نتایج جستجو برای: intravascular brachytherapy
تعداد نتایج: 24513 فیلتر نتایج به سال:
SCIENTIFIC BACKGROUND Percutaneous transluminal angioplasties (PTA) through balloon dilatation with or without stenting, i.e. vessel expansion through balloons with or without of implantation of small tubes, called stents, are used in the treatment of peripheral artery occlusive disease (PAOD). The intravascular vessel irradiation, called intravascular brachytherapy, promises a reduction in the...
Serial intravascular ultrasound (IVUS) studies have shown that restenosis in nonstented lesions and late lumen loss in reference segments contiguous with both stented and nonstented lesions is a balance between arterial remodeling and neointimal hyperplasia. Conversely, in-stent restenosis (ISR) is neointimal hyperplasia.1,2 The present review focuses on lessons learned from IVUS about mechanis...
While simple, intravascular brachytherapy (IVB) presents a considerable potential for harm to the patient. The medical physicist maintains the responsibility to minimize the likelihood of operational problems or dosimetric errors. The principals for safe operation remain the same as with any radiotherapy treatment: to deliver the correct dose, to the correct location, safety. To develop an effe...
BACKGROUND AND OBJECTIVE The most common intravascular brachytherapy sources include (32)P, (188)Re, (106)Rh and (90)Sr/(90)Y. In this research, skin absorbed dose for different covering materials in dealing with these sources were evaluated and the best covering material for skin protection and reduction of absorbed dose by radiation staff was recognized and recommended. METHOD Four material...
The high spatial resolution of radiochromic film makes it ideal for dosimetric measurements and dose distributions in regions of high dose gradient. Intensity-modulated radiation therapy, intravascular brachytherapy, and eye-plaque radiation therapy demand precise spatial dosimetric calculations. Such precision is not possible with conventional dosimeters, such as thermoluminescent dosimeters a...
Very late thrombosis in an implanted bare-metal stent is a very uncommon event outside the context of brachytherapy and few data about its pathophysiology are available. We performed an intravascular ultrasound study during primary angioplasty in five patients with very late bare-metal stent thrombosis and carried out a histological analysis of the material removed by manual thrombectomy. The m...
We have been studying brachytherapy planning with the objective of minimizing the maximum deviation of the delivered dose from prescribed dose bounds for treatment volumes. A general framework for optimal treatment planning is presented and the minmax optimization is formulated as a linear program. Dose rate calculations are based on the dosimetry formulation of the American Association of Phys...
BACKGROUND Scarce data exist concerning the long-term effect of percutaneous transluminal renal angioplasty (PTRA) enhanced with intravascular gamma brachytherapy (IVBT) in patients with renovascular hypertension. METHODS Seventy one patients aged 52 +/- 8 years with refractory renovascular hypertension were randomized to Group I (PTRA + IVBT) or Group II (PTRA). For the IVBT procedure, the P...
Background—Intravascular brachytherapy is being applied more and more in patients with coronary artery disease for the prevention of restenosis subsequent to balloon angioplasty, in particular after stent implantation. Several radiation sources ( and -emitters) are available in clinical routine. It was the purpose of this study to compare the radiation doses at the level of the adventitia in di...
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