Regulation of Skeletal Muscle Resistance Arteriolar Tone: Temporal Variability in Vascular Responses.

Introduction: A full understanding of the integration of the mechanisms of vascular tone regulation requires an interrogation of the temporal behavior of arterioles across vasoactive challenges. Building on previous work, the purpose of the present study was to start to interrogate the temporal nature of arteriolar tone regulation with physiological stimuli.

Methods: We determined the response rate of ex vivo proximal and in situ distal resistance arterioles when challenged by one-, two-, and three-parameter combinations of five major physiological stimuli (norepinephrine, intravascular pressure, oxygen, adenosine [metabolism], and intralumenal flow).

Multi-centre evaluation of variation in cumulative dose assessment in reirradiation scenarios.

Background And Purpose: Safe reirradiation relies on assessment of cumulative doses to organs at risk (OARs) across multiple treatments. Different clinical pathways can result in inconsistent estimates. Here, we quantified the consistency of cumulative dose to OARs across multi-centre clinical pathways.

Mind Over Magnets - How Magnetic Particle Imaging is Changing the Way We Think About the Future of Neuroscience.

Magnetic particle imaging (MPI) is an emerging imaging technique, which has the potential to provide the sensitivity, specificity and temporal resolution necessary for novel imaging advances in neurological applications. MPI relies on the detection of superparamagnetic iron-oxide nanoparticles, which allows for visualization and quantification of iron or iron-labeled cells throughout a subject. The combination of these qualities can be used to image many neurological conditions including cancer, inflammatory processes, vascular-related issues and could even focus on cell therapies and theranostics to treat these problems.

Evaluation of a 3-Dimensional-Printed Head Simulation Technique for Teaching Flexible Nasopharyngoscopy to Radiation Oncology Residents.

Purpose: Simulation-based medical education is an effective tool for medical teaching, but simulation-based medical education deployment in radiation oncology (RO) is limited. Flexible nasopharyngoscopy (FNP), an essential skill for RO residents, requires practice that typically occurs on volunteer patients, introducing the potential for stress and discomfort. We sought to develop a high-fidelity simulator and intervention that provides RO residents the opportunity to develop FNP skills in a low-pressure environment.

Radical radiotherapy for locally advanced non-small cell lung cancer-what's up with arm positioning?

Radical thoracic radiotherapy is ideally delivered in the arms-up (AU) position; however, patient comfort may only allow for arms-down (AD) positioning to be feasible. Objectives of this study were (I) to evaluate the dosimetric impact of changing arm position during treatment and (II) to compare plan quality for optimization in AU AD positions. In this retrospective planning study, stage III lung cancer patients (n=10) who received 60 Gy in 30 fractions using volumetric modulated arc therapy (VMAT) were identified.

NRF1 motif sequence-enriched genes involved in ER/PR -ve HER2 +ve breast cancer signaling pathways.

Nuclear respiratory factor 1 (NRF1) transcription factor has recently been shown to control breast cancer progression. However, mechanistic aspects by which NRF1 may contribute to susceptibility to different breast tumor subtypes are still not fully understood. Since transcriptional control of NRF1 seems to be dependent on epidermal growth factor receptor signaling, herein, we investigated the role of NRF1 in estrogen receptor/progesterone receptor negative, but human epidermal growth factor receptor 2-positive (ER/PR -ve HER2 +ve) breast cancer.

Half brain irradiation in a murine model of breast cancer brain metastasis: magnetic resonance imaging and histological assessments of dose-response.

Background: Brain metastasis is becoming increasingly prevalent in breast cancer due to improved extra-cranial disease control. With emerging availability of modern image-guided radiation platforms, mouse models of brain metastases and small animal magnetic resonance imaging (MRI), we examined brain metastases' responses from radiotherapy in the pre-clinical setting. In this study, we employed half brain irradiation to reduce inter-subject variability in metastases dose-response evaluations.

Image-guided radiation therapy for post-operative gynaecologic cancer: patient set up verification with and without implanted fiducial markers.

Background: Intensity modulated radiotherapy (IMRT) is increasingly being used to treat gynaecological malignancies in the postoperative setting. The purpose of this study was to evaluate the use of image-guided radiotherapy (IGRT) using cone-beam computed tomography (CBCT) with fiducial markers for daily localization.

