• Radiation Oncology Journal
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• v.15 no.4
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• pp.305-313
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• 1997

Purpose : This is a retrospective study to evaluate the results of radiation therapy and prognostic factors influencing the results in nasopharyngeal carcinoma. Materials and Methods: From October 1989 to May 1996. 56 Patients were treated for nasopharyngeal carcinoma at Department of Radiation On-cology. According to stage, patients were distributed as follows : stage I (2), II (13). II (11), IV (30). Twenty-eight patients were treated with radiation therapy only, 7 patients were treated with neoadiuvant chemotherapy followed by radiation therapy. Twenty-one Patients were treated with radiation therapy and weekly CDDP. After external beam radiotherapy of 60Gy, 46Patients received boost dose with intracavitary radiation and 9 Patients with 3D conformal therapy. One patient received boost dose with 2 dimensional Photon beam therapy. The tumor dose ranged from 69.4Gy to 86.2Gy with median dose of 74.4Gy. The follow-up Period ranged from 5 months to 92 months with a median of 34 months. Results : Forty-seven patients achieved complete response and 8 Patients showed partial response. One Patient showed minimal response. Patterns of failure were as follows : locoregional recurrence (8) and distant metastasis (18). Among these patients, 2 patients failed locoregionally and distantly. The sites of distant metastasis were bone (8), lung (8) and liver (4). Five years survival rate was $67.2\%$ and 5 years disease-free survival rate was $53.6\%$. KPS (P=0.005) and response ol radiation therapy (P=0.0001) were significant prognostic factors for overall survival. KPS (P= 0.02) and response of radiation therapy (P=0.005) were significant Prognostic factors for disease-free survival. Conclusion : This retrospective study showed that distant metastasis was the Predominant pattern of relapse in nasopharyngeal cancer Neoadiuvant chemotherapy or weekly CDOP did not influence the distant metastasis-free survival. For advanced T stage, 3D conformal therapy Provided an improved dose coverage compared to ICR But further follow-up was needed in Patients with 3D conformal therapy to assess the efficacy of this therapy. Development of techniques of radiation therapy to improve locoregional control and of more effective systemic chemotherapy regimen are needed.

• The Journal of Korean Society for Radiation Therapy
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• v.20 no.2
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• pp.115-122
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• 2008

Purpose: The cancer treatment which uses radiation from next year when the X-ray is discovered with the fact that it is started. The radiation treatment technique for a cancer treatment is developed ceaselessly without and it is come and, with advancement of the computer and electromagnetic engineering it joins in and quickly, it was made to do a many development from radiation treatment field. Accordingly, this study is examine in the radiotherapy technique which is developed that importance to therapeutic principles and methods. Materials and Methods: We had investigated record for radiotherapy technique which is developed and we had acquired information widely at clinical experience data. Results: The cancer treatment which uses the radiation of today is repeating a dazzling development. Past the treatment which is two-dimensional it does not correspond in therapeutic objective but currently 3 dimension three-dimensional moulding treatment or centurial control radiation treatment this the fourth dimension therapeutic technique which is in parallel to be introduced the complication solution in compliance with a normal organization protection and the radiation which are a difficult problem of during that time radiation treatment possibly did. Conclusion: 3-dimensional and 4-dimensional modern radiation treatment which is developen is that corresponding in objective of radiation treatment and the evaluation that again it does thick, judges in about the cancer treatment which uses radiation with the fact that the protection of normal organization is almost become accomplished.

