Abstract
Purpose:Advances in radiation treatment especially with smaller fields used in SRS, Gamma knife, Tomotherapy, Cyberknife, and IMRT, require a high degree of precision especially with microdetectors for small field dosimetry (Das et al, Med Ph, 35, 206, 2008; Alfonso et al, Med Phys, 35, 5179, 2008). Due to small signal, the triaxial cable becomes critical in terms of signal to noise ratio (SNR) which is studied with microdetectors.Methods:Six high quality triaxial cables, 9.1 meters long from different manufacturers without any defects were acquired along with 5 most popular microdetectors (microdiamond, plastic scintillators, SRS‐diode, edge‐diode and pinpoint). A dedicated electrometer was used for each combination except W1 which has its own supermax electrometer. A 6MV photon beam from Varian True beam with 100 MU at a 600 MU/min was used. Measurements were made at a depth of 5 cm in water phantom. Field sizes were varied from 0.5 cm to 10 cm square fields. Readings were taken with combination of cables and microdetectors.Results:Signal is dependent on the quality of the connectors, cables and types of microdetector. The readings varied from nC to pC depending on the type of microdetector. The net signal, S, (Sc‐Sn), where Sc is signal with chamber and Sn is without chamber is a linear function of sensitive volume, v; (S = α+β•V), where α and β are constants. The standard deviation (SD) in 3 sets of reading with each combination of cable‐detector was extremely low <0.02%. As expected the SD is higher in small fields (<3cm). Maximum estimated error was only ±0.2% in cables‐detector combinations.Conclusion:The choice of cables has relatively small effect (±0.2%) with microdosimeter and should be accounted in overall error estimation in k value that is needed to convert ratio of reading to dose in small field dosimetry.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
