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Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
Brachytherapy Final
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Brachytherapy Final

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    • 1. <ul><li>DR. MANOJ KUMAR B </li></ul><ul><li>MODERATOR:PROF. S.C. SHARMA </li></ul><ul><li>DEPTT. OF RADIOTHERAPY AND ONCOLOGY </li></ul><ul><li>PGIMER,CHANDIGARH </li></ul>BRACHYTHERAPY PRINCIPLE AND METHODS
    • 2. BRACHYTHERAPY <ul><li>Type of radiation treatment in which radioactive sources are arranged in such a fashion that radiation is delivered to the tumor at a short distance by interstitial, intracavitary or surface application. </li></ul>
    • 3. CLINICAL ADVANTAGES <ul><li>High biological efficacy </li></ul><ul><li>Rapid dose fall-off </li></ul><ul><li>High tolerance </li></ul><ul><li>Tolerable acute intense reaction </li></ul><ul><li>Decreased risk of tumor population </li></ul><ul><li>High control rate </li></ul><ul><li>Better cosmesis </li></ul><ul><li>Minimal radiation morbidity </li></ul><ul><li>Day care procedure </li></ul>
    • 4. LIMITATIONS & DISADVANTAGES <ul><li>Difficult for inaccessible regions </li></ul><ul><li>Limited for small tumors (T 1 _T 2 ) </li></ul><ul><li>Invasive procedures, require GA </li></ul><ul><li>Higher dose inhomogeneity </li></ul><ul><li>Greater conformation –small errors in placement of sources lead to extreme changes from the intended dose distribution </li></ul><ul><li>Radioactive hazards (not now) </li></ul><ul><li>Costly </li></ul>
    • 5. SELECTION CRITERIA <ul><li>Easily accessible lesions </li></ul><ul><li>Early stage diseases (Ideal implant ≤ 5 cm) </li></ul><ul><li>Well localized tumor to organ of origin </li></ul><ul><li>No nodal or distant metastases </li></ul><ul><li>No local infections or inflammation </li></ul><ul><li>Favorable histology- mod. diff. i.e. SCC </li></ul><ul><li>Non DM / HTN </li></ul><ul><li>Proliferative/ ulcerative lesions preferred </li></ul>
    • 6. INDICATIONS <ul><li>RADICAL RADIATION </li></ul><ul><ul><li>Skin malignancies- BCC, SCC </li></ul></ul><ul><ul><li>Head & neck cancers </li></ul></ul><ul><ul><li>Ca cx </li></ul></ul><ul><ul><li>Ca prostate </li></ul></ul><ul><li>BOOST AFTER EXT.RT±CCT </li></ul><ul><ul><li>Head & neck cancers </li></ul></ul><ul><ul><li>Ca Breast </li></ul></ul><ul><ul><li>Esophagus </li></ul></ul><ul><ul><li>Anal canal </li></ul></ul>
    • 7. INDICATIONS... <ul><li>PERIOPERTIVE </li></ul><ul><ul><li>STS </li></ul></ul><ul><ul><li>Ca Breast </li></ul></ul><ul><li>POSTOP </li></ul><ul><ul><li>Ca Endometrium </li></ul></ul><ul><ul><li>Ca cx </li></ul></ul><ul><ul><li>Ca Breast </li></ul></ul><ul><li>PALLIATIVE </li></ul><ul><ul><li>Bronchogenic Ca </li></ul></ul><ul><ul><li>Biliary duct malignancy </li></ul></ul><ul><ul><li>Ca Esophagus </li></ul></ul><ul><ul><li>Recurrent tumors </li></ul></ul><ul><li>BENIGN </li></ul><ul><ul><li>Keloids / Pterygium </li></ul></ul><ul><li>OTHERS </li></ul><ul><ul><li>Endovascular/Rad. stent </li></ul></ul>
    • 8. CLASSIFICATION Classification Schemes Positioning of Radionuclide Dose rate of irradiation Duration of irradiation Loading pattern
    • 9. CLASSIFICATION <ul><li>SURGICAL APPROACH / POSITIONING </li></ul><ul><ul><li>SOURCE IN TUMOR </li></ul></ul><ul><ul><ul><li>INTERSTITIAL </li></ul></ul></ul><ul><ul><ul><li>INTRACAVITARY </li></ul></ul></ul><ul><ul><ul><li>INTRALUMINAL </li></ul></ul></ul><ul><ul><ul><li>ENDOVASCULAR </li></ul></ul></ul><ul><ul><li>SOURCE IN CONTACT BUT SUPERFICIAL </li></ul></ul><ul><ul><ul><li>SURFACE BRACHYTHERAPY/ MOULAGE </li></ul></ul></ul><ul><li>DURATION OF IRRADIATION </li></ul><ul><ul><li>TEMPORARY-Cs 137 ,Ir 192 </li></ul></ul><ul><ul><li>PERMANENT-I 125 ,Au 198 </li></ul></ul>
    • 10. DOSE RATE(ICRU 38) <ul><li>LOW DOSE RATE (LDR) </li></ul><ul><ul><li>0.4-2 Gy/hr </li></ul></ul><ul><ul><li>Bed confinement </li></ul></ul><ul><ul><li>LDR A/L : Cs 137 </li></ul></ul><ul><li>MEDIUM DOSE RATE (MDR) </li></ul><ul><ul><li>2-12 Gy/hr </li></ul></ul><ul><li>HIGH DOSE RATE (HDR) </li></ul><ul><ul><li>> 12 Gy/hr </li></ul></ul><ul><li>ULTRA LOW DOSE RATE </li></ul><ul><ul><li>0.01-0.3 Gy/hr </li></ul></ul><ul><li>ROUGHLY </li></ul><ul><ul><li>LDR – 10 Gy/day </li></ul></ul><ul><ul><li>MDR -10 Gy/hr </li></ul></ul><ul><ul><li>HDR – 10 Gy/min </li></ul></ul>
    • 11. ADVANTAGES <ul><li>LDR </li></ul><ul><li>HDR </li></ul><ul><li>Predictable clinical effects </li></ul><ul><li>Superior radiobiological role </li></ul><ul><li>Less morbidity, control is best </li></ul><ul><li>Well practised since long </li></ul><ul><li>Minimum intersession variability in dose distribution </li></ul><ul><li>SHORT T/T TIME </li></ul><ul><ul><li>Geometry well maintained </li></ul></ul><ul><ul><li>Better patient compliance / comfort </li></ul></ul><ul><ul><li>Day care procedure </li></ul></ul><ul><li>OPTIMIZATION </li></ul><ul><li>NO RADIATION HAZARDS </li></ul><ul><li>SMALL APPLICATOR </li></ul><ul><ul><li>Less tissue trauma </li></ul></ul><ul><ul><li>Better packing </li></ul></ul>
    • 12. MDR BRACHYTHERAPY <ul><li>ADVANTAGES </li></ul><ul><ul><li>Comparative shorter T/T time </li></ul></ul><ul><ul><li>One time treatment can be used </li></ul></ul><ul><ul><li>Patient convenience </li></ul></ul><ul><ul><li>Radio biologically acceptable nearer to LDR Brachytherapy </li></ul></ul><ul><li>DISADVANTAGES </li></ul><ul><ul><li>Late complications increases if correction not done </li></ul></ul>
