dr. zbigniew serafin, md, phd [email protected] · evacuated -path for the e s to travel through –...
TRANSCRIPT
The coursework of Radiology and Diagnostic Imaging includes 90 hours of tutorials and seminars. Tutorials
and seminars are prepared in a week cycle. The course is divided into Core Radiology on 4th year and Organ-
Based Radiology on 5th year. Core Radiology ends with a credit with grade. Organ-Based Radiology curriculum
ends with a final test exam. The final test will be timed in the schedule of the session.
Basic textbooks:
Gibson R: Essential Medical Imaging. Cambridge University Press, 2009.
Weissleder R: Primer of Diagnostic Imaging. 4th ed, Mosby Elsevier, 2007.
Moeller T.B., Reif E.: Pocket Atlas of Sectional Anatomy, Computed Tomography and Magnetic
Resonance Imaging, Vol. 1-3. Thieme Verlag, 2007.
Additional textbooks:
Daffner R: Clinical Radiology. Lippincott Williams & Wilkins, 2007.
Vilensky J: Medical Imaging of Normal and Pathologic Anatomy. WB Saunders Company, 2010.
Suetens P: Fundamentals of Medical Imaging, Cambridge University Press, 2009.
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Requirements and crediting
1. The classes are obligatory. In the case of the illness a sick leave has to be delivered. Other absences due to
important reason must be documented. In the case of the absence the respective topics have to be credited.
Students presenting with unjustified and uncredited absences will not be credited and allowed for the final
exam.
2. Each Student is obliged to come for the classes on time. Delayed Students can enter the class only if the
time of delaying does not exceed 15 minutes from the moment the classes have been started.
3. Students are obliged to prepare the respective part of the material for each classes. Topics are listed in
Syllabus. The knowledge and the activity of each Student will be noted. In the case of a negative note the
Student has to pass the respective topics till the end of the course.
4. Students are obligated to clean up after themselves. Eating, drinking, and using mobile phones during the
labs are prohibited. Any accidents, injuries and other emergencies must be immediately reported to the
Tutor.
5. Students are obliged to follow ethical rules as well as the rules of deontology, especially when attending live
cases.
6. Students are obliged to observe copyright and respect the right of intellectual property of electronic
publications as well as printed collections (published works, master’s and bachelor’s dissertations, course
books etc.) 3
Interim test
The test consists of multiple choice questions (only
one answer correct).
Students who failed the test are obliged to retake
the test.
The final scores of are not changeable.
The scores of the retake will be confirmed by a
signature in the Student Book as positive score but
not as the mean of these two.
In the case of an absence at the test a sick leave has
to be submitted to the examiner within three days
after the test.
The test will be assessed according to the following
scores:
Note Score
Unsatisfactory (2) < 60%
Satisfactory (3) 60-64%
Fairly Good (3,5) 65-69
Good (4) 70-79
Very Good (4,5) 80-89
Excellent (5) ≥ 90% 4
Plan of classes
seminars + exercises = 30 h
8:00 – 12:30
1. Monday – radiography.
2. Tuesday – computed tomography.
3. Wednesday – magnetic resonance imaging.
4. Thursday – ultrasonography.
5. Friday – management in radiology, TEST.
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Aims of classes
to provide basic knowledge on:
physical and technical principles of medical imaging,
cross-sectional anatomy,
indications and contraindications imaging,
radiation safety.
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Diagnostic imaging
radiography
fluoroscopy
invasive angiography
CT
MRI
ultrasound
nuclear imaging (scintigraphy, PET, SPECT)
coronarography, ventriculography, electrophysiology,
echocardiography
molecular imaging
optical iamging
interventional radiology
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organ-based approach
modality-based approach
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neuroimaging
cardiovascular imaging
MSK imaging
GI imaging
respiratory imaging
uroimaging
radiography
CT
MRI
ultrasound
nuclear imaging
interventional
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1895 – invention of X-rays by W.K. Roentgen
1895 – first X-ray of the human
1896 – first radiation in juries
1896 – Becquerel discovers radioactivity
1905 – the first English book on Chest Radiography is published
1918 – Eastman introduces radiographic film
1934 – Joliot and Curie discover artificial radionuclides
1950's – development of the image intensifier and X-ray television
1956 – medical use of ultrasound starts in Poland.
