Sampled intensity profiles of the reconstructed image shown in Figure 5.

<p>The sample lines in (a) show the locations of the profiles.</p

Phantom images with the dotted rectangles as imaging region-of-interest.

<p>(a) The NEMA-IQ phantom is about cm in size, including four hot lesions (10 mm, 13 mm, 17 mm and 22 mm in diameter) and two cold lesions (28 mm and 37 mm in diameter). The region-of-interest size is cm. (b) The Zubal abdomen phantom is about cm in size. The region-of-interest size is cm.</p

Reconstructed images of NEMA-IQ phantom obtained from TOF-PET data with different timing resolutions.

<p>Note that only the structures inside the ROI are displayed.</p

Sampled intensity profiles for NEMA-IQ phantom obtained from TOF-PET data with different TRs.

<p>The profiles were obtained from the reconstructed images shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0072109#pone-0072109-g007" target="_blank">Figure 7</a>.</p

Contrast recovery coefficients versus iteration number for the TOF-PET data with different timing resolutions.

<p>To avoid misleading impacts introduced by artifacts and distortions on contrast recovery coefficient values, only image results for 100–400 ps full width at half maximum TOF-PET data were analyzed here.</p

Reconstructed images of Zubal abdomen phantom obtained from TOF-PET data with different timing resolutions.

<p>The circle shows the low uptake lesion inside the liver. Note that only the structures inside the ROI are displayed.</p

Event discrimination in data acquisition.

<p> indicates the arrival time difference of two photons, is the speed of light, is the distance between the annihilation position and the midpoint of line-of-response.</p

Measurable time differences distribution in conventional (a) and region-of-interest imaging (b).

<p>The distribution was assumed as a Gaussian function with full width at half maximum determined by the system timing resolution.</p

The three-compartment model describing RGD tracer kinetics in tumor and the two-compartment model describing RGD tracer kinetics in reference tissue.

<p>Cp represents tracer concentration in arterial blood plasma. Ct represents the free or non-specific binding of tracer in interstitial and intracellular space. Cm represents the portion of RGD tracer bound specifically to integrin. K₁, k₂, k₃ and k₄ are the transport and binding rates of the tracer. K1 [ml/g/min] reflects the perfusion rate into tissue. k₂ [1/min] represents the clearance rate from plasma. k₃ [1/min] is the specific binding rate and k₄ [1/min] is the dissociation rate.</p

Tumor time-activity curves derived from 60-min dynamic PET scans of mice after administration of dimeric RGD peptide tracers.

<p>(<b>a</b>) [¹⁸F]AlF-NOTA-PRGD2, (<b>b</b>) [¹⁸F]FPPRGD2, and (<b>c</b>) [⁶⁸Ga]Ga-NOTA-PRGD2 (n = 4/group).</p