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1.
Sci Total Environ ; 781: 146573, 2021 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-33798876

RESUMO

Organic waste, the predominant component of global solid waste, has never been higher, resulting in increased landfilling, incineration, and open dumping that releases greenhouse gases and toxins that contribute to global warming and environmental pollution. The need to create and adopt sustainable closed-loop systems for waste reduction and valorization is critical. Using organic waste as a feedstock, gasification and pyrolysis systems can produce biooil, syngas, and thermal energy, while reducing waste mass by as much as 85-95% through conversion into biochar, a valuable byproduct with myriad uses from soil conditioning to bioremediation and carbon sequestration. Here, we present a novel case study detailing the circular economy of gasification biochar in Singapore's Gardens by the Bay. Biochar produced from horticultural waste within the Gardens was tested as a partial peat moss substitute in growing lettuce, pak choi, and pansy, and found to be a viable substitute for peat moss. At low percentages of 20-30% gasification biochar, fresh weight yields for lettuce and pak choi were comparable to or exceeded those of plants grown in pure peat moss. The biochar was also analyzed as a potential additive to concrete, with a 2% biochar mortar compound found to be of suitable strength for non-structural functions, such as sidewalks, ditches, and other civil applications. These results demonstrate the global potential of circular economies based on local biochar creation and on-site use through the valorization of horticultural waste via gasification, generating clean, renewable heat or electricity, and producing a carbon-neutral to -negative byproduct in the form of biochar. They also indicate the potential of scaled-up pyrolysis or gasification systems for a circular economy in waste management.

2.
Cells ; 10(3)2021 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-33800271

RESUMO

Mural cells collectively refer to the smooth muscle cells and pericytes of the vasculature. This heterogenous population of cells play a crucial role in the regulation of blood pressure, distribution, and the structural integrity of the vascular wall. As such, dysfunction of mural cells can lead to the pathogenesis and progression of a number of diseases pertaining to the vascular system. Cardiovascular diseases, particularly atherosclerosis, are perhaps the most well-described mural cell-centric case. For instance, atherosclerotic plaques are most often described as being composed of a proliferative smooth muscle cap accompanied by a necrotic core. More recently, the role of dysfunctional mural cells in neurodegenerative diseases, such as Alzheimer's and Parkinson's disease, is being recognized. In this review, we begin with an exploration of the mechanisms underlying atherosclerosis and neurodegenerative diseases, such as mural cell plasticity. Next, we highlight a selection of signaling pathways (PDGF, Notch and inflammatory signaling) that are conserved across both diseases. We propose that conserved mural cell signaling mechanisms can be exploited for the identification or development of dual-pronged therapeutics that impart both cardio- and neuroprotective qualities.

3.
Med Phys ; 2021 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-33843065

RESUMO

INTRODUCTION: Ultra-high dose rate (FLASH) radiotherapy has become a popular research topic with the potential to reduce normal tissue toxicities without losing the benefit of tumor control. The development of FLASH proton pencil beam scanning (PBS) delivery requires accurate dosimetry despite high beam currents with correspondingly high ionization densities in the monitoring chamber. In this study we characterized a newly designed high-resolution position sensing transmission ionization chamber with a purpose-built multi-channel electrometer for both conventional and FLASH dose rate proton radiotherapy. METHODS: The dosimetry and positioning accuracies of the ion chamber were fully characterized with a clinical scanning beam. On the FLASH proton beamline, the cyclotron output current reached up to 350 nA with a maximum energy of 226.2MeV, with 210±3 nA nozzle pencil beam current. The ion recombination effect was characterized under various bias voltages up to 1000 V and different beam intensities. The charge collected by the transmission ion chamber was compared with the measurements from a Faraday cup. RESULTS: Cross-calibrated with an Advanced Markus chamber (PTW, Freiburg, Germany) in a uniform PBS proton beam field at clinical beam setting, the ion chamber calibration was 38.0 and 36.7 GyE·mm2 /nC at 100 and 226.2 MeV, respectively. The ion recombination effect increased with larger cyclotron current at lower bias voltage while remaining ≤0.5±0.5% with ≥200 V of bias voltage. Above 200 V, the normalized ion chamber readings demonstrated good linearity with the mass stopping power in air for both clinical and FLASH beam intensities. The spot positioning accuracy was measured to be 0.10±0.08 mm in two orthogonal directions. CONCLUSION: We characterized a transmission ion chamber system under both conventional and FLASH beam current densities and demonstrated its suitability for use as a proton pencil beam dose and spot position delivery monitor under FLASH dose rate conditions.

