4. Imaging methods and their role in the treatment of tumors Flashcards
Important roles of imaging in treatment of tumors
- early detection and diagnosis
- staging prior to treatment
- evaluation of therapy response
- follow up
- restage the tumor and revise therapy
- tissue guided biopsy
- planning of radiotherapy
Types of imaging
- Anatomical imaging: information about the anatomical and pathological conditions of the tumor
- Functional imaging: information about the functional, metabolic and molecular changes in the tissue
Modalities of Imaging
- Conventional X-ray
- Angiography
- Ultrasound
- MDCT (CT)
- MRI
- Tomosynthesis
- PET/CT
What are the benefits of X-ray?
- easily accessible and cheap
- imaging for lung, bone, breast (and abdomen, GI)
What are the advantages of ultrasound?
- cheap and easy access
- non invasive, non-ionizing, well tolerated
- real-time and flow information
What are the disadvantages of ultrasound?
- lack of complex information
- difficult to evaluate deep tissues and big lesions
- no bone evaluation
- subjective
- technique/personal dependent
What is the clinical application of ultrasound?
- transcutan: abdomen, pelvis, neck, breast, extremities (DVT)
- endocavital, endorectal, endoesophageal, endoscopic
- intraoperative
What are the ultrasound methods?
- gray scale
- doppler
- contrast enhanced (for microbubbles, liver, kidney, and urinary tract tumors)
- elastography (to evaluate elastic properties of soft tissue)
What is the disadvantage of MDCT?
ionizing radiation
What are the advantages of MDCT?
- quick, tolerable, informative
- whole body information
- high spatial and contrast resolution
- volumetric measurement – multiplanar and 3D information
- excellent temporal resolution in contrast enhanced dynamic phases
- good soft tissue resolution when using contrast agent
- best demonstration of bone cortex but not bone marrow
- calcifications (especially in lungs)
What are the advantages of MRI?
- high spatial and high contrast resolution
- best soft tissue resolution on intracranial, perineural spread, head and neck, spine, pelvis, upper abdomen, breast, extremities
- tissue specific information
- flow sensitivity (MR angiography)
- functional imaging
What functional information is gathered from MRI?
- MRSI (spectroscopy): biochemical analysis of molecular products
- diffusion-weighted: detects abnormalities relater to mobility/diffusion of water molecules in living tissues
- dynamic contrast enhancement (CE)
What is the use of tomosynthesis?
renewed, digital tomography for breast and lung
What is PET/CT?
- fusion of PET and CT, used for funtional imaging
- 90% clinical application in oncology
What is the use of PET?
- sensitive to metabolic activity
- detection of FDG tracer (glucose activity)
Imaging method for detection/screening
X-ray, US, CT, MRI, guided biopsy
Imaging method for staging
CT, MRI, PET, guided biopsy (by US/CT)
Imaging method for therapy resonse
CT, MRI, PET, US, X-ray
Imaging method for follow up
US, CT, MRI, X-ray
Imaging method for recurrent tumor/restaging
CT, US, MRI, PET
