1 / 16

Tumor Localization Techniques

Tumor Localization Techniques. Richard Kao April 10, 2001 Computer Integrated Surgery II. Current Oncology Research. Tumor Localization Pre-operative localization techniques that provide the greatest accuracy before irradiating the lesion area Prevent tumor extension after treatment.

abiola
Download Presentation

Tumor Localization Techniques

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Tumor Localization Techniques Richard Kao April 10, 2001 Computer Integrated Surgery II

  2. Current Oncology Research • Tumor Localization • Pre-operative localization techniques that provide the greatest accuracy before irradiating the lesion area • Prevent tumor extension after treatment

  3. Definitions • Clinical Target Volume (CTV) • Area to be irradiated, built from 3-D imaging modalities • Delineation • Outlining the area of the tumor, including providing a perimeter to prevent tumor extension

  4. Three Techniques • CT and/or MRI • Hookwire Localization • Bioimpedance

  5. Papers • Jansen, E. et al. “Target volumes in radiotherapy for high-grade malignant glioma of the brain.” Radiotherapy and Oncology, vol. 56, pp. 151-156, 2000. • Sato, M. et al. “Laparoscopic hepatic surgery guided by hookwire localization.” 2000. • Lee, B. et al. “Bioimpedance: Novel Use of a Minimally Invasive Techniques for Cancer Localization in the Intact Prostrate.” The Prostrate, vol. 39, pp. 213-218, 1999.

  6. CT • Computerized Tomography (CT) • Provides geometric superiority • 2-cm margin of error after postmortem analysis • Radiation

  7. MRI • Magnetic Resonance Imaging (MRI) • Provides diagnostic superiority • 2-3 cm margin of error after postmortem analysis • Availability and costs

  8. Jansen’s Findings • Patients had high-grade malignant astrocytoma, most common primary brain tumor • Found a lack of uniform guidelines • Discrepancy between tumor extension and CT and/or MRI results • Trade-off between probability of complications and the expected benefit for the patient • Had to add a 2-cm ring around images

  9. Jansen’s Findings (cont.) • CT and MRI separately provide good information on both macro- and microscopic tumor extension • Ideal situation is to use both • For CTVs less than 250 cm3, use single CTV • For larger tumors, use a second TV with a smaller margin of irradiation

  10. Sato’s Findings • Patients with small Hepatocellular Carcinomas (HCCs) • Helical and angiographic CT used to locate these lesions • Use CT to guide a 21-gauge guide needle to the lesion, then insert a hookwire through needle and withdraw the needle, leaving hookwire in place

  11. Hookwire Localization • CT used to confirm hookwire in place • Microwave Coagulation Therapy (MCT) on HCCs • Complete tumor ablation • Radiation

  12. Bioimpedance • Electrical property of biological tissue • Electric current is limited in living tissue by highly insulating cell membranes • Different tissue architecture may impede current differently, allowing detection of differences between normal and cancerous tissue

  13. Lee’s Findings • Prostrate cancer diagnosed by transrectal ultrasound-guided sextant needle biopsy • Imprecise method • Use two bioimpedance needles 1 mm apart, 3 mm into prostrate surface

  14. Lee’s Findings (cont.) • Cancerous areas had higher impedance (932 + 170 ohms) • Non-cancerous tissue had lower impedance (751 + 151 ohms) • Bioimpedance successful but still invasive and imprecise for different types

  15. Conclusions • CT with MRI is effective but brings up questions regarding radiation and availability • Hookwire Localization requires CT scans both pre- and postoperation • Bioimpedance successful, but invasive and not appropriate for all types of tumor localization

  16. Conclusions (cont.) • Using amorphous wires and magnetic fields to implement the Barkhausen effect, we provide a precise, reliable alternative that is readily available • Avoid pitfalls of these other techniques • Applicable to more areas than tumor localization, including catheter tip location, seed implants in brachytherapy, and probe tip location in surgical procedures

More Related