• Title/Summary/Keyword: Intravascular brachytherapy

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Conceptual Source Design and Dosimetric Feasibility Study for Intravascular Treatment: A Proposal for Intensity Modulated Brachytherapy (혈관내 방사선치료를 위한 이론적 선원 설계 및 선량적 관점에서의 적합성 연구: 출력변조를 이용한 근접치료에 대한 제안)

  • Kim Siyong;Han Eunyoung;Palta Jatinder R.;Ha Sung W.
    • Radiation Oncology Journal
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    • v.21 no.2
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    • pp.158-166
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    • 2003
  • Purpose: To propose a conceptual design of a novel source for intensity modulated brachytherapy. Materials and Methods: The source design incorporates both radioactive and shielding materials (stainless steel or tungsten), to provide an asymmetric dose intensity in the azimuthal direction. The intensity modulated intravascular brachytherapy was performed by combining a series of dwell positions and times, distributed along the azimuthal coordinates. Two simple designs for the beta-emitting sources, with similar physical dimensions to a $^{90}Sr/Y$ Novoste Beat-Cath source, were considered in the dosimetric feasibility study. In the first design, the radioactive and materials each occupy half of the cylinder and in the second, the radioactive material occupies only a quater of the cylinder. The radial and azimuthal dose distributions around each source were calculated using the MCNP Monte Carlo code. Results: The preliminary hypothetical simulation and optimization results demonstrated the 87$\%$ difference between the maximum and minimum doses to the lumen wall, due to off-centering of the radiation source, could be reduced to less than 7$\%$ by optimizing the azimuthal dwell positions and times of the partially shielded intravascular brachytherapy sources. Conclusion: The novel brachytherapy source design, and conceptual source delivery system, proposed in this study show promising dosimetric characteristics for the realization of intensity modulated brachytherapy in intravascular treatment. Further development of this concept will center on building a delivery system that can precisely control the angular motion of a radiation source in a small-diameter catheter.

Intracoronary Radiation Therapy Using Re-188 after percutaneous Coronary Angioplasty (경피적 관동맥혈관성형술 후 Re-188을 이용한 혈관 내 방사선조사요법)

  • Chae, In-Ho;Lee, Myoung-Mook;Lee, Dong-Soo
    • 대한핵의학회:학술대회논문집
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    • 1999.05a
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    • pp.228-241
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    • 1999
  • Percutaneous coronary angioplasty is well established therapeutic modality in the management of coronary artery disease. However, the high restenosis rate of 30 to 50% limits its usefulness. The principal mechanism of restenosis, intimal hyperplasia, is the proliferative response of vessel wall to injury, which consists largely of smooth muscle cells. A large body of animal investigations and a limited number of clinical studies have established the ability of ionizing radiation to reduce neointimal proliferation and restenosis rate significantly. Human studies have been reported that intravascular radiation after first restenosis inhibits a second restenosis. Encouraged by these reports, we are also conducting a double blind, placebo-controlled, randomized trial to evaluate this new therapeutic modality in patients with coronary artery stenosis. The objective of our trial is to determine the safety and efficacy of catheter-based solutional beta emitting radioisotope system in preventing restenosis after angioplasty. This review describes the vascular brachytherapy systems and isotopes that have been utilized in the initial clinical trials performed in this area of post PTCA coronary restenosis. The results of many worldwide ongoing clinical trials will determine whether this new technology will change the future practice of vascular intervention.

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Values of Three Different Preoperative Regimens in Comprehensive Treatment For Young Patients with Stage Ib2 Cervical Cancer

  • Zhao, Yi-Bing;Wang, Jin-Hua;Chen, Xiao-Xiang;Wu, Yu-Zhong;Wu, Qiang
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.4
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    • pp.1487-1489
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    • 2012
  • Objective: To compare the clinical efficacy of concurrent chemoradiotherapy, neoadjuvant chemotherapy, and intracavity brachytherapy in comprehensive treatment for young patients with stage Ib2 cervical cancer. Methods: One hundred and twelve young patients with stage Ib2 cervical cancer were enrolled retrospectively in our hospital from January 2003 to June 2005. They were categorized into three groups according to preoperative regimens, including the concurrent chemoradiotherapy group (Group 1, n=38), the neoadjuvant chemotherapy (Group 2, n=49), and the intracavity brachytherapy group (Group 3, n=25). Radical hysterectomy was performed following these regimens. Chemotherapy and radiotherapy were given according to pelvic lymph node metastasis, deep cervical stromal invasion, intravascular cancer emboli, histological grading, vaginal stump and positive surgical margin. Results: The cancer disappearance and superficial muscle invasion rates were statistically significantly better in the concurrent chemoradiotherapy group than in the other two groups (P<0.01). No statistically significant difference was noted in the deep muscle invasion rate, surgical time and intraoperative blood loss among three groups, but significantly more postoperative complications occurred in the concurrent chemoradiotherapy group. The 2-year pelvic recurrence was statistically significantly lower in the concurrent chemoradiotherapy group compared to other two groups, while the 5-year survival was higher. Conclusion: Concurrent chemoradiotherapy is efficacious for young patients with stage Ib2 cervical cancer.