2. BRACHYTHERAPY
Type of radiation treatment
Consists of placing sealed radioactive
sources very close to or in contact
with the target tissue.
3. CLINICAL ADVANTAGES
High biological efficacy
Rapid dose fall-off
High tolerance
Tolerable acute intense reaction
Decreased risk of tumor population
High control rate
Minimal radiation morbidity
Day care procedure
4. LIMITATIONS & DISADVANTAGES
Difficult for inaccessible regions
Limited for small tumors (T1_T2)
Invasive procedures, require GA
Higher dose inhomogeneity
Greater conformation –small errors in
placement of sources lead to extreme
changes from the intended dose distribution
Radioactive hazards (not now)
Costly
5. SELECTION CRITERIA
Easily accessible lesions
Early stage diseases (Ideal implant ≤ 5 cm)
Well localized tumor to organ of origin
No nodal or distant metastases (radical
intent)
No local infections or inflammation
Favorable histology- mod. diff. i.e. SCC
Well controlled DM / HTN
Proliferative/exophtic lesions preferred
(better outcome)
6. INDICATIONS
SOLE MODALITY
Skin malignanciesBCC, SCC
Head & neck cancers
Ca cx
Ca prostate
BOOST( AFTER
EXT.RT±CCT)
Head & neck cancers
Ca Breast
Esophagus
Anal canal
7. INDICATIONS...
PERIOPERTIVE
STS
Ca Breast
POSTOP
Ca Endometrium
Ca cx
Ca Breast
PALLIATIVE
Bronchogenic Ca
Biliary duct
malignancy
Ca Esophagus
Recurrent tumors
BENIGN
Keloids / Pterygium
OTHERS
Endovascular/Rad.
stent
9. DOSE RATE(ICRU 38)
LOW DOSE RATE (LDR)
0.4-2 Gy/hr (clinical practice range 0.4 to 1 Gy per
hour)
MEDIUM DOSE RATE (MDR)
2-12 Gy/hr
HIGH DOSE RATE (HDR)
> 12 Gy/hr
ULTRA LOW DOSE RATE
0.01-0.3 Gy/hr
10. ADVANTAGES
LDR
HDR
Predictable clinical effects
Superior radiobiological
SHORT TREATMENT TIME
role
Less morbidity, control is
best
Well practised since long
Minimum intersession
variability in dose
distribution
Geometry well maintained
Better patient compliance /
comfort
Day care procedure
DOSE OPTIMIZATION
NO RADIATION HAZARDS
SMALL APPLICATOR
Less tissue trauma
Better packing
11. AFTER LOADING TECHNIQUE
MANUAL
Avoids radiation
protection issue of
preloading
Better applicator
placement
Verification prior to
source placement
More radiation hazard
Advantages of
preloading
REMOTE
CONTROLLED
No radiation hazard
Accurate placement
Geometry maintained
Better dose distribution
Highly precise
Short Treatment time
Day care procedure
Mainly used for HDR
14. INTERSTITIAL BRACHYTHERAPY
Sealed Radioactive sources directly
implanted into the tumor in a geometric
fashion
ADVANTAGES
Higher local dose in shorter time
Rapid dose fall
Better tumor control
Lesser radiation morbidities
Superior cosmetics
Functional preservation of organs
15. INTERSTITIAL BRACHYTHERAPY…
DISADVANTAGES
Invasive procedure
Costly
INTENTION OF TREATMENT
RADICAL INTENTION
As radical brachytherapy alone (smaller lesions)
Local boost in combination with EBRT (larger lesion)
16. SELECTION CRITERIA
Easily accessible lesions, at least from one
side
Early stage disease
T 1-T2 and sometimes early T3
Ideally total size of implant ≤ 5 cm
Well controlled DM /HTN
No local infection
17. CLINICAL APPLICATIONS
Head & neck tumors
Early stage oropharyngeal cancers
Ca breast- Boost /PBI
Ca prostate
Soft tissue sarcoma
Gynecologic malignancies
Ca anal canal and rectum
Ca lung and pancreas
18. TYPES OF INTERSTITIAL
IMPLANTS
TEMPORARY
PERMANENT
ACCORDING TO SIZE/LOCATION/PROXIMITY OF TUMOR TO NORMAL STRUCTURES
Radioactive sources
removed after desirable
dose has been delivered
Rigid stainless steel
needles/flexible Teflon /
nylon guides/plastic
tubes
Preloaded/After loaded
Preloaded – rigid needle
eg. Ra226 ,Cs137
After loaded – Manual/
Remote
Advantages
