“Review” for Exam 2, BMEN 420 Medical Imaging 1. Bring your calculator 2. Remember that the exam is cumulative. Directly or indirectly, 10-15% of the material on this exam will relate to material on the first exam (examples: basic FT’s, blurring = convolution, …). I recommend going back to the review for exam 1 and take a look at those notes to be sure you still at least have some recollection of what they mean. 3. New material is in Chapters 6-11. Specifically, however, considering the following: a. Chapter 6 [CT] was covered with i. introductory powerpoint (electromagnetic point of view, basic ideas behind CT and reconstruction, generations of scanners) and with ii. lectures on image formation. iii. Hmwk 3 Summary: **Know and understand the Radon transform and the Projection Slice Theorem and reconstructing using the various techniques we covered.** The exam will certainly have a heavy weighting in this area since nearly all tomographic modalities employ some sort of similar reconstruction (this includes nuclear medicine and, at one point in history and sometimes still, MRI). Know and understand the various reconstruction equations given a set of projections. Have an understanding of the image quality issues in CT (primarily resolution and blurring) and how the imaging equation is affected (hint: it’s affected the same way it always is...). b. Chapters 7-9 [Nuclear Medicine] were covered very loosely with i. Introductory powerpoint (physics of NM, *similar relationship b/t projection radiography and CT and planar scintigraphy and SPECT*) ii. Notes packet/ homework 4. Note: you are not only responsible for blanks that you filled in or the questions you answered. You are responsible for the text in the entire package of notes to the extent that that is a reasonable expectation. Be reasonable in the amount of detail you study on this topic given how much it was covered in class. i.e. don’t focus on the details of the Anger Camera – just know that is the detection mechanism. Don’t memorize the imaging equation, but know what the components are and *what you are mapping*. c. Chapters 10-11 [Ultrasound] were covered with i. Introductory powerpoint (wave categories and basic ideas). Understand that all modes are based on A-mode scanning - the line of echoes that is shown in the powerpoint that is received by the transducer. A-mode scanning, sitting still, over time yields an M-mode scan. A-mode scanning over space yields a B-mode scan. There is a nice mode summary slide in the powerpoint. ii. lectures on 1. pressure/wave definitions 2. reflection a. assume λ small compared to interface → plane waves, reflectivity (what we want to reconstruct), transmittivity b. ĂƐƐƵŵĞʄ ůĂƌŐĞĐŽŵƉĂƌĞĚƚŽŝŶƚĞƌĨĂĐĞї ƐƉŚĞƌŝĐĂůǁ Ăǀ ĞƐ͕ ƐĐĂƩ ĞƌŝŶŐ͕ ƐƉĞĐŬůĞ 3. Attenuation & Absorption – strength of US signal is product of reflectivity and attenuation i. Example 10.5, modified slightly in notes ii. Depth of penetration 4. Beam geometry – Fresnel region/approximation (geometric region) and Fraunhofer region/approximation (both “simple” and “more accurate diffraction formulation”). Doesn’t it tie well into past information how the “more accurate” far field radiation pattern of a transducer is the FT of the transducer face? This is the form that all wave radiation in the far field takes…. 5. Imaging equation – just know that one exists and that it includes the blurring from the transducer “face” and modulation envelope of the pulse. In general, understand the reconstruction formulas as far as what the terms in the equations mean physically and what it is that we are mapping with the different modalities. Know where the modalities lie in the electromagnetic spectrum (if they rely on electromagnetic radiation). As always, feel free to email with specific questions.