Role of CT scan in carcinoma cervix Contouring Guidelines forCarcinoma Cervix (3DCRT/IMRT) Normal Tissue Delineation (RTOG

1. IMAGING & ITS ROLE IN FEMALE
GENITAL ORGANS

2. Radiological imaging.
• XRAY
• ULTRASOUND
• CT SCAN
• MRI
• PET CT SCAN

3. X-ray female pelvis

4. Field borders: AP-PA fields
Superior border
• At the L4-5 space to include external & internal iliac L.N.
• extended to the L3-4 space if common iliac nodal
coverage is indicated
• . extended to the T11-12 space if paraaortic coverage is
indicated
Inferior border
• at inferior border of the obturator foramen.
• For vaginal involvement:3cm below the lower most
extent of disease
Lateral borders
• 1.5 - 2cm margin on the widest portion of pelvic brim

5. Field borders : lateral field
Anterior margin
• vertical line to the anterior edge of pubic
symphysis to cover external iliac lymph nodes
Posterior margin
• at S2 – S3 junction
• extend to sacral hollow in patients with advanced
tumours to cover uterosacral ligaments, cardinal
ligaments & presacral lymph nodes
• Superior & inferior margins
• same as that for AP/PA Fields

6. Field borders: AP-PA fields Field borders : lateral field

7. ULTRASOUND ABDOMEN & PELVIS
• Routine Use:
• to detect liver Mets, ascites or abdominal lymphadenopathy.
• Give information about the status of kidneys & ureter (HUN if any)
• Can tell about any associated benign pelvic pathology, uterine
collections etc
• US has limited role in evaluating the size and local regional extent of
the tumour
• in early stages :USG may fail to detect any malignancy
• Eventually, with disease progression, the tumour mass may appear
as a hypoechoic or isoechoic region with undefined margins.

9. CT scan.
• CT Scan: CT is the imaging modality that is most commonly used in
clinical practice to evaluate the extent of spread malignancy
• The oral, rectal, or intravenous administration of contrast material is
necessary for optimal CT evaluation (unless a contraindication exists).
• CT provides diagnostic information about the
• the primary tumour.
• enlarged lymph nodes, and
• presence of metastases,

10. Role of CT scan in carcinoma cervix
• CT can demonstrate pelvic side wall extension,
• ureteral obstruction,
• advanced bladder and rectal invasion,
• adenopathy, and
• extrapelvic spread of disease
• CT can also be used to guide biopsy of enlarged nodes, plan radiation
therapy ports, and monitor patients for tumor recurrence

11. • The limitations of CT have been lack of consistent visualization of the
primary tumor and inaccuracies in detection of parametrial invasion
• For identification of stromal and parametrial invasion, MR imaging
has been shown to be superior to CT
Role of CT scan in carcinoma cervix

12. MRI
• MRI is frequently used now for the initial assessment of the tumour
and local extension
• Advantages of MRI over CT scan is
• better soft tissue contrast
• superior imaging resolution
Currently MRI Is The Investigation Of Choice For Staging Gynaecological
Malignancy

13. Positron emission tomography (PET)
• Limited role
• Can detect early metastatic disease
• some value relative to conventional imaging methods for the
detection of nodal metastatic disease and recurrent cervical cancer,

14. NORMAL RADIOLOGICAL ANATOMY

15. 1. Aorta.
The aorta continues inferiorly into the lower abdomen and
pelvis, bifurcating into the common iliac arteries in front of the
4th lumbar vertebra
(2) Inferior Vena Cava
The inferior vena cava is a large vein that returns blood from
the blood in the lower part of the body. It is a reservoir for the
common iliac, lumbar, right gonadal, renal, right adrenal, and
hepatic veins.
(3) Ureter
The ureter is a tubular structure that receives urine from the
kidney and delivers it to the urinary bladder.
(4) Left Kidney
The left kidney is usually slightly higher than the right
kidney. The left renal vein is long and crosses the aorta
anteriorly to reach the left kidney.
CONTRAST ENHANCED CT
SCAN ABDOMEN AT LEVEL OF
L2 VERTEBRA