Flexibility of implant
design
Reduction of radiation
exposure levels resulting in
more accurate placement
of needles and guides
19. PERMANENT IMPLANTS
ADVANTAGES
Less accessible sites
ultra low dose rate/Max
biological effectiveness
Better tissue heal
Better effect in slow and
radio resistant tumors
Improved mobility
DISADVANTAGES
Environmental issue
Dosimetric uncertainties/
Later part of Treatment
becomes less effective
Source displacement
Large tumor /Difficult
procedure and geometry
Radio biologically less
effective for rapidly
proliferating tumors
20. CLINICAL APPLICATIONS
Oral Cavity:
LIP:
Indications: T1-2N0 Lesions (monotherapy- 0.5to5 cm or
boost therapy->5 cm)
T.V.: All visible & palpable tumour with 5-10 mm margin
Dose: 50-70Gy in 5-7 days LDR
Technique:
Rigid after loading needles maintained in place by
Template
Classical plastic tubes
Spacers to decrease dose to gingiva, teeth & other lip
21. CLINICAL APPLICATIONS…
Buccal Mucosa:
Indications:
Brachytherapy alone indicated for small (<4cm), welldefined lesions in anterior 2/3rd
As boost after EBRT for larger lesions
T.V.: GTV +0.5 to 1 cm margins
Dose: Alone 65-70 Gy
Boost 25-30 Gy
Technique: Guide Gutter Technique: Lesion < 2cm
Plastic tube technique: For other lesions
23. CLINICAL APPLICATIONS…
Floor of Mouth:
Indications: T1-2N0 lesions, ≥ 5 mm away from
mandible
Dose: monotherapy-65Gy;boost-20 to 30 Gy
Complication: bone necrosis is most common, up
to 30%
Oropharynx:
Indications: Ca BOT, soft palate, tonsillar fossa &
vallecula usually as boost after EBRT
Lesions < 5 cm (after EBRT)
T.V.: GTV + 10 mm margin
Dose: Tonsillar fossa-25-30 Gy; BOT 30-35 Gy
Technique: Classical Plastic Loop technique
24. CLINICAL APPLICATIONS…
Nasopharynx:
Ind- T1 AND T2 lesions
Dose: LDR -as a sole treatment 60Gy; as a boost 12 to 20 Gy.
HDR- 18 Gy in 6 fr
Opthalmic brachytherapy(I-125,Ru-106,Sr90)
Ind- malignant tumors of the conjuctiva, pterygium,wet macular
degeneration,neovascularization
Sr 90 dose rate-100Gy/hr,, I-125 dose rate 0.5 to 1 Gy/hr
Pterygium – Sr 90 dose varying from 20 to 60 Gy in 1 to 6 fr.
25. CLINICAL APPLICATIONS…
Breast
Indications: Boost after BCS & EBRT
Postoperative interstitial irradiation alone of
the primary tumor site after BCS in selected
low risk T1 and small T2N0 (PBI)
As sole modality
As Boost to EBRT
Patient choice: cannot come for
5-6 wks treatment :
Close, positive or unknown
margins
Distance
Lack of time
Elderly, frail, poor health patient EIC
Large breasts, unacceptable
toxicity with EBRT
Younger patients
Deep tumour in large breast
Irregularly thick target vol.
Chest wall recurrences
26. CLINICAL APPLICATIONS…
T.V.: Primary Tumor site + 2-3 cm margin
Dose: As Boost: 10-20 Gy LDR
AS PBI: 45-50 Gy in 4-5 days LDR (30-70
cGy/hour)
34 Gy/10fr, 2fr per day HDR
Technique:
Localization of PTV: Surgical clips (at least 6)
USG, CT or MRI localization, Intra op USG
During primary surgery
Guide needle technique or
Plastic tube technique using Template
Double plane implant
Skin to source distance: Minimum 5 mm
27. MAMMOSITE
Used for Accelerated Partial Breast Irradiation(APBI)
Fluid filled balloon placed during surgery
Prescription
Reference Point at 1 cm
340cGy per fraction
2 fractions per day
6 hour separation
10 fractions total
Weekend break is allowed
28. Ideal patients for APBI(ASTRO)
Tumor Size < 2 cm
Absence of nodal involvement(N0)
Absence of Metastatic Status(M0)
Age > 60 yr
Negative margins
Invasive ductal histology in the absence of
DCIS
Estrogen receptor positive
29. HDR Brachytherapy with Savi
The Savi applicator is a new single insertion
multicatheter device used for partial breast
radiation.
