An overview of Radiotherapy Flashcards

1
Q

What do you use radiotherapy for

A
  • curative intent

- palliative intent

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2
Q

name differences between radiotherapy and chemotherapy

A

Radiotherapy

  • uses X rays
  • localised

Chemotherapy

  • chemical agents
  • not localised
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3
Q

How does the radiotherapy machine works

A
  • 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
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4
Q

what does conventional radiotherapy do

A
  • Use a series of fixed fields with a fixed aperture shape that is fixed to the target
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5
Q

what are the types of radiotherapy techniques

A
  • Photons
  • Electrons
  • Superficial X-Rays
  • Brachytherapy
  • Radioactive treatments
  • Protons.
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6
Q

What are photons

A

Photons: wave like packets of energy

• Deposit energy when they meet matter.

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7
Q

What is the difference between gamma rays and X rays

A
  • Gamma rays: emitted by radioactive decay.

* X-rays: formed by an interaction of electrons with a nucleus.

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8
Q

What is the grey

A

• The Gray: the unit of absorbed dose.

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9
Q

What is 1 gray

A

• 1 Gray: deposit of one joule of (radiation) energy in one kg of matter or tissue.

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10
Q

what does 1 gray exposure cause

A

• 1 Gray: exposure in cells causes:
o >1000 damage DNA bases
o ~1000 single stranded DNA breaks
o ~40 double stranded breaks.

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11
Q

What are the side effects of radiotherapy

A
  • 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
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12
Q

How do you keep the patient still and stable during radiotherapy treatment

A
  • Use a shell
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13
Q

How do you prepare the patient for radiotherapy treatment

A
  • 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
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14
Q

What is spinal cord compression

A
  • 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
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15
Q

What are the symptoms of spinal cord compression

A

develop pain, sphincter discrepancy or neurological issues

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16
Q

what is the treatment of spinal cord compression

A
  • Have to have an MRI of scan and helps them decide best course of therapy – neurosurgery or radiotherapy
  • Radiotherapy – given as a course of treatment, can be 1 course or 5 courses over a 5 day plan
17
Q

What do the fractions mean

A
  • the number of times they have dose

so 15 fractions means 15 times