16. (6) Cecum
The cecum is the first part of the large intestine. It is about 7
cm. in length. It is located in the right lower quadrant, below the
ascending colon.
(7) Descending Colon
(5) Small Bowel
The small intestine is the longest part of the gastrointestinal
tract, usually measuring 6-7 meters. On this cross sectional
image, the small bowel is identified by white coloration due to
filling of the barium contrast agent.
CONTRAST ENHANCED CT SCAN ABDOMEN
AT LEVEL OF L2 VERTEBRA

17. (8) Psoas Muscle
This is a muscle that runs from the transverse
processes of the lumbar vertebrae to attach to the lesser
trochanter of the femur
(9) Erector Spinae Muscle
This is a large muscle located on each side of the spinal
column
(10) Rectus Abdominus Muscle
This muscle is considered the principle muscle of the
anterior abdominal wall and runs vertically from the
xiphoid process to the pubic symphysis and pubic crest
(11) External Oblique Muscle
(12) Internal Oblique Muscle
(13) Tranversus Abdominus Muscle
(14) Quadratus Lumborum Muscle
(15) Vertebra (Body)
(16) Vertebra (Spinous Process)
CONTRAST ENHANCED CT SCAN
ABDOMEN AT LEVEL OF L4
VERTEBRA

18. (17) Common Iliac Arteries
These vessels are the continuation of the abdominal aorta after it
bifurcates in the abdomen. The right and left common iliacs then
give rise to the internal and external iliacs in the pelvis.
(17a) Common Iliac Veins
The common iliac veins converge to form the inferior vena
cava. The two veins are located posterior and to the right of their
counterpart common iliac arteries. The two common iliac veins are
formed by the internal and external iliac veins which drain the
blood from the pelvis and lower extremity.
(19) External Iliac Vessels
This is one of the two bifurcations of the common iliac as it
descends into the pelvis.
CONTRAST ENHANCED CT SCAN
ABDOMEN AT LEVEL OF L4
VERTEBRA

19. (20) Common Femoral Artery and Vein
The common femoral artery is a continuation of the
external iliac vessels below the inguinal ligament.
CONTRAST ENHANCED CT SCAN PELVIS

20. (23) Iliacus Muscle
This is muscle is located lateral to the psoas major
muscle and attaches to the body of the femur below the
lesser trochanter. It originates from the iliac crest, iliac
fossa and ala of the sacrum.
(24) Gluteus Maximus Muscle
(25) Gluteus Medius Muscle
(26) Gluteus Minimus
Muscle
(27) Sacrum
This bone if formed by the five sacral vertebral that are
fused together to form a wedged shape bone that functions to
supports the pelvis

21. (28) Urinary Bladder
This is a hollow muscle which functions to hold urine. In
adults it is located posterior and superior to the pubic bones An
adult bladder is located in the pelvis but it extends into the
abdomen when it is full of urine.
(30) Rectum
This is the end and last part of the colon. It is located between
the sigmoid colon and the anus. In females the rectum is located
posterior to the vagina and uterus..
(34) Piriformis Muscle
This pear shaped muscle is located in the posterior pelvis. It
originates from the 2nd through 4th sacral segments and
inserts on the greater trochanter of the femur
(29) Sigmoid Colon
This is the end of the intestine located between the
descending colon and the rectum.

22. (42) Symphysis Pubis
This is a tough cartilage that joins the two bodies of the two
pubic bones.
(36) Femoral Head
The femoral head is the part of the femur that fits into the
acetabulum of the pelvis.

