Imaging in the guidance of BT cervical cancer

Workshop on GYN IGABT

Alina Sturdza Umesh Mahanshety

Nicole Nesvacil Maximilian Schmid

Outline

• MR delineation • CT delineation • US use in IGBT for cervical cancer • Modalities for improving target and OAR

delineation • Tips for contouring and treatment planning

in the absence of MRI for each BT application

Image guided adaptive brachytherapy (IGABT)

• Individualized: Personalized medicine

• It is adapted to the tumour size at BT, after concurrent EBRT

• Allows dose escalation while sparing the organs at risk

This house believes in MRI at

each application

MRI is the gold standard imaging modality for LACC

Tumor / Target at different points in time • Signs for judgement of tumor at time of

diagnosis • Signs for judgement of tumor / target at time

of brachytherapy (signs of regression and persistance)

Tumor Regression

Workshop on GYN IGBT CT and MR Imaging

Signs for judgement of tumor at time of diagnosis (GTVD)

vaginal invasion

invasion into the parametria

corpus invasion

High signal intensity tumor mass

necrosis GTVD

Signs for judgement of tumor/target at time of brachytherapy (regression - persistance)

IJROBP 2006

Fluid surrounding the cervical canal

Low signal intensity Cervical stroma

measurable tumor mass grey zones in the parametria

HR-CTV

61,0

7,99,010,516,3

0

10

20

30

40

50

60

70

prior to therapy 1. brachytherapy 2. brachytherapy 3. brachytherapy 4. brachytherapy

Abs

olut

e V

ol (c

m³)

Strahlenther Onkol 2009, 5

Quantitative tumor regression EBRT: tumor regression 75% Brachytherapy: tumor regression 10%

EBRT

BT

easy to predict

Workshop on GYN IGBT CT and MR Imaging

Comparison between imaging modalities EXAMPLE

Workshop on GYN IGBT CT and MR Imaging

Comparison between imaging modalities EXAMPLE

Workshop on GYN IGBT CT and MR Imaging

Comparison between imaging modalities EXAMPLE

Workshop on GYN IGBT CT and MR Imaging

Comparison between imaging modalities EXAMPLE

Workshop on GYN IGBT CT and MR Imaging

Comparison between imaging modalities EXAMPLE

Workshop on GYN IGBT CT and MR Imaging

Comparison between imaging modalities EXAMPLE

Workshop on GYN IGBT CT and MR Imaging

Comparison between imaging modalities EXAMPLE

Workshop on GYN IGBT CT and MR Imaging

Comparison between imaging modalities EXAMPLE

axial sagittal coronal

Grey zone Gross tumour

Cervix

Target / Patho-anatomical structures / GTV, HR-CTV contouring on MRI

residual tissue =grey zones

Tumour mass

Workshop on GYN IGBT CT and MR Imaging

HR-CTV

Rectum

Bladder

CTMR

Viswanathan et al. IJROBP 2007

parametrial space

Dimopoulos et al. IJROBP 2006

patho-anatomical structures CT/MRI

parametrial space

nodal structures? Soft tissue?

Workshop on GYN IGBT CT and MR Imaging

Organs at Risk – MRI High resolution multiplanar capability

Workshop on GYN IGBT CT and MR Imaging

HR-CTV

Rectum

Bladder

CTMR

Viswanathan et al. IJROBP 2007

NEEDLES

Applicator MRI /CT

TANDEM

Workshop on GYN IGBT CT and MR Imaging

excellent depiction poor quality

improvement for needles / loss of soft tissue depiction quality

proton weighted

T2 - weighted T2 - weighted

Applicator MRI

Workshop on GYN IGBT CT and MR Imaging

Workshop on GYN IGBT CT and MR Imaging

uterine border and pre-vesical space not visible

uterine border and pre-vesical space visible

Multiplanar Imaging CT / only with reconstruction (improvement with specific protocols and modern scanners)

Workshop on GYN IGBT CT and MR Imaging

Lateral uterine/tumour border not visible Lateral uterine/tumour border visible

Multiplanar Imaging CT / only with reconstruction (improvement with specific protocols and modern scanners)

B

FR

B

RS

FF

GP

RB

S

at diagnosis without vaginal

marking

at diagnosis with vaginal

marking at brachytherapy with specific protocol

IJROBP 2006

Improvement with specific protocol

Workshop on GYN IGBT CT and MR Imaging

PLANE COVERAGE-BORDERS

T2 axial discus L5 inferior border of symphysis pubis

T2 sagittal pelvic wall (obturator muscle) pelvic wall (obturator muscle) T2 frontal or frontal oblique

entire uterus - cervix - vagina - tumor

Axial Sagittal Frontal

Improvement with specific protocol

Workshop on GYN IGBT CT and MR Imaging

Slice orientation parallel/orthogonal to applicator axis

Paracoronal orientation

Paratransverse orientation

Parasagittal orientation

GEC-ESTRO HANDBOOK OF BRACHYTHERAPY

This house believes in MRI at

each application, But also in our good old

finger

/ / dd/mm/yy

Signature

w = __ _ cm h = __ _ cm t = __ _ cm

Vagina Involvement = _ _ cm

w

Infiltrative Exophytic

Cervix

Vagina

Parametria

Rectum or

Bladder

Clinical Drawing Patient: At Diagnosis

w Infiltrative Exophytic

Cervix

Vagina

Parametria

Rectum or

Bladder

Tumour size:

Width: 10 cm

Thickness: - cm

Height: - cm

Vaginal inv.: 5 cm

Clinical drawings at diagnosis

MRI findings

Before BT

Diagnosis