Cambridge
TECHNICALS
OCR LEVEL 2
CAMBRIDGE TECHNICAL
CERTIFICATE/DIPLOMA IN
SCIENCE
RADIOLOGY
L/505/3125
LEVEL 2 UNIT 13
GUIDED LEARNING HOURS: 60
UNIT CREDIT VALUE: 10
RADIOLOGY
L/505/3125
LEVEL 2
AIM AND PURPOSE OF THE UNIT
Healthcare professionals regularly make use of a range of
radiological techniques. A number of methods of studying the
internal anatomy of a patient are used routinely and learners
may have prior knowledge of some diagnostic uses of, for
example, X-rays and ultrasound. They may, however, not be
familiar with the full range of techniques that are available.
The aim of this unit is to increase understanding of the way
in which different radiations can be used safely in a medical
context. This will allow healthcare workers to become well
informed about the techniques used. Consequently, they
will be able to support and reassure patients who are being
treated using, for example, X-rays and radioactive sources.
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2
Radiology Level 2 Unit 13
ASSESSMENT AND GRADING CRITERIA
Learning Outcome (LO)
Pass
Merit
Distinction
The assessment criteria are
the pass requirements for
this unit.
To achieve a merit the
evidence must show that, in
addition to the pass criteria,
the learner is able to:
To achieve a distinction the
evidence must show that,
in addition to the pass and
merit criteria, the learner is
able to:
The learner will:
The learner can:
1 Know how X-rays are
used by Diagnostic
Radiographers.
P1 outline the main
features of X-ray images
M1 explain how X-rays can
be used diagnostically
by a radiographer
P2 describe the use
of fluoroscopy and
angiography in the
diagnosis of disease
M2 explain how
fluoroscopy and
angiography operate as
a diagnostic technique
P3 describe how the
images produced using
computed tomography
(CT scan) differ from
those produced by
normal radiography
M3 outline how X-ray
computed tomography
(CT scan) can be used
to create a threedimensional image of
internal body structures
D1 describe the
advantages and
disadvantages of using
Magnetic Resonance
Imaging (MRI) as an
alternative to other
medical imaging
techniques
2 Know how a
Radiographer uses
ultrasound to observe
structures inside
bodies.
P4 describe how
ultrasound works
and how it is used to
produce an image of
internal structures
within the body
D2 explain how the time
taken for reflection is
used by a computer
to determine internal
structures within the
body
3 Know that radioactive
materials can be
used for diagnosis
and treatment
by a Therapeutic
Radiographer.
P5 describe how
radioactive sources can
be used as tracers
D3 justify the choice of
tracer in terms of
half-life and type of
radiation
3
Learning Outcome (LO)
The learner will:
Pass
Merit
Distinction
The assessment criteria are
the pass requirements for
this unit.
To achieve a merit the
evidence must show that, in
addition to the pass criteria,
the learner is able to:
To achieve a distinction the
evidence must show that,
in addition to the pass and
merit criteria, the learner is
able to:
The learner can:
P6 Describe the advantages
and disadvantages of
the use of radiation in
the treatment of cancer
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M4 describe methods
used to reduce risk
to surrounding tissue
when treating cancer
4
TEACHING CONTENT
The unit content describes what has to be taught to ensure that learners are able to access the highest grade.
Anything which follows an i.e. details what must be taught as part of that area of content.
Anything which follows an e.g. is illustrative, it should be noted that where e.g. is used, learners must know and be able to apply
relevant examples to their work though these do not need to be the same ones specified in the unit content.
LO1 Know how X-rays are used by Diagnostic
Radiographers.
-- The image produced is called an angiogram and can be
used by a radiologist to detect blockages in, narrowing
of and bleeding from, blood vessels.
• Detection of X-rays
-- Historically X-rays were detected using photographic
plate or film, although modern systems use digital
sensors.
-- Areas where X-rays reach the detector are recorded
on the sensor, as a different colour to those where no
X-rays are detected.
• Computed Tomography (CT scan)
-- In computed tomography, a large number of X-ray
images of ‘slices’of the body are made.
-- The large amount of data collected is processed by a
computer to produce a three-dimensional image of the
body.
-- The images are used to produce images of complex
fractures, study head injuries and to diagnose
abdominal diseases.
• Absorption of X-rays
-- Different parts of the body absorb X-rays by varying
amounts e.g. bones absorb X-rays more than skin
and muscle, gases do not absorb X-rays as much as
body tissue, and the variation in absorption allows
radiographs to be made.
-- X-rays are absorbed by cells in the body.
• Magnetic resonance imaging (MRI)
-- MRI techniques are used by radiographers to create
a two- or three-dimensional image of the internal
structures of a patient’s body.