4.
Clin Cancer Res ; 2021 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-33820781

RESUMO

PURPOSE: Chemo-radiotherapy for locally advanced cervical cancer fails in over a third of patients. Biomarkers with therapeutic implications are therefore needed. We investigated the relationship between an established prognostic marker, maximum standardized uptake value (SUVmax) on 18F-fluorodeoxyglucose positron emission tomography, and the inflammatory and immune state of cervical cancers. EXPERIMENTAL DESIGN: An SUVmax most prognostic for freedom from progression (FFP) was identified and compared to known prognostic clinical variables in a cohort of 318 patients treated with definitive radiation with prospectively collected clinical data. Gene set enrichment analysis (GSEA) and CIBERSORT of whole transcriptome data from 68 patients were used to identify biological pathways and immune cell subpopulations associated with high SUVmax-. Immunohistochemistry using a tissue microarray (TMA, N=82) was used to validate the CIBERSORT findings. The impact of macrophages on cervical cancer glucose metabolism was investigated in co-culture experiments. RESULTS: SUVmax <11.4 was most prognostic for FFP (p=0.001). The GSEA showed that high SUVmax is associated with increased gene expression of inflammatory pathways, including JAK/STAT3 signaling. CIBERSORT and CD68 staining of the TMA showed high SUVmax tumors are characterized by a monocyte-predominant immune infiltrate. Co-culture of cervical cancer cells with macrophages or macrophage-conditioned media altered glucose uptake, and IL-6 and JAK/STAT3 signaling contribute to this effect. CONCLUSIONS: SUVmax is a prognostic marker in cervical cancer that is associated with activation of inflammatory pathways and tumor infiltration of myeloid-derived immune cells, particularly macrophages. Macrophages contribute to changes in cervical cancer glucose metabolism.

5.
J Neurosci Res ; 2021 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-33789358

RESUMO

Traumatic brain injuries (TBIs) are common with an estimated 27.1 million cases per year. Approximately 80% of TBIs are categorized as mild TBI (mTBI) based on initial symptom presentation. While in most individuals, symptoms resolve within days to weeks, in some, symptoms become chronic. Advanced neuroimaging has the potential to characterize brain morphometric, microstructural, biochemical, and metabolic abnormalities following mTBI. However, translational studies are needed for the interpretation of neuroimaging findings in humans with respect to the underlying pathophysiological processes, and, ultimately, for developing novel and more targeted treatment options. In this review, we introduce the most commonly used animal models for the study of mTBI. We then summarize the neuroimaging findings in humans and animals after mTBI and, wherever applicable, the translational aspects of studies available today. Finally, we highlight the importance of translational approaches and outline future perspectives in the field of translational neuroimaging in mTBI.

