The study aimed to implement realistic source models of a computed tomography (CT) scanner and Monte Carlo simulations to actual patient data and to calculate patient-specific organ and effective dose estimates for patients undergoing dynamic CT myocardial perfusion examinations. Source models including bowtie filter, tube output and x-ray spectra were determined for a dual-source Siemens Somatom Definition Flash scanner. Twenty CT angiography patient datasets were merged with a scaled International Commission on Radiological Protection (ICRP) 110 voxel phantom. Dose simulations were conducted with ImpactMC software. Effective dose estimates varied from 5.0 to 14.6 mSv for the 80 kV spectrum and from 8.9 to 24.7 mSv for the 100 kV spectrum. Significant differences in organ doses and effective doses between patients emphasise the need to use actual patient data merged with matched anthropomorphic anatomy in the dose simulations to achieve a reasonable level of accuracy in the dose estimation procedure.

Personalized dosimetry in computed tomography (CT) can be realized by a full Monte Carlo (MC) simulation of the scan procedure. Essential input data needed for the simulation are appropriate CT x-ray source models and a model of the patient's body which is based on the CT image. The purpose of this work is to develop comprehensive procedures for the determination of CT x-ray source models and their verification by comparison of calculated and measured dose distributions in physical phantoms. Mobile equipment together with customized software was developed and used for non-invasive determination of equivalent source models of CT scanners under clinical conditions. Standard and physical anthropomorphic CT dose phantoms equipped with real-time CT dose probes at five representative positions were scanned. The accumulated dose was measured during the scan at the five positions. ImpactMC, an MC-based CT dose software program, was used to simulate the scan. The necessary inputs were obtained from the scan parameters, from the equivalent source models and from the material-segmented CT images of the phantoms. 3D dose distributions in the phantoms were simulated and the dose values calculated at the five positions inside the phantom were compared to measured dose values. Initial results were obtained by means of a General Electric Optima CT 660 and a Toshiba (Canon) Aquilion ONE. In general, the measured and calculated dose values were within relative uncertainties that had been estimated to be less than 10%. The procedures developed were found to be viable and rapid. The procedures are applicable to any scanner type under clinical conditions without making use of the service mode with stationary x-ray tube position. Results show that the procedures are well suited for determining and verifying the equivalent source models needed for personalized CT dosimetry based on post-scan MC calculations.

A supplementary comparison has been made between the air-kerma standards of the NRPA (Norway), the STUK (Finland) the SSM (Sweden) and the LNE-LNHB (France) in the ISO 4037 narrow spectrum series in the range 40 kV to 300 kV. The technical protocol was approved by the CCRI(I) in April 2016. The results show the standards to be in agreement at the level of the standard uncertainty of 12, 14 and 8 parts in 10³ for the NRPA, the STUK and the SSM respectively. The results are analysed and presented in terms of degrees of equivalence. KEY WORDS FOR SEARCH Supplementary comparison, air kerma, narrow spectrum series, radiation dosimetry Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

A supplementary comparison has been made between the air-kerma standards of the NRPA, Norway, the STUK, Finland, the SSM, Sweden and the LNE-LNHB, France in the medium-energy x-ray range. The technical protocol was approved by the CCRI(I) in April 2016. The results show the standards to be in agreement at the level of the standard uncertainty of the comparison of 4.4, 9.1 and 4.5 parts in 10³ for the NRPA, STUK and the SSM, respectively. The results are analysed and presented in terms of degrees of equivalence. KEY WORDS FOR SEARCH Supplementary comparison, air kerma, medium energy x-rays, radiation dosimetry Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

A supplementary comparison has been made between the air-kerma standards of the NRPA, Norway, the STUK, Finland, the SSM, Sweden and the LNE-LNHB, France in the low-energy x-ray range, and between the NRPA and the LNE-LNHB in the mammography x-ray range. The technical protocol was approved by the CCRI(I) in April 2016. The results show the standards to be in agreement at the level of the standard uncertainty of the comparison of 6.8, 10.0 and 7.4 parts in 10³ for the NRPA, the STUK and the SSM respectively. For mammography, the standard uncertainty was 5.3 parts in 103 for the NRPA. The results are analysed and presented in terms of degrees of equivalence. KEY WORDS FOR SEARCH Supplementary comparison, air kerma, low energy x-rays, mammography, radiation dosimetry Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

A supplementary comparison has been made between the air-kerma standards of the NRPA (Norway), the STUK (Finland) the SSM (Sweden) and the LNE-LNHB (France) in the ISO 4037 narrow spectrum series in the range 40 kV to 300 kV. The technical protocol was approved by the CCRI(I) in April 2016. The results show the standards to be in agreement at the level of the standard uncertainty of 12, 14 and 8 parts in 10(3) for the NRPA, the STUK and the SSM respectively. The results are analysed and presented in terms of degrees of equivalence.

