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<ul><li>DR. MANOJ KUMAR B  </li></ul><ul><li>MODERATOR:PROF. S.C. SHARMA </li></ul><ul><li>DEPTT. OF RADIOTHERAPY AND ONCO...
BRACHYTHERAPY  <ul><li>Type of radiation treatment in which radioactive sources are arranged in such a fashion that radiat...
CLINICAL ADVANTAGES <ul><li>High biological efficacy  </li></ul><ul><li>Rapid dose fall-off  </li></ul><ul><li>High tolera...
LIMITATIONS & DISADVANTAGES <ul><li>Difficult for inaccessible regions  </li></ul><ul><li>Limited for small tumors (T 1 _T...
SELECTION CRITERIA <ul><li>Easily accessible lesions </li></ul><ul><li>Early stage diseases (Ideal implant  ≤ 5 cm) </li><...
INDICATIONS <ul><li>RADICAL  RADIATION  </li></ul><ul><ul><li>Skin malignancies- BCC, SCC </li></ul></ul><ul><ul><li>Head ...
INDICATIONS... <ul><li>PERIOPERTIVE </li></ul><ul><ul><li>STS </li></ul></ul><ul><ul><li>Ca Breast </li></ul></ul><ul><li>...
CLASSIFICATION Classification Schemes Positioning of Radionuclide Dose rate of irradiation Duration of irradiation Loading...
CLASSIFICATION <ul><li>SURGICAL APPROACH / POSITIONING  </li></ul><ul><ul><li>SOURCE IN TUMOR </li></ul></ul><ul><ul><ul><...
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 confinemen...
ADVANTAGES <ul><li>LDR </li></ul><ul><li>HDR </li></ul><ul><li>Predictable clinical effects </li></ul><ul><li>Superior rad...
MDR BRACHYTHERAPY <ul><li>ADVANTAGES </li></ul><ul><ul><li>Comparative shorter T/T time </li></ul></ul><ul><ul><li>One tim...
SOURCE LOADING TECHNIQUE <ul><li>PRELOADING  SYSTEM </li></ul><ul><ul><li>Live sources </li></ul></ul><ul><ul><li>ADVANTAG...
AFTER LOADING TECHNIQUE <ul><li>MANUAL </li></ul><ul><ul><li>Avoids radiation protection issue of preloading </li></ul></u...
INTERSTITIAL BRACHYTHERAPY <ul><li>Sealed Radioactive sources directly implanted into the tumor in a geometric fashion </l...
INTERSTITIAL BRACHYTHERAPY… <ul><li>DISADVANTAGES </li></ul><ul><ul><li>Radiation hazards in older days </li></ul></ul><ul...
SELECTION CRITERIA <ul><li>Easily accessible lesions, at least from one side </li></ul><ul><li>Early stage disease </li></...
CLINICAL APPLICATIONS <ul><li>Head & neck tumors </li></ul><ul><ul><li>Early stage oropharyngeal cancers </li></ul></ul><u...
TYPES OF INTERSTITIAL IMPLANTS ACCORDING TO SIZE/LOCATION/PROXIMITY OF TUMOR TO NORMAL STRUCTURES <ul><li>TEMPORARY </li><...
SYSTEMS OF IMPLANT DOSIMETRY <ul><li>OBJECTIVES OF TREATMENT PLANNING </li></ul><ul><ul><li>To determine the distribution ...
SYSTEMS OF IMPLANT DOSIMETRY <ul><li>These system designed during times when computers were not available for routine plan...
RULES OF INT.IMPLANT SYSTEM PARAMETERS MANCHESTER QUIMBY PARIS COMPUTER Linear strength Variable Constant Constant Constan...
COMPONENTS-CLASSICAL SYSTEM <ul><li>DISTRIBUTION RULES :  given a target volume, distribution rules determine how to distr...
PRINCIPLE-MANCHESTER SYSTEM FEATURES DOSE  &  DOSE RATE  6000-8000 R in 6-8 days (1000 R/day; 40 R/hr) UNIT / USE OF RADIU...
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>Eq...
PARIS SYSTEM- PRINCIPLES <ul><li>RADIOACTVE SOURCES </li></ul><ul><li>Rectilinear/parallel -arrangement so that centers ar...
PARIS SYSTEM FEATURES DOSE AND DOSE RATE 6000 -7000 cGy  in 3-11 days DOSE PRESCRIPTION POINT Average of the minimum doses...
PERMANENT IMPLANTS <ul><li>ADVANTAGES  </li></ul><ul><li>DISADVANTAGES </li></ul><ul><ul><li>Less accessible sites </li></...
COMPUTER SYSTEM <ul><li>Implant system evolved through use of computers </li></ul><ul><li>Implantation rules: Sources of u...
COMPUTER DOSIMETRY <ul><li>Possible to preplan implants & complete isodose distribution corresponding to final source dist...
