Iort

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  • New
  • Added longer of life of 5 years
  • New
  • Said that ITV is not necessary
  • Added a zoom in
  • Added sponsors
  • Covered up the patient’s name
  • Covered up the patient’s name
  • New
  • New
  • Added definition to DSC
  • Compared it to the old ICRU and changed slightly the Low gradient case definition
  • Added sponsors
  • New
  • Iort

    1. 1. Precision in Radiation Oncology: what are the standards and how could it apply to IORT Vincent GREGOIRE, MD, PhD, hon. FRCP Radiation Oncology Dept., & Center for Molecular Imaging and Experimental Radiotherapy, Université Catholique de Louvain, St-Luc University Hospital, Brussels, Belgium
    2. 2. Bataini et al, 1982 , 4 5 5 5 6 5 7 5 8 5 9 5 T o t a l d o s e ( G y ) 0 2 0 4 0 6 0 8 0 1 0 0 1 2 0 Tumor control (%) Dose-response curve for neck nodes ≤ 3 cm Tumor Control Probability (TCP)
    3. 3.  Human  Monkey Baumann et al., Strahlenther Onkol 170: 131-139, 1994 Normal Tissue Control Probability (NTCP)
    4. 4. Target J. John, 1974
    5. 5. ICRU report 62, 1999 <ul><li>Gross Tumor Volume: GTV </li></ul><ul><li>Clinical Target Volume: CTV </li></ul><ul><li>Internal Target Volume: ITV </li></ul><ul><li>Planning Target Volume: PTV </li></ul><ul><li>Organ at Risk: OAR </li></ul><ul><li>Planning Organ at Risk Volume: PRV </li></ul>Target volumes in Radiation Oncology: ICRU 50 and 62:
    6. 6. Target volumes in EBRT Before Rx-CH 46 Gy (Rx-CH) Right piriform sinus (ICDO-10: C12.9) SCC grade 2 TNM 6 th ed: T4N0M0 Fiberoptic examination CT MRI T2 FS FDG-PET
    7. 7. <ul><li>The Clinical Target Volume (CTV) is a volume of tissue that contains a demonstrable GTV and/or subclinical malignant disease at a certain probability considered relevant for therapy…, </li></ul><ul><li>The CTV is thus an anatomical-clinical concept. </li></ul>Clinical Target Volume (CTV) ICRU IMRT report Target volumes in EBRT
    8. 8. Clinical Target Volume (CTV) Target volumes in EBRT
    9. 9. Mesorectal subsite Lymph node regions Posterior PS Selection and delineation of Target Volume Haustermans et al., 2005
    10. 10. The Planning Target Volume is a geometrical concept, introduced for treatment planning and evaluation. It is the recommended tool to shape dose distributions that ensure with a clinically acceptable probability that an adequate dose will actually be delivered to all parts of the CTV… Planning Target Volume (PTV) ICRU IMRT report Target volumes in EBRT
    11. 11. CTV 2 = GTV 2 ICRU IMRT report Target volumes in EBRT PTV 1 : dose 1 CTV 1 GTV 1 (pre-RxTh CT+ iv contrast) PTV 2 : dose 2 GTV 2 (FDG-PET @ 46 Gy)
    12. 12. Target volumes in IORT + EBRT CTV 1 = “tumor bed” PTV 1 = PTV 1 : dose 1 IORT PTV 2 : dose 2 CTV 2 (clinical knowledge) EBRT
    13. 13. Normal tissues in EBRT <ul><li>Distinction between “serial-like” (e.g. spinal cord) and “parallel-like organs” (e.g. parotid gland), </li></ul><ul><li>For “tubed” organs (e.g. rectum) wall delineation, </li></ul><ul><li>Remaining Volume at Risk (RVR): optimization and late effects (e.g. carcinogenesis). </li></ul>Organ At Risk (OAR) and Remaining Volume at Risk (RVR) ICRU IMRT report
    14. 14. <ul><li>PRV is a geometrical concept (tool) introduced to ensure that adequate sparing of OAR will actually be achieved with a reasonable probability , </li></ul><ul><li>A positive OAR to PRV margin for serial organ. </li></ul><ul><li>Dose-volume constraints on OAR are with respect to the PRV, </li></ul><ul><li>Priority rules when overlapping PTVs or PTV-PRV(OAR), </li></ul><ul><li>Dose is reported to the PRV. </li></ul>Planning Organ at Risk Volume (PRV) ICRU IMRT report Normal tissues in EBRT
