Neutron Source for Neutron Capture Therapy

Abstract

A therapy apparatus for producing thermal neutrons at a tumor site in a patient has a plurality of fast neutron sources surrounding a moderator, a fast neutron reflecting media around the fast neutron sources, a gamma-ray and neutron shielding media surrounding the fast neutron reflecting media, and a patient chamber positioned inside the moderator. The fast neutron sources are positioned around the moderator to maximize and direct the neutron flux to said tumor site.

1 . A therapy apparatus for producing thermal neutrons at a tumor site in a patient comprising:
 a plurality of fast neutron sources surrounding a moderator;   a fast neutron reflecting media around the fast neutron sources;   a gamma-ray and neutron shielding media surrounding the fast neutron reflecting media; and   a patient chamber positioned inside the moderator;   wherein the fast neutron sources are positioned around the moderator to maximize and direct the neutron flux to said tumor site.   
     
     
         2 . The therapy apparatus according to  claim 1  wherein the moderator maximizes the neutron flux, delivers a uniform dose and a high and uniform therapeutic ratio across the cancer site. 
     
     
         3 . The therapy apparatus according to  claim 1  wherein the patient chamber's position and material of the moderator are selected to produce the maximum, uniform thermal neutron flux and uniform therapeutic ratio at the said tumor sites. 
     
     
         4 . The therapy apparatus according to  claim 1  wherein the fast neutron sources are positioned at a fixed radius and equally spaced in a circle around the moderator. 
     
     
         5 . The therapy apparatus according to  claim 1  wherein the fast neutron sources are moveable and positioned to maximize the neutron flux at the cancer site. 
     
     
         6 . The therapy apparatus according to  claim 1  wherein said fast neutron sources are moveable and are positioned to maximize the neutron flux at the cancer site, to deliver a uniform dose across the cancer site greater than 1 Gy per session with a 10% or less variation, and to deliver a therapeutic ratio at the cancer site greater than 2, and with a uniformity across the cancer site of 10% or less variation. 
     
     
         7 . A therapy apparatus according to  claim 1  wherein said moderator is cylindrical in shape. 
     
     
         8 . A therapy apparatus according to  claim 1  wherein the moderator is hemispherical in shape. 
     
     
         9 . The therapy apparatus according to  claim 1  wherein the moderator is ellipsoidal in shape. 
     
     
         10 . A therapy apparatus for producing thermal neutrons at tumor sites in a patient comprising:
 a plurality of fast neutron sources;   a moderator disposed inside the fast neutron sources;   a patient chamber disposed inside and center of the moderator; and,   a neutron reflector and shielding apparatus disposed around the fast neutron generating target.   
     
     
         11 . A therapy apparatus for producing thermal neutrons at a tumor site in a patient comprising:
 a plurality of ion sources;   a cylindrical electron shield disposed coaxially inside the said ion sources;   a cylindrical fast-neutron generating target disposed coaxially inside said electron shield that includes an ion entrance aperture disposed to have ions emitted from the ion source impact a fast-neutron-generating target;   a cylindrical moderator disposed coaxially inside the said cylindrical fast-neutron-generating target;   a patient chamber disposed coaxially inside said cylindrical moderator; and   a neutron reflection and shielding means disposed coaxially around said ion beam sources.