Image-Guided Rhenium-186 NanoLiposome (186RNL) Brachytherapy in the Treatment of Recurrent Glioblastoma: Technique, Image Analysis, Dosimetry, and Monitoring

J. Floyd, A. Bao, W. Phillips, T. Patel, G. Stein, M. Hedrick, C. Rice, A. Brenner

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PURPOSE/OBJECTIVE(S): While external beam radiation therapy (EBRT) remains a central component of the management of gliomas, it is limited by tolerance of the surrounding normal brain tissue. We hypothesized that Rhenium-186 NanoLiposome (186RNL) brachytherapy will permit the selective delivery of high specific activity beta-emitting radiation with excellent retention in the tumor and that the emitted gamma rays will permit real time image-guided delivery and monitoring. Herein, we report the technique used, imaging of the nanoliposome distribution and retention, image analysis, radiation dosimetry, and therapy monitoring. MATERIALS/METHODS: A Phase 1 clinical trial of 186RNL administered by convection enhanced delivery (CED) through a flexible subacute catheter to treat recurrent glioblastoma was conducted. Rhenium-186 (186Re) is a therapeutic radionuclide (half-life: 89.24 hours) emitting beta-radiation particles (path range: 1.8 mm). One of every 10 emissions is associated with a 137 KeV gamma ray allowing imaging of in vivo drug distribution, retention, and absorbed dose determination. Treatment planning software and a frameless universal instrument holder system were used for treatment planning and catheter placement. The retention and distribution of 186RNL within the tumor and whole body were obtained by planar and SPECT/CT imaging from mid-infusion to 8 days following drug administration. Locoregional and whole-body drug retention were analyzed from whole body planar images. SPECT/CT and follow-up MR images were co-registered to planning MR images for 3D drug distribution and therapy evaluation. Radiation absorbed doses to local volumes and whole-body organs were calculated. RESULTS: 186RNL delivered by CED to patients with recurrent glioblastoma results in predictable and stable drug distribution to the targeted tissues, providing days of sustained, localized radiation treatment to the tumor. The use of up to four catheters effectively enhances locoregional drug distribution and tumor volume coverage. The mean locoregional retention in the brain volume at the end of infusion was 85.9% ± 17.1% ID (n = 18) and at 8 days post-infusion was 46.6% ± 16.7% ID (n = 17). Following dose escalation, the mean radiation absorbed dose in the two most recent cohorts to the tumor volume was 354.7 ± 144.0 Gy, to the whole brain was 1.32 ± 1.06 Gy, and to the whole body was 0.16 ± 0.04 Gy (n = 6). An analysis of 3D drug distribution and tumor response as measured by follow-up MR images will be presented. CONCLUSION: 186RNL brachytherapy provides a high radiation absorbed dose to the tumor with minimal brain and whole-body radiation exposure. The image monitoring capability can provide a predictive tool to evaluate therapy delivery and treatment effectiveness. AUTHOR DISCLOSURE: J. Floyd: Department of Neurosurgery; University of Texas Health Science Center San Antonio. A. Bao: Consultant; Plus Therapeutics. Consultant of an NIH grant supported clinical trial; University of Texas Health Science Center San Antonio. Partnership; NanoTx. W. Phillips: Consultant; Plus Therapeutics. Partnership; NanoTx. T. Patel: Partner; Surgical Group of North Texas. Honoraria; Elekta. Stock; Edwards Life Sciences, Gilead, Stryker, Ziopharm. Secretary; Texas Association of Neurological Surgeons. G. Stein: None. M. Hedrick: None. C. Rice: None. A. Brenner: Consultant; Plus Therapeutics. Partnership; NanoTx. Administrative; NanoTx.

Original languageEnglish (US)
Pages (from-to)e589
JournalInternational journal of radiation oncology, biology, physics
Issue number3
StatePublished - Nov 1 2021

ASJC Scopus subject areas

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


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