First radiotherapy of human metastatic brain tumors delivered by a computerized tomography scanner (CTRx)

J. Holt Rose, Amos Norman, Marylou Ingram, Chuck Aoki, Tim Solberg, Albert Mesa

Research output: Contribution to journalArticle

78 Scopus citations

Abstract

Purpose: This Phase I study was designed to evaluate the computed tomography (CT) scanner as a device for radiation therapy of human brain tumors (CTRx). This first use in humans of a modified CT for treatment was founded on extensive research experience with canine tumors. An additional objective was to increase the therapeutic radiation dose to tumors compared to normal tissue by concentration of infused contrast material in tumors, an effect available at diagnostic x-ray energies but not at megavoltage energies. Methods and Materials: A small metastatic brain tumor in each of eight patients received 3-5-weekly fractions of 5 Gy equivalent per fraction from a CT scanner modified to deliver radiation therapy. In each patient, one additional tumor, lying completely outside the volume treated by CTRx, served as a control. The tumor receiving CTRx was treated after infusion of iodinated x-ray contrast media (CM) for dose enhancement. Many of these patients also received conventional 40 Gy whole brain radiation, before, during, or after CTRx treatment. Results: None of the patients showed adverse reactions to the CM or necrosis of the normal brain from the CTRx boost radiation. Monte Carlo calculations of the radiation dose distributions in a model tumor showed that the CTRx irradiation of tumors carrying 10 mg or more of iodine per gram of tumor was as good or better than the dose distribution from conventional 10-MV X-rays. The treated tumor in two of the patients vanished after four treatments, whereas a control tumor in one patient remained constant and grew 4-fold in another patient. Conclusion: The CTRx concept effectively combines a modified CT scanner as a diagnostic device, as a simulator dedicated to radiotherapy, and as a treatment machine. Thus, CTRx could be very useful for radiation oncologists in controlling CM-enhanced and other small brain tumors.

Original languageEnglish (US)
Pages (from-to)1127-1132
Number of pages6
JournalInternational Journal of Radiation Oncology Biology Physics
Volume45
Issue number5
DOIs
StatePublished - Dec 1 1999

Keywords

  • Brain radiotherapy
  • CT
  • Radiation dose enhancement
  • Radiosurgery
  • Stereotactic techniques

ASJC Scopus subject areas

  • Radiation
  • Oncology
  • Radiology Nuclear Medicine and imaging
  • Cancer Research

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