27. T1-weighted, axial view. Image 1.
1, Rectus abdominis m.
2, external iliac vein
3, external iliac artery
4, right ovary
5, uterus
6, left ovary
7,ilium
8, rectum
9, sacrum

28. MRI of the female pelvis: T1-weighted,
axial view. Image
1, Rectus abdominis m
2, external iliac vein
3, external iliac artery
4, obturator internus m.
5, right ovary
6, endometrium
7, junctional zone
8, myometrium
9, left ovary
10, rectum

29. MRI of the female pelvis: T1-weighted,
axial view. Image
1, Rectus abdominis m.
2, external iliac vein
3, external iliac artery
4, obturator internus m.
5, head of the femur
6, endocervical canal
7, rectum
8, ischiorectal fossa
9, gluteus maximus
10, uterus

30. MRI of the female pelvis: T1-weighted,
axial view. Image
1, Rectus abdominis m.
2, femoral vein
3, femoral artery
4, pectineus muscle
5, obturator internus m.
6,bladder
7, vagina
8, anal canal
9, head of the femur
10, ischiorectal fossa
11, gluteus maximus m.

31. MRI of the female pelvis: T1-weighted, coronal view.
1, Rectus abdominis m.
2, Bladder
3, Pubis
4, fundus uterus
5, corpus uterus
6, endocervical canal
7,rectum
8, Sacrum

32. MRI of the female pelvis: T1-weighted,
coronal view.
1, Rectus abdominis m.
2, Pubis
3, Bladder
4, urethra
5, uterus
6, endometrium
7, vagina
8, rectum
9,sacrum

33. MRI anatomy of the cervix is best delineated on T2W image [Figure 1] as it outlines the four major zones of cervix.
From center to periphery, these are high signal intensity endocervical canal, intermediate signal intensity plicae palmatae,
low signal intensity fibrous stroma, and intermediate signal intensity outer smooth muscle

36. Stage II is considered when the tumor extends beyond the cervix. Involvement of the upper two-third of the
vagina is seen as segmental loss of the normally seen T2-hypointense vaginal wall and is staged as IIA [Figure 4].

37. In stage IIB, the tumor disrupts the normally seen hypointense peripheral stroma on T2W images and extends in the
parametrium [Figure 5]

38. Stage III is defined as tumor
extension to the lower third of the
vagina or lateral pelvic wall with
associated hydronephrosis.
Involvement of lower third of the
vagina without extension to pelvic
wall is IIIA [Figure 6].

39. Stage IIIB is considered when the tumor is less than 3 mm from the side wall, causes hydroureter, infiltrates the obturator
internus, pyriformis, and levator ani muscles, encases the iliac vessels, and destroys the pelvic bones [Figure 7)

40. Presence of bladder or rectal mucosa involvement or distant metastasis upgrades the tumor to stage IV.
In stage IVA, bladder and rectal invasion is suggested by the presence of focal or diffuse disruption of the normally seen T2-
low signal intensity wall, irregular or nodular wall, and presence of an intraluminal mass [Figure 8].
Figure 8(A-C):
Squamous cell carcinoma in two different patients (stage IVA). Sagittal T2W image shows a large mass arising from the cervix
and involving the uterine myometrium (white arrow in A) with invasion in the rectum demonstrated as loss of T2-low signal
intensity rectal wall (black arrow in A). Also note the infiltration in posterior bladder wall (white arrow-head in A), better seen
in the second patient on T2 and post-gadolinium image (white arrow heads in B and C)

41. Bulbous edema sign, which is hyperintense thickening of the bladder mucosa on T2W images, is an indirect sign of
invasion and should be evaluated with care for associated tumor nodule [Figure 9].

42. Vulvar squamous cell carcinoma in 53-year-old woman presenting with nonhealing ulcer. Labeled structures
are uterus (ut), bladder (b), levator ani (l), pubic bone (p), urethra (u), vagina (v), anus (a), obturator internus
(o), femoral vessels (f), and rectum (r). Sagittal fast spin-echo T2 MR image shows 4-cm skin-based mildly
hyperintense mass (arrow) in left vulva. Arrowheads indicate deep margin of mass. Deep margin of mass
(arrowheads) is approximately 1 cm from underlying pubic bone, which predicts surgical margin not
sufficiently clear of tumor. A left inguinal node (thick arrow) shows features of tumor involvement, being
abnormally enlarged (2.3 cm) on MRI.

