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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.

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tumor localization techniques

Tumor Localization Techniques

Richard Kao

April 10, 2001

Computer Integrated Surgery II

current oncology research
Current Oncology Research
  • Tumor Localization
  • Pre-operative localization techniques that provide the greatest accuracy before irradiating the lesion area
  • Prevent tumor extension after treatment
  • 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
three techniques
Three Techniques
  • CT and/or MRI
  • Hookwire Localization
  • Bioimpedance
  • 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.
  • Computerized Tomography (CT)
  • Provides geometric superiority
  • 2-cm margin of error after postmortem analysis
  • Radiation
  • Magnetic Resonance Imaging (MRI)
  • Provides diagnostic superiority
  • 2-3 cm margin of error after postmortem analysis
  • Availability and costs
jansen s findings
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
jansen s findings cont
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
sato s findings
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
hookwire localization
Hookwire Localization
  • CT used to confirm hookwire in place
  • Microwave Coagulation Therapy (MCT) on HCCs
  • Complete tumor ablation
  • Radiation
  • 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
lee s findings
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
lee s findings cont
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
  • 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
conclusions cont
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