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

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: 131 I 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 131 I 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.

DEVELOPMENT AND ESTIMATION OF HUMAN DOSIMETRY OF A NEW 47SC-RISEDRONATE FOR RADIOPHARMACEUTICAL APPLICATION.

Bisphosphonate risedronate (2-(3-pyridinyl)-1-hydroxyethane diphosphonic acid) was radiolabeled with scandium-47 (47Sc) as potential therapeutic radiopharmaceutical for skeletal metastases. Its time-dependent biodistribution in mice was measured and its human dosimetry was derived. The labelling process was performed at 95 °C for 30 min. The stability of the radio-conjugate was tested in human serum at 37 °C and its biodistribution was studied in balb/c mice. The radiochemical yield of ≥90% was obtained corresponding to a specific activity of 277 MBq/mg. The radio-conjugate showed good stability in human serum up to 48 h. A high bone uptake by 48 h post-injection was achieved, which suggests that 47Sc-risedronate may be therapeutically beneficial for the palliation of painful bone metastasis. The estimated absorbed dose coefficient and the time-integrated activity coefficient (ã (rs, TD)) in the bone were 1.35 mGy/MBq and 31.04 (Bq-h/Bq), respectively. The absorbed doses to non-osseous normal organs were much lower than that to the bone.

Quantitative Analysis of the Antiepileptogenic Effects of Low Frequency Stimulation Applied Prior or After Kindling Stimulation in Rats.

Background and Objective: Developing quantitative measures based on spectral analysis of electroencephalograph (EEG) recordings of neural activities plays an important role in developing efficient treatments for epilepsy. Such biomarkers can be used for developing open or closed loop approaches for seizure prediction or prevention. This study aims to quantitatively evaluate antiepileptogenic effects of low frequency stimulation (LFS) applied immediately before or after kindling stimulations using spectral power analysis of extracellular EEG in rat. Methods: Nineteen adult rats were used: seven for kindle, six for LFS+Kindle (LFSK) and six for Kindle+LFS (KLFS). Four packages of LFS (1Hz) were applied immediately before or after rapid kindling stimulations. The power spectral densities of afterdischarge (AD) sections of EEG corresponding to different stages of kindling for delta (0-4 Hz), theta (4-8 Hz), alpha (8-12 Hz), beta (12-28 Hz), gamma (28-40 Hz) sub-bands, and theta/alpha ratio were comparatively investigated. Moreover, correlation between AD duration (ADD) and its different frequency components was calculated. Results: Both LFSK and KLFS significantly increased delta and reduced beta and gamma oscillations, compared with kindle group. However, just the reduction in LFSK group was significant. Both protocols increased theta/alpha ratio, but just LFSK showed significant increase (p < 0.05). Although LFSK enhanced theta/alpha ratio more than KLFS, the difference was not statistically significant. Furthermore, strong correlation between each frequency sub band and ADD was not observed in kindle and LFS treated groups (both LFSK and KLFS). Conclusion: Although behavioral assessments showed relatively the same level of antiepileptogenic effects for KLFS and LFSK, quantitative assessments showed more significant differences in the quantitative measures between the two protocols. Developing more quantitative EEG based measures correlated with LFS-induced effects can facilitate developing open or closed loop seizure prevention modalities.

Improving cognitive task in kindled rats by using low frequency stimulation during epileptogenesis.

