Spatial dose distributions in solid tumors from 186Re transported by liposomes using HS radiochromic media

Luis A. Medina, Beth Goins, Mercedes Rodríguez-Villafuerte, Ande Bao, Arnulfo Martínez-Davalos, Vibhudutta Awasthi, Olga O. Galván, Cristina Santoyo, William T. Phillips, María Ester Brandan

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Purpose: A procedure for the measurement of spatial dose rate distribution of beta particles emitted by 186Re-liposomes in tumoral tissue, using HS GafChromic films, is presented. Methods: HNSCC xenografts were intratumorally injected with 3.7 or 11.1 MBq of 186Re-liposomes, and planar gamma camera images were acquired to determine the liposome retention in the tumor. After imaging, rats were sacrificed and tumors were excised and processed in slices; HS film sections were placed between slices and the tumor lobe was reassembled. Tumors and films were kept in the dark at 4°C for 18 h. After irradiation, films were removed and response was read using a transmission scanner. Films were analyzed to determine two-dimensional spatial dose rate distributions and cumulative dose volume histograms. Dose rate distributions were quantified using a 60Co calibration curve, the 186Re physical half-life, and a perturbation factor that takes into account the effect of the film protective layer. Results: Dose rate distributions are highly heterogeneous with maximal dose rates about 0.4 Gy h-1 in tumors injected with 3.7 MBq and 1.3 Gy h-1 in tumors injected with 11.1 MBq. Dose volume histograms showed dose distributed in more than 95% and 80% of the tumor when injected with the lower and the higher activity, respectively. Conclusion: The described procedures and techniques have shown the potential and utility of HS GafChromic film for determination of dose rate distributions in solid tumors injected intratumorally with 186Re-liposomes. The film's structure and the liposomes' biodistribution must be taken into account to obtain quantitative dose measurements.

Original languageEnglish (US)
Pages (from-to)1039-1049
Number of pages11
JournalEuropean Journal of Nuclear Medicine and Molecular Imaging
Volume34
Issue number7
DOIs
StatePublished - Jul 2007

Keywords

  • HS Gafchromic film
  • Intratumoral dosimetry
  • Liposomes
  • MC simulation
  • Radionuclide therapy
  • Re

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

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