Recent Developments with Large-Bore PET/CT

Model name

Company

Patient port size [mm]

PET detector ring

FDA cleared

PET

Diameter [mm]

[year]

ECAT Accel

CTI (Siemens)

562

N/A

824

2000

Discovery LS

GE Healthcare

600

700

927

2001

Biograph Duo

Siemens Healthcare

700

824

2002

Discovery ST

GE Healthcare

700

886

2003

Aquiduo

Toshiba Medical Systems

700

720

830

2005^a

GEMINI TF Big Bore

Philips Healthcare

850

900

2009

Biograph TruePoint 16

Siemens Healthcare

700

842

2009

Ingenuity TF

Philips Healthcare

700

900

2011

TruFlight Select

Philips Healthcare

700

2011

Discovery PET/CT 600

GE Healthcare

700

810

Discovery PET/CT 610

GE Healthcare

700

886

2012

Discovery PET/CT 690

GE Healthcare

700

886

Discovery PET/CT 710

GE Healthcare

700

886

2012

Biograph mCT

Siemens Healthcare

780

842

2012

Celesteion

Toshiba Medical Systems

880

900

907

2014

Data were obtained from Imaging Technology News Online and Journal of Nuclear Medicine

^aJapanese FDA only

Fig. 10.1

The subject, who weighed 100 kg and was 176 cm tall, was larger than the average of Japanese male. However, there was plenty of space inside the gantry of the Celesteion to accommodate him

10.2 The Celesteion

The Celesteion PET/CT scanner combines a high-speed helical 16-slice CT scanner with a newly designed PET scanner, which harbors a lutetium–yttrium oxyorthosilicate (LYSO) scintillator block detector. The CT scanner has 16 rows of tube detectors with 994 detector cells per row, and each revolution of a detector can cover up to 32 mm. The scintillator block detector system of the PET scanner contains LYSO crystals arranged in 48 rings. The crystals have a transaxial length of 4 mm and an axial length of 4 mm, which are arranged in detection units (blocks) consisting of 48 × 16 crystals coupled to a photomultiplier. The 48-ring system can obtain 95 PET images (48 direct and 47 cross plane), separated by 2 mm and covering an axial FOV of 19.6 cm. The PET scanner can acquire data in three-dimensional (3D) configurations. The energy window of the system is set to 425–650 keV, and the coincidence time window is set to 1.6–4.2 ns, depending on the size of the FOV. The temporal resolution of the TOF is <450 ps.

10.2.1 Spatial Resolution

The National Electrical Manufacturers Association (NEMA) NU 2 2012 protocol [2] recommends using an F-18 fluorodeoxyglucose (FDG) point source (size <1×1 ×1 mm) inside a 75-mm-long glass capillary tube with an inner diameter of 0.9–1.0 mm and a 0.4-mm-thick wall. The total activity should be low enough to keep dead-time losses and randomness below 5% of the total events. Data were acquired at three transaxial locations (x,y), i.e., (1,0, 10,0, 20,0) cm, and at two axial positions (z) within the PET FOV, i.e., center FOV. At least 2×10⁶ coincidence events were acquired at each position. TOF information was not used in this measurement. No attenuation and scatter correction and no post-smoothing filter were applied. The transverse and axial resolutions at the different positions of the point source are summarized in Table 10.2, which lists the full width at half-maximum (FWHM) values at 1, 10, and 20 cm. These data are provided by Toshiba Medical Systems.

Table 10.2

Spatial resolution measured for the PET component of the Celesteion system (NEMA NU2-2012)

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