TY  - JOUR
AU  - Höfel, Sebastian
AU  - Liebig, Pauline
AU  - Fix, Michael K
AU  - Drescher, Malte
AU  - Zwicker, Felix
TI  - Adapting a practical EPR dosimetry protocol to measure output factors in small fields with alanine.
JO  - Journal of applied clinical medical physics
VL  - 24
IS  - 12
SN  - 1526-9914
CY  - Reston, Va.
PB  - ACMP
M1  - DKFZ-2023-02258
SP  - e14191
PY  - 2023
N1  - #LA:E055# / 2023 Dec;24(12):e14191
AB  - Modern radiotherapy techniques often deliver small radiation fields. In this work, a practical Electron Paramagnetic Resonance (EPR) dosimetry protocol is adapted and applied to measure output factors (OF) in small fields of a 6 MV radiotherapy system. Correction factors and uncertainties are presented and OFs are compared to the values obtained by following TRS-483 using an ionization chamber (IC).Irradiations were performed at 10 cm depth inside a water phantom positioned at 90 cm source to surface distance with a 6 MV flattening filter free photon beam of a Halcyon radiotherapy system. OFs for different nominal field sizes (1 × 1, 2 × 2, 3 × 3, 4 × 4, normalized to 10 × 10 cm2 ) were determined with a PinPoint 3D (PTW 31022) IC following TRS-483 as well as with alanine pellets with a diameter of 4 mm and a height of 2.4 mm. EPR readout was performed with a benchtop X-band spectrometer. Correction factors due to volume averaging and due to positional uncertainties were derived from 2D film measurements.OFs obtained from both dosimeter types agreed within 0.7
KW  - EPR dosimetry (Other)
KW  - alanine (Other)
KW  - density effect (Other)
KW  - output factor (Other)
KW  - small field (Other)
KW  - volume effect (Other)
LB  - PUB:(DE-HGF)16
C6  - pmid:37922380
DO  - DOI:10.1002/acm2.14191
UR  - https://inrepo02.dkfz.de/record/285223
ER  -