Session 2 - Medical Imaging Flashcards
Name 6 common medical imaging techniques.
X-rays Ultrasound Medical Resonance Imaging - MRI Computerised Tomography Scanning -CT Positron Emission Tomography - PET Fluoroscopy
Why is a thin sheet of metal placed in front of the X-ray tube to act as a filter when performing a high energy X-ray?
This absorbs the low energy X-rays that would be absorbed by the body and have no use thus would otherwise unnecessarily increase the radiation dose.
What form of imaging is used to produce a CT scan?
Most often X-Ray but can also PET and Single-Photon Emission computed tomography (SPECT)
What are PET scans used for and how is this done?
They are used to observe metabolic processes in the body. This is done by detecting the emission of gamma rays from from positron-emitting radionuclides. Such as fluorine-18, which is introduced to the body on a biologically active molecule such as glucose.
Glucose is used in rapidly metabolising organs like tumours or cancers
What is Spina Bifida? What imaging technique Is usually used of identify it?
A condition where the spinal cord doesn’t develop properly in the womb and as such the membranes around the cord can protrude out. This is usually identified using ultrasound as this as no adverse effects on the developing foetus unlike x-ray.
What colour is water in a t1 weighted MRI?
Water is black
Why is obesity a major problem for the use of MRIs?
They don’t fit.
What is radiology?
The science of medical imaging used to diagnose or sometimes treat diseases within the body using ionising radiation.
Name some common contrasts used in fluoroscopy.
BaSO4, Barium Sulphate - used for the GI tract, taken orally or rectally
Iodine - in different forms given by oral, rectal, vaginal inter-arterial or intravenous routes. Can show dynamic processes such as peristalsis and blood flow.
Air can be used sometimes in the GI tract and sometimes CO2 in the venous system in these cases the x-ray is attenuated less than the surrounding tissues
What is nuclear medicine?
The administration of radio-pharmaceuticals labelled with a radioactive tracer into the patient. These substances consist of material with affinity for specific body tissues.
Define a contrast media?
A substance that is used in radiography to increase the contrast of an image. This is mainly by increasing the attenuation of the radiation but it could also be by reducing the attenuation such as the case when air is used.
