clinical applications of LDR-HDR brachytheray

1. CLINICAL APPLICATIONS
OF LDR-HDR
BRACHYTHERAPY
DR. SUGASHWARAN. J,
MODERATOR:PROF.DR.G. V. GIRI,
DEPT. OF RADIATION ONCOLOGY,
KMIO, BANGALORE.

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

8. CLASSIFICATION
 SURGICAL APPROACH
/ POSITIONING
 SOURCE IN TUMOR




INTERSTITIAL
INTRACAVITARY
INTRALUMINAL
ENDOVASCULAR
 SOURCE IN CONTACT
BUT SUPERFICIAL
 SURFACE
BRACHYTHERAPY/
MOULD
 DURATION OF
IRRADIATION
 TEMPORARY-Cs137,Ir192
 PERMANENT-I125,Au198
Pd 103 .Cs 131

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

12. RADIOBIOLOGY
 Biological effects depend on
 Prescribed dose
 Treated volume
 Dose rate
 Fractionation
 Treatment duration

13. RADIOBIOLOGY – 4 Rs




Repair
Reassortment / redistribution
Repopulation
Reoxygenation

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

22. CLINICAL APPLICATIONS…
Oral Tongue:
 Indications: T1 N0, T2 N0 < 3cm lesion
 T.V.: GTV + 5 mm margin
 Dose: Alone:60-65 Gy LDR
 Boost 20-25 Gy after EBRT dose of 45-50 Gy
 Techniques: Guide-gutter technique
AP X-ray

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

43. CLINICAL APPLICATIONS…
 PERINEAL IMPLANTS
Martinez Universal Perineal
Interstitial Template
(MUPIT)
Syed-Neblett template

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.