Medical Imaging Exam 1 Version 1 Questions And Verified Answers Guaranteed Pass.

Types of medical imaging techniques - correct answer MRI, ultrasound, projection radiography (x-ray), CT, Nuclear (PET, SPECT) Projection - correct answer means losing 1 dimension of the image Tomographic - correct answer taking a slice of an organ Functional technique - correct answer shows function of the body Anatomical technique - correct answer shows the organs of the body What are the main medical imaging signals/mechanisms? - correct answer x-ray transmission, gamma ray emission, ultrasound echoes, NMR induction, speed of light in tissue How are CT and projection radiography similar? - correct answer they both selectively attenuate x-rays What is different between CT and projection radiography? - correct answer CT uses a beam of x-rays to take multiple projections around the to reconstruct a cross section of the body What type of technique is bone scan, planar scintigraphy? - correct answer projection What do the nuclear imaging techniques use to create an image? - correct answer use radioactive sources that emit radiation from the body What type of technique is PET, SPECT? - correct answer tomographic What is special about ultrasound image? - correct answer it has a color bar What is the MRI medical imaging technique? - correct answer uses high strength magnetic field and radio waves to image properties of the proton nucleus of a hydrogen atom What does an optical technique do? - correct answer uses light or near visible frequencies to image cells and tissues What are the transmission modalities? - correct answer CT and radiography What type of modality is nuclear medicine? - correct answer emission modality because the source of the signal is from inside the body What are the reflection modality? - correct answer optical and ultrasound Which techniques utilize the EM spectrum? - correct answer all of them except for ultrasound Where does MRI happen on the EM spectrum? - correct answer radiowaves, 10^6 Hz Where does ionizing radiation begin? - correct answer x-rays/gamma rays, 10^17 Hz What is required for imaging modalities to be successful? - correct answer correct contrast and imaging depth What portion of the EM spectrum is unused for medical imaging? - correct answer5 cm to .5 A Why is the portion of the electromagnetic spectrum with wavelengths between 5 cm and 0.5Å unused with regard to medical imaging? - correct answer Electromagnetic waves are attenuated by the conductive human body in a frequency-specific fashion. Too much attenuation results in low signal levels, but too little attenuation results in lack of tissue contrast. there is almost no transmission into the body in the range of wavelengths between 5 cm - 0.5 Å. Tomographic vs ultrasound - correct answer ultrasound is direct while tomographic gets raw data that needs to be analyzed What are all the projection modalities? - correct answer scintigraphy, projection radiography, PAM, bone scan What are all the tomographic modalities? - correct answer SPECT, PET, CT, MRI, OCT What are all the anatomic modalities? - correct answer projection radiography, CT, ultrasound, usually MRI, OCT What are all the functional modalities? - correct answer scintigraphy, SPECT, PET, What are all the ionizing modalities? - correct answer scintigraphy, SPECT, PET, projection radiography, CT What are all the non-ionizing modalities? - correct answer NMR and ultrasound What are all the types of nuclear medical imaging techniques? - correct answer PET, SPECT, scintigraphy What are the low resolution modalities? - correct answer scintigraphy, SPECT, ultrasound What are all the medium resolution modalities? - correct answer PET What are all the high resolution modalities? - correct answer projection radiography, CT, MRI Why are MRI and Ultrasound imaging considered "risk free", while the other modalities are not? - correct answer they do not use ionizing radiation; MRI uses 40-300 MHz electromagnetic waves while ultrasound uses 1-10 MHz sound waves What are the low cost imaging techniques? - correct answer radiography and ultrasound What is the most expensive imaging technique? - correct answer MRI What does non-invasive mean? - correct answer does not require the body to be cut open What are signals? - correct answer mathematical functions of one or more independent variables capable of of modeling physical processes What are systems? - correct answer produce an output from an original signal What are the different types of signals? - correct answer continuous, discrete, mixed What does a continuous function look like? - correct answer f(x,y) What does a discrete function look like? - correct answer g(m,n) What does a mixed signal function look? - correct answer g(l, theta) where l is continuous and theta is discrete (CT) What are all the signals of interest? - correct answer point impulse, line impulse, comb and sampling, rect and sinc, exponential/sinusoidal What does a point impulse tell you? - correct answer it good for characterizing a point source which shows how much a point is spread, which can be used for resolution purposes What is sifting? - correct answer realizing that the f(x) will only exist at the point where the impulse happens when you multiple f(x) by the delta and integrate What is a line impulse? - correct answer it is a bunch of point impulses on a line (continuous delta) line impulse - correct answer delta (xcos(theta)+ysin(theta)-l) What is l and theta in a line impulse? - correct answer the angle of the line impulse and l is how far from the origin it is What is sampling? - correct answer like sifting over a grid or matrix of points (picks of more points than a point impulse) Comb and sampling are __________ functions - correct answer discrete comb function - correct answer EE delta(x-m,y-n) Sampling function relation to comb function? - correct answer1/(∆x∆y) comb(x/∆x,y/∆y) When you ___________ in a comb, you have a sampling function - correct answer control the spacing What controls the spacing in the sampling function? - correct answer ∆x and ∆y Rect function - correct answer Hrect(x-m/X), y-n/Y) Sinc function - correct answer at x=y=0 the height is 1, where sin(pix)sin(piy)/(pi)^2xy everywhere else Rect relationship to sinc - correct answer fourier transform What is the equation for complex exponential? - correct answer e (x,y)= e^(j2pi(ux+vy))