SBRT Treatment Planning: Practical Considerations

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SBRT planning principles are very similar to Cranial SRS planning principles • Inhomogeneous Dose inside PTV • Sharp Dose Fall Off outside PTV • Multiple non-coplanar beams or arcs are needed to create conformal dose distributions. Much more limited non-coplanar beam clearance compared with cranial SRS for LINAC based SBRT.
Requirements of SBRT Plan (from RTOG 0813 and 0915 lung protocols) • Maximum Dose: normalized to 100%, must be within PTV • Prescription Isodose: must be ≥ 60% and < 90% of the maximum dose • Prescription Isodose Surface Coverage: 95% of the target volume (PTV) is conformally covered by the prescription isodose surface (PTV V100%PD = 95%) and 99% of the target volume (PTV) receives a minimum of 90% of the prescription dose (PTV V90%PD > 99%) • High Dose Spillage: The cumulative volume of all tissue outside the PTV receiving a dose > 105% of prescription dose should be no more than 15% of the PTV volume • Intermediate Dose Spillage: The falloff gradient beyond the PTV extending into normal tissue structures must be rapid in all directions and meet the criteria in Table1 • Meet the constraints of dose limiting organs at risk
Page 1 and 2: SBRT Treatment Planning: Practical
Page 3 and 4: Outlines • The Basic Principles o
Page 5 and 6: Montefiore-Einstein SBRT Experience
Page 7 and 8: RTOG SBRT Protocols • 0631 Spine
Page 9 and 10: If beam margin is close to beam pen
Page 11 and 12: For single isocenter dose distribut
Page 13 and 14: Conventional SBRT (Ablative intent)
Page 15: For SBRT plans Prescription Isodose
Page 19 and 20: The published protocols usually do
Page 21 and 22: 10cm Conventional Cord 10cm RTOG 06
Page 23 and 24: For Spine Cases: IMRT or VMAT is re
Page 25 and 26: Cord: Max point dose 9.33 Gy V100%
Page 27 and 28: Prescription Isodose Surface Covera
Page 29 and 30: Conformality : Prescription Dose Vo
Page 31 and 32: COR CAX SAG No need to do any non-c
Page 33 and 34: Single Arc Collimator 45 CAX Two Ar
Page 35 and 36: Additional 15 cc volume of normal t
Page 37 and 38: Fixed IMRT Fields 100% PD and above
Page 39 and 40: 9 Field IMRT: Cord Dose DVH 10 Gy 0
Page 41 and 42: Arc2: Couch 15, Gantry 330-110 Arc1
Page 43 and 44: Prescription Isodose Surface Covera
Page 45 and 46: High Dose Spillage PD = 100% = 20 G
Page 47 and 48: Intermediate Dose Spillage: R 50% a
Page 49 and 50: 12.5% isodose restricted mainly in
Page 51 and 52: Liver Montefiore-Einstein Cancer Ce
Page 53 and 54: Hepatocellular Carcinoma Five Fract
Page 55 and 56: SBRT CT simulation • For upper th
Page 57 and 58: SBRT T-Spine • CT scan has to eit
Page 59 and 60: SBRT Lung/Liver/Abdominal Cases •
Page 61 and 62: SBRT Lung/Liver/Abdominal Cases •
Page 63 and 64: GTV is 5mm too inferior (MLC acts a
Page 65 and 66: What is a ‘Dry Run’? • Treatm
Page 67 and 68:
Acknowledgements • Physics Jin Sh
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SBRT Treatment Planning: Practical Considerations

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