To investigate the suitability of 144Ce for both interstitial and intravascular brachytherapy applications. Monte Carlo calculations of radial dose rate distributions in water were performed for 144Ce in a spring-shaped source and compared with two commonly used interstitial and intravascular sources, 192Ir and 32P. 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, 144Ce presents dosimetric advantages over 192Ir 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 144Ce might also be advantageous over 192Ir. For intravascular brachytherapy, 144Ce permits the treatment of larger arteries as compared with 32P, 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 144Ce 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 192Ir and 32P, as well as by such characteristics as half-life and specific activity. [All rights reserved Elsevier]