43. Vaginal squamous cell carcinoma in 56-year-old woman presenting with postmenopausal bleeding. Labeled
structures are bladder (b), urethra (u), vagina (v), and levator ani (l). Sagittal fast spin-echo T2 (A) and axial fat-
saturated gadolinium-enhanced T1 (B) MR images show mildly hyperintense infiltrating homogeneously
enhancing mass (thin arrows) extending from posterior vaginal wall into rectum. On T2-weighted image, tumor
obliterates hypointense muscles of anal sphincter and anterior rectal wall and markedly hyperintense rectal
mucosa. Inguinal nodes (thick arrows, B) bilaterally are enlarged (2–5 cm) and show central hypoenhancement of
necrosis, all features indicating tumor involvement.

44. Contouring Guidelines for
Carcinoma Cervix (3DCRT/IMRT)

45. Target Volume delineation
 For definitive treatment of carcinoma cervix with conformal radiation techniques,
accurate target delineation is vitally important,
 Various guidelines for CTV delineation are published in the literature yet a consensus
definition of clinical target volume (CTV) remains variable
 Clinical judgement remains the most important aspect of determining the target
volumes

46. Contouring
Several contouring guidelines available for CTV
Taylor et al pelvic nodal delineation (CT based)
Toita et al for CTV delineation in intact cervix EBRT (CT based)
Lim et al for CTV delineation in intact cervix IMRT (MRI based)
Small et al for CTV delineation in post operative IMRT (CT based)
PGI literature review & guidelines for delineation of CTV for intact carcinoma cervix (CT based)
Guidelines for organ at risk
Pelvic Normal Tissue Contouring Guidelines for Radiation Therapy: A Radiation Therapy Oncology
Group Consensus Panel Atlas (CT based)

47.  The aim of the article was to review the guidelines for CTV delineation published in the literature and to
present the guidelines practiced at their institute
 6 articles : 2 articles from Taylor et al and Toita et al and 1 from Small et al., Lim et al., were reviewed
 The CTV in cervical cancer consists of the CTV nodal and CTV primary.
 CTV nodal consists of common iliac, external iliac, internal iliac, pre-sacral and obturator group of
lymph nodes
 CTV primary consists of the gross tumor volume, uterine cervix, uterine corpus, parametrium, upper
third of vagina and uterosacral ligaments.

 This was the first report to provide the complete set of guidelines for delineating both the CTV
primary and CTV nodal in combination for intact cervix

48. CTV nodal (CTV 1)
• CTV N includes involved nodes and relevant draining nodal groups (common iliac, external iliac, internal
iliac, obturator and pre sacral lymph nodes).
• Pelvic LN CTV is contoured in accordance with the latest Taylor’s guidelines with some modifications
• VESSELS: Start contouring iliac vessels from aortic bifurcation down till the appearance of femoral head.
• Uniformly, pelvic blood vessels are given a margin of 7mm. The upper border is maintained at aortic
bifurcation.
• The contour is extended around common iliac vessels posteriorly and laterally so as to include connective
tissue between iliopsoas muscles and lateral surface of vertebral body.
• All visible nodes (contoured as GTV node) are given a margin of 10mm to create CTV node.
• Muscle and bone are excluded from CTV N.

49. Common iliac nodes
The contour is extended around common iliac vessels posteriorly and laterally so as to include connective
tissue between iliopsoas muscles and lateral surface of vertebral body.

