Faculty of Health & Wellbeing
Radiotherapy & Oncology
Pre Treatment Area Workbook
Name: …………………………………..
Placement: ……………………………
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Contents
1.0
2.0
3.0
4.0
Introduction
Learning objectives
Development Path
Introduction to equipment and use of the simulator controls
4.1
The simulator
4.2
The controls
4.3
Simple simulator quality assurance checks
5.0
Introduction to the Radiotherapy CT scanner
5.1
Specialist Equipment
5.2
Couch Indexing
5.3
CT Borehole
5.4
CT Simulation Software
5.5
External Positioning Lasers
5.6
Beams Eye View
5.7
CT slice Thickness
6.0
Terminology used in pre-treatment
6.1
Anatomical abbreviations
6.2
The simulator area
7.0
The local rules for pre-treatment
8.0
Surface anatomy
8.1
Basic anatomy of the human body
8.2
Radiographic anatomy
9.0
Patient positioning and Acquisition of patient data
9.1
Patient Positioning and immobilisation
9.2
Acquisition of patient data
9.3
Obtaining a contour
10.0 Mould Room Activities
10.1
Mould room activities check list
10.2
Procedural report -construction of a low melting point
alloy electron cut out
10.3
Procedural report -construction of low melting point
alloy shielding blocks
10.4
Making a thermoplastic shell
11.0 Appropriate instructions/explanations given to patients
12.0 Localisation of a palliative chest
13.0 Planning and Verification- The pre-treatment process
14.0 Palliative Pre-treatment case report example (T-Spine)
15.0 Radical Pre-treatment case report example (Prostate)
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1.0 Introduction
The purpose of the workbook is to enhance the theoretical principles covered
in academic and to aid and direct your learning within the clinical pretreatment area including the mould room and pre-treatment areas.
You should attempt to complete all sections including the tasks.
The completion of this workbook will assist with your learning and
development in this area.
To complete this workbook it may be wise for you to discuss a timetable with
your mentor at the start of your placement, so that supervised tasks can be
planned in conjunction with clinical workloads.
Where you are requested to undertake activities that are not performed as
standard in your placement department you should discuss other potential
approaches with staff in the clinical environment (radiographers, clinicians,
physicists etc.) you should also ensure these practices are observed and the
activities completed during your cross-site or elective placements later in the
course. This also refers to the use of specific equipment.
2.0 Learning Objectives
Completing this workbook in conjunction with your clinical placement site will
meet the following learning outcomes.
By the end of their first year pre-treatment placement students will be able to:
1. identify and demonstrate the safe use of controls and accessory
equipment utilised in pre-treatment
2. greet patients, put them at their ease and explain procedures for simple
pre-treatment procedures and beam direction shell production
3. demonstrate a sound knowledge of surface and radiographic anatomy
(including cross sectional anatomy)
4. outline the steps involved in the pre-treatment process
5. contribute to the production of a clinically acceptable beam direction
shell and appreciate the patients' perspective of the impression
process
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You should also note that some learning outcomes include elements that
relate to both the treatment and pre treatment area’s including:

assess the patients pre-examination/pre-treatment condition and report
to the radiographers accordingly

demonstrate an awareness of the appropriate instructions/explanations
given to patients

assist in the accurate positioning of patients for pre-treatment and
treatment, using appropriate immobilisation devices

identify and demonstrate the safe use of the controls on equipment
handsets and couches

identify and demonstrate the safe use of accessory equipment utilised
during localisation and treatment set-ups

describe the functions of the control panels and demonstrate their
correct application where appropriate
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3.0 Development Path
Start
2 weeks
Terminology used in
Pre Trt
3/4 weeks
Patient Positioning and
immobilisation
Planning and localisation of
palliative chest and pelvis
techniques
Local Rules and Radiation
Protection
Introduction to the pretreatment and use of the
controls
Surface Anatomy/
landmarks/regional anatomy
Identifying Anatomy on
Simple Radiographs
Production of beam direction
shells
Obtaining an accurate
contour/CT
Common Target Volumes and
dose fractionation schedules for
palliative techniques
Methods of Contouring and
obtaining organ information
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The Radiotherapy CT Scanner
Introduction:
CT scanning is a way of localising all tumour volumes. CT has taken over
from the traditional simulator for localisation purposes.