    15. 15. IORT and Target Volumes <ul><li>GTV is typically absent </li></ul><ul><li>Clinical definition of the CTV: “the operative bed”… </li></ul><ul><li>PTV = CTV </li></ul><ul><li>OAR = PRV are less clearly individualized </li></ul>ICRU report 71, 2004
    16. 16. The Human Condition. R. Magritte, 1935
    17. 17. Absorbed dose in EBRT <ul><li>Planning aims: </li></ul><ul><ul><li>PTV 1 : dose x , D-V constraints, …, </li></ul></ul><ul><ul><li>Spinal cord: D max = x Gy, …, </li></ul></ul><ul><ul><li>… </li></ul></ul><ul><li>Prescription: </li></ul><ul><ul><li>Physician’s responsibility, </li></ul></ul><ul><ul><li>Acceptance of doses, fraction #, OTT, D-V constraints, beam number, beam orientation, … </li></ul></ul><ul><li>Treatment delivery: </li></ul><ul><ul><li>Instruction file sent to the linac and/or RVS. </li></ul></ul>Dose prescription in 3D-CRT and IMRT ICRU IMRT report
    18. 18. <ul><li>Level 1: not adequate for 3D-CRT – IMRT, </li></ul><ul><li>Level 2: standard level for dose reporting, </li></ul><ul><li>Level 3: homogeneity, conformity and biological metrics (TCP, NTCP, EUD, …) and confidence intervals. </li></ul>Dose recording in 3D-CRT and IMRT Level of reporting Absorbed dose in EBRT ICRU IMRT report
    19. 19. ICRU Reference Point Not A “Typical Point” for IMRT Segments 4-7, 9-13 13 segment IM Field From Jatinder Palta, University of Florida Absorbed dose in EBRT Segment 1 Segment 2 Segment 3 Segment 8
    20. 20. <ul><li>Dose-volume reporting: </li></ul><ul><ul><li>D v : i.e. D 50 (D median ), D 95 </li></ul></ul><ul><ul><li>D mean </li></ul></ul><ul><ul><li>Near minimum dose: D 98 </li></ul></ul><ul><ul><li>Near maximum dose: D 2 </li></ul></ul><ul><li>State the make, model and version number of the treatment planning and delivery software used to produce the plans and deliver the treatment. </li></ul>Metrics for level 2 reporting of PTV Absorbed dose in EBRT ICRU IMRT report
    21. 21. <ul><li>“ Serial-like” organs: </li></ul><ul><ul><li>D near-max (D 98 ). </li></ul></ul><ul><li>“ Parallel-like” organs: </li></ul><ul><ul><li>D mean (e.g. parotid) , </li></ul></ul><ul><ul><li>V d where d refers to dose in Gy (e.g. V 20 for lung). </li></ul></ul>Metrics for level 2 reporting of PRV Absorbed dose in EBRT ICRU IMRT report
    22. 22. Homogeneity and Conformity Low Homogenenity – High Conformity High Homogeneity – Low Conformity Dose Dose Dose Dose Vol Vol Vol Vol Absorbed dose in EBRT ICRU IMRT report Vol Dose Vol Dose Vol Dose Vol Dose High Homogeneity – High Conformity Low Homogeneity – Low Conformity
    23. 23. IORT and dose prescription, reporting and recording <ul><li>Level 1 (2-D) dose prescription, reporting and recording… </li></ul><ul><li>Dose prescription at 90% isodose for electron beams </li></ul><ul><li>Reporting of ICRU reference point dose, and best estimate of D min and D max </li></ul><ul><li>Recording as for EBRT </li></ul>ICRU report 71, 2004
    24. 24. <ul><li>Recommendations for common understanding and proper prescription and reporting especially in combined treatment, e.g. IORT followed by EBRT </li></ul><ul><li>Less sophisticated prescription and reporting for IORT </li></ul><ul><li>Volumetric prescription and reporting…? </li></ul>Conclusions
    25. 25. Conclusions <ul><li>ICRU recommendations still needed even for 3D-CRT and IMRT to avoid unwanted treatment heterogeneity, </li></ul><ul><li>New report based on ICRU foundations, e.g. volumes, </li></ul><ul><li>Adjustments and modifications performed when necessary, e.g. dose-volume reporting, </li></ul><ul><li>Final draft ready for early 2007 / publication in early 2008 </li></ul>ICRU report on 3D-CRT and IMRT
