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EJNMMI Research Aug 2023Several software tools have been developed for gated PET imaging that use distinct algorithms to analyze tracer uptake, myocardial perfusion, and left ventricle volumes...
BACKGROUND
Several software tools have been developed for gated PET imaging that use distinct algorithms to analyze tracer uptake, myocardial perfusion, and left ventricle volumes and function. Studies suggest that different software tools cannot be used interchangeably in humans. In this study, we sought to compare the left ventricular parameters in gated F-FDG PET/CT imaging in mice by three commercially available software tools: PMOD, MIM, and QGS.
METHODS AND RESULTS
Healthy mice underwent ECG-gated F-FDG imaging using a small-animal nanoPET/CT (Mediso) under isoflurane narcosis. Reconstructed gates PET images were subsequently analyzed in three different software tools, and cardiac volume and function (end-diastolic (EDV), end-systolic volumes (ESV), stroke volume (SV), and ejection fraction (EF)) were evaluated. While cardiac volumes correlated well between PMOD, MIM, and QGS, the left ventricular parameters and cardiac function differed in agreement using Bland-Altman analysis. EDV in PMOD vs. QGS: r = 0.85; p < 0.001, MIM vs. QGS: r = 0.92; p < 0.001, and MIM vs. PMOD: r = 0.88; p < 0.001, showed good correlations. Correlation was also found in ESV: PMOD vs. QGS: r = 0.48; p = 0.07, MIM vs QGS: r = 0.79; p < 0.001, and MIM vs. PMOD: r = 0.69; p < 0.01. SV showed good correlations in: PMOD vs. QGS: r = 0.73; p < 0.01, MIM vs. QGS: r = 0.86; p < 0.001, and MIM vs. PMOD: r = 0.92; p < 0.001. However, EF among correlated poorly: PMOD vs. QGS: r = -0.31; p = 0.26, MIM vs. QGS: r = 0.48; p = 0.07, and MIM vs. PMOD: r = 0.23; p = 0.41. Inter-class and intra-class correlation coefficient were > 0.9 underlining repeatability in using PMOD, MIM, and QGS for cardiac volume and function assessment.
CONCLUSIONS
All three commercially available software tools are feasible in small animal cardiac volume assessment in gated F-FDG PET/CT imaging. However, due to software-related differences in agreement analysis for cardiac volumes and function, PMOD, MIM, and QGS cannot be used interchangeably in murine research.
PubMed: 37572238
DOI: 10.1186/s13550-023-01026-w -
Radiotherapy and Oncology : Journal of... Sep 2023Gross tumor volume (GTV) changes during stereotactic ablative radiotherapy (SABR) for adrenal tumors are not well characterized. We studied treatment-induced GTV changes...
PURPOSE
Gross tumor volume (GTV) changes during stereotactic ablative radiotherapy (SABR) for adrenal tumors are not well characterized. We studied treatment-induced GTV changes during, and after, 5-fraction MR-guided SABR on a 0.35 T unit.
METHODS AND MATERIALS
Details of patients treated for adrenal metastases using 5-fraction adaptive MR-SABR were accessed. GTV changes between simulation and first fraction (ΔSF1) and all fractions were recorded. Wilcoxon paired tests were used for intrapatient comparisons. Logistic and linear regression models were used for features associated with dichotomous and continuous variables, respectively.
RESULTS
Once-daily fractions of 8 Gy or 10 Gy were delivered to 70 adrenal metastases. Median simulation-F1 interval was 13 days; F1-F5 interval was 13 days. Median baseline GTVs at simulation and F1 were 26.6 and 27.2 cc, respectively (p < 0.001). Mean ΔSF1 was + 9.1% (2.9 cc) relative to simulation; 47% of GTVs decreased in volume at F5 versus F1. GTV variations of ≥ 20% occurred in 59% treatments at some point between simulation to end SABR, and these did not correlate with baseline tumor characteristics. At a median follow-up of 20.3 months, a radiological complete response (CR) was seen in 23% of 64 evaluable patients. CR was associated with baseline GTV (p = 0.03) and ΔF1F5 (p = 0.03). Local relapses were seen in 6%.
