Unit 3 - Xrays and Ultrasound

Question 1

What type of wave lengths do X-rays have and what type of waves are they?

Answer 1

X-rays are high frequecny, short wavelenghth elevtromagnetic waves

Question 2

What size are X-rays

Answer 2

Similar size to atoms (10-10M)

Question 3

With what do X-rays classification overlap with?>

Answer 3

Gamma rays

Question 4

How to X-rays affect photographic film?

Answer 4

The same way as light (create fog)

Question 5

What do x-rays pass through and what are they absorbed by?

Answer 5

X-rays pass through healthy tissues and are absorbed by denser materials like bone and metal

Question 6

How are X-rays formed electronically?

Answer 6

By using charge-coupled devices (CCD’s)

Question 7

Give an advantage of using CCD

Answer 7

You can review it straight away (as apose to photographs which takes time to develop and they’re not always developed properly)

Question 8

How do CT scans work?C

Answer 8

CT scans use X-rays (from different angles) to produce high resulution images (with lots of detail) of soft and hard tissue

Question 9

Why do CT scans use lots more X-rays than a normal X-ray scan?

Answer 9

Soft tissue can absorb a small amount of X-ray radiation. Ct scans use lots of X-rays to distinguish between tiny variations in tissue density

Question 10

What is the disadvantage of CT scans?

Answer 10

High radiation dose, highly ionising​ - this can cause DNA mutations (which can lead to a risk of cancer)

Question 11

Why can X-rays be used to treat cancer?

Answer 11

X-rays can cause ionisation, meaning a high dose of x-rays will kill living cells.

Question 12

How do X-rays treat cancer (process)

Answer 12

• The x-rays are focussed on the tumor using a wide beam
• The beam is rotated round the patient with the tumor at the centre
• This minimises exposure of normal healthy cells to radiation, and reduces the chance of damaging the rest of the body

Question 13

Give 3 ways that radiographers can minimise their dose of radiation

Answer 13

• Wear lead aprons
• Stand behind a lead screen
• Leave the room whilst the scan is bieng done

Question 14

Definition of Ultrasound

Answer 14

Ultrasound is the name given to sounds waves that hae frequencies greater tha 20,000Hz

Question 15

What is the human hearing range?

Answer 15

20-20,000Hz

Question 16

Give 5 uses of ultasound

Answer 16

• Scanning foetuses during pregnancy
• Investigating liver/heart problems
• Breaking down kidney stones and stones elsewhere
• Measuring the speed of blood flow in the body
• Cleaning jewellery

Question 17

How does ultasound imaging work?

Answer 17

1. The ultrasound is sent into the patients body
2. At each boundry between tissues/organs, some of the ultrasound is relected
3. The depth of each layer is calculated using the time taken for each reflected wave to return
4. The reflected waves (echoes) are usually processed to produce a picture of the inside of the body on a screen

Question 18

Why is jel used during an ultrasound?

Answer 18

To allow everything to be in contact, if there was air gaps over 90% of the waves wouldn’t be reflected and a very weak image produced

Question 19

Why do high frequencies give you more detail?

Answer 19

They have a short wavelength

Question 20

What are kidney stones?

Answer 20

A build up of salts, that resonate

Question 21

Kidney stones can be removed by operation, but what are the disadvantages of this?

Answer 21

• Costs
• Risk to the patient
• Risk of infection

Question 22

How is ultrasound used to break down kidney stones?

Answer 22

A high powered ultrasound wave is used to break down the kidney stones (as well as other stones) as the stones vibrate until the shake themselves apart

Question 23

Comparing Ultrasound, X-ray and CT scans: Are they safe?

Answer 23

• Ultrasound is non-ionising (safe)
• X-rays are ionising.

They can cause cancer when exposed to a high dose, not safe to use on developing babies

• CT Scans are highly ionising and are only used when they’re really needed because of the increased radiation dose

Question 24

Comparing Ultrasound, X-ray and CT scans: Image quality?

Answer 24

• CT Scans produce detailed images and can be used to diagnose complicated illnesses (the high resolution can make them easier to diagnose)

High quality 3D images can also be used to plan complicated surgery

• X-ray’s produce clear images of bones and metal, however not a lot else
• Ultrasound images are typically fuzzy and can therefore make it harder to diagnose some conidtions using these images