Qing Liang, PhD Medical Physicist Mercy Health System, Janesville, WI Dose Measurement Qing Liang, PhD Medical Physicist Mercy Health System, Janesville, WI
Learning Objectives Learn about ionization calibration chain Understand TG51 on photon beam and electron beam dosimetry Overview of TRS398
References AAPM TG 51: Med Phys 26(9), 1999 AAPM TG 51 Addendum 41(4),2014 IAEA TRS 398 Khan, The Physics of Radiation Therapy AAPM virtual library (website)
Part 1: Calibration Traceability (ionization chamber)
Calibration Chain 2009AAPM summer school
What is a PSDL? 2009AAPM summer school
Primary Dosimetry Standard 2009AAPM summer school
Secondary Standard Dosimetry Lab 2009AAPM summer school
NIST National Institute of Standard and Technology Dose measured by calorimeter, 60Co source NIST calibrated chamber :Absorbed dose in water rate (Gy/s) I: ionization current (C/s)
ADCL 2009AAPM summer school
Clinical calibration factor NIST ADCL ADCL ADCL Clinic Clinic Clinic Clinic Clinic Clinic
Part 2: AAPM TG51
AAPM TG51
AAPM TG51
TG51 Overview: photon 2009AAPM summer school
TG51 Overview: electron 2009AAPM summer school
TG51 Overview 2009AAPM summer school
TG51 Overview 2009AAPM summer school
TG51 Overview 2009AAPM summer school
TG51 Phantom 2009AAPM summer school
TG51 Chamber 2009AAPM summer school
TG51 Effective point of Measurement 2009AAPM summer school
TG51 Effective point of Measurement 2009AAPM summer school
TG51 Chamber Reading Pion: recombination correction factor Two voltage method (<1.05)
TG51 Chamber Reading PTP: temperature pressure correction Correct for density compare to standard environmental condition: 22oC, 101.33 kPa (760 mm Hg)
TG51 Chamber Reading Pelec: electrometer calibration factor Provided by ADCL Unit: C/C or C/rdg If calibrated with chamber, Pelec=1 If calibrated separately, Pelec applied
TG51 Chamber Reading Ppol: polarity correction factor Depends on chamber design, cable position and beam quality (0.97-1.03)
TG51 Beam Quality (P) 2009AAPM summer school
TG51 Beam Quality (P) 2009AAPM summer school
TG51 Beam Quality (P) 2009AAPM summer school
TG51 Beam Quality (P) OR 2009AAPM summer school
TG51 Beam Quality (P) 2009AAPM summer school
TG51 Photon Dosimetry 2009AAPM summer school
TG51 Photon Dosimetry 2009AAPM summer school
TG51 Photon Summery 2009AAPM summer school
TG51 Worksheet (P)
TG51 Beam Quality (E) 2009AAPM summer school
TG51 Beam Quality (E) 2009AAPM summer school
TG51 Beam Quality (E) 2009AAPM summer school
TG51 Beam Quality (E) 2009AAPM summer school
TG51 Beam Quality (E) 2009AAPM summer school
TG51 Beam Quality (E) 2009AAPM summer school
TG51 Beam Quality (E) 2009AAPM summer school
TG51 Beam Quality (E) 2009AAPM summer school
TG51 Beam Quality (E) Kecal 2009AAPM summer school
TG51 Electron Dosimetry 2009AAPM summer school
TG51 Beam Quality (E) 2009AAPM summer school
TG51 Electron Dosimetry 2009AAPM summer school
TG51 Electron Dosimetry 2009AAPM summer school
TG51 Electron Dosimetry 2009AAPM summer school
TG51 Electron Summery 2009AAPM summer school
TG51 Worksheet (E, cyl)
TG51 Worksheet (E, pp)
TG51 Summery 2009AAPM summer school
TG51 Addendum
TG51 Addendum Covers No lead foil to be used anymore (use equation)
Part 3: IAEA TRS 398
IAEA TRS 398
TRS 398 vs. TG 51 Basic equations are the same between TRS398 and TG51, expect notations Main difference is the beam quality parameter kQ: TPR20,10 in TRS 398, vs. %dd(10)x in TG51
TRS 398 Setup: SAD Source to chamber distance: 100 cm Field size: 10x10 cm2 Depth: 20 cm, 10 cm
Thank you!