24. Medical physics

understand that a piezo-electric crystal changes shape when a p.d. is applied across it and that the crystal generates an e.m.f. when its shape changes.

Use —a piezo-electric crystal changes shape when a p.d. is applied across it and to connect the rule to the data and decision in the question.

This matters because —a piezo-electric crystal changes shape when a p.d. is applied across it and determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply —a piezo-electric crystal changes shape when a p.d. is applied across it and to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: —A piezo-electric crystal changes shape when a p.d. is applied across it and is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

understand how ultrasound waves are generated and detected by a piezoelectric transducer.

Use —ultrasound waves are generated and detected by a piezoelectric transducer to connect the rule to the data and decision in the question.

This matters because —ultrasound waves are generated and detected by a piezoelectric transducer determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply —ultrasound waves are generated and detected by a piezoelectric transducer to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: —Ultrasound waves are generated and detected by a piezoelectric transducer is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

understand how the reflection of pulses of ultrasound at boundaries between tissues can be used to obtain diagnostic information about internal structures.

Use —the reflection of pulses of ultrasound at boundaries between tissues can be to connect the rule to the data and decision in the question.

This matters because —the reflection of pulses of ultrasound at boundaries between tissues can be determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply —the reflection of pulses of ultrasound at boundaries between tissues can be to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: —The reflection of pulses of ultrasound at boundaries between tissues can be is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

define the specific acoustic impedance of a medium as Z = ρc, where c is the speed of sound in the medium.

Use —the specific acoustic impedance of a medium as z = ρc to connect the rule to the data and decision in the question.

This matters because —the specific acoustic impedance of a medium as z = ρc determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply —the specific acoustic impedance of a medium as z = ρc to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: —The specific acoustic impedance of a medium as Z = ρc is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

use IR / I0 = (Z1 – Z2)2 / (Z1 + Z2)2 for the intensity reflection coefficient of a boundary between two media.

Use —ir / i0 = (z1 – z2)2 / (z1 + z2)2 for the intensity reflection coefficient to connect the rule to the data and decision in the question.

This matters because —ir / i0 = (z1 – z2)2 / (z1 + z2)2 for the intensity reflection coefficient determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply —ir / i0 = (z1 – z2)2 / (z1 + z2)2 for the intensity reflection coefficient to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: —IR / I0 = (Z1 – Z2)2 / (Z1 + Z2)2 for the intensity reflection coefficient is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

recall and use I = I0e–µx for the attenuation of ultrasound in matter.

Use —i = i0e–µx for the attenuation of ultrasound in matter to connect the rule to the data and decision in the question.

This matters because —i = i0e–µx for the attenuation of ultrasound in matter determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply —i = i0e–µx for the attenuation of ultrasound in matter to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: —I = I0e–µx for the attenuation of ultrasound in matter is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

explain that X-rays are produced by electron bombardment of a metal target and calculate the minimum wavelength of X-rays produced from the accelerating p.d.

Use —that x-rays are produced by electron bombardment of a metal target and to connect the rule to the data and decision in the question.

This matters because —that x-rays are produced by electron bombardment of a metal target and determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply —that x-rays are produced by electron bombardment of a metal target and to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: —That X-rays are produced by electron bombardment of a metal target and is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

understand the use of X-rays in imaging internal body structures, including an understanding of the term contrast in X-ray imaging.

Use —the use of x-rays in imaging internal body structures to connect the rule to the data and decision in the question.

This matters because —the use of x-rays in imaging internal body structures determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply —the use of x-rays in imaging internal body structures to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: —The use of X-rays in imaging internal body structures is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

recall and use I = I0e–µx for the attenuation of X-rays in matter.

Use —i = i0e–µx for the attenuation of x-rays in matter to connect the rule to the data and decision in the question.

This matters because —i = i0e–µx for the attenuation of x-rays in matter determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply —i = i0e–µx for the attenuation of x-rays in matter to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: —I = I0e–µx for the attenuation of X-rays in matter is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

understand that computed tomography (CT) scanning produces a 3D image of an internal structure by first combining multiple X-ray images taken in the same section from different angles to obtain a 2D image of the section, then repeating this process along an axis and combining 2D images of multiple sections.

Use —computed tomography (ct) scanning produces a 3d image of an internal to connect the rule to the data and decision in the question.

This matters because —computed tomography (ct) scanning produces a 3d image of an internal determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply —computed tomography (ct) scanning produces a 3d image of an internal to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: —Computed tomography (CT) scanning produces a 3D image of an internal is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

understand that a tracer is a substance containing radioactive nuclei that can be introduced into the body and is then absorbed by the tissue being studied.

Use —a tracer is a substance containing radioactive nuclei that can be introduced to connect the rule to the data and decision in the question.

This matters because —a tracer is a substance containing radioactive nuclei that can be introduced determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply —a tracer is a substance containing radioactive nuclei that can be introduced to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: —A tracer is a substance containing radioactive nuclei that can be introduced is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

recall that a tracer that decays by β+ decay is used in positron emission tomography (PET scanning).

Use —that a tracer that decays by β+ decay is used in positron emission to connect the rule to the data and decision in the question.

This matters because —that a tracer that decays by β+ decay is used in positron emission determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply —that a tracer that decays by β+ decay is used in positron emission to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: —That a tracer that decays by β+ decay is used in positron emission is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

understand that annihilation occurs when a particle interacts with its antiparticle and that mass–energy and momentum are conserved in the process.

Use —annihilation occurs when a particle interacts with its antiparticle and that to connect the rule to the data and decision in the question.

This matters because —annihilation occurs when a particle interacts with its antiparticle and that determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply —annihilation occurs when a particle interacts with its antiparticle and that to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: —Annihilation occurs when a particle interacts with its antiparticle and that is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

explain that, in PET scanning, positrons emitted by the decay of the tracer annihilate when they interact with electrons in the tissue, producing a pair of gamma-ray photons travelling in opposite directions.

Use —that, in pet scanning, positrons emitted by the decay of the tracer to connect the rule to the data and decision in the question.

This matters because —that, in pet scanning, positrons emitted by the decay of the tracer determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply —that, in pet scanning, positrons emitted by the decay of the tracer to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: —That, in PET scanning, positrons emitted by the decay of the tracer is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

calculate the energy of the gamma-ray photons emitted during the annihilation of an electron-positron pair.

Use —the energy of the gamma-ray photons emitted during the annihilation of an to connect the rule to the data and decision in the question.

This matters because —the energy of the gamma-ray photons emitted during the annihilation of an determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply —the energy of the gamma-ray photons emitted during the annihilation of an to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: —The energy of the gamma-ray photons emitted during the annihilation of an is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

understand that the gamma-ray photons from an annihilation event travel outside the body and can be detected, and an image of the tracer concentration in the tissue can be created by processing the arrival times of the gamma-ray photons.

Use —the gamma-ray photons from an annihilation event travel outside the body and to connect the rule to the data and decision in the question.

This matters because —the gamma-ray photons from an annihilation event travel outside the body and determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply —the gamma-ray photons from an annihilation event travel outside the body and to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: —The gamma-ray photons from an annihilation event travel outside the body and is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.