-- Unlike CT scans, which expose patients to relatively
high levels of potentially damaging X-rays, the MRI scan
does not use any ionising radiation.
-- The images of soft tissue produced by MRI are clearer
than CT scans, making MRI a more useful technique for
studying the brain or heart.
-- CT scans are, however, usually more widely available,
quicker to produce and less expensive.
• Diagnostic uses of X-rays
-- X-rays can be used to locate breaks in bones using
shadow images.
-- Interpretation of radiographs e.g. showing cracked and
broken bones and cavities in teeth.
-- Chest X-rays are used to identify lung disease such as
pneumonia and lung cancer.
• Fluoroscopy
-- This is a technique that is used to produce ‘real time’
moving images of the workings of the body’s internal
structures.
-- When X-rays strike a screen coated with a suitable
chemical, the screen glows (fluoresces).
-- A patient is placed between the source of the X-rays
and a fluorecent screen to produce moving images of
internal structures.
LO2 Know how a Radiographer uses ultrasound to
observe structures inside bodies.
• What is ultrasound?
-- Sound that cannot be heard by humans because it has
a pitch (frequency) that is too high.
-- The ear of a healthy young adult does not ‘hear’ sounds
with frequencies higher than approximately 20000
hertz (Hz).
-- Ultrasound is produced by something vibrating more
• Angiography
than 20000 times each second with a frequency of 20
-- This is an adaptation of fluoroscopy that is used to
kilohertz (kHz).
study the inside of blood vessels and the body’s organs.
-- Radiographers use ultrasound that has a frequency in
-- Blood does not absorb X-rays well enough to form a
the range 1 to 18 megahertz (MHz), 1 MHz = 1000 kHz.
shadow, so a contrast agent that does absorb X-rays
• Echoes and their use in measuring distances
well has to be introduced into the blood stream.
-- Sound can be reflected when it hits a solid surface and
-- Contrast agents are often compounds of barium or
an echo is heard.
iodine and have a range of commercial brand names.
www.ocr.org.uk
5
Radiology Level 2 Unit 13
-- The time between making a sound and hearing the
echo at the same place can be used to calculate the
distance to a reflecting surface.
-- Distance to reflecting surface = ½ speed of sound x
time to hear the echo.
-- The speed of sound is different in different materials.
-- The radiation can be absorbed by cells in the body.
-- Strong doses of radiation can be used to destroy cancer
cells.
-- The radiation can damage DNA in cells and
subsequently, cause cancer.
-- Cancerous cells can be destroyed using a radioactive
source that is positioned outside the body, with its
radiation directed at the tumour.
-- An alternative is to use a radioactive implant placed
inside the body, either inside or close to a tumour.
• Ultrasonography
-- A probe which contains a device to generate
ultrasound and another to detect the ultrasound is
moved across a patient’s skin.
-- Whenever a sound wave hits the boundary between
different materials, part of the wave is reflected back to
the probe and is detected as an echo.
-- The time it takes for the echo to return back to the
probe is measured.
-- This time is used to calculate the depth of the
boundary.
-- The strength of the reflected wave can be used to
identify the type of materials that form the boundary.
-- A computer is used to process the large amount of
data collected to form an image showing the internal
structure of the body.
-- The technique has a wide range of uses, for example;
monitoring the development of a foetus during
pregnancy, studying internal organs such as the heart,
and assisting with the insertion of needles to avoid
contact with delicate parts of the body such as the
nervous system.
• Choice of source for radiotherapy
-- When using radiotherapy, care has to be taken to
make sure that damage to the non-cancerous cells
surrounding the tumour are minimised.
-- Radioactive materials emit three different types of
radiation; alpha, beta and gamma.
-- Gamma and alpha radiation are absorbed by body
tissues - alpha radiation is the least penetrating of the
three types and is absorbed only by a few millimetres
of body tissue, while gamma radiation is the most
penetrating and will be absorbed significantly by body
tissue.
-- Some radioactive sources emit ionising radiation for
longer than others.
-- The half-life of a radioactive source indicates how long
it takes for its activity to halve.
-- A short half-life means that the level of radiation
becomes safe relatively quickly.
-- The source used for a tracer has to emit radiation that
is able to penetrate tissue so that it can be detected
outside the body but remain active long enough to
allow the necessary measurements to be taken.
LO3 Know that radioactive materials can be used for
diagnosis and treatment by a Therapeutic Radiographer.
• Diagnosis - the use of radioisotopes as tracers
-- Tracers are specially prepared radioactive substances
that can be introduced into the body.
-- The journey of tracers around the body can be tracked
using a radiation detector that is placed outside the
body.
