Patent Number: 
Section: abstract

The present invention provides a catheter having an x-ray generator unit at its tip which generates x-ray radiation having a wavelength in a range effective for treating biological tissue. In one embodiment, the x-ray generator unit includes a miniature x-ray generator and a miniature transformer that form, in combination, a monolithic device. The transformer includes a primary winding that receives an input voltage in a range of 100 V to 4 kV from a power source, via a flexible cable that runs from the proximal end of the catheter body to its distal end. The transformer further includes a secondary winding that up-converts the input voltage to generate an output voltage in a range of 10 kV to 40 kV to be applied to a cathode of the x-ray generator. The cathode emits electrons in response to the applied voltage, and an extraction electrode guides the emitted electrons to an anode, which is preferably formed of a high-Z refractory metal. The impact of the electrons with the anode effects generation of x-ray radiation, a portion of which is transmitted via an x-ray transmissive window to the outside environment. One significant advantage of the device of the invention is that by employing a lower voltage in the body of the catheter and confining a higher voltage to a short, rigid section at the distal end of the catheter, the device provides enhanced mechanical flexibility and lowers the likelihood of electrical breakdown.