8
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• 2013

Purpose: A selection of proper energy in treatment planning is very important because of having different dose distribution in body as photon energy. In generally, the low energy photon has been used in intensity-modulated radiation therapy (IMRT) for head and neck (H&N) cancer. The aim of this study was to evaluate the effect of partially used high energy photon at posterior oblique fields on IMRT plan for H&N cancer. Materials and Methods: The study was carried out on 10 patients (nasopharyngeal cancer 5, tonsilar cancer 5) treated with IMRT in Seoul National University Bundang Hospital. CT images were acquired 3 mm of thickness in the same condition and the treatment plan was performed by Eclipse (Ver.7.1, Varian, Palo Alto, USA). Two plans were generated under same planing objectives, dose volume constraints, and eight fields setting: (1) The low energy plan (LEP) created using 6 MV beam alone, (2) the partially used high energy plan (PHEP) created partially using 15 MV beam at two posterior oblique fields with deeper penetration depths, while 6 MV beam was used at the rest of fields. The plans for LEP and PHEP were compared in terms of coverage, conformity index (CI) and homogeneity index (HI) for planning target volume (PTV). For organs at risk (OARs), $D_{mean}$ and $D_{50%}$ were analyzed on both parotid glands and $D_{max}$, $D_{1%}$ for spinal cord were analyzed. Integral dose (ID) and total monitor unit (MU) were compared as addition parameters. For the comparing dose to normal tissue of posterior neck, the posterior-normal tissue volume (P-NTV) was set on the patients respectively. The $D_{mean}$, $V_{20Gy}$ and $V_{25Gy}$ for P-NTV were evaluated by using dose volume histogram (DVH). Results: The dose distributions were similar with regard to coverage, CI and HI for PTV between the LEP and PHEP. No evident difference was observed in the spinal cord. However, the $D_{mean}$, $D_{50%}$ for both parotid gland were slightly reduced by 0.6%, 0.7% in PHEP. The ID was reduced by 1.1% in PHEP, and total MU for PHEP was 1.8% lower than that for LEP. In the P-NTV, the $D_{mean}$, $V_{20Gy}$ and $V_{25Gy}$ of the PHEP were 1.6%, 1.8% and 2.9% lower than those of LEP. Conclusion: Dose to some OARs and a normal tissue, total monitor unit were reduced in IMRT plan with partially used high energy photon. Although these reduction are unclear how have a clinical benefit to patient, application of the partially used high energy photon could improve the overall plan quality of IMRT for head and neck cancer.

• Radiation Oncology Journal
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• v.15 no.4
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• pp.287-296
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• 1997

Purpose : This is study of whether 3-D conformal radiotherapy for carcino-mas of the ethmoid sinus were better than those treated with conventional 2-D plan, Materials and Methods : The 3-D conformal treatment Plans were compared with conventional 2-D plans in 4 patients with malignancy of the ethmoid sinus. Isodose distribution, dose statistics, and dose volume histogram of the planning target volume were used to evaluate differences between 2-D and 3-D plans. In addition. the risk of radiation exposure of surrounding normal critical organs are evaluated by means of point dose calculation and dose volume histogram. Results : 3-D conformal treatment plans for each patient that the better tumor coverages by the planning target volume with improved dose homo-geneity, compared to 2-D conventional treatment Plans in the same Patient. On the other hand, the radiation dose distributions to the surrounding nor-mal tissue organs, such as the orbit and optic nerves are not significantly reduced with our technique, but a substantial sparing in the brain stem and optic chiasm for each patient. Conclusion : Our findings represented the potential advantage of 3-D treatment planning for dose homogeniety as well as sparing of the normal tissue surrounding the tumor. However, further investigational studies are required to define the clinical benefit.

• 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.