1962 – emission reconstruction tomography (later SPECT and PET)
1972 – invention of CT by Hounsfield at EMI
1977 – first human MRI images.
1980's – Fuji develops CR technology.
1984 – MRI cleared for commercial use by FDA
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November 8, 1895 Roentgen’s experimental apparatus (Crookes tube) that led to the discovery of the new radiation. Roentgen demonstrated that the radiation was not due to charged particles, but due to an as yet unknown source, hence “x” radiation or “x-rays.”
http://www.learningradiology.com 12
13 http://www.learningradiology.com
Bertha Roentgen (1895) „Über eine neue Art von Strahlen”
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Radiation
emission or emission and propagation of energy in the form of particles or waves.
Ionizing radiation
radiation having sufficient energy to ionize an atom
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Interaction of X-rays with matter = sources of attenuation
The attenuation that results due to the interaction between penetrating radiation and matter is not a simple process. A single interaction event between a primary x-ray photon and a particle of matter does not usually result in the photon changing to some other form of energy and effectively disappearing. Several interaction events are usually involved and the total attenuation is the sum of the attenuation due to different types of interactions.
These interactions include the photoelectric effect, scattering, and pair production
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Photoelectric absorption of x-rays occurs when the x-ray photon is absorbed, resulting in the ejection of electrons from the outer shell of the atom, and hence the ionization of the atom. Subsequently, the ionized atom returns to the neutral state with the emission of an x-ray characteristic of the atom. This subsequent emission of lower energy photons is generally absorbed and does not contribute to (or hinder) the image making process. Photoelectron absorption is the dominant process for x-ray absorption up to energies of about 500 KeV. Photoelectron absorption is also dominant for atoms of high atomic numbers.
Photoelectric effect is a low-energy phenomenon and is the most important for image acquisition and radiation safety
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Compton scattering occurs when the incident x-ray photon is deflected from its original path by an interaction with an electron. The electron gains energy and is ejected from its orbital position. The x-ray photon loses energy due to the interaction but continues to travel through the material along an altered path. Since the scattered x-ray photon has less energy, it, therefore, has a longer wavelength than the incident photon. The event is also known as incoherent scattering because the photon energy change resulting from an interaction is not always orderly and consistent.
Compton scattering is the most probable interaction of gamma rays and high energy X-rays with atoms in living beings. The phenomenon responds for the image noise and health hazard related to imaging.
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Thomson scattering (Rayleigh, coherent, or classical scattering), occurs when the x-ray photon interacts with the whole atom so that the photon is scattered with no change in internal energy to the scattering atom, nor to the x-ray photon. Thomson scattering is never more than a minor contributor to the absorption coefficient. The scattering occurs without the loss of energy. Scattering is mainly in the forward direction.
Thomson scattering is related to 5-10% of all tissue interactions with X-rays.
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Pair production can occur when the x-ray photon energy is greater than 1.02 MeV, but really only becomes significant at energies around 10 MeV. Pair production occurs when an electron and positron are created with the annihilation of the x-ray photon. Positrons are very short lived and disappear (positron annihilation) with the formation of two photons of 0.51 MeV energy. Pair production is of particular importance when high-energy photons pass through materials of a high atomic number.
Pair production is used in PET imaging.
