Abstract: Provided is a positron emission tomography (PET) detector module using Geiger-mode avalanche photodiode (GAPD) as a photosensor. The PET detector module includes: a PET detector unit with a scintillation crystal detecting gamma rays emitted from a living body and converting them into a scintillation light and a first GAPD photosensor and a second GAPD photosensor each being connected to either end of the scintillation crystal and converting the scintillation light into an electrical signal; and a depth of interaction (DOI) decoding unit receiving the signals from the PET detector unit and comparing amplitude of the signals detected by the first GAPD photosensor and the second GAPD photosensor, thereby providing the depth information where the gamma rays are incident on the scintillation crystal (DOI). The disclosed PET detector module can provide improved energy resolution and additional DOI information while maintaining linearity.

Abstract: Provided is a method for removing noise of a positron emission tomography (PET) signal in a PET-magnetic resonance imaging (MRI) fusion device without using an MRI radio frequency (RF) shield that degrades image quality. The method includes: (a1) converting a PET analog signal into a digital signal having a predetermined sampling frequency; (b1) determining whether the resulting PET digital signal is to be included in image reconstruction based on modeling using sampling points of the PET digital signal or an integration value of the PET digital signal; and (c1) extracting only the PET digital signal that will be included in image reconstruction. The method allows acquisition of molecular-level images without declined performance of a PET detector.

Abstract: Provided is a method for removing noise of a positron emission tomography (PET) signal in a PET-magnetic resonance imaging (MRI) fusion device without using an MRI radio frequency (RF) shield that degrades image quality. The method includes: receiving a PET output signal from a PET-MRI fusion device and performing analog filtering by removing noise components due to an RF pulse frequency based on the relationship between the frequency of the PET output signal and a magnetic resonance (MR) RF frequency (Larmor frequency); and converting the filtered signal into a digital signal through sampling. The method allows acquisition of molecular-level images without declined performance of a PET detector in MRI environment.

Abstract: Provided is a positron emission tomography (PET) detector module using Geiger-mode avalanche photodiode (GAPD) as a photosensor. The PET detector module includes: a PET detector unit comprising a scintillation crystal detecting gamma rays emitted from a living body and converting them into a flash of light and a first GAPD photosensor and a second GAPD photosensor each being connected to either end of the scintillation crystal and converting the light flash into an electrical signal; and a reaction depth determination unit receiving the signals from the PET detector unit and comparing amplitude of the signals detected by the first GAPD photosensor and the second GAPD photosensor, thereby determining the position where the gamma rays are incident on the scintillation crystal (reaction depth). The disclosed PET detector module can provide high energy and high energy and reaction depth data while maintaining linearity.