Abstract
We investigated scatter correction in transmission computed tomography (TCT) imaging by the combination of an uncollimated transmission source and a parallel-hole collimator. We employed the triple energy window (TEW) as the scatter correction and found that the conventional TEW method, which is accurate in emission computed tomography (ECT) imaging, needs some modification in TCT imaging based on our phantom studies. In this study a Tc-99m uncollimated line array source (area: 55 cm × 40 cm) was attached to one camera head of a dual-head gamma camera as a transmission source, and TCT data were acquired with a low-energy, general purpose (LEGP), parallel-hole collimator equipped on the other camera head. The energy spectra for 140 keV-photons transmitted through various attenuating material thicknesses were measured and analyzed for scatter fraction. The results of the energy spectra showed that the photons transmitted had an energy distribution that constructs a scatter peak within the 140 keV-photopeak energy window. In TCT imaging with a cylindrical water phantom, the conventional TEW method with triangle estimates (subtraction factor,K = 0.5) was not sufficient for accurate scatter correction (μ = 0.131 cm-1 for water), whereas the modified TEW method withK= 1.0 gave the accurate attenuation coefficient of 0.153 cm-1 for water. For the TCT imaging with the combination of the uncollimated Tc-99m line array source and parallel hole collimator, the modified TEW method withK = 1.0 gives the accurate TCT data for quantitative SPECT imaging in comparison with the conventional TEW method withK= 0.5.
Similar content being viewed by others
References
Jaszczak RJ, Green KL, Floyd CE, Harris CC, Coleman RE. Improved SPECT quantification using compensation for scattered photons.J Nucl Med 1984; 25: 893–900.
Ogawa K, Harata Y, Ichihara Y, Kubo A, Hashimoto S. A practical method for position-dependent Compton-scatter correction in single photon emission CT.IEEE Trans Med Imag 1991; 10:408–412.
Kojima A, Matsumoto M, Takahashi M, Uehara S. Effect of energy resolution on scatter fraction in scintigraphic imaging: Monte Carlo study.Med Phys 1993; 20: 1107–1113.
Kojima A, Tsuji A, Takaki Y, Tomiguchi S, Hara M, Matsumoto M, et al. Correction of scattered photons in Tc-99m imaging by means of a photopeak dual-energy window acquisition.Ann Nucl Med 1992; 6: 153–158.
Ichihara T, Ogawa K, Motomura N, Kubo A, Hashimoto S. Compton scatter compensation using the triple-energy window method for single- and dual-isotope SPECT.J Nucl Med 1993; 34: 2216–2221.
Buvat I, Rodriguez-Villafuerte M, Todd-Pokropet A, Benali H, Di Paola R. Comparative assessment of nine scatter correction methods based on spectral analysis using Monte Carlo simulations.J Nucl Med 1995; 36: 1476–1488.
Haynor DR, Kaplan MS, Miyaoka RS, Lewellen TK. Multiwindow scatter correction techniques in single-photon imaging.Med Phys 1995; 22: 2015–2024.
Beekman FJ, Kamphuis C, Frey EC. Scatter compensation methods in 3D iterative SPECT reconstruction: A simulation study.Phys Med Biol 1997; 42: 1619–1632.
Kojima A, Matsumoto M, Ohyama Y, Tomiguchi S, Kira M, Takahashi M. Scatter correction with an off-peak triple energy window method in Thallium-201 imaging.Jpn J Mucl Med 1997; 35: 789–796.
Welch A, Gullberg GT, Christian PE, Datz FL, Morgan H. A transmission-map-based scatter correction technique for SPECT in inhomogeneous media.Med Phys 1995; 22:1627–1635.
Ichihara T, Motomura N, Ogawa K, Hasegawa H, Hashimoto J, Kubo A. Evaluation of SPET quantification of simultaneous emission and transmission imaging of the brain using a multidetector SPET system with the TEW scatter compensation method and fan-beam collimation.Eur J Nucl Med 1996; 23: 1292–1299.
