Medical Option Syllabus

This option offers an opportunity for students with an interest in biological and medical topics to study some of the applications of physical principles and techniques in medicine. It involves detailed learning as well as application of principles to problems and the use and manipulation of equations.

It builds upon topics covered throughout the course and the studying of this course should be used as an opportunity to practise applying and clarify concepts met in the two years of your studies.

Course delivery

Each week you will receive two periods of teacher led lecture-type lessons with the teacher who specializes in your option, two periods of private study lessons and two periods of tutorial as a whole group.

The private study lessons should be used to prepare for the active lecture sessions. You will be set reading and note taking preparation as homework. The pace of the 'contact' lessons will therefore be high (similar to what you will get at University). You will be expected to be familiar with the terminology and already have made basic notes from the text. The session will be an opportunity for you to clarify misunderstandings and to appreciate the application of the knowledge that will be expected from you.

Calculation and problem solving homeworks will also be set. It is suggested that you congregate in a group during the private study sessions. This will allow peer discussion and throw up points that need to be raised in the teacher contact sessions.

Text Book: Medical Physics by Jean Pope

Calculation Book: Calculations for A-level Physics (Lowe and Rounce)

Additional Web-based support Material can be accessed via hyperlinks

This is an excellent site.

Syllabus Details		References	You should be able to...
Section 15.5 - The Physics of the eye (past paper questions and solutions) and ear (past paper questions and solutions)-
15.5.1	Physics of vision: Simple structure of the eye The eye as an optical refracting system; including ray diagrams of image formation	Pope pp 28-32	label a diagram of the eye and know the function of each part draw ray diagrams to represent the rays being refracted by the optical system (as in Pope)
15.5.2	Sensitivity of the eye Spectral response as a photodetector	Pope pp 32-36	diagrams on pages 32, 33and 35 should be known and understood- they have come up in questions in the past Maximum refaction occus at the air cornea interface - the lens only provides minor adjustments in focus. - know diagram too! depth of focus with a small pupil is large - little adjustment is needed for focusing at differenet object distances - lttle strain when viewing in bright light. The converse is true for a large pupil.- know diagram too! Rods and cones should be known in detail - learn the graphs on page 35 - you should be able to sketch them from memory with numbers on the axes.
15.5.3	Spatial resolution Explanation in terms of the behaviour of rods and cones	Pope pp 36-32	the diagram on page 36 should be known and understood
15.5.4	Persistence of vision (excluding a physiological explanation)	Pope pp 39-40	recall the frequencies
15.5.5	Depth of field	Pope pp 40	for both monocular and binocular vision
15.5.6	Lenses Properties of converging and diverging lenses; principal focus, focal length and power Use of the equations: where f = the focal length (+ve for a convex lens and -ve for a concave one) u = the distance of the object from the centre (pole) of the lens, called the object distance v = the distance of the image from the centre (pole) of the lens, called the image distance (if the image is a virtual one this distance will be negative and the image will be on the same side of the lens as the object. M = magnification	Question 4b June 2000 Answer Q4b Jun 2000	You should recall that: a converging lens makes the rays come to a real focus (cross at a point) it is called a CONVEX lens a diverging lens makes the rays appear to be spreading out from a point on the opposite side of the lens (cross at a virtual point) it is called a CONCAVE lens The principal focus of a convex lens (sometimes called the focal point) it is the point on the principal axis, through which rays of light, travelling near to and parallel to the principal axis, pass after refraction by the lens. The principal focus of a concave lens (sometimes called the focal point) it is the point on the principal axis, from which rays of light, travelling near to and parallel to the principal axis, apear to diverge from after refraction by the lens. (they can be traced back through this point. The focal length of a lens is the distance between the pole of the lens and the principal focus. If the lens has a real focus then the focal length is positive. If it has a virtual focus it is negative. The power of a lens is the reciprocal of the focal length in metres. It is measured in dioptres (D). The sign of the power will be the same as the sign of the focal length. You should be able to do calculations using the equations - care with signs! and units!