In this section, we will be looking at the following:
 Radiotherapy Treatment Planning Process
 Specialist CT equipment for RT planning
Considerations of a CT scan
The two most important considerations to bear in mind during the localisation
of any tumour or planning process are:
 Treatment position reproducibility
 Accurate tumour localisation
Activity 1: Why is treatment reproducibility important?
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5.1 Specialist CT Equipment: Flat top CT Couches:
The position of the patient in CT must be replicated in the linear accelerator
for treatment purposes. As the linac couch is flat, the CT couch also needs to
be flat; this is seen in stark contrast to a diagnostic CT couch which is
concave.
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Diagnostic Couch Top:
RT Couch Top:
5.2 Immobilisation devices and indexed fixation points
The main aim in RT treatment delivery is to ensure that we as close as we
possibly can, replicate the position adopted by the patient in the RT planning
scan. This is in part achieved by appropriate couch and immobilisation device
indexing. On the lateral edges of the RT CT scanner and treatment couches,
are indexed fixation points, these can be seen below as notches along the
bed.
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These indexed couch notches are used in conjunction with immobilisation
devices i.e. head and neck frame. Therefore we know exactly at what point
the patient was laid in sup/inf on the bed when we come to treat as the
position of this head frame would be indexed from CT.
All immobilisation is indexed thus limiting the chances of a geographical miss
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5.3 CT Scanner Bore Hole
Patient position can be limited by the CT aperture.
Activity 2:
What is the CT aperture size in your department and what sort of patients
might this affect?
A number of CT scanners are available with differing borehole sizes.
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5.4 CT Simulation Software
After the patient has been scanned, the information is sent to the virtual
simulation environment. Here, the tumour and sensitive organs are outlined
as below, in order to create a 3D volume for the purposes of 3D planning and
conformal / Intensity Modulated Radiotherapy techniques.
Digitally Reconstructed Radiographs (DRR's)
Multiple outlines over multiple slides are reconstructed in the form
of a DRR.
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These DRRs allow us to form a 3D tumour volume as shown below
This is an example of a 3D planning volume which is produced by outlining as
in the previous image.
CT simulation software calculates the geometric centre of the tumour,
thus aiding the treatment planning process:
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External Positioning Lasers
Once the patient is straight and positioned correctly pen marks are drawn onto
the patients' skin prior to scanning. These can then be used to check if the
patient has moved during the scan and are then used as references once on
the treatment machine. After the scan they will be turned into permanent
tattoos.
Lasers are mounted in the following positions:
Wall mounted: At a fixed distance from the scan plane
Horizontal lasers: Defines the coronal plane, may have vertical movement
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Ceiling Mounted: Defines sagittal plane, may have horizontal movement
Skin marks are positioned at the CT laser intersection point.
This position is defined in the pre-treatment process. This point is then
tattooed as a permanent reference once the scan is complete.
Activity 3:
Detail the process in which the centre of the tumour position is localised and
how the tattoo position is decided.
5.6 Beams Eye View
Beam's Eye View (or BEV) is an imaging technique used in radiation therapy
for the quality assurance and planning of External Beam Radiation Therapy
treatments. These are primarily used to ensure that the relative orientation of
the patient and the treatment machine are correct. The BEV image will
typically contain the images of the patient's anatomy and the beam modifiers
(such as jaws or Multi-Leaf Collimators (or MLCs)).
5.7 CT Slice thickness
The CT scanner produces DRR images by reconstructing the CT slices taken
during a scan together.
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Activity 4: What slice sizes does the CT scanner in your department operate
with?
Activity 5: What are the implications if CT slice thickness in terms DRR
quality?
Virtual simulation software simulates field sizes and beam angles on the
patient.
Once a satisfactory plan has been achieved, the software is used to verify
adequate target volume coverage and avoidance of critical structures.
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6.0 Terminology Used In Pre Treatment:
Make some notes here in preparation for or during your placement to
remind yourself of the relevant terminology.
6.1 Anatomical abbreviations
4.1.
Anatomical abbreviations
Medial
Ensure that you know what the following anatomical abbreviations mean as
they are commonly used in pre-treatment patient set –up (write the definition
next to the term).
Lateral
Anterior
Posterior
Superior
Inferior
Sagittal
Coronal
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If a patient were supine on the simulator couch with their head to the gantry,
at what angle would you expect the gantry to be for the following fields to be
imaged?
