33 research outputs found

    Shape Invariant Potential and Semi-Unitary Transformations (SUT) for Supersymmetric Harmonic Oscillator in T4-Space

    Full text link
    Constructing the Semi - Unitary Transformation (SUT) to obtain the supersymmetric partner Hamiltonians for a one dimensional harmonic oscillator, it has been shown that under this transformation the supersymmetric partner loses its ground state in T^{4}- space while its eigen functions constitute a complete orthonormal basis in a subspace of full Hilbert space. Keywords: Supersymmetry, Superluminal Transformations, Semi Unitary Transformations. PACS No: 14.80L

    Dosimetric Consequences of 3D Versus 4D PET/CT for Target Delineation of Lung Stereotactic Radiotherapy

    Get PDF
    Introduction:Lung tumor delineation is frequently performed using 3D positron emission tomography (PET)/computed tomography (CT), particularly in the radiotherapy treatment planning position, by generating an internal target volume (ITV) from the slow acquisition PET. We investigate the dosimetric consequences of stereotactic ablative body radiotherapy (SABR) planning on 3D PET/CT in comparison with gated (4D) PET/CT.Methods:In a prospective clinical trial, patients with lung metastases were prescribed 26 Gy single-fraction SABR to the covering isodose. Contemporaneous 3D PET/CT and 4D PET/CT was performed in the same patient position. An ITV was generated from each data set, with the planning target volume (PTV) being a 5-mm isotropic expansion. Dosimetric parameters from the SABR plan derived using the 3D volumes were evaluated against the same plan applied to 4D volumes.Results:Ten lung targets were evaluated. All 3D plans were successfully optimized to cover 99% of the PTV by the 26 Gy prescription. In all cases, the calculated dose delivered to the 4D target was less than the expected dose to the PTV based on 3D planning. Coverage of the 4D-PTV by the prescription isodose ranged from 74.48% to 98.58% (mean of 90.05%). The minimum dose to the 4D-ITV derived by the 3D treatment plan (mean = 93.11%) was significantly lower than the expected dose to ITV based on 3D PET/CT calculation (mean = 111.28%), p < 0.01. In all but one case, the planned prescription dose did not cover the 4D-PET/CT derived ITV.Conclusions:Target delineation using 3D PET/CT without additional respiratory compensation techniques results in significant target underdosing in the context of SABR

    Early immune pressure initiated by tissue-resident memory T cells sculpts tumor evolution in non-small cell lung cancer

    Get PDF
    Tissue-resident memory T (TRM) cells provide immune defense against local infection and can inhibit cancer progression. However, it is unclear to what extent chronic inflammation impacts TRM activation and whether TRM cells existing in tissues before tumor onset influence cancer evolution in humans. We performed deep profiling of healthy lungs and lung cancers in never-smokers (NSs) and ever-smokers (ESs), finding evidence of enhanced immunosurveillance by cells with a TRM-like phenotype in ES lungs. In preclinical models, tumor-specific or bystander TRM-like cells present prior to tumor onset boosted immune cell recruitment, causing tumor immune evasion through loss of MHC class I protein expression and resistance to immune checkpoint inhibitors. In humans, only tumors arising in ES patients underwent clonal immune evasion, unrelated to tobacco-associated mutagenic signatures or oncogenic drivers. These data demonstrate that enhanced TRM-like activity prior to tumor development shapes the evolution of tumor immunogenicity and can impact immunotherapy outcomes

    Comparative effectiveness of radial probe endobronchial ultrasound versus CT-guided needle biopsy for evaluation of peripheral pulmonary lesions: A randomized pragmatic trial

    Get PDF
    SummaryIn many patients the optimal method of investigation of peripheral pulmonary lesions (PPL) is not clear. We performed a prospective randomized pragmatic trial to determine the comparative effectiveness of endobronchial ultrasound-guided transbronchial lung biopsy (EBUS-TBLB) and CT-guided percutaneous needle biopsy (CT-PNB) for the investigation of PPL. Overall complication rates were higher in those undergoing CT-PNB (27% v 3%, p = 0.03), while diagnostic accuracy of EBUS-TBLB was shown to be non-inferior to that of CT-PNB.Expected diagnostic accuracy and complication rates are likely to differ for individual patients on the basis of specific complex clinicoradiologic factors, which will influence the cost-benefit analysis between EBUS-TBLB and CT-PNB for individual patients. Further studies are required to examine the effect of these factors on clinical decision-making

