2. BRACHYTHERAPY
ī§ Type of radiation treatment
ī§ Consists of placing sealed radioactive
sources very close to or in contact
with the target tissue.
3. CLINICAL ADVANTAGES
ī§ High biological efficacy
ī§ Rapid dose fall-off
ī§ High tolerance
ī§ Tolerable acute intense reaction
ī§ Decreased risk of tumor population
ī§ High control rate
ī§ Minimal radiation morbidity
ī§ 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 âsmall errors in
placement of sources lead to extreme
changes from the intended dose distribution
ī§ Radioactive hazards (not now)
ī§ Costly
ī§
ī§
ī§
ī§
ī§
5. SELECTION CRITERIA
ī§ Easily accessible lesions
ī§ Early stage diseases (Ideal implant ⤠5 cm)
ī§ Well localized tumor to organ of origin
ī§ No nodal or distant metastases (radical
ī§
ī§
ī§
ī§
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
ī§ SOLE MODALITY
īē Skin malignanciesBCC, SCC
īē Head & neck cancers
īē Ca cx
īē Ca prostate
ī§ BOOST( AFTER
EXT.RTÂąCCT)
īē Head & neck cancers
īē Ca Breast
īē Esophagus
īē Anal canal
7. INDICATIONS...
ī§ PERIOPERTIVE
īē STS
īē Ca Breast
ī§ POSTOP
īē Ca Endometrium
īē Ca cx
īē Ca Breast
ī§ PALLIATIVE
īē Bronchogenic Ca
īē Biliary duct
malignancy
īē Ca Esophagus
īē Recurrent tumors
ī§ BENIGN
īē Keloids / Pterygium
ī§ OTHERS
īē Endovascular/Rad.
stent
9. DOSE RATE(ICRU 38)
ī§ LOW DOSE RATE (LDR)
īē 0.4-2 Gy/hr (clinical practice range 0.4 to 1 Gy per
hour)
ī§ MEDIUM DOSE RATE (MDR)
īē 2-12 Gy/hr
ī§ HIGH DOSE RATE (HDR)
īē > 12 Gy/hr
ī§ ULTRA LOW DOSE RATE
īē 0.01-0.3 Gy/hr
10. ADVANTAGES
LDR
HDR
ī§ Predictable clinical effects
ī§ Superior radiobiological
ī§ SHORT TREATMENT TIME
role
ī§ Less morbidity, control is
best
ī§ Well practised since long
ī§ Minimum intersession
variability in dose
distribution
īē Geometry well maintained
īē Better patient compliance /
comfort
īē Day care procedure
ī§ DOSE OPTIMIZATION
ī§ NO RADIATION HAZARDS
ī§ SMALL APPLICATOR
īē Less tissue trauma
īē Better packing
11. AFTER LOADING TECHNIQUE
ī§ MANUAL
īē Avoids radiation
īē
īē
īē
īē
protection issue of
preloading
Better applicator
placement
Verification prior to
source placement
More radiation hazard
Advantages of
preloading
ī§ REMOTE
CONTROLLED
īē
īē
īē
īē
īē
īē
īē
īē
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
ī§ Sealed Radioactive sources directly
implanted into the tumor in a geometric
fashion
ī§ ADVANTAGES
īē
īē
īē
īē
īē
īē
Higher local dose in shorter time
Rapid dose fall
Better tumor control
Lesser radiation morbidities
Superior cosmetics
Functional preservation of organs
15. INTERSTITIAL BRACHYTHERAPYâĻ
ī§ DISADVANTAGES
īē Invasive procedure
īē Costly
ī§ INTENTION OF TREATMENT
īē RADICAL INTENTION
ī As radical brachytherapy alone (smaller lesions)
ī Local boost in combination with EBRT (larger lesion)
16. SELECTION CRITERIA
ī§ Easily accessible lesions, at least from one
side
ī§ Early stage disease
īē T 1-T2 and sometimes early T3
