Download - Principle of Neurobioimaging 14 e
Principle of Neurobioimaging
Peni K Samsuria MutalibMedical Physics Department
Faculty of Medicine Universitas Indonesia
Goal
• Describe the principle of X-Ray, T-Ray, CT-scan, NMR (MRI), PET, STED
• (Principle of USG)
18961901
In 1901 Wilhelm Konrad Roentgen: the first recipient of the Nobel Prize for Physics
1896 his wife’s hand, he made the first X-ray photo, and thus, made it possible to look inside the human body without surgical intervention.
X-ray vs. T-ray!!droidmill.com
T-Ray
worldsfamousphotos.com
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There are 2 kind of Image• Anatomical (Gross)
– Tumor: Ventriculography,pneumoencephalography– Injury– Angiography
• Functional– Alzheimer STED 2014 Noble Prize– Cognitive psychology: Thought identification, Mind
reading (higher metabolism area & “light up” on scan
Brain CT with and without contrastSource: X-Ray
Without Contrast: directWith Contrast:• Only one CT contrast study
should be scheduled within a 48 hour period.
• BUN & Creatinine must be done within 72 hours of the scan.
• Nothing to eat, but clear liquid after midnight before the scan.
cedars-sinai.edu
CT scanning of the head is typically used to detect:
•Bone abnormalities •Brain mass/tumor •Fluid collection, such as an abcess •Hemorrhage •Hydrocephalus •Ischemic process, such as a stroke •Trauma or fracture of the skull
Look at the ventricles!
Normal CT
http://www.seattlechildrens.org/medical-conditions/brain-nervous-system-mental-conditions/hydrocephalus/
Brain CT!!Blood vessels: brightly w contrast
The bones are whiter than the surrounding area. (Whiter means higher attenuation.)
Blood vessels also brightly due to the injection of an iodine-based contrast agent. Displaced Ventricles in
Brain CT
Typical scan dosesExamination Typical effective dose
(mSv)(milli rem)
Chest X-ray 0.1 10
Head CT 1.5 150
Screening mammography 3 300
Abdomen CT 5.3 530
Chest CT 5.8 580
Chest, Abdomen and Pelvis CT 9.9 990
CT colonography (virtual colonoscopy)
3.6 - 8.8 360 - 880
Cardiac CT angiogram 6.7-13 670 - 1300
Barium enema 15 1500
Neonatal abdominal CT 20 2000
For comparison, survivors of the atomic bombings of Hiroshima and Nagasaki were exposed to an average of 40 mSv of radiation. This dose is comparable to 2-3 extensive CT scans, and can increase the risk of cancer.
Mod from Brenner NEJM rev 2007
Brain tumor MRI
With contrast
fMRI of the Brain
1. Magnetic resonance (MR) imaging uses radio waves and a strong magnetic field = NMR Nuclear Magnetic Resonance
2. Functional magnetic resonance imaging (fMRI) is used to measure metabolic changes in an active part of the brain (speech, sensation, memory, thought) etc.
3. Injuries and disease, such as stroke or brain tumor, cause functions to shift to other parts of the brain.
This 3 principles is used for planning surgery, radiation therapy, treatment for cerebral vascular or other interventions.
FMRI vs. fMRI?
The term "Functional MRI" (with a "capital F") can also include other MRI techniques that are sensitive to physiologic changes (such as changes in water motion)- EEG-PET.
FMRI identifying, investigating, and monitoring brain tumors, cerebral vascular, and certain chronic disorders (multiple sclerosis, dementia or seizures.
FMRI
And "little f" fMRI usually refers to mapping of brain activity using MRI.
fMRI studies are often used in planning brain surgery, since they can help physicians monitor normal brain function as well as any disturbed brain function (cerebral vascular, trauma, or degenerative disease (such as Alzheimer's) on brain function.
EEG MRI PET
FMRI: MRI & PET Brain
MRI, PET and CT scans of the brains of people affected by (clockwise from top left): Alcoholism, marijuana use, multiple sclerosis, cocaine use, Parkinson's disease, Alzehemier's disease.