• Radiation Oncology Journal
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• v.16 no.3
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• pp.265-274
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• 1998

Purpose : This prospective study has been conducted to assess the value of three dimensional conformal radiation therapy (3DCRT) for lung cancer and to determine its potential advantage over current treatment approaches. Specific aims of this study were to 1) find the most ideal 3DCRT technique 2) establish the maximum tolerance dose that can be delivered with 3DCRT and 3) identify patients at risk for development of radiation pneumonitis. Materials and Methods : Beginning in Nov. 1994, 95 patients with inoperable non-small cell lung cancer (stage I; 4, stage II; 1, stage IIIa; 14, stage IIIb; 76) were entered onto this 3D conformal trial Areas of known disease and elective nodal areas were initially treated to 45 Gy and then using 3DCRT technique 65 to 70 Gy of total dose were delivered to the gross disease. Sixty nine patients received 65 Gy of total dose and 26 received 70 Gy Seventy eight patients (82.1$\%$) also received concurrent MVP chemotherapy. 3DCRT plans were compared with 2D plans to assess the adequacy of dose delivery to target volume, dose volume histograms for normal tissue, and normal tissue complication Probabilities (NTCP). Results : Most of plans (78/95) were composed of non-coplanar multiple (4-8) fields. Coplanar segmented conformal therapy was used in 17 pateints, choosing the proper gantry angle which minimize normal lung exposure in each segment. 3DCRT gave the full dose to nearly 100$\%$ of the gross disease target volume in all patients. The mean NTCP for ipsilateral lung with 3DCRT (range; 0.17-0.43) was 68$\%$ of the mean NTCP with 2D treatment planning (range; 0.27-0.66). DVH analysis for heart showed that irradiated volume of heart could be significantly reduced by non-coplanar 3D approach especially in the case of left lower lobe lesion. Of 95 patients evaluable for response, 75 (79$\%$), showed major response including 25 (26$\%$) with complete responses and 50 (53$\%$) with partial responses. One and two rear overall survivals of stage III patients were 62.6$\%$ and 35.2$\%$ respectively. Twenty percent (19/95) of patients had pneumonitis; Eight patients had grade 1 pneumonitis and 11 other patients had grade 2. Comparison of the average of NTCP for lung showed a significant difference between patients with and without radiation pneumonitis. Average NTCP for Patients without complication was 62$\%$ of those with complications. Conclusions : This study showed that non-coplanar multiple fields (4-8) may be one of the ideal plans for 3DCRT for lung cancer. It also suggested that 3DCRT may provide superior delivery of high dose radiation with reduced risk to normal tissue and that NTCP can be used as a guideline for the dose escalation.

• Radiation Oncology Journal
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• v.20 no.3
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• pp.264-273
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• 2002

Purpose : Three-dimensional radiation dosimetry using magnetic resonance imaging of polymer gel was recently introduced. This dosimetry system is based on radiation induced chain polymerization of acrylic monomers in a muscle equivalent gel and provide accurate 3 dimensional dose distribution. We planned this study to evaluate the clinical value of this 3-dimensional dosimetry. Materials and Methods: The polymer gel poured into a cylindrical glass flask and a spherical glass flask. The cylindrical test tubes were for dose response evaluation and the spherical flasks, which is comparable to the human head, were for isodose curves. T2 maps from MR images were calculated using software, IDL. Dose distributions have been displayed for dosimetry. The same spherical flask of gel and the same irradiation technique was used for film and TLD dosimetry and compared with each other. Results : The R2 of the gel respond linearly with radiation doses in the range of 2 to 15 Gy. The repeated dosimetry of spherical gel showed the same isodose curves. These isodose curves were identical to dose distributions from treatment planning system especially high dose range. In addition, the gel dosimetry system showed comparable or superior results with the film and TLD dosimetry. Conclusion : The 3-dimensional dosimetry for conformal radiation therapy using MRI of polymer gal showed stable and accurate results. Although more studies are needed for convenient clinical application, it appears to be a useful tool for conformal radiation therapy.

