Effectiveness of fractionated external beam radiation in the inhibition of vascular restenosis.
BACKGROUND
From the clinical oncologic experience, fractionation of the radiation dose offers a better therapeutic window, both with respect to effectiveness and unwanted side effects. Thus, we undertook a pilot study in a rodent model, using a single dose of 15 Gy compared with fractionation schedules of 5 or 10 daily applications of 3 Gy.


METHODS
Using a previously described rat angioplasty model, animals were randomly assigned to one of four groups: unilateral balloon injury, sham irradiation; unilateral balloon injury, bilateral 15 Gy single dose irradiation; unilateral balloon injury, bilateral 3 Gy x 5 daily fractions; or unilateral balloon injury, bilateral 3 Gy x 10 daily fractions.


CONCLUSIONS
All three radiation groups demonstrated a clear inhibition of neointimal hyperplasia. We therefore offer evidence for the effectiveness of fractionated radiation as a means to inhibit vascular restenosis in a rat carotid model. However, the 3 Gy x 5 schedule was less effective than either the 3 Gy x 10 schedule or the 15 Gy single dose. This study must be repeated using longer time points to provide proof of principle.
Williams
J P
JP
Department of Radiation Oncology, University of Rochester Medical Center, New York, USA. Jackie_Williams@urmc.rochester.edu
Eagleton
M
M
Hernady
E
E
Schell
M
M
Illig
K
K
Green
R
R
Rubin
P
P
D000818:Animals; D020212:Carotid Artery Injuries / Q000209:etiology / Q000473:pathology / Q000532:radiotherapy; D016893:Carotid Stenosis / Q000473:pathology / Q000517:prevention & control / Q000532:radiotherapy*; D002404:Catheterization / Q000009:adverse effects; D006801:Humans; D006965:Hyperplasia; D008297:Male; D011879:Radiotherapy Dosage; D051381:Rats; D017207:Rats, Sprague-Dawley; D012008:Recurrence