Fundamental limits of spatial resolution in PET

Abstract

The fundamental limits of spatial resolution in positron emission tomography (PET) have been understood for many years. The physical size of the detector element usually plays the dominant role in determining resolution, but the combined contributions from acollinearity, positron range, penetration into the detector ring, and decoding errors in the detector modules often combine to be of similar size. In addition, the sampling geometry and statistical noise further degrade the effective resolution. This paper describes quantitatively describes these effects, discusses potential methods for reducing the magnitude of these effects, and computes the ultimately achievable spatial resolution for clinical and pre-clinical PET cameras.

Future imaging of atherosclerosis: molecular imaging of coronary atherosclerosis with 18F positron emission tomography

“…When combined with PET's fundamental limitation of spatial resolution (4.2-6.3 millimeters) contributed to by detector size, positron emission range, and non-collinearity, the ability for PET to be able to differentiate between coronary artery and myocardium significantly effects its ability to identify true coronary signal (72,73). While efforts have been made to reduce background myocardial uptake, for example by providing a low carbohydrate-high fat diet prior to scan acquisition (74), the rate of uninterpretable scans in human patients remains prohibitively high.…”

Time-of-Flight Positron Emission Tomography with Resistive Plate Chamber Detectors: An Unlikely but Promising Approach

“…These values are about twice as better than those reported for three commercially available state-of-the-art PET scanner with TOF information (the Philips Gemini TF [21], the GE Discovery 690 [22,23], and the Siemens Biograph mCT [24]). The eect of photon acollinearity on the SR was found to be much lower than that generally reported in the literature [25]. This was also shown by reconstructing coincidence data aected by a 0.58…”

“…• FWHM Gaussian distribution in the direction of one photon relative to the direction of the other, obtained mathematically for an ideal unsegmented cylindrical PET scanner with a diameter of 1000 mm and an AFOV of 2400 mm, indicating that the eect of acollinearity in the SR generally assumed in the literature [25] may be overestimated. These results deserve further research, not only by simulation, but also experimentally, by assessing the eect of photon acollinearity in the SR with detectors with higher intrinsic SR, as those currently employed in a pre-clinical RPC PET system.…”

“…Moreover, the eect was found to be strongly dependent on the detector segmentation, but not on the photon acollinearity [8,11]. Moreover, the observed eect was much less than the 0.0022 × D (with D the scanner diameter), generally assumed in the literature [25]. [11].…”

Arterial Input Function Derived from Pairwise Correlations Between PET-image Voxels

“…[1][2][3] Positron emission tomography is associated with limited spatial resolution due to the challenging physical properties of emission tomography. 4 Earlier PET systems normally had an estimated resolution of B6 mm full width at half maximum (FWHM), preventing accurate measurement of radioligand binding in small anatomic structures. 5 However, methodological advancements in acquisition hardware and image reconstruction software have significantly improved the sensitivity and the resolution of more recently developed PET systems.…”