COMPUTER DOSIMTERY <ul><li>Dose Computation: </li></ul><ul><ul><li>Dose calculation Formalisms’ (AAPM TG 43 algorithm) </l...
CLINICAL APPLICATIONS <ul><li>Oral Cavity: </li></ul><ul><li>LIP: </li></ul><ul><ul><li>Indications:  T1-2N0 Lesions  </li...
CLINICAL APPLICATIONS… <ul><li>Buccal Mucosa: </li></ul><ul><ul><li>Indications:   </li></ul></ul><ul><ul><ul><li>Brachyth...
CLINICAL APPLICATIONS… <ul><li>Oral Tongue: </li></ul><ul><li>Indications:  T1 N0, T2 N0 < 3cm lesion </li></ul><ul><li>T....
CLINICAL APPLICATIONS… <ul><li>Floor of Mouth : </li></ul><ul><ul><li>Indications:  T1-2N0 lesions,  ≥ 5 mm away from mand...
CLINICAL APPLICATIONS… <ul><li>Breast </li></ul><ul><ul><li>Indications: Boost after BCS & EBRT </li></ul></ul><ul><ul><ul...
CLINICAL APPLICATIONS… <ul><li>T.V.:  Primary Tumor site + 2-3 cm margin </li></ul><ul><li>Dose:  As Boost: 10-20 Gy LDR <...
CLINICAL APPLICATIONS…
CLINICAL APPLICATIONS… <ul><li>Prostate: </li></ul><ul><li>Indications </li></ul><ul><ul><li>Brachytherapy as monotherapy:...
CLINICAL APPLICATIONS… <ul><li>Technique for Permanent implant </li></ul><ul><li>Retropubic approach with  I 125  seeds- D...
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...
CLINICAL APPLICATIONS <ul><li>Soft tissue Sarcomas  (using Ir 192  or I 125 ) </li></ul><ul><li>Indications: </li></ul><ul...
CLINICAL APPLICATIONS… <ul><li>Technique: </li></ul><ul><ul><li>Usually performed at time of surgery </li></ul></ul><ul><u...
<ul><li>Brain:  Permanent or temporary (using I 125  or   Ir 192  seeds/wires   ) </li></ul><ul><li>Indications:   </li></...
CLINICAL APPLICATIONS… <ul><li>Ca Anorectum </li></ul><ul><li>Indications:  As boost to EBRT/ChemoRT </li></ul><ul><ul><ul...
CLINICAL APPLICATIONS… <ul><li>Gynecological Tumors  ( Ir 192  LDR or HDR) </li></ul><ul><li>Indications: </li></ul><ul><u...
CLINICAL APPLICATION – CA CX <ul><ul><ul><li>  ABS Recommendations </li></ul></ul></ul><ul><ul><ul><li>Bulky primary disea...
CLINICAL APPLICATIONS… <ul><ul><li>PERINEAL IMPLANTS </li></ul></ul>Martinez Universal Perineal Interstitial Template (MUP...
CLINICAL APPLICATIONS… <ul><li>Dose: </li></ul><ul><ul><li>Radical BT: </li></ul></ul><ul><ul><ul><li>LDR: 55-60 Gy @ 50-9...
CLINICAL APPLICATIONS… <ul><li>Other sites: </li></ul><ul><ul><li>Lung:  Permanent perioperative BT, I 125  seeds, Au 198 ...
INTRACAVITARY APPLICATION <ul><li>Radioactive sources are placed in a existing cavity usually inside a predefined applicat...
PARIS SYSTEM <ul><li>Single application of radium </li></ul><ul><li>Two cork colpostats (cylinder) and an intrauterine tub...
STOCKHOLM SYSTEM <ul><li>Fractionated course of radiation delivered over a period of one month.  </li></ul><ul><li>Usually...
DRAWBACKS OF PARIS AND STOCKHOLM SYSTEMS <ul><li>Long treatment time </li></ul><ul><li>Discomfort to the patient </li></ul...
MANCHESTER SYSTEM <ul><li>To  define  the treatment in terms of dose to a point. Criteria of the point:  </li></ul><ul><ul...
POINT   A <ul><li>PARACERVICAL TRIANGLE  where initial lesion of radiation necrosis occurs </li></ul><ul><li>Area in the m...
 
LOADING OF APPLICATORS <ul><li>In order that point A receives same dosage rate no matter which ovoid combination is used ,...
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 ME...
GUIDELINES <ul><li>Largest possible ovoid </li></ul><ul><ul><li>Lesser  dose to mucosa  </li></ul></ul><ul><li>Longest  po...
INTRACAVITARY APPLICATORS <ul><li>MANCHESTER  </li></ul><ul><li>PGI </li></ul>
IDEAL APPLICATION <ul><li>Tandem  </li></ul><ul><ul><li>1/3 of the way between S1 –S2 and the symphysis pubis </li></ul></...
ICRU REPORT NO.38 <ul><li>DOSIMETRIC INFORMATION FOR REPORTING </li></ul><ul><li>Complete description  </li></ul><ul><ul><...