6.
Cereb Cortex ; 2021 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-33676369

RESUMO

Younger age at first exposure (AFE) to repetitive head impacts while playing American football increases the risk for later-life neuropsychological symptoms and brain alterations. However, it is not known whether AFE is associated with cortical thickness in American football players. Sixty-three former professional National Football League players (55.5 ± 7.7 years) with cognitive, behavioral, and mood symptoms underwent neuroimaging and neuropsychological testing. First, the association between cortical thickness and AFE was tested. Second, the relationship between clusters of decreased cortical thickness and verbal and visual memory, and composite measures of mood/behavior and attention/psychomotor speed was assessed. AFE was positively correlated with cortical thickness in the right superior frontal cortex (cluster-wise P value [CWP] = 0.0006), the left parietal cortex (CWP = 0.0003), and the occipital cortices (right: CWP = 0.0023; left: CWP = 0.0008). A positive correlation was found between cortical thickness of the right superior frontal cortex and verbal memory (R = 0.333, P = 0.019), and the right occipital cortex and visual memory (R = 0.360, P = 0.012). In conclusion, our results suggest an association between younger AFE and decreased cortical thickness, which in turn is associated with worse neuropsychological performance. Furthermore, an association between younger AFE and signs of neurodegeneration later in life in symptomatic former American football players seems likely.

8.
Int J Med Sci ; 18(5): 1277-1284, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33526989

RESUMO

Rationale: To assess the longitudinal changes and relationships of clinical measures and extent of CT lung abnormalities in COVID-19. Methods: 81 patients with COVID-19 were prospectively enrolled and followed until discharge. CT scores were quantified on a basis of a CT scoring system where each lung was divided into 3 zones: upper (above the carina), middle, and lower (below the inferior pulmonary vein) zones; each zone was evaluated for percentage of lung involvement on a scale of 0-4 (0, 0%; 1, 0-24%; 2, 25% - 49%; 3, 50% -74%; 4, >74%).Temporal trends of CT scores and the laboratory parameters characteristic of COVID-19 were analyzed. Correlations between the two were determined at three milestones (initial presentation, worst CT manifestation, and recovery finding before discharge). Their correlations with duration to worst CT manifestation and discharge from symptom onset were evaluated. Results: CT scores peaked during illness days 6-11 (median: 5), and stayed steady. C-reactive protein and lactate dehydrogenase increased, peaked on illness days 6-8 and 8-11 (mean: 23.5 mg/L, 259.9 U/L), and gradually declined. Continual decrease and increase were observed in hemoglobin and lymphocyte count, respectively. Albumin reduced and remained at low levels with a nadir on illness days 12-15 (36.6 g/L). Both initial (r = 0.58, 0.64, p < 0.05) and worst CT scores (r = 0.47, 0.65, p < 0.05) were correlated with C-reactive protein and lactate dehydrogenase; and CT scores before discharge, only with albumin (r = -0.41, p < 0.05). Duration to worst CT manifestation was associated with initial and worst CT scores (r = 0.33, 0.29, p < 0.05). No parameters were related to timespan to discharge. Conclusion: Our results illustrated the temporal changes of characteristic clinical measures and extent of CT lung abnormalities in COVID-19. CT scores correlated with some important laboratory parameters, and might serve as prognostic factors.


Assuntos
/diagnóstico por imagem , Pulmão/diagnóstico por imagem , Adulto , Proteína C-Reativa/metabolismo , Feminino , Humanos , L-Lactato Desidrogenase/sangue , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Radiografia Torácica , Tomografia Computadorizada por Raios X
9.
J Child Neurol ; : 883073821991295, 2021 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-33557675

RESUMO

Succinic semialdehyde dehydrogenase (SSADH) deficiency is an autosomal recessive disorder of γ-aminobutyric acid (GABA) degradation, resulting in elevations of brain GABA and γ-hydroxybutyric acid (GHB). Previous magnetic resonance (MR) spectroscopy studies have shown increased levels of Glx in SSADH deficiency patients. Here in this work, we measure brain GABA in a large cohort of SSADH deficiency patients using advanced MR spectroscopy techniques that allow separation of GABA from overlapping metabolite peaks. We observed significant increases in GABA concentrations in SSADH deficiency patients for all 3 brain regions that were evaluated. Although GABA levels were higher in all 3 regions, each region had different patterns in terms of GABA changes with respect to age. We also report results from structural magnetic resonance imaging (MRI) of the same cohort compared with age-matched controls. We consistently observed signal hyperintensities in globus pallidus and cerebellar dentate nucleus.