CONCLUSION
Frequent changes in adrenal GTVs during 5-fraction SABR delivery support the use of on-couch adaptive replanning. The likelihood of a radiological CR correlates with the baseline GTV and intra-treatment GTV decline.
Topics: Humans; Tumor Burden; Neoplasm Recurrence, Local; Adrenal Gland Neoplasms; Magnetic Resonance Imaging; Adrenal Glands; Radiosurgery
PubMed: 37330058
DOI: 10.1016/j.radonc.2023.109749 -
Physics and Imaging in Radiation... Oct 2023Hippocampal-avoidance whole brain radiotherapy (HA-WBRT) can be a time-consuming process compared to conventional whole brain techniques, thus potentially limiting...
BACKGROUND AND PURPOSE
Hippocampal-avoidance whole brain radiotherapy (HA-WBRT) can be a time-consuming process compared to conventional whole brain techniques, thus potentially limiting widespread utilization. Therefore, we evaluated the clinical feasibility, via dose-volume metrics and timing, by leveraging a computed tomography (CT)-based commercial adaptive radiotherapy (ART) platform and workflow in order to create and deliver patient-specific, simulation-free HA-WBRT.
MATERIALS AND METHODS
Ten patients previously treated for central nervous system cancers with cone-beam computed tomography (CBCT) imaging were included in this study. The CBCT was the adaptive image-of-the-day to simulate first fraction on-board imaging. Initial contours defined on the MRI were rigidly matched to the CBCT. Online ART was used to create treatment plans at first fraction. Dose-volume metrics of these simulation-free plans were compared to standard-workflow HA-WBRT plans on each patient CT simulation dataset. Timing data for the adaptive planning sessions were recorded.
RESULTS
For all ten patients, simulation-free HA-WBRT plans were successfully created utilizing the online ART workflow and met all constraints. The median hippocampi D was 7.8 Gy (6.6-8.8 Gy) in the adaptive plan vs 8.1 Gy (7.7-8.4 Gy) in the standard workflow plan. All plans required adaptation at first fraction due to both a failing hippocampal constraint (6/10 adaptive fractions) and sub-optimal target coverage (6/10 adaptive fractions). Median time for the adaptive session was 45.2 min (34.0-53.8 min).
CONCLUSIONS
Simulation-free HA-WBRT, with commercially available systems, was clinically feasible via plan-quality metrics and timing, .
PubMed: 37772278
DOI: 10.1016/j.phro.2023.100491 -
Heliyon Apr 2024Non-alcoholic fatty liver disease (NAFLD) can lead to irreversible liver damage manifesting in systemic effects (e.g., elevated portal vein pressure and splenomegaly)...
Non-alcoholic fatty liver disease (NAFLD) can lead to irreversible liver damage manifesting in systemic effects (e.g., elevated portal vein pressure and splenomegaly) with increased risk of deadly outcomes. However, the association of spleen volume with NAFLD and related type 2-diabetes (T2D) is not fully understood. The UK Biobank contains comprehensive health-data of 500,000 participants, including clinical data and MR images of >40,000 individuals. The present study estimated the spleen volume of 37,066 participants through automated deep learning-based image segmentation of neck-to-knee MR images. The aim was to investigate the associations of spleen volume with NAFLD, T2D and liver fibrosis, while adjusting for natural confounders. The recent redefinition and new designation of NAFLD to metabolic dysfunction-associated steatotic liver disease (MASLD), promoted by major organisations of studies on liver disease, was not employed as introduced after the conduct of this study. The results showed that spleen volume decreased with age, correlated positively with body size and was smaller in females compared to males. Larger spleens were observed in subjects with NAFLD and T2D compared to controls. Spleen volume was also positively and independently associated with liver fat fraction, liver volume and the fibrosis-4 score, with notable volumetric increases already at low liver fat fractions and volumes, but not independently associated with T2D. These results suggest a link between spleen volume and NAFLD already at an early stage of the disease, potentially due to initial rise in portal vein pressure.