Ichihara T, Maeda H, Yamakado K, Motomura N, Matsumura K, Takeda K, et al. Quantitative analysis of scatter- and attenuation-compensated dynamic single-photon emission tomography for functional hepatic imaging with a recepter-binding radiopharmaceutical.Eur J Nucl Med 1997; 24; 59–67.
Ogawa K, Takagi Y, Kubo A, Hashimoto S, Sanmiya T, Okano Y, et al. An attenuation correction method of single photon emission computed tomography using gamma ray transmission CT.KAKU IGAKU (Jpn J Nucl Med) 1985;22: 477–490.
Malko JA, Van Heertum RL, Gullberg GT, Kowalsky WP. SPECT liver imaging using an iterative attenuation correction algorithm and an external flood source.J Nucl Med 1986;27:701–705.
Cao Z, Tsui BMW. Performance characteristics of transmission imaging using a uniform sheet source with parallel-hole collimation.Med Phys 1992; 19: 1250–1212.
Frey EC, Tsui BMW, Perry JR. Simultaneous acquisition of emission and transmission data for improved Thallium-201 cardiac SPECT imaging using a Technetium-99m transmission source.J Nucl Med 1992; 33: 2238–2245.
Jaszczak RJ, Gilland DR, Hanson MW, Jang S, Greer KL, Coleman RE. Fast transmission CT for determining attenuation maps using a collimated line source, rotatable air-copper-lead attenuators and fan-beam collimation.J Nucl Med 1993; 34: 1577–1586.
Tan P, Bailey DL, Meikle SR, Eberl S, Fulton RR, Hutton BF. A scanning line source for simultaneous emission and transmission measurements in SPECT.J Nucl Med 1993;34: 1752–1760.
King MA, Tsui BMW, Pan T-S. Attenuation compensation for cardiac single-photon emission computed tomographic imaging: Part 1. Impact of attenuation and methods of estimating attenuation maps.J Nucl Cardiol 1995; 2: 513–524.
King MA. Tsui BMW, Pan T-S, Glick SJ. Soares EJ. Attenuation compensation for cardiac single-photon emission computed tomographic imaging: Part 2. Attenuation compensation algorithms.J Nucl Cardiol 1996; 3: 55–63.
Tomiguchi S, Oyama Y, Kira T, Kira M, Nakashima R, Tsuji A, et al. Evaluation of simultaneous acquisition of transmission and emission data on Thallium-201 myocardial SPECT.KAKU IGAKU (Jpn J Nucl Med) 1996; 33:1027–1035.
Tomiguchi S, Kojima A, Oyama Y, Kira T, Yokoyama T, Kira M, et al. Development of asymmetric fan-beam transmission CT on two-head SPECT system, [abstract]J Nucl Med 1997;38(Suppl):212.
Kojima A, Ohyama Y, Tomiguchi S, Kira M, Matsumoto M, Takahashi M. Quantitative planar imaging method for measurement of renal activity using a conjugate-emission image and transmission data.Med Phys 2000; 27: 608–615.
Ogawa K, Kawamura Y, Kubo A, Ichihara T. Estimation of scattered photons in gamma ray transmission CT using Monte Carlo simulations.IEEE Trans Nucl Sci 1997; 44:1225–1230.
Kojima A, Ohyama Y, Tomiguchi S, Kira M, Matsumoto M, Takahashi M. Attenuation correction using combination of a parallel hole collimator and an uncollimated nonuniform line array source. [abstract]J Nucl Med 1999; 40 (Suppl): p303.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Kojima, A., Matsumoto, M., Tomiguchi, S. et al. Accurate scatter correction for transmission computed tomography using an uncollimated line array source. Ann Nucl Med 18, 45–50 (2004). https://doi.org/10.1007/BF02985613
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF02985613