multiple filed arrangement in Radiotherapy, Medical College Kolkata
•Als PPT, PDF herunterladen•
23 gefällt mir•5,309 views
![[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
Empfohlen
Empfohlen
Weitere ähnliche Inhalte
Was ist angesagt?
Was ist angesagt? (20)
Andere mochten auch
Andere mochten auch (20)
Ähnlich wie multiple filed arrangement in Radiotherapy, Medical College Kolkata
Ähnlich wie multiple filed arrangement in Radiotherapy, Medical College Kolkata (20)
Kürzlich hochgeladen
Kürzlich hochgeladen (20)
multiple filed arrangement in Radiotherapy, Medical College Kolkata
- 1. Dose distribution in matter: Multiple and wedge field technique Dr. Dipanjan Majumder MD PGT Dept. of radiotherapy Medical college,kolkata
- 7. Co- 60 4-6 MV beam thickness 15 cm dose uniform if 20 cm 10 MV or higher energy needed.
- 10. Unit of intgral dose is gram-rad or kilogram-gray Or simply joule. 1000 rad delivered at midpoint of a 25 cm thick pt. Field size 10 cm d ; SSD = 100 cm.
- 15. Isocentric technique: Point of intersection of collimator axis and gantry axis - isocenter Stationary beam: Isocenter placed within patient beams directed from different direction. SSD=SAD-d if SSD SAD isocentric method can be used Advantage: setup accuracy Machine isocentricity dependence rather skin marks
- 17. Calculations: D iso = D o ×S c ×S p ×TMR Diso=dose rate at isocenter Do=Dmax dose rate for 10,10 field at the SAD Sc=collimator scater factor Sp=phantom scater factor.(for given field size at isocenter) TMR=average TMR over all deapths.
- 21. HOW TO TREAT SUPERFICIAL TUMOR BY MULTIPLE FIELDS?
- 26. Separation of adjacent fields
- 28. Lance & Morgan angled beam technique.
- 30. Field separation methods : Geometric: Two adjacent beams are considered.joined at given depth d. L1&L2 be the lengths, SSD1&SSD2 are source to surface distance.then S=S1+S2=½.L1.d/SSD1+½.L2.d/SSD2
- 31. WHAT THE PROBLEM IN JUCTIONAL REGION: THREE FIELD OVERLAP
- 33. Calculations: Three-field overlap dS=S1-S2 dS=0 then L1/L2=SSD1/SSD2 If field sizes different SSD s to be adjusted accordingly. If S1+S2 increased by dS three field overlap eliminated but cold spot at mid line. Practically dS* used; dS*=dS.[(d*-d)/d] d* =distance of critical organ from surface ; d= midline distance
- 34. Dosimetric: Separation of the fields can be determined by optimizing placement of the fields on contour so that composite isodose uniform. Hot and cold spots are acceptable .
- 36. S=½.L.d/SSD
- 37. CSI field matching technique:
- 39. θ coll =arc tan(½.L 1 .1/SSD) Θ couch =arc tan(½.L 2 .1/SAD) L1=length of posterior spinal field. L2=length of lateral cranial field SSD=for spinal field SAD=for cranial field
- 41. Thank youss Thank you