(144)Ce as a potential candidate for interstitial and intravascular brachytherapy.

Abstract

To investigate the suitability of (144)Ce for both interstitial and intravascular brachytherapy applications. Monte Carlo calculations of radial dose rate distributions in water were performed for (144)Ce in a spring-shaped source and compared with two commonly used interstitial and intravascular sources, (192)Ir and (32)P. The numeric simulations were checked experimentally with a calibrated ionization chamber in a water phantom. Other source characteristics, such as half-life and specific activity, were also compared. For interstitial brachytherapy, (144)Ce presents dosimetric advantages over (192)Ir in terms of higher dose rate at shorter distances and lower irradiation of organs outside the tumor. The source size and shape reduce the anisotropy and the number of dwell positions necessary. The longer half-life of (144)Ce might also be advantageous over (192)Ir. For intravascular brachytherapy, (144)Ce permits the treatment of larger arteries as compared with (32)P, compensates centering errors more effectively, and has a more suitable half-life. The experimental validation showed good agreement (within 10%) with the Monte Carlo simulated dose rate distributions. There are certain potential advantages of using (144)Ce as a source for both interstitial and intravascular brachytherapy. The basis for this finding is provided by the Monte Carlo radial dose rate comparisons with (192)Ir and (32)P, as well as by such characteristics as half-life and specific activity.