Exprerimental Evaluation of a Dedicated Pinhole SPECT System for Small Animal Imaging and Scintimammography

S. David, M. Georgiou, E. Fysikopoulos, G. Loudos


Nuclear medicine (SPECT and PET) provides functional information, which is complementary to the structural. In cancer imaging radiopharmaceuticals allow visualization of cancer cells functionality, thus small cell population can be imaged. This allows early diagnosis, as well as fast assessment of response to therapy. Our system is a single head gamma camera based on an R3292 position sensitive photomultiplier tube (PSPMT), coupled to a 10cm in diameter CsI:Tl crystal. We have assessed two CsI:Tl crystals with pixel size of 2x2mm2 and 3x3mm2 respectively. Three collimators were tested: a) a hexagonal, 1.1mm in diameter, general purpose parallel hole collimator b) a 1mm pinhole and c) a 2mm pinhole. Systems were tested using capillary phantoms. All measurements were carried out in photon counting mode with gamma radiation produced by 99mTc. Using the 2x2mm2 crystal and the 1mm pinhole collimator - a resolution better than 1mm was achieved. This allows very detailed imaging of small animals. Using the 3x3mm2 and the 2mm pinhole collimator a resolution of 1.3mm was possible with suitable sensitivity for breast imaging. Those results indicate that this system is suitable for animal and breast studies. The next step will be clinical evaluation of the camera.


dedicated gamma camera; PSPMT; small animal imaging; scintimammography; pinhole

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R. Pani, M. N. Cinti, R. Pellegrini et al., “Compact large FoV gamma camera for breast molecular imaging”, Nucl. Instr. and Meth. A, Vol. 569, pp. 255–259, 2006

C. B. Hruska, M. K. O’Connor, D. A. Collins, “Comparison of small field of view gamma camera systems for scintimammography”, Nucl. Med. Commun., Vol. 26, pp. 441–445, 2005

S. Vecchio, N. Belcari, P. Bennati, “A single photon emission computer tomograph for breast cancer imaging”, Nucl. Instr. and Meth. A, Vol. 581, pp. 84-87, 2007

R.Wojcik, S. Majewski, D. Steinbach, A.G. Weisenberger, “High Spatial resolution Gamma Imaging Detector Based on 5” Diameter R3292 Hamamatsu PSPMT,” IEEE Trans. Nucl. Sci., Vol. 45, No. 3, pp. 487-491, 1998

D. P. McElroy, L. R. MacDonald, F. J. Beekman, Y. Wang, B. E. Patt, J. S. Iwanczyk, B. M. W. Tsui, E. J. Hoffman, “Performance evaluation of A-SPECT: A high-resolution desktop pinhole SPECT system for imaging small animals,” IEEE Trans. Nucl. Sci., Vol. 49, No. 5, pp. 2139-2147, 2002

R. Pani, R. Pellegrini, M. N. Cinti et al. , “Imaging detector designs based on flat panel PMT”, Nucl. Instr. and Meth. A ,Vol. 527, pp. 54-57, 2004.

Del. Guerra, Ionizing Radiation Detectors for Medical Imaging, (Singapore: World Scientific Publishing, Co. Pte. Ltd.), 2004

W. Moses, V. Gayshan, A. Gektin, "The evolution of SPECT – from Anger to today and beyond", Radiation Detectors for Medical Applications, pp. 37–80, 2006

S. Siegel, R. W. Silverman, Y. Shao, S. R. Cherry, "Simple charge division readouts for imaging scintillator arrays using a multi-channel PMT”, IEEE Trans. Nucl. Sci., Vol. 43, pp. 1634-1641, 1996

V. Popov, S. Majewski, A. G. Weisenberger, R. Wojcik, "Analog readout system with charge division type output” in IEEE NSS, 2001

D.P.McElroy, et al., “Ultra High resolution in vivo I-125 and Tc-99m small animal pinhole SPECT imaging,” in Proc. High Resolution Imaging in Small Animals: Instrumentation, Applications and Animal Handling Conf., Rockville, MD, 2001

R.Pani, et al., “Very high resolution gamma camera based on position sensitive photomultiplier tube,” Physica Medica, Vol. 9, No. 2-3, pp. 233-236, 1993

A.Trueman, et al., “Pixellated Csi(Tl) arrays with position-sensitive PMT readout,” Nucl. Instrum. Methods A, Vol. 353, No. 1994, pp. 375-378, 1994

R. Wojcik, et al., “High spatial resolution gamma imaging detector based on 5’’ diameter R3292 Hamamatsu PSPMT”, IEEE Trans Nucl Sci. Vol. 45, pp. 487-491, 1998

Hamamatsu Corporation, Bridgewater, New Jersey, USA

R. L. Clancy, C. J. Thompson, J. L. Robar, A. M. Bergman, “A Simple Technique to Increase the Linearity and Field-of-View in Position Sensitive Photomultiplier Tubes”, IEEE Trans. Nucl. Sci., Vol. 44, No. 3, pp. 494-498, 2002, 1997

H. Barrett, W. Swindell, Radiological imaging: The theory of imaging formation, detection, and processing, Vol. 1 & 2, New York: Academic Press, 1981

QI Yu-Jin, “High-resolution SPECT for small-animal imaging” Nuclear Science and Techniques“. Vol. 17. No. 3, pp. 164-169, 2006

D. Steinbach, S. Majewski, M. Williams, B. Kross, A. G. Weisenberger, R. Wojcik, “Development of a small field of view scintimammography camera based on a YAP crystal array and a position sensitive PMT”, IEEE Med. Imag. Conf. Conf. Rec., pp. 1251–1256, 1997

G. F. Knoll, Radiation Detection and Measurement, (Singarore: John Wiley & Sons), 2nd edition, 1989

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