īē Ideally total size of implant ⤠5 cm
ī§ Well controlled DM /HTN
ī§ No local infection
17. CLINICAL APPLICATIONS
ī§ Head & neck tumors
īē Early stage oropharyngeal cancers
ī§ Ca breast- Boost /PBI
ī§ Ca prostate
ī§ Soft tissue sarcoma
ī§ Gynecologic malignancies
ī§ Ca anal canal and rectum
ī§ Ca lung and pancreas
18. TYPES OF INTERSTITIAL
IMPLANTS
ī§ TEMPORARY
ī§ PERMANENT
ACCORDING TO SIZE/LOCATION/PROXIMITY OF TUMOR TO NORMAL STRUCTURES
īē Radioactive sources
removed after desirable
dose has been delivered
īē Rigid stainless steel
needles/flexible Teflon /
nylon guides/plastic
tubes
īē Preloaded/After loaded
īē Preloaded â rigid needle
eg. Ra226 ,Cs137
īē After loaded â Manual/
Remote
īē Advantages
ī Flexibility of implant
design
ī Reduction of radiation
exposure levels resulting in
more accurate placement
of needles and guides
19. PERMANENT IMPLANTS
ADVANTAGES
īē Less accessible sites
īē ultra low dose rate/Max
biological effectiveness
īē Better tissue heal
īē Better effect in slow and
radio resistant tumors
īē Improved mobility
DISADVANTAGES
īē Environmental issue
īē Dosimetric uncertainties/
Later part of Treatment
becomes less effective
īē Source displacement
īē Large tumor /Difficult
procedure and geometry
īē Radio biologically less
effective for rapidly
proliferating tumors
20. CLINICAL APPLICATIONS
Oral Cavity:
ī§ LIP:
īē Indications: T1-2N0 Lesions (monotherapy- 0.5to5 cm or
boost therapy->5 cm)
T.V.: All visible & palpable tumour with 5-10 mm margin
īē Dose: 50-70Gy in 5-7 days LDR
īē Technique:
ī Rigid after loading needles maintained in place by
Template
ī Classical plastic tubes
īē Spacers to decrease dose to gingiva, teeth & other lip
21. CLINICAL APPLICATIONSâĻ
Buccal Mucosa:
īē Indications:
īē
īē
īē
īē
ī Brachytherapy alone indicated for small (<4cm), welldefined lesions in anterior 2/3rd
ī As boost after EBRT for larger lesions
T.V.: GTV +0.5 to 1 cm margins
Dose: Alone 65-70 Gy
ī Boost 25-30 Gy
Technique: Guide Gutter Technique: Lesion < 2cm
Plastic tube technique: For other lesions
23. CLINICAL APPLICATIONSâĻ
Floor of Mouth:
īē Indications: T1-2N0 lesions, âĨ 5 mm away from
mandible
īē Dose: monotherapy-65Gy;boost-20 to 30 Gy
īē Complication: bone necrosis is most common, up
to 30%
Oropharynx:
īē Indications: Ca BOT, soft palate, tonsillar fossa &
vallecula usually as boost after EBRT
ī Lesions < 5 cm (after EBRT)
īē T.V.: GTV + 10 mm margin
īē Dose: Tonsillar fossa-25-30 Gy; BOT 30-35 Gy
īē Technique: Classical Plastic Loop technique
24. CLINICAL APPLICATIONSâĻ
ī§ 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
ī§ 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 â Sr 90 dose varying from 20 to 60 Gy in 1 to 6 fr.
25. CLINICAL APPLICATIONSâĻ
Breast
īēIndications: Boost after BCS & EBRT
ī 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
ī§ Distance
ī§ 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.