Anterior
Left lateral
Posterior
Right lateral
Right anterior oblique (approx)
Right posterior oblique (approx)
Left anterior oblique (approx)
Left Posterior Oblique (approx)
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6.2 Pre-treatment
The terms in the following table are used frequently in the pre-treatment area.
It is therefore important that you fully understand these and are able to
differentiate between them at the time of undertaking pre-treatment
procedures.
Provide definitions for each of the terms (ensure that if you take the definitions
from textbooks you reference them). Alternatively you can describe the terms
in your own words.
It is also important that you are able to relate the terms to pre treatment
procedures, you should therefore, where indicated; provide an example in
which the term would be used in clinical practice.
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FSD
Definition:
When would this term be used in pre-treatment?
FFD
Definition:
When would this term be used in pre-treatment?
ODI - Optical Distance Indicator
Definition:
Outline an example of how this piece of equipment may be used in a pretreatment procedure:
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Isocentre:
Definition:
Wires
Definition:
(for departments using a conventional simulator)
Also known as:
Outline an example of how this term may be used in a pre-treatment
procedure:
Blades
Definition:
(for departments using a conventional simulator)
Also known as:
Outline an example of how this term may be used in a pre-treatment
procedure:
Image intensifier
Definition:
(for departments using a conventional simulator)
Outline an example of how this piece of equipment may be used in a pretreatment procedure:
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Field Size
Definition:
Outline an example of how this term may be used in a pre-treatment
procedure:
Magnification
Definition:
Outline an example of how this term may be used in a pre-treatment
procedure:
Bolus
Definition:
Outline an example of how bolus may be used in a pre-treatment procedure:
Equivalent Square
Definition:
Outline an example of how this term would be used in a pre- treatment
procedure e.g. consideration of treatment prescription:
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Depth Dose
Definition:
Outline an example of how this term would be used in a pre- treatment
procedure e.g. consideration of treatment prescription:
Percentage Depth Dose
Definition:
Outline an example of how this term would be used in a pre- treatment
procedure e.g. consideration of treatment prescription:
D Max
Definition:
Outline an example of how this term would be used in a pre- treatment
procedure e.g. consideration of treatment prescription:
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7.0 The Local Rules for Pre Treatment
It is important that you read the local rules for each of the Pre treatment areas.
This is to ensure you comply with radiation safety precautions for the area.
Task 1
Read the Local Rules and then list below the important principles for radiation
safety included in these systems of work, under the following headings:
Personal Staff Safety
Minimising the Radiation Dose to the Patient
Minimising Radiation Exposure of the General Public
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8.0 Surface and Regional Anatomy
Due to the nature of the Pre Planning process it is necessary to have a good
working knowledge of surface landmarks, and radiographic regional anatomy.
This section contains useful diagrams to aid your knowledge in this area.
Some of the following diagrams are complete others have labels that need
completing.
The first section shows a schematic representation of human anatomy to aid
learning, you are then asked to give the surface landmarks for some
commonly used set up points.
The later sections show anatomy as observed on a radiograph, you will notice
a difference between these. Try to label the radiographs using the knowledge
you have gained from the preceding images.
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8.1 Basic Anatomy of the Human Body
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__________ Crest
___________
Joint
___________ Foramen
The point where the
Right main
trachea bifurcates is
__________
also called the ______
See AP chest
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8.2 Radiographic Anatomy
It is important that your awareness of basic human anatomy is now extended
from recognition of landmarks and structures in a diagrammatic form to being
able to identify them from different types of radiographic image. This may
prove a little more difficult at your first attempt, but it will begin to get easier
with practice.
Task 6: Use the resources around you in the pre-treatment area (and the staff
if necessary) to produce a list of the different imaging techniques that are
used in and support the pre-treatment process. Your first example may be
MRI!
For each technique write no more than three lines describing how the images
are acquired, and provide an example of a clinical application of each (what
diagnosis/tumour site can be imaged in this way).
1.
Clinical application:
2.
Clinical application:
3.
Clinical application:
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4.
Clinical application:
5.
Clinical application:
Task 7:
Imaging techniques used in the pre-treatment process: Match the descriptions
from the previous task to the images on this page.
This section is available on blackboard if you struggle to see the images
clearly.
