Could X-ray microbeams inhibit angioplasty-induced restenosis in the rat carotid artery?
BACKGROUND
Parallel, thin (<100 microm) planes of synchrotron-generated X rays, have been shown to spare normal tissues and preferentially damage tumors in animal models. The aim of the present study was to assess the effect of such microbeams directed unidirectionally on angioplasted rat carotid arteries.


METHODS
Three groups of Sprague-Dawley rats were studied: (a) rats with normal, untreated arteries, (b) rats treated by balloon angioplasty, but not irradiated, and (c) rats treated with balloon angioplasty and exposed to single fraction, unidirectional, parallel, microbeams an hour after angioplasty. The microbeam array, 15 mm widex7.6 mm high, consisting of 27-microm-wide beam slices, spaced 200 microm center-to-center laterally traversed the damaged artery. The in-depth in-beam dose was 150 Gy, the "valley" dose (dose midway between microbeams resulting mainly from X-ray scattering) was 4.5 Gy on average, and the "integrated" (averaged) dose was 26 Gy.


RESULTS
Microbeam irradiation, as given in the present study, was tolerated, but was insufficient to significantly suppress the neointimal hyperplasia.


CONCLUSIONS
The microbeam dose used is considered low. Dose escalation would be necessary to reach conclusive results regarding the X-ray microbeam efficacy to control restenosis.
Dilmanian
F A
FA
Medical Department, Brookhaven National Laboratory, Upton, NY 11973, USA.
Kalef-Ezra
J
J
Petersen
M J
MJ
Bozios
G
G
Vosswinkel
J
J
Giron
F
F
Ren
B
B
Yakupov
R
R
Antonakopoulos
G
G
D000800:Angioplasty, Balloon / Q000009:adverse effects*; D000818:Animals; D017536:Carotid Artery, Common / Q000473:pathology* / Q000528:radiation effects / Q000601:surgery*; D016893:Carotid Stenosis / Q000628:therapy*; D004195:Disease Models, Animal; D004307:Dose-Response Relationship, Radiation; D006083:Graft Occlusion, Vascular / Q000209:etiology* / Q000532:radiotherapy*; D006965:Hyperplasia / Q000209:etiology / Q000532:radiotherapy; D008955:Models, Cardiovascular; D051381:Rats; D017207:Rats, Sprague-Dawley; D017539:Tunica Intima / Q000473:pathology / Q000528:radiation effects; D014965:X-Rays