• Radiation Oncology Journal
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• v.32 no.3
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• pp.170-178
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• 2014

Purpose: We sought to evaluate the clinical outcomes of 3-dimensional conformal radiation therapy (3D-CRT) for portal vein tumor thrombosis (PVTT) alone in patients with advanced hepatocellular carcinoma. Materials and Methods: We retrospectively analyzed data on 46 patients who received 3D-CRT for PVTT alone between June 2002 and December 2011. Response was evaluated following the Response Evaluation Criteria in Solid Tumors. Prognostic factors and 1-year survival rates were compared between responders and non-responders. Results: Thirty-seven patients (80.4%) had category B Child-Pugh scores. The Eastern Cooperative Oncology Group performance status score was 2 in 20 patients. Thirty patients (65.2%) had main or bilateral PVTT. The median irradiation dose was 50 Gy (range, 35 to 60 Gy) and the daily median dose was 2 Gy (range, 2.0 to 2.5 Gy). PVTT response was classified as complete response in 3 patients (6.5%), partial response in 12 (26.1%), stable disease in 19 (41.3%), and progressive disease in 12 (26.1%). There were 2 cases of grade 3 toxicities during or 3 months after radiotherapy. Twelve patients in the responder group (15 patients) received at least 50 Gy irradiation, but about 84% of patients in the non-responder group received less than 50 Gy. The 1-year survival rate was 66.8% in responders and 27.4% in non-responders constituting a statistically significant difference (p = 0.008). Conclusion: Conformal radiotherapy for PVTT alone could be chosen as a palliative treatment modality in patients with unfavorable conditions (liver, patient, or tumor factors). However, more than 50 Gy of radiation may be required.

• Radiation Oncology Journal
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• v.37 no.4
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• pp.271-278
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• 2019

Purpose: To investigate the differences in treatment outcomes between two radiation techniques, intensity-modulated radiotherapy (IMRT) and three-dimensional conformal radiotherapy (3DCRT). Materials and Methods: We retrospectively analyzed 160 (IMRT = 23, 3DCRT = 137) patients with stage I glottic cancer treated from January 2005 through December 2016. The IMRT was performed with TomoTherapy (16 patients), volumetric-modulated arc therapy (6 patients), and step-and-shoot technique (1 patient), respectively. The 3DCRT was performed with bilateral parallel opposing fields. The median follow-up duration was 30 months (range, 31 to 42 months) in the IMRT group and 65 months (range, 20 to 143 months) in the 3DCRT group. Results: The 5-year overall survival and 3-year local control rates of the 160 patients were 95.7% and 91.4%, respectively. There was no significant difference in 3-year local control rates between the IMRT and 3DCRT groups (94.4% vs. 91.0%; p = 0.587). Thirteen of 137 patients in the 3DCRT group had recurrences. In the IMRT group, one patient had a recurrence at the true vocal cord. Patients treated with IMRT had less grade 2 skin reaction than the 3DCRT group, but this had no statistical significance (4.3% vs. 21.2%; p = 0.080). Conclusion: IMRT had comparable outcomes with 3DCRT, and a trend of less acute skin reaction in stage I glottic cancer patients.

• Progress in Medical Physics
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• v.15 no.4
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• pp.179-185
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• 2004

To deal with tumor motion from respiration is one of the important issues for the advanced treatment techniques, such as the intensity modulated radiation therapy (IMRT), the image guided radiation therapy (IGRT), the three dimensional conformal therapy (3D-CRT) and the Cyber Knife. Studies including the active breath control (ABC) and the gated radiation therapy have been reported. Authors have developed the device for reducing the respiration effects and the diaphragm motions with this device were observed to determined the effectiveness of the device. The device consists of four belts to immobilize diaphragm motion and the vacuum cushion. Diaphragm motions without and with device were monitored fluoroscopically. Diaphragm motion ranges were found to be 1.14 ～ 3.14 cm (average 2.14 cm) without the device and 0.72～1.95 cm (average 1.16 cm) with the device. The motion ranges were decreased 20 ～ 68.4% (average 44.9%.) However, the respiration cycle was increased from 4.4 seconds to 3.7 seconds. The CTV-PTV margin could be decreased significantly with the device developed in this study, which may be applied to the treatments of the tumor sited diaphragm region.

