Fundamentals of Contouring

eContour 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 (support@econtour.org) 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

Prostate Fossa (PDF)
- Test case DICOM image files available for download to your treatment planning system from the MedEdPORTAL (FREE)
- Gunther JR et al. "A Prostate Fossa Contouring Instructional Module: Implementation and Evaluation" J Am Coll Radiol 2016. Link to PubMed
Intact Prostate (PDF)
Rectal Cancer (PDF)
Cervical Cancer Module

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!)
GTV/CTV/ITV/PTV

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 H&N)

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

Resources

Management

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

HeadNeckBrainSpine.com - interactive neuroradiology anatomy (FREE)
Radiopaedia.org - wiki-based collaborative Radiology resource (FREE)
e-Anatomy (www.imaios.com) - interactive radiographic anatomy (subscription required)

Contouring

Nancy Lee's Textbook "Target Volume Delineation for Conformal and IMRT" (2015) (purchase on Amazon)
RTOG Contouring Atlases

MORE: Visit the ROECSG website: General Resources

Abbreviations and Definitions

3D-CRT = 3-dimensional conformal radiation therapy
4D-CT = 4-dimensional computed tomography
ALND = axillary lymph node dissection
AP = anterior to posterior
AP/PA = opposing radiation fields in 2D or 3D-CRT in which an one beam treats anterior-to-posterior and a second beam treats posterior-to-anterior in relation to the patient
BED = biologically equivalent dose --> check out "BED calc" for iPhone or "RBApp" for Android
BID = latin for "bis in die", which means twice per day; in radiation therapy, usually in regards to two fractions separated by at least 6 hours
BOT = base of tongue
CBCT = cone beam computed tomography
cGy = centigray (unit measure of radiation therapy; 100cGy = 1Gy)
"chemo-RT" = shorthand for concurrent chemotherapy and radiation therapy
cm = centimeter
CR = complete response (cCR = clinical; pCR = pathologic)
CT = computed tomography
CTV = clinical target volume
"cuff" = vaginal apex; often used as shorthand to describe where the top of the vagina is sutured together following a hysterectomy
EBRT = external beam radiation therapy
EBV = Epstein-Barr virus
ECE = extracapsular extension
EQD2 = equivalent dose in 2Gy fractions
EUA = exam under anesthesia
"F" = in Assessment this is shorthand for "female"
FOM = floor of mouth
FVC = false vocal cord
GTV = gross tumor volume
Gy = gray (unit measure of radiation therapy)
H&N = head-and-neck
HDR = high-dose rate
HL = Hodgkins Lymphoma (formerly Hodgkins Disease)
HPV = human papilloma virus
HPX = hypopharynx
IFRT = involved-field radiation therapy
IGRT = image-guided radiation therapy
IJV = internal jugular vein
IMRT = intensity-modulated radiation therapy
IM = internal mammary
INRT = involved-node radiation therapy
"ipsi" = shorthand for "ipsilateral"
ISRT = involved-site radiation therapy
ITV = internal target volume
IV contrast = intravenous
"kv" = shorthand for "kilovoltage X-ray"
L = left
LC = local control
LDR = low-dose rate
LN = shorthand for "lymph nodes"
LRC = local-regional control
LT = left
LVI = lymphovascular invasion
LVSI = lymphovascular space invasion
"M" = in Assessment this is shorthand for "male"
"mgn" = shorthand for "margin"
mm = millimeter
MRI = magnetic resonance imaging
"N+" = shorthand for "lymph node positive"
"neg+ = shorthand for "negative"
NPX = nasopharynx
"obs" = shorthand for "observation," which indicates no further therapy
OPX = oropharynx
PA = para-aortic OR posterior-to-anterior, depending on the context
PET = positron emission tomography
PNI = perineural invasion
PTV = planning target volume
QA = quality assurance
R = right
RCT = randomized controlled trial
RLL = right lower lobe
RML = right middle lobe
RP = retropharyngeal (usually in reference to lymph nodes in this area)
RT = radiation therapy OR right, depending on the context
Rx = prescription
"s/p" = shorthand for "status post"
SABR = stereotactic ablative radiation therapy (synonymous with SBRT)
SBRT = stereotactic radiation therapy (synonymous with SABR)
SCC = squamous cell carcinoma
SCV = supraclavicular area (located in level IV cervical neck)
SI joint = sacroiliac joint
SIB = simltaneous integrated boost
SLNB = sentinel lymph node biopsy
SRS = stereotactic radiosurgery
T1 = T1-weighted MRI sequence
T1+C = T1-weighted MRI sequence post-contrast (after IV contrast delivered)
T2 = T2-weighted MRI sequence
TAH/BSO = total abdominal hysterectomy/bilateral salpingo oopherectomy
TLD = thermoluminescent dosimeter
TVC= true vocal cord
VB = vaginal brachytherapy
"y/o" and "yo" = shorthand for "year old"

Organizations, Journals and Databases

ABS = American Brachytherapy Society
ACR = American College of Radiology
ACRO = American College of Radiation Oncology
ACS = American Cancer Society
AJCC = American Joint Committee on Cancer --> check out the FREE "TNM Cancer Staging App"
Alliance = a new group which includes ACOSOG, CALGB, and NCCTG
ASCO = American Society of Clinical Oncology
ASTRO = American Society for Therapeutic Radiation and Oncology
CALGB = Cancer and Leukemia Group B
EORTC = European Organization for Research and Treatment of Cancer
FIGO = International Federation of Gynecology and Obstetrics --> organization generates staging in gynecologic cancers that applies to international community with limited imaging modalities (staging summary)
GOG = Gynecologic Oncology Group
ICRU = International Commission of Radiation Units and Measurements
ILROG = International Lymphoma Radiation Oncology Group
IJROBP = International Journal of Radiation Oncology*Biology*Physics (aka "the Red Journal")
NCCN = National Cancer Care Network (alliance of 27 cancer centers that develops national clinical practice guidelines in oncology)
NCDB = National Cancer Data Base (population-based database)
NCI = National Cancer Institute
NRG = NRG Oncology is a new group representing NSABP/RTOG/GOG
NSABP = National Surgical Adjuvant Breast and Bowel Project
PRO = Practical Radiation Oncology (journal publication)
RTOG = Radiation Therapy Oncology Group
SEER = Surveillance, Epidemiology, and End Results (population-based database)
SWOG = Southwestern Oncology Group

Interactive contouring guidelines for the busy radiation oncology professional

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