The Role of the Radiation Therapist Flashcards
What is RadioTherapy? What is its aim?
Treatment of cancer with ionising Radiation
1) kill tumour cells before they spread
2) reduce sizes of tumours to help symptoms
What are the ways we can treat cancer?
surgery, chemotherapy, hormone therapy, immunotherapy
What does EMR stand for?
electromagnetic radiation
What is immunotherapy?
We can place monoclonal antibodies into the patient. Essentially antibodies are grown and harvested from another organism (such as a mouse) these are then placed into the human to fight the cancer
What three factors can exacerbate cancer growth?
Smoking, alcohol, radiation, genes,
Why do we surgically remove tumours?
surgical removal before they compress other structures
How can cancer spread?
Tumours spread via lympatic and blood drainage systems
Once cancer has spread via blood drainage and/or lymphatic systems, what type of treatment does the patient need?
Systematic (chemotherapy)
What are other forms of radiation besides IR?
Atmospherical radiation, phones EMR
If a drug ends in MAB?
These are all monoclonal antibodies
What is Palliative radiotherapy?
Aims to improve the quality of life by relieving symptoms without causing unacceptable side effects
delivering lower doses in smaller fractions (can be high dose with lung)
What type of patients is palliative radiotherapy good for?
Patients with metastic disease
What are examples of palliative prescriptions?
30 gray in 10 fractions, 25 gray in 5 fractions, 35 gray in 12 fractions
What is the reason for palliative prescriptions?
We want to reduce the amount of time spent at the clinic and reduce their pain, (really good with bone cancer)
How does radiotherapy work?
Ionisation damages DNA or ionises water into more damaging chemical (free radical) which damages DNA
Why wouldn’t you recommend antioxidants during treatment?
They can repair the cancer genes
How is radiotherapy produced?
accelerating an electron into a block of metal, more acceleration produdes more energy
What are the benefits of old cobalt machines? Why are they still in use? (rarely)
3rd world countries, that don’t have access to reliable electricity, tropical countries during storms
They do produce good dose
Why and what type of kilovoltage (kV) is used?
- up to 300kV
- penetrates body most dose at the surface (treats superficial)
Why is Megavoltage (MeV or MV) used?
- 4MeV to 20 MeV
- deposit high dose at depth
- used to treat tumours that are centralised- middle of the body
What energy is usually used for head and neck?
4MV
Energy for thorax?
6MV
energy Pelvis?
10MV or 18MV (QLD doesn’t use 18MV, need proton doors)
What is brachytherapy?
Inserting radioactive source interstially intra-cavity (internal opening cavity of human), stay in patient and deliver dose over time
What is brachytherapy?
Inserting radioactive source interstitially intra-cavity (internal opening cavity of human), stay in patient and deliver dose over time
What does a radiation therapist do?
- Plans radiation therapy
- delivers radiation therapy
- provides support and care
- provides advice about radiotherapy
- Education and research
- major role in multi-disciplinary team
- advocates for the patient
What is the usual patient pathway? (prescription)
- Radiation oncologist councils patients on benefits and negatives of different treatments
- decides on optimal treatment, and prescribes dose energy and overall timing of course
- patient booked for MI
What is the usual patient pathway? (prescription)
- Radiation oncologist councils patients on benefits and negatives of different treatments
- decides on optimal treatment, and prescribes dose energy and overall timing of course
- patient booked for MI
What are important conversations the RT needs to have with the patient on Sim?
Discuss possibility of time lengthen of planned treatment, due to public holidays machine breakdown etc
Patient pathway- localisation?
- involves CT scan, very few use x-rays
- RT performs scan
- images used to identify tumour, OAR
How much extra of the patient do we need to CT scan if we scan a lung tumour patient?
scan from the chin to amout 5cm inferior to lung
We need to scan the entire lung because we need to know entire dose to the normal tissue and lung
Patient Pathway- planning, what is involved?
RT uses specialist software to illustrate the dose distribution in the patient for different combinations of beams
- imaging
- dose planning + calculation
- how to direct IR to tumour
- ensure minimal OAR dose
- ensure critical structures are safe
What is the ‘therapeutic ratio’ why is it important?
consider theraputic ration- Possibility of tumour control, vs possibility of damage to OAR
What is FDG? (used in PET)
Flurodeoxyglycose It is an glucose solution that is a radioactive trace.
This is injected into the patient, has a half life of usually half an hour.
Since tumours use up a lot of energy due to high cell cycle, it accumulates in the cancerous tissues.
What are the problems with MR?
- Patients can be claustrophobic
- patients with certain metallic implants possibly can’t have MR
Patient pathway- treatment, what is involved?
The RT must explain the process and potential side effects, need to explain who you are what you are doing. ESPECIALLY during straighten and level
- Need to position accurately the same way each day
- leave the room, ring the bell, communicate to patient and beam on
- patient observed by CCTV
What is a typical time for patient treatment?
10-15 mins
5-8 weeks
Patient pathway- side effects experienced? how is the RT involved?
Apart from fatigue- erythema, temporary hair loss, diarrhoea, nausea, frequency of urination
