Low energy electron beam radiation system that generates electron beams with precisely controlled and adjustable penetration depth useful for therapeutic applications

An electron beam radiation system useful to irradiate a target site on a patient with an electron beam radiation dose having a controlled and adjustable penetration depth, said system comprising:

• a) a power source providing a power output;
• b) a microwave source that receives the power output from the power source and emits microwave energy;
• c) a microwave network that receives the microwave energy from the microwave source;
• d) an electron beam source that emits an electron beam;
• e) an accelerator system configured to receive the electron beam from the electron beam source and to receive the microwave energy from the microwave network in a manner effective to accelerate the electron beam toward the target site;
• f) a collimator that receives and shapes the accelerated electron beam;
• and
• g) a feedback control system, comprising:
• 1) a first electron beam sensor that measures a first characteristic of the accelerated electron beam;
• 2) a second beam sensor that measures a second characteristic of the accelerated electron beam that is different from the first characteristic;
• and wherein:
• the feedback control system uses first and second signals from the first and second sensors to derive an analog characteristic of electron beam energy;
• and
• the feedback control system uses the analog of electron beam energy to generate a control signal that controls the electron beam energy at a level that is in the range from 0.1 MeV to 6 MeV and that corresponds to a desired penetration depth at the target site.

An electron beam radiation system useful to irradiate a target site with electron beam radiation dose having an adjustable penetration depth, said system comprising:

• a. an electron beam directed at the target site, said electron beam having an adjustable and controllable electron beam energy adjusted to correspond to a desired penetration depth;
• and
• b. a library of electron beam absorbers configured to provide stepwise tuning of an electron beam in increments of 2 mm or less, wherein at least one electron beam absorber is presented to the electron beam in a manner to reduce the electron beam energy to control the penetration depth of the electron beam dose delivered to the target;
• and
• c. a feedback system configured to stabilize the penetration depth of a linearly accelerated, straight through electron beam having an electron beam energy, said system providing a control signal derived from a plurality of sensed electron beam characteristics that in combination correlate to the electron beam energy.

A method for irradiating a target site on a patient with an electron beam radiation dose having a controlled and adjusted penetration depth, comprising the steps of:

• a) aiming an electron beam at the target site on the patient, wherein the electron beam has an adjustable and controllable electron beam energy adjusted to correspond to a desired penetration depth;
• and
• b) using a control system to adjust the electron beam to an energy effective to correspond to the desired penetration depth;
• c) using the control system to monitor the electron beam and to use at least first and second sensed characteristics to derive an analog of electron beam energy;
• d) using the control system to derive an error signal from information comprising the analog characteristic of the electron beam energy and a reference value;
• and
• e) using the control system to generate a control signal that controls the electron beam.