Activity optimization method in SPECT: A comparison with ROC analysis

Díaz, Marlen Pérez; Rizo, Oscar Díaz; Díaz, Adlin López; Aparicio, Eric Estévez; Díaz, Rafael Gonzales

doi:10.1631/jzus.2006.b0947

Cited by 3 publications

(2 citation statements)

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“…A similar approach was used, in particular, in analysis of brain by SPECT in the diagnosis of Alzheimer's disease [6]. It should also be noted that the quality of radionuclide images is limited not only by hardware capabilities, but also by the number of radiopharmaceuticals administered to the patient and the functional state of other organs and systems [7][8][9]. There are a significant shift of the histogram of velocity distribution of radioactive count rate (CR) and a change in the maximum CR in smoothing SPECT.…”

Section: Introductionmentioning

confidence: 99%

Gaussian Filter for Brain SPECT Imaging

Николов

Makeyev

Korostynska

et al. 2022

Innov Biosyst Bioeng

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Background. The presence of a noise component on 3D images of single-photon emission computed tomography (SPECT) of a brain significantly distorts the probability distribution function (PD) of the radioactive count rate in the images. The presence of noise and further filtering of the data, based on a subjective assessment of image quality, have a significant impact on the calculation of volumetric cerebral blood flow and the values of the uptake asymmetry of the radiopharmaceutical in a brain. Objective. We are aimed to develop a method for optimal SPECT filtering of brain images with lipophilic radiopharmaceuticals, based on a Gaussian filter (GF), for subsequent image segmentation by the threshold method. Methods. SPECT images of the water phantom and the brain of patients with 99mTc-HMPAO were used. We have developed a technique for artificial addition of speckle noise to conditionally flawless data in order to determine the optimal parameters for smoothing SPECT, based on a GF. The quantitative criterion for optimal smoothing was the standard deviation between the PD of radioactive count rate of the smoothed image and conditionally ideal one. Results. It was shown that the maximum radioactive count rate of the SPECT image has an extremum by changing the standard deviation of the GF in the range of 0.3–0.4 pixels. The greater the noise component in the SPECT image, the more quasi-linearly the corresponding rate changes. This dependence allows determining the optimal smoothing parameters. The application of the developed smoothing technique allows restoring the probability distribution function of the radioactive count rate (distribution histogram) with an accuracy up to 5–10%. This provides the possibility to standardize SPECT images of brain. Conclusions. The research results of work solve a specific applied problem: restoration of the histogram of a radiopharmaceuticals distribution in a brain for correct quantitative assessment of regional cerebral blood flow. In contrast to the well-known publications on the filtration of SPECT data, the work takes into account that the initial tomographic data are 3D, rather than 2D slices, and contain not only uniform random Gaussian noise, but also a pronounced speckle component.

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Section: Introductionmentioning

confidence: 99%

Gaussian Filter for Brain SPECT Imaging

Николов

Makeyev

Korostynska

et al. 2022

Innov Biosyst Bioeng

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“…Few years later a discriminant method for optimizing activity was presented in nuclear medicine studies which is validated by comparison with receiver operating characteristics (ROC) curves [7].…”

Section: Introductionmentioning

confidence: 99%

Quantitative evaluation of the administrated dose affecting image quality in myocardial perfusion SPECT

El-Gebaly

Maamoun

Madian

2014

Journal of X-Ray Science and Technology: Clinical Applications

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BACKGROUND: Myocardial perfusion imaging (MPI) can provide the valuable cardiac functions.Image quality in nuclear medicine tomography is critically dependent on the activity administered into patients. OBJECTIVE: This study was designed to evaluate the optimum injected dose of 99mTc-MIBI for quantitative assessment of image quality as compared with standard injected dose used for that purpose. METHODS: The image quality parameters (Contrast, relative noise and contrast to noise ratio) were determined in 32 patients (21 male, 11 female, age 45-60 y) with weight 60 ± 15 kg. Patients were classified into four groups; each one consisted of 8 patients. The first group received 370 MBq, the second one received 555 MBq, the third group received 740 MBq and the last group received 925 MBq. RESULTS: Qualitative assessments of the images revealed equivalent scintigraphic patterns in all patients. There was a significant difference in the image contrast. The image contrast in the 370 MBq group was greater than other groups. The image noise between the four groups was significantly different. It increased with injected dose reduction. Contrast to noise ratio (CNR) was significantly different between 370 MBq and other groups. CONCLUSION: It is concluded that results from the first group which received 370 MBq are sufficiently similar to those of the fourth group (standard group) which received 925 MBq. Consequently,accurate estimations of differential cardiac functions are possible with the 370 MBq dose.

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