It has a single central catheter and multiple
peripheral catheters.
This allows the radiation dose to be tailored to
the shape of the lumpectomy cavity.
30. Contura- multi lumen baloon
Consists of a central lumen and 4 outer lumen
offering a total of 40 dwell positions
Encased in a polyurethane balloon which
maintains symmetry and reduces potential
for balloon ruputre.
31. NEW ELLIPTICAL BALOON(2004)
Provides excellent conformance
Ellipsoidal implant parellel to the chest wall
provides appropriate symmentry
32. AXXENT:NEWER DEVICE
Uses a miniaturized x-ray source to deliver low energy x-rays within
a needle or catheter.
Use of this device for APBI
No need for heavy room shielding
Stay in room with patient during treatment
No radioactive materials license needed
No handling, storing, security concerns
One source per patient
Must calibrate source before each treatment
33. CLINICAL APPLICATIONS…
Prostate:
Indications
Brachytherapy as monotherapy:
Stage T1-2a /Gleason score 2-6 / PSA ≤ 10 ng/ml
As boost after EBRT
Stage T2b, T2c /Gleason score 7-10 /PSA > 10 ng/ml
Patient factors :
Life expectancy > 5 yrs
IPSS<15
Prostate volume<60cm2
No defect if previous TURP
Minimal pubic arch interfence
T.V.: Whole prostate within capsule + 2-3 mm
margin
Methods: Permanent Implant (I125 or Pd103) or
Temporary Implant (Ir192)
34. CLINICAL APPLICATIONS…
Technique for Permanent implant
Retropubic approach with I125 seeds- Disappointing results
Modern technique: Transperineal Approach
TRUS guided
Two step approach
Volume study of prostate
pubic arch interfence assessment
Computer planning
Coverage check -USG & Flouroscopy
Bladder irrigation /Cystoscopy can be performed
Post-implant image based dosimetry
35. CLINICAL APPLICATIONS
Dose:
I125: 145 Gy as sole RT;100-110 Gy as boost to 40-50 Gy
EBRT
Pd103: 125 Gy as sole RT;90-100 Gy as boost to 40-50 Gy
EBRT
Cs 131 :115 GY as sole rt;85-95 Gy as boost to 40-50 Gy
EBRT
Temporary Implants with Ir192 (LDR or
HDR):
Procedure same as above; lesser no. of plastic
catheters required (8-15)
Dose:
LDR 30-35 Gy seeds left for 3 days(Boost to 45 Gy
EBRT)
HDR 20-25 Gy, 4-6 Gy/#(Boost to 45 Gy EBRT)
36. CLINICAL APPLICATIONS
Soft tissue Sarcomas (using Ir192 or I125)
Indications:
As sole postop RT:
completely resected intermediate or high grade tumours
of extremity or superficial trunk with -ve margins
As boost to postop EBRT:
Intermediate or high grade sarcoma with +/- margins
Postop pts with small lesions & +ve/uncertain margins
Deep lesions
Low grade sarcomas
T.V.: GTV + 2-5 cm margin
GTV based on preop MRI & clinical findings
Dose: LDR (Ir seeds or wires) as sole treatment
45-50 Gy in 4-6 days
As boost to 45-50 Gy EBRT: 15-25 Gy in 2-3 days
HDR: as sole treatment 40 t0 50 Gy in 12 to 15 fr/ as boost
to 45-50 Gy EBRT:18-25 Gy in 4-8 fr
37. CLINICAL APPLICATIONS…
Technique:
Usually performed at time of surgery
Basic or sealed end temporary implant technique
To delay the start of brachytherapy for about 4 to 7
days after surgery
limit the allowable skin dose the 40 Gy isodoseline
to <25cm2 and the 25 Gy isodose line <100 cm2
38. CLINICAL APPLICATIONS…
Brain: Permanent or temporary (using I125 or Ir192
seeds/wires )
Indications:
As boost to EBRT or recurrence
Anaplastic astrocytoma or GBM, unifocal, well
cicumscribed, peripheral lesions & < 5 cm in diameter