ī Chest wall recurrences
26. CLINICAL APPLICATIONSâĻ
ī§ T.V.: Primary Tumor site + 2-3 cm margin
ī§ Dose: As Boost: 10-20 Gy LDR
ī AS PBI: 45-50 Gy in 4-5 days LDR (30-70
cGy/hour)
ī 34 Gy/10fr, 2fr per day HDR
ī§ Technique:
īē Localization of PTV: Surgical clips (at least 6)
ī USG, CT or MRI localization, Intra op USG
īē During primary surgery
īē Guide needle technique or
īē Plastic tube technique using Template
ī Double plane implant
ī Skin to source distance: Minimum 5 mm
27. MAMMOSITE
ī§ Used for Accelerated Partial Breast Irradiation(APBI)
ī§ 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)
ī§ Tumor Size < 2 cm
ī§ Absence of nodal involvement(N0)
ī§ Absence of Metastatic Status(M0)
ī§ Age > 60 yr
ī§ Negative margins
ī§ Invasive ductal histology in the absence of
DCIS
ī§ 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
ī§ Consists of a central lumen and 4 outer lumen
offering a total of 40 dwell positions
ī§ Encased in a polyurethane balloon which
maintains symmetry and reduces potential
for balloon ruputre.
31. NEW ELLIPTICAL BALOON(2004)
ī§ Provides excellent conformance
ī§ Ellipsoidal implant parellel to the chest wall
provides appropriate symmentry
32. AXXENT:NEWER DEVICE
ī§ Uses a miniaturized x-ray source to deliver low energy x-rays within
a needle or catheter.
ī§ Use of this device for APBI
ī§ No need for heavy room shielding
ī§
Stay in room with patient during treatment
ī§
No radioactive materials license needed
ī§
No handling, storing, security concerns
ī§
One source per patient
ī§
Must calibrate source before each treatment
33. CLINICAL APPLICATIONSâĻ
Prostate:
ī§ Indications
īē Brachytherapy as monotherapy:
ī Stage T1-2a /Gleason score 2-6 / PSA ⤠10 ng/ml
īē As boost after EBRT
ī Stage T2b, T2c /Gleason score 7-10 /PSA > 10 ng/ml
ī§ Patient factors :
īē
īē
īē
īē
īē
Life expectancy > 5 yrs
IPSS<15
Prostate volume<60cm2
No defect if previous TURP
Minimal pubic arch interfence
ī§ T.V.: Whole prostate within capsule + 2-3 mm
margin
ī§ Methods: Permanent Implant (I125 or Pd103) or
Temporary Implant (Ir192)
34. CLINICAL APPLICATIONSâĻ
Technique for Permanent implant
ī§ Retropubic approach with I125 seeds- Disappointing results
ī§ Modern technique: Transperineal Approach
īē TRUS guided
īē Two step approach
ī Volume study of prostate
ī pubic arch interfence assessment
īē Computer planning
ī§ Coverage check -USG & Flouroscopy
ī§ Bladder irrigation /Cystoscopy can be performed
ī§ Post-implant image based dosimetry
35. CLINICAL APPLICATIONS
ī§ Dose:
īē I125: 145 Gy as sole RT;100-110 Gy as boost to 40-50 Gy
EBRT
īē Pd103: 125 Gy as sole RT;90-100 Gy as boost to 40-50 Gy
EBRT
īē Cs 131 :115 GY as sole rt;85-95 Gy as boost to 40-50 Gy
EBRT
Temporary Implants with Ir192 (LDR or
HDR):
īē Procedure same as above; lesser no. of plastic
catheters required (8-15)
īē Dose:
ī LDR 30-35 Gy seeds left for 3 days(Boost to 45 Gy
EBRT)
ī HDR 20-25 Gy, 4-6 Gy/#(Boost to 45 Gy EBRT)
36. CLINICAL APPLICATIONS
Soft tissue Sarcomas (using Ir192 or I125)
ī§ Indications:
īē As sole postop RT:
ī completely resected intermediate or high grade tumours
of extremity or superficial trunk with -ve margins
īē As boost to postop EBRT:
ī Intermediate or high grade sarcoma with +/- margins
ī Postop pts with small lesions & +ve/uncertain margins
ī Deep lesions
ī Low grade sarcomas
ī§ T.V.: GTV + 2-5 cm margin
ī GTV based on preop MRI & clinical findings
ī§ Dose: LDR (Ir seeds or wires) as sole treatment
45-50 Gy in 4-6 days
ī 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 APPLICATIONSâĻ
Technique:
īē Usually performed at time of surgery
īē Basic or sealed end temporary implant technique
īē To delay the start of brachytherapy for about 4 to 7
