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Modelling of a ¹⁸⁸W/¹⁸⁸Re beta line source for coronary brachytherapy by means of EGS4 Monte Carlo simulations

PHYSICS IN MEDICINE AND BIOLOGY 2000年第5期45卷 1319-1334页

作者： Clarijs, MC Bos, AJJ van Eijk, CWE Schaart, DR Delft Univ Technol Inst Interfac Reactor Radiat Technol Grp NL-2629 JB Delft Netherlands

In this paper, we present results from three different simulation models that are used to determine the dose distribution around a W-188/Re-188 coronary brachytherapy source with EGS4 Monte Carlo simulations. The three models are found to give similar results within 10%. Agreement was found with experimental data from measurements in a PMMA phantom. It has been shown that in the therapeutically relevant region the beta line source can be characterized by the radial depth-dose distribution in water.

关键词：血管成形术气囊冠状动脉生物物理学现象生物物理学近距离放射疗法/方法近距离放射疗法/统计学和数值数据冠状血管/辐射效应模型理论蒙特卡罗法体模显象术聚甲基异丁烯酸放射性同位素/治疗应用铼/治疗应用钨/治疗应用人类

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Vascular repair after balloon overstretch injury in porcine model effects of intracoronary radiation

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JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY 2000年第4期36卷 1389-1395页

作者： Cottin, Y Kollum, M Chan, R Bhargava, B Vodovotz, Y Waksman, R Washington Hosp Ctr Inst Cardiovasc Res Vasc Brachytherapy Inst Washington DC 20010 USA Washington Hosp Ctr Dept Radiat Oncol Washington DC 20010 USA

OBJECTIVES The purpose of this study was to evaluate the effect of IR on thrombus formation and dissection repair following overstretch balloon injury in porcine coronary arteries. BACKGROUND Exposure of blood to the injured arterial wall after percutaneous transluminal coronary angioplasty (PTCA) induces thrombus formation and inflammation in the dissection plane. Neointima formation is related to smooth muscle cell (SMC) proliferation and migration into the preformed thrombus. Intracoronary radiation (IR) with doses of 10 to 25 Gy using either beta or gamma emitters can prevent neointima accumulation by reducing SMC proliferation. However, there are some indications that IR may delay the process of dissection repair after PTCA. The purpose of this study was to evaluate the effect of IR on thrombus formation and dissection repair after overstretch balloon injury in porcine coronary arteries. METHODS Forty porcine coronaries were injured by balloon overstretch followed by either 0 or 18 Gy of Y-90 prescribed to 1.2 mm from the balloon center. The animals were euthanized 14 days after treatment, and intimal area (IA) and IA corrected for medial fracture length (IA/FL) were quantified by digital image analysis. Dissections were quantified by tracing the length, thickness and area behind the dissection flap. The rate of dissections was calculated for each group. Thrombi were identified and designated as intraluminal thrombus or thrombus within dissection planes (mural thrombus), and area measurements were obtained. RESULTS The irradiated group showed a significant reduction of IA/FL (0.55 +/- 0.29 vs. 0.05 +/- 0.09;p < 0.001). No difference was observed in the rare of dissection between control and irradiated arteries (77% vs. 88%, respectively). The control group showed a smaller dissection area (0.19 +/- 0.28 mm(2) vs. 0.32 +/- 0.29 mm;p < 0.05) with smaller mural thrombi (0.03 +/- 0.01 mm(2) vs. 0.29 +/- 0.30 mm2;p < 0.001). A strong correlation between dissection a

关键词：血管成形术气囊冠状动脉/副作用近距离放射疗法/方法冠状动脉血栓形成/病因学冠状动脉血栓形成/病理学冠状动脉血栓形成/放射疗法冠状血管/损伤冠状血管/病理学冠状血管/辐射效应疾病模型动物猪血管内膜/病理学血管内膜/辐射效应动物

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Intravascular ultrasound volumetric assessment of intimal hyperplasia in stents treated with intracoronary radiation

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AMERICAN JOURNAL OF CARDIOLOGY 1999年第7期84卷 850-+页

作者： Limpijankit, T Waksman, P Yock, PG Fitzgerald, PJ Stanford Univ Med Ctr Dept Med Div Cardiovasc Med Stanford CA 94305 USA Washington Hosp Ctr Dept Med Div Cardiol Washington DC 20010 USA

Iridium-192 (gamma)-radiation is effective in preventing recurrent in-stent restenosis by reducing neointimal hyperplasia;ls illustrated by intravascular ultrasound study and plaque area-length plot. This analytic technique will further our understanding of vessel behavior to radiant energy source both inside and outside the stented coronary artery segments.

