SPI EXAM (100% Errorless solutions)

Harmonics correct answers multiples of the transducer frequency, created in tissues , twice the frequency. Work b/c fundamental beam undergoes distortion. Improve spatial resolution (inversion). Non linear behavior creates harmonics. - HARMONICS = higher frequencies than the indecent frequency (overtones) - micro bubbles generate stronger harmonic signals than tissue - RESULT: narrower beams, fewer side lobes, better contrast, better spatial resolution Head form correct answers Look at machine straight on Angle to hold transducer correct answers 30 degrees abduction ALARA correct answers As Low As Reasonably Achievable when the entire image is either too bright or too dark, changes in output power or receiver gain may correct the problem, always minimize pt exposure (acoustic power) coded excitation correct answers a way of processing the pulse to improve contrast resolution and reduce speckle a method of creating sound pulses carrying individual identity codes, identified and analyzed to improve image quality, takes place in the pulser, improves penetration and contrast resolution creates long sound pulses containing a wide range of frequencies contrast agents correct answers Gas bubbles encapsulated in a shell Injected into circulation and reflect strongly "light up" can pass through capillaries improve gray scale and doppler images and signal micro bubbles expand to a greater extent than they compress Patient care - What if pt asks about getting an abortion? correct answers We are not allowed to talk about or give recommendation on what to do, must refer to doctor Can sound travel through a vacuum? correct answers No. Sound must travel through matter and there is no matter in vacuums. scan converter correct answers AKA: Memory - stores information coming from receiver 2 methods - analog - real world digital - computer world spatial resolution correct answers Number of lines per frame the more pixels the better spatial resolution (detail of image) pixel density contrast resolution correct answers the ability to differentiate one shade of gray from another