Assessment of four scatter correction methods in In-111 SPECT imaging: A simulation study

Abstract

Introduction: Detection of compton scattered photons is one of the most important factors affecting the quality of single-photon emission computed tomography (SPECT) images. In most cases, the multiple-energy window acquisition methods are used for estimation of the scatter contribution into the main energy window(s) used in imaging. Aims and Objectives: The purpose of this study is to evaluate and compare the performance of four different scatter correction methods in In-111 SPECT imaging. Due to the lack of sufficient studies in this field, it can be useful to perform a more detailed and comparative study. Materials and Methods: Four approximations for scatter correction of In-111 SPECT images are evaluated by using the Monte Carlo simulation. These methods are firstly applied on each of photopeak windows, separately. Then, the effect of the correction methods is investigated by considering both the photopeak windows. The images obtained from a simulated multiple-spheres phantom are used for the evaluation of the correction methods by using three assessment criteria, including the image contrast, relative noise, and the recovery coefficient. Results: The results of this study show that the correction methods, when using the single photopeak windows, result in increase in image contrast with a significant level of noise. In return, when both the photopeak energy windows are used for imaging, it is possible to achieve the better image characteristics. Conclusion: The use of the proposed correction methods, by considering both the photopeak windows, leads to improve the image contrast with a reasonable level of image noise.

A study on energy window-based scatter correction methods in 99mTc and 123I imaging

“…It is clearly seen that the contrast of the scatter-corrected images is better than uncorrected ones, as mentioned by other studies [7,10,20,25]. When the contrast data is compared, it is recognized that the scatter window with 92-125 keV gave the best 99m Tc images (figure 10(a,c).…”

“…Such that, in 99m Tc imaging, approximately 30% of the photons detected in the primary energy window can arise from Compton scattered photons [4][5][6]. Therefore, one of the major problems in both planar and SPECT imaging is detection of these Compton-scattered photons degrade image quality by carrying misleading information about the photon's emission point [7][8][9][10].…”

“…It is mentioned that the total amount of the penetrated high-energy photons in the photopeak window could be 49%-60% of the detected photons [15]. Different publications have emphasized that these penetration and scatter events degrade image quality [2,3,10,11,16].…”

Investigation of different components of parallel-hole collimator response to different radioisotope energies used in nuclear medicine imaging

“…The quality of images obtained from the nuclear medicine imaging systems is affected by different factors such as the physical properties of detector[ 1 2 ] and collimator,[ 3 4 5 ] image reconstruction algorithms,[ 6 7 ] photon attenuation[ 8 9 10 ] and scattering,[ 11 12 13 ] and patient motion. [ 14 15 16 ] The use of a suitable collimator when imaging with a given radioisotope is an essential factor to produce the high quality images.…”