Physics

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What are X-rays? Name two materials x-rays are absorbed by.
X-rays are high frequency, short wavelength electromagnetic waves
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Name a material that x-rays are transmitted by.
Healthy soft tissue
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What can x-rays cause?
They can cause ionisation and can damage or kill living cells
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What is a charge-coupled device?
CCDs are silicon chips, divided up into a grid of millions of identical pixels. They detect x-rays and produce electronic signals which are used to form high resolution images
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Describe how x-ray images can be formed using photographic film.
X-rays interact with photographic film the same way as light. Formed by the varying intensities of x-ray beam that are transmitted through the film. Where x-rays transmitted, reach photographic plate, turns dark. Leaves white image of denser areas
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Describe how x-rays can be used to treat cancer.
High doses of x-ray will kill living cells. So x-rays used to treat cancer. X-rays focused on tumour using a wide beam. Damage to normal cells can make patient very ill. Damage minimised by rotating x-ray beam keeping tumour at the centre.
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Name 2 medical conditions that x-rays can be used to diagnose.
Bone fractrures and dental problems
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Explain the process of a CT scan.
Patient is put inside CT scanner. X-ray tube emits an x-ray beam whilst rotating around the patient. Detectors on opposite side of scanner measure intensity of transmitted x-rays. Computer uses detected x-rays to generate a 2D image/3D image.
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What precautions can radiographers take to minimise their radiation dose?
Wearing lead aprons, Leaving the room whilst the scans are being done, standing behind a lead screen
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Name two ways in which a patients radiation dose can be minimised.
Lead used to shield areas of the patients body that are not being scanned.
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What is an ultrasound?
Is sound with a frequency above 20,000Hz which is higher than the upper limit of hearing for humans
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How can ultrasounds be generated?
Electrical systems produce electrical oscillations of any frequency which are converted into mechanical vibrations (sound waves)
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What is the formula for working out the distance between boundaries?
S=VxT (where S=distance, V=speed and T=time)
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Name four ways that ultrasound waves can be used in medicine.
Investigating the bllodflow in organs, diagnosing heart problems, checking fetal development, breaking down kidney stones
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How are ultrasound waves used in the pre-natal scanning of a fetus?
Ultrasound waves pass through body, whenever they reach boundary between 2 different media e.g. fluid in womb and skin of fetus, some of wave reflected back and detected. Processed by computer to produce video image of fetus
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How are ultrasound waves used to break down kidney stones?
Kidney stones- hard masses, block urinery tract. Ultrasound beam produces high energy waves which turns stones into sand particles. Passes out of body in urine. Patient needs no surgery, painless
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Are ultrasounds safe? Are x-rays safe? Are CT scans safe?
Ultrasounds- non-ionising, safe. X-rays- ionising, can cause cancer if exposed to high dose, not safe to use on developing babies. CT scans- more x-ray radiation, even more ionising radiation, not taken unless really needed because of radiation dose
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What is the image quality like?
Ultrasound- fuzzy, harder to diagnose conditions. X-rays- clear images of bones and metal but not much else. CT scans- detailed images, diagnose complicated illnesses, 3D imaging used in planning of complicated surgery
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Other cards in this set

Card 2

Front

Name a material that x-rays are transmitted by.

Back

Healthy soft tissue

Card 3

Front

What can x-rays cause?

Back

Preview of the front of card 3

Card 4

Front

What is a charge-coupled device?

Back

Preview of the front of card 4

Card 5

Front

Describe how x-ray images can be formed using photographic film.

Back

Preview of the front of card 5
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