Imaging in Cancer Flashcards
<p>What are different kinds of imaging that can be used to diagnose cancer?</p>
<p>Plain radiographs</p>
<p>Barium studies</p>
<p>CT</p>
<p>MRI</p>
<p>PET</p>
<p>What are conventional cancer diagnosis methods?</p>
<p>Endoscopy and biopsy</p>
<p>Barium examination</p>
<p>What is a radio-opaque used from outlining the gastro-intestine tract?</p>
<p>Barium sulphate</p>
<p>Why is barium used to outline the GI tract?</p>
<p>High atomic number absorbs more X-rays than surrounding tissue and appears white on radiograph</p>
<p>What chance does barium have of developing fatal malignancy after 10 years latent perioid?</p>
<p>1:2000</p>
<p>What are different kinds of cross sectioning imaging?</p>
<p>CT</p>
<p>MRI</p>
<p>PET</p>
<p>What can cross sectioning imaging be used for?</p>
<p>Initial diagnosis</p>
<p>Staging of the disease</p>
<p>Monitoring response after treatment</p>
<p>Evaluation of residual mass after treatment</p>
<p>What does CT stand up for?</p>
<p>Computed tomography</p>
<p>What happens during a CT scan?</p>
<p>X-rays produce a digital image of a slice of tissue</p>
<p>What is hounsfield unit?</p>
<p>Attenuation value of voxels are expressed as a CT number which relates to the attenuation value to that of water (ranges from -1000 to +3000</p>
<p>What are some common hounsfield values?</p>
<p>Air -1000</p>
<p>Lung -700</p>
<p>Fat -100</p>
<p>Water 0</p>
<p>Blood +40</p>
<p>Muscle +40</p>
<p>Calcium +150</p>
<p>Bone +700 to +3000</p>
<p>What is a voxel?</p>
<p>A value on a grid in a 3D space</p>
<p>What are contrast agents?</p>
<p>Substances used to enhance the visibility of internal structures in X-ray based imaging</p>
<p>What are the two kinds of contrast agents?</p>
<p>Oral</p>
<p>Intra-venous</p>
<p>What do oral contrast agents do?</p>
<p>Outline the GI tract</p>
<p>What do intra-venous contrast agents do?</p>
<p>Show blood vessels and vascularity of different tissues</p>
<p>What are contrast agents usually made of?</p>
<p>Usually iodine based, oral ones are diluted and known as gastrografin and IV ones are known as omnipaque</p>
<p>What are oral contrast agents known as?</p>
<p>Gastrografin</p>
<p>What are IV contrast agents known as?</p>
<p>Omnipaque</p>
<p>What do scans show to diagnose and stage a tumour?</p>
<p>Position of tumour</p>
<p>Depth of tumour</p>
<p>Relationship to adjacent structures</p>
<p>Involvment in regional lymph nodes</p>
<p>Presence of distant metastasis</p>
<p>What are different scans used for?</p>
<p>Different kinds of cancers</p>
<p>What kinds of cancers are CT scans used for?</p>
<p>Lung</p>
<p>Pancreatic</p>
<p>Renal</p>
<p>Adrenal</p>
<p>Retroperitoneal</p>
<p>Brain</p>
<p>What CT scans have the highest equilvalent dose and what value is this?</p>
<p>CT scans of the abdomen and pelvis which have an equilvalent dose of 10mSv</p>
<p>What should be considered when deciding if a scan is required?</p>
<p>Ensure examination is necessary</p>
<p>Adequate clinical information is essential for appropiate protocol</p>
<p>Avoid repeat examination</p>
<p>What does MRI stand up for?</p>
<p>Magnetic resonance imaging</p>
<p>How do MRIs work?</p>
<p>1) Magnetic fields align protons in the body in one direction</p>
<p>2) Radiofrequency pulse displaces protons and images are created displaying the time they take to reurn to their original position</p>
<p>What is MRI often used for?</p>
<p>Excellent soft tissue detail</p>
<p>Vessels can be demonstrated</p>
<p>Brain, spine and musculoskeletal</p>
<p>Abdomen and pelvis</p>
<p>Cardiac imaging</p>
<p></p>
<p>What are disadvantages of MRI?</p>
<p>Claustrophobic and noisy</p>
<p>Motion artefact</p>
<p>Cannot image patients with pacemakers and other electronic implants</p>
<p>What contrast agent can be used in an MRI and what does this do?</p>
<p>Gadolinium DTPA (intravenous agent) which changes local magnetic fields and so alters the tissue signal</p>
<p>What is screening used for?</p>
<p>To diagnose at an earlier stage before symptoms begin, making it more curable</p>
<p>What are the 3 NHS screening problem?</p>
<p>Breast</p>
<p>Bowel</p>
<p>Cervix</p>
<p>What must happen for screening to be useful?</p>
<p>Condition should be an important health problem</p>
<p>Should be a latent stage of disease</p>
<p>Should be a test or examination for the disease</p>
<p>Test should be acceptable to the population</p>
<p>Should be a treatment for the disease</p>
<p>What should screening do?</p>
<p>Detect disease at earliest stage</p>
<p>Cause no harm</p>
<p>High sensitivity and specificity</p>
<p>Benefit to individual and population outweigh the cost</p>