-- The behaviour of the isotopes can be used to identify
specific conditions e.g. the function of the thyroid
gland can be checked using a tracer; the thyroid
absorbs all forms of iodine from the blood and a tracer
containing a radioactive form of iodine is swallowed.
Some time later a radiation detector is used to measure
how much of the radioactive iodine has been absorbed
and how evenly it is distributed in the thyroid, to check
that the gland is working correctly.
• Treatment - the effect on cells of radiation from radioactive
materials
-- Radioactive materials emit ionising radiation.
6
DELIVERY GUIDANCE
LO1 Know how X-rays are used by Diagnostic
Radiographers
This could lead to a definition of ultrasound, as sound,
with a frequency greater than 20kHz. Learners could do
some research to find the range of frequencies used by
radiographers.
This section of the unit could be introduced by learners
researching the way in which X-rays were discovered. They
could be given a copy of Rontgen’s image of his wife’s hand
and asked to offer an explanation of why it looks as it does.
This could be followed up with a visit to a hospital to look
at the equipment that is used to produce radiographs, in a
modern context. They could identify the roles played by the
people who work in the X-ray department of a hospital. It
may also be possible to look at the equipment used for CT
and/or MRI scans. Learners could be shown or reminded that
light forms a shadow when it is blocked by an object and
relate this to the way in which a radiograph is made. Through
observation of radiographs, of different body areas, learners
could identify how radiographers and dentists use X-rays
diagnostically in the identification of broken bones, cavities in
teeth and disease in soft tissue.
Learners could design a demonstration to show that sound is
reflected by a surface to create an echo. Standing a suitable
distance away from the wall of a large building and bursting a
balloon could be used to measure the distance from balloon
to wall. Learners could measure the time elapsed before the
echo is heard. They could then be given a value for the speed
of sound in air (e.g. 330 m/s) and use the equation:- (distance
to reflecting surface = ½ speed of sound x time to hear echo)
to calculate the distance to the wall.
Learners could do research to find values for the speed of
sound in different substances to identify that the speed of
sound depends on the medium that it is travelling through.
They could also be shown that ultrasound can be detected
using a suitable transducer.
Learners could research how X-rays can be used to create
moving images of internal body structures (fluoroscopy) and
describe situations in which this process is useful e.g. pinning
bones with complex fractures. Learners could research how
angiography is used to study the inside of blood vessels and
organs of the body. Learners could be taught why a contrast
agent must be introduced into the bloodstream and why
moving images are of more use than still images. Learners
could research the risks associated with exposure to X-rays
and the way in which a patient is prepared for angiography.
They could produce an information sheet that supports a
nurse who is explaining to a patient why something has to be
put into their bloodstream and the precautions that will be
taken to minimise the risk to them.
Learners could collect images of developing foetuses and
research the way in which the images are formed. Learners
could be encouraged to use the ideas they have developed,
about the formation of echoes and how measuring the time
to detect an echo, can be used to measure the distance to
the reflecting surface. They could interview people who have
experienced the use of ultrasound diagnostically to discover
what is involved from a patient’s perspective. Learners could
use their interviews to identify other ways in which ultrasound
can be used diagnostically.
LO3 Know that radioactive materials can be used for
diagnosis and treatment by a Therapeutic Radiographer
To introduce the idea that radioactive sources can be used as
tracers, a radioactive source could be hidden in a dummy and
its position located using a Geiger counter. Learners could be
taught that the radioactive forms of elements that are found
in the body, can be used to monitor processes that occur in
the body. Learners could research a specific use of one of
these radioisotopes, for example, how radioactive iodine can
be used to check the function of the thyroid gland.
To complete the section learners could research the way
in which three-dimensional images of a patient’s body are
produced by CT and MRI scanners. They could be directed
to identify why using magnetic resonance imaging (MRI) is
inherently safer than a X-ray computed tomography (CT scan)
and consider the advantages of a CT scan in terms of speed,
avaiability and cost.
LO2 Know how a Radiographer uses ultrasound to
observe structures inside bodies.
Learners could be introduced to the idea that there are risks
associated with the use of radioactive sources and find out
what the risks are at cellular level. This could develop into
research as to why radioactive materials can be used, by a
therapeutic radiographer, to treat tumours. Learners could be
taught formally about the way in which an external source can
This section could be introduced by using a signal generator,
loudspeaker and frequency meter to measure the highest
frequency of sound that can be heard by individual learners.
www.ocr.org.uk
7
Radiology Level 2 Unit 13
be used to destroy cancer cells inside the body. The use of an
internal source implanted into or close to a tumour could also
be taught formally.
