Randomized, crossover trial: comparing the effects of standardized egg-white meal and Vital® on global gastric emptying parameters and intragastric meal distribution in healthy Asian participants.

BACKGROUND AND AIM: Measurements of gastric emptying and accommodation for alternative test-meal protocol during gastric emptying scintigraphy (GES), such as high-calorie nutrient drinks, are not fully established. We aimed to compare the effects of standardized egg-white meal (EWM) versus high-calorie nutrient drink (Vital®; Abbott Laboratories) on global GES parameters and intragastric meal distribution at immediate scan (IMD0h). METHODS: Of 84 screened participants, 60 asymptomatic healthy Asian population (38 females; 24.0 ± 1.5 years; 23.8 ± 2.6 kg/m2) were recruited in this 2 × 2 (AB/BA) crossover trial. Participants were randomized to a 4-h GES with 99mTc-radiolabeled EWM (~255.8 kcal), followed by a 200 mL Vital® (300 kcal), or vice versa, separated by a 2-week washout period. Global meal retention (GMR), power-exponential model emptying parameters (half-emptying [T1/2], lag phases [Tlag2%, Tlag5%, Tlag10%]), and IMD0h were determined and compared. RESULTS: GMRs for both test meals were within the international standard references for solid GES. Compared to EWM, Vital® exhibited significantly lower GMRs (faster emptying) from 0.5 to 3 h (all P < 0.001) but comparable at 4 h (P = 0.153). Similar observations were found for the model-based T1/2 and the different Tlag thresholds (all P < 0.001). Furthermore, IMD0h was found to be lower with Vital®, indicating lower gastric accommodation (faster antral filling) immediately post-ingestion (P < 0.001). Both test meals showed significant moderate-to-strong positive associations at the late-phase GE (GMR 2-4 h, T1/2) (all P < 0.05). CONCLUSIONS: Overall, Vital® is an acceptable alternative test meal to the EWM for GES; however, exercise caution when interpreting early-phase GE. The normative values for global GES parameters and IMD0h are also established.

Development and validation of audio-based guided imagery and progressive muscle relaxation tools for functional bloating.

Mind-body techniques, including Guided Imagery (GI) or Progressive Muscle Relaxation (PMR), may effectively manage bloating. The current study aimed to develop and validate (psychometric and psychological responses) audio-based GI and PMR techniques for bloating. Audio scripts were first developed from literature reviews and in-depth interviews of participants with bloating diagnosed based on the Rome IV criteria. Scripts were validated using psychometric (content & face validity index) and physiological approaches (brain event-related potentials & heart rate variability). 45/63 participants completed the in-depth interview, and 'balloon' emerged as the synonymous imagery description for bloating, of which inflation correlated with a painful sensation. The final tools consisted of narrated audio scripts in the background of a validated choice of music. Overall, the content and face validity index for PMR and GI ranged from 0.92 to 1.00. For ERP and HRV, 17/20 participants were analyzed. For ERP, there was a significant difference between GI and PMR for alpha waves (p = 0.029), delta waves (p = 0.029), and between PMR and control for delta waves (p = 0.014). For HRV, GI and PMR exhibited similar autonomic responses over controls (overall p<0.05). The newly developed GI and PMR audio-based tools have been validated using psychometric and physiological approaches.

99mTc-sodium phytate is a valid alternative to the gold-standard 99mTc-sulfur colloid in the measurement of gastric emptying among healthy multi-ethnic Asian population: results of a randomized cross-over trial.

BACKGROUND: It is unclear if the 99mTc-sodium phytate (99mTc-SP) is as reliable as the gold-standard 99mTc-sulfur colloid (99mTc-SC) for gastric emptying scintigraphy (GES). This study is aimed to compare the emptying rates of both radiotracers in a prospective, randomized cross-over trial and to determine the normative data of a healthy multi-ethnic Asian population. METHODS: Out of the 44 healthy individuals screened, 31 (14 females; mean age: 28.4 ± 7.0 years) were enrolled and underwent GES using the standardized egg-white meal. All participants were randomly assigned to either 99mTc-SP or 99mTc-SC on the first GES session before crossed over to the other formulation after 2 weeks. RESULTS: Both kits achieved the radiochemical purities of > 95%. The median rate (95th upper normative limit) of gastric emptying, reported as total gastric meal retention between 99mTc-SP and 99mTc-SC, was found to be comparable at all measured time points: 0.5 h [85.0% (96.6%) vs. 82.0% (94.0%)], 1 h [70.0% (86.4%) vs. 65.0% (86.6%)], 2 h [31.0% (55.8%) vs. 25.0% (64.4%)], 3 h [7.0% (26.3%) vs. 5.0% (29.9%)], and 4 h [3.0% (10.3%) vs. 2.0% (9.9%)]; P > 0.05. In addition, both radiotracers correlated well (Kendall's Tau (τ) coefficient = 0.498, P < 0.001) and presented with a good agreement at the 4th-hour time frame based on the Bland-Altman plot analysis. CONCLUSIONS: 99mTc-SP is a valid radiotracer alternative to 99mTc-SC for routine GES examination. The normative values for both radiotracers have also been determined for the healthy multi-ethnic Asian population. TRIAL REGISTRATION: This trial was registered retrospectively in the Thai Clinical Trials Registry on May 23rd, 2020 (Identifier: TCTR20200526004; http://www.clinicaltrials.in.th/index.php?tp=regtrials&menu=trialsearch&smenu=fulltext&task=search&task2=view1&id=6296 ).

