An overview of Radiotherapy Flashcards
What do you use radiotherapy for
- curative intent
- palliative intent
name differences between radiotherapy and chemotherapy
Radiotherapy
- uses X rays
- localised
Chemotherapy
- chemical agents
- not localised
How does the radiotherapy machine works
- Linear acceleration head – high ray of X rays come out of the machine
- Kilovoltage – can take X rays when they are in the clinical position
- Beam generation kit used to generate the high energy X rays
- Fire the electrons at the target – uses a wave guide to accelerate them to the speed of light
- Bended round 270 degrees, hit a tungsten target and sprays out the X rays in an uncontrolled position
- In order to control the x rays the radiation field is shaped by multi leaf – parts of lead that moves out of the field independently, shaped the radiation beam to the target
what does conventional radiotherapy do
- Use a series of fixed fields with a fixed aperture shape that is fixed to the target
what are the types of radiotherapy techniques
- Photons
- Electrons
- Superficial X-Rays
- Brachytherapy
- Radioactive treatments
- Protons.
What are photons
Photons: wave like packets of energy
• Deposit energy when they meet matter.
What is the difference between gamma rays and X rays
- Gamma rays: emitted by radioactive decay.
* X-rays: formed by an interaction of electrons with a nucleus.
What is the grey
• The Gray: the unit of absorbed dose.
What is 1 gray
• 1 Gray: deposit of one joule of (radiation) energy in one kg of matter or tissue.
what does 1 gray exposure cause
• 1 Gray: exposure in cells causes:
o >1000 damage DNA bases
o ~1000 single stranded DNA breaks
o ~40 double stranded breaks.
What are the side effects of radiotherapy
- Depends on the area
- If head and neck – discomfort when swallowing
- Side effects last 3-4 weeks after finishing
- 8 weeks to access a response to treatment
How do you keep the patient still and stable during radiotherapy treatment
- Use a shell
How do you prepare the patient for radiotherapy treatment
- Check ID – photo ID, date of birth and name
- Patient underneath the machine
- Place shell over there head and clip it into place
- Set machine in the right position for treatment
- Tends to last 10-15 minutes
- Have to come back every day sometimes for 3 weeks as an example
What is spinal cord compression
- this is an oncological emergency
- seen in patients who have metastasized to the bone and develop new symptoms such as worsening pain, neurological and mobility effecting
- the bones can crumble and this can put pressure of the spinal cord
What are the symptoms of spinal cord compression
develop pain, sphincter discrepancy or neurological issues
