Treatment Techniques for the Pelvis Region - Prostate
Treatment Techniques
for the Pelvis Region
- Prostate(- Cervix Ca -)
Uwe Götz, Bernd Schicker
Institute of Radiation Oncology Limburg,
Germany
Treatment Techniques for the Pelvis Region - Prostate
Textbook Techniques
Perez & Prady – Principles and Practice of Radiation Oncology
... A variety of techniques have been used, raging from parallel
anteroposterior portals with perineal appositional field to lateral
portals (box techniques) or rotational fields to supplement the dose
to the prostate.
In recent years, three-dimesional conformal radiotherapy (3-D
CRT) and intensity modulated irradiation techniques have been
used increasingly in selected centers.
My Opinion:
- Treatment Planing based on Radiograph should be history !
- CT based Treatment Planning should be standard – 3-D CRT!
Treatment Techniques for the Pelvis Region - Prostate
3-D Conformal Treatment Planning
Definition of 3-D CRT:
- CT Dataset for Treatment Planning, Spaceing 1-0.5 cm.
- Delination and Definition of the Organs at Risk (OR) and
Target Volume in each CT slice.
- Definition of the field (gantry and collimator angle and field
borders) under the Beams Eye View (BEV) of the Treatment
Planning System (TPS)
- Planning and optimisation of the Dose distribution in each
CT slice.
- Dose Distribution conformal to TV and OR; ICRU
Recomondations
Treatment Techniques for the Pelvis Region - Prostate
Target Volume
- CT Dataset with 22 CT Slices
- Spaceing 0.5 cm.
Treatment Techniques for the Pelvis Region - Prostate
Treatmen Planning – AP / PA Fields
Treatment Techniques for the Pelvis Region - Prostate
Treatmen Planning – AP / PA
Treatment Techniques for the Pelvis Region - Prostate
DVH – AP / PA Fields
Treatment Techniques for the Pelvis Region - Prostate
Treatmen Planning – Box Fields
Treatment Techniques for the Pelvis Region - Prostate
DVH – Box Fields
Treatment Techniques for the Pelvis Region - Prostate
DVH – AP / PA Fieds vs Box Fields
Treatment Techniques for the Pelvis Region - Prostate
Improvement – Box Fields
Homegneous Dose Distribution the Target Volume
Quality Index of 94
OK
High Dose to the Oragn at
Risk (Rectum)
NOT OK !!!
Treatment Techniques for the Pelvis Region - Prostate
Improvement – Box Fields
High Dose to the Organ at
Risk (Rectum)
NOT OK !!!
Solution:
Find the area at the OR
with high dose level
Find the Area at the OR
with a high dose level
Treatment Techniques for the Pelvis Region - Prostate
Modification of the AP / PA Fields
Area that should be
protected to reduce the
dose dowards the OR
Solution:
Shielding by a satelite or
Multi Leaf Collimator
Treatment Techniques for the Pelvis Region - Prostate
Field Setup of the Box Technique
180° Field / Collimator Rotation to 270°
Treatment Techniques for the Pelvis Region - Prostate
Dose Volume Histohgram
Treatment Techniques for the Pelvis Region - Prostate
DVH – Box vs Improved Box
Treatment Techniques for the Pelvis Region - Prostate
Advanced Techniques
- Crossfire Technique Clinical Case:
70-year old patient
Diagnosis: Adenocarcinoma of the prostate. PSA- Increase to 8.22 ng/ml.
Histology: Medium- to low graded differentiated adenocarcinoma of the
prostate; tumor stadium pT3a, N0, M0, G2, R1 (Gleason-Grading: 7).
Therapy: Status after radical perineal prostaticovesiculectomy. For a
better tolerance, at an aimed total dose of 76.4 Gy, the therapy starts
with the boost series applied to the tumor bed (Dose per fraction: 2.0 Gy;
total dose: 26.0 Gy). The main series provides the box of the prostate and
the loco regional lymphatic drainage area with a dose per fraction of 1.8
Gy at an total dose of 50.4 Gy.
Treatment Techniques for the Pelvis Region - Prostate
Advanced Techniques
Target Volume Definition:
The target volume of the primary series contains the primary tumor and
the lymph nodes. Normally the target volume contains the primary tumor
which means the prostate and the seminal vesicles. In the case of smaller
tumors the seminal vesicles could be excluded from the target volume. In
the cranial area the target volume begins at the bifurcation of the A. iliaca
communis in the A. Iliaca interna and externa.
Treatment Techniques for the Pelvis Region - Prostate
Advanced Techniques
Target Volume:
Treatment Techniques for the Pelvis Region - Prostate
Advanced Techniques
Patient Modell:
Room View
Target Volume (red)
Urinary Bladder (blue)
Tectum (green)
Treatment Techniques for the Pelvis Region - Prostate
Advanced Techniques
Beam Setup:
A monoisocenter technique composed by
eight fixed fields with individual absorbers
and wedges are arranged around the patient
in a nearly equidistant angle was developed.
The lateral fields only cover the whole target
volume. The fields with a diagonal beam 7
direction respectively limit to one side of the
target volume and enable in this way an
adaption to its biconcave shape.
1
2
3
8
6
4
5
Treatment Techniques for the Pelvis Region - Prostate
Advanced Techniques
Physical Treatment Planning:
The common isocenter of all fields is located in the center of the body,
in this case 6 cm in the dorsal direction of the cranial edge of the
1
symphysis.
2
3
Here the eight fields are divided into
three groups. The first two groups form
a self- contained functional unit in which
the field- and absorber borders as well
7
8
as the weighting have to be reconciled
with each other.