Numerous studies indicate that one of the bad effects of epilepsy is cognitive impairment. In this study we focused on the effect of LFS as a potential anticonvulsant agent, during epileptogenesis on cognitive impairments induced by amygdala kindling in rat. Twenty-one adult rats were divided into 3 groups including control (n = 7), kindled (n = 7), and Kindled+LFS (KLFS) (n = 7). Animals in the kindled group received kindling stimulation in a rapid kindling manner (a 3 s train of 50 Hz monophasic pulses of 1 ms duration, 12 times a day) in amygdala whereas control animals had no stimulation. Four packages of LFS (each package consisting of 200 monophasic square pulses, 0.1 ms pulse duration at 1 Hz) were applied daily after termination of kindling stimulation in KLFS group. Spatial memory of all animals was tested using radial arm maze after termination of stimulation on acquisition trial days and 14 days after the final acquisition trial test. Epileptogenesis process significantly increased working and reference memory error compared to control groups whereas application of LFS immediately after kindling stimulation prevented this impairment in 8 arm radial maze and there was no significant difference between KLS and control groups. Our results indicated that application of LFS during kindling acquisition suppresses memory impairment in epileptogenesis by kindling stimulation.

Dataset of quantitative spectral EEG of different stages of kindling acquisition in rats.

The data represented here are in relation with the manuscript "Quantitative assessments of extracellular EEG to classify specific features of main phases of seizure acquisition based on kindling model in Rat" (Jalilifar et al., 2017) [1] which quantitatively classified different main stages of the kindling process based on their electrophysiological characteristics using EEG signal processing. The data in the graphical form reported the contribution of different sub bands of EEG in different stages of kindling- induced epileptogenesis. Only EEG signals related to stages 1-2 (initial seizure stages (ISSs)), 3 (localized seizure stage (LSS)), and 4-5 (generalized seizure stages (GSSs) were transferred into frequency function by Fast Fourier Transform (FFT) and their power spectrum and power of each sub bands including delta (1-4 Hz), Theta (4-8 Hz), alpha (8-12 Hz), beta (12-28 Hz), gamma (28-40 Hz) were calculated with MATLAB 2013b. Accordingly, all results were obtained quantitatively which can contribute to reduce the errors in the behavioral assessments.

Quantitative assessments of extracellular EEG to classify specific features of main phases of seizure acquisition based on kindling model in Rat.

OBJECTIVE: Quantitative assessments of extracellular EEG to identify specific features of three main phases of seizure acquisition based on kindling model in Rat. METHODS: Male rats were divided into 2 groups including kindled (n=10) and sham (n=7) and respectively underwent an amygdala rapid kindling and placebo kindling. EEG signals in stages 1-2 (initial seizure stages (ISSs)), 3 (localized seizure stage (LSS)), and 4-5 generalized seizure stages (GSSs) were divided into 5 bands: delta (0-4Hz), theta (4-8Hz), alpha (8-12Hz), beta (12-28Hz), and gamma (28-40Hz). Spectral power of the sub bands and the ratios of theta/alpha and delta/beta were compared in the three phases and between the sham and kindling groups. RESULTS: Beta power significantly increased during kindling acquisition, though it was significantly lower than sham. Delta oscillation in ISSs was higher than LSS and GSSs, but the difference was significant only with LSS. Moreover, delta power was higher in all stages of kindling than sham. Gamma power in all stages of kindling was significantly lower than sham. Alpha power was significantly reduced in ISSs, compared with sham, but gradually increased during epileptogenesis. Theta/alpha and delta/beta increased in all stages, compared with sham (p<0.05). Theta/alpha significantly decreased in LSS and GSSs, compared with ISSs (p<0.05). Delta/beta decreased during kindling, but it was significantly different only between ISSs and LSS (P<0.05). CONCLUSION: Beta and alpha oscillations at ISSs significantly decreased, but gradually increased along with kindling progression. Furthermore, delta power significantly increased during kindling process.

Low Frequency Electrical Stimulation Either Prior to Or after Rapid Kindling Stimulation Inhibits the Kindling-Induced Epileptogenesis.