A demonstration, showing the absorption of gamma, beta
and alpha radiation could be given using radioactive sources,
suitable absorbers and appropriate radiation detectors.
This could lead to an appreciation of the different ways in
which gamma and alpha radiation are absorbed by body
tissue. Learners could use their observations to explain
why a radiographer would choose gamma radiation to
use externally and alpha radiation internally. They could
also research how shielding can be used to protect people
working with radioactive sources. Learners could also
be taught why the source chosen as a tracer should emit
radiation that can be detected outside the body.
Learners could be taught that some radioisotopes remain
dangerously radioactive for longer than others and that the
half-life is the time taken for the activity of the source to halve.
They could deduce that sources with a long half-life remain
active for longer than those with a short half-life and that, for
example, after seven half-lives the activity will have fallen to
less than 1% of its original activity. They could also identify
some of the radioisotopes that are commonly used in nuclear
medicine and find out their half-lives.
Learners could write to a local hospital or the NHS asking for
information about the ways in which the harmful effects, on
both patients and health care workers, of ionising radiation,
are minimised.
8
SUGGESTED ASSESSMENT SCENARIOS AND GUIDANCE ON ASSESSMENT
Criteria
Assignment
Scenario
Assessment
LO1
Using X-rays
Learners produce a report to
explain how X-rays can be used to
produce still and moving images
of bones and soft tissue, including
an interpretation of what can
be deduced from chest X-rays
and radiographs of the skeleton.
Learners can be given a list of key
words to give some structure to
their reports.
The assessment could be in the form of a PowerPoint
presentation with suitable images included.
P1 The learner will include an explanation of why
some parts of a radiograph are black and other
parts are lighter in colour.
M1 The learner will explain that bones absorb X-rays
and so they are shown as dark areas, because no
radiation reaches the detector and that gaps in
bones appear as lighter areas, so breaks in bones
can be located. They will also explain how a chest
X-ray would identify, for example, pneumonia.
P2 The pass grade is achieved when a learner’s
report of their research shows knowledge that
flouroscopy involves making moving X-ray
images and that the inside of blood vessels can
be studied.
M2 When a learner’s report of their research shows
knowledge of how moving X-ray images can
be made and describes two or more situations,
one involving fluoroscopy and one involving
angiography, in which this process is useful, the
merit grade is achieved.
P3 A learner who describes a CT scan as producing a
3-D image will achieve the pass grade.
M3 To achieve the merit grade, the learner should
show that they understand the way in which a
3-D image can be created by using a computer.
D1 A learner who provides a detailed and reasoned
description of the advantages and disadvantages
of MRI, in terms of, for example, clarity of images,
cost and safety, achieves the distinction grade.
LO2
Foetal
development
Learners could produce a leaflet
to inform mothers-to-be how
ultrasound will be used to produce
images of their child before it is
born.
P4 To achieve the pass grade, a learner’s leaflet
should make it clear that ultrasound is reflected
from surfaces within the body and that multiple
reflections are analysed by a computer, to build
up an image of the foetus.
D2 The learner’s leaflet will explain that the device
moved across the skin contains an emitter and
detector of ultrasound and that the time taken
for a pulse of ultrasound to be reflected back to
the point from where it was emitted is used, in
combination with the time taken by many other
pulses to be reflected, to calculate how far below
the surface the reflecting surface is. They will
also appreciate that a computer must be used to
process the large amount of data involved.
www.ocr.org.uk
9
Radiology Level 2 Unit 13
LO3
Radioactivity
in medicine
Learners research ways in which
radioactive sources can be used as
tracers and to treat cancer safely,
including the selection of sources
that emit the most appropriate
type of radiation and have a
suitable half life.
The assessment could be in the form of a report
on the use of radioactive sources in hospitals to
diagnose a specific condition and to treat tumours
using internal and external techniques
P5 Research completed by the learner will show
that the use of tracers, in a procedure, has been
understood if the pass grade has been achieved.
D3 The learner should explain why a specific source
is chosen in terms of its half life and the type
of radiation that is emitted. When a learner
explains that the half-life of a radioisotope, used
as a tracer, should be chosen to ensure that
the source remains active for no longer than is
needed and that a gamma radiation emitter may
be the best type to use, because little radiation
is absorbed by the body’s tissue and it can
be detected externally, a distinction grade is
achieved.
P6 To achieve a pass grade the learner must identify
that ionising radiation can damage healthy cells
but that it can be used to destroy cancerous cells.
M4 A merit grade is achieved if the learner provides
evidence that they understand that risks are
minimised by stopping X-rays reaching parts of
the body that do not need to be exposed and
that the time of exposure is kept to a minimum.
10
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