    • 13. SOURCE LOADING TECHNIQUE <ul><li>PRELOADING SYSTEM </li></ul><ul><ul><li>Live sources </li></ul></ul><ul><ul><li>ADVANTAGES </li></ul></ul><ul><ul><ul><li>Clinical results are best </li></ul></ul></ul><ul><ul><ul><li>Affordable </li></ul></ul></ul><ul><ul><ul><li>Long term results with lesser morbidities </li></ul></ul></ul><ul><ul><li>DISADVANTAGES </li></ul></ul><ul><ul><ul><li>Radiation hazards </li></ul></ul></ul><ul><ul><ul><li>Special instruments </li></ul></ul></ul><ul><ul><ul><li>Difficult application / hasty </li></ul></ul></ul><ul><ul><ul><li>Geometry not maintained </li></ul></ul></ul><ul><ul><ul><li>? Optimization </li></ul></ul></ul>
    • 14. AFTER LOADING TECHNIQUE <ul><li>MANUAL </li></ul><ul><ul><li>Avoids radiation protection issue of preloading </li></ul></ul><ul><ul><li>Better applicator placement </li></ul></ul><ul><ul><li>Verification prior to source placement </li></ul></ul><ul><ul><li>Min. radiation hazard </li></ul></ul><ul><ul><li>Advantages of preloading </li></ul></ul><ul><li>REMOTE CONTROLLED </li></ul><ul><ul><li>No radiation hazard </li></ul></ul><ul><ul><li>Accurate placement </li></ul></ul><ul><ul><li>Geometry maintained </li></ul></ul><ul><ul><li>Better dose distribution </li></ul></ul><ul><ul><li>Highly precise </li></ul></ul><ul><ul><li>Short T/T time </li></ul></ul><ul><ul><li>Day care procedure </li></ul></ul><ul><ul><li>Mainly used for HDR </li></ul></ul>
    • 15. INTERSTITIAL BRACHYTHERAPY <ul><li>Sealed Radioactive sources directly implanted into the tumor in a geometric fashion </li></ul><ul><li>First suggested by Alexander Graham Bell </li></ul><ul><li>ADVANTAGES </li></ul><ul><ul><li>Higher local dose in shorter time </li></ul></ul><ul><ul><li>Rapid dose fall </li></ul></ul><ul><ul><li>Better tumor control </li></ul></ul><ul><ul><li>Lesser radiation morbidities </li></ul></ul><ul><ul><li>Superior cosmetics </li></ul></ul><ul><ul><li>Functional preservation of organs </li></ul></ul>
    • 16. INTERSTITIAL BRACHYTHERAPY… <ul><li>DISADVANTAGES </li></ul><ul><ul><li>Radiation hazards in older days </li></ul></ul><ul><ul><li>Costly </li></ul></ul><ul><ul><li>Not applicable to inaccessible areas </li></ul></ul><ul><li>INTENTION OF TREATMENT </li></ul><ul><ul><li>Always RADICAL </li></ul></ul><ul><ul><ul><li>As radical brachytherapy alone (smaller lesions) </li></ul></ul></ul><ul><ul><ul><li>Local boost in combination with EBRT (larger lesion) </li></ul></ul></ul><ul><ul><ul><li>NEVER USED FOR PALLIATION </li></ul></ul></ul>
    • 17. SELECTION CRITERIA <ul><li>Easily accessible lesions, at least from one side </li></ul><ul><li>Early stage disease </li></ul><ul><ul><li>T 1 -T 2 and sometimes early T 3 </li></ul></ul><ul><ul><li>Ideally total size of implant ≤ 5 cm </li></ul></ul><ul><li>Non DM /HTN </li></ul><ul><li>No local infection </li></ul><ul><li>Proliferative and ulcerative lesions preferred </li></ul>
    • 18. CLINICAL APPLICATIONS <ul><li>Head & neck tumors </li></ul><ul><ul><li>Early stage oropharyngeal cancers </li></ul></ul><ul><li>Ca breast- Boost /PBI </li></ul><ul><li>Ca prostate </li></ul><ul><li>Soft tissue sarcoma </li></ul><ul><li>Gynecologic malignancies </li></ul><ul><li>Ca anal canal and rectum </li></ul><ul><li>Ca lung and pancreas </li></ul>
    • 19. TYPES OF INTERSTITIAL IMPLANTS ACCORDING TO SIZE/LOCATION/PROXIMITY OF TUMOR TO NORMAL STRUCTURES <ul><li>TEMPORARY </li></ul><ul><ul><li>Radioactive sources removed after desirable dose has been delivered </li></ul></ul><ul><ul><li>Rigid stainless steel needles/flexible Teflon / nylon guides/plastic tubes </li></ul></ul><ul><ul><li>Preloaded/After loaded </li></ul></ul><ul><li>PERMANENT </li></ul><ul><ul><li>Preloaded – rigid needle eg. Ra 226 ,Cs 137 </li></ul></ul><ul><ul><li>After loaded – Manual/ Remote </li></ul></ul><ul><ul><li>Advantages </li></ul></ul><ul><ul><ul><li>Flexibility of implant design </li></ul></ul></ul><ul><ul><ul><li>Reduction of radiation exposure levels resulting in more accurate placement of needles and guides </li></ul></ul></ul>
    • 20. SYSTEMS OF IMPLANT DOSIMETRY <ul><li>OBJECTIVES OF TREATMENT PLANNING </li></ul><ul><ul><li>To determine the distribution & type of radiation sources to provide optimum dose distribution </li></ul></ul><ul><ul><li>To provide complete dose distribution in irradiated volume </li></ul></ul><ul><li>SYSTEM USED </li></ul><ul><ul><li>Paterson-Parker (Manchester) system </li></ul></ul><ul><ul><li>Quimby system (Memorial) system </li></ul></ul><ul><ul><li>Paris system – Pierquin, Chassagne , Dutreix and Marinello </li></ul></ul><ul><ul><li>Computer System </li></ul></ul>
    • 21. SYSTEMS OF IMPLANT DOSIMETRY <ul><li>These system designed during times when computers were not available for routine planning </li></ul><ul><li>Extensive table & elaborate rules of source distribution were devised to facilitate the process of manual treatment planning </li></ul><ul><li>These systems differ in rule of implantation, definition of dose uniformity & method used in reference dose specification </li></ul>