Objective. Studies are ongoing to find appropriate low frequency stimulation (LFS) protocol for treatment of epilepsy. The present study aimed at assessing the antiepileptogenesis effects of LFS with the same protocol applied either just before or immediately after kindling stimulations. Method. This experimental animal study was conducted on adult Wistar rats (200 ± 20 g) randomly divided into kindle (n = 7), LFS + Kindle (n = 6), and Kindle + LFS groups (n = 6). All animals underwent rapid kindling procedure and four packages of LFS (1 Hz) with 5 min interval were applied either immediately before (LFS-K) or after kindling stimulation (K-LFS). The after discharge duration (ADD), daily stages of kindling, and kindling seizure stage and number of stimulations required to reach each stage were compared between the three groups using two-way analysis of variance (ANOVA) followed by Tukey post hoc and one-way ANOVA, and Kruskal-Wallis test, respectively. Results. LFS in both protocols significantly decreased the ADD (p < 0.05) and daily seizure stages (p < 0.05) and increased the number of stimulations required to achieve stage 3 and stages 4 and 5 of kindling compared with the kindle group (stage 2: p > 0.05, stages 3 to 5: p < 0.05). Conclusion. Although LFS-K showed more inhibiting effect than K-LFS, the difference was not statistically significant.

Ultrasound-based Techniques as Alternative Treatments for Chronic Wounds: A Comprehensive Review of Clinical Applications.

Ultrasound (US) waves have been recently developed for the treatment of different chronic wounds with promising therapeutic outcomes. However, the clinical efficacy of these techniques is still not fully understood and standard guidelines on dose ranges and possible side effects should be determined. This paper aims to comprehensively review the recent advances in US techniques for chronic wound treatment, their therapeutic efficacies, and clinical considerations and challenges. The databases of PubMed (1985-2017), EMBASE (1985-2017), Web of Sciences (1985-2017), Cochrane central library (1990-2017), and Google Scholar (1980-2017) were searched using the set terms. The obtained results were screened for the title and abstract by two authors and the relevant papers were reviewed for further details. Preclinical and clinical studies have shown strong evidence on the therapeutic efficiency of US in chronic wounds. The main limitation on developing clinical standard protocols of US for treatment of wounds is the lack of definite dose-response for each wound. However, spatial average temporal average is the main parameter for defining US dosage in wound treatment. The range of 0.5 to 3 W/cm2 is a range of dose exerting significant therapeutic outcomes and minimum adverse effects. Low-frequency US waves can accelerate the healing speed of open wounds as well as deep-tissue injuries. In addition, US waves show promising therapeutic efficacy for chronic wounds. To develop clinical US protocol for each wound type, further in vitro and in vivo preclinical and clinical trials are needed to reach an exact dose-response for each wound type.

Classifying amygdala kindling stages using quantitative assessments of extracellular recording of EEG in rats.

PURPOSE: Determining different seizure stage specific features in a kindling model is a crucial step in developing efficient objective techniques for early prediction and treatment of seizures. This study identified and categorized kindling stages based on their electrophysiological features through processing extracellular field potentials of Amygdala rapid kindling. METHODS: Thirteen Wistar rats (200±10g) were divided into 2 groups including kindle (n=7) and sham (n=6) and respectively underwent an amygdala rapid kindling and placebo stimulation. EEG signals in each stage were classified into 7 bands: delta (0-4Hz), theta (4-8Hz), alpha (8-12Hz), low beta (12-16Hz), mid beta (16-20Hz), high beta (20-28Hz) and gamma (28-40Hz). Spectral power and power of sub bands of stage 3 (localized seizure stage (SS)) and stages 4 and 5 (generalized SSs) were compared between kindling and sham groups. RESULT: Spectral analyses showed larger spikes in delta and theta subbands in the stages of 3, 4, and 5 of kindling, compared with sham animals. Generalized SSs contained more spikes than the localized SS in the kindling. Kindling process was accompanied by reduction in high beta and gamma oscillations and increase in delta sub band power which were significant in the generalized SSs. The theta/alpha ratio in the localized SS was higher than the generalized SSs and sham group, but the difference with the sham group was statistically significant. CONCLUSION: Our results showed that reduced high beta and gamma and increased delta oscillations power are associated with behavioral seizure progression.