What are the conventional diagnostic modalities?
Endoscopy and biopsy
What is barium studies?
- Barium sulphate is a radio-opaque contrast used for outlining the gastro-intestinal tract.
- The high atomic number of barium absorbs more x-ray photons than surrounding tissues.
- Barium appears white on the radiograph.
What are the different types of barium studies?
- Barium swallow and meal - oesophagus, stomach and duodenum.
- Barium follow-through or small bowel study - small bowel
- Barium enema - large bowel
What is the radiation dose in barium studies?
- Barium meal =1.5 mSv
- Barium enema = 7.0 mSv
When do you use cross-sectional imaging?
- CT, MRI & PET
- Initial diagnosis and staging of disease
- Monitoring response to treatment
- Evaluation of residual mass after treatment
- Recognition of complications of treatment
- When there is concern for disease relapse
What is computed technology?
- X-rays produce a digital image of a slice of tissue, usually in an axial plane using computing to create the image
Name the types of contrast agens used in CT imaging?
Oral - dilute iodine based contrast (gastrografin) can be given to outline the gastrointestinal tract
Intravenous - iodine based contrast (Omnipaque) injected into the veins to demonstrate blood vessels or the vascularity of different tissues.
Which two stages is CT imaging used in cancer?
Diagnosis i.e lung tumour and pancreatic tumour
Staging : assess local spread e.g. lymph nodes or assess distant spread e.g. liver, lung, bone or brain metastase
What is Magnetic Resonance Imaging?
Strong magnetic field aligns protons (H+) in the body in one direction
Radiofrequency pulse displaces protons and images created by displaying time taken for protons to “relax” back to the original alignment
Name some features of MRI?