Composite skull pins with reduced x-ray signature

Abstract

A composite skull pin comprising: a core comprising a cone terminating in a distal point, the core being formed out of a substantially radiotranslucent material; and a jacket comprising a hollow cone terminating in a sharp distal point, the hollow cone of the jacket being sized and shaped so that it overlies, and closely conforms to, the exterior of the cone of the core, the jacket being formed out of a strong, hard material, and further wherein the jacket has a sufficiently small mass such that the composite skull pin has a low X-ray signature.

What is claimed is: 
     
         1 . A composite skull pin comprising:
 a core comprising a cone terminating in a distal point, the core being formed out of a substantially radiotranslucent material; and   a jacket comprising a hollow cone terminating in a sharp distal point, the hollow cone of the jacket being sized and shaped so that it overlies, and closely conforms to, the exterior of the cone of the core, the jacket being formed out of a strong, hard material, and further wherein the jacket has a sufficiently small mass such that the composite skull pin has a low X-ray signature.   
     
     
         2 . A composite skull pin according to  claim 1  wherein the core is formed out of carbon graphite. 
     
     
         3 . A composite skull pin according to  claim 1  wherein the jacket is formed out of a non-radiotranslucent material. 
     
     
         4 . A composite skull pin according to  claim 1  wherein the jacket is formed out of titanium. 
     
     
         5 . A composite skull pin according to  claim 1  wherein the jacket is formed out of a synthetic plastic material of the type marketed by Integra LifeSciences Corporation of Plainsboro, N.J. under the trade name Sapphire™. 
     
     
         6 . A composite skull pin according to  claim 1  wherein the jacket has a thickness of about 0.010 inches or less. 
     
     
         7 . A composite skull pin according to  claim 1  wherein the core comprises a cylindrical body having the cone on its distal end and a cylinder on its proximal end, with a first annular shoulder being formed at the intersection of cylindrical body and the cone, and a second annular shoulder being formed at the intersection of cylindrical body and the cylinder. 
     
     
         8 . A composite skull pin according to  claim 7  wherein the base of the jacket engages the first annular shoulder of the core. 
     
     
         9 . A composite skull pin according to  claim 7  wherein the core comprises a cylindrical body, wherein the core is mounted to the core by a cylinder, and further wherein the base of the jacket engages portions of the cylinder. 
     
     
         10 . A method for scanning the head of a patient, comprising:
 providing a head frame which is at least partially radiotranslucent, and providing a composite skull pin, where the composite skull pin comprises:
 a core comprising a cone terminating in a distal point, the core being formed out of a substantially radiotranslucent material; and 
 a jacket comprising a hollow cone terminating in a sharp distal point, the hollow cone of the jacket being sized and shaped so that it overlies, and closely conforms to, the exterior of the cone of the core, the jacket being formed out of a strong, hard material, and further wherein the jacket has a sufficiently small mass such that the composite skull pin has a low X-ray signature; and 
   securing the head of a patient to the head frame using the composite skull pin.   
     
     
         11 . A method according to  claim 10  wherein the core is formed out of carbon graphite. 
     
     
         12 . A method according to  claim 10  wherein the jacket is formed out of a non-radiotranslucent material. 
     
     
         13 . A method according to  claim 10  wherein the jacket is formed out of titanium. 
     
     
         14 . A method according to  claim 10  wherein the jacket is formed out of a synthetic plastic material of the type marketed by Integra LifeSciences Corporation of Plainsboro, N.J. under the trade name Sapphire™. 
     
     
         15 . A method according to  claim 10  wherein the jacket has a thickness of about 0.010 inches or less. 
     
     
         16 . A method according to  claim 10  wherein the core comprises a cylindrical body having the cone on its distal end and a cylinder on its proximal end, with a first annular shoulder being formed at the intersection of cylindrical body and the cone, and a second annular shoulder being formed at the intersection of cylindrical body and the cylinder. 
     
     
         17 . A method according to  claim 16  wherein the base of the jacket engages the first annular shoulder of the core. 
     
     
         18 . A method according to  claim 16  wherein the core comprises a cylindrical body, wherein the core is mounted to the core by a cylinder, and further wherein the base of the jacket engages portions of the cylinder.