T.V.: Contrast enhancing area on MRI +/- 5mm
margin
Dose: LDR 50-60 Gy, 0.4-0.5 Gy/hr
39. Gliasite
Used to treat brain tumors
Balloon filled with I-125
containing solution
Example: used to treat
glioblastoma multiformae to
50 Gy followed by EBRT
boost
40. CLINICAL APPLICATIONS…
Ca Anorectum
Indications: As boost to EBRT/ChemoRT
If T.V. does not exceeds 1/2 circumference, 5 mm thick, 5
cm long i.e. T1-2 & small T3 lesions
T1N0 adenocarcinoma of rectum 3-10 cm above anus
T.V.: Visible palpable tumor+5 mm
Dose: LDR 15-20 Gy at 0.3-0.6 Gy/hr
Technique: Guide needle technique with
plastic perineal template
41. CLINICAL APPLICATIONS…
Gynecological Tumors (Ir192 LDR or HDR)
Indications:
Ca Cervix
Ca Endometrium
Postop local recurrence
Ca Vagina & Vulva
Radical BT in early lesions (T1-2N0)
Boost after EBRT in large lesions (T2-3N1)
Technique:
Guide-gutter technique
Blind plastic tube implant
(transperineal technique)
Plastic or guide needles
42. CLINICAL APPLICATION – CA
ABS Recommendations
CX
Bulky primary disease
Prior hysterectomy-inability to place tandem
Post hysterectomy
vault rec/cervical stump presentation
Extesive parametrial involvement
Distorted anatomy
Narrow vagina & fornices
Extensive / Distal vaginal wall involvement
Re-irradiation after recurrences
45. CLINICAL APPLICATIONS…
Ca Lung: Permanent perioperative BT, I125 seeds
Persistent or recurrent ds after EBRT or residual ds after
surgery
Ca Pancreas: Permanent perioperative BT, I125 seeds
Locally advanced unresectable ds
Ca Penis: scc predominant histology,
Indications – T1,T2 and T3(<4cm)that do not involve the
shaft of penis.
Based on paris system using templates(12 &18mm)
Dose ;60 Gy at a dose rate of 0.5 to0.65Gy/hr
Ca urethra: as sole treatment is 60 to 70 Gy in 3 to 5 days;
as a boost 20 to 25 Gy.
46. INTRACAVITARY APPLICATION
Radioactive sources are placed in a existing
cavity usually inside a predefined applicator
with special geometry
Uses:
Cervix
Endometrium
Vagina
Maxilla
Nasopharynx
47. DOSE SCHEDULE
LDR (<200cgy/hr)
35-40 Gy at point A
MDR (200-1200cgy/hr)
35 Gy LDR EQUIVALENT at point A
HDR(>1200cgy/hr)
9 Gy in 2 fr
6.8Gy in 3 fr at point A
48. EXTERNAL RT WITH
BRACHYTHERAPYfollow external irradiation
Brachytherapy can
SIMULTANEOUS
Stage I - II with very minimal parametriun
involvement
HDR -5 sessions (9gy /fr, 1week apart)
40 Gy by EBRT simultaneously
SANDWICH
Stage I-II
40 Gy LDR eq.—› EBRT 40 Gy
In both above cases a MIDLINE SHIELD is
used
49. POST OP/ VAULT
Vault RT
BRACHYTHERAPY
No residual disease
8500 cGy at 5mm from the surface of the
vault
2 sessions 1 week apart
Residual disease
CTV of 2 cm given to gross tumor and the
prescription of 8500cgy encompassing the
whole CTV is made
2 sessions 1 week apart
Mostly after EBRT
50. POST OP BRACHYTHERAPY
CONTRAINDICATIONS
Vaginal wall involvement ( middle- lower 13)
Heavy parametrium infiltration
VVF or VRF
Inadequate space
Medical contraindications
Metastatic disease
Supplementary radiation 2000 cGy 10fr
51. SURFACE MOULDS
Radiation is delivered by arranging RA
sources over the surface of tumor
Types
Planar
Circular
Square
Rectangular
Line source
Cylinder
52. INDICATIONS
Superficial /Accessible tumors
keloid : Sr90 , 20 gy in 4 fr after surgery.
Skin ca – HAM applicator, Freiburg flab are
surface template applicators, dose – 35 to 50
Gy in 5 to 10 fr.