    • 22. RULES OF INT.IMPLANT SYSTEM PARAMETERS MANCHESTER QUIMBY PARIS COMPUTER Linear strength Variable Constant Constant Constant Source distribution Planar implant:(periphery) Area <25 cm- 2/3 Ra; 25-100 cm- ½ Ra; >100 cm- 1/3 Volume implant::Cylinder:belt-4 parts,core-2,end-1 Sphere:shell-6,core-2 Cube :each side-1,core-2 Uniform Uniform Uniform Line sources parallel planes Uniform Line sources Parallel or cylinderic volumes Spacing line source Constant approx. 1 cm apart from each other or from crossing ends Same as Manchester Constant, Selective Separation 8-15 mm Constant Selective Crossing needles Required to enhance dose at implant ends Same Crossing needles not used;active length 30-40% longer Crossing needles not used;active length 30-40% longer
    • 23. COMPONENTS-CLASSICAL SYSTEM <ul><li>DISTRIBUTION RULES : given a target volume, distribution rules determine how to distribute RA sources & applicators in & around target volume </li></ul><ul><li>DOSE SPECIFICATION & IMPLANT OPTIMIZATION CRITERIA : Each system has a definition of prescribed dose </li></ul><ul><li>Above 2 criteria determine dose homogeneity, normal tissue sparing, no. of catheters implanted & margins around target </li></ul><ul><li>DOSE CALCULATION AIDS : Older systems used tables that give dose delivered per mg Ra-Eq-hr as a function of treatment volume or area </li></ul><ul><ul><li>Recent Paris system uses computerized treatment planning to relate absorbed dose to source strength & treatment time </li></ul></ul>
    • 24. PRINCIPLE-MANCHESTER SYSTEM FEATURES DOSE & DOSE RATE 6000-8000 R in 6-8 days (1000 R/day; 40 R/hr) UNIT / USE OF RADIUM mg Ra hr – defined as amount of radium to give specified dose in 1 hr DOSE SPECIFICATION CRITERA Effective minimum dose 10% above absolute minimum dose LINEAR ACTIVITY Variable: 0.66 and 0.33 mg RaEq/cm
    • 25. QUIMBY SYSTEM <ul><li>Developed by Edith Quimby et al </li></ul><ul><li>Dose 5000-6000 R in 3-4 days </li></ul><ul><li>Equal linear intensity (mg RaEq/cm) needles distributed uniformly (fixed spacing) in each implant, although spacing selected in 1-2 cm range acc. to implant size </li></ul><ul><li>Quimby tables (Nomogram ) give mg RaEq-hr to deliver stated exposure of 1000 R as function of T.V. or area (5000-6000 R over 3-4 days; 60-70 R/hour) </li></ul><ul><li>No clear description of rules for distributing Ra needles </li></ul><ul><li>Crossing recommended; peripheral needles placed on or beyond T.V. boundaries </li></ul><ul><li>Dose specification criteria inconsistent </li></ul><ul><li>NOT RECOMMENDED FOR CLINICAL USE </li></ul>
    • 26. PARIS SYSTEM- PRINCIPLES <ul><li>RADIOACTVE SOURCES </li></ul><ul><li>Rectilinear/parallel -arrangement so that centers are located in the same plane which is perpendicular to the direction of sources- CENTRAL PLANE </li></ul><ul><li>Equidistant </li></ul><ul><li>Linear activity-uniform and identical </li></ul><ul><li>Source geometries </li></ul><ul><ul><li>Linear- single-plane implants </li></ul></ul><ul><ul><li>Squares/Equilateral triangles- two plane implants </li></ul></ul>
    • 27. PARIS SYSTEM FEATURES DOSE AND DOSE RATE 6000 -7000 cGy in 3-11 days DOSE PRESCRIPTION POINT Average of the minimum doses in the region defined by the source REFERENCE DOSE & DOSE GRADIENT 85 % of the BASAL DOSE 15 % between the Reference dose and the Basal dose RA SOURCE PLACEMENT Reference isodose volume covers the treated volume
    • 28. PERMANENT IMPLANTS <ul><li>ADVANTAGES </li></ul><ul><li>DISADVANTAGES </li></ul><ul><ul><li>Less accessible sites </li></ul></ul><ul><ul><li>Cont. ultra low dose rate>Max biological effectiveness </li></ul></ul><ul><ul><li>Better tissue heal </li></ul></ul><ul><ul><li>Better effect in slow and radio resistant tumors </li></ul></ul><ul><ul><li>Improved mobility </li></ul></ul><ul><ul><li>Environmental issue </li></ul></ul><ul><ul><li>Dosimetric uncertainties > Later part of T/T becomes less effective </li></ul></ul><ul><ul><li>Source displacement </li></ul></ul><ul><ul><li>Large tumor > Difficult procedure and geometry </li></ul></ul><ul><ul><li>Radio biologically less effective for rapidly proliferating tumors </li></ul></ul>
    • 29. COMPUTER SYSTEM <ul><li>Implant system evolved through use of computers </li></ul><ul><li>Implantation rules: Sources of uniform strength </li></ul><ul><li>Spaced uniformly (1-1.5 cm), larger spacing for larger implants to cover entire T.V. </li></ul><ul><li>Active length 30-40% longer than Target length as ends uncrossed </li></ul><ul><li>T.V.: sufficient safety margins; peripheral sources implanted on outer surface </li></ul><ul><li>Dose specified by isodose surface that surrounds target </li></ul><ul><li>Whole planning with help of computers </li></ul>
    • 30. COMPUTER DOSIMETRY <ul><li>Possible to preplan implants & complete isodose distribution corresponding to final source distribution </li></ul><ul><li>Rapid & fast; helps modify implant </li></ul><ul><li>Isodose patterns can be magnified & superimposed on implant radiograph </li></ul><ul><li>Localization of sources: </li></ul><ul><ul><li>Orthogonal Imaging method </li></ul></ul><ul><ul><li>Stereo-shift method </li></ul></ul><ul><ul><li>CT </li></ul></ul><ul><li>Dose Calculation: </li></ul><ul><ul><li>No. of milligrams or millicurie in implant </li></ul></ul><ul><ul><li>Location of each source with respect to dose calculation point </li></ul></ul><ul><ul><li>Type of isotope being used </li></ul></ul><ul><ul><li>Filtration of the encapsulation </li></ul></ul>
