Improving PET spatial resolution and detectability for prostate cancer imaging

Abstract

Prostate cancer, one of the most common forms of cancer among men, can benefit from recent improvements in positron emission tomography (PET) technology. In particular, better spatial resolution, lower noise and higher detectability of small lesions could be greatly beneficial for early diagnosis and could provide a strong support for guiding biopsy and surgery. In this article, the impact of improved PET instrumentation with superior spatial resolution and high sensitivity are discussed, together with the latest development in PET technology: resolution recovery and time-of-flight reconstruction. Using simulated cancer lesions, inserted in clinical PET images obtained with conventional protocols, we show that visual identification of the lesions and detectability via numerical observers can already be improved using state of the art PET reconstruction methods. This was achieved using both resolution recovery and time-of-flight reconstruction, and a high resolution image with 2 mm pixel size. Channelized Hotelling numerical observers showed an increase in the area under the LROC curve from 0.52 to 0.58. In addition, a relationship between the simulated input activity and the area under the LROC curve showed that the minimum detectable activity was reduced by more than 23%.

Investigating the limits of PET/CT imaging at very low true count rates and high random fractions in ion‐beam therapy monitoring

“…During projection, the inverse of the mCT normalization and the inverse of the attenuation, as described by the corresponding AC CT of the experimental study, have been applied. 26 Based on the attenuation map and the simulated sinogram, TOF scatter sinograms have been generated by the same single scatter simulation used during image reconstruction 22,27 and added (or not) to the simulated sinograms. The resulting sinogram has been scaled to a given number of "net true" counts (trues + scatter).…”

On the assessment of spatial resolution of PET systems with iterative image reconstruction

“…Spatial resolution of PET is an important parameter which has to be accurately measured to achieve the clinical performance in oncology, such as lesion detection (Bal et al 2014, Polycarpou et al 2014), tumor delineation (Cheebsumon et al 2011, Hofheinz et al 2013) and therapy monitoring (Martí-Climent et al 2014), neurology (Aguiar et al 2008, Mourik et al 2010, Bowen et al 2013), and cardiology (Mohy-Ud-Din et al 2015). Hence when the performance of a PET system is evaluated, measuring the spatial resolution is an important task (Bao et al 2009, Visser et al 2009, Constantinescu and Mukherjee 2009, Popota et al 2012).…”

Imaging of Hsp70-positive tumors with cmHsp70.1 antibody-conjugated gold nanoparticles

“…However, with improved settings, spatial resolutions of 2 mm are technically feasible, as demonstrated in patients with prostate cancer. 2 CT imaging either alone or in combination with PET could be further improved by using metal-based nanoparticles. 3 For application in humans, it is essential that the material of the nanoparticles is nontoxic, transportable in the blood and lymph system, biodegradable, and has a short half-life.…”