PubMed: 38665588
DOI: 10.1016/j.heliyon.2024.e28123 -
Survey of treatment and care practices in small-cell lung cancer among German radiation oncologists.Strahlentherapie Und Onkologie : Organ... Jul 2023The management of small-cell lung cancer shows differences, particularly with regard to the use of radio- (RT), chemo-, and immunotherapy. We performed a survey among...
BACKGROUND
The management of small-cell lung cancer shows differences, particularly with regard to the use of radio- (RT), chemo-, and immunotherapy. We performed a survey among German radiation oncologists to assess the management of small-cell lung cancer (SCLC).
METHODS
A 34-question online survey was created and sent out by e‑mail to radiation oncologists throughout Germany. The survey period extended from August 2020 to January 2021. The questions addressed indications for RT, planning techniques, dosing/fractionation, target volume definition for consolidative thoracic irradiation, and the use of prophylactic cranial irradiation (PCI). At the same time, we surveyed the use of atezolizumab. The survey addressed the treatment practice for limited-stage SCLC (LS-SCLC) and extensive-stage SCLC (ES-SCLC).
RESULTS
We received 74 responses. In LS-SCLC, treatment is planned predominantly based on diagnostic information from computed tomography (CT) of the thorax/abdomen/pelvis (88%), PET-CT (86%), and pulmonary function testing (88%). In LS-SCLC, 99% of respondents perform radiation concurrently with chemotherapy, preferably starting with cycle one or two (71%) of chemotherapy. The most common dose and fractionation schedule was 60-66 Gy in 30-33 fractions (once daily: 62% of all respondents). In ES-SCLC, 30 Gy in 10 fractions (once daily: 33% of all respondents) was the most commonly used regimen in consolidative thoracic irradiation. Only 25% use chemosensitization with RT. The inclusion criteria for PCI were similar for limited and extensive disease, with Karnofsky index (78% and 75%) being the most important decision factor. Respondents use a schedule of 30 Gy in 15 fractions most frequently in both stages (68% limited stage [LS], 60% extensive stage [ES]). Immunotherapy was used regularly or occasionally in LS-SCLC by 45% of respondents, with reduced lung function (37%), cardiac comorbidities (30%), and hepatic insufficiency (30%) being the most commonly mentioned exclusion criteria for this form of therapy. In ES-SCLC, atezolizumab use was reported in 78% of all questionnaires. Half of the respondents (49%) administer it simultaneously with cranial irradiation.
CONCLUSION
Our survey showed variability in the management of SCLC. Results from future studies might help to clarify open questions regarding the optimal treatment paradigms. In addition, new treatment modalities, such as immunotherapy, might change practices in the near future.
Topics: Humans; Lung Neoplasms; Radiation Oncologists; Positron Emission Tomography Computed Tomography; Small Cell Lung Carcinoma; Surveys and Questionnaires; Cranial Irradiation
PubMed: 36418442
DOI: 10.1007/s00066-022-02019-9 -
ACS Applied Polymer Materials Jan 2024Lightweight materials are highly desired in many engineering applications. A popular approach to obtain lightweight polymers is to prepare polymeric syntactic foams by...