    26. 26. Recording in 3D-CRT and IMRT <ul><li>Electronic archiving for at least the life of patient or 5 years – whatever is longer, </li></ul><ul><li>Complete reconstruction of the treatment plan and delivery record, </li></ul><ul><li>For clinical trials, longer archiving if scientifically justified. </li></ul>Absorbed dose in EBRT ICRU IMRT report
    27. 27. <ul><li>Sometimes the largest component of the margin between the GTV and CTV will be the delineation error in drawing the GTV, </li></ul><ul><li>Consideration should be made for this in the clinical margin. </li></ul>Clinical Target Volume (CTV) Target volumes in Radiation Oncology
    28. 28. Planning Target Volume (PTV) Target volumes in Radiation Oncology <ul><li>Include both “internal” and “external” variations of the CTV, </li></ul><ul><li>Separate delineation of the ITV may not be necessary, </li></ul><ul><li>Expansion of the CTV using “rolling ball” algorithms, </li></ul><ul><li>CTV to PTV margin recipe based on random and systematic errors, </li></ul><ul><li>Priority rules when overlapping PTVs or PTV-PRV, </li></ul><ul><li>Dose is prescribed and reported on the PTV. </li></ul>
    29. 29. CTV to PTV margin recipe Target volumes in Radiation Oncology Van Herk, 2003
    30. 30. Effect Dose Uncomplicated tumor control: Therapeutic Ratio Unacceptable normal tissue damage Tumour control Uncomplicated tumour control
    31. 31. ICRU committee on volume and dose specification for prescribing, reporting and recording special techniques in external photon beam therapy: conformal and IMRT. Vincent GREGOIRE, M.D., Ph.D. and Thomas R. MACKIE, Ph.D.* Radiation Oncology Dept., & Center for Molecular Imaging and Experimental Radiotherapy, Université Catholique de Louvain, St-Luc University Hospital, Brussels, Belgium and * Dept. of Medical Physics, University of Wisconsin, Madison, WI, USA.
    32. 32. The stone of Rosette (Champolion)
    33. 33. The need for an new ICRU report on 3D-CRT and IMRT <ul><li>Biological Target Volume (BTV): C. Ling, IJROBP 2000, </li></ul><ul><li>Hypoxic TV (HTV), Proliferation TV (PTV), …: ESTRO physics meeting, 2003, </li></ul><ul><li>working PTV (wPTV): Ciernik IF, IJROBP, 2005, </li></ul><ul><li>AAPM 2005: “… with the use of IMRT, ICRU recommendations will not be needed anymore…”. </li></ul>It was published and/or mentioned …
    34. 34. ICRU committee for 3D-CRT and IMRT <ul><li>Sponsors </li></ul><ul><ul><li>Andr é Wambersie MD, PhD, Brussels, Belgium </li></ul></ul><ul><ul><li>Paul DeLuca PhD, Madison, USA </li></ul></ul><ul><ul><li>Reinhard Gahbauer MD, Ph.D, Columbus, USA </li></ul></ul><ul><ul><li>Gordon Whitmore Ph.D, Toronto, Canada </li></ul></ul><ul><li>Chairmen </li></ul><ul><ul><li>Vincent Grégoire MD PhD, Brussels, Belgium </li></ul></ul><ul><ul><li>T. Rock Mackie PhD, Madison, USA </li></ul></ul><ul><li>Members </li></ul><ul><ul><li>Wilfried De Neve MD PhD, Gent, Belgium </li></ul></ul><ul><ul><li>Mary Gospodarowicz MD, Toronto, Canada </li></ul></ul><ul><ul><li>Andrzej Niemierko PhD, Boston, USA </li></ul></ul><ul><ul><li>James A. Purdy PhD, Sacramento, USA </li></ul></ul><ul><ul><li>Marcel van Herk PhD, Amsterdam, The Netherlands </li></ul></ul><ul><li>Consultants </li></ul><ul><ul><li>Anders Ahnesjö PhD, Uppsala, Sweden </li></ul></ul><ul><ul><li>Michael Goiten PhD, Windisch, Switzerland </li></ul></ul><ul><ul><li>Nilendu Gupta PhD, Colombus, USA </li></ul></ul>
    35. 35. ICRU report 62, 1999 Target volumes in Radiation Oncology Unresolved issues for 3D-CRT and IMRT <ul><li>Multiple GTV, e.g. anatomic vs functional imaging; before and during treatment, …, </li></ul><ul><li>GTV to CTV margins: clinical probability, </li></ul><ul><li>CTV to PTV margins: geometric probability; overlapping volumes, </li></ul><ul><li>ITV ??? </li></ul><ul><li>OAR: open vs closed volume? Remaining normal tissues? </li></ul><ul><li>PRV: serial vs parallel OAR. </li></ul>
