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Use of an orthovoltage X-ray treatment unit as a radiation research system in a small-animal cancer model.

Medina LA, Herrera-Penilla BI, Castro-Morales MA, García-López P, Jurado R, Pérez-Cárdenas E, Chanona-Vilchis J, Brandan ME - J. Exp. Clin. Cancer Res. (2008)

Bottom Line: No measurable dose was delivered outside of the collimator apertures.Evaluation of the RTV showed a significant reduction of the tumor volume as consequence of the chemoradiotherapy treatment; results also show that toxicity was well tolerated by the animals.Results and procedures described in the present work have shown the usefulness and convenience of the orthovoltage X-ray system for animal model radiotherapy protocols.

View Article: PubMed Central - HTML - PubMed

Affiliation: Instituto de Física, Universidad Nacional Autónoma de México (UNAM), México D,F, 04510, Mexico. medina@fisica.unam.mx

ABSTRACT

Background: We explore the use of a clinical orthovoltage X-ray treatment unit as a small-animal radiation therapy system in a tumoral model of cervical cancer.

Methods: Nude mice were subcutaneously inoculated with 5 x 106 HeLa cells in both lower limbs. When tumor volume approximated 200 mm3 treatment was initiated. Animals received four 2 mg/kg intraperitoneal cycles (1/week) of cisplatin and/or 6.25 mg/kg of gemcitabine, concomitant with radiotherapy. Tumors were exposed to 2.5 Gy/day nominal surface doses (20 days) of 150 kV X-rays. Lead collimators with circular apertures (0.5 to 1.5 cm diameter) were manufactured and mounted on the applicator cone to restrict the X-ray beam onto tumors. X-ray penetration and conformality were evaluated by measuring dose at the surface and behind the tumor lobe by using HS GafChromic film. Relative changes in tumor volume (RTV) and a clonogenic assay were used to evaluate the therapeutic response of the tumor, and relative weight loss was used to assess toxicity of the treatments.

Results: No measurable dose was delivered outside of the collimator apertures. The analysis suggests that dose inhomogeneities in the tumor reach up to +/- 11.5% around the mean tumor dose value, which was estimated as 2.2 Gy/day. Evaluation of the RTV showed a significant reduction of the tumor volume as consequence of the chemoradiotherapy treatment; results also show that toxicity was well tolerated by the animals.

Conclusion: Results and procedures described in the present work have shown the usefulness and convenience of the orthovoltage X-ray system for animal model radiotherapy protocols.

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Therapeutic response (Relative Tumor Volume vs. Time) for the control and the experimental groups. Group A: cervical cancer xenografts treated with radiotherapy, cisplatin and gemcitabine as explained in the text; Group B: xenografts treated with radiotherapy and gemcitabine; Group C: untreated xenografts controls. Arrows indicate beginning and end of the treatments. Solid line signals RTV = 1, i.e. no change in tumor volume. Values are given as means ± SEM.
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Figure 7: Therapeutic response (Relative Tumor Volume vs. Time) for the control and the experimental groups. Group A: cervical cancer xenografts treated with radiotherapy, cisplatin and gemcitabine as explained in the text; Group B: xenografts treated with radiotherapy and gemcitabine; Group C: untreated xenografts controls. Arrows indicate beginning and end of the treatments. Solid line signals RTV = 1, i.e. no change in tumor volume. Values are given as means ± SEM.

Mentions: Figure 7 shows the relative tumor volume vs. time (i.e. therapeutic response) for the control and the experimental groups. The plot shows that the tumor lobe increases continuously in the control while practically disappears in the experimental groups. There was not difference in the therapeutic response between both experimental groups.


Use of an orthovoltage X-ray treatment unit as a radiation research system in a small-animal cancer model.

Medina LA, Herrera-Penilla BI, Castro-Morales MA, García-López P, Jurado R, Pérez-Cárdenas E, Chanona-Vilchis J, Brandan ME - J. Exp. Clin. Cancer Res. (2008)

Therapeutic response (Relative Tumor Volume vs. Time) for the control and the experimental groups. Group A: cervical cancer xenografts treated with radiotherapy, cisplatin and gemcitabine as explained in the text; Group B: xenografts treated with radiotherapy and gemcitabine; Group C: untreated xenografts controls. Arrows indicate beginning and end of the treatments. Solid line signals RTV = 1, i.e. no change in tumor volume. Values are given as means ± SEM.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2586013&req=5

Figure 7: Therapeutic response (Relative Tumor Volume vs. Time) for the control and the experimental groups. Group A: cervical cancer xenografts treated with radiotherapy, cisplatin and gemcitabine as explained in the text; Group B: xenografts treated with radiotherapy and gemcitabine; Group C: untreated xenografts controls. Arrows indicate beginning and end of the treatments. Solid line signals RTV = 1, i.e. no change in tumor volume. Values are given as means ± SEM.
Mentions: Figure 7 shows the relative tumor volume vs. time (i.e. therapeutic response) for the control and the experimental groups. The plot shows that the tumor lobe increases continuously in the control while practically disappears in the experimental groups. There was not difference in the therapeutic response between both experimental groups.

Bottom Line: No measurable dose was delivered outside of the collimator apertures.Evaluation of the RTV showed a significant reduction of the tumor volume as consequence of the chemoradiotherapy treatment; results also show that toxicity was well tolerated by the animals.Results and procedures described in the present work have shown the usefulness and convenience of the orthovoltage X-ray system for animal model radiotherapy protocols.

View Article: PubMed Central - HTML - PubMed

Affiliation: Instituto de Física, Universidad Nacional Autónoma de México (UNAM), México D,F, 04510, Mexico. medina@fisica.unam.mx

ABSTRACT

Background: We explore the use of a clinical orthovoltage X-ray treatment unit as a small-animal radiation therapy system in a tumoral model of cervical cancer.

Methods: Nude mice were subcutaneously inoculated with 5 x 106 HeLa cells in both lower limbs. When tumor volume approximated 200 mm3 treatment was initiated. Animals received four 2 mg/kg intraperitoneal cycles (1/week) of cisplatin and/or 6.25 mg/kg of gemcitabine, concomitant with radiotherapy. Tumors were exposed to 2.5 Gy/day nominal surface doses (20 days) of 150 kV X-rays. Lead collimators with circular apertures (0.5 to 1.5 cm diameter) were manufactured and mounted on the applicator cone to restrict the X-ray beam onto tumors. X-ray penetration and conformality were evaluated by measuring dose at the surface and behind the tumor lobe by using HS GafChromic film. Relative changes in tumor volume (RTV) and a clonogenic assay were used to evaluate the therapeutic response of the tumor, and relative weight loss was used to assess toxicity of the treatments.

Results: No measurable dose was delivered outside of the collimator apertures. The analysis suggests that dose inhomogeneities in the tumor reach up to +/- 11.5% around the mean tumor dose value, which was estimated as 2.2 Gy/day. Evaluation of the RTV showed a significant reduction of the tumor volume as consequence of the chemoradiotherapy treatment; results also show that toxicity was well tolerated by the animals.

Conclusion: Results and procedures described in the present work have shown the usefulness and convenience of the orthovoltage X-ray system for animal model radiotherapy protocols.

Show MeSH
Related in: MedlinePlus