10.
NMR Biomed ; : e4484, 2021 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-33559967

RESUMO

The translation of MRS to clinical practice has been impeded by the lack of technical standardization. There are multiple methods of acquisition, post-processing, and analysis whose details greatly impact the interpretation of the results. These details are often not fully reported, making it difficult to assess MRS studies on a standardized basis. This hampers the reviewing of manuscripts, limits the reproducibility of study results, and complicates meta-analysis of the literature. In this paper a consensus group of MRS experts provides minimum guidelines for the reporting of MRS methods and results, including the standardized description of MRS hardware, data acquisition, analysis, and quality assessment. This consensus statement describes each of these requirements in detail and includes a checklist to assist authors and journal reviewers and to provide a practical way for journal editors to ensure that MRS studies are reported in full.

11.
Brain Imaging Behav ; 15(2): 475-503, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33405096

RESUMO

Intimate partner violence includes psychological aggression, physical violence, sexual violence, and stalking from a current or former intimate partner. Past research suggests that exposure to intimate partner violence can impact cognitive and psychological functioning, as well as neurological outcomes. These seem to be compounded in those who suffer a brain injury as a result of trauma to the head, neck or body due to physical and/or sexual violence. However, our understanding of the neurobehavioral and neurobiological effects of head trauma in this population is limited due to factors including difficulty in accessing/recruiting participants, heterogeneity of samples, and premorbid and comorbid factors that impact outcomes. Thus, the goal of the Enhancing NeuroImaging Genetics through Meta-Analysis (ENIGMA) Consortium Intimate Partner Violence Working Group is to develop a global collaboration that includes researchers, clinicians, and other key community stakeholders. Participation in the working group can include collecting harmonized data, providing data for meta- and mega-analysis across sites, or stakeholder insight on key clinical research questions, promoting safety, participant recruitment and referral to support services. Further, to facilitate the mega-analysis of data across sites within the working group, we provide suggestions for behavioral surveys, cognitive tests, neuroimaging parameters, and genetics that could be used by investigators in the early stages of study design. We anticipate that the harmonization of measures across sites within the working group prior to data collection could increase the statistical power in characterizing how intimate partner violence-related head trauma impacts long-term physical, cognitive, and psychological health.

12.
Head Neck ; 43(1): 164-172, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32991009

RESUMO

BACKGROUND: Approximately 50% of patients with head and neck cancer (HNC) initially were seen with advanced disease. We aimed to evaluate the association of epidemiologic factors with advanced HNC at diagnosis. METHODS: The OraRad multicenter prospective cohort study enrolled HNC patients receiving curative-intent radiation therapy. Factors assessed for association with advanced HNC presentation at diagnosis included demographics, social and medical history, cancer characteristics, human papilloma virus (HPV) status, and dental disease measures. RESULTS: We enrolled 572 participants; 77% male and mean (SD) age of 61.7 (11.2) years. Oropharyngeal squamous cell carcinomas (88% HPV-related) were seen with smaller tumors, but more frequent nodal involvement. Private medical insurance and no Medicaid were associated with smaller tumors. A higher dental disease burden was associated with larger tumors. CONCLUSIONS: Insurance status, cancer type/location, and dental disease are associated with advanced HNC and may represent potentially modifiable factors or factors to be considered in the screening process of new lesions.

13.
Head Neck ; 43(4): 1128-1141, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33325579

RESUMO

BACKGROUND: Some patients with human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma (OPSCC) do not receive guideline-recommended postoperative radiation therapy (PORT) following primary transoral robotic surgery (TORS). METHODS: Three-hundred and sixty-four patients with treatment-naïve, HPV-associated OPSCC were recommended to receive PORT based on clinicopathological features following TORS. Patients were stratified based on if they received PORT. Oncologic outcomes were compared. RESULTS: The 3-year locoregional failure (LRF) was 32% in patients who did not receive PORT and 4% in patients who received PORT (P < .001). Despite increased LRF, avoiding PORT was not associated with increased 3-year distant metastasis rates (8% vs 4%, P = .56) or worse 3-year survival (95% vs 98%, P = .34). Recurrences in the surgery alone cohort varied between local and regional sites and were often successfully salvaged. CONCLUSIONS: Patients with HPV-associated OPSCC who do not receive indicated PORT have an increased risk of LRF but similar survival due to high salvage rates.