11C contrast MRI & PET
Typical MRI and PET brain images of [11C]NNC112 (a) and [11C]FLB457 in the conscious MR images were (1.5 T). PET images were generated by summation of image data from 37 to 64 min after injection
FDG 18F Fluorodeoxyglucose (Fludeoxyglucose) make by cyclotron
18F-FDG or FDG
The meaning of:
What is Radio frequency, X-Ray and Gamma-ray?
• Geometrical Optics
• Physical Optics
• Quantum Optics
Electromagnetic wave spectrum: Radio waves!
(From Hopkins Ultraviolet Telescope Project, http://praxis.pha.jhu.edu/.)
Geometrical optics• Deals with those optical phenomena that are
mostly easily described with straight lines and plane geometry.
• Deals with macroscopic light
Physical optics• Dealing with the wave nature of light, • Deals with electromagnetic wave
Quantum optics• Dealing with quantum aspects of light, • Deals with particle (light as photon)
Optics
The experiments of all of the various known properties of light may be
grouped together and classified under one of the three following heads:
Geometrical Optics
Physical Optics Quantum Optics
Rectilinear propagation
Diffraction Photo-electric effect
Finite velocity Interference Compton effect
Reflection Polarization Atomic excitation
Refraction Double Refraction Pair production
X-ray and CT Scan: Absorption, Transmision Black-grey-white• 1895: Roentgen • 1900’s: Tomography (Y: tomos=slice)• 1970: CTScan (Computerized Tomography) X-ray or
CAT, PET 1975, MRI 1984• Nowadays imaging: CTScan, USG, MRI, PET, fMRI
USG BrainBaby’s brain USG Acranial & anencephaliy
Basic principle of Tomography• Collimated-X-raysbody
through the detector which measure the transmited intensity.
• Severals points was measured, while source and detector were move together pass through the body.
• This instrument is turned little surrounded the body’s axis and once again scanned; many times with interval (may be) 1o for 180o.
Rangkaian
detectors
X-ray source
CT Scan: source X-Ray
• Transmitted Intensity light from many points at any scan, and any angle, were sent to computer which reconstruct the slice image.
• Slice which will be imaging is cut to many small figure (pixel)
• Any pixel represent the intensity of the transmitted light and give a nuance of graded grey and e.g. image from elemen 100 x 100 for total 10 4 pixel ( 100 detector from 100 different angles.
Several mathematic reconstruction technique
• Iteration tech.
• Fourier transformation tech.
• Reverse projection tech. more directly
Nuclear Magnetic Resonance (NMR) = Magnetic Resonance Imaging
(MRI) of the Head
• Uses a magnetic field and pulses of radio wave energy for source. In many cases an MRI provides information that cannot be obtained from an X-ray, ultrasound, or CT scan.
• The MRI can also detect tissue damage or disease, such as infection, inflammation, or a tumor.
NMR/MRI for Medical Area (2003)
• MRS: Magnetic Resonance Spectroscopy for 1) determine the structure of unknown chemical stuff and 2) to study the binding characteristic of a known compound
• MRI: Magnetic Resonance Imaging to make a image af ‘slices organ
• NMR: Nuclear Magnetic Resonance is a basic of MRS dan MRI
MRI/NMR merupakan emmision (pemancaran/pencurahan) imaging
MRI
Patient in strength magnetic field (> 1.5 T) were given energy pulse short frequency of radio wave radio signal images which recorded from 3:
1) density of proton (H nucleus),
2) relaxation constant,
3) blood flow pattern (oxy vs. deoxy Hb)
MRI Use strong magnetic field •heart pacemaker •artificial heart valve•catheter •IUD •any metal plates, pins, screws or surgical staples•Tattoos •Eyeliner •Tooth fillings•Braces•hairpins, jewelry, eyeglasses,•hearing aids
Prepare the procedure!
Oxy vs. deoxy Hb
• The principle of fMRI imaging is to take a series of images of the brain in quick succession and to statistically analyze the images for differences among them.
• Oxy hemoglobin and deoxyhemoglobin are magnetically different is exploited. Oxy Hemoglobin shows up better on MRI images than deoxyhemoglobin; thus, oxygenated blood shows up better. Brain areas with more blood flow have been shown to have better visibility on MRI images (Cohen & Bookheimer, 1994)
correlated with brain activation• Other fMRI methods exploit the fact that the bulk movement of
hydrogen nuclei causes changes in the MRI image CSF flow, blood flow, or diffusion of water through tissue.
•When the frequency of the pulsed radio beam matches the frequency of the hydrogen atom, which induces the protons to flip, this is called the ‘Resonance Frequency’•Resonance in NMR is caused by the absorption of EM radiation in the radio frequency, by protons in magnetic field (Ho) which then flip. Flip only happen when the radio wave frequency is suitable. With strength Ho, the frequency must be more higher (E>)
•Flipped proton is also called resonanced proton
•When unflipped, there are E that emmited (signal for detector) computerized curve
Resonance proton: Flip & Relaxation [Absorption & Emmission]
Radio wave absorbed by nuclear atom (proton/H+)
• 1945: Proton through ‘nuclear spin’ absorb radio wave from suitable radio frequency while places in a strength magnetic field.
• The resonance frequency from nuclear atom is depends not only on: 1) magnetic power and 2) atomic type, but also on 3) chemical atom of the environment.
• ‘Nuclear spins’ from various nucleus could be interfere each other, produce fine structures that is sejumlah puncak dalam spektrum NMR
U Ssample
Radio frequence Generator
Radio frequence Detector
Main part of NMR spectrometer NMR
Jodoh tiap signal NMR dengan proton dalam makromolekul
• = ‘sequential assignment
1985 Wüthrich: Jarak antara sejumlah besar inti hidrogen dan memakai informasi ini dengan metode matematik bedasarkan geometri jarak untuk menghitung struktur 3D untuk molekul. Saat ini 15-20% dari ribuan struktur protein telah ditentukan dg NMR. Yg lain dg kristalografi sinar-X, beberapa dg difraksi elektron atau difraksi neutron
PET (Positron Emission Tomography)
• Radioactive
• Cyclotron to make Positron emitter
• Gamma detector
Positron a pair of gamma rays
• Positrons emitted by the nuclide annihilate with atomic electrons and emit a pair of gamma rays moving in opposite directions.
• the head is surrounded by gamma detectors, the delay between a gamma ray arriving on one side and its partner arriving opposite is used to calculate the position of the decay.
• In this way a map of decays taking place in the brain can be built up. If the subject is given different stimuli-music or speech for example-the pattern of blood flow in the brain changes
http://www.corbisimages.com/stock-photo/rights-managed/42-21818506/pet-scans-show-brains-response-to-musical
PET scans showing the varying rates of activity in different parts of the brains of three people listening too music indicates the greatest activity. The technique shows how untrained listeners react to music more with the right, intuitive hemisphere of the brain, white trained musicians rely on the left, logical side of the brain.
PET with musical stimulation
http://neurostudyclub.mcgill.ca/feb2004/feb2004_p6.htm
Anterior Speech Area on PET combined with MRI by Denise Klein & Brenda Milner
Music listener vs. maestro
PET scans showing the varying rates of activity in different parts of the brains of three peoples listening to musics. Red indicates the greatest activity. The technique shows how untrained listeners react to music more with the right, intuitive hemisphere of the brain, while trained musicians rely on the left, logical side of the brain.
The PET scanner
• PET is a technique that is revolutionizing research into the activity of the brain. A patient inhales CO containing some carbon-11 isotopes. CO is very good at attaching itself to haemoglobin molecules in red blood cells.
• When areas of the brain are active the blood flow to them increases, so the concentration of carbon-11 in that part of the brain increases. The 11C isotope of carbon is artificial and decays by β+ (positron) emission.
Detector-scintillation counter-photomultiplier tubes
• Within about 1 mm of its emission point a positron will annihilate with an electron to produce two gamma-ray photons. As the positrons are not moving that quickly when they annihilate with an electron, the two photons emerge virtually back-to back, which concerves momentum.
• The patient is surrounded by a ring of scintillation counters which detect the emerging gamma-ray photons (scintillation counters are photomultiplier tubes, each with its own sodium iodide crystals)
Record the activity, but..
• PET scan activity in the speech centre of the brain
• One disadvantage of the technique is that it cannot record the activity of parts of the brain that are constantly active – only changes in blood flow can be detected.
USG (ultrasonography)
• Not an electromagnetic wave
• A mechanical wave
• Reflection not transmission and emission
USG: Lower freq for deeper
2 64 108 1412 16 18MHz
Deeper structure
Superficial structure
Higher resolutionLower resolution
HIFU: 0,25-2 MHz
ESWL: 1-3 Hzprocoagulant5-12 MHz
USG for diagnosis is a reflection imaging
• Non-electromagnetic wave imaging
• Ultrasonic wave is reflected to body interface with difference acoustic impedance medium density and for x velocity use
Sound• Gelombang EM dengan frekuensi < frek cah • (f cah 4-7.5 x 10 14 Hz) = 4-7,5 x 10 –7 m (c=.f)• Jangkauan pendengaran manusia F audio 20-20.000 Hz
(satuan frek- 1Hz=1 siklus/det) (infrasonik< 20 Hz, ultrasonik > 20.000 Hz) Ultrasonik =/= supersonik ( v>vbunyi)
Jangkauan pendenganran orang tua < 10.000 Hz
Anjing: 50.000 Hz +, kelelawar 100.000 Hz +.
AM (Amplitudo Modulasi): 530-1600 kHz,
FM (Freq Modulasi) 88MHz & 108 MHz),
TV Amerika : 54& 88 MHz untuk kanal 2-6,
174 & 216 MHz untuk kanal 7-13,
470 890 MHz: untuk stasiun (UHF: Ultra High Frequency)
Untuk membahas gerak getaran perlu definisi
• Simpangan: jarak x massa dari titik seimbang pada setiap saat
• Amplitudo (A): simpangan maksimum• Siklus: gerak bolak balik yang lengkap dari titik
awal kemudian kembali ke titik yang sama• Periode (T): waktu yang dibutuhkan untuk 1
siklus lengkap (T tak tergantung A)• Frekuensi: jumlah siklus per detik
f
Af=1/T T=1/f Bila f= 5 siklus per detik;
T=1/5 detik
f
Ultrasound (frek > 20 kHz): tak bisa didengar & difraksi kecil (tak menyebar) shg bd > kecil dpt
dideteksi
Pantulan bunyi digunakan dalam banyak aplikasi untuk menentukan jarak Sonar atau teknik pulsa-gema digunakan untuk mencari (refleksi) atau memecah benda di bawah air (batu ginjal-interferensi).
Analisa gel yg terpantul dari berbagai struktur dan batas lapisan di dalam Bumi menghasilkan pola karakteristik yg berguna utk eksplorasi minyak dan mineral.
Dinding perut
Transduser Pulsa
Gema Gema
Tulang belakangK
ekua
tan
p uls
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Scan-A:
Waktu sebanding jarak rambatan
Scan-B:
Kecerahan=kekuatan sinyal
Waktu
USG menggantikan operasi pencarian dan prosedur lain yg
• Beresiko• Menyakitkan• Mahal
• Efek lain hingga saat ini – (sinar-x, laser, gelombang mikro berefek samping)
Difraksi (penyebaran) berkas sinar membatasi ketajaman citra
Cara bunyi terpantul =/= sinar x (digunakan dg prinsip abs, transmisi) CT Scan
Doppler Effects
Dg menggunakan pergeseran Doppler dari USG, digunakan utk mengukur velocity dlm tbh man, seperti aliran darah dan detak jantung janin
MCA : Middle Cerebral Artery in Transcranial Doppler
ARRS, 2004
STED Microscopy
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Lyman, Balmer, Paschen, Brackett, Pfund Series: Excitation-Emission
Nanocrystal Semiconductor
Invitrogen.com
Resonance pos & neg http://www.nature.com/srep/2013/130423/srep01707/fig_tab/srep01707_F1.html