1Department of Medical Physics, Faculty of Health Sciences, SMU, Pretoria, South Africa
2Department of Physics, Faculty of Pre-Clinical Sciences, SMU, Pretoria, South Africa
3Department of Nuclear Medicine, Dr. George Mukhari Academic Hospital, Pretoria, South Africa
Introduction: The limited resolution of the imaging system causes partial volume effects (PVEs). These results in spreading of image counts to the neighboring pixels. This phenomenon is called spill-out effect. This study aimed at quantifying PVEs using ImageJ. Methods:Technetium-99m solution of concentration of 74 kBq/ml was filled into spheres A, B and C of diameters: 26 mm, 20 mm and 16 mm respectively. The spheres were imaged mounted inside a Jaszczak phantom filled with activity free water using a Siemens E-Cam dual head gamma camera. Images were quantified using ImageJ following a two-step method. Step 1: Drawing of region of interest 1 (ROI 1) closely on the boundary of the planar image to extract images counts before PVEs correction. Step 2: Drawing region of interest 2 (ROI 2) to extract true sphere image counts. ROI 2 extends from the boundary of ROI 1 by the FWHM of the imaging system. Results:The studyrevealed that PVEs are aggravated by decrease in sphere size. Underestimation of image counts on the 64 × 64 pixels matrix was found to be: 9.7%; 15% and 26% in the order of decreasing sphere size. However, an improvement in the spatial resolution decreased PVEs (128 × 128 pixels: 6.7%; 12.0% and 22.5%; 256 × 256 pixels: 6.5% ; 9% and 19.3%; 256 × 256 pixels: 6.1%; 8.0% and 18.7% in the order of decreasing sphere size). Conclusion: ImageJ successfully quantified PVEs attributed to the spill-out effect in planar imaging.
Buvat I. Quantification in emission tomography: challenges, solution, and performance. Nucl Instrum Meth A. 2007;571:10-13.
Erlandsson K, Buvat I, Pretorius PH, Thomas BA, Hutton BF. A review of partial volume correction techniques for emission tomography and their applications in neurology, cardiology and oncology. Phys Med Biol. 2012 Nov 7;57(21):R119-59.
Hofheinz F, Dittrich S, Pötzsch C, Hoff Jv. Effects of cold sphere walls in PET phantom measurements on the volume reproducing threshold. Phys Med Biol. 2010 Feb 21;55(4):1099-113.
Kirov AS, Pia JZ, Scmidtlein CR. Partial volume correction in PET using iterative deconvolution with variance control based on local topology. Available from: http://www.iop.orgEJ/abstract/0031-9155/53/10/009. [cited 2015 Dec 1]
Teo BK, Seo Y, Bacharach SL, Carrasquillo JA, Libutti SK, Shukla H, Hasegawa BH, Hawkins RA, Franc BL. Partial-volume correction in PET: validation of an iterative postreconstruction method with phantom and patient data. J Nucl Med. 2007 May;48(5):802-10.
Strul D, Bendriem B. Robustness of anatomically guided pixel-by-pixel algorithms for partial volume effect correction in positron emission tomography. J Cereb Blood Flow Metab. 1999 May;19(5):547-59.
Hoetjes NJ, van Velden FH, Hoekstra OS, Hoekstra CJ, Krak NC, Lammertsma AA, Boellaard R. Partial volume correction strategies for quantitative FDG PET in oncology. Eur J Nucl Med Mol Imaging. 2010 Aug;37(9):1679-87.
Soret M, Bacharach SL, Buvat I. Partial-volume effect in PET tumor imaging. J Nucl Med. 2007 Jun;48(6):932-45.
Erlandsson K, Thomas B, Dickson Hutton BF. Partial Volume correction in SPECT reconstruction with OSEM. Nucl Instrum Methods. 2011;646:S85-S88.
Du Y, Madar I, Stumpf MJ, Rong X, Fung GS, Frey EC. Compensation for spill-in and spill-out partial volume effects in cardiac PET imaging. J Nucl Cardiol. 2013 Feb;20(1):84-98.
Pretorius PH, King MA. Diminishing the impact of the partial volume effect in cardiac SPECT perfusion imaging. Med Phys. 2009 Jan;36(1):105-15.
Rosset OG, Zaidi H. Correction of Partial Volume effects in Emission Tomography. In: Zaidi H. Quantitative analysis in nuclear medicine imaging. New York: Springer Science Business Media, Inc.; 2006. p.237-265.
Green AJ, Dewhurst SE, Begent RH, Bagshawe KD, Riggs SJ.Accurate quantification of 131I distribution by gamma camera imaging. Eur J Nucl Med. 1990;16(4-6):361-5.