Label each image with the name of the technique used for its acquisition:
Imaging technique:
Imaging technique:
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Imaging technique:
Imaging technique:
Imaging technique:
Imaging technique:
Task 8
Anatomy of the thorax
Identify the structures and landmarks on the AP chest radiograph below by
placing the number that corresponds to the structure on the radiograph:
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1. Clavicles
2. Carina
3. Right Middle Lobe
4. Right Upper Lobe
5. Diaphragm
6. Left Lower Lobe
7. Right Lower Lobe
8. Trachea
9. Pleura
10. Arch of Aorta
11. Thoracic Spine 12
12. Heart
13. Cervical Vertebrae 7
14. Mandible
15. Scapulae
16. Stomach
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Task 9
Anatomy of the pelvis
Identify the structures and landmarks on the AP pelvis radiograph below by
placing the number which corresponds to the structure on the radiograph:
1
ILIAC CREST
10 LUMBAR VERTEBRAE 5
2
ACETABULUM
11 SACROILIAC JOINT
3
GREATER TROCHANTER
12 OBTURATOR FORAMEN
4
LESSER TROCHANTER
13 PELVIC BRIM
5
SYMPHYSIS PUBIS
6
SACRUM
7
COCCYX
8
HEAD OF FEMUR
9
NECK OF FEMUR
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Task 10
Anatomy of the head and neck
Identify the structures and landmarks on the Lateral head/neck radiograph
below by placing the number which corresponds to the structure on the
radiograph.
1
2
4
5
6
7
OCCIPUT
HYOID BONE
ATLAS
SPINAL CORD
MANDIBLE
PITUITARY FOSSA
A useful way of helping to localise tumours is by using external surface
anatomy (prominent bones for example). What do you think are the
advantages of doing this from the point of view of the patient?
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Locating Vertebral Levels during simulation
It is often difficult to assess the level of vertebra you are screening in the
clinical setting due to poor image quality. If this is the case, a sound
awareness of how to identify the differing vertebral levels is a distinct
advantage.
One of the most commonly used ways of identifying a vertebral level is by
locating the last rib attached to a vertebral body. In doing this, you have
located vertebral body Thoracic 12.
Knowing this you can then identify up and down the vertebral column which
vertebrae follow on from this landmark.
Task 11 - Identify T12 on the radiograph below
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It is important to know which vertebral levels relate to external bony anatomy,
so the next task involves you revisiting the spinal column in order to find out at
what vertebral levels specific bony landmarks are situated.
Vertebral Levels
Remind yourself of how many vertebrae make up each section of the spine:
Cervical vertebrae No of vertebrae =
Thoracic vertebrae No of vertebrae =
Lumbar vertebrae No of vertebrae =
Sacrum and Coccyx
At which vertebral level does each of the following structures arise?
1. Vocal cords
2. Sternal angle
3. Commencement of Oesophagus
4. Commencement of trachea
5. Oesophageal opening into
Diaphragm
6. Symphasis pubis
7. Kidneys
8. Sternal notch
9. Umbilicus
10. Carina (bifurcation of the trachea)
11. Iliac crest
12. Xiphisternum:
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9.0 Patient Positioning and Acquisition of Patient Data
9.1. Patient Positioning and Immobilisation
During your clinical experience to date you will have been introduced to some
of the common treatment positions adopted in radiotherapy. Give a site for
each of the examples below:





Supine with head shell
Prone on mattress
Supine
Prone
Supine on inclined board.
In addition list below at least 4 immobilisation devices you have seen used
during the planning process (e.g. knee blocks), for each case identify the
reason behind its use.
Positioning Aids
1.
Reason for its use:
2.
Reason for its use:
3.
Reason for its use:
4.
Reason for its use:
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9.2 Obtaining a Contour
In this section you are required to define a procedure you have seen for
obtaining a patient contour (either manually, via CT, computer software, etc.).
This should be written in list form.
The Procedure for obtaining a contour for _______________________is:
Advantages of this method:
Disadvantages of this method:
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9.3 Acquisition of Patient Data
In order to complete the pre planning process it is often necessary to obtain
further details of normal tissue structures in close proximity to the target
volume. For the following cases give a brief description of how patient data is
obtained in your clinical department.
