Introductory Biomedical Imaging

Course Materials

Lecture Notes

Lecture Notes

This page includes links to a complete set of lecture notes from Bethe Scalettar’s Spring 2026 Biomedical Imaging course. The notes were taken live by James Abney and recopied after class to improve legibility. The notes are organized chronologically, by lecture number. Each lecture was a full 60 minutes. The notes complement material in the book. They also should provide instructors with insight into how Bethe selects and presents material from the book. In 2026, Bethe began with microscopy (Chapters 2-8), followed up with medical imaging (Chapters 10-13), and finished with image processing and analysis (Chapter 9). Students were given a take-home midterm covering microscopy (lectures 1-23) and an in-class final covering medical imaging (lectures 24-37) and digital image processing (lectures 38 and 39). The amount of time spent on each subject, and the content of the corresponding lectures, varies somewhat from year-to-year, depending in part on class composition. For example, the class typically spends a lot of time on microscopy, especially fluorescence microscopy, because many of the students are biology majors working with those techniques. However, in years dominated by physics majors, the class has spent more time on underlying physics. Click on the lecture number to view the associated notes.

Lecture Date Key Words and Topics Chapter
11/21/26Course mechanics, overview of course subject matter1
21/23/26Light waves and rays, ray bending at interfaces, Snell’s law, lens function, ray diagrams2
31/26/26Image quality, geometrical optics versus wave optics, diffraction3
41/28/26Ray tracing, real and virtual images, minification and magnification, lens equations, Activity 13
51/30/26Simple microscope, ray diagram, eyepiece, objective, critical and Kohler illumination3
62/2/26Resolution, diffraction, Rayleigh theory, Activity 2, numerical aperture4
72/4/26Abbe theory (start)4
82/6/26Abbe theory (finish), Activity 3, introduction to contrast4,5
92/9/26Amplitude and phase specimens, brightfield microscopy, tricks to enhance contrast, Kohler ray trace, conjugate planes, Activity 4, darkfield microscopy (start)5
102/11/26Darkfield microscopy (finish), phase contrast microscopy (start)5
112/13/26Phase contrast microscopy (continued)5
122/16/26Phase contrast microscopy (finish), Activity 5, introduction to fluorescence, overview of fluorescence microscopy, Jablonski diagram5,6
132/18/26Fluorescence excitation and emission, photons, quantification of light energy6
142/20/26Excitation, emission, spectra, fluorescence microscope (light source, emission filter, dichromatic mirror, stage, emission filter, detector), Activity 6, multi-color imaging6
152/23/26Dichromatic mirrors for multi-color imaging, 3D imaging, optical sectioning, blur problem, introduction to confocal microscopy6
162/25/26Blur problem, point spread function (PSF), laser scanning confocal microscopy (LSCM), pinhole size6
172/27/26Spinning disk confocal microscopy (SDCM), Nipkow disk, camera, comparison of LSCM and SDCM6
183/2/26Widefield fluorescence microscopy, deconvolution, polarization microscopy, Activity 7, crossed polarizers5,6
193/4/26Specialized fluorescence techniques (overview), two-photon microscopy (start)7
203/6/26Two-photon microscopy (finish), total internal reflection fluorescence microscopy (TIRFM) (start)7
213/9/26Total internal reflection fluorescence microscopy (finish), super-resolution fluorescence microscopy (overview), structured illumination microscopy (SIM) (start), moiré patterns7,8
223/11/26Structured illumination microscopy (finish), beats, photoactivatable localization microscopy (PALM) (start)8
233/13/26Photoactivatable localization microscopy (finish), stimulated emission depletion (STED) microscopy8
243/16/26Activity 8 (Microscopy Review) – Problems 1-5
Ultrasound (start) – introduction (essence of ultrasound)
2-8
10
253/18/26Activity 8 (Microscopy Review) – Problems 6-11
Ultrasound (continued) – choice of US frequency, quantifying contrast, types of reflection (specular, diffuse, scattering), quantification of specular reflection
2-8
10
263/20/26Ultrasound (continued) – contrast, 13-microsecond rule, imaging modalities (A-Mode, M-Mode, B-Mode), resolution (lateral and axial) (start), Activity 910
273/30/26Ultrasound (continued) – resolution (finish), interplay between frequency and penetration depth, attenuation, time gain compensation (TGC)10
284/1/26Ultrasound (finish) – Doppler ultrasound
Radiography (start) – introduction (essence of radiography), diagnostic X-rays, basis of image formation, overview of imaging modes (projection vs. computed tomography)
10,11
294/3/26Radiography (continued) – interactions of X-rays with matter (photoelectric effect (good), Compton scattering (bad)), contrast agents, anti-scatter grids, local contrast (start), Activity 1011
304/6/26Radiography (continued) – local contrast (finish), Beer’s law, attenuation coefficients, resolution, computed tomography (CT) (start)11
314/8/26Radiography (finish) – CT (continued), single- vs multi-slice detectors, scanning modes, reconstruction algorithms, simple vs filtered back projection, Activity 11
Nuclear imaging (start) – comparison of X-ray and radionuclide imaging
11,12
324/13/26Nuclear imaging (continued) – nuclear instability, radioactivity, decay mechanisms, common radionuclides (e.g., Tc-99m and 18-fluorine), radioactive half-lives, projection imaging, collimators (start)12
334/15/26Nuclear imaging (continued) – collimators (finish), resolution, tomographic nuclear imaging (SPECT and PET) (start)12
344/17/26Nuclear imaging (finish) – tomographic nuclear imaging (SPECT and PET) (finish), time-of-flight (TOF) PET, iterative reconstruction, Activity 12
MRI (start) – brief introduction
12,13
354/20/26MRI (continued) – expanded introduction, nuclear magnetism, resonance (Larmor) frequency, slice selection (start)13
364/22/26MRI (continued) – slice selection (finish), Activity 13, phase encoding, frequency encoding13
374/24/26MRI (continued) – localization (recap), contrast (T1, T2, and density weighting) (start)13
384/27/26MRI (finish) – contrast (finish), Activity 14
Digital image processing (start) – analog vs digital signals, digitization, overview of restoration and enhancement
13,9
394/29/26Digital image processing (finish) – restoration scheme, brightness and contrast restoration (histogram stretching, lookup tables), gamma correction, noise reduction (mean and median filters), Fourier filters9