Standardized Uptake Value from Semiquantitative Bone Single-Photon Emission Computed Tomography/Computed Tomography in Normal Thoracic and Lumbar Vertebrae of Breast Cancer Patients.

STUDY DESIGN: Retrospective study. PURPOSE: This study aims to semiquantitatively evaluate the standardized uptake value (SUV) of 99mTc-methylene diphosphonate (MDP) radionuclide tracer in the normal vertebrae of breast cancer patients using an integrated single-photon emission computed tomography (SPECT)/computed tomography (CT) scanner. OVERVIEW OF LITERATURE: Molecular imaging techniques using gamma cameras and stand-alone SPECT have traditionally been utilized to evaluate metastatic bone diseases. However, these methods lack quantitative analysis capabilities, impeding accurate uptake characterization. METHODS: A total of 30 randomly selected female breast cancer patients were enrolled in this study. The SUV mean (SUVmean) and SUV maximum (SUVmax) values for 286 normal vertebrae at the thoracic and lumbar levels were calculated based on the patients' body weight (BW), body surface area (BSA), and lean body mass (LBM). Additionally, 106 degenerative joint disease (DJD) lesions of the spine were also characterized, and both their BW SUVmean and SUVmax values were obtained. A receiver operating characteristic (ROC) curve analysis was then performed to determine the cutoff value of SUV for differentiating DJD from normal vertebrae. RESULTS: The mean±standard deviations for the SUVmean and SUVmax in the normal vertebrae displayed a relatively wide variability: 3.92±0.27 and 6.51±0.72 for BW, 1.05±0.07 and 1.75±0.17 for BSA, and 2.70±0.19 and 4.50±0.44 for LBM, respectively. Generally, the SUVmean had a lower coefficient of variation than the SUVmax. For DJD, the mean±standard deviation for the BW SUVmean and SUVmax was 5.26±3.24 and 7.50±4.34, respectively. Based on the ROC curve, no optimal cutoff value was found to differentiate DJD from normal vertebrae. CONCLUSIONS: In this study, the SUV of 99mTc-MDP was successfully determined using SPECT/CT. This research provides an approach that could potentially aid in the clinical quantification of radionuclide uptake in normal vertebrae for the management of breast cancer patients.

Radiosensitization Effects by Bismuth Oxide Nanoparticles in Combination with Cisplatin for High Dose Rate Brachytherapy.

PURPOSE: The aim of this study was to investigate the potential of the synergetic triple therapeutic combination encompassing bismuth oxide nanoparticles (BiONPs), cisplatin (Cis), and high dose rate (HDR) brachytherapy with Ir-192 source in breast cancer and normal fibroblast cell line. METHODS: In vitro models of breast cancer cell lines (MCF-7, MDA-MB-231) and normal fibroblast cell line (NIH/3T3) were employed. Cellular localization and cytotoxicity studies were conducted prior to inspection on the radiosensitization effects and generation of reactive oxygen species (ROS) on three proposed radiosensitizers: BiONPs, Cis, and BiONPs-Cis combination (BC). The optimal, non-cytotoxic concentration of BiONPs (0.5 mM) and the 25% inhibitory concentration of Cis (1.30 µM) were applied. The radiosensitization effects were evaluated by using a 0.38 MeV Iridium-192 HDR brachytherapy source over a prescribed dose range of 0 Gy to 4 Gy. RESULTS: The cellular localization of BiONPs was visualized by light microscopy and accumulation of the BiONPs within the vicinity of the nuclear membrane was observed. Quantification of the sensitization enhancement ratio extrapolated from the survival curves indicates radiosensitization effects for MCF-7 and MDA-MB-231 when treated with BiONPs, Cis, and BC. However, NIH/3T3 cells exhibited contradictive behavior as it only reacted towards the BC combination. Nonetheless, the MCF-7 cell line loaded with BC shows the highest SER of 4.29. ROS production analysis, on the other hand, shows that Cis and BC radiosensitizers generated the highest free radicals in comparison to BiONPs alone. CONCLUSION: A BiONPs-Cis combination was unveiled as a novel approach that offers promising radiosensitization enhancement that will increase the efficiency of tumor control while preserving the normal tissue at a reduced dose. This data is the first precedent to prove the synergetic implication of BiONPs, Cis, and HDR brachytherapy that will be beneficial for future chemoradiotherapy strategies in cancer care.

Effect of scanning parameters on dose-response of radiochromic films irradiated with photon and electron beams.

Proper dosimetry settings are crucial in radiotherapy to ensure accurate radiation dose delivery. This work evaluated scanning parameters as affecting factors in reading the dose-response of EBT2 and EBT3 radiochromic films (RCFs) irradiated with clinical photon and electron beams. The RCFs were digitised using Epson® Expression® 10000XL flatbed scanner and image analyses of net optical density (netOD) were conducted using five scanning parameters i.e. film type, resolution, image bit depth, colour to grayscale transformation and image inversion. The results showed that increasing spatial resolution and deepening colour depth did not improve film sensitivity, while grayscale scanning caused sensitivity reduction below than that detected in the Red-channel. It is also evident that invert and colour negative film type selection negated netOD values, hence unsuitable for scanning RCFs. In conclusion, choosing appropriate scanning parameters are important to maintain preciseness and reproducibility in films dosimetry.