    • 31. COMPUTER DOSIMTERY <ul><li>Dose Computation: </li></ul><ul><ul><li>Dose calculation Formalisms’ (AAPM TG 43 algorithm) </li></ul></ul><ul><ul><ul><li>Use Sievert Integral directly </li></ul></ul></ul><ul><ul><ul><li>Precalculated dose tables </li></ul></ul></ul><ul><ul><ul><ul><li>For Radium & other long lived sources: Dose rates in form of isodose curves </li></ul></ul></ul></ul><ul><ul><ul><ul><li>For Iridium & relatively short lived implants: Computer calculates cumulative dose with decay correction </li></ul></ul></ul></ul>
    • 32. CLINICAL APPLICATIONS <ul><li>Oral Cavity: </li></ul><ul><li>LIP: </li></ul><ul><ul><li>Indications: T1-2N0 Lesions </li></ul></ul><ul><ul><li>T.V.: All visible & palpable tumour with 5-10 mm margin </li></ul></ul><ul><ul><li>Dose: 50-70Gy in 5-7 days LDR </li></ul></ul><ul><ul><li>Technique: </li></ul></ul><ul><ul><ul><li>Rigid afterloading needles maintained in place by Template </li></ul></ul></ul><ul><ul><ul><li>Classical plastic tubes </li></ul></ul></ul><ul><ul><li>Spacers to decrease dose to gingiva, teeth & other lip </li></ul></ul>
    • 33. CLINICAL APPLICATIONS… <ul><li>Buccal Mucosa: </li></ul><ul><ul><li>Indications: </li></ul></ul><ul><ul><ul><li>Brachytherapy alone indicated for small (<4cm), well-defined lesions in anterior 2/3 rd </li></ul></ul></ul><ul><ul><ul><li>As boost after EBRT for larger lesions </li></ul></ul></ul><ul><ul><li>T.V.: GTV + margins </li></ul></ul><ul><ul><li>Dose: Alone 65-70 Gy </li></ul></ul><ul><ul><ul><ul><li>Boost 25-30 Gy </li></ul></ul></ul></ul><ul><ul><li>Technique: Guide Gutter Technique: Lesion < 2cm </li></ul></ul><ul><ul><li>Plastic tube technique : For other lesions </li></ul></ul>
    • 34. CLINICAL APPLICATIONS… <ul><li>Oral Tongue: </li></ul><ul><li>Indications: T1 N0, T2 N0 < 3cm lesion </li></ul><ul><li>T.V.: GTV + 5 mm margin </li></ul><ul><li>Dose: Alone:60-65 Gy LDR </li></ul><ul><ul><ul><li>Boost 20-25 Gy after EBRT dose of 45-50 Gy </li></ul></ul></ul><ul><li>Techniques: Guide-gutter technique </li></ul>AP X-ray
    • 35. CLINICAL APPLICATIONS… <ul><li>Floor of Mouth : </li></ul><ul><ul><li>Indications: T1-2N0 lesions, ≥ 5 mm away from mandible </li></ul></ul><ul><ul><li>Dose: Techniques same as for Tongue implants </li></ul></ul><ul><ul><li>Complication: Osteoradionecrosis:5-15% </li></ul></ul><ul><li>Oropharynx: </li></ul><ul><ul><li>Indications: Ca BOT , soft palate, tonsillar fossa & vallecula usually as boost after EBRT </li></ul></ul><ul><ul><ul><li>Lesions < 5 cm (after EBRT) </li></ul></ul></ul><ul><ul><li>T.V.: GTV + 10 mm margin </li></ul></ul><ul><ul><li>Dose: Tonsillar fossa-25-30 Gy; BOT 30-35 Gy </li></ul></ul><ul><ul><li>Technique: Classical Plastic Loop technique </li></ul></ul>
    • 36. CLINICAL APPLICATIONS… <ul><li>Breast </li></ul><ul><ul><li>Indications: Boost after BCS & EBRT </li></ul></ul><ul><ul><ul><ul><ul><li>Postoperative interstitial irradiation alone of </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>the primary tumor site after BCS in selected </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>low risk T1 and small T2N0 (PBI) </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Chest wall recurrences </li></ul></ul></ul></ul></ul>Moderator: Prof. S. C. Sharma As sole modality As Boost to EBRT <ul><li>Patient choice: cannot come for 5-6 wks treatment : </li></ul><ul><ul><ul><li>Distance </li></ul></ul></ul><ul><ul><ul><li>Lack of time </li></ul></ul></ul>Close, positive or unknown margins Elderly, frail, poor health patient EIC Large breasts: unacceptable toxicity Younger patients Deep tumour in large breast Irregularly thick target vol.
    • 37. CLINICAL APPLICATIONS… <ul><li>T.V.: Primary Tumor site + 2-3 cm margin </li></ul><ul><li>Dose: As Boost: 10-20 Gy LDR </li></ul><ul><ul><ul><li>AS PBI: 45-50 Gy in 4-5 days LDR (30-70 cGy/hour) </li></ul></ul></ul><ul><ul><ul><ul><ul><li>34 Gy/10#, 2# per day HDR </li></ul></ul></ul></ul></ul><ul><li>Technique: </li></ul><ul><ul><li>Localization of PTV: Surgical clips (at least 6) </li></ul></ul><ul><ul><ul><li>USG, CT or MRI localization, Intraop USG </li></ul></ul></ul><ul><ul><li>During primary surgery </li></ul></ul><ul><ul><li>Guide needle technique or </li></ul></ul><ul><ul><li>Plastic tube technique using Template </li></ul></ul><ul><ul><ul><li>Double plane implant </li></ul></ul></ul><ul><ul><ul><li>Skin to source distance: Minimum 5 mm </li></ul></ul></ul>
    • 38. CLINICAL APPLICATIONS…
    • 39. CLINICAL APPLICATIONS… <ul><li>Prostate: </li></ul><ul><li>Indications </li></ul><ul><ul><li>Brachytherapy as monotherapy: </li></ul></ul><ul><ul><ul><li>Stage T1-2a & Gleason score 2-6 & PSA ≤ 10 ng/ml </li></ul></ul></ul><ul><ul><li>As boost after EBRT </li></ul></ul><ul><ul><ul><li>Stage T2b, T2c or Gleason score 7-10 or PSA > 10 ng/ml </li></ul></ul></ul><ul><ul><li>For brachytherapy, Prostate size < 50 cc </li></ul></ul><ul><li>Exclusion criteria: </li></ul><ul><ul><li>Life expectancy < 5 yrs </li></ul></ul><ul><ul><li>Large or poorly healed TURP defect </li></ul></ul><ul><ul><li>Distant Mets or operative risk </li></ul></ul><ul><li>T.V.: Whole prostate within capsule + 2-3 mm margin </li></ul><ul><li>Methods: Permanent Implant (I 125 or Pd 103 ) or </li></ul><ul><li>Temporary Implant (Ir 192 ) </li></ul>
