24.3 PET scanning

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.