Wahle A, Lopez JJ, Pennington EC, Meeks SL, Braddy KC, Fox JM, Brennan TMH, Buatti JM, Rossen JD, Sonka M:


Effects of Vessel Geometry and Catheter Position on Dose Delivery in Intracoronary Brachytherapy.

Transactions on Biomedical Engineering, IEEE Press

Volume 50, Number 11, Page 1286-1295, November 2003

Study on the impact of vessel curvature and eccentricity of the treatment catheter in intravascular brachytherapy, performed in computer simulated phantoms as well as in-vivo from 3-D models obtained by fusion of intravascular ultrasound and biplane angiography (Paper) (Images) (Links)

Abstract: In-stent restenosis is commonly observed in coronary arteries after intervention. Intravascular brachytherapy has been found effective in reducing the recurrence of restenosis after stent placement. Conventional dosing models for brachytherapy with beta radiation neglect vessel geometry as well as the position of the delivery catheter. This paper demonstrates in computer simulations on phantoms and on in-vivo patient data that the estimated dose distribution varies substantially in curved vessels. In simulated phantoms of 50mm length with a shape corresponding to a 60-180° segment of a respectively sized torus, the average dose in 2mm depth was decreased by 2.70-7.48% at the outer curvature and increased by 2.95-9.70% at the inner curvature as compared to a straight phantom. In-vivo data were represented in a geometrically correct three-dimensional model that was derived by fusion of intravascular ultrasound (IVUS) and biplane angiography. These data were compared to a simplified tubular model reflecting common assumptions of conventional dosing schemes. The simplified model yielded significantly lower estimates of the delivered radiation and the dose variability as compared to a geometrically correct model (p<0.001). The estimated dose in 10 vessel segments of 8 patients was on average 8.76% lower at the lumen/plaque and 6.52% lower at the media/adventitia interfaces (simplified tubular model relative to geometrically correct model). The differences in dose estimates between the two models were significantly higher in the right coronary artery as compared to the left coronary artery (p<0.001).