15.5.7	Ray diagrams Image formation		You should be able to construct the following diagrams Convex lens: object at 2F, object between F and 2F, object at F , object between P and F and object beyond 2F Concave lens: object at 2F, object between F and 2F, object at F and object between P and F You MUST draw these properly - construct them! - sketches will not do! Use a ruler and a sharp pencil. Three basic rules to construc an image: Rays that pass through the pole of the lens are undeviated. Rays that are travelling parallel to and near to the principal axis pass through the principal focus after refraction by the lens (for a convex lens) and appear to emanate from the principal focus (draw in dotted lines) for a concave lens. The converse is true, in that rays passing through (or emanating from) the principal focus emerge parallel on the other side of the lens.
15.5.8	Defects of vision: myopia, hypermetropia and astigmatism	Question 4a June 2000 Answer Q4a Jun 2000
15.5.9	Correction of defects of vision using lenses Ray diagrams and calculations of powers (in dioptres) of correcting lenses for myopia and hypermetropia The format of prescriptions for astigmatism
15.5.10	Physics of hearing Speed of sound in solid and gaseous media
15.5.11	Acoustic impedance Definitions of intensity and attenuation
15.5.12	The ear as a sound detection system: Simple structure of the ear, transmission processes
15.5.13	Sensitivity and frequency response Production and interpretation of equal loudness curves Human perception of relative intensity levels and the need for a logarithmic scale to reflect this
15.5.14	Relative intensity levels of sounds Measurement of sound intensity levels and the use of dB and dBA scales
15.5.15	The threshold of hearing
15.5.16	Defects of hearing The effect on equal loudness curves and the changes experienced in terms of hearing loss of: - injury resulting from exposure to excessive noise; - deterioration with age (excluding physiological changes)		Noes on the Cyberphysics site - see table of problems with hearing
Section 15.6 - Biological measurement and imaging - fibre optics past paper questions and solutions heart past paper questions and solutions lasers papt paper questions and solutions ultrasound past paper questions and solutions X-ray past paper questions and solutions
15.6.1	Basic structure of the heart. The heart as a double pump with identified valves	Pope page 69/70	Note that full heart is not required but all in Pope is!
15.6.2	Electrical signals and their detection The biological generation and conduction of electrical signals; methods of detection of electrical signals at the skin surface	Pope chapter 5 (pp 67-73)
15.6.3	Action potentials The response of the heart to the action potential originating at the sino-atrial node	Pope page 68-69	You need to KNOW the diagrams!
15.6.4	Simple ECG machines and the normal ECG waveform Principles of operation for obtaining the ECG waveform; explanation of the characteristic shape of a normal ECG waveform	Pope page 70-72	All of the detail here can be asked for in the exam!
15.6.5	Ultrasound imaging: Reflection and transmission characteristics of sound waves at tissue boundaries, acoustic impedance Advantages and disadvantages of ultrasound imaging in comparison with alternatives including safety issues and resolution	Pope page 117-118 Pope page 130-131	Look to the notes on cyberphysics as well as your text book
15.6.6	Piezoelectric devices: Principles of generation and detection of ultrasound pulses	Pope page 118-119
15.6.7	A-scan and B-scan Examples of applications	Pope page 119-125
15.6.8	Fibre optics and lasers Properties of fibre optics and applications in medical physics; including total internal reflection at the core-cladding interface	Pope pages109-113	Revise AS work and then see how it is applied here
15.6.9	Endoscopy: Physical principles of the optical system of a flexible endoscope; the use of coherent and non-coherent fibre bundles; examples of use for internal imaging and related advantages	Pope pages109-113	Revise AS wok and then see how it is applied here
15.6.10	Properties of laser radiation Absorption by tissue	Pope pages 113-115
15.6.11	Uses of lasers in medicine Safety issues	Pope pages 113-115
15.6.12	X-ray imaging The physics of diagnostic X-rays	Pope pages136 - 160	see cyberphysics notes too
15.6.13	Physical principles of the production of X-rays: - rotating-anode X-ray tube; - methods of controlling the beam intensity, - the photon energy, - the image sharpness and contrast and - the patient dose	Pope pages 151-156	Important topic - make sure you know what each part does and why!
15.6.14	Differential tissue absorption of X-rays (excluding details of the absorption processes)	Pope pages 142-147	Note that you do NOT need details of the attenuation processes!
15.6.15	Exponential attenuation Linear coefficient m, mass attenuation coefficient m_m and half-value thickness x ( remember r is density!!)	Pope pages 142-144	You did something similar with gamma ray absorption
15.6.16	Image contrast enhancement: use of X-ray opaque material as illustrated by the barium meal technique	Pope page 149
15.6.17	Radiographic image detection Photographic detection with intensifying screen and fluoroscopic image intensification; reasons for using these	Pope page 148-151	Main reason for development of the intensifying screen etc. is to cut down on the dose of X-rays that has to be delivered. You need to use CALRAD to familiarize yourself with the procedures adopted to do this and the problems that can arise from ionizing radiation exposure. Cellular damage (within one person) can lead on to systemic (passed on to offspring) damage. See here.