Salivary gland scintigraphy with partial volume effects quantification: A phantom feasibility study

Nyathi, Mpumelelo; Sithole, Mpho Enoch

doi:10.21767/amj.2017.3056

Cited by 1 publication

(2 citation statements)

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“…As also shown in Figure 7, the distribution of image counts to the adjacent pixels led to the fuzzy shape of the planar images of the spheres. Similar to the results, [5] quantified the PVEs of planar imaging of Technetium-99m ( 99m TC) in Jaszczak phantom using two ROIs with different sizes, and they found that PVEs were worsened by the reduction of the sphere size. In this regard, they reported that with the plummeting pixel size (with the increasing matrix size), the underestimation of image counts was improved [5].…”

Section: Discussionsupporting

confidence: 61%

“…Nevertheless, the poor spatial resolution of the nuclear medicine imaging system, either planar scintigraphy or single photon emission tomography (SPECT), obstructs precise quantification. In these modalities, activity concentrations in organs smaller than two or three times the full-width half maximum (FWHM) of the imaging system’s point spread function are often underestimated or overestimated, which is named partial volume effects (PVEs) [4,5]. These effects might lead to the apparent distribution of activity from inside the region of interest (ROI) into the adjacent region (spill-out effect) or integrating the activity outside the ROI into the targeted region (spill-in effect) [6,7].…”

Section: Introductionmentioning

confidence: 99%

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Quantifying partial volume effect in SPECT and planar imaging: optimizing region of interest for activity concentration estimation in different sphere sizes

Jalilifar,

Sadeghi,

Emami-Ardekani

et al. 2024

Nuclear Medicine Communications

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Introduction To quantify the partial volume effect in single photon emission tomography (SPECT) and planar images of Carlson phantom as well as providing an optimum region of interest (ROI) required to more accurately estimate the activity concentration for different sphere sizes. Methods 131I solution with the 161.16 kBq/ml concentration was uniformly filled into the different spheres of Carlson phantom (cold background condition) with the diameters of 7.3, 9.2, 11.4, 14.3, 17.9, 22.4 and 29.9 mm, and there was no background activity. In the hot background condition, the spheres were filled with the solution of 131I with the 1276.5 kBq/ml addition to the background activity concentration of 161.16 kBq/ml in all the phantoms. The spheres were mounted inside the phantom and underwent SPECT and planar images. ROI was drawn closely on the boundary of each sphere image and it was extended to extract the true count. Results In the cold background condition, the recovery coefficient (RC) value for SPECT images ranged between 0.8 and 1.03. However, in planar imaging, the RC value was 0.72 for the smallest sphere size and it increased for larger spheres until 0.98 for 29.9 mm. In the hot background condition, the RC value for sphere diameters larger than 20 mm was overestimated more than in the cold background condition. The ROI/size required to more accurately determine activity concentration for the cold background ranged from 1.18 to 2.7. However, in the hot background condition, this ratio varied from 1.34 to 4.05. Conclusion In the quantification of partial volume effects, the spill-out effect seems to play a crucial role in the distribution of the image counts beyond the boundaries of the image pixels. However, more investigations are needed to accurately characterize limitations regarding the object size, background levels, and other factors.

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Section: Discussionsupporting

confidence: 61%