• Journal of Radiation Protection and Research
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• v.44 no.4
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• pp.156-160
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• 2019

Background: To compare the dose of radiation received by the fetus in a pregnant patient irradiated for head and neck cancer using helical tomotherapy and three-dimensional conformal radiation therapy (3DCRT). Materials and Methods: The patient was modeled with a humanoid phantom to mimic a gestation of 26 weeks. Radiotherapy with a total dose of 2 Gy was delivered with both tomotherapy (2.5 and 5.0 cm jaw size) and 3DCRT. The position of the fetus was predicted to be 45 cm from the field edge at the time of treatment. The delivered dose was measured according to the distance from the field edge and the fetus. Results and Discussion: The accumulated dose to the fetus was 1.6 cGy by 3DCRT and 2 and 2.3 cGy by the 2.5 and 5 cm jaw tomotherapy plans. For tomotherapy, the fetal dose with the 2.5 cm jaw was lower than that with the 5 cm jaw, although the radiation leakage was greater for 2.5 cm jaw plan due to the 1.5 fold longer beam-on time. At the uterine fundus, tomotherapy with a 5 cm jaw delivered the highest dose of 2.4 cGy. When the fetus moves up to 35 cm at the 29th week of gestation, the resultant fetal doses for 3DCRT and tomotherapy with 2.5 and 5 cm jaws were estimated as 2.1, 2.7, and 3.9 cGy, respectively. Conclusion: For tomotherapy, scattering radiation was more important due to the high monitor unit values. Therefore, selecting a smaller jaw size for tomotherapy may reduce the fetal dose. however, evaluation of risk should be individually performed for each patient.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.6-8
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• 2002

Intensity modulated radiotherapy (IMRT) is an advanced but expensive form of 3-dimensional conformal radiation therapy technique. While the initial clinical data appear to be promising for some treatment sites, the cost effectiveness of the treatment modality has yet to be justified by long-term clinical outcome. This presentation reviews the potential efficacy and limitation of IMRT in respect of the practicality, dosimetry, and resource aspects. It tries to explore and draw conclusions on the strategies for using this sophisticated and expensive treatment technique from AFOMP perspective.

• Radiation Oncology Journal
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• v.35 no.3
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• pp.208-216
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• 2017

Purpose: To evaluate the feasibility of simultaneous integrated boost intensity-modulated radiotherapy (SIB-IMRT) for preoperative concurrent chemoradiotherapy (PCRT) in locally advanced rectal cancer (LARC), by comparing with 3-dimensional conformal radiotherapy (3D-CRT). Materials and Methods: Patients who were treated with PCRT for LARC from 2015 January to 2016 December were retrospectively enrolled. Total doses of 45 Gy to 50.4 Gy with 3D-CRT or SIB-IMRT were administered concomitantly with 5-fluorouracil plus leucovorin or capecitabine. Surgery was performed 8 weeks after PCRT. Between PCRT and surgery, one cycle of additional chemotherapy was administered. Pathologic tumor responses were compared between SIB-IMRT and 3D-CRT groups. Acute gastrointestinal, genitourinary, hematologic, and skin toxicities were compared between the two groups based on the RTOG toxicity criteria. Results: SIB-IMRT was used in 53 patients, and 3D-CRT in 41 patients. After PCRT, no significant differences were noted in tumor responses, pathologic complete response (9% vs. 7%; p = 1.000), pathologic tumor regression Grade 3 or higher (85% vs. 71%; p = 0.096), and R0 resection (87% vs. 85%; p = 0.843). Grade 2 genitourinary toxicities were significantly lesser in the SIB-IMRT group (8% vs. 24%; p = 0.023), but gastrointestinal toxicities were not different across the two groups. Conclusion: SIB-IMRT showed lower GU toxicity and similar tumor responses when compared with 3D-CRT in PCRT for LARC.