Medical physics (A-level only) – A Level AQA Physics revision notes
Choose a subtopic. Medical physics (A-level only) covers Physics of the eye (A-level only), Physics of the ear (A-level only), Biological measurement (A-level only), and Non-ionising imaging (A-level only) in A Level AQA Physics. 34 lessons in 6 subtopics.
Revise Medical physics (A-level only) for A Level AQA Physics, including Physics of the eye (A-level only) and Physics of the ear (A-level only).
34
Lessons
6
Subtopics
What this topic covers
Medical physics (A-level only) has 6 subtopics:
Physics of the eye (A-level only)
Physics of the ear (A-level only)
Biological measurement (A-level only)
Non-ionising imaging (A-level only)
X-ray imaging (A-level only)
Radionuclide imaging and therapy (A-level only)
Medical physics (A-level only) lessons by subtopic
Converging and Diverging Lenses: Explore the properties of converging and diverging lenses, including principal focus, focal length, and power. Also, understand how to use the lens equation and magnification formula.
Common Eye Defects: Learn about common eye defects such as myopia, hypermetropia, and astigmatism.
Correcting Eye Defects: Understand how lenses correct myopia and hypermetropia, including ray diagrams and power calculations. Also, learn about prescriptions for astigmatism.
Sound Intensity and the Decibel Scale: Learn about the definition of intensity, how to calculate intensity level using the decibel scale, and explore relative intensity levels of common sounds.
Noise Damage and Age-Related Hearing Loss: Explore how noise exposure and aging impact hearing, focusing on changes to equal loudness curves and perceived hearing loss.
Understanding ECG Waveforms: Explore the principles behind ECG machines and learn to interpret a normal ECG waveform.
Non-ionising imaging (A-level only)
Ultrasound Principles: Acoustic Impedance and Wave Behaviour: Explore the fundamental principles of ultrasound imaging, focusing on acoustic impedance, reflection, transmission, and attenuation of sound waves at tissue boundaries. Learn to apply the relevant equations to calculate reflection coefficients.
Generating and Detecting Ultrasound Pulses: Understand the principles behind the generation and detection of ultrasound pulses using piezoelectric devices. Compare A-scans and B-scans, and investigate the advantages, disadvantages and safety issues of ultrasound imaging.
Fibre Optics in Medical Physics: Explore the properties of fibre optics, including total internal reflection, and their application in medical physics.
Endoscopes: Principles and Applications: Understand the physical principles behind flexible endoscopes, the use of coherent and non-coherent fibre bundles, and examples of their use for internal imaging.
MRI: Alignment and Precession: Explore how protons align in a magnetic field and begin to precess, setting the stage for MRI scanning.
MRI: Excitation, Detection, and Imaging: Investigate the use of gradient coils and RF pulses to excite protons, the detection of emitted signals, and the creation of a visual image.
X-ray imaging (A-level only)
X-ray Attenuation: An introduction to the exponential attenuation of X-rays, including the linear and mass attenuation coefficients.
CT Scanner Principles: Explore the key principles of a CT scanner including X-ray tube movement, beam characteristics, detector arrays and computer processing to create visual images.
X-ray Production and Energy Spectrum: Explore the physical principles behind X-ray production, including the continuous and characteristic spectrum, and understand the factors influencing maximum photon energy.
X-ray Tube Design and Image Control: Understand the design of a rotating-anode X-ray tube and methods for controlling beam intensity, photon energy, image sharpness, contrast, and patient dose.
Contrast Enhancement and Photographic Methods: Understand contrast enhancement techniques using X-ray opaque materials and explore photographic detection with intensifying screens and fluoroscopic image intensification.
Radionuclide imaging and therapy (A-level only)
High-Energy X-Ray Therapy: An introduction to external radiotherapy using high-energy X-rays, focusing on methods to minimise exposure to healthy cells.
Beta Emitting Implants for Internal Treatment: An introduction to the use of beta emitting radioactive implants for internal treatment, including the properties of beta radiation that make it suitable for this application.
Comparing Imaging Techniques: Explore and compare different medical imaging techniques, focusing on image resolution, convenience, and safety considerations.
Gamma Camera: Structure & Function: Explore the key components of a gamma camera, including the photomultiplier tube, and understand how it functions to produce medical images.
Gamma-Emitting Radioisotopes as Tracers: Explore the use of gamma-emitting radioisotopes in medical imaging, including technetium-99m, iodine-131, and indium-111. Investigate their properties such as radiation emitted, half-life, gamma radiation energy, and their ability to label compounds for specific organ affinity.
The Molybdenum-Technetium Generator: Understand the basic function and significance of the Molybdenum-Technetium generator in producing technetium-99m for medical imaging.
Introduction to PET Scans: Learn the basics of Positron Emission Tomography (PET) scans and their application in medical diagnostics.
Physical, Biological and Effective Half-lives: Explore the different types of half-lives relevant to medical physics: physical, biological, and effective. Learn how they are defined and related through a given equation, enabling you to calculate the effective half-life of a radiopharmaceutical in the body.
More in this course
Go back to the full A Level AQA Physics topic list, or practise this topic with past-paper questions.
Medical physics (A-level only) covers Physics of the eye (A-level only), Physics of the ear (A-level only), Biological measurement (A-level only), and Non-ionising imaging (A-level only) in A Level AQA Physics. 34 lessons in 6 subtopics.
What is an ECG?
An electrocardiogram (ECG) is a recording of the electrical potential differences generated by the heart's muscle activity, detected by electrodes at the body surface and plotted as voltage against time. The Understanding ECG Waveforms notes cover this in full.
What is astigmatism?
Astigmatism is a refractive defect caused by an irregularly shaped cornea or lens whose curvature differs between perpendicular planes, so rays in one plane focus at a different distance from rays in the other. The Common Eye Defects notes cover this in full.
What is a CT scan used for?
CT scans are used for tumour detection, internal bleeding and complex anatomy, where good soft-tissue contrast and cross-sectional detail are needed. The CT Scanner Principles notes cover this in full.
Why does pneumonia show up on a chest X-ray?
In pneumonia, fluid replaces air in the alveoli. The Differential Tissue Absorption notes cover this in full.
How does an MRI scanner work?
A superconducting magnet creates a strong field, typically 1.5 T to 3 T, so hydrogen protons align with spins parallel to it and precess at the Larmor frequency. The MRI: Alignment and Precession notes cover this in full.
How long is a normal QRS complex?
A normal QRS complex lasts less than 0.12 s, while a P wave typically lasts around 0.08–0.10 s. The Understanding ECG Waveforms notes cover this in full.
What does a PET scan show?
A PET scan shows function rather than just anatomy. The Comparing Imaging Techniques notes cover this in full.
What is presbyopia?
Presbyopia is the decrease in the eye's range of accommodation with age, as the crystalline lens becomes less elastic. The The Eye as an Optical System notes cover this in full.