14.
Ann Surg Oncol ; 2020 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-33230747

RESUMO

BACKGROUND: Adjuvant radiation therapy (RT) can decrease lymph node basin (LNB) recurrences in patients with clinically evident melanoma lymph node (LN) metastases following lymphadenectomy, but its role in the era of modern systemic therapies (ST), immune checkpoint or BRAF/MEK inhibitors, is unclear. PATIENTS AND METHODS: Patients at four institutions who underwent lymphadenectomy (1/1/2010-12/31/2019) for clinically evident melanoma LN metastases and received neoadjuvant and/or adjuvant ST with RT, or ST alone, but met indications for RT, were identified. Comparisons were made between ST alone and ST/RT groups. The primary outcome was 3-year cumulative incidence (CI) of LNB recurrence. Secondary outcomes included 3-year incidences of in-transit/distant recurrence and survival estimates. RESULTS: Of 98 patients, 76 received ST alone and 22 received ST/RT. Median follow-up time for patients alive at last follow-up was 44.6 months. The ST/RT group had fewer inguinal node metastases (ST 36.8% versus ST/RT 9.1%; P = 0.04), and more extranodal extension (ST 50% versus ST/RT 77.3%; P = 0.02) and positive lymphadenectomy margins (ST 2.6% versus ST/RT 13.6%; P = 0.04). The 3-year CI of LNB recurrences was lower for the ST/RT group compared with the ST group (13.9% versus 25.2%), but this reduction was not statistically significant (P = 0.36). Groups did not differ significantly in in-transit/distant recurrences (P = 0.24), disease-free survival (P = 0.14), or melanoma-specific survival (P = 0.20). CONCLUSIONS: In the era of modern ST, RT may still have value in reducing LNB recurrences in melanoma with clinical LN metastases. Further research should focus on whether select patient populations derive benefit from combination therapy, and optimizing indications for RT following neoadjuvant ST.

15.
Radiother Oncol ; 155: 212-218, 2020 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-33186682

RESUMO

PURPOSE: Proton Pencil Beam Scanning (PBS) is an attractive solution to realize the advantageous normal tissue sparing elucidated from FLASH high dose rates. The mechanics of PBS spot delivery will impose limitations on the effective field dose rate for PBS. METHODS: This study incorporates measurements from clinical and FLASH research beams on uniform single energy and the spread-out Bragg Peak PBS fields to extrapolate the PBS dose rate to high cyclotron beam currents 350, 500, and 800 nA. The impact of the effective field dose rate from cyclotron current, spot spacing, slew time and field size were studied. RESULTS: When scanning magnet slew time and energy switching time are not considered, single energy effective field FLASH dose rate (≥40 Gy/s) can only be achieved with less than 4 × 4 cm2 fields when the cyclotron output current is above 500 nA. Slew time and energy switching time remain the limiting factors for achieving high effective dose rate of the field. The dose rate-time structures were obtained. The amount of the total dose delivered at the FLASH dose rate in single energy layer and volumetric field was also studied. CONCLUSION: It is demonstrated that while it is difficult to achieve FLASH dose rate for a large field or in a volume, local FLASH delivery to certain percentage of the total dose is possible. With further understanding of the FLASH radiobiological mechanism, this study could provide guidance to adapt current clinical multi-field proton PBS delivery practice for FLASH proton radiotherapy.

