Three-dimensional dose distribution for partial irradiation of rat parotid glands with 200kV X-rays.
| Autor: | Cotteleer F; Department of Radiation and Stress Cellbiology, University of Groningen, Groningen, The Netherlands., Faber H, Konings AW, Van der Hulst PC, Coppes RP, Meertens H |
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| Jazyk: | angličtina |
| Zdroj: | International journal of radiation biology [Int J Radiat Biol] 2003 Sep; Vol. 79 (9), pp. 689-700. |
| DOI: | 10.1080/09553000310001610268 |
| Abstrakt: | Purpose: To investigate dose distributions in partial-volume irradiation experiments in small experimental animals, in particular the parotid gland of rat. Materials and Methods: High-resolution magnetic resonance imaging images were made that provided the outlines of the parotid glands, which were used to design collimators with conformal radiation ports for 100 and 50% cranial/caudal partial-volume irradiation. A protocol for absolute dosimetry was designed and relative dose measurements were performed. From the three-dimensional topographical data and the three-dimensional dose distribution, dose-volume histograms were determined. Results: The standard uncertainty of absorbed entrance dose was within 3%. Radiochromic film, thermoluminescence dosemeters and ionization chamber dose measurements revealed that the relative doses measured were in good agreement. The 20-80% penumbra of the beam across the 50% field edge was only 0.4 mm at a 6 mm depth. The gradient of the percentage depth dose from the skin of the rat to a depth of 12 mm was 1.5% mm(-1). The absorbed doses in the cranial 50% and the caudal 50% partial volumes were comparable. This finding was reflected in the calculated dose-volume histograms of the different regions, which were similar. The dose in the shielded area between the left and right ports was about 14% of the dose near the centres of the beams. Conclusion: The designed set-up showed that irradiation of small volumes could be performed with high accuracy allowing the study of differences in radiation damage. Similar doses were given to the 50% cranial and 50% caudal gland volumes and, therefore, a possible difference in radiosensitivity in these volumes was not a dose effect. The approach used was also applicable for the irradiation of small volumes of other tissues. |
| Databáze: | MEDLINE |
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