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Basic X-ray production
electron source – cathode
target – anode
evacuated path for the e-s to travel through – x-ray tube insert
external energy source to accelerate the e-s – generator
X-rays are produced when energetic electrons strike a metal target. The X-ray source consists of an evacuated tube containing a cathode, from which the electrons are emitted, and an anode, which supports the target material where the X-rays are produced. Only about 1 per cent of the energy used is emitted as X-rays – the remainder is dissipated as heat in the anode. In most systems the anode is rotated so that the electrons strike only a small portion at any one time and the rest of the anode can cool. The X-rays are emitted from the tube via a radio-translucent exit window.
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Electron interactions with the anode produce:
1. Heat – the kinetic energy (KE) of the electron deposits its energy in the form of heat (~99%)
2. X-rays production
Bremsstrahlung
– continuous energy spectrum
characteristic X-rays – discrete energies
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Each part of the X-ray tube is essential to create the environment necessary to produce x-rays via:
Bremsstrahlung
Characteristic x-rays
The potential difference (kVp), tube current (mA), and exposure time (s) are selectable parameters to determine the x-ray spectrum characteristics (quality and quantity of x-ray photons
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X-ray tube filtration:
absorbs low-energy x-rays
inherent filtration - glass or metal insert at x-ray tube window
added filtration (Al, Cu, plastic, Mo, Rh)
reduces patient dose
increases x-ray beam quality
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X-ray tube collimation:
collimators adjust size and shape of x-ray beam
reduces patient dose
improves image contrast
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Other elements of X-ray tube:
HF generator – converts AC to DC and increases the voltage
operator console – exposure time settings
phototimers – AEC system
Bucky grid
patient’s table
detector
80 kW generator can produce 800 mA at 100 kVp
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Other elements of X-ray tube:
HF generator – converts AC to DC and increases the voltage
operator console – exposure time settings
phototimers – AEC system
Bucky grid
patient’s table
detector
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Other elements of X-ray tube:
HF generator – converts AC to DC and increases the voltage
operator console – exposure time settings
phototimers – AEC system
Bucky grid
patient’s table
detector (casette)
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Limitations of film-screen radiography:
limited dynamic range (only about two orders of magnitude)
difficult multiplication of the image
waiting time for the result
limited processing capabilities
need for additional personnel
environmental pollution
QA monitoring is time consuming
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Digital radiography:
Computed Radiography (CR)
phosphor-based storage plate
chemical storage (oxidation of Eu)
laser scanning, light erasure
Digital Radiography (DR)
flat-panel detectors
Csl scintillator and photo-diodes
better dynamic range, quantum efficiency
Charge Coupled Device (CCD)
phosphor screen, fiberoptic cables, CCD sensor
good sensitivity, low noise
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What can we imagine on plain films?
skeleton
high-density foreign bodies
calcifications
tubular structures
EXERCISE
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What can we imagine on plain films?
skeleton
high-density foreign bodies
calcifications
tubular structures
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What can we imagine on plain films?
skeleton
high-density foreign bodies
calcifications
tubular structures
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What can we imagine on plain films?
skeleton
high-density foreign bodies
calcifications
tubular structures
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What can we imagine on plain films?
skeleton
high-density foreign bodies
calcifications
tubular structures
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congenital
trauma
inflammation
neoplasms
cardiovascular
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congenital
trauma
inflammation
neoplasms
cardiovascular
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congenital
trauma
inflammation
neoplasms
cardiovascular
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congenital
trauma
inflammation
neoplasms
cardiovascular
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congenital
trauma
inflammation
neoplasms
cardiovascular
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CNS
skeleton
cardiovascular
respiratory
GI
urinary
reproductive
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CNS
skeleton
cardiovascular
respiratory
GI
urinary
reproductive
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CNS
skeleton
cardiovascular
respiratory
GI
urinary
reproductive
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CNS
skeleton
cardiovascular
respiratory
GI
urinary
reproductive
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CNS
skeleton
cardiovascular
respiratory
GI
urinary
reproductive
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CNS
skeleton
cardiovascular
respiratory
GI
urinary
reproductive
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CNS
skeleton
cardiovascular
respiratory
GI
urinary
reproductive
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???
infertility
neoplasms
cataracts (progressive lens opacity)
heritable mutations
marrow stimulation / depletion
contrast media
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???
pregnancy
ataxia teleangiectasia
Bloom syndrome
clinically unstable patient
obesity
lacking indications!!!
