1
|
Bonvin V, Bochud F, Theis C, Vincke H, Damet J, Geyer R. A combined approach for the calculation of activation yields and the characterization of materials for a medical cyclotron. Appl Radiat Isot 2024; 204:111116. [PMID: 38091906 DOI: 10.1016/j.apradiso.2023.111116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 10/31/2023] [Accepted: 11/18/2023] [Indexed: 12/31/2023]
Abstract
Cyclotrons for the production of radiopharmaceuticals have become important tools in modern nuclear medicine. At the end of their lifecycles, such installations have to be dismantled and any activated materials must be treated according to the local radiation protection legislation. Using a simulation model, we have developed a non-destructive approach for the radiological characterization of components inside and around an IBA Cyclone 18/9 cyclotron. The methodology is based on software tools developed at CERN (FLUKA Monte Carlo code, ActiWiz and RAW). The simulation results were compared to measurements made using reference samples placed around the cyclotron inside the bunker. Results show a reasonable agreement between simulation and measurements of about a factor of two for a set of 27 reference samples and 11 radionuclides of interest. The origin of this factor has been thoroughly evaluated and opened the door to further investigations leading to possible avenues for improvement.
Collapse
Affiliation(s)
- V Bonvin
- European Council for Nuclear Research (CERN), Esplanade des Particules, CH-1211, Meyrin, Switzerland; Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, Rue Du Grand-Pré 1, CH-1007, Lausanne, Switzerland.
| | - F Bochud
- Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, Rue Du Grand-Pré 1, CH-1007, Lausanne, Switzerland
| | - C Theis
- European Council for Nuclear Research (CERN), Esplanade des Particules, CH-1211, Meyrin, Switzerland
| | - H Vincke
- European Council for Nuclear Research (CERN), Esplanade des Particules, CH-1211, Meyrin, Switzerland; University of Technology, Rechbauerstraße 12, 8010, Graz, Austria
| | - J Damet
- Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, Rue Du Grand-Pré 1, CH-1007, Lausanne, Switzerland; University of Otago, 2 Riccarton Ave, Christchurch, New Zealand
| | - R Geyer
- European Council for Nuclear Research (CERN), Esplanade des Particules, CH-1211, Meyrin, Switzerland; Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, Rue Du Grand-Pré 1, CH-1007, Lausanne, Switzerland
| |
Collapse
|
2
|
Monnin P, Damet J, Bosmans H, Marshall NW. Task-based detectability in anatomical background in digital mammography, digital breast tomosynthesis and synthetic mammography. Phys Med Biol 2024; 69:025017. [PMID: 38214048 DOI: 10.1088/1361-6560/ad1766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 12/20/2023] [Indexed: 01/13/2024]
Abstract
Objective.Determining the detectability of targets for the different imaging modalities in mammography in the presence of anatomical background noise is challenging. This work proposes a method to compare the image quality and detectability of targets in digital mammography (DM), digital breast tomosynthesis (DBT) and synthetic mammography.Approach. The low-frequency structured noise produced by a water phantom with acrylic spheres was used to simulate anatomical background noise for the different types of images. A method was developed to apply the non-prewhitening observer model with eye filter (NPWE) in these conditions. A homogeneous poly(methyl) methacrylate phantom with a 0.2 mm thick aluminium disc was used to calculate 2D in-plane modulation transfer function (MTF), noise power spectrum (NPS), noise equivalent quanta, and system detective quantum efficiency for 30, 50 and 70 mm thicknesses. The in-depth MTFs of DBT volumes were determined using a thin tungsten wire. The MTF, system NPS and anatomical NPS were used in the NPWE model to calculate the threshold gold thickness of the gold discs contained in the CDMAM phantom, which was taken as reference. Main results.The correspondence between the NPWE model and the CDMAM phantom (linear Pearson correlation 0.980) yielded a threshold detectability index that was used to determine the threshold diameter of spherical microcalcifications and masses. DBT imaging improved the detection of masses, which depended mostly on the reduction of anatomical background noise. Conversely, DM images yielded the best detection of microcalcifications.Significance.The method presented in this study was able to quantify image quality and object detectability for the different imaging modalities and levels of anatomical background noise.
Collapse
Affiliation(s)
- P Monnin
- Institute of radiation physics (IRA), Lausanne University Hospital (CHUV) and University of Lausanne, Rue du Grand-Pré 1, 1007 Lausanne, Switzerland
| | - J Damet
- Institute of radiation physics (IRA), Lausanne University Hospital (CHUV) and University of Lausanne, Rue du Grand-Pré 1, 1007 Lausanne, Switzerland
| | - H Bosmans
- UZ Gasthuisberg, Department of Radiology, Herestraat 49, 3000 Leuven, Belgium
- Medical Imaging Research Center, Medical Physics and Quality Assessment, Katