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Innovative Computerized Treatment Planning System for Permanent Prostate Implants

This presentation discusses a pioneering automated treatment planning system for brachytherapy in permanent prostate implants. The system overcomes current pre-planning issues by providing intra-operative planning and real-time alterations due to unforeseen complications. Key features include MRS-image guided dose escalation, accounting for edema shrinkage, seed displacement, and strict dose bounds. Clinical studies indicate superior coverage and conformity of localized dose escalation plans compared to traditional methods, significantly improving tumor control probability while reducing hazardous irradiation to surrounding healthy tissues.

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Innovative Computerized Treatment Planning System for Permanent Prostate Implants

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  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.

  18. 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.

  19. 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.

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