PET-MRI apparatus

Patent metadata

Field	Value
Publication number	US-9864028-B2
Application number	US-201313873706-A
Country	US
Kind code	B2
Filing date	Apr 30, 2013
Priority date	Nov 1, 2010
Publication date	Jan 9, 2018
Grant date	Jan 9, 2018

Abstract

In a PET (Positron Emission Tomography)-MRI (Magnetic Resonance Imaging) apparatus of an embodiment, a transmitting radio frequency coil applies a radio frequency magnetic field on a subject placed in a static magnetic field. A detector is formed in a ring shape, disposed on a side adjacent to an outer circumference of the transmitting radio frequency coil, includes at least two PET detectors disposed with a space therebetween in an axial direction of a bore so as to interpose the magnetic field center of the static magnetic field therebetween, and detects gamma rays emitted from positron emitting radionuclides injected into the subject. Radio frequency shields are each formed in an approximately cylindrical shape, disposed between the transmitting radio frequency coil and the detector, and shield the radio frequency magnetic field generated by the transmitting radio frequency coil.

First claim

What is claimed is:

1. A PET (Positron Emission Tomography)-MRI (Magnetic Resonance Imaging) apparatus, comprising:
a magnet configured to generate a static magnetic field in a bore having an approximately cylindrical shape;
a transmitting radio frequency coil configured to apply a radio frequency magnetic field on a subject placed in the static magnetic field;
a gradient coil configured to apply a gradient magnetic field on the subject;
a receiving radio frequency coil configured to detect a magnetic resonance signal emitted from the subject due to application of the radio frequency magnetic field and the gradient magnetic field on the subject;
an MR image reconstruction unit configured to reconstruct an MR image based on the magnetic resonance signal detected by the receiving radio frequency coil;
a detector configured to be formed in a ring shape, disposed on a side adjacent to an outer circumference of the transmitting radio frequency coil, include at least two PET detectors disposed with a space therebetween in an axial direction of the bore so as to interpose a magnetic field center of the static magnetic field therebetween, and detect gamma rays emitted from a positron emitting radionuclide injected into the subject;
a PET image reconstruction unit configured to reconstruct a PET image from projection data produced based on the gamma rays detected by the detector; and
a radio frequency shield configured to have an approximately cylindrical shape, be disposed between the transmitting radio frequency coil and the detector, and shield a radio frequency magnetic field generated by the transmitting radio frequency coil.

2. The PET-MRI apparatus according to claim 1 , wherein the radio frequency shield is disposed on a side adjacent to an inner circumference of the detector.

3. The PET-MRI apparatus according to claim 2 , wherein a signal line connected to the detector is routed on a side adjacent to an outer circumference of the radio frequency shield.

4. The PET-MRI apparatus according to claim 1 , further comprising:
a first radio frequency shield configured to have an approximately cylindrical shape and be disposed on a side adjacent to an outer circumference of the detector; and
a second radio frequency shield configured to be formed so as to cover an exposed surface of the detector.

5. The PET-MM apparatus according to claim 4 , wherein a signal line connected to the detector is routed on a side adjacent to an outer circumference of the first radio frequency shield.

6. The PET-MRI apparatus according to claim 4 , wherein the signal line connected to the detector is routed on a side adjacent to an inner circumference of the first radio frequency shield, and
the signal line is a coaxial cable and an outer conductor of the coaxial cable is electrically connected to the first radio frequency shield.

7. The PET-MRI apparatus according to claim 4 , wherein the signal line connected to the detector is routed on a side adjacent to an inner circumference of the first radio frequency shield, and
the signal line is covered with a third radio frequency shield.

Assignees

• Nat Institute Of Radiological Sciences
• Toshiba Medical Sys Corp
• National Institutes For Quantum And Radiological Science And Tech

Inventors

• Kanno Iwao
• Obata Takayuki
• Yamaya Taiga
• Okamoto Kazuya
• Takayama Takuzo
• Yamagata Hitoshi

Classifications

• G01T1/1603

  with a combination of at least two different types of detectors · CPC title

• G01R33/481

  MR combined with positron emission tomography [PET] or single photon emission computed tomography [SPECT] · CPC title

• A61B6/5247

  combining images from an ionising-radiation diagnostic technique and a non-ionising radiation diagnostic technique, e.g. X-ray and ultrasound · CPC title

• A61B6/5235

  combining images from the same or different ionising radiation imaging techniques, e.g. PET and CT · CPC title

• A61B6/4417

  related to combined acquisition of different diagnostic modalities · CPC title