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Faculty of Health & Wellbeing

Radiotherapy & Oncology

Pre Treatment Area Workbook

Name: …………………………………..

Placement: ……………………………

Contents

1.0 Introduction 3

2.0 Learning objectives 4

3.0 Development Path 5

4.0 Introduction to equipment and use of the simulator controls 6

4.1 The simulator 7

4.2 The controls 10

4.3 Simple simulator quality assurance checks 11

5.0 Introduction to the Radiotherapy CT scanner 12

5.1 Specialist Equipment 15

5.2 Couch Indexing 16

5.3 CT Borehole 17

5.4 CT Simulation Software 18

5.5 External Positioning Lasers 20

5.6 Beams Eye View 22

5.7 CT slice Thickness 23

6.0 Terminology used in pre-treatment 25

6.1 Anatomical abbreviations 25

6.2 The simulator area 28

7.0 The local rules for pre-treatment 33

8.0 Surface anatomy 34

8.1 Basic anatomy of the human body 34

8.2 Radiographic anatomy 39

9.0 Patient positioning and Acquisition of patient data 47

9.1 Patient Positioning and immobilisation 47

9.2 Acquisition of patient data 48

9.3 Obtaining a contour 48 10.0 Mould Room Activities 50

10.1 Mould room activities check list 50

10.2 Procedural report -construction of a low melting point

alloy electron cut out 52

10.3 Procedural report -construction of low melting point

alloy shielding blocks 53

10.4 Making a thermoplastic shell 54

11.0 Appropriate instructions/explanations given to patients 55

12.0 Localisation of a palliative chest 56

13.0 Planning and Verification- The pre-treatment process 61

14.0 Palliative Pre-treatment case report example (T-Spine) 65

15.0 Radical Pre-treatment case report example (Prostate) 69

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 pre-treatment 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

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

3.0 Development Path

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.

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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.

Diagnostic Couch Top:

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RT Couch Top:

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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.

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All immobilisation is indexed thus limiting the chances of a geographical miss

5.3 CT Scanner Bore Hole

Patient position can be limited by the CT aperture.

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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.

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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

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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.

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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

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)).

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5.7 CT Slice thickness

The CT scanner produces DRR images by reconstructing the CT slices taken during a scan together.

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

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).

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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?

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.

|FSD |

|Definition: |

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|When would this term be used in pre-treatment? |

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|FFD |

|Definition: |

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|When would this term be used in pre-treatment? |

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|ODI - Optical Distance Indicator |

|Definition: |

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|Outline an example of how this piece of equipment may be used in a pre-treatment procedure: |

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|Isocentre: |

|Definition: |

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|Wires (for departments using a conventional simulator) |

|Definition: |

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|Also known as: |

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|Outline an example of how this term may be used in a pre-treatment procedure: |

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|Blades (for departments using a conventional simulator) |

|Definition: |

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|Also known as: |

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|Outline an example of how this term may be used in a pre-treatment procedure: |

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|Image intensifier (for departments using a conventional simulator) |

|Definition: |

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|Outline an example of how this piece of equipment may be used in a pre-treatment procedure: |

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|Field Size |

|Definition: |

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|Outline an example of how this term may be used in a pre-treatment procedure: |

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|Magnification |

|Definition: |

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|Outline an example of how this term may be used in a pre-treatment procedure: |

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|Bolus |

|Definition: |

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|Outline an example of how bolus may be used in a pre-treatment procedure: |

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|Equivalent Square |

|Definition: |

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|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: |

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|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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|Percentage Depth Dose |

|Definition: |

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|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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|D Max |

|Definition: |

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|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.

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.

8.1 Basic Anatomy of the Human Body

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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).

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:

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Imaging technique: Imaging technique:

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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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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:

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1 ILIAC CREST

2 ACETABULUM

3 GREATER TROCHANTER

4 LESSER TROCHANTER

5 SYMPHYSIS PUBIS

6 SACRUM

7 COCCYX

8 HEAD OF FEMUR

9 NECK OF FEMUR

10 LUMBAR VERTEBRAE 5

11 SACROILIAC JOINT

12 OBTURATOR FORAMEN

13 PELVIC BRIM

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.

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1 OCCIPUT

2 HYOID BONE

4 ATLAS

5 SPINAL CORD

6 MANDIBLE

7 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?

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:

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.

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.

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.

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 room procedures

3. Hygiene and Emergencies:

Disposal of clinical waste

Fire extinguishers and exits

Oxygen and suction

Disposal of mould room materials

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)

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 _______

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.

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.

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?):

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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3/4 weeks

2 weeks

Start

Production of beam direction shells

Surface Anatomy/ landmarks/regional anatomy

Terminology used in Pre Trt

Methods of Contouring and obtaining organ information

Patient Positioning and immobilisation

Identifying Anatomy on Simple Radiographs

Introduction to the pre-treatment and use of the controls

Local Rules and Radiation Protection

Planning and localisation of palliative chest and pelvis techniques

Obtaining an accurate contour/CT

Common Target Volumes and dose fractionation schedules for palliative techniques

Medial

Lateral

Anterior

Posterior

Superior

Inferior

Sagittal

Coronal

Anterior

Left lateral

Posterior

Right lateral

Right anterior oblique (approx)

Right posterior oblique (approx)

Left anterior oblique (approx)

Left Posterior Oblique (approx)

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

___________ Foramen

___________

Joint

__________ Crest

The point where the trachea bifurcates is also called the ______

See AP chest

Right main __________

1.

Clinical application:

2.

Clinical application:

3.

Clinical application:

4.

Clinical application:

5.

Clinical application:

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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Positioning Aids

1.

Reason for its use:

2.

Reason for its use:

3.

Reason for its use:

4.

Reason for its use:

The Procedure for obtaining a contour for _______________________is:

Advantages of this method:

Disadvantages of this method:

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:

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:

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:

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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