Lightweight materials are highly desired in many engineering applications. A popular approach to obtain lightweight polymers is to prepare polymeric syntactic foams by dispersing hollow particles, such as hollow glass microbubbles (HGMs), in a polymer matrix. Integrating shape memory vitrimers (SMVs) in fabricating these syntactic foams enhances their appeal due to the multifunctionality of SMVs. The SMV-based syntactic foams have many potential applications, including actuators, insulators, and sandwich cores. However, there is a knowledge gap in understanding the effect of the HGM volume fraction on different material properties and behaviors. In this study, we prepared an SMV-based syntactic foam to investigate the influence of the HGM volume fractions on a broad set of properties. Four sample groups, containing 40, 50, 60, and 70% HGMs by volume, were tested and compared to a control pure SMV group. A series of analyses and various chemical, physical, mechanical, thermal, rheological, and functional experiments were conducted to explore the feasibility of ultralight foams. Notably, the effect of HGM volume fractions on the rheological properties was methodically evaluated. The self-healing capability of the syntactic foam was also assessed for healing at low and high temperatures. This study proves the viability of manufacturing multifunctional ultralightweight SMV-based syntactic foams, which are instrumental for designing ultralightweight engineering structures and devices.
PubMed: 38230367
DOI: 10.1021/acsapm.3c01749 -
Soft Matter Aug 2023The rheology of concentrated nanoemulsions is critical for their formulation in various applications, such as pharmaceuticals, foods, cosmetics, and templating advanced...
The rheology of concentrated nanoemulsions is critical for their formulation in various applications, such as pharmaceuticals, foods, cosmetics, and templating advanced materials. The rheological properties of nanoemulsions depend on interdroplet interactions, Laplace pressure, dispersed phase volume fraction, and continuous phase properties. The interdroplet forces can be tuned by background electrolytes (, charge screening), surfactant type, the excess surfactant micelle concentration, and depletant molecules such as polymer chains. In the current research, we study the effect of varying the content of poly(ethylene glycol)-diacrylate (PEGDA) on the interfacial tension of the water-oil phase and rheological properties of concentrated nanoemulsions with 50% and 60% volume fractions. Sodium dodecyl sulfate (SDS) is used as the ionic surfactant. The final concentrated nanoemulsions are repulsive according to overall interaction potentials and are in the glass and compressed states based on the effective volume fraction estimation. They contain nearly same SDS concentration on the droplet surface and also in the bulk, but a different amount of PEGDA. The scaled rheological properties of the glassy nanoemulsions show a higher dependency on the PEGDA content and the possible effect of polymer-surfactant complexations compared to those of the compressed ones. This dependency is more pronounced in small strain amplitudes but not in large strains in the non-linear regime. These results provide insights into formulating concentrated nanoemulsions with controlled rheology for expanded application areas.
PubMed: 37497795
DOI: 10.1039/d3sm00349c -
International Journal of Radiation... Jun 2024In this Pediatric Normal Tissue Effects in the Clinic (PENTEC) vision paper, challenges and opportunities in the assessment of subsequent neoplasms (SNs) from radiation... (Review)
Review
PURPOSE
In this Pediatric Normal Tissue Effects in the Clinic (PENTEC) vision paper, challenges and opportunities in the assessment of subsequent neoplasms (SNs) from radiation therapy (RT) are presented and discussed in the context of technology advancement.
METHODS AND MATERIALS
The paper discusses the current knowledge of SN risks associated with historic, contemporary, and future RT technologies. Opportunities for research and SN mitigation strategies in pediatric patients with cancer are reviewed.
RESULTS
Present experience with radiation carcinogenesis is from populations exposed during widely different scenarios. Knowledge gaps exist within clinical cohorts and follow-up; dose-response and volume effects; dose-rate and fractionation effects; radiation quality and proton/particle therapy; age considerations; susceptibility of specific tissues; and risks related to genetic predisposition. The biological mechanisms associated with local and patient-level risks are largely unknown.
CONCLUSIONS
Future cancer care is expected to involve several available RT technologies, necessitating evidence and strategies to assess the performance of competing treatments. It is essential to maximize the utilization of existing follow-up while planning for prospective data collection, including standardized registration of individual treatment information with linkage across patient databases.