<ul><li>REFERENCE VOLUME  </li></ul><ul><ul><li>Dimensions of the volume included in the corresponding isodose  </li></ul>...
CERVICAL BRACHYTHERAPY
ABS.DOSE AT REFERENCE POINTS <ul><li>BLADDER POINT </li></ul><ul><li>RECTAL POINT </li></ul><ul><li>LYMPHATIC TRAPEZOID OF...
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/h...
EXTERNAL RT WITH BRACHYTHERAPY <ul><li>Brachytherapy can follow external irradiation </li></ul><ul><ul><li>SIMULTANEOUS </...
POST OP/ VAULT BRACHYTHERAPY  <ul><li>Vault RT </li></ul><ul><ul><li>No residual disease </li></ul></ul><ul><ul><ul><li>85...
POST OP BRACHYTHERAPY <ul><li>CONTRAINDICATIONS </li></ul><ul><ul><li>Vaginal wall involvement ( middle- lower 13) </li></...
SURFACE MOULDS  <ul><li>Radiation is delivered by arranging RA sources over the surface of tumor </li></ul><ul><li>Types  ...
INDICATIONS <ul><li>Superficial /Accessible tumors </li></ul><ul><li>Skin ca </li></ul><ul><li>Post mastectomy recurrence ...
CIRCULAR MOULDS  <ul><li>Amount of radium used is obtained from the table for a particular treating distance </li></ul><ul...
SQUARE MOULDS <ul><li>An arrangement is considered to be linear if the distance between the active end of the sources does...
RECTANGULAR MOULDS <ul><li>The dividing lines or bars are placed parallel to the longer side  </li></ul><ul><li>Elongation...
CIRCULAR MOULDS <ul><li>CURVED SURFACES </li></ul><ul><li>COAXIAL RINGS </li></ul><ul><li>Irregular area </li></ul><ul><li...
INTRALUMINAL BRACHYTHERAPY <ul><li>Radioactive source is passed through a tube and passed into a hollow lumen </li></ul><u...
RADIOBIOLOGY <ul><li>Biological effects  depend on </li></ul><ul><ul><li>Dose prescribed  </li></ul></ul><ul><ul><li>Treat...
RADIOBIOLOGY – 4 Rs <ul><li>Repair </li></ul><ul><li>Reassortment / redistribution  </li></ul><ul><li>Repopulation </li></...
RADIOBIOLOGY- LDR <ul><li>Repair of Sublethal damage  </li></ul><ul><li>Most significant- 1 Gy/min and 0.3 Gy /h </li></ul...
LDR AND HDR <ul><li>LDR vs HDR </li></ul><ul><li>EFFECTS OF HDR  </li></ul>
RADIOACTIVE SOURCES <ul><li>Naturally occurring </li></ul><ul><li>Artificial </li></ul><ul><li>Induced by neutron bombardm...
IDEAL RADIONUCLIDE <ul><li>Photon energy :low to medium- 0.03 to 0.5 MeV </li></ul><ul><ul><li>Monoenergetic  beam preferr...
RADIUM 226 <ul><li>Sixth member of the radio active series which starts with uranium and ends with lead </li></ul><ul><li>...
RADIUM SUBSTITUTES NAME ORIGIN T 1/2 γ ENERGY-MeV β  ENERGY β  FILTRATION HVL (Pb -mm) ERC SPECI. ACTI. DECAY PRODUCT Rn 2...
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Brachytherapy Final

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  • Transcript of "Brachytherapy Final"

    1. 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. 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. 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. 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. 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. 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. 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. 8. CLASSIFICATION Classification Schemes Positioning of Radionuclide Dose rate of irradiation Duration of irradiation Loading pattern
    9. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 38. CLINICAL APPLICATIONS…
    39. 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. 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. 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. 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. 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. 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. 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. 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. 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. 48. CLINICAL APPLICATIONS… <ul><ul><li>PERINEAL IMPLANTS </li></ul></ul>Martinez Universal Perineal Interstitial Template (MUPIT ) Syed-Neblett template
    49. 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. 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. 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. 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. 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. 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. 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. 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>
    58. 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
    59. 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>
    60. 61. INTRACAVITARY APPLICATORS <ul><li>MANCHESTER </li></ul><ul><li>PGI </li></ul>
    61. 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>
    62. 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>
    63. 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>
    64. 65. CERVICAL BRACHYTHERAPY
    65. 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>
    66. 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>
    67. 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>
    68. 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>
    69. 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>
    70. 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>
    71. 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>
    72. 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>
    73. 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>
    74. 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>
    75. 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>
    76. 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>
    77. 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>
    78. 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>
    79. 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>
    80. 81. LDR AND HDR <ul><li>LDR vs HDR </li></ul><ul><li>EFFECTS OF HDR </li></ul>
    81. 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>
    82. 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>
    83. 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>
    84. 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
    85. 86. Thank You
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