1. In the name of
God
Brachytherapy for Malignant Gliomas
z.Mansouri
Shahid Beheshti university medical of science
2. Introduction
Primary malignant brain tumors
are among the most aggressive of
all human neoplasms.
Astrocytoma represent about 40%
of all brain tumors & 75% of
astrocytomas are anaplastic(grade
III) and GBM(grade IV).
3. Why Brachytherapy?
most patients with GBM fail
locally within close proximity to
the original tumor. Given this
pattern of failure, there has been
much interest in radiation dose
escalation in improving clinical
outcomes of this patient
population.
One way for this, is BT
5. Indications
the eligibility criteria for BT:
Unifocal
Supratentorial
Not larger than 5cm(in largest
diameter)
Without ventricular,corpus
callosum or brain stem infiltration
Good performance status (kps>60)
6. Physics of brachytherapy
Most commen source for
brachytherapy of brain is I-125.
Implants are
1.temporary high activity
or
2. permanent low activity
7. Temporary implant
1.CT or MRI for tumor localization
2. fixation of a stereotactic frame at
4 points to the patients skull under
local or general anesthesia.
3.CECT (cuts: 3-5mm) to ensure of
frame location
4.preplanning;
countoring TV(tumor+/-5mm margin)
Determination of suitable&length of catheters
8. Temporary implant
5. Neurosurgeon placing catheter
precutaneously and parallel to each
other at the calculated positions.
6.CECT for analysis of the catheter
configuration (24h after implantation)
and treatment planning.
7.loading the source with
afterloading system.
9. 8.After 6 days and delivery 50 GY
to tumor and its margin,the
cathters are dislodged.
10.
11.
12. Permanent implant
source:Low activity I-125 seeds
For patients with recurrent GBM
Can be done after debulking of the
tumor, sources are placed along the
walls of the resection cavity at 0.5-
to 1.0-cm intervals
CT scan for dosimetric calculation
Removal of the catheters can be
done without anesthesia
15. During the tumor
resection, the
balloon portion of
the GliaSite
catheter is placed
within the
resection cavity
,The other end of
the catheter
serves as the
injection port and
is fixed on top of
the skull and
concealed
underneath the
skin
23. Gliasite implant
After 3-7 days and dose
delivery (40-60GY) at 0.5 cm to
1 cm from the balloon surface At
the end of this period, the Iotrex
and saline are withdrawn and the
balloon catheter is then removed
during a brief surgical procedure.
24.
25. Thank you !
References:
1.brachy therapy,application and techniques
2.booklet of overview of brachytherapy
3.principles and practice of brachytherapy ,using
afterloading systems.