Topics: Humans; Child; Cancer Survivors; Neoplasms, Radiation-Induced; Organs at Risk; Proton Therapy; Neoplasms, Second Primary; Dose-Response Relationship, Radiation; Dose Fractionation, Radiation; Age Factors; Adolescent; Radiotherapy; Genetic Predisposition to Disease; Neoplasms
PubMed: 38430101
DOI: 10.1016/j.ijrobp.2024.01.206 -
Microscopy Research and Technique Apr 2024The rabbit is widely used as a laboratory animal in experimental models of kidney diseases. This species is also important from a veterinary perspective as a companion...
The rabbit is widely used as a laboratory animal in experimental models of kidney diseases. This species is also important from a veterinary perspective as a companion animal. Stereology has been accepted as an accurate approach to kidney morphometry. The objective of the present project was to provide normal quantitative stereological parameters for adult rabbit kidneys. The left kidneys of five adult male New Zealand rabbits were used. Isotropic sections were obtained using the orientation method. Total kidney volume was calculated by the Cavalieri principle. The volume fraction of the renal structures was estimated using the point counting system. The lengths of the proximal convoluted tubule (PCT) and distal convoluted tubule (DCT) were calculated using counting frames. The total glomerular number was accounted for using the physical/fractionator technique. The mean glomerular volume was obtained by dividing the total volume of glomeruli by their total number. The total volume of rabbit kidneys calculated was 10.39 ± 1.98 cm. The fractional volume of the kidney cortex and medulla accounted for 57.79 ± 0.65% and 42.2 ± 0.65%, respectively. The total glomerular volume was 2.18 ± 0.32% of the whole kidney. The total number of glomeruli in the rabbit kidney was estimated as 204.68 ± 12 × 10. The mean glomerular volume measured 1.07 ± 0.12 × 10 μm. The total length of PCT and DCT was 2.96 ± 0.29 km and 1.38 ± 0.24 km, respectively. These findings can be used as a reference in experimental nephrology research and may help to expand the knowledge of nephrology in mammals by comparing with available data on humans and other species. RESEARCH HIGHLIGHTS: Three-dimensional morphometry of adult rabbit kidney structures was analyzed using quantitative stereology. Total volume of kidney, fractional volume of cortex and medulla, length of renal tubules and number of nephrons were estimated. These three-dimensional morphometrical data can be used as a reference in experimental nephrology research and may help to expand the knowledge of nephrology in mammals.
PubMed: 38655680
DOI: 10.1002/jemt.24578 -
Soft Matter Nov 2023The magnetic response of dynamic modulus was investigated for polyurethane-based magnetic elastomers densely packed with magnetic particles with different diameters (7...
The magnetic response of dynamic modulus was investigated for polyurethane-based magnetic elastomers densely packed with magnetic particles with different diameters (7 μm and 235 μm). The density indicated that voids were created at volume fractions of magnetic particles above 0.47 (87 wt%) for 7 μm and 0.44 (85 wt%) for 235 μm. At volume fractions below these critical volume fractions, no apparent increase in the storage modulus was observed for the magnetic elastomers by applying a magnetic field of 500 mT. At above the critical volume fractions, dramatic increase in the storage modulus was observed; the maximum changes in the storage modulus were 8.0 MPa and 6.0 MPa, which corresponds to the relative changes in the modulus (Δ/) of 74% and 11%, for magnetic elastomers of 7 μm and 235 μm, respectively. These results strongly indicate that the creation of a space enables the movement of magnetic particles in the elastomer resulting in the formation of chain structure. It was also found that the creation of a space in the matrix of elastomers can be detected by the critical strain, the amplitude of Payne effect, or the critical magnetic field since significant changes in these parameters were found at the critical volume fraction for both magnetic elastomers. SEM images displayed a clear difference in the creation process of voids that magnetic particles of 7 μm suddenly formed many macroscopic voids at the critical volume fraction, meanwhile, magnetic particles of 235 μm formed gaps around magnetic particles. The storage modulus for both magnetic elastomers changed perfectly in response to the magnetic field even after the on-off switching of the magnetic field with 20 cycles.
PubMed: 37830259
DOI: 10.1039/d3sm01061a