coefficient EXCEPT PARALLEL PLATE CHAMBERS AAPM recommendation is to cross calibrate parallel plate chamber with cylindrical chamber in a high energy electron beam (worksheet C a la TG-39) ADCL N – good TG-51 k –

2020年7月14日 · What is an ADCL? Accredited Dosimetry Calibration Laboratory (the SSDL equivalent in North America but different...) Accredited by the AAPM Provides calibrations to users for instruments and radioactive sources for dosimetry in radiotherapy and diagnostic imaging Currently three ADCLs: University of Wisconsin (Madison)

Explicit application of TG-51 to a high energy accelerator with electron capability requires the clinical physicist to have a 1mm thick sheet of lead and a parallel plate chamber. Many clinical physicists have neither, therefore we have studied the impact of alternative measurement techniques on output calibration to solve this problem.

• All chambers must have an ADCL calibration coefficient EXCEPT PARALLEL PLATE

AAPM TG-51 is the current standard for clinical dosimetry for high-energy photon and electron fields. It is the direct predecessor of TG-21 with a focus on simplicity and human error reduction. This simplification was accomplish primarily through three important changes. First, the use of plastic phantoms in primary dosimetry was eliminated.

There is nothing inherently wrong with the parallel-plate configuration More recent measurements indicate better performance – but still not as good as cylindrical chambers

The TG51/TG21 dose ratios presented here are based on the dosimetry factors provided by the two protocols and the chamber-specific absorbed dose and exposure calibration factors (N60Co (D,w) and Nx) provided by the Accredited Dosimetry Calibration Laboratory (ADCL) at The University of Texas, M. D. Anderson Cancer Center (MDACC).

to make specific recommendations for the calibration of plane-parallel chambers by the Accredited Dosim etry Calibration Laboratories (ADCLs), and to provide guidelines, following the 1983 AAPM pro tocol, for the determination of absorbed dose from high energy electron beams using the calibrated plane-parallel chambers.

The RPC considers it advisable to obtain an ADCL calibration for comparison, and to satisfy state and local regulations. Recall that the TG-51 protocol specifically advises against the use of parallel plate chambers for photon beams.

All chambers must have an ADCL calibration coefficient EXCEPT PARALLEL PLATE CHAMBERS AAPM recommendation is to cross calibrate parallel plate chamber with cylindrical chamber in a high energy electron beam (worksheet C a la TG-39) ADCL N good D,w TG-51 k