    • 40. CLINICAL APPLICATIONS… <ul><li>Technique for Permanent implant </li></ul><ul><li>Retropubic approach with I 125 seeds- Disappointing results </li></ul><ul><li>Modern technique: Transperineal Approach </li></ul><ul><ul><li>TRUS guided </li></ul></ul><ul><ul><li>Two step approach </li></ul></ul><ul><ul><ul><li>Volume study of prostate </li></ul></ul></ul><ul><ul><li>Computer planning </li></ul></ul><ul><ul><ul><li>Seed positioning </li></ul></ul></ul><ul><li>Coverage check -USG & Flouroscopy </li></ul><ul><li>Check Cystoscopy </li></ul><ul><li>Post-implant image based dosimetry </li></ul>
    • 41. CLINICAL APPLICATIONS <ul><li>Dose: </li></ul><ul><ul><li>I 125 : 145 Gy as sole RT </li></ul></ul><ul><ul><ul><ul><li>100-110 Gy as boost to 40-50 Gy EBRT </li></ul></ul></ul></ul><ul><ul><li>Pd 103 : 125 Gy as sole RT </li></ul></ul><ul><ul><ul><ul><li>90-100 Gy as boost to 40-50 Gy EBRT </li></ul></ul></ul></ul><ul><li>Temporary Implants with Ir 192 (LDR or HDR): </li></ul><ul><ul><li>Procedure same as above; lesser no. of plastic catheters required (8-15) </li></ul></ul><ul><ul><li>Dose: </li></ul></ul><ul><ul><ul><li>LDR 30-35 Gy seeds left for 3 days(Boost to 45 Gy EBRT) </li></ul></ul></ul><ul><ul><ul><li>HDR 20-25 Gy, 4-6 Gy/#(Boost to 45 Gy EBRT) </li></ul></ul></ul>
    • 42. CLINICAL APPLICATIONS <ul><li>Soft tissue Sarcomas (using Ir 192 or I 125 ) </li></ul><ul><li>Indications: </li></ul><ul><ul><li>As sole postop RT: </li></ul></ul><ul><ul><ul><li>completely resected intermediate or high grade tumours of extremity or superficial trunk with -ve margins </li></ul></ul></ul><ul><ul><li>As boost to postop EBRT: </li></ul></ul><ul><ul><ul><li>Intermediate or high grade sarcoma with +/- margins </li></ul></ul></ul><ul><ul><ul><li>Postop pts with small lesions & +ve/uncertain margins </li></ul></ul></ul><ul><ul><ul><li>Deep lesions </li></ul></ul></ul><ul><ul><ul><li>Low grade sarcomas </li></ul></ul></ul><ul><li>T.V.: GTV + 2-5 cm margin </li></ul><ul><ul><ul><li>GTV based on preop MRI & clinical findings </li></ul></ul></ul><ul><li>Dose: LDR (Ir seeds or wires) as sole treatment 45-50 Gy in 4-6 days </li></ul><ul><ul><ul><li>As boost to 45-50 Gy EBRT: 15-25 Gy in 2-3 days </li></ul></ul></ul>
    • 43. CLINICAL APPLICATIONS… <ul><li>Technique: </li></ul><ul><ul><li>Usually performed at time of surgery </li></ul></ul><ul><ul><li>Basic or sealed end temporary implant technique </li></ul></ul>
    • 44. <ul><li>Brain: Permanent or temporary (using I 125 or Ir 192 seeds/wires ) </li></ul><ul><li>Indications: </li></ul><ul><ul><li>As boost to EBRT or recurrence </li></ul></ul><ul><ul><li>Anaplastic astrocytoma or GBM, unifocal, well cicumscribed, peripheral lesions & < 5 cm in diameter </li></ul></ul><ul><li>T.V.: Contrast enhancing area on MRI +/- 5mm margin </li></ul><ul><li>Dose: LDR 50-60 Gy, 0.4-0.5 Gy/hr </li></ul><ul><li>Technique: Planning CT/MRI done </li></ul>CLINICAL APPLICATIONS…
    • 45. CLINICAL APPLICATIONS… <ul><li>Ca Anorectum </li></ul><ul><li>Indications: As boost to EBRT/ChemoRT </li></ul><ul><ul><ul><ul><li>If T.V. doesnot exceeds 1/2 circumference, 5 mm thick, 5 cm long i.e. T1-2 & small T3 lesions </li></ul></ul></ul></ul><ul><ul><ul><ul><li>T1N0 adenocarcinoma of rectum 3-10 cm above anus </li></ul></ul></ul></ul><ul><li>T.V.: Visible palpable tumor+5 mm </li></ul><ul><li>Dose: LDR 15-20 Gy at 0.3-0.6 Gy/hr </li></ul><ul><li>Technique: Guide needle technique with template </li></ul>
    • 46. CLINICAL APPLICATIONS… <ul><li>Gynecological Tumors ( Ir 192 LDR or HDR) </li></ul><ul><li>Indications: </li></ul><ul><ul><li>Ca Cervix </li></ul></ul><ul><ul><li>Ca Endometrium </li></ul></ul><ul><ul><ul><li>Postop local recurrence </li></ul></ul></ul><ul><ul><li>Ca Vagina & Vulva </li></ul></ul><ul><ul><ul><li>Radical BT in select early lesions (T1-2N0) </li></ul></ul></ul><ul><ul><ul><li>Boost after EBRT in large lesions (T2-3N1) </li></ul></ul></ul><ul><li>Technique: </li></ul><ul><ul><li>Guide-gutter technique </li></ul></ul><ul><ul><li>Blind plastic tube implant </li></ul></ul><ul><ul><li>(transperineal technique) </li></ul></ul><ul><ul><li>Plastic or guide needles </li></ul></ul>
    • 47. CLINICAL APPLICATION – CA CX <ul><ul><ul><li> ABS Recommendations </li></ul></ul></ul><ul><ul><ul><li>Bulky primary disease </li></ul></ul></ul><ul><ul><ul><li>Prior hysterectomy-inability to place tandem </li></ul></ul></ul><ul><ul><ul><li>Post hysterectomy </li></ul></ul></ul><ul><ul><ul><ul><li>vault recc./cut-through hysterectomy/cervical stump presentation </li></ul></ul></ul></ul><ul><ul><ul><li>Extesive parametrial involvement </li></ul></ul></ul><ul><ul><ul><li>Distorted anatomy </li></ul></ul></ul><ul><ul><ul><ul><li>Narrow vagina & fornices </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Extensive / Distal vaginal wall involvement </li></ul></ul></ul></ul><ul><ul><ul><li>Re-irradiation after recurrences </li></ul></ul></ul><ul><ul><ul><li>Prior course of RT to area of interest </li></ul></ul></ul>
    • 48. CLINICAL APPLICATIONS… <ul><ul><li>PERINEAL IMPLANTS </li></ul></ul>Martinez Universal Perineal Interstitial Template (MUPIT ) Syed-Neblett template
