18F, 11C and 68Ga in small animal PET imaging

J. Muellauer; R. Willimayer; A. L. Goertzen; T. Wanek; O. Langer; W. Birkfellner; C. Kuntner

doi:10.3413/Nukmed-0578-13-04

Nuklearmedizin - NuclearMedicine, Table of Contents

Nuklearmedizin 2013; 52(06): 250-261
DOI: 10.3413/Nukmed-0578-13-04

Original article

Schattauer GmbH

¹⁸F, ¹¹C and ⁶⁸Ga in small animal PET imaging

Evaluation of partial volume correction methods ¹⁸F, ¹¹C und ⁶⁸Ga in der präklinischen BildgebungEvaluierung von Partialvolumeneffekt- Korrekturmethoden

J. Muellauer

¹Biomedical Systems, Health & Environment Department, AIT Austrian Institute of Technology GmbH, Seibersdorf, Austria

,

R. Willimayer

²Nuclear Engineering Seibersdorf GmbH, Seibersdorf, Austria

,

A. L. Goertzen

³Department of Radiology, University of Manitoba, Winnipeg, Canada

,

T. Wanek

¹Biomedical Systems, Health & Environment Department, AIT Austrian Institute of Technology GmbH, Seibersdorf, Austria

,

O. Langer

¹Biomedical Systems, Health & Environment Department, AIT Austrian Institute of Technology GmbH, Seibersdorf, Austria

⁴Department of Clinical Pharmacology, Medical University Vienna, Austria

,

W. Birkfellner

⁵Center for Medical Physics and Biomedical Engineering, Medical University Vienna, Austria

,

C. Kuntner

¹Biomedical Systems, Health & Environment Department, AIT Austrian Institute of Technology GmbH, Seibersdorf, Austria

› Author Affiliations

Abstract

Summary

Aim: The partial volume effect (PVE) significantly affects quantitative accuracy in PET. In this study we used a micro-hollow sphere phantom filled with ¹⁸F, ¹¹C or ⁶⁸Ga to evaluate different partial volume correction methods (PVC). Additionally, phantom data were applied on rat brain scans to evaluate PVC methods on in vivo datasets. Methods: The four spheres (7.81, 6.17, 5.02, 3.90 mm inner diameter) and the background region were filled to give sphere-to-background (sph/bg) activity ratios of 20 : 1, 10 : 1, 5 : 1 and 2 : 1. Two different acquisition and reconstruction protocols and three radionuclides were evaluated using a small animal PET scanner. From the obtained images the recovery coefficients (RC) and contrast recovery coefficients (CRC) for the different sph/bg ratios were calculated. Three methods for PVC were evaluated: a RC based, a CRC based and a volume of interest (VOI) based method. The most suitable PVC methods were applied to in vivo rat brain data. Results: RCs were shown to be dependent on the radionuclide used, with the highest values for ¹⁸F, followed by ¹¹C and ⁶⁸Ga. The calculated mean CRCs were generally lower than the corresponding mean RCs. Application of the different PVC methods to rat brain data led to a strong increase in time-activity curves for the smallest brain region (entorhinal cortex), whereas the lowest increase was obtained for the largest brain region (cerebellum). Conclusion: This study was able to show the importance and impact of PVE and the limitations of several PVC methods when performing quantitative measurements in small structures.