Post mastectomy recurrence – LDR- 65 Gy in
2 to 3 fr,monthly intervals.
Oral tumor
hard palate ,alveolus,oral cavity,lip
as a sole modality 60 GY,as boost to 45 to 50 GY-
15 TO 30 Gy.
Penile carcinoma
53. INTRALUMINAL BRACHYTHERAPY
Radioactive source is passed through a tube and
passed into a hollow lumen
Sites
Esophagus : TV-tumor+distal and proximal margin of
2 to 3 cm
Dose: palliative-16 GY IN 2 FR or 18 GY IN 3 FR.
as boost EBRT 50 Gy-HDR 10 Gy in 2 fr at 1 cm
from surface.
54. ILBT..
Bronchus : Bronchogenic carcinoma
Definitive : T1-T2tumors
HDR- sole treatment-5Gy in 5 fr or 7.5 Gy in 2 fr
prescribed to 1cm.
as boost to EBRT treatment(45 TO 60 Gy)- three 5
Gy fr or two 7.5 GY fr
Palliative :
Dyspnea,hemoptysis,post obstructive pneumonitis
Poor lung function
Previous EBRT
Dose : 7.5Gy/fr in3 weekly fr, 10Gy/fr in 2 fr, 6Gy/fr in 4
fr prescribed at 1 cm.
Boost treatment- 30 Gy in 10 to 12 fr
55. Biliary tract
Ind – unresectable tumors
Technique – endoscopic retrograde technique
BT delivered throug a transhepatic
cholangiogram
TV- tumor +1 to 2 cm proximal and distal
margin
Monotherapy- palliative dose 30 gy in 6 fr
As boost(45 Gy EBRT) – 15 TO 20 Gy in 3 to 4
fr.
56. Intra vascular
brachytherapy
Coronary artery disease caused
by occlusion of cardiac vessels
IVB used to prevent restenosis
after angioplasty
Radiation delivered either with
temporary implant or radioactive
stent
57. Intra operative Radiation
brachytherapy
Attractive for deep tumors
because the skin dose was
limiting prior to the invention
of megavoltage accelerators.
Applications include:
retroperitoneal
sarcoma, pancreatic cancer,
rectal cancer, pediatric
tumors,malignant thoracic
tumors.
dose of 10 to 20 Gy in single
fr over 10 to 30 minutes.
58. Image guided brachytherapy
Image-guided brachytherapy may provide
better dose distribution to the target tumor
and reduced dose volumes to surrounding
healthy tissues when compared with imageguided IMRT and IMPT.
The use of imaging techniques, such as
ultrasound,CT and MRI for treatment
planning, has led to improved visualization of
the tumor and surrounding organs.
59. IGBT…
Applicators used for IGBRT should be such
that the applicator does not produce an
artifact on the cross sectional imaging
technique being used. For this purpose
special CT/MRI Compatible applicators
should be used. The applicators are usually
made up of a titanium alloy Now a days
carbon fibre based brachytherapy
applicators are also available.
MR is an ideal image guidance modality
for image guided brachytherapy.
Outstanding visualization of pelvic
60. Adaptive Brachytherapy
Adaptive Brachytherapy can be defined as
temporally changing the treatment plan
delivered to a patient based on observed
anatomic changes caused by tumor shrinkage,
weight loss, or internal motion.
Plans are altered throughout the treatment
course for every course of treatment depending
on tumor volume.
Patient setup and organ motion obtained from
imaging during treatment to alter the treatment
plan.
61. ROBOTIC BRACHYTHERAPY
Improve accuracy of needle placement
and seed delivery
Improve consistency of seed implant
Improve avoidance of critical structures
Reduce radiation exposure
MAINLY USED FOR CA PROSTATE
Seed placement error is at sub millimeter
level.
62. Intensity modulated
brachytherapy
This modulation is specific for the patient and allows for high
intensity radiation treatment of tumor tissue with limited
destructive effects on surrounding normal tissue.
Intensity modulated sources based on Monte Carlo
simulations
a “modified TG43” (mTG43) dose calculation algorithm
developed specifically for IMBT dosimetry. the anisotropic
function of a IMBT source, is a function of both the position
of measurement and the intensity distribution of the source
an inverse IMBT treatment planning method based on Dose
Volume Histogram (DVH) or Dose Surface Histogram (DSH)
constraints and simulated annealing optimization algorithm.