Material And Methods: A single institution study was performed of consecutive cervical or endometrial cancer patients receiving adjuvant external beam radiotherapy (n = 15).

Stereotactic ablative radiotherapy for ultra-central lung tumors: prioritize target coverage or organs at risk?

Background: Lung stereotactic ablative radiotherapy (SABR) is associated with low morbidity, however there is an increased risk of treatment-related toxicity in tumors directly abutting or invading the proximal bronchial tree, termed 'ultra-central' tumors. As there is no consensus regarding the optimal radiotherapy treatment regimen for these tumors, we performed a modeling study to evaluate the trade-offs between predicted toxicity and local control for commonly used high-precision dose-fractionation regimens.

Methods: Ten patients with ultra-central lung tumors were identified from our institutional database.

MRI surveillance of cancer cell fate in a brain metastasis model after early radiotherapy.

Purpose: Incidence of brain metastasis attributed to breast cancer is increasing and prognosis is poor. It is thought that disseminated dormant cancer cells persist in metastatic organs and may evade treatments, thereby facilitating a mechanism for recurrence. Radiotherapy is used to treat brain metastases clinically, but assessment has been limited to macroscopic tumor volumes detectable by clinical imaging.

Cellular Imaging With MRI.

Cellular magnetic resonance imaging (MRI) is an evolving field of imaging with strong translational and research potential. The ability to detect, track, and quantify cells in vivo and over time allows for studying cellular events related to disease processes and may be used as a biomarker for decisions about treatments and for monitoring responses to treatments. In this review, we discuss methods for labeling cells, various applications for cellular MRI, the existing limitations, strategies to address these shortcomings, and clinical cellular MRI.

An enzyme-activatable and cell-permeable Mn-porphyrin as a highly efficient MRI contrast agent for cell labeling.

Magnetic resonance imaging (MRI) is a preferred technique for noninvasively monitoring the fate of implanted cells, such as stem cells and immune cells . Cellular MRI requires contrast agents (CAs) to label the cells of interest. Despite promising progress made in this emerging field, highly sensitive, stable and biocompatible CAs with high cell permeability and specificity remains an unmet challenge.

Evaluating Changes to Blood-Brain Barrier Integrity in Brain Metastasis over Time and after Radiation Treatment.

Introduction: The incidence of brain metastasis due to breast cancer is increasing, and prognosis is poor. Treatment is challenging because the blood-brain barrier (BBB) limits efficacy of systemic therapies. In this work, we develop a clinically relevant whole brain radiotherapy (WBRT) plan to investigate the impact of radiation on brain metastasis development and BBB permeability in a murine model.

Investigating the Impact of a Primary Tumor on Metastasis and Dormancy Using MRI: New Insights into the Mechanism of Concomitant Tumor Resistance.

Dormant cancer cells, also referred to as quiescent, slowly cycling or "nonproliferative" cells, are believed to contribute to tumor recurrence and present a therapeutic problem because they are nonresponsive to current therapies that target proliferating cells. Concomitant tumor resistance (CTR) is the ability of a primary tumor to restrict the growth of secondary metastases. In this paper, we investigate these 2 cancer concepts using cellular magnetic resonance imaging (MRI).

Understanding Heterogeneity and Permeability of Brain Metastases in Murine Models of HER2-Positive Breast Cancer Through Magnetic Resonance Imaging: Implications for Detection and Therapy.

Objectives: Brain metastases due to breast cancer are increasing, and the prognosis is poor. Lack of effective therapy is attributed to heterogeneity of breast cancers and their resulting metastases, as well as impermeability of the blood-brain barrier (BBB), which hinders delivery of therapeutics to the brain. This work investigates three experimental models of HER2+ breast cancer brain metastasis to better understand the inherent heterogeneity of the disease.

Brain metastases from breast cancer: lessons from experimental magnetic resonance imaging studies and clinical implications.

Breast cancer that has metastasized to the brain presents difficult clinical challenges. This diagnosis comes with high mortality rates, largely due to complexities in early detection and ineffective therapies associated with both dormancy and impermeability of the blood-brain barrier (BBB). Magnetic resonance imaging (MRI) is the current gold standard for diagnosis and assessment of brain tumors.