Introduction: The development of advanced radiotherapy techniques, such as dynamic IMRT and Volumetric Arc Therapy increases the need for accurate and traceable measurement of complex dose distributions to validate TPS dose calculations. The aim of WP 6 is to develop, validate, compare and characterize anthropomorphic phantom based measurement methods for the 2D/3D verification of the treatment planning system for photon and for some methods in electron beams as well.

The EURAMET #1177 project, identified as EURAMET RI(I) - S9 comparison, was the first EURAMET wide scale supplementary comparison in the field of diagnostic radiology for air kerma area product, PKA, and air kerma, K. It was conducted with the goal of testing the measurement and calibration capabilities for PKA and K, as well as of supporting the relevant CMCs of the participating laboratories. Two commercial KAP meters and an ionization chamber were selected as transfer instruments and circulated between the 22 European participants. The measurements were performed from April 2011 until July 2012. The stability and the performance of the transfer instruments were tested by the pilot laboratory (IRCL/GAEC-EIM) and few other laboratories as well. The test results revealed that the energy (radiation quality), Q, irradiation area, A, and air kerma rate, K̇ dependences of response of the transfer KAP meters influence the comparison of the results when different measurement conditions were pertained and therefore, appropriate correction factors were obtained and applied to the reported calibration results of the laboratories, when necessary. The comparison reference values (CRVs) for each instrument were determined as the weighted mean of the calibration coefficients of the three participating primary laboratories. The relative standard uncertainty of the CRVs were in the range of (0.4 - 1.6)% depending on the transfer instruments and beam qualities. The comparison result as the ratio of the corrected calibration coefficient of participant and the respective CRV, and its uncertainty were calculated for all beam qualities and transfer instruments. The informative degrees of equivalence (DoE) were calculated for the refrence RQR 5 beam quality. In case of air kema area product measurements the results for the RADCAL PDC KAP meter were used. The 216 KAP meter calibration results of the two different transfer instruments in terms of air kerma area product were consistent within 5% except 40 results of 8 participants. The 103 air kerma calibration results were consistent within 1.7%, except 10 results of 4 participants. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Introduction: Gafchromic™ EBT3 film was used to verify the dose calculations for mixed electron and photon beams in water phantom. Film was irradiated and read after a fixed time period with a flatbed scanner (Epson Perfection V750-M Pro), converted to dose and compared to the calculations. Clinically acceptable accuracy was achieved, following described procedures. Accuracy was improved by scanning the film in four different orientations.

Cette publication traite des avancees effectuees pendant le cours du projet HLT09 subventionne par EMRP (European Metrology Research Program). Ce projet avait pour object if global d’ameliorer la tracabilite, a des references nationales, de la dose absorbee delivree a la tumeur dans la cadre d’un traitement par radiotherapie. Les recherches couvrent l’etablissement de references absolues en termes de dose absorbee dans l’eau pour les photons d’energie moyenne, la mise en œuvre du concept de produit dose surface dans la cadre de l’utilisation des faisceaux de photons de haute energie, la caracterisation des faisceaux produit par de nouveaux generateurs de rayons X pour la therapie de contact incluant les etalon primaire et de transfert, l’etude des caracteristiques des detecteurs ponctuels, 2D et 3D en tant qu’etalon de transfert et moyen de controle des plans de traitement.

Pencil-type air-kerma length product meters are generally used for quality control and radiation exposure measurements in computed tomography. To ensure reliable results, these meters should be calibrated so that measurements are traceable to international standards. Suitable calibration procedures, together with the properties of these meters, were examined and compared with the international standards and recommendations. The calibration procedure and setup used in this study were slightly modified compared with international recommendations. The special collimator system was found to cause less scatter than similar setups in earlier studies. The energy dependence of the meter response was investigated for several types of meters with standard radiation qualities. With most tested meter types, the total variation due to energy dependence was <4 %, but some had strong energy dependence and the variation was up to 15 % or higher. This highlights the importance of a proper calibration. The response of one semiconductor meter type varied up to 8 % when rotating the meter around its axis; this should be taken into account when making calibrations with a static setup.

Magnesium-walled argon gas flow ionization chamber (Mg(Ar)) is used for photon dose measurements in the epithermal neutron beam of FiR 1 reactor in Finland. In this study, the photon dose measurements were re-evaluated against calculations applying a new chamber calibration factor defined in water instead of in air. Also, effect of the build-up cap on the measurements was investigated. The new calibration factor provides improved agreement between measured and calculated photon dose. Use of the build-up cap does not affect the measured signal in water in neutron beam.