SU-E-T-101: Two-Peak Ratio Method in LiF Thermoluminescent Dosimeters to Determine the LET and the Separate Absorbed Dose Components in a Mixed Radiation Field for Applications in Radiation Therapy

2011 ◽  
Vol 38 (6Part11) ◽  
pp. 3509-3509 ◽  
Author(s):  
C Reft
Keyword(s):  
Radiation Therapy ◽  
Radiation Field ◽  
Absorbed Dose ◽  
Ratio Method ◽  
Peak Ratio ◽  
Thermoluminescent Dosimeters ◽  
Mixed Radiation Field

scholarly journals A Novel Simple Phantom for Verifying the Dose of Radiation Therapy

2015 ◽  
Vol 2015 ◽  
pp. 1-5
Author(s):  
J. H. Lee ◽  
L. T. Chang ◽  
A. C. Shiau ◽  
C. W. Chen ◽  
Y. J. Liao ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Correction Factor ◽  
Scatter Correction ◽  
Absorbed Dose ◽  
Clinical Tests ◽  
Thermoluminescent Dosimeters ◽  
Water Phantom ◽  
Audit System ◽  
Solid Water ◽  
The Difference

A standard protocol of dosimetric measurements is used by the organizations responsible for verifying that the doses delivered in radiation-therapy institutions are within authorized limits. This study evaluated a self-designed simple auditing phantom for use in verifying the dose of radiation therapy; the phantom design, dose audit system, and clinical tests are described. Thermoluminescent dosimeters (TLDs) were used as postal dosimeters, and mailable phantoms were produced for use in postal audits. Correction factors are important for converting TLD readout values from phantoms into the absorbed dose in water. The phantom scatter correction factor was used to quantify the difference in the scattered dose between a solid water phantom and homemade phantoms; its value ranged from 1.084 to 1.031. The energy-dependence correction factor was used to compare the TLD readout of the unit dose irradiated by audit beam energies with60Co in the solid water phantom; its value was 0.99 to 1.01. The setup-condition factor was used to correct for differences in dose-output calibration conditions. Clinical tests of the device calibrating the dose output revealed that the dose deviation was within 3%. Therefore, our homemade phantoms and dosimetric system can be applied for accurately verifying the doses applied in radiation-therapy institutions.

scholarly journals International recommendations for personalised selective internal radiation therapy of primary and metastatic liver diseases with yttrium-90 resin microspheres

2021 ◽  
Author(s):  
Hugo Levillain ◽  
Oreste Bagni ◽  
Christophe M. Deroose ◽  
Arnaud Dieudonné ◽  
Silvano Gnesin ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Absorbed Dose ◽  
Steering Committee ◽  
Selective Internal Radiation Therapy ◽  
Internal Radiation ◽  
Selective Internal Radiation ◽  
Internal Radiation Therapy ◽  
Resin Microspheres ◽  
Yttrium 90 ◽  
Strong Agreement

Abstract Purpose A multidisciplinary expert panel convened to formulate state-of-the-art recommendations for optimisation of selective internal radiation therapy (SIRT) with yttrium-90 (90Y)-resin microspheres. Methods A steering committee of 23 international experts representing all participating specialties formulated recommendations for SIRT with 90Y-resin microspheres activity prescription and post-treatment dosimetry, based on literature searches and the responses to a 61-question survey that was completed by 43 leading experts (including the steering committee members). The survey was validated by the steering committee and completed anonymously. In a face-to-face meeting, the results of the survey were presented and discussed. Recommendations were derived and level of agreement defined (strong agreement ≥ 80%, moderate agreement 50%–79%, no agreement ≤ 49%). Results Forty-seven recommendations were established, including guidance such as a multidisciplinary team should define treatment strategy and therapeutic intent (strong agreement); 3D imaging with CT and an angiography with cone-beam-CT, if available, and 99mTc-MAA SPECT/CT are recommended for extrahepatic/intrahepatic deposition assessment, treatment field definition and calculation of the 90Y-resin microspheres activity needed (moderate/strong agreement). A personalised approach, using dosimetry (partition model and/or voxel-based) is recommended for activity prescription, when either whole liver or selective, non-ablative or ablative SIRT is planned (strong agreement). A mean absorbed dose to non-tumoural liver of 40 Gy or less is considered safe (strong agreement). A minimum mean target-absorbed dose to tumour of 100–120 Gy is recommended for hepatocellular carcinoma, liver metastatic colorectal cancer and cholangiocarcinoma (moderate/strong agreement). Post-SIRT imaging for treatment verification with 90Y-PET/CT is recommended (strong agreement). Post-SIRT dosimetry is also recommended (strong agreement). Conclusion Practitioners are encouraged to work towards adoption of these recommendations.

scholarly journals Dosimetric Intercomparison at the Scandinavian Radiation Therapy Centres I. Absorbed Dose Intercomparison

