Imaging Techniques

Who discovered the x-ray in 1895?

Lossy compression file formations should never be used to store medical images.

With what piece of apparatus were x-rays discovered?

Why is iodine a good contrast agent for x-ray imaging?

X-rays are produced when high speed electrons strike a target material. The energy of these electrons can be converted to what, in terms of what is useful in medicine?

Which factors of tissues allow us to distinguish between different tissues on an x-ray image?

Tissues who are more attenuating of x-rays appear brighter on x-rays (i.e. bones are highly attenuating so appear bright white)

Which generation of CT scan do modern systems use?

Fill in the blanks to give the type of ionising radiation based off the property. [blank_start]Alpha[blank_end] radiation is stopped by paper. [blank_start]Beta[blank_end] radiation is not stopped by paper but is stopped by plastic. [blank_start]Gamma[blank_end] radiation is not stopped by paper or plastic but is stopped by concrete/steel/lead.

Alpha decay occurs in natural radioactive elements heavier than lead (i.e. having a relative mass of over 81)

In beta-minus decay, what does a neutron break down into?

In beta-minus decay, the atomic number and mass both increase by 1.

In beta-plus decay, a proton breaks down into what?

Why is alpha radiation not suitable for medical imaging?

What happens when a positron and an electron meet?

In isomeric transition, the mass, atomic number and charge of the nucleus all remain the same.

Radioactive isotopes with long half lives are not suitable for use in medical imaging.

Which radioactive isotope do we commonly use in medical imaging due to its half life of around 6 hours and its ability to be made in a lab?

Why can we use the 18F isotope to monitor metabolism in tissues?

What type of radiation does the 18F isotope emit?

Fill in the blanks to describe the physics of MRI scanning. Protons have the physical property of [blank_start]spin[blank_end] - they spin on their axes oriented in different directions. When placed inside a magnetic field, the protons align and become [blank_start]parallel[blank_end]. Some protons will spin in a [blank_start]north-south[blank_end] direction, others in a south-north direction. In the MRI scanner, a second electromagnet flips the protons off their axes, usually by [blank_start]90[blank_end] degrees. The [blank_start]frequency[blank_end] of the coil must exactly match the [blank_start]frequency[blank_end] at which the protons are spinning. When we turn off the second electromagnet and the proton returns to its [blank_start]resting[blank_end] spin and releases [blank_start]radio[blank_end] signals which can be detected. Different tissues have different densities of [blank_start]water[blank_end] so take different lengths of time to return to rest - these relaxation time differences form contrasting images.

Why do MRI images not show bone?

Fill in the blanks below to describe the principles of ultrasound imaging. A short ultrasound pulse is emitted and a detector 'listens' for a [blank_start]reflected[blank_end] pulse. The time between emitting a pulse and receiving a response tells us how far away the pulse was when it was [blank_start]deflected[blank_end]. The energy of the pulse tells us how much the energy has [blank_start]depleted[blank_end] in the tissue - the properties of the tissue determine this.

What did Ansell and Rotblat do in 1948?

Langevin invented the hydrophone to detect icebergs using pulse-echo physics ib 1915 following the Titanic disaster.