Fundamentals of Contouring
has partnered with the Radiation Oncology Education
Collaborative Study Group (ROECSG)
to bring together contouring resources for trainees
. Please do not hesitate to contact us (email@example.com
) with questions or suggestions!
- Dr. Erin Gillespie, Chief Resident at UC San Diego, eContour Co-Founder and ROECSG Member
- Dr. Jill Gunther, Resident at MD Anderson Cancer Center, ROECSG Member
- Grant Larson, BS, Medical Student at University of North Dakota, eContour Contributor and ROECSG Member
- Neil Panjwani, BSE, Medical Student at UC San Diego, eContour Co-Founder and ROECSG Member
How to Contour
See Help to review all of the functions of eContour as your reference resource.
Interactive Training Modules
Tips and Tricks
- It is often best to start with contouring the OARs (check they are accurately delineated if a dosimetrist contoured them for you!)
- start with GTV = gross tumor volume (can be primary tumor and/or lymph nodes), if present*
- *NOTE: most post-op cases will not have gross tumor remaining
- then contour CTV = clinical target volume
- includes direct microscopic extension of primary tumor (apparent normal tissue on imaging) - can be created by an automatic expansion (aka margin, often 5-10mm), though usually "carving out" bone or air that is not at risk of tumor invasion (but this depends on tumor type)
- include lymph node regions at risk
of tumor spread - sometimes called "elective" lymph node regions if no
nodes are involved with tumor in that region (called "levels" in the
- sometimes divided into multiple subdivisions (CTV1, CTV2,
etc) in order to allow differential margins for internal or physiologic
organ motion (ITV) or setup error (PTV)
- lastly PTV = planning target volume
- usually an automatic expansion based on predicted error in daily setup which depends on:
- immobilization devices (ie H&N masks hold skull much more reliably than vac lock bag for pelvis)
- extent of daily imaging (ie daily CBCT will be more exact than a weekly MV port film)
- NOTE: daily setup starts with lasers and tattoos! ....then adjustments are made from imaging...
- "Window/Level" the CT scan --> treatment planning systems have pre-set ranges that optimize your view based on the tissue of interest.
- Select "abdomen" or "pelvis" or "mediastinum" for best soft tissue contrast (fat/muscle/vessels)
- Select "bone" (highest density) to view abnormalities within the bone or skull base
- Select "lung" (lowest density) to view lung parenchyma
- NOTE: You can always switch between them while contouring to
determine which window/level allows you to best delineate your target.
- Use your 3D views --> align your sagittal and coronal images over your contour to check your contour in all three dimensions.
- Fused images - diagnostic images that have been fused to the simulation CT to help contour delineation.
- MRI is most useful for differentiating different soft tissues
- PET is most useful for identifying abnormal lymph nodes - be
sure to correlate with tissue on the CT scan to ensure the size of your
area of interest, since PET windowing can significantly affect the
apparent size of the tumor.
- MORE: For case-specific tips, see Modules above and "Pearls" within each eContour case
- NCCN Clinical Practice Guidelines in Oncology (NCCN.org)
- expert consensus recommendations for work-up and management organized
by disease site including reference to studies that guide the standard
of care (FREE to register)
- Radiographic Anatomy
- MORE: Visit the ROECSG website: General Resources
- Berman AT, Plastaras JP, Vapiwala N. "Radiation Oncology: a Primer for Medical Students" J Canc Educ 2013. Link to PubMed
- Terezakis S et al, "What the diagnostic radiologist needs to know about radiation oncology." Radiology. 2011 Oct. Link to PubMed
- Osvarek J et al. "Medical Student Knowledge of Oncology and Related Disciplines: a Targeted Needs Assessment" J Canc Educ 2015. Link to PubMed