50. External iliac :7 mm margin around vessels.
 Taylor recommends contouring
external iliac nodes around external
iliac vessels until they pass through
inguinal ligament. And further
recommend extending the external
iliac contours antero-laterally along
the iliopsoas by 10 mm (a total of
17mm from the vessel) for covering
lateral external iliac group of LNs.
 Toita however exactly defines the
caudal margin of external iliac
region at the level of superior
border of femoral head, as beyond
this, external iliac vessels
pass through inguinal ligament and
continue as femoral vessels.
 Following these guidelines, large area of femoral head and neck irradiation can be avoided

51. • Both Toita and Small et al.
also do not follow this
anterolateral extension.
•
Also, out of the three groups of
LNs, the medial groups of
nodes are the one which are
considered to be the main
channel of drainage, collecting
lymph from uterine cervix and
upper vagina.
• Hence current guidelines ; do
not follow and recommend
such anterolateral extension to
external iliac region.

52.  The caudal margin of internal iliac vessels
is defined at ischial spine
 The posterior margin of internal iliac
lymph node region is defined at wing of
sacrum or anterior edge of piriformis
muscle.
 The lateral margin of internal iliac lymph
node region is defined by iliac bone,
psoas muscle or medial edge of Iliacus
muscle in cranial slices and obturator
internus muscle or piriformis muscle in
caudal slices
 Extend lateral borders to pelvic side wall
Internal iliac: 7 mm margin around vessels.

53. • To cover obturator nodes, a strip 17 mm wide is created medial to the pelvic sidewall, by joining the contour
of external iliac vessels with internal iliac vessels. Contouring of obturator nodes with 17 mm brush is
continued lower down along pelvic side wall, till superior part of obturator foramen
• From anatomical knowledge of the course of obturator vessels within the pelvis,[36] caudal border of
obturator nodes is defined at upper level of obturator foramen, since obturator artery leaves and
obturator vein enters pelvis at this level. Toita defines the caudal extent of obturator lymph node till
superior border of obturator foramen
Obturator Nodes

54. PRESACRAL NODES
• Pre-sacral region is covered by connecting the volumes on each side of
pelvis with a 10-mm strip over the anterior sacrum starting from aortic
bifurcation till S2-S3 junction.
• Sacral foramina are not included in CTV N

56. • The caudal margin of internal iliac nodes is at the level of Ischial
spine.
• The caudal margin of external iliac nodes is till the appearance of
femoral head.
• The caudal extent of obturator lymph node is till superior border of
obturator foramen

58. • All guidelines recommended excluding bones and muscles
from CTV 1.
• However, bowel was not routinely excluded by any of the guideline except
the guideline by Small et al.[13]
• This is because the later guidelines are for post operative cases of
carcinoma cervix and endometrium, where bowel loops fall
into pelvis after surgery.
• So they excluded bowel loops from CTV 1 to decrease normal tissue
toxicity.
• All other guidelines also do not exclude bladder and bowel from the nodal
contour, due to the daily changes in their shape and position.

59. CTV primary (CTV 2)
• CTV Primary (CTV-P) includes GTV Primary, Uterine Cervix, Uterine Corpus,
Parametrium, Vagina and Ovaries
• UTERUS: The uterine corpus, entire cervix and the vagina are contoured along
with the gross disease (GTV primary) as a single structure uterus (CTV 2)

60. Components of CTV
The group consensus was that
entire uterus should be
included in the CTV because:
• Uterus & cervix are
embryologically one unit with
interconnected lymphatics and
no clear separating fascial
plane
• Second, determination of
myometrial invasion can be
difficult
• uterine recurrences have been
reported (2%), but exact
location of these
recurrences(fundal vs. corpus)
have not been stated

62. • VAGINA: paravaginal tissue is included along with the vaginal wall. A vaginal
marker is placed at the lower extent of vaginal disease while taking CT and as
per RTOG guidelines:
• Minimal or no vaginal wall involvement: The contouring is stopped few slices
above the lower border of obturator foramen, so that when 1.5 cm ITV
(internal target volume) margin is given over the uterus, the lower border does
not extend beyond the lower border of obturator foramen.
• Upper vaginal involvement: Upper two-thirds
• Extensive vaginal involvement: Entire vagina
CTV primary (CTV 2)