    36. 36. Organ At Risk (OAR) PTV Rectal wall Rectum ICRU IMRT report Normal tissues in EBRT
    37. 37. Parotid sparing with IMRT ICRU IMRT report Normal tissues in EBRT Superficial lobe Superficial and deep lobe
    38. 38. “ Cheating on the PTV margins” <ul><li>The practice of shrinking the CTV to PTV margin to accommodate an OAR is discouraged as it results in a deceptively better PTV homogeneity, </li></ul><ul><li>In IMRT the trade-off can be accomplished by changing the planning aims in the optimizer, </li></ul><ul><li>In 3-D CRT, the trade-off can be accomplished with a separate target delineation used to draw the beam boundary. </li></ul>ICRU IMRT report Target volumes in EBRT
    39. 39. ICRU report 62, 1999 Absorbed dose in Radiation Oncology: ICRU 50 and 62: <ul><li>Dose prescription: </li></ul><ul><ul><li>Responsibility of the treating physician. </li></ul></ul><ul><li>Dose reporting: </li></ul><ul><ul><li>ICRU reference point, </li></ul></ul><ul><ul><li>Three-levels of dose reporting, </li></ul></ul><ul><ul><li>Point-doses: D ICRU point , D min , D max , … </li></ul></ul><ul><li>Dose recording. </li></ul>
    40. 40. ICRU report 62, 1999 Absorbed dose in Radiation Oncology: Unresolved issues for 3D-CRT and IMRT <ul><li>Discrepancy between dose-volume constraint prescription and dose delivery, </li></ul><ul><li>Single point dose prescription, </li></ul><ul><li>Single point dose reporting, </li></ul><ul><li>Biological metrics (e.g. EUD, TCP, NTCP, …), </li></ul><ul><li>Uncertainties in dose reporting, </li></ul><ul><li>Quality assurance. </li></ul>
    41. 41. Dose-Volume Reporting D 95 D 2 0 10 20 30 40 50 60 70 80 90 100 50 55 60 65 70 Dose (Gy) Percent Volume D98=60Gy D50=60Gy D v with v≠50 may require a change in prescription value D 98 D 50 is close to ICRU Reference Dose at a Point Absorbed dose in EBRT
    42. 42. <ul><li>Homogeneity: </li></ul><ul><ul><li>- Standard deviation in dose to the PTV. </li></ul></ul><ul><li>Conformity: </li></ul><ul><ul><li>- Conformity Index: CI = TV/PTV, </li></ul></ul><ul><ul><li>Dice Similarity Coefficient (DSC): </li></ul></ul><ul><ul><li>DSC = TV  PTV / TV  PTV  </li></ul></ul>Examples of metrics for level 3 reporting of PTV Absorbed dose in EBRT
    43. 43. QA in 3D-CRT and IMRT <ul><li>Appropriate QA of TPS and equipments, </li></ul><ul><li>Patient QA not limited to single-point dose check, </li></ul><ul><li>Phantom QA using measured dose and not limited to a single measurement point. </li></ul><ul><li>Independent dose calculation algorithms with similar or better dose calculation accuracy. </li></ul>Absorbed dose in EBRT
    44. 44. QA in 3D-CRT and IMRT <ul><li>Previous ICRU 5% point-dose accuracy specification replaced by a volumetric dose accuracy specification. </li></ul><ul><li>Proposed new ICRU volumetric dose accuracy specification: </li></ul><ul><ul><li>High gradient (≥ 20%/cm): 85% of points within 5mm, </li></ul></ul><ul><ul><li>Low gradient (< 20%/cm): 85% of points within 5% of predicted dose normalized to the prescribed dose. </li></ul></ul>Absorbed dose in EBRT
    45. 45. ICRU committee for 3D-CRT and IMRT ICRU IMRT report GTV 1 CTV 1 PTV 1 CTV 2 PTV 2 CTV 3 PTV 3 Microscopic Extension Regional Involvement
    46. 46. Example 1 ICRU IMRT report Target volumes in EBRT PTV 1 : dose 1 CTV 1 PTV 2 : dose 2 GTV 1 (pre-RxTh CT+ iv contrast) CTV 2 = GTV 1
    47. 47. Dose-Volume Reporting D 50 best corresponds to the level at D ICRU-point Absorbed dose in EBRT 0 10 20 30 40 50 60 70 80 90 100 0 5 10 15 20 25 30 35 40 45 50 55 60 65 Dose (Gy) Percent Volume Differential Cumulative D 95 D 98 D 50 D 2 D 50 = 60 Gy

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