    • 49. CLINICAL APPLICATIONS… <ul><li>Dose: </li></ul><ul><ul><li>Radical BT: </li></ul></ul><ul><ul><ul><li>LDR: 55-60 Gy @ 50-90 cGy/hr </li></ul></ul></ul><ul><ul><ul><li>HDR: 3.5 Gy/#@ 2#/day/12-16# </li></ul></ul></ul><ul><ul><li>Boost </li></ul></ul><ul><ul><ul><li>LDR: 15-25 Gy , 50-90 cGy/hr </li></ul></ul></ul><ul><ul><ul><li>HDR: as above, no. of # depend upon EBRT doses </li></ul></ul></ul>
    • 50. CLINICAL APPLICATIONS… <ul><li>Other sites: </li></ul><ul><ul><li>Lung: Permanent perioperative BT, I 125 seeds, Au 198 Grains </li></ul></ul><ul><ul><ul><ul><li>Persistent or recurrent ds after EBRT or residual ds after surgery </li></ul></ul></ul></ul><ul><ul><li>Pancreas: Permanent perioperative BT, I 125 seeds </li></ul></ul><ul><ul><ul><ul><li>Locally advanced unresectable ds </li></ul></ul></ul></ul><ul><ul><li>Penis & Urethra: </li></ul></ul>
    • 51. INTRACAVITARY APPLICATION <ul><li>Radioactive sources are placed in a existing cavity usually inside a predefined applicator with special geometry </li></ul><ul><li>Uses: </li></ul><ul><ul><li>Cervix </li></ul></ul><ul><ul><li>Endometrium </li></ul></ul><ul><ul><li>Vagina </li></ul></ul><ul><ul><li>Maxilla </li></ul></ul><ul><ul><li>Nasopharynx </li></ul></ul>
    • 52. PARIS SYSTEM <ul><li>Single application of radium </li></ul><ul><li>Two cork colpostats (cylinder) and an intrauterine tube </li></ul><ul><li>Delivers a dose of 7000- 8000 mg-hrs of radium over a period of five days(45R/hr) (5500mg/hr </li></ul><ul><li>Equal amount of radium used in the uterus and the vagina </li></ul><ul><li>Intrauterine sources </li></ul><ul><ul><li>3 radioactive sources, with source strengths in the ratio of 1:1:0.5 </li></ul></ul><ul><li>colpostats </li></ul><ul><ul><li>sources with the same strength as the topmost uterine source </li></ul></ul>
    • 53. STOCKHOLM SYSTEM <ul><li>Fractionated course of radiation delivered over a period of one month. </li></ul><ul><li>Usually 2-3 applications, each for a period of 20- 30 hours (repeated 3weekly) </li></ul><ul><li>Intravaginal boxes -lead or gold intrauterine tube -flexible rubber </li></ul><ul><li>Unequal loading </li></ul><ul><ul><li>30 - 90 mg of radium in uterus </li></ul></ul><ul><ul><li>60 - 80 mg in vagina </li></ul></ul><ul><li>Total prescribed dose -6500-7100 mg Ra </li></ul><ul><ul><li>4500 mg Ra contributed by the vaginal box (dose rate-110R/hr or 2500mg/hr/#) </li></ul></ul>
    • 54. DRAWBACKS OF PARIS AND STOCKHOLM SYSTEMS <ul><li>Long treatment time </li></ul><ul><li>Discomfort to the patient </li></ul><ul><li>No dose prescription </li></ul>
    • 55. MANCHESTER SYSTEM <ul><li>To define the treatment in terms of dose to a point. Criteria of the point: </li></ul><ul><ul><li>Anatomically comparable </li></ul></ul><ul><ul><li>Position </li></ul></ul><ul><ul><ul><li>where the dosage is not highly sensitive to small alteration in applicator position </li></ul></ul></ul><ul><ul><ul><li>Allows correlation of the dose levels with the clinical effects </li></ul></ul></ul><ul><li>To design a set of applicators and their loading which would give the same dose rate irrespective of the combination of applicators used </li></ul><ul><li>To formulate a set of rules regarding the activity, relationship and positioning of the radium sources in the uterine tumors and the vaginal ovoids, for the desired dose rate </li></ul>
    • 56. POINT A <ul><li>PARACERVICAL TRIANGLE where initial lesion of radiation necrosis occurs </li></ul><ul><li>Area in the medial edge of broad ligament where the uterine vessel cross over the ureter </li></ul><ul><li>The point A -fixed point 2cm lateral to the center of uterine canal and 2 cm from the mucosa of the lateral fornix </li></ul><ul><li>POINT B </li></ul><ul><li>Rate of dose fall-off laterally </li></ul><ul><li>Imp. Calculating total dose-Combined with EBRT </li></ul><ul><li>Proximity to important OBTURATOR LNs </li></ul><ul><li>Same level as point A but 5 cm from midline </li></ul><ul><li>Dose ~20-25 % of the dose at point A </li></ul>
    • 57.  
    • 58. LOADING OF APPLICATORS <ul><li>In order that point A receives same dosage rate no matter which ovoid combination is used ,it is necessary to have different radium loading for each applicator size </li></ul><ul><li>Dose rate 57.5 R/hr to point A </li></ul><ul><li>Not more than 1/3 dose to point A must be delivered from vaginal radium </li></ul><ul><li>APPLICATORS </li></ul>
    • 59. LOADING PATTERN TUBE TYPE LENGTH TUBES RADIUM (mg) UNITS (FUNDUS to CX) LOADING TUBES (mg) LARGE 6 3 35 6-4-4 15-10-10 MEDIUM 4 2 25 6-4 15-10 SMALL 2 1 20 8 20 VAGINAL OVOIDS TUBES RADIUM (mg) UNITS LOADING TUBES(mg) LARGE 3 22.5 9 10-10-5 or 20/25 MEDIUM 2 20 8 20 SMALL 1 17.5 7 10-5-5 or 20/15
    • 60. GUIDELINES <ul><li>Largest possible ovoid </li></ul><ul><ul><li>Lesser dose to mucosa </li></ul></ul><ul><li>Longest possible tandem (not > 6 cm) </li></ul><ul><ul><li>Better lateral throwoff </li></ul></ul><ul><ul><li>Smaller dose to mucosa </li></ul></ul><ul><li>Dose to point A- 8000R </li></ul><ul><li>Dose to uterus wall -30,000R </li></ul><ul><li>Dose to vaginal mucosa-20,000R </li></ul><ul><li>Dose to recto-vaginal septum- 6750 R </li></ul><ul><li>Dose limitation </li></ul><ul><ul><li>BLADDER <80 Gy </li></ul></ul><ul><ul><li>RECTUM <75 Gy </li></ul></ul>