16.
Laryngoscope ; 2020 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-33098322

RESUMO

OBJECTIVES/HYPOTHESIS: Head and neck cancer (HNC) is the fifth most common malignancy in sub-Saharan Africa, a region with hyperendemic human immunodeficiency virus (HIV)-infection. HIV patients have higher rates of HNC, yet the effect of HIV-infection on oncologic outcomes and treatment toxicity is poorly characterized. STUDY DESIGN: Prospective observational cohort study. METHODS: HNC patients attending a government-funded oncology clinic in Botswana were prospectively enrolled in an observational cohort registry from 2015 to 2019. Clinical characteristics were analyzed via Cox proportional hazards and logistic regression followed by secondary analysis by HIV-status. Overall survival (OS) was evaluated via Kaplan-Meier. RESULTS: The study enrolled 149 patients with a median follow-up of 23 months. Patients presented with advanced disease (60% with T4-primaries), received limited treatment (19% chemotherapy, 8% surgery, 29% definitive radiation [RT]), and had delayed care (median time from diagnosis to RT of 2.5 months). Median OS was 36.2 months. Anemia was associated with worse survival (HR 2.74, P = .001). Grade ≥ 3 toxicity rate with RT was 30% and associated with mucosal subsite (OR 4.04, P = .03) and BMI < 20 kg/m2 (OR 6.04, P = .012). Forty percent of patients (n = 59) were HIV-infected; most (85%) were on antiretroviral therapy, had suppressed viral loads (90% with ≤400 copies/mL), and had immunocompetent CD4 counts (median 400 cells/mm3 ). HIV-status was not associated with decreased receipt or delays of definitive RT, worse survival, or increased toxicity. CONCLUSIONS: Despite access to government-funded care, HNC patients in Botswana present late and have delays in care, which likely contributes to suboptimal survival outcomes. While a disproportionate number has comorbid HIV infection, HIV-status does not adversely affect outcomes. LEVEL OF EVIDENCE: 2c Laryngoscope, 2020.

17.
Artigo em Inglês | MEDLINE | ID: mdl-33119091

RESUMO

Importance: While early epidemiologic studies ascribed increases in the incidence of human papillomavirus-associated oropharyngeal cancers to middle-aged patients, recent analyses have demonstrated an increasing median age of diagnosis. Treatment of patients older than 70 years is controversial as their inclusion in the practice-defining clinical trials has been limited and the survival benefit conferred by chemotherapy may be outweighed by treatment toxic effects. Objective: To assess the oncologic outcomes of older adults with human papillomavirus-associated oropharyngeal cancer who underwent upfront transoral robotic surgery and pathologic characteristics-guided adjuvant therapy in a large cohort of patients with close follow-up. Design, Setting, and Participants: A retrospective cohort analysis was conducted in a tertiary care academic medical center between January 1, 2010, and December 30, 2017. Patients aged 70 years or older at time of diagnosis with biopsy-proven and surgically resectable p16-positive oropharyngeal cancers were included. Data analysis was conducted from March 1 to June 1, 2020. Exposures: Transoral robotic surgery oropharyngeal resection and neck dissection with pathologic characteristic-guided adjuvant therapy. Main Outcomes and Measures: Three-year estimates of disease-specific survival, overall survival, and disease-free survival, as well as rates of adjuvant therapy (radiotherapy and chemoradiotherapy) and perioperative complications. Results: Seventy-seven patients were included (median age, 73.0; interquartile range, 71.0-76.0; range, 70-89 years); of these, 58 were men (75.3%). Perioperative mortality was 1.3% and the rate of oropharyngeal hemorrhage was 2.6%. Twenty-seven patients (35.1%) underwent postoperative radiotherapy and 20 patients (26.0%) underwent postoperative chemoradiotherapy. The median length of follow-up was 39.6 (range, 0.1-96.2) months, and the 3-year estimates of survival were 92.4% (95% CI, 82.4%-96.9%) for disease-specific survival, 90.0% (95% CI, 79.4%-95.0%) for overall survival, and 84.3% (95% CI, 73.4%-91.0%) for disease-free survival. Conclusions and Relevance: The findings of this cohort study suggest that transoral robotic surgery and pathologic characteristic-guided adjuvant therapy can provide beneficial survival outcomes, infrequent perioperative mortality, and, for most carefully selected older adults, obviate the need for chemotherapy.