days after surgery
īē limit the allowable skin dose the 40 Gy isodoseline
to <25cm2 and the 25 Gy isodose line <100 cm2
38. CLINICAL APPLICATIONSâĻ
Brain: Permanent or temporary (using I125 or Ir192
seeds/wires )
ī§ Indications:
īē As boost to EBRT or recurrence
īē Anaplastic astrocytoma or GBM, unifocal, well
cicumscribed, peripheral lesions & < 5 cm in diameter
ī§ T.V.: Contrast enhancing area on MRI +/- 5mm
margin
ī§ Dose: LDR 50-60 Gy, 0.4-0.5 Gy/hr
39. Gliasite
ī§ Used to treat brain tumors
ī§ Balloon filled with I-125
containing solution
ī§ Example: used to treat
glioblastoma multiformae to
50 Gy followed by EBRT
boost
40. CLINICAL APPLICATIONSâĻ
Ca Anorectum
ī§ Indications: As boost to EBRT/ChemoRT
ī If T.V. does not exceeds 1/2 circumference, 5 mm thick, 5
cm long i.e. T1-2 & small T3 lesions
ī T1N0 adenocarcinoma of rectum 3-10 cm above anus
ī§ T.V.: Visible palpable tumor+5 mm
ī§ Dose: LDR 15-20 Gy at 0.3-0.6 Gy/hr
ī§ Technique: Guide needle technique with
plastic perineal template
41. CLINICAL APPLICATIONSâĻ
Gynecological Tumors (Ir192 LDR or HDR)
ī§ Indications:
īē Ca Cervix
īē Ca Endometrium
ī Postop local recurrence
īē Ca Vagina & Vulva
ī Radical BT in early lesions (T1-2N0)
ī Boost after EBRT in large lesions (T2-3N1)
ī§ Technique:
īē Guide-gutter technique
īē Blind plastic tube implant
(transperineal technique)
īē Plastic or guide needles
42. CLINICAL APPLICATION â CA
ABS Recommendations
CX
īē Bulky primary disease
īē Prior hysterectomy-inability to place tandem
īē Post hysterectomy
īē vault rec/cervical stump presentation
īē Extesive parametrial involvement
īē Distorted anatomy
īē Narrow vagina & fornices
īē Extensive / Distal vaginal wall involvement
īē Re-irradiation after recurrences
45. CLINICAL APPLICATIONSâĻ
īē Ca Lung: Permanent perioperative BT, I125 seeds
ī Persistent or recurrent ds after EBRT or residual ds after
surgery
īē Ca Pancreas: Permanent perioperative BT, I125 seeds
ī Locally advanced unresectable ds
īē Ca Penis: scc predominant histology,
Indications â 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
īē 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
ī§ Radioactive sources are placed in a existing
cavity usually inside a predefined applicator
with special geometry
ī§ Uses:
īē Cervix
īē Endometrium
īē Vagina
īē Maxilla
īē Nasopharynx
47. DOSE SCHEDULE
ī§ LDR (<200cgy/hr)
īē 35-40 Gy at point A
ī§ MDR (200-1200cgy/hr)
īē 35 Gy LDR EQUIVALENT at point A
ī§ HDR(>1200cgy/hr)
īē 9 Gy in 2 fr
īē 6.8Gy in 3 fr at point A
48. EXTERNAL RT WITH
BRACHYTHERAPYfollow external irradiation
ī§ Brachytherapy can
īē SIMULTANEOUS
ī Stage I - II with very minimal parametriun
involvement
ī HDR -5 sessions (9gy /fr, 1week apart)
ī 40 Gy by EBRT simultaneously
īē SANDWICH
ī Stage I-II
ī 40 Gy LDR eq.ââē EBRT 40 Gy
ī§ In both above cases a MIDLINE SHIELD is
used
49. POST OP/ VAULT
ī§ Vault RT
BRACHYTHERAPY
īē No residual disease
ī 8500 cGy at 5mm from the surface of the
vault
ī 2 sessions 1 week apart
īē Residual disease
ī CTV of 2 cm given to gross tumor and the
prescription of 8500cgy encompassing the
whole CTV is made
ī 2 sessions 1 week apart
ī§ Mostly after EBRT
50. POST OP BRACHYTHERAPY
ī§ CONTRAINDICATIONS
īē Vaginal wall involvement ( middle- lower 13)
īē Heavy parametrium infiltration
īē VVF or VRF
īē Inadequate space
īē Medical contraindications
īē Metastatic disease
ī§ Supplementary radiation 2000 cGy 10fr
51. SURFACE MOULDS
Radiation is delivered by arranging RA
sources over the surface of tumor
ī§ Types
īē Planar
ī Circular
ī Square
ī Rectangular
īē Line source
īē Cylinder
52. INDICATIONS
ī§ Superficial /Accessible tumors
keloid : Sr90 , 20 gy in 4 fr after surgery.