    • 61. INTRACAVITARY APPLICATORS <ul><li>MANCHESTER </li></ul><ul><li>PGI </li></ul>
    • 62. IDEAL APPLICATION <ul><li>Tandem </li></ul><ul><ul><li>1/3 of the way between S1 –S2 and the symphysis pubis </li></ul></ul><ul><ul><li>Midway between the bladder and S1 -S2 </li></ul></ul><ul><ul><li>Bisect the ovoids </li></ul></ul><ul><li>Marker seeds should be placed in the cervix </li></ul><ul><li>Ovoids </li></ul><ul><ul><li>against the cervix (marker seeds) </li></ul></ul><ul><ul><li>Largest </li></ul></ul><ul><ul><li>Separated by 0.5-1.0 mm </li></ul></ul><ul><ul><li>Axis of the tandem-central </li></ul></ul><ul><li>Bladder and rectum - should be packed away from the implant </li></ul>
    • 63. ICRU REPORT NO.38 <ul><li>DOSIMETRIC INFORMATION FOR REPORTING </li></ul><ul><li>Complete description </li></ul><ul><ul><li>Technique </li></ul></ul><ul><ul><li>Time-dose pattern </li></ul></ul><ul><li>Treatment prescription </li></ul><ul><li>Total Reference Air Kerma </li></ul><ul><li>Dose description </li></ul><ul><ul><li>Prescription points/surface </li></ul></ul><ul><ul><li>Reference dose in central plane </li></ul></ul><ul><ul><li>Mean central /peripheral dose </li></ul></ul><ul><li>Volumes: Treated/ point A/ reference volume </li></ul><ul><li>Dose to Organs at Risk : bladder, rectum </li></ul>
    • 64. <ul><li>REFERENCE VOLUME </li></ul><ul><ul><li>Dimensions of the volume included in the corresponding isodose </li></ul></ul><ul><ul><li>The recommended dose 60 Gy </li></ul></ul><ul><li>TREATED VOLUME </li></ul><ul><ul><li>Pear and Banana shape </li></ul></ul><ul><ul><li>Received the dose appropriate to achieve the purpose of the treatment, e.g., tumor eradication or palliation, within the limits of acceptable complications </li></ul></ul><ul><li>IRRADIATED VOLUME </li></ul><ul><ul><li>Volumes surrounding the Treated Volume </li></ul></ul><ul><ul><li>Encompassed by a lower isodose to be specified, e.g., 90 – 50% of the dose defining the Treated Volume </li></ul></ul><ul><ul><li>Reporting irradiated volumes may be useful for interpretation of side effects outside </li></ul></ul>
    • 65. CERVICAL BRACHYTHERAPY
    • 66. ABS.DOSE AT REFERENCE POINTS <ul><li>BLADDER POINT </li></ul><ul><li>RECTAL POINT </li></ul><ul><li>LYMPHATIC TRAPEZOID OF FLETCHER </li></ul><ul><ul><li>LOW PA, LOW COMM.ILIAC LN & MID EXT ILIAC LNs </li></ul></ul><ul><li>PELVIC WALL POINTS </li></ul><ul><ul><li>DISTAL PART OF PARAMETRIUM & OBTURATOR LNs </li></ul></ul>
    • 67. DOSE SCHEDULE <ul><li>LDR (<200cgy/hr) </li></ul><ul><ul><li>35-40 Gy at point A </li></ul></ul><ul><li>MDR (200-1200cgy/hr) </li></ul><ul><ul><li>35 Gy LDR EQUIVALENT at point A </li></ul></ul><ul><li>HDR(>1200cgy/hr) </li></ul><ul><ul><li>9 Gy in 2 # </li></ul></ul><ul><ul><li>6.8Gy in 3# at point A </li></ul></ul>
    • 68. EXTERNAL RT WITH BRACHYTHERAPY <ul><li>Brachytherapy can follow external irradiation </li></ul><ul><ul><li>SIMULTANEOUS </li></ul></ul><ul><ul><ul><li>Stage I - II with very minimal parametriun involvement </li></ul></ul></ul><ul><ul><ul><li>HDR -5 sessions (9gy /#/ 5, 1week apart) </li></ul></ul></ul><ul><ul><ul><li>40 Gy by XRT simultaneously </li></ul></ul></ul><ul><ul><li>SANDWICH </li></ul></ul><ul><ul><ul><li>Stage I-II </li></ul></ul></ul><ul><ul><ul><li>MDR 40 Gy LDR eq.—› XRT 40 Gy —› MDR 35 Gy LDR eq. </li></ul></ul></ul><ul><li>In both above cases a MIDLINE SHIELD is used </li></ul>
    • 69. POST OP/ VAULT BRACHYTHERAPY <ul><li>Vault RT </li></ul><ul><ul><li>No residual disease </li></ul></ul><ul><ul><ul><li>8500 cGy at 5mm from the surface of the vault </li></ul></ul></ul><ul><ul><ul><li>2 sessions 1 week apart </li></ul></ul></ul><ul><ul><li>Residual disease </li></ul></ul><ul><ul><ul><li>CTV of 2 cm given to gross tumor and the prescription of 8500cgy encompassing the whole CTV is made </li></ul></ul></ul><ul><ul><ul><li>2 sessions 1 week apart </li></ul></ul></ul><ul><li>Mostly after XRT </li></ul>
    • 70. POST OP BRACHYTHERAPY <ul><li>CONTRAINDICATIONS </li></ul><ul><ul><li>Vaginal wall involvement ( middle- lower 13) </li></ul></ul><ul><ul><li>Heavy parametrium infiltration </li></ul></ul><ul><ul><li>VVF or VRF </li></ul></ul><ul><ul><li>Inadequate space </li></ul></ul><ul><ul><li>Medical contraindications </li></ul></ul><ul><ul><li>Metastatic disease </li></ul></ul><ul><li>Supplementary radiation 2000 cGy 10# 2 weeks </li></ul>
    • 71. SURFACE MOULDS <ul><li>Radiation is delivered by arranging RA sources over the surface of tumor </li></ul><ul><li>Types </li></ul><ul><ul><li>Planar </li></ul></ul><ul><ul><ul><li>Circular </li></ul></ul></ul><ul><ul><ul><li>Square </li></ul></ul></ul><ul><ul><ul><li>Rectangular </li></ul></ul></ul><ul><ul><li>Line source </li></ul></ul><ul><ul><li>Cylinder </li></ul></ul>
    • 72. INDICATIONS <ul><li>Superficial /Accessible tumors </li></ul><ul><li>Skin ca </li></ul><ul><li>Post mastectomy recurrence </li></ul><ul><li>Oral tumor </li></ul><ul><ul><li>hard palate ,alveolus </li></ul></ul><ul><li>Penile carcinoma </li></ul>
    • 73. CIRCULAR MOULDS <ul><li>Amount of radium used is obtained from the table for a particular treating distance </li></ul><ul><li>Circular arrangement is the best </li></ul><ul><li>Space between the needles (end) should not be more than H </li></ul>