18.
Br J Radiol ; 93(1116): 20190619, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32960655

RESUMO

OBJECTIVES: Prompt gamma (PG) imaging has previously been demonstrated for use in proton range verification of a brain treatment with a homogeneous target region. In this study, the feasibility of PG imaging to detect anatomic change within a heterogeneous region is presented. METHODS: A prompt gamma camera recorded several fractions of a patient treatment to the base of skull. An evaluation CT revealed a decrease in sinus cavity filling during the treatment course. Comparison of PG profiles between measurement and simulation was performed to investigate range variations between planned and measured pencil beam spot positions. RESULTS: For one field, an average over range of 3 mm due to the anatomic change could be detected for a subset of spots traversing the sinus cavity region. The two other fields appeared less impacted by the change but predicted range variations could not be detected. These results were partially consistent with the simulations of the evaluation CT. CONCLUSION: We report the first clinical application of PG imaging that detected some of the expected small regional proton range deviations due to anatomic change in a heterogeneous region. However, several limitations exist with the technology that may limit its sensitivity to detect range deviations in heterogeneous regions. ADVANCES IN KNOWLEDGE: We report on the first detection of range variations due to anatomic change in a heterogeneous region using PGI. The results confirm the feasibility of using PG-based range verification in highly heterogeneous target regions to identify deviations from the treatment plan.

19.
J Head Trauma Rehabil ; 35(5): 342-353, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32881768

RESUMO

OBJECTIVE: To evaluate the strength of associations between single-task and dual-task gait measures and posterior cingulate gyrus (PCG) neurochemicals in acutely concussed collegiate athletes. SETTING: Participants were recruited from an NCAA Division 1 University. PARTICIPANTS: Nineteen collegiate athletes acutely (<4 days) following sports-related concussion. DESIGN: We acquired magnetic resonance spectroscopy (MRS) in the PCG and gait performance measurements in the participants, acutely following concussion. Linear mixed-effects models were constructed to measure the effect of gait performance, in the single- and dual-task settings, and sex on the 6 neurochemicals quantified with MRS in mmol. Correlation coefficients were also calculated to determine the direction and strength of the relationship between MRS neurochemicals and gait performance, postconcussion symptom score, and number of previous concussions. MAIN MEASURES: Average gait speed, average cadence, N-acetyl aspartate, choline, myo-inositol, glutathione, glutamate plus glutamine, and creatine. RESULTS: Single-task gait speed (P = .0056) and cadence (P = .0065) had significant effects on myo-inositol concentrations in the PCG, independent of sex, in concussed collegiate athletes. Single-task cadence (P = .047) also had a significant effect on glutathione in the PCG. No significant effects were observed between dual-task gait performance and PCG neurochemistry. CONCLUSIONS: These findings indicate that increased concentrations of neuroinflammatory markers in the PCG are associated with slower single-task gait performance within 4 days of sports-related concussion.

20.
Brain Imaging Behav ; 2020 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-32797399

RESUMO

Proton (1H) magnetic resonance spectroscopy provides a non-invasive and quantitative measure of brain metabolites. Traumatic brain injury impacts cerebral metabolism and a number of research groups have successfully used this technique as a biomarker of injury and/or outcome in both pediatric and adult TBI populations. However, this technique is underutilized, with studies being performed primarily at centers with access to MR research support. In this paper we present a technical introduction to the acquisition and analysis of in vivo 1H magnetic resonance spectroscopy and review 1H magnetic resonance spectroscopy findings in different injury populations. In addition, we propose a basic 1H magnetic resonance spectroscopy data acquisition scheme (Supplemental Information) that can be added to any imaging protocol, regardless of clinical magnetic resonance platform. We outline a number of considerations for study design as a way of encouraging the use of 1H magnetic resonance spectroscopy in the study of traumatic brain injury, as well as recommendations to improve data harmonization across groups already using this technique.

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