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(Circulation. 2001;103:1793.)
© 2001 American Heart Association, Inc.

Basic Science Reports

Liquid-Filled Balloon Brachytherapy Using ⁶⁸Ga Is Effective and Safe Because of the Short 68-Minute Half-Life

Results of a Feasibility Study in the Porcine Coronary Overstretch Model

Hans-Peter Stoll, MD; Gary D. Hutchins, PhD; Wendy L. Winkle, BS; Anne T. Nguyen, MS; Dongming Hou, MD, PhD; C. Robert Appledorn, PhD; Bernd Romeike, MD; Keith L. March, MD, PhD

From the Krannert Institute of Cardiology (H.-P.S., A.T.N., D.H., K.L.M.); the PET Facility, Department of Radiology, Indiana University School of Medicine (G.D.H., W.L.W., C.R.A.); and the Richard L. Roudebush Veterans Administration Medical Center (K.L.M.), Indianapolis, Ind; and the Department of Neuropathology, University Hospital, Homburg/Saar, Germany (B.R.).

Correspondence to Hans-Peter Stoll, MD, Innere Medizin III, Kardiologie, Universitätskliniken des Saarlandes, 66421 Homburg/Saar, Germany. E-mail inhsto{at}med-rz.uni-saarland.de

Background—Liquid-filled balloons for coronary brachytherapy provide significant advantages over solid sources in dose homogeneity but carry the risk of life-threatening radiointoxication after balloon rupture and laboratory contamination in case of a spill. We hypothesized that the positron emitter ⁶⁸Ga, with a half-life of only 68 minutes, was well suited to overcome these safety obstacles while providing full therapeutic efficacy.

Methods and Results—The feasibility, efficacy, and safety of ⁶⁸Ga liquid-filled balloon brachytherapy were investigated in the porcine coronary overstretch model. Four groups of 5 balloon-induced coronary lesions were irradiated with 8, 12, 16, and 24 Gy targeted to the adventitia. Ten unirradiated lesions served as controls. Segments treated with 16 or 24 Gy exhibited marked suppression of neointimal proliferation at 28-day follow-up, with quantitative parameters of intraluminal proliferation reduced to <20%. This beneficial effect was not compromised by untoward edge effects. Uninjured but irradiated vessels did not show histological signs of radiation damage. The ⁶⁸Ga whole-body dose due to balloon rupture was estimated to be 5 rem/50 mCi treatment activity and compared favorably with that of ¹⁸⁸Re (78 rem/50 mCi).

Conclusions—⁶⁸Ga positron radiation suppresses neointimal proliferation at doses of 16 and 24 Gy. This biological efficacy, coupled with the attractive safety profile, suggests the selection of ⁶⁸Ga as an attractive isotope for liquid-filled balloon brachytherapy.

Key Words: angioplasty • restenosis • radioisotopes