关键词：缩窄病理性冠状血管/病理学冠状血管/辐射效应冠状血管/超声检查增生图像处理计算机辅助支架血管内膜/病理学血管内膜/辐射效应血管内膜/超声检查人类

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The effects of intracoronary brachytherapy on the natural history of postangioplasty dissections

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JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY 2000年第1期36卷 59-64页

作者： Meerkin, D Tardif, JC Bertrand, OF Vincent, J Harel, F Bonan, R Montreal Heart Inst Montreal PQ H1T 1C8 Canada Shaare Zedek Med Ctr Dept Cardiol Jerusalem Israel Novoste Corp Norcross GA USA Fonds Rech Sante Quebec Montreal PQ Canada

OBJECTIVES The aim of this study was to determine the natural history of postangioplasty intravascular ultrasound (IVUS)-detectcd dissections and to assess the influence of intracoronary beta-radiation on dissection resolution. BACKGROUND Intracoronary radiotherapy is considered to impair exaggerated vessel healing. Conversely, excessive healing impairment may increase the risk of complications due to unhealed dissection. Alternatively, residual dissection may represent an innocent marker of adequate therapy. METHODS Immediate postangioplastic and six-month follow-up IVUS studies of 94 patients in the IVUS substudy of the: MultiVitamins and Probucol (MVP) trial and 26 nonstented patients in the Beta Energy Restenosis Trial (BERT) were analyzed for the presence or absence of dissection. RESULTS Of the 28 patients with postangioplasty dissections in MVP, only one had evidence of residual dissection at six months (95% confidence interval [CT] for failure rate 0.2%;20.2%). Conversely, 9 of 16 dissections had healed in BERT (95% CI for failure rate 30.6%;79.2%) (p < 0.0002). Nevertheless, an index based on dissection are and length demonstrated improvement in the irradiated patients. Irradiated patients with residual dissections showed significant increase in lumen area at six-months (5.10 +/- 0.98 to 7.11 +/- 2.61 mm(2), p < 0.02) not noted when there was resolution of the: dissection (6.03 +/- 2.38 to 6.36 +/- 3.33 mm(2), p = NS). In both groups the external elastic membrane area was unchanged at follow-up. CONCLUSION Resolution appears to be the natural history of IVUS-detected dissections in most cases. Significant resolution of dissection occurs following intracoronary beta-radiation as reflected in reduced dissection index at six-months in these patients, although significant impairment of vessel wall healing was noted. (J Am Coil Cardiol 2000;36:59-64) (C) 2000 by the American College of Cardiology.

关键词：动脉瘤夹层/诊断显像动脉瘤夹层/病因学动脉瘤夹层/放射疗法血管成形术气囊冠状动脉/副作用 β粒子/治疗应用近距离放射疗法/方法冠状动脉瘤/诊断显像冠状动脉瘤/病因学冠状动脉瘤/放射疗法冠状血管/诊断显像冠状血管/辐射效应前瞻性研究治疗结果超声检查介入性女(雌)性人类男(雄)性中年人

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Late total occlusion after intracoronary brachytherapy for patients with in-stent restenosis

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JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY 2000年第1期36卷 65-68页

作者： Waksman, R Bhargava, B Mintz, GS Mehran, R Lansky, AJ Satler, LF Pichard, AD Kent, KM Leon, MB Washington Hosp Ctr Cardiac Catheterizat Labs Washington DC 20010 USA

OBJECTIVES The study sought to determine the incidence and predictors of late total occlusion (LTO, >30 days) in-patients with ill-stent restenosis who were treated with intracoronary radiation. BACKGROUND Intracoronary radiation both with beta and gamma emitters has been shown to reduce recurrent in-stent restenosis. METHODS We reviewed the records of 473 patients who presented with in-stent restenosis and who were enrolled in various radiation protocols, whether randomized to placebo versus radiation or entered into registries. There were 165 placebo and 308 radiated patients, including both gamma and beta emitters. Maximum dose to the Vessel wall was 30 to 55 Gy. Following radiation, all patients received antiplatelet therapy with aspirin and either ticlopidine or clopidogrel for one month. All patients completed at least six months of angiographic follow-up. RESULTS The LTO was documented in 28 patients (9.1%) from the irradiated group versus 2 placebo patients (1.20%), p < 0.0001. The LTO rates were similar across studies and emitters. In the irradiated group, LTO presented as acute myocardial infarction in 12 patients (43%), unstable angina in 14 (50%), and asymptotic in 2 (7%). Mean time to LTO was 5.4 +/- 3.2 months in the irradiated group versus 4.5 +/- 2.1 in placebo patients (p = NS). The overall rate of restenting for the entire study group at the time of radiation was 48.6%. Importantly, new stents were placed in 82% of the irradiated and in 100% of the placebo patients who presented with LTO. Multivariate analysis determined that new stenting was the main predictor of LTO. CONCLUSION Intracoronary radiation for patients with in-stent restenosis is associated with a high rate of LTO. Restenting may contribute late thrombosis. Prolonged antiplatelet therapy (up to six months) should be considered for these patients. (J Am Cell Cardiol 2000;36:65-8) (C) 2000 by the American College of Cardiology.

关键词：血管成形术气囊冠状动脉/副作用近距离放射疗法/副作用冠状血管造影术冠心病/诊断显像冠心病/病因学冠心病/治疗冠状血管/辐射效应假体失效复发支架时间因素治疗失败女(雌)性人类男(雄)性中年人

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