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???
infertility
neoplasms
cataracts (progressive lens opacity)
heritable mutations
marrow stimulation / depletion
contrast media
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???
infertility
neoplasms
cataracts (progressive lens opacity)
heritable mutations
marrow stimulation / depletion
contrast media
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Any substance that renders an organ or structure more visible than is possible without its addition. CM allows visualization of structures that can not be seen well or at all under normal circumstances
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Contrast media is needed because:
Soft tissue has a low absorption / interaction ratio
Absorption is dependent on
• atomic number
• atomic density
• electron density
• part thickness
• K-shell binding energy (K-edge)
Negative CM
air
oxygen
carbon dioxide
Positive CM
barium
iodine
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Non-water-soluble CM
absorbed – oily &/or viscous (Lipiodol)
not absorbed – inert (Barium)
Water-soluble
non-injectible – oral
injectible – intravenous
Direct application
barium studies
angiography
Water-soluble
non-injectible – oral
injectible – intravenous
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Adverse reactions:
anaphylactoid • urticaria • facial / laryngeal edema • bronchospasm • circulatory collapse
non-anaphylactoid • nausea / vomiting • cardiac arrhythmia • pulmonary edema • seizure • renal failure
delayed • fever, chills, rush • nausea, vomiting • headache
DEATH:
1/40.000 – 1/200.000 patients
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Clinical applications:
vascular imaging
inflammation
neoplasms
GI tract imaging
urinary tract imaging
trauma
„tissue differentiation”
59 http://www.learningradiology.com
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Flat-panel detector
Clinical applications:
GI tract imaging intraoperative image-guidance evacuation of foreign bodies differentiation of pulmonary nodules ERCP --------------------
62 http://www.learningradiology.com
Whose that hand? (1896) lime / mercury / petroleum
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Digital Subtracted Angiography (DSA)
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Digital Subtracted Angiography (DSA)
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Digital Subtracted Angiography (DSA)
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Additional processing features of DSA
last image hold road mapping pixel shifting 3D DSA
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Clinical applications:
vascular imaging
• arteriography
• venography
• lymphography ?
(endovascular procedures – interventional radiology)
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arteriography
vascular malformations
atherosclerosis
embolism
trauma
neoplasms
fistulae
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arteriography
vascular malformations
atherosclerosis
embolism
trauma
neoplasms
fistulae
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arteriography
vascular malformations
atherosclerosis
embolism
trauma
neoplasms
fistulae
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arteriography
vascular malformations
atherosclerosis
embolism
trauma
neoplasms
fistulae
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arteriography
vascular malformations
atherosclerosis
embolism
trauma
neoplasms
fistulae
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arteriography
vascular malformations
atherosclerosis
embolism
trauma
neoplasms
fistulae
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venography
deep vein thrombosis
pulmonary embolism
vascular malformations
vein insufficiency
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venography
deep vein thrombosis
pulmonary embolism
vascular malformations
vein insufficiency
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venography
deep vein thrombosis
pulmonary embolism
vascular malformations
vein insufficiency
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venography
deep vein thrombosis
pulmonary embolism
vascular malformations
vein insufficiency
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phlebography
lymphatic edema
metastases
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previous severe reaction to contrast media
impaired blood clotting factors
inability to undergo surgical procedure
impaired renal function ?
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puncture site
infection hematoma nerve injury (brachial plexus)
arteriography
vasospasm dissection, stenosis, occlusion perforation, hemorrhage release of atheroma, embolism stroke, AKI, mesenteric ischemia, limb ischemia DEATH
venography
phlebitis, thrombophlebitis dislodging a clot, embolism
contrast media
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