Fluid-jet deposition of radioactive material for brachytherapy devices

Abstract

A method and apparatus for precisely applying radioactive material to a substrate such as a brachytherapy device is disclosed. A radioactive fluid adapted to cure rapidly is deposited as discrete dots onto a surface with a fluid-jet printhead. The apparatus comprises a fluid-jet printhead in communication with a chamber containing radioactive fluid to be applied by the printhead. The printhead is microprocessor driven, and the microprocessor may be provided with feedback from a station where the radioactivity deposited on a preceding substrate in a batch is measured, permitting the system to be recalibrated on an ongoing basis as the batch of printed devices is produced. Compensation for attenuation of radiation by a casing may also be made part of the feedback technique. Also disclosed is a brachytherapy device having printed on a surface dots of radiation-emitting material, in a pattern comprising various bands, dots or areas. Fluids suitable for printing by a fluid-jet printhead comprise a binder such as an acrylic resin or silicate, and a radioactive salt, compound or complex, dissolved in a radiation resistant solvent. Alternative fluids comprise radioactive salts, compounds, or complexes adsorbed onto a microparticulate carrier, or elemental microparticles, dispersed in a rapidly curable radiation-resistant fluid medium.