OBJECTIVETo investigate the effect on the dose distribution of source position displacement with the target region margin in catheter-based 192Ir line source endovascular brachytherapy.

METHODDose rate distribution along longitudinal axes was estimated by the formula recommended by AAPM No.60 and No. 43.

RESULTSIn the two cases of source displacement (1.1 and 5 mm) doses of target region margin was decreased dramatically (at most 53.9% and 565.8% respectively) were compared to that of no source displacement, and the affected range was 6 mm and 9 mm respectively.

CONCLUSIONSource displacement will lead to the decrease of dose in target region margin.

Animals ; Brachytherapy ; methods ; Coronary Restenosis ; radiotherapy ; Coronary Vessels ; radiation effects ; Iridium Radioisotopes ; therapeutic use ; Radiotherapy Dosage

Angioplasty, Balloon, Coronary ; methods ; Coronary Restenosis ; prevention & control ; radiotherapy ; Drug-Eluting Stents ; adverse effects ; Humans ; Iridium ; Rhenium ; Xenon Isotopes

Since the introduction of percutaneous transluminal coronary angioplasty, restenosis has remained the most challenging problem facing interventional cardiologist. Intravascular radiation is a feasible and promising adjunctive therapy in restenosis treatment by suppressing both neointimal proliferation and constrictive remodeling, while there are growing concerns about its long-term effects and complications in clinical perspectives as well as dosing and paradoxical stimulation. Current comments on them may well favor the choice of comprehensive treatment protocol for clinicians.
Angioplasty, Balloon, Coronary ; adverse effects ; Animals ; Brachytherapy ; adverse effects ; methods ; Coronary Restenosis ; prevention & control ; radiotherapy ; Coronary Vessels ; radiation effects ; Humans ; Stents ; adverse effects ; Treatment Outcome

BACKGROUND: Restenosis after percutaneous coronary intervention (PCI) is a matter that still remains to be resolved. Herein, the inhibitory effect of locally delivered (99m) Tc-HMPAO (hexamethyl propylene amine oxime) on neointimal hyperplasia after coronary stenting was examined in a pocine model, and its safety and efficacy observed in patients with coronary stent restenosis. METHODS: After a stent overdilation injury, local radioisotope delivery using (99m) Tc-HMPAO was applied to one coronary artery (Group I) and control therapy to another (Group II) in each of 10 pigs. Follow-up coronary angiogram (CAG) and histopathologic assessment were performed 4 weeks after stenting. Eleven patients (10 males and one female, 62.4 +/- 5.7 years of age) underwent local administration of 30 mCi/ 2 mL (99m) Tc-HMPAO shortly after PCI, via a Dispatch CatheterTM, followed by a whole body scan to evaluate the distribution of the (99m) Tc-HMPAO, as well as a thallium-201 (Tl-201) myocardial scan to evaluate myocardial perfusion. The major adverse cardiac events (MACE) were assessed during a one-year clinical follow-up. RESULTS: On histopathological analysis, the neointimal areas were 1.2 +/- 0.6 and 2.7 +/- 0.4 mm2 (p=0.002), and the histopathological areas of stenosis were 27.16.3 and 53.4 +/- 5.2% in Groups I and II (p=0.001), respectively. In the clinical study, there was no in-hospital MACE. On a quantitative coronary angiographic analysis, the minimal luminal diameter was increased from 0.4 +/- 0.3 to 2.9 +/- 0.2 mm, and diameter stenosis decreased from 84.2 +/- 9.5 to 16.3 +/- 11.0% following PCI. Follow-up CAG was performed in 9 cases (81.8%) and restenosis occurred in 2 (22.2%). On a follow-up CAG, the minimal luminal diameter, diameter stenosis rate, lumen loss and loss index were 2.0 +/- 0.8 mm, 27.7 +/- 2.9%, 0.7 +/- 0.7 mm and 0.2 +/- 0.3, respectively. During the one-year clinical follow-up there were no cases of death or acute MI, but two cases of target vessel revascularization (18.2%). CONCLUSION: Local delivery of (99m) Tc-HMPAO, a novel radiotherapy, can be used safely and effectively for coronary stent restenosis.
Angioplasty, Transluminal, Percutaneous Coronary ; Animals ; Brachytherapy/*methods ; Coronary Angiography ; Coronary Restenosis/*radiotherapy ; Female ; Humans ; Male ; Middle Aged ; Radiopharmaceuticals/*therapeutic use ; Research Support, Non-U.S. Gov't ; *Stents ; Swine ; Technetium Tc 99m Exametazime/*therapeutic use