Physics of magnetic resonance imaging This is a sub-article to Magnetic resonance imaging The human body is largely composed of water molecules, which each contain two hydrogen nuclei, or protons. When a person goes inside the powerful magnetic field (B0) of the scanner, the magnetic moments of these protons align with the direction of the field. Diseased tissue, such as tumors, can be detected because the protons in different tissues return to their equilibrium state at different rates (i.e., they have different T1 times). By changing the parameters on the scanner this effect is used to create contrast between different types of body tissue. Contrast agents may be injected intravenously to enhance the appearance of blood vessels, tumors or inflammation. MRI is used to image every part of the body, and is particularly useful for neurological conditions, for disorders of the muscles and joints, for evaluating tumors, and for showing abnormalities in the heart and blood vessels. Nuclear magnetism Imaging k-space
Seeing the light: Ed Boyden's tools for brain hackers This article was taken from the November 2012 issue of Wired magazine. Be the first to read Wired's articles in print before they're posted online, and get your hands on loads of additional content by subscribing online. Ed Boyden, an engineer turned neuroscientist, makes tools for brain hackers. In his lab at MIT, he's built a robot that can capture individual neurons and uses light potentially to control major diseases -- all in his quest to 'solve the brain'. To break into a neuron within a living brain, you need a good eye, extreme patience, months of training, and the ability to suck with gentle care. A mouse lies in front of you, brain exposed. An electrode in the pipette measures the resistance at its tip, and relays the signal to a monitor. If it works, you now have full access to the neuron's inner workings. Or at least you could if this technique, known as patch-clamping, were not so frustratingly hard. Boyden, 33, makes tools for brain hackers. But voyeurism is not enough.
Functional magnetic resonance imaging Researcher checking fMRI images Functional magnetic resonance imaging or functional MRI (fMRI) is a functional neuroimaging procedure using MRI technology that measures brain activity by detecting associated changes in blood flow. This technique relies on the fact that cerebral blood flow and neuronal activation are coupled. When an area of the brain is in use, blood flow to that region also increases. The primary form of fMRI uses the Blood-oxygen-level dependent (BOLD) contrast, discovered by Seiji Ogawa. The procedure is similar to MRI but uses the change in magnetization between oxygen-rich and oxygen-poor blood as its basic measure. FMRI is used both in the research world, and to a lesser extent, in the clinical world. Overview The fMRI concept builds on the earlier MRI scanning technology and the discovery of properties of oxygen-rich blood. History Three studies in 1992 were the first to explore using the BOLD contrast in humans. Physiology
Proton therapy Proton therapy is a type of particle therapy which uses a beam of protons to irradiate diseased tissue, most often in the treatment of cancer. The chief advantage of proton therapy is the ability to more precisely localize the radiation dosage when compared with other types of external beam radiotherapy, though it is controversial whether this provides an overall advantage compared to other, less expensive treatments. Description In a typical treatment plan for proton therapy, the Spread Out Bragg Peak (SOBP, dashed blue line), is the therapeutic radiation distribution. The SOBP is the sum of several individual Bragg peaks (thin blue lines) at staggered depths. Proton therapy is a type of external beam radiotherapy using ionizing radiation. To treat tumors at greater depths, the proton accelerator must produce a beam with higher energy, typically given in eV or electron volts. History Application In the case of prostate cancer the issue is not so clear. Surgery
Ωτοακουστικές Εκπομπές-Ακουστικά Προκλητά Δυναμικά-Ακουόγραμμα-Τυμπανόγραμμα Ωτοακουστικές εκπομπές «« Ακουστικά Προκλητά Δυναμικά «« Συχνές ερωτήσεις από τους γονείς (για νεογνά και βρέφη !) «« Φυσιολογική ακοή και ομιλία «« Το ντεσιμπέλ (dB) και η ένταση του ήχου «« Ποσοτική διάκριση της βαρηκοΐας «« Μονόπλευρη βαρηκοΐα «« Τυμπανόγραμμα «« Ακουόγραμμα «« Μαθησιακές δυσκολίες «« Ωτοακουστικές εκπομπές Πρόκειται για μία σύντομη, ανώδυνη και ασφαλή εξέταση. Εικ. 1 Φυσιολογική καταγραφή Παροδικά Προκλητών Ωτοακουστικών Εκπομπών σε νεογνό Εικ. 2 Μη καταγραφή ωτοακουστικών εκπομπών σε βρέφος με βαρηκοΐα Εικ. 3 Φυσιολογική καταγραφή ωτοακουστικών εκπομπών Προϊόντων Παραμόρφωσης Εικ. 4 Μη καταγραφή προϊόντων παραμόρφωσης σε παιδί με βαρηκοΐα Συνθήκες διεξαγωγής των Ωτοακουστικών Εκπομπών Προτιμούμε το παιδί να βρίσκεται σε κατάσταση ύπνου, αν και δεν είναι λίγες οι περιπτώσεις όπου διενεργούμε την εξέταση με το παιδί απλά ήρεμο στην αγκαλιά της μητέρας ή του πατέρα. Ακουστικά προκλητά δυναμικά Για τους ενήλικες. Aκουστικά προκλητά δυναμικά ASSR (Auditory Steady State Responses) 1.
