Flashcards in Imaging Deck (57)
Reasons for Imaging in the Management of Cancer
Making the diagnosis
Response to treatment
Types of Imaging in Cancer
What are X-rays good for?
X-rays not good for
What do x-rays rely on?
Imaging for Bone Lesions
What are we looking at on x-rays for oncology imaging?
Nature of the bone matrix
Interface of lesion & bone
What part of bone?
Benign vs. malignant
Define Benign Bone Lesions
No cortical destruction
No periosteal reaction
What are CT scans best for evaluating?
Subtle bone changes
What are MRI scans best for evaluation of?
Soft-tissue & infiltrative marrow lesions
Define Latent Bone Lesions
Surrounded by reactive cortical rim
Define Active Bone Lesions
Easily discernible transition without reactive rim
Define Aggressive Bone Lesions
Broad infiltrating border
Continuous X-rays used to obtain real time moving images of internal structures
Define CT Scan
X-rays taken in several planes are computer processed to show images in multiple slices: AP, lateral, sagittal, x-section & even as 3D images
Advantages of CT Scancs
Differentiate structures of close physical density
Eliminates superimposition of organs
Show calcified & hemorrhagic lesions
Show in multiple planes or even as a 3D image
Advantages of CT Scans in Neoplastic Disease
Very good in the abdomen for staging
Very good for evaluation of masses in the chest
Can do virtual colonoscopy
Most intracranial neoplasms are visible
Disadvantages of CT Scans
Risk of cancer
Contrast: allergic reactions, anaphylaxis, nephropathy
Define Pancoast's Tumor
Extension of tumor at apex of the lung involving C8, T1, T2 nerves & possible destruction of ribs
Presentation of Pancoast's Tumor
Shoulder pain radiating in the ulnar direction
Done with CT
Requires bowel prep
No sedation needed
Not as sensitive as colonoscopy
Can't do biopsies
Uses low energy X-rays to generate images
Needs breast examination
Further mammography for confirmation
Ultrasound for better definition
MRI with gadolinium- implants very dense
Needle/surgical biopsy may be recommended
Tissue diagnosis key
What do nuclear scans measure?
Bone metabolism or remodeling
Radio-isotope injected IV
3 hours later, the patient is scanned
Provides 2D image
Half material goes to the bones
Eliminated through the kidneys
Show increased metabolic activity or increase blood flow
Assess activity or known lesions
Find unknown lesions
MM cold scan until cortical disruption occurs
What does PET stand for?
Positron emission tomography
What can a PET be combined with?
When are PET scans especially useful?