Lung position for patients planned for radical breast irradiation:
Position of the rectum in radical treatments for Prostate malignancies:
The position of the spinal cord for consolidation radiotherapy for small cell
lung cancer:
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10.0 Mould Room Activities
As part of your pre-treatment placement you will be gaining some experience
in the mould room. The checklist below will give you an idea of what you will
need to focus on during your time here.
10.1 MOULD ROOM ACTIVITIES CHECKLIST
1.
Locate and read:
Policy/protocol file
Relevant safety and fire regulations
2.
Shadow and then undertake:
Correct patient identification and reception
Basic
explanations
of
mould
procedures
3.
Hygiene and Emergencies:
Disposal of clinical waste
Fire extinguishers and exits
Oxygen and suction
Disposal of mould room materials
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room
4.
Administration:
Outline the diary system and the procedure
for future appointments (e.g. with mould
room, simulator)
5.
Observe and then participate (where possible) in:
Construction of a low melting point alloy
Electron cut-out
Construction of a beam direction shell
Document the procedure for the above two items on the sheets
following this checklist.
6.
Where possible, observe and then participate in:
Construction of a Pb mask
Construction of a mouth bite (tongue
depressor)
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10.2 Task: MOULD ROOM: PROCEDURAL REPORT
PROCEDURE FOR THE CONSTRUCTION OF A LOW MELTING POINT
ALLOY ELECTRON CUTOUT
Signature of Mould Room Staff_______________________ Date _______
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10.3 Making a Thermo Plastic Shell
One of the most common tasks undertaken in the mould room is the
production of a beam directional mask. The purpose of the mask is to improve
treatment accuracy in radiotherapy techniques to the head and neck area.
This is achieved by maintaining a fixed head position throughout treatment.
Under this section you are required to observe the procedure used to
construct an immobilisation device.
Write the stages of the process here, and comment on how this experience
is perceived by patients.
11.0 Appropriate instructions/explanations given to patients.
Read the relevant protocol and observe the radiotherapists greeting patients,
providing information to patients before and after the pre treatment
procedures (in both mould room and pre-treatment). Make notes here. Also try
to reflect upon how radiographers use their skills to put patients at ease
before and during the procedure.
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12.0 Localisation of a Palliative Chest
In this section you will be introduced to the procedure for localisation of
palliative thoracic fields. It is important that you are able to narrate through the
processes involved in undertaking localisation of a patient with advanced lung
cancer. This is good preparation for the case discussion (clinical
assessment) you will undertake which relates to your pre treatment
experience.
By now you will have read the local protocols for a procedure such as this and
should have been involved in caring for the patient during this type of
procedure. Under the following headings write an account of how the
radiotherapist would be involved and what skills they would use for
undertaking this type of procedure.
Pre-treatment paper work and preparation:
Documentation needed in order for localisation to take place:
Other preparatory procedures:
(E.g. inputting patient data into verification system)
Summary of skills needed:
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Pre-treatment patient preparation (Description and Rationale):
Aspects of patient status that need checking and reason why:
Summary of skills needed:
Pre-treatment room preparation for localisation procedure (Actions and
rationale):
Summary of skills needed:
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Patient position (Position using anatomical terminology):
Rationale for position:
Method of immobilisation:
Factors affecting patient position and alternative treatment positions for this type
of patient:
Summary of skills needed:
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3.0 Planning and Verification- The pre treatment process:
Now that you have looked at the availability and use of the equipment in the
pre treatment area, its quality assurance and safe use, and begun to look at
the process of localisation of palliative treatments in more detail, try to follow
the journey of a patient who is having some form of Radical treatment (Head
and Neck) treatment process (localisation, planning & verification) to
treatment and document the stages below.
Comment upon the following aspects of the process:
The use of imaging modalities & equipment for localisation of the tumour:
Method of obtaining the external contour of the patient
How the external reference/field marks placed onto the patient:
The transfer of information to the treatment planning department (or if using
virtual simulation - how/when does the planning process take place?):
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Who is responsible for outlining the tumour volumes and critical structures
(internal contouring)?
Briefly summarise the role of other health professionals within the pre
treatment process e.g. Clinicians (Dr's), Medical Physicists, dosimetrists,
planning radiographers, nursing staff, clinic/administration/other support staff:
How is the treatment plan verified before treatment?
How is the information recorded and transferred to the treatment unit?
Try to apply a similar approach as in Section 10 & 11 to the completion of pre
treatment case reports on localisation/verification of treatments.
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