    • 74. SQUARE MOULDS <ul><li>An arrangement is considered to be linear if the distance between the active end of the sources does not exceed the height </li></ul><ul><li>Length of the side of the square is less than twice the height </li></ul><ul><ul><li>No further radium is placed in the center </li></ul></ul>
    • 75. RECTANGULAR MOULDS <ul><li>The dividing lines or bars are placed parallel to the longer side </li></ul><ul><li>Elongation correction factor: Increase the reading in milligrams hour by a given factor </li></ul><ul><ul><li>This factor is proportional to the ratio of the sides of the rectangle </li></ul></ul><ul><ul><ul><li>1.5:1 = 2.5% </li></ul></ul></ul><ul><ul><ul><li>2:1 = 5% </li></ul></ul></ul><ul><ul><ul><li>3:1 = 9% </li></ul></ul></ul><ul><ul><ul><li>4:1 = 12% </li></ul></ul></ul>
    • 76. CIRCULAR MOULDS <ul><li>CURVED SURFACES </li></ul><ul><li>COAXIAL RINGS </li></ul><ul><li>Irregular area </li></ul><ul><li>Curved surfaces: convex, concave </li></ul><ul><ul><li>The smaller area is used for calculation of radium dose and implant rules </li></ul></ul><ul><li>Cylinder mould: Amount of radium is 30D 2 </li></ul><ul><li>DISTRIBUION RULES </li></ul><ul><ul><li>In case of coaxial rings radium is placed at a distance equal to 2H </li></ul></ul>
    • 77. INTRALUMINAL BRACHYTHERAPY <ul><li>Radioactive source is passed through a tube and passed into a hollow lumen </li></ul><ul><li>Sites </li></ul><ul><ul><li>Esophagus </li></ul></ul><ul><ul><li>Bronchus : Bronchogenic carcinoma </li></ul></ul><ul><ul><ul><li>Definitive : T 1 -T 2 tumors </li></ul></ul></ul><ul><ul><ul><li>Palliative </li></ul></ul></ul><ul><ul><ul><ul><li>Dyspnea </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Cough </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Atelectasis </li></ul></ul></ul></ul><ul><ul><li>Biliary tract </li></ul></ul>
    • 78. RADIOBIOLOGY <ul><li>Biological effects depend on </li></ul><ul><ul><li>Dose prescribed </li></ul></ul><ul><ul><li>Treated volume </li></ul></ul><ul><ul><li>Dose rate </li></ul></ul><ul><ul><li>Fractionation </li></ul></ul><ul><ul><li>Treatment duration </li></ul></ul><ul><li>Heterogeneous dose distribution </li></ul><ul><li>Higher average dose </li></ul><ul><li>Short treatment </li></ul>
    • 79. RADIOBIOLOGY – 4 Rs <ul><li>Repair </li></ul><ul><li>Reassortment / redistribution </li></ul><ul><li>Repopulation </li></ul><ul><li>Reoxygenation </li></ul>
    • 80. RADIOBIOLOGY- LDR <ul><li>Repair of Sublethal damage </li></ul><ul><li>Most significant- 1 Gy/min and 0.3 Gy /h </li></ul><ul><li>DNA repair </li></ul><ul><ul><li>Dynamic process </li></ul></ul><ul><ul><li>Special kinetics </li></ul></ul><ul><li>Simple exponential kinetics </li></ul><ul><li>Reassortment - slow and imp. <1 Gy/min </li></ul><ul><li>Repopulation-slowest and significant </li></ul><ul><li>Reoxygenation - relative slow process may be a disadvantage </li></ul>
    • 81. LDR AND HDR <ul><li>LDR vs HDR </li></ul><ul><li>EFFECTS OF HDR </li></ul>
    • 82. RADIOACTIVE SOURCES <ul><li>Naturally occurring </li></ul><ul><li>Artificial </li></ul><ul><li>Induced by neutron bombardment </li></ul><ul><li>Induced by bombardment of protons </li></ul><ul><li>Fission product </li></ul><ul><li>CHARACTERISTICS </li></ul><ul><ul><li>HALF LIFE </li></ul></ul><ul><ul><li>GAMMA ENERGY </li></ul></ul><ul><ul><li>BETA ENERGY </li></ul></ul><ul><ul><li>HALF VALUE LAYER </li></ul></ul><ul><ul><li>EXPOSURE RATE CONSTANT </li></ul></ul><ul><ul><li>BETA FILTRATION </li></ul></ul><ul><ul><li>DECAY SCHEME </li></ul></ul>
    • 83. IDEAL RADIONUCLIDE <ul><li>Photon energy :low to medium- 0.03 to 0.5 MeV </li></ul><ul><ul><li>Monoenergetic beam preferred </li></ul></ul><ul><li>Moderate Gamma ray constant </li></ul><ul><li>Long half life </li></ul><ul><li>High specific activity </li></ul><ul><li>Isotropic </li></ul><ul><li>No gaseous disintegration/daughter product </li></ul><ul><li>Nuclei should not disperse if source damaged </li></ul><ul><li>Low beta energy </li></ul><ul><li>Low or no self attenuation </li></ul><ul><li>Insoluble and nontoxic </li></ul><ul><li>Flexible </li></ul><ul><li>Easily available and cost effective </li></ul><ul><li>Withstand sterilization process </li></ul><ul><li>Disposable without radiation hazards to environment </li></ul>
    • 84. RADIUM 226 <ul><li>Sixth member of the radio active series which starts with uranium and ends with lead </li></ul><ul><li>Half life 1620 years </li></ul><ul><li>Gamma energy 0.83 MeV </li></ul><ul><li>Half value 12mm Pb </li></ul><ul><li>Exposure rate constant 8.25 Rcm 2 /mCi-h </li></ul><ul><li>Filtration 0.5 – 1 mm Pt </li></ul>
    • 85. RADIUM SUBSTITUTES NAME ORIGIN T 1/2 γ ENERGY-MeV β ENERGY β FILTRATION HVL (Pb -mm) ERC SPECI. ACTI. DECAY PRODUCT Rn 222 NATURAL 3.83 days 0.83 Stainless steel 12 10.27 Pb 206 Cs 137 FISSION 30.17 yrs 0.662 0.512 1.17 - do - 6.5 3.26 87 Ba 137 Co 60 NEUTRON ACTIVAT. 5.26 yrs 1.17, 1.33 0.38 - do- 11 13.07 1020 Ni 60 Ir 192 - do - 73.8 yrs 0.136- 1.06 0.079-0.068 Platinum 4 4.69 7760 Pt 192 Tn 182 - do - 115 yrs 0.67 - Platinum 12 6.87 - - Au 198 - do - 2.7 days 1.088- 0.412 0.96 St. steel 3.3 2.376 - Hg 198 I 125 - do - 59.4 days 0.274, 0.314 No Titanium 0.01 10th 1.403 - Te 125 Pd 103 - do - 16.97 days 0.21 No Platinum 0.03 6.87 - Ru 103
    • 86. Thank You

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