- •The effect of magnetic field on two QED™ detector was investigated for clinical use.
- •Angular dependence, response on depth, and output factor were evaluated.
- •Black QED on surface requires the correction for directions and magnetic-field.
- •Blue QED does not require correction for clinical use.
To evaluate the effect of a low magnetic field (B-field, 0.35 T) on QED™ for clinical use.
Black and Blue QED were irradiated using tri-Co-60 magnetic resonance image-guided radiation therapy systems with and without the B-field. For both detectors, angular dependence of the beam orientation was evaluated by rotating the gantry and detector in parallel and perpendicular directions to the B-field. Angular dependence between the directions of both QED and B-field was also measured. Response on the depth and output factor of both detectors was investigated for parallel and perpendicular setups, respectively.
When Black QED was placed on a surface, detector response decreased by 1.8% and 4.5% for parallel and perpendicular setups, respectively, owing to the B-field. The angular dependence of the beam orientation was not affected by B-field for both detectors. There was a significant angular dependence between Black QED and B-field direction and for the Black QED when the gantry was rotated. Owing to the B-field, the detector response at 90° decreased by 2.4%, response of Black QED on the depth was changed only on the surface, and output factor of Black QED was changed only on the surface. The response of Blue QED was not affected by the B-field for all examined situations.
Using Black QED on a surface in the same position as that in the calibration requires some correction to the B-field. Blue QED does not require correction as it is not affected by the B-field.
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- RapidArc® vs intensity-modulated radiation therapy for hepatocellular carcinoma: a comparative planning study.Br J Radiol. 2012; 85: e323-e329
- A comprehensive comparison of IMRT and VMAT plan quality for prostate cancer treatment.Int J Radiat Oncol Biol Phys. 2012; 83: 1169-1178
- An investigation of dose and quality in clinical IGRT imaging protocols.Phys Med: Eur J Med Phys. 2015; 31: S12
- Characterization of the onboard imaging unit for the first clinical magnetic resonance image guided radiation therapy system.Med Phys. 2015; 42: 5828-5837
- Set-up errors in head and neck cancer treated with IMRT technique assessed by cone-beam computed tomography: a feasible protocol.Radiat Oncol J. 2018; 36: 54
- Gross tumor volume dependency on phase sorting methods of four-dimensional computed tomography images for lung cancer.Radiat Oncol J. 2017; 35: 274
- Modern radiation therapy for extranodal lymphomas: field and dose guidelines from the international lymphoma radiation oncology group.Int J Radiat Oncol Biol Phys. 2015; 92: 11-31
- The design and implementation of a novel compact linear accelerator-based magnetic resonance imaging-guided radiation therapy (MR-IGRT) system.Int J Radiat Oncol Biol Phys. 2016; 96: E641
- Real-time volumetric relative dosimetry for magnetic resonance—image-guided radiation therapy (MR-IGRT).Phys Med Biol. 2018; 63045021
- First patients treated with a 1.5 T MRI-Linac: clinical proof of concept of a high-precision, high-field MRI guided radiotherapy treatment.Phys Med Biol. 2017; 62: L41
- The future of MRI in radiation therapy belongs to integrated MRI-linac systems, not the standalone MRI-Sim.Med Phys. 2017; 44: 791-794
- Computerized triplet beam orientation optimization for MRI-guided Co-60 radiotherapy.Med Phys. 2016; 43: 5667-5675
- Commissioning experience of tri-cobalt-60 MRI-guided radiation therapy system.Prog Med Phys. 2015; 26: 193-200
- Implementation of AAPM's TG-51 protocol on Co-60 MRI-guided radiation therapy system.Prog Med Phys. 2017; 28: 190-196
- A comparison of treatment plan quality between Tri-Co-60 intensity modulated radiation therapy and volumetric modulated arc therapy for cervical cancer.Phys Med. 2017; 40: 11-16
- Quality of tri-Co-60 MR-IGRT treatment plans in comparison with VMAT treatment plans for spine SABR.Br J Radiol. 2016; 90: 20160652
- Treatment plan comparison between Tri-Co-60 magnetic-resonance image-guided radiation therapy and volumetric modulated arc therapy for prostate cancer.Oncotarget. 2017; 8: 91174
- A treatment planning comparison between modulated tri-cobalt-60 teletherapy and linear accelerator-based stereotactic body radiotherapy for central early-stage non-small cell lung cancer.Med Dosim. 2016; 41: 87-91
- A comparative planning study for lung SABR between tri-Co-60 magnetic resonance image guided radiation therapy system and volumetric modulated arc therapy.Radiother Oncol. 2016; 120: 279-285
- Magnetic field effects on Gafchromic-film response in MR-IGRT.Med Phys. 2016; 43: 6552-6556
- Feasibility of dosimetry with optically stimulated luminescence detectors in magnetic fields.Radiat Meas. 2017; 106: 346-351
- Investigation of magnetic field effects on the dose–response of 3D dosimeters for magnetic resonance–image guided radiation therapy applications.Radiother Oncol. 2017; 125: 426-432
- Reference dosimetry in magnetic fields: formalism and ionization chamber correction factors.Med Phys. 2016; 43: 4915-4927
- Response measurement for select radiation detectors in magnetic fields.Med Phys. 2015; 42: 2837-2840
- In vivo dosimetry using a single diode for megavoltage photon beam radiotherapy: Implementation and response characterization.J Appl Clin Med Phys. 2001; 2: 210-218
- In vivo dosimetry during external photon beam radiotherapy.Int J Radiat Oncol Biol Phys. 1999; 43: 245-259
- Development of diode based high energy X-ray spatial dose distribution measuring device.J Radiat Protect. 2018; 43: 97-106
- Relative dosimetry with an MR-linac: response of ion chambers, diamond, and diode detectors for off-axis, depth dose, and output factor measurements.Med Phys. 2018; 45: 884-897
- Temperature dependence of commercially available diode detectors.Med Phys. 2002; 29: 622-630
- Entrance dose measurements for in-vivo diode dosimetry: Comparison of correction factors for two types of commercial silicon diode detectors.J Appl Clin Med Phys. 2000; 1: 100-107
- Spiraling contaminant electrons increase doses to surfaces outside the photon beam of an MRI-linac with a perpendicular magnetic field.Phys Med Biol. 2018; 63095001
Sun Nuclear Corporation. QED™ Detector User's Guide.
- Magnetic-field-induced dose effects in MR-guided radiotherapy systems: dependence on the magnetic field strength.Phys Med Biol. 2008; 53: 909
- In-vivo radiation diode dosimetry for therapeutic photon beams.([Graduate Theses and Dissertations]) University of South Florida, 2007
- Minimizing the magnetic field effect in MR-linac specific QA-tests: the use of electron dense materials.Phys Med Biol. 2016; 61: N50
- The ViewRay system: magnetic resonance–guided and controlled radiotherapy.Sem Radiat Oncol. 2014; 24: 196-199
- Comparison of onboard low-field magnetic resonance imaging versus onboard computed tomography for anatomy visualization in radiotherapy.Acta Oncol. 2015; 54: 1474-1482
- Image-guided radiation therapy: Emergence of MR-guided radiation treatment (MRgRT) systems.Phys Med Imag: Int Soc Opt Photon. 2010; 7622: 762202
Published online: April 04, 2019
Accepted: April 1, 2019
Received in revised form: March 18, 2019
Received: September 13, 2018
© 2019 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.