Recent Developments in PET Instrumentation

Abstract

Positron emission tomography (PET) is used in the clinic and in vivo small animal research to study molecular processes associated with diseases such as cancer, heart disease, and neurological disorders, and to guide the discovery and development of new treatments. This paper reviews current challenges of advancing PET technology and some of newly developed PET detectors and systems. The paper focuses on four aspects of PET instrumentation: high photon detection sensitivity; improved spatial resolution; depth-of-interaction (DOI) resolution and time-of-flight (TOF). Improved system geometry, novel non-scintillator based detectors, and tapered scintillation crystal arrays are able to enhance the photon detection sensitivity of a PET system. Several challenges for achieving high resolution with standard scintillator-based PET detectors are discussed. Novel detectors with 3-D positioning capability have great potential to be deployed in PET for achieving spatial resolution better than 1 mm, such as cadmium-zinc-telluride (CZT) and position-sensitive avalanche photodiodes (PSAPDs). DOI capability enables a PET system to mitigate parallax error and achieve uniform spatial resolution across the field-of-view (FOV). Six common DOI designs, as well as advantages and limitations of each design, are discussed. The availability of fast scintillation crystals such as LaBr3, and the silicon photomultiplier (SiPM) greatly advances TOF-PET development. Recent instrumentation and initial results of clinical trials are briefly presented. If successful, these technology advances, together with new probe molecules, will substantially enhance the molecular sensitivity of PET and thus increase its role in preclinical and clinical research as well as evaluating and managing disease in the clinic.

Side readout of long scintillation crystal elements with digital SiPM for TOF‐DOI PET

“…1 That is, the following characteristics are desired in PET detectors to produce high quality images: fine spatial resolution (in 3D) to pinpoint the annihilation photon interactions coming from the distribution of radiotracers; a high energy resolution to accurately distinguish true coincidence events from scattered events; excellent timing resolution to reduce random coincidences and for time-of-flight (TOF) PET capabilities; and a high detector photon sensitivity (including small detector deadtime) to effectively stop the 511 keV photons and reduce noise from the counting statistics (high image signal-to-noise ratio).…”

Potential of PET-MRI for imaging of non-oncologic musculoskeletal disease

“…Recent advancements have overcome many technical challenges, including interference between imaging modalities, to make integrated PET-MR systems possible ( Figure 1) (32,33). The main challenges revolve around (36) has made truly simultaneous PET-MRI possible.…”

Review of amorphous silicon based particle detectors: the quest for single particle detection

“…Detection is here limited by the TFT leakage, readout frequency and imager size. Positron emission tomography (PET) scanning [88] is also attracting attention for the application of a-Si:H photodiodes [89]. This medical imaging technique is based on the use of a radioactive positron emitter injected into the patient's blood.…”