Anti-restenotic effect of copper-62 liquid-filled balloon in porcine coronary arteries: novel use of a short half-life positron emitter.
OBJECTIVE
To determine the efficacy of the use of copper-62, a positron emitter with a half-life of 9.7 minutes, as an intracoronary brachytherapy (IRBT) source in the prevention of neointima formation (NF) following overstretch balloon injury (BI) in the porcine model.


METHODS
Sixteen swine were treated after BI to their left anterior descending (LAD), left circumflex (LCX), and/or right coronary artery (RCA). Twelve of the injured arteries received placebo and 10 received 25 Gy, delivered to 0.5 mm from the surface of the treatment balloon filled with liquid (62)Cu. Dosimetry was based on Monte Carlo calculations. Two weeks after treatment, the animals were sacrificed, and the treated coronaries were perfusion-fixed and stained. Intimal area (IA) and medial fracture length (FL) were analyzed by computer-aided histomorphometry.


RESULTS
The ((62)Zn/(62)Cu) generator, together with a rapid concentration process, was successful in delivering the short-lived (62)Cu at the high concentration required for intravascular brachytherapy (IVBT). The fracture length in the two groups was similar (2.10 +/- 0.57; 2.02 +/- 0.77; p = NS). Arteries studied showed significant reduction in NF (IA: 0.23 +/- 0.47 mm(2) vs. 1.08 +/- 0.57 mm(2); p < 0.01. IA/FL = 0.09 +/- 0.17 mm vs. 0.51 +/- 0.21 mm; p < 0.01).


CONCLUSIONS
This study demonstrated that use of liquid (62)Cu as an IVBT source is safe and feasible. All 16 swine tolerated the treatment well with no radiation-induced side effects or symptoms throughout the 2-week period. The isotope delivered the dose necessary to inhibit NF in the porcine coronary BI model.
Chan
R C
RC
Department of Radiation Oncology Washington Hospital Center, Washington, DC, USA.
Lacy
J L
JL
Bhargava
B
B
Collins
S D
SD
Cates
P
P
Cottin
Y
Y
Kollum
M
M
Yang
N
N
Haynes
N G
NG
Martin
C S
CS
Nayak
N
N
Vodovotz
Y
Y
Kim
H
H
Waksman
R
R
D000818:Animals; D001918:Brachytherapy / Q000379:methods*; D002404:Catheterization / Q000009:adverse effects / Q000379:methods*; D003301:Copper Radioisotopes / Q000627:therapeutic use*; D003327:Coronary Disease / Q000473:pathology / Q000517:prevention & control / Q000532:radiotherapy*; D005240:Feasibility Studies; D006207:Half-Life; D009010:Monte Carlo Method; D011853:Radiobiology; D011868:Radioisotopes / Q000627:therapeutic use*; D011874:Radiometry / Q000379:methods; D012211:Rhenium / Q000627:therapeutic use*; D055502:Secondary Prevention; D013552:Swine; D017539:Tunica Intima / Q000293:injuries / Q000473:pathology / Q000528:radiation effects*
D003301:Copper Radioisotopes; D011868:Radioisotopes; D012211:Rhenium