ī§ Skin ca â HAM applicator, Freiburg flab are
surface template applicators, dose â 35 to 50
Gy in 5 to 10 fr.
ī§ Post mastectomy recurrence â LDR- 65 Gy in
2 to 3 fr,monthly intervals.
ī§ Oral tumor
īē hard palate ,alveolus,oral cavity,lip
īē as a sole modality 60 GY,as boost to 45 to 50 GY-
15 TO 30 Gy.
ī§ Penile carcinoma
53. INTRALUMINAL BRACHYTHERAPY
ī§ Radioactive source is passed through a tube and
passed into a hollow lumen
ī§ Sites
īē 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..
īē Bronchus : Bronchogenic carcinoma
ī 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
ī Palliative :
ī
ī
ī
ī
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
ī§ Ind â unresectable tumors
ī§ Technique â endoscopic retrograde technique
ī§ BT delivered throug a transhepatic
cholangiogram
ī§ TV- tumor +1 to 2 cm proximal and distal
margin
ī§ Monotherapy- palliative dose 30 gy in 6 fr
ī§ As boost(45 Gy EBRT) â 15 TO 20 Gy in 3 to 4
fr.
56. Intra vascular
brachytherapy
Coronary artery disease caused
by occlusion of cardiac vessels
ī§ IVB used to prevent restenosis
after angioplasty
ī§ Radiation delivered either with
temporary implant or radioactive
stent
ī§
57. Intra operative Radiation
brachytherapy
ī§ Attractive for deep tumors
because the skin dose was
limiting prior to the invention
of megavoltage accelerators.
ī§ Applications include:
retroperitoneal
sarcoma, pancreatic cancer,
rectal cancer, pediatric
tumors,malignant thoracic
tumors.
ī§ dose of 10 to 20 Gy in single
fr over 10 to 30 minutes.
58. Image guided brachytherapy
ī§ 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.
ī§ 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. IGBTâĻ
ī§ 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.
ī§ MR is an ideal image guidance modality
for image guided brachytherapy.
Outstanding visualization of pelvic
60. Adaptive Brachytherapy
ī§ 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.
ī§ Plans are altered throughout the treatment
course for every course of treatment depending
on tumor volume.
ī§ Patient setup and organ motion obtained from
imaging during treatment to alter the treatment
plan.
61. ROBOTIC BRACHYTHERAPY
ī§ Improve accuracy of needle placement
and seed delivery
ī§ Improve consistency of seed implant
ī§ Improve avoidance of critical structures
ī§ Reduce radiation exposure
ī§ MAINLY USED FOR CA PROSTATE
ī§ Seed placement error is at sub millimeter
level.
62. Intensity modulated
brachytherapy
ī§ 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.
ī§ Intensity modulated sources based on Monte Carlo
simulations
ī§ a âmodified TG43â (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
ī§ an inverse IMBT treatment planning method based on Dose
Volume Histogram (DVH) or Dose Surface Histogram (DSH)
constraints and simulated annealing optimization algorithm.