    Diagnostic enigma: primary pulmonary artery sarcoma

    No full text

    Systematic Endobronchial Ultrasound-guided Mediastinal Staging Versus Positron Emission Tomography for Comprehensive Mediastinal Staging in NSCLC Before Radical Radiotherapy of Non-small Cell Lung Cancer A Pilot Study

    Get PDF
    Despite known limitations of positron emission tomography (PET) for mediastinal staging of non-small cell lung cancer (NSCLC), radiation treatment fields are generally based on PET-identified disease extent. However, no studies have examined the accuracy of FDG-PET/CT on a per-node basis in patients being considered for curative-intent radiotherapy in NSCLC.In a prospective trial, patients with NSCLC being considered for definitive thoracic radiotherapy (± systemic chemotherapy) underwent minimally invasive systematic mediastinal evaluation with endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) following noninvasive staging with integrated PET-CT.Thirty patients underwent EBUS-TBNA, with TBNA performed from a mean 2.5 lymph node (LN) stations per patient (median 3, range 1-5). Discordant findings between PET-CT and EBUS-TBNA were observed in 10 patients (33%, 95% CI 19%-51%). PET-occult LN metastases were demonstrated by EBUS in 4 patients, whereas a lesser extent of mediastinal involvement, compared with FDG-PET, was demonstrated by EBUS in 6 patients, including 2 patients downstaged from cN3 to pN2. LNs upstaged by EBUS were significantly smaller than nodes downstaged by EBUS, 7.5 mm (range 7-9) versus 12 mm (range 6-21), P = 0.005.A significant proportion of patients considered for definitive radiotherapy (+/-chemotherapy) undergoing systematic mediastinal evaluation with EBUS-TBNA in this study have an extent of mediastinal NSCLC involvement discordant with that indicated by PET-CT. Systematic EBUS-TBNA may aid in defining the extent of mediastinal involvement in NSCLC patients undergoing radiotherapy. Systematic EBUS-TBNA has the potential to contribute significantly to radiotherapy planning and delivery, by either identifying occult nodal metastases, or demonstrating FDG-avid LNs to be disease-free

    Understanding factors influencing physical activity and exercise in lung cancer: a systematic review

    Get PDF
    PURPOSE: Despite evidence and clinical practice guidelines supporting physical activity (PA) for people with lung cancer, this evidence has not translated into clinical practice. This review aims to identify, evaluate and synthesise studies examining the barriers and enablers for patients with lung cancer to participate in PA from the perspective of patients, carers and health care providers (HCPs). METHODS: Systematic review of articles using electronic databases: MEDLINE (1950-2016), CINAHL (1982-2016), EMBASE (1980-2016), Scopus (2004-2016) and Cochrane (2016). Quantitative and qualitative studies, published in English in a peer-reviewed journal, which assessed the barriers or enablers to PA for patients with lung cancer were included. Registered-PROSPERO (CRD4201603341). RESULTS: Twenty-six studies (n = 9 cross-sectional, n = 4 case series, n = 11 qualitative) including 1074 patients, 23 carers and 169 HCPs were included. Barriers and enablers to PA were identified (6 major themes, 18 sub-themes): Barriers included patient-level factors (physical capability, symptoms, comorbidities, previous sedentary lifestyle, psychological influences, perceived relevance), HCP factors (time/knowledge to deliver information) and environmental factors (access to services, resources, timing relative to treatment). Enablers included anticipated benefits, opportunity for behaviour change and influences from HCPs and carers. CONCLUSION: This systematic review has identified the volume of literature demonstrating that barriers and enablers to PA in lung cancer are multidimensional and span diverse factors. These include patient-level factors, such as symptoms, comorbidities, sedentary lifestyle, mood and fear, and environmental factors. These factors should be considered to identify and develop suitable interventions and clinical services in attempt to increase PA in patients with lung cancer
    corecore