منابع مشابه
The helical tomotherapy thread effect.
Inherent to helical tomotherapy is a dose variation pattern that manifests as a "ripple" (peak-to-trough relative to the average). This ripple is the result of helical beam junctioning, completely unique to helical tomotherapy. Pitch is defined as in helical CT, the couch travel distance for a complete gantry rotation relative to the axial beam width at the axis of rotation. Without scattering ...
متن کاملAbstractID: 8177 Title: A Clinical Example of the Helical Tomotherapy Thread Effect: Robustness Discussion
ID: 8177 Title: A Clinical Example of the Helical Tomotherapy Thread Effect: Robustness Discussion Purpose: A previous study explained why pitches of 0.86/n, where n is an integer, will provide the best junctioning of a helically delivered and diverging beam. The previous treatment was theoretical and based on unmodulated examples. In this study, a clinically relevant case of a palliative lung ...
متن کاملRadiation characteristics of helical tomotherapy.
Helical tomotherapy is a dedicated intensity modulated radiation therapy (IMRT) system with on-board imaging capability (MVCT) and therefore differs from conventional treatment units. Different design goals resulted in some distinctive radiation field characteristics. The most significant differences in the design are the lack of flattening filter, increased shielding of the collimators, treatm...
متن کاملClinical helical tomotherapy commissioning dosimetry.
Helical tomotherapy presented many unique dosimetric challenges and solutions during the initial commissioning process, and some of them are presented. The dose calculation algorithm is convolution/superposition based. This requires that the energy fluence spectrum and magnitude be quantified. The methodology for doing so is described. Aspects of the energy fluence characterization that are uni...
متن کاملProstate Helical Tomotherapy: A semi-empirical estimation of the scaling factor based on 2D approximating field
Background: In Helical Tomotherapy (HT), the scaling factor (SF) is the time in seconds that each leaf viewing a target would need to be open to deliver the prescribed dose. The SF is patient-specific and is used to calculate the rotational period of the gantry, and the total treatment time (TTT) of the HT. The SF is generally difficult to estimate. Currently, it takes about one hour t...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Medical Physics
سال: 2005
ISSN: 0094-2405
DOI: 10.1118/1.1896453