MRI Physics The Basics MRIs make use of the unique property of atomic nuclei rotating in a strong magnetic field. These nuclei have a special "resonance" frequency that depends on the magnetic field. By absorbing radio waves of the same frequency, the nucleus' energy can be increased. Radio waves are re-emitted by the nuclei as they return to the lower energy state. The time it takes for the radio wave to do this is known as the ‘relaxation time’, and the different relaxation times result in varying bright and dark spots on the image. Before the MRI scanning process can begin, patients must remove all metal objects, such as jewellery or watches, because they may interfere with the magnetic field. Larmor Precession Nuclei have an intrinsic quantum property called spin. The spin is represented by the arrow. νL = γ * B where γ (the gyromagnetic ratio) for hydrogen is 42.58 MHz/T. The RF signal has a frequency equal to the unique resonant frequency of the nuclei, the Larmor frequency. A. A.
New Method for Intracellular Temperature Mapping A team of scientists from Japan has found a way to take a close look at the temperature distribution inside living cells. In a previous study, Dr Okabe’s team used a fluorescent polymeric thermometer and fluorescence lifetime imaging microscopy for intracellular temperature mapping. These images show temperature distribution in living COS7 cells. The team exploring the functions of mRNA – a molecule that encodes the chemical blueprint for protein synthesis – has been able to show the actual temperature inside living cells. Conventional temperature imaging methods lack spatial resolution and sensitivity, which means these methods are incapable of imaging extremely tiny temperature differences inside living cells. To overcome these issues, the scientists developed a new imaging method that combines a highly sensitive thermometer with an incredibly accurate detection technique, enabling the creation of detailed intracellular temperature maps.
Diffusion MRI Diffusion MRI (or dMRI) is a magnetic resonance imaging (MRI) method which came into existence in the mid-1980s. It allows the mapping of the diffusion process of molecules, mainly water, in biological tissues, in vivo and non-invasively. Molecular diffusion in tissues is not free, but reflects interactions with many obstacles, such as macromolecules, fibers, membranes, etc. Water molecule diffusion patterns can therefore reveal microscopic details about tissue architecture, either normal or in a diseased state. The first diffusion MRI images of the normal and diseased brain were made public in 1985. Since then, diffusion MRI, also referred to as diffusion tensor imaging or DTI (see section below) has been extraordinarily successful. Its main clinical application has been in the study and treatment of neurological disorders, especially for the management of patients with acute stroke. Diffusion Given the concentration and flux where D is the diffusion coefficient. .
North Metropolitan Health Service, Mental Health Role and Function North Metropolitan Health Service (NMHS) Mental Health aims to provide best practice, specialised mental health services supported by strategic planning in partnerships with service providers to the people of Western Australia. NMHS Mental Health is part of North Metropolitan Health Service which includes the Graylands, Sir Charles Gairdner, Osborne Park, Swan District and Kalamunda Hospitals and associated health services, Joondalup Health Campus and NMHS Population and Ambulatory Care Division. NMHS Mental Health is committed to the ongoing development and improvement of mental health services in Western Australia inline with relevant National and State policies, plans and frameworks. Services are delivered through inpatient units, community mental health centres, and day therapy and outreach programs to a catchment area of more than 800,000 people. NMHS Mental Health services are accessed by referral from a range of health care providers. Governance NMHS Vision Statement