Topics to be Discussed

1. Innovative Computerized Treatment Planning System for Permanent Prostate ImplantsEva K. Lee, Radiation Oncology, Emory University; Industrial & Systems Engineering, Georgia Institute of Technology.

2. Topics to be Discussed • Automated Treatment Planning System for Brachytherapy in Permanent Prostate Implants • MRS-image guided Dose-Escalation Planning • Extended-time Dose Control and Planning Taking Edema Shrinkage and Seed Displacement into Account

3. Brachytherapy for Prostate Carcinoma • Radiation therapy that involves the placement of radioactive sources permanently inside the prostate.

4. Transperineal Implantation of Radionuclides using Transrectal Ultrasound (TRUS) Device

5. Part I:Automated Treatment Planning System for Brachytherapy

6. Computerized Optimization Approach • Include strict dose bounds for different anatomies • Impose clinically desired properties • Superior plans / Time savings • Can generate a plan within 5 minutes • Allow intra-operative planning for clinicians • overcome current pre-planning problems • allow real-time alteration of plans due to unforeseen implantation problems • First-of-its-kind • Research tool to push frontier of understanding

7. Manual Plan shows poor post-implant coverage & conformity (white curve represents contour of prostateslice, green curve represents the 100% isodose curve)

8. Optimized Plan from Automated System showssuperior coverage & conformity (white curve represents contour of prostate slice, green curve represents the 100% isodose curve)

9. Part II:MRS-image guided Dose-Escalation Planning

10. MRS-Image Guided Planning • Explore feasibility of designing treatment plans with localized escalated dose in identifiable tumor regions of the prostate and gauge the biological significance of doing so. • Escalate dose in tumor regions within prostate identified by MRS-images • Case study of a patient shows drastic improvement of tumor control probability from 65% to 95% in dose escalated plans

11. Example of dose escalation around the tumor region:

12. Here the tumor spot is in the vicinity of the urethra: the dose received by the urethra is kept within strict pre-set levels and reasonable escalation is observed in the tumor area.

13. Estimated Tumor Control Probability (TCP) values for 3 different tumor volumes: MRS-guided and standard plans MRS-guided plan appears consistently superior to the non-dose-escalated (standard) plan.

14. Part III:Extended-time Dose Control and Planning Taking Edema Shrinkage and Seed Displacement into Account

15. Automated Planning with Extended Dose Control • Patient case studies reveal excessive irradiation to prostate exterior, urethra and rectum when no extended dosimetric constraints, seed displacement or gland shrinkage information are included in the planning process. • Dosimetric control of irradiation to the prostate, urethra and rectum; seed displacement; and gland shrinkage information are incorporated into planning over the entire 30 day period.

16. Automated Planning with Extended Dose Control: Findings • Multi-period planning provides conformal dosimetry to the gland over a period of 30 days, and a reduction of over 21% of external normal tissue receiving excessive irradiation. • Multi-period planning demonstrates the potential for urethra and rectum morbidity reduction without compromising local tumor control.

17. The figure below shows a plot of coverage and conformity scores over the 30-day horizon for several multi-period plans. For comparison, the single-period EPV[0] plan's 30-day coverage and conformity plot is also shown. Note that while initial coverage is somewhat better for EPV[0] than for the multi-period plans, overall conformity for EPV[0] is much worse.The lines with values above (below) 1.0 on the vertical axis correspond to the conformity (coverage) indices for the six plans.

19. References • E.K. Lee, M. Zaider, Intra-Operative Iterative Treatment-Plan Optimization for Prostate Permanent Implants. 2nd International Innovative Solutions for Prostate Cancer Care meeting, 32-33, 2001. • M. Zaider, E.K. Lee, MRS-guided Dose-Escalation Treatment Planning Optimization for Permanent Prostate Implants. 2nd International Innovative Solutions for Prostate Cancer Care meeting, 36, 2001. • E.K. Lee, M. Zaider, Determining an Effective Planning Volume for Permanent Prostate Implants. International Journal of Radiation Oncology, Biology and Physics, 49(5) (2001), in print. • M. Zaider, M. Zelefsky, E.K. Lee, K. Zakian, H.A. Amols, J. Dyke, J. Koutcher. Treatment Planning for Prostate Implants Using MR Spectroscopy Imaging. International Journal of Radiation Oncology, Biology and Physics, 47(4): 1085-96 (2000) • E.K. Lee, R. Gallagher, M. Zaider, Planning implants of radionuclides for the treatment of prostate cancer: an application of mixed integer programming. Optima (Mathematical Programming Society Newsletter), feature article, 1999; 61: 1 – 10.

20. References • C.S. Wuu, R.D. Ennis, P.B. Schiff, E.K. Lee, M. Zaider, Dosimetric and Volumetric Criteria for Selecting a Source Type I-125 or Pd-103 and Source Activity in the Presence of Irregular Seed Placement in Permanent Prostate Implants. International Journal of Radiation Oncology, Biology and Physics, 47: 815-820 (2000). • E.K. Lee, R. Gallagher, D. Silvern, C.S. Wuu, and M. Zaider, Treatment Planning for Brachytherapy: An Integer Programming Model, Two Computational Approaches and Experiments with Permanent Prostate Implant Planning. Physics in Medicine and Biology Vol. 44 (1), pp.~145-165, 1999. • D. Silvern, E.K. Lee, R. Gallagher, L.G. Stabile, R.D. Ennis, C.R. Moorthy, and M. Zaider, Treatment Planning for Permanent Prostate Implants: Genetic Algorithm versus Integer Programming. Medical & Biological Engineering & Computing, vol.~35, Supplement Part 2, 1997. • R. Gallagher, E.K. Lee, Mixed Integer Programming Optimization Models for Brachytherapy Treatment Planning. In: Daniel R. Masys, Ed. Proceedings of the 1997 American Medical Informatics Association Annual Fall Symposium, 278-282, 1997.