clinical applications of ldr and hdr brachytherapy
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clinical applications of LDR-HDR brachytheray

clinical applications of LDR-HDR brachytheray

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clinical applications of ldr and hdr brachytherapy clinical applications of ldr and hdr brachytherapy Presentation Transcript

  • CLINICAL APPLICATIONS OF LDR-HDR BRACHYTHERAPY DR. SUGASHWARAN. J, MODERATOR:PROF.DR.G. V. GIRI, DEPT. OF RADIATION ONCOLOGY, KMIO, BANGALORE.
  • BRACHYTHERAPY  Type of radiation treatment  Consists of placing sealed radioactive sources very close to or in contact with the target tissue.
  • 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
  • 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     
  • 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)
  • 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
  • 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
  • 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
  • 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
  • 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
  • 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
  • RADIOBIOLOGY  Biological effects depend on  Prescribed dose  Treated volume  Dose rate  Fractionation  Treatment duration
  • RADIOBIOLOGY – 4 Rs     Repair Reassortment / redistribution Repopulation Reoxygenation
  • 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
  • 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)
  • 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
  • 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
  • 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
  • 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
  • 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
  • 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
  • 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
  • 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
  • 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.
  • 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
  • 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
  • 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
  • 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
  • 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.
  • 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.
  • NEW ELLIPTICAL BALOON(2004)  Provides excellent conformance  Ellipsoidal implant parellel to the chest wall provides appropriate symmentry
  • 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
  • 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)
  • 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
  • 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)
  • 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
  • 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
  • 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
  • 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
  • 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
  • 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
  • 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
  • CLINICAL APPLICATIONS…  PERINEAL IMPLANTS Martinez Universal Perineal Interstitial Template (MUPIT) Syed-Neblett template
  • 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.
  • INTRACAVITARY APPLICATION  Radioactive sources are placed in a existing cavity usually inside a predefined applicator with special geometry  Uses:  Cervix  Endometrium  Vagina  Maxilla  Nasopharynx
  • 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
  • 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
  • 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
  • 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
  • SURFACE MOULDS Radiation is delivered by arranging RA sources over the surface of tumor  Types  Planar  Circular  Square  Rectangular  Line source  Cylinder
  • 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
  • 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.
  • 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
  • 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.
  • 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 
  • 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.
  • 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.
  • 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
  • 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.
  • 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.
  • 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.