1Abdullah Waidi Idris, 1Arihasliza Ariffin, 2Ahmad Zakaria
1School of Health Sciences, USM, Kelantan.
2Dept. of Nuclear Medicine, Radiotherapy & Oncology, School of Medical Sciences, USM, Kelantan.
National Seminar on Medical Physics;
27th & 28th August 2005; De Rhu Beach Resort, Kuantan, Pahang
Jointly Organised by: International Islamic University Malaysia
& Malaysian Association of Medical Physics (MAMP)
Abstract
The objective of this study is to estimate the volume of organ of different sizes using the Single Photon Emission Computed Tomography (SPECT) technique. This method was chosen due to the 3-dimensional data imaging compared to the 2-dimensional data planar imaging.
In this study, the acrylic phantom (with various sizes of cylindrical insert of known volume simulating the ‘hot’ lesion) had been used. This phantom was filled with 20 mCi of 99mTc. The data was then acquired using gamma camera and SPECT system using LEHR collimator, 64 x 64 matrix size and 64 views of projection (30 seconds per projection). Subsequently, the acquired data were reconstructed using the filtered back-projection technique: Ramp and Butterworth filter: order = 5, cut-off frequency = 0.35 Nyquist.
The radius of each cylinder was measured and the volumes were calculated by this formula ; V = πr2 Х pixel size Х total number of slice. Then, a regression analysis was made for true and calculated volumes of each cylinder.
The correlation coefficient obtained was 0.988 with a different percentage of less than 20%. As conclusion, this SPECT technique can be applied to estimate a size of any lesion in a clinical study.
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