Spatial dose distributions in solid tumors from 186Re transported by liposomes using HS radiochromic media
Por:
Medina L.A., Goins B., Rodríguez-Villafuerte M., Bao A., Martínez-Davalos A., Awasthi V., Galván O.O., Santoyo C., Phillips W.T., Brandan M.-E.
Publicada:
1 ene 2007
Categoría:
Radiology, Nuclear Medicine and Imaging
Resumen:
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. © 2007 Springer-Verlag.
Filiaciones:
Medina L.A.:
Instituto de Física, UNAM, A.P. 20-364, México 01000 D.F., Mexico
Goins B.:
Department of Radiology, University of Texas, Health Science Center at San Antonio, San Antonio, TX, United States
Rodríguez-Villafuerte M.:
Instituto de Física, UNAM, A.P. 20-364, México 01000 D.F., Mexico
Bao A.:
Department of Radiology, University of Texas, Health Science Center at San Antonio, San Antonio, TX, United States
Department of Otolaryngology-Head and Neck Surgery, University of Texas, Health Science Center at San Antonio, San Antonio, TX, United States
Martínez-Davalos A.:
Instituto de Física, UNAM, A.P. 20-364, México 01000 D.F., Mexico
Awasthi V.:
Department of Radiology, University of Texas, Health Science Center at San Antonio, San Antonio, TX, United States
Galván O.O.:
Instituto de Física, UNAM, A.P. 20-364, México 01000 D.F., Mexico
Santoyo C.:
Department of Radiology, University of Texas, Health Science Center at San Antonio, San Antonio, TX, United States
Phillips W.T.:
Department of Radiology, University of Texas, Health Science Center at San Antonio, San Antonio, TX, United States
Brandan M.-E.:
Instituto de Física, UNAM, A.P. 20-364, México 01000 D.F., Mexico
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