6
4
5
Treatment Techniques for the Pelvis Region - Prostate
Advanced Techniques
Group I - Field 1 to 3:
Dose adaption to the concave part in the direction to the urinary
bladder and the cranial divided area of the target volume.
For the beam direction of the field 2
and 3 in the beam´s eye view a gantry
position is searched in which the
tangent to the ventral tip of the target
volume coincides with the center of the
“bottom” of the target volume.
Field 2
Field 3
Treatment Techniques for the Pelvis Region - Prostate
Advanced Techniques
An individual absorber in field 2 (in field 3
Field 2
correspondingly symmetrical) protects in the
complete cranial part of the target volume
the contra lateral side of the target volume
(arrow). Caudalward both fields cover the
target volume at its complete width. Because
of the half sided absorbing in the cranial part a
symmetrical underdosage is the result, which is
compensated through a separate field (field 1). Its beam direction is at
gantry position 0° and enables with the central absorber, especially in
the bipartite area of the target volume, a maximum protection of the
healthy tissue. The caudal field boundary of field 1 geometrically
coincides with the caudal edge of the absorber of field 2 (and 3) what
can be seen in the beam’s eye view.
Treatment Techniques for the Pelvis Region - Prostate
Advanced Techniques
The caudal field boundary of field 1 geometrically coincides with the caudal edge
of the absorber of field 2 (and 3) what can
be seen in the beam’s eye view.
Treatment Techniques for the Pelvis Region - Prostate
Advanced Techniques
Group II - Field 4 to 6
Dose adaption to the concave area to the rectum and in the cranial
divided part of the target volume.
Field 5
The interplay of the field 4 to 6 is similar.
Here the absorber (arrow) is shown which
enables to adapt the course of the isodoses
to the concave shape of the target volume
in the area of the rectum. Cranialward the
field ends near the bifurcation of the target volume.
Cranialward field 4 from 180° links up to the fields 5 and 6.
Treatment Techniques for the Pelvis Region - Prostate
Advanced Techniques
Group II - Field 4 to 6
Cranialward field 4 from 180° links up to the fields 5 and 6.
Treatment Techniques for the Pelvis Region - Prostate
Advanced Techniques
2
Group III - Field 7 and 8
Relief of the normal tissue ventraland dorsalward of the target volume.
The fields 7 and 8 are a variation of
the conventional “Box”-Technique.
But they are inclined dorsalward in
that way (here 2°), that the dorsal
field boundaries coincides in the
relevant area of the rectum.
1
3
7
8
4
Treatment Techniques for the Pelvis Region - Prostate
Advanced Techniques
All fields with a diagonal beam direction are equipped with a 60° wedge
(with the tip in the lateral direction), to relieve the
area which is covered by all the fields
and is situated in the center of the
target volume (yellow area).
Field configuration
in the middle section of the target volume.
Treatment Techniques for the Pelvis Region - Prostate
Advanced Techniques
Beam Parameter:
Treatment Techniques for the Pelvis Region - Prostate
Advanced Techniques
Dose Distribition
Dose Distribution in the Digitally Reconstructed Section
100%
90%
85%
80%
70%
50%
30%
10%
Frontal section
Lateral sagittal section
Median sagittal section
Treatment Techniques for the Pelvis Region - Prostate
Advanced Techniques
Dose Distribution
Treatment Techniques for the Pelvis Region - Prostate
Advanced Techniques
Dose Distribution
Treatment Techniques for the Pelvis Region - Prostate
Advanced Techniques
Dose Distribution
Treatment Techniques for the Pelvis Region - Prostate
Advanced Techniques
Dose Distribution
Treatment Techniques for the Pelvis Region - Prostate
Advanced Techniques
Dose Volume Histogram
2nd International Symposium on Target Volume Definition - Limburg - May 30 - June 01 2002
Conformal Technique for
CERVIX CARCINOMA
Short Overview
Bernd Schicker
Uwe Götz and I. Chr. Kiricuta
ISRO-Limburg - Germany
2nd International Symposium on Target Volume Definition - Limburg - May 30 - June 01 2002
TARGET VOLUME DEFINITION
2nd International Symposium on Target Volume Definition - Limburg - May 30 - June 01 2002
LIMBURG-TECHNIQUE
2nd International Symposium on Target Volume Definition - Limburg - May 30 - June 01 2002
Field set up in the „V“-shape area of the PTV
2nd International Symposium on Target Volume Definition - Limburg - May 30 - June 01 2002
Field set up in the cranial and caudal part of the PTV
2nd International Symposium on Target Volume Definition - Limburg - May 30 - June 01 2002
How to use the marker in the „V“-shaped area
of the PTV
2nd International Symposium on Target Volume Definition - Limburg - May 30 - June 01 2002
FIELD PARAMETER
2nd International Symposium on Target Volume Definition - Limburg - May 30 - June 01 2002
How to use a MLC
2nd International Symposium on Target Volume Definition - Limburg - May 30 - June 01 2002
DOSE DISTRIBUTION
in sagittal reconstructed slices
BC
A
A
B
C
2nd International Symposium on Target Volume Definition - Limburg - May 30 - June 01 2002
DOSE DISTRIBUTION in CT-slices
2nd International Symposium on Target Volume Definition - Limburg - May 30 - June 01 2002
DOSE DISTRIBUTION in CT-slices
2nd International Symposium on Target Volume Definition - Limburg - May 30 - June 01 2002
DOSE DISTRIBUTION in CT-slices
2nd International Symposium on Target Volume Definition - Limburg - May 30 - June 01 2002
DOSE DISTRIBUTION in CT-slices
2nd International Symposium on Target Volume Definition - Limburg - May 30 - June 01 2002
DOSE VOLUME HISTOGRAM
Treatment Techniques for the Pelvis Region - Prostate
Thank You Very Much