1982 ◽  
Vol 21 (1) ◽  
pp. 1-10 ◽  
Author(s):  
K.-A. Johansson ◽  
L. O. Mattsson ◽  
H. Svensson
Keyword(s):  
Radiation Therapy ◽  
Absorbed Dose

Calculation of the radiation dose absorbed by human biological tissue when using imaging equipment in radiоtherapy

2021 ◽  
pp. 56-59
Author(s):  
Irina M. Lebedenko ◽  
Sergej S. Khromov ◽  
Taras V. Bondarenko ◽  
Evgenij M. Chertenkov
Keyword(s):  
Monte Carlo ◽  
Radiation Therapy ◽  
Biological Tissue ◽  
Electron Accelerator ◽  
Absorbed Dose ◽  
Tube Voltage ◽  
X Ray ◽  
The Monte Carlo Method ◽  
Therapeutic Procedures ◽  
Dose Control

Considered the issues of X-ray dose control during diagnostic and therapeutic procedures using imaging tools. The dose of X-ray radiation from the visualization devices absorbed by the biological tissue of a person was determined when monitoring the position of the patient on the therapeutic table of the electron accelerator before the radiation therapy session. The processes of transmission of photons and electrons through the medium were simulated, and the X-ray spectra were measured. The emission spectrum of the Varian G-242 Rotating Anode X-ray Tube was obtained using an XR-100-CdTe spectrometer. The absorbed dose is calculated by the Monte Carlo method. The absorbed dose in the water phantom at tube voltage up to 80 kV was 0,9–1,5 mGy.

Ionizing radiation and its considerations in imaging diagnosis: comparison of absorbed dose between cone beam computed tomography and multi-detector computed tomography in the head and neck

2021 ◽  
Author(s):  
P.L.E. Oliveira ◽  
C.R. Starling ◽  
C.L.P. Maurício ◽  
F.R. Guedes ◽  
M.A. Visconti ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Head And Neck ◽  
Cone Beam Computed Tomography ◽  
Absorbed Dose ◽  
Cone Beam ◽  
Thermoluminescent Dosimeters ◽  
Organ Tissue ◽  
The Mean ◽  
Average Adult ◽  
Multi Detector Computed Tomography

Introduction: The objective of this study was to compare the mean absorbed dose in patients undergoing head and neck examinations using two cone beam computed tomography (CBCT, Kodak and i-CAT) and one multi-detector computed tomography (MDCT). Methods: Three thermoluminescent dosimeters (TLDs), calibrated in air kerma, were positioned in 24 regions of the head and neck of a phantom simulating an average adult. The mean absorbed dose (mGy) values in these positions, for different organs and tissues, were obtained using correction factors, considering the ratio between the mass energy absorption coefficients of organ/tissue and air. Comparison between radiation doses in the most radiosensitive regions was done by calculating the ratio of these dose values, with propagated uncertainty. Results: The dose in all regions was significantly higher for MDCT when compared to CBCT. Concerning CBCT equipment, the Kodak device had a higher absorbed dose than the i-CAT for most of the regions tested. The uncertainty of the i-CAT was greater than that of the Kodak. Conclusion: Due to the considerable difference between absorbed doses, emphasizing the higher dose values obtained in MDCT, the dissemination of CBCT application in medicine is recommended, as well as further studies to broaden the criteria for use.

scholarly journals Molecular Mechanisms of Specific Cellular DNA Damage Response and Repair Induced by the Mixed Radiation Field During Boron Neutron Capture Therapy

2021 ◽  
Vol 11 ◽  
Author(s):  
Kamila Maliszewska-Olejniczak ◽  
Damian Kaniowski ◽  
Martyna Araszkiewicz ◽  
Katarzyna Tymińska ◽  
Agnieszka Korgul
Keyword(s):  
Dna Damage ◽  
Radiation Field ◽  
Dna Damage Response ◽  
Boron Neutron Capture Therapy ◽  
Neutron Capture ◽  
Molecular Mechanisms ◽  
Neutron Capture Therapy ◽  
Boron Neutron Capture ◽  
Damage Response ◽  
Mixed Radiation Field

The impact of a mixed neutron-gamma beam on the activation of DNA damage response (DDR) proteins and non-coding RNAs (ncRNAs) is poorly understood. Ionizing radiation is characterized by its biological effectiveness and is related to linear energy transfer (LET). Neutron-gamma mixed beam used in boron neutron capture therapy (BNCT) can induce another type of DNA damage such as clustered DNA or multiple damaged sites, as indicated for high LET particles, such as alpha particles, carbon ions, and protons. We speculate that after exposure to a mixed radiation field, the repair capacity might reduce, leading to unrepaired complex DNA damage for a long period and may promote genome instability and cell death. This review will focus on the poorly studied impact of neutron-gamma mixed beams with an emphasis on DNA damage and molecular mechanisms of repair. In case of BNCT, it is not clear which repair pathway is involved, and recent experimental work will be presented. Further understanding of BNCT-induced DDR mechanisms may lead to improved therapeutic efficiency against different tumors.

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