Peripheral tumour treatment

Abstract

A magnetic resonance (MR)-radiotherapy (RT) hybrid system for treating a patient is disclosed. The MR-RT hybrid system comprises: an MR imaging (MRI) apparatus comprising bi-planar magnets configured to generate a magnetic field; a radiation source configured to supply a radiation beam to treat the patient; a gantry configured to couple the MR apparatus at a first end and the radiation source so that they can rotate in unison; a treatment support configured to support the patient; a motor configured to move the treatment support; and a controller. The controller comprises a processor and memory having stored thereon instructions, which when executed by the processor, cause the motor to move the treatment support in order to avoid collision between the MRI apparatus and the patient when the MRI apparatus is rotated. A method for positioning the treatment support within the MR-RT hybrid system is also disclosed.

1 . A magnetic resonance (MR)-radiotherapy (RT) hybrid system for treating a patient, the MR-RT hybrid system comprising:
 an MR imaging (MRI) apparatus comprising bi-planar magnets configured to generate a magnetic field;   a radiation source configured to supply a radiation beam to treat the patient;   a gantry configured to couple the MR apparatus at a first end and the radiation source so that they can rotate in unison;   a treatment support configured to support the patient;   a motor configured to move the treatment support; and   a controller comprising:
 a processor; and 
 memory having stored thereon instructions, which when executed by the processor, cause the motor to move the treatment support in order to avoid collision between the MRI apparatus and the patient when the MRI apparatus is rotated. 
   
     
     
         2 . The MR-RT hybrid system of  claim 1 , wherein the instructions cause the motor to move the patient to a central location prior to rotation of the MRI apparatus is rotated and to a treatment position prior to treatment of the patient. 
     
     
         3 . The MR-RT hybrid system of  claim 2 , wherein the central location is located within the MR-RT hybrid system. 
     
     
         4 . The MR-RT hybrid system of  claim 3 , wherein the central location is an isocentre of the MR-RT hybrid system. 
     
     
         5 . The MR-RT hybrid system of  claim 1 , wherein the radiation beam is focused at an isocentre of the MR-RT hybrid system. 
     
     
         6 . The MR-RT hybrid system of  claim 5 , wherein in the treatment position, a target volume in the patient is aligned with the isocentre along a beam axis of the radiation source. 
     
     
         7 . The MR-RT hybrid system of  claim 1 , wherein the gantry is configured to rotate only when the patient is at the central location. 
     
     
         8 . The MR-RT hybrid system of  claim 1 , wherein the gantry further comprises a support structure connecting the bi-planar magnets distal from the first end, the support structure having an opening larger than a pole to pole spacing of the bi-planar magnets. 
     
     
         9 . A method for positioning a treatment support upon which a patient is positioned within an MR-RT hybrid system, the method comprising:
 positioning the treatment support at a central location defined to avoid collision between the patient and the MR-RT hybrid system;   rotating a gantry of the MR-RT hybrid system to a gantry angle;   moving the treatment support to a treatment position;   applying a treatment beam; and   moving the treatment support to avoid collision between the MR-RT hybrid system and the patient when the gantry is rotated to a different gantry angle.   
     
     
         10 . The method of  claim 9 , wherein the treatment support is moved concurrently with the gantry to avoid collision. 
     
     
         11 . The method of  claim 9 , wherein the treatment support is moved to the central position prior to rotation of the gantry and to the treatment position after rotation of the gantry. 
     
     
         12 . The method of  claim 11 , wherein the central location is located within the MR-RT hybrid system. 
     
     
         13 . The method of  claim 12 , wherein the central location is an isocentre of the MR-RT hybrid system. 
     
     
         14 . The method of  claim 9 , further comprising focusing a radiation beam at an isocentre of the MR-RT hybrid system. 
     
     
         15 . The method of  claim 14 , wherein moving the treatment support to the treatment position aligns a target volume in the patient with the isocentre along a beam axis of the MR-RT hybrid system. 
     
     
         16 . The method of  claim 11 , wherein the gantry is only rotated when the patient is at the central location. 
     
     
         17 . The method of  claim 13 , wherein the treatment support is positioned at the isocentre by aligning a patient centre with the isocentre. 
     
     
         18 . The method of  claim 17 , wherein the patient centre is determined using contour analysis prior to positioning the treatment support at the central location. 
     
     
         19 . The method of  claim 18 , wherein MR imaging is used to confirm that the patient centre is correctly aligned with the isocentre prior to an initial rotation of the gantry. 
     
     
         20 . The method of  claim 19 , wherein the MR imaging comprises:
 i) obtaining an image of the portion of the anatomy of interest at the isocentre;   ii) translating the treatment support so that a different portion of the anatomy of interest is at the isocentre;   iii) repeating i) and ii) until images of the entire anatomy of interest have been obtained; and   iv) stitching the images of the entire anatomy of interest together to obtain the complete image.   
     
     
         21 . A computer readable medium having stored thereon instructions for positioning a treatment support upon which a patient is positioned within an MR-RT hybrid system, the instructions when executed by a processor:
 position the treatment support at a central location defined to avoid collision between the patient and the MR-RT hybrid system;   rotate a gantry of the MR-RT hybrid system to a gantry angle;   move the treatment support to a treatment position;   apply a treatment beam; and   move the treatment support to avoid collision between the MR-RT hybrid system and the patient when the gantry is rotated to a different gantry angle.