Zusammenfassung

Ziel: Der Partialvolumeneffekt (PVE) beeinflusst die quantitative Genauigkeit bei der PET. In dieser Studie wurde ein Phantom mit kleinen Kugeln verwendet, die mit ¹⁸F, ¹¹C oder ⁶⁸Ga gefüllt wurden um verschiedene PVE-Korrekturmethoden zu testen. Danach wurden die ermittelten Faktoren auf einen In-vivo-Datensatz basierend auf Rattenhirn-Scans angewendet. Methoden: Die vier kleinen Kugeln (Innendurchmesser: 7.81, 6.17, 5.02, 3.90 mm) und die Hintergrundregion wurden mit verschiedenen Aktivitätskonzentrationen gefüllt um folgende Ratios zwischen Kugeln und Hintergrund zu erhalten: 20 : 1, 10 : 1, 5 : 1 und 2 : 1. Zwei Akquisitions- und Rekonstruktionsprotokolle sowie drei Radionuklide wurden mit einem microPET-Scanner gemessen. Die Recovery-Koeffizienten (RC) und Kontrast-Recovery-Koeffizienten (CRC) wurden an Hand der Bilder berechnet. Drei Korrekturmethoden wurden getestet: eine Methode basierend auf dem RC, eine basierend auf dem CRC und eine basierend auf dem Volumen von Interesse (VOI). Danach wurden die Methoden auf den In-vivo-Datensatz angewendet. Ergebnisse: Die RCs zeigten eine starke Abhängigkeit vom Radionuklid mit den höchsten Werten für ¹⁸F, gefolgt von ¹¹C und ⁶⁸Ga. Die berechneten CRCs waren im Allgemeinen niedriger als die entsprechenden RCs. Die Anwendung der verschiedenen Korrekturmethoden auf den Rattenhirn Scan führte zu einem starken Anstieg in den Zeit- Aktivitätskurven von kleinen Hirnregionen (entorhinaler Kortex), während für größere Hirnregionen (Zerebellum) nur kleine Anstiege erhalten wurden. Schlussfolgerung: Diese Studie zeigt die Wichtigkeit und Auswirkung vom PVE sowie die Einschränkungen diverser PVE-Korrekturen bei der quantitativen Auswertung kleiner Strukturen in der präklinischen Bildgebung.

Keywords

Positron emission tomography - PET - quantification - partial volume effect - partial volume correction - recovery coefficient

Schlüsselwörter

Positronenemissionstomographie - PET - Quantifizierung - Partialvolumeneffekt

Full Text

References

References
1 Bazañez-Borgert M, Bundschuh RA, Herz M. et al. Radioactive spheres without inactive wall for lesion simulation in PET. Zeitschrift für Medizinische Physik 2008; 18: 37-42.
2 Beyer T, Kinahan PE, Townsend DW. Optimization of transmission and emission scan duration in 3D whole-body PET. Ieee T Nucl Sci 1997; 44: 2400-2407.
3 Boellaard R, Krak NC, Hoekstra OS, Lammertsma AA. Effects of noise, image resolution, and ROI definition on the accuracy of standard uptake values: a simulation study. J Nucl Med 2004; 45: 1519-1527.
4 Chatziioannou A, Qi J, Moore A. et al. Comparison of 3-D maximum a posteriori and filtered backprojection algorithms for high-resolution animal imaging with microPET. IEEE Trans Med Imaging 2000; 19: 507-512.
5 Chen CH, Muzic Jr RF, Nelson AD, Adler LP. Simultaneous recovery of size and radioactivity concentration of small spheroids with PET data. J Nucl Med 1999; 40: 118-130.
6 Cherry SR, Sorenson JA, Phelps ME. Physics in nuclear medicine. Philadelphia, Pa.; [London]: W. B. Saunders; 2003: xiii 523.
7 De Jong HWAM, Perk L, Visser GWM. et al. (eds). High resolution PET imaging characteristics of /sup 68/Ga, /sup 124/I and /sup 89/Zr compared to /sup 18/F. Nuclear Science Symposium Conference Record, 2005 IEEE; 2005 23–29 Oct. 2005
8 Disselhorst JA, Brom M, Laverman P. et al. Imagequality assessment for several positron emitters using the NEMA NU 4–2008 standards in the Siemens Inveon small-animal PET scanner. J Nucl Med 2010; 51: 610-617.
9 Geworski L, Knoop BO, de Cabrejas ML. et al. Recovery correction for quantitation in emission tomography: a feasibility study. Eur J Nucl Med 2000; 27: 161-169.
10 Glien M, Brandt C, Potschka H. et al. Repeated low-dose treatment of rats with pilocarpine: low mortality but high proportion of rats developing epilepsy. Epilepsy Res 2001; 46: 111-119.
11 Hoffman EJ, Huang SC, Phelps ME. Quantitation in positron emission computed tomography: 1. Effect of object size. J Comput Assist Tomogr 1979; 3: 299-308.
12 Holm S, Toft P, Jensen M. Estimation of the noisecontributions from blank, transmission and emission scans in PET. IEEE T Nucl Sci 1996; 43: 2285-2291.
13 Kessler RM, Ellis Jr JR, Eden M. Analysis of emission tomographic scan data: limitations imposed by resolution and background. J Comput Assist Tomogr 1984; 8: 514-522.
14 Kuntner C, Bankstahl JP, Bankstahl M. et al. Doseresponse assessment of tariquidar and elacridar and regional quantification of P-glycoprotein inhibition at the rat blood-brain barrier using (R)-[¹¹C]verapamil PET. Eur J Nucl Med Mol Imaging 2010; 37: 942-953.
15 Lehnert W, Gregoire MC, Reilhac A, Meikle SR. Characterisation of partial volume effect and region- based correction in small animal positron emission tomography (PET) of the rat brain. Neuroimage 2012; 60: 2144-2157.
16 Levin CS, Hoffman EJ. Calculation of positron range and its effect on the fundamental limit of positron emission tomography system spatial resolution. Physics in Medicine and Biology 1999; 44: 781-799.
17 NEMA Standards Publication NU 2–2007: Performance Measurement of Positron Emission Tomographs. Washington, DC: NEMA; 2007
18 Prieto E, Marti-Climent JM, Arbizu J. et al. Evaluation of spatial resolution of a PET scanner through the simulation and experimental measurement of the recovery coefficient. Comput Biol Med 2010; 40: 75-80.
19 Phelps ME, Hoffman EJ, Huang SC, Ter-Pogossian MM. Effect of positron range on spatial resolution. J Nucl Med 1975; 16: 649-652.
20 Phelps ME. PET: Molecular Imaging and Its Biological Applications. Phelps ME. (ed). Berlin: Springer; 2004
21 Qi J, Leahy RM, Cherry SR. et al. High-resolution 3D Bayesian image reconstruction using the microPET small-animal scanner. Physics in Medicine and Biology 1998; 43: 1001-1013.
22 Rousset OG, Collins DL, Rahmim A, Wong DF. Design and implementation of an automated partial volume correction in PET: application to dopamine receptor quantification in the normal human striatum. J Nucl Med 2008; 49: 1097-1106.
23 Rousset OG, Ma Y, Evans AC. Correction for partial volume effects in PET: principle and validation. J Nucl Med 1998; 39: 904-911.
24 Rousset O, Rahmim A, Alavi A, Zaidi H. Partial Volume Correction Strategies in PET. PET Clinics 2007; 2: 235-249.
25 Soret M, Bacharach SL, Buvat I. Partial-volume effect in PET tumor imaging. J Nucl Med 2007; 48: 932-945.
26 Srinivas SM, Dhurairaj T, Basu S. et al. A recovery coefficient method for partial volume correction of PET images. Ann Nucl Med 2009; 23: 341-348.
27 Strother SC, Casey ME, Hoffman EJ. Measuring Pet Scanner Sensitivity – Relating Countrates to Image Signal-to-Noise Ratios Using Noise Equivalent Counts. IEEE T Nucl Sci 1990; 37: 783-788.
28 Tai YC, Ruangma A, Rowland D. et al. Performance evaluation of the microPET focus: a thirdgeneration microPET scanner dedicated to animal imaging. J Nucl Med 2005; 46: 455-463.
29 Valk PE. Positron emission tomography: clinical practice. London: Springer; 2006
30 Vanderhoek M, Perlman SB, Jeraj R. Impact of the definition of peak standardized uptake value on quantification of treatment response. J Nucl Med 2012; 53: 4-11.
31 Wienhard K, Schmand M, Casey ME. et al. The ECAT HRRT: performance and first clinical application of the new high resolution research tomograph. Nuclear Science, IEEE Transactions on 2002; 49: 104-110.
32 Zaidi H. Correction for image degrading factors is essential for accurate quantification of brain function using PET. For the proposition. Med Phys 2004; 31: 423-425.