63. PARAMETRIUM (CTV 3)
To delineate the parametrium , connective tissue extending from the cervix to the pelvic wall are included, along
with the visible linear structures that run laterally (e.g. vessels, nerves and fibrous structures)
• Cranial border : defined at the level where the true pelvis begins. Contours should stop once loops of bowel
are seen next to the uterus (Lim/Toita etal.)
• Anteriorly: contouring is done up to the level of posterior border of bladder in the central region, while, in
periphery it extends till the anterior end of lateral pelvic bony wall.
• Posteriorly: parametrium is contoured only till the anterior part (semi-circular)of mesorectal fascia. In case of
significant parametrial invasion(IIIB)/uterosacral ligament involvement, include entire mesorectum.(Lim et
al.(RTOG)/PGI Guidelines).
• Laterally, the parametrium is contoured till the lateral pelvic wall, upto the medial edge of internal obturator
muscle.
• Caudal border of parametrium is taken at the pelvic floor

64. 2 f shows parametrial contouring for cervix cancer stage II B
Cranial border : defined at the level where the true
pelvis begins. Contours should stop once loops of bowel
are seen next to the uterus
Anteriorly: contouring is done up to the level of posterior
border of bladder in the central region, while, in periphery it
extends till the anterior end of lateral pelvic bony wall
Posteriorly: parametrium is contoured only till the
anterior part (semi-circular)of mesorectal fascia

65. In case of significant parametrial invasion(IIIB)/uterosacral ligament involvement,
include entire mesorectum 2 g shows parametrial contouring for bulky stage III B,

66. Laterally, the parametrium is contoured till the lateral pelvic wall, upto the medial edge
of internal obturator muscle.
Caudal border of parametrium is taken at the pelvic floor

67. The CTV primary finally includes the uterus (CTV 2) and the parametrium (CTV 3).
Ovaries visible on CT are included within the CTV primary

68. Total CTV: CTV N(CTV1) and the CTV primary (CTV2 & CTV 3) are combined and named as total
CTV
PTV Toatal: 10 mm over total CTV to account for set up errors
ITV Margin: The uterine motion
is accounted for by giving an ITV
margin on the uterus…An
asymmetrical margin with ITV
expansion of 15 mm antero-
posteriorly, 15mm supero-
inferiorly and 7 mm laterally, is
taken from the uterus (CTV 2)
Purple: uterus
Blue:ITV
Green:CTV Total
Yellow:PTV total

69. • Final PTV (red): The ITV
margin given over CTV 2 for
uterine motion is added to
the total PTV and this is taken
as the total target volume
(final PTV) to be treated
• Purple: uterus
• Blue:ITV
• Green:CTV Total
• Yellow:PTV total
• Red: PTV Final

71. Normal Tissue Delineation (RTOG)
• Bowel: The small and large bowel can be contoured together as a Bowel-Bag.
• Inferiorly, the bowel bag should begin with the first small or large bowel loop or
above the ano-rectum, whichever is most inferior.
• The contours should end 1 cm. above the PTV .
• Ano-Rectum: Ano-Rectum should be contoured from the level of the anus to the
sigmoid flexure. It should extend from the anal verge (marked by a radiopaque marker
at simulation) to superiorly where it loses its round shape in the axial plane and
connects anteriorly with the sigmoid.
• Bladder: Contoured inferiorly from its base, and superiorly to the dome.
• Femoral Heads:The ball of the femur, trochanters, and proximal shaft to the level of
the bottom of ischial tuberosities
Gay HA, Barthold HJ, O′Meara E, Bosch WR, El Naqa I, Al-Lozi R, et al. Pelvic normal tissue contouring
guidelines for radiation therapy: A Radiation Therapy Oncology Group consensus panel atlas. Int J Radiat Oncol
Biol Phys 2012;83:e353-62.