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Dosimetric comparison of large field widths in helical tomotherapy for intracranial stereotactic radiosurgery
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| A. Watcharawipha, I. Chitapanarux, B. Jia-Mahasap |
| Division of Radiation Oncology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand , imjai@hotmail.com |
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Abstract: (542 Views) |
Background: The Helical Tomotherapy (HT) technique has been introduced for use in Stereotactic Radiosurgery (SRS). Previously, the smallest field width (FW) has been recommended for optimum results, which would require a long beam-on time (BoT). The uncertainty of the intrafraction could be maximized during the delivery by this BoT. This study then investigated the plan qualities and dosimetric parameters among different FWs and treatment modes. Materials and Methods: Fifteen patients previously treated by the HT technique with fixed-FW 10 mm (FW10f) were selected. The treatment planning systems of TomoTherapy involved other plans that employed fixed-FW 25 mm (FW25f) and dynamic-FW 25 mm (FW25d). The plan quality indexes and the dosimetric parameters of the large FWs (FW 25 mm) were compared according to the FW10f benchmark and then analyzed by relevant statistics. Results: The plan quality indexes and the dosimetric parameters revealed no significant differences between FW10f and FW25d. Accordingly, FW25f revealed a significant difference in the FW10f values in some indexed parameters. The maximum dose on the right optic nerves and the value of the integral dose revealed a significant difference between FW10f and FW25f. The BoT of the FW10f presented the longest treatment time when compared with the other FWs. Conclusion: The outcomes of this investigation clearly ensure that the performance of FW25d is comparable with that of FW10f in terms of the plan qualities and the dosimetric parameters. Notably, the short BoT of this FW might benefit the minimization that is associated with intrafraction uncertainty. |
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| Keywords: Dynamic jaws, field width, stereotactic radiosurgery, helical tomotherapy. |
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Full-Text [PDF 1897 kb]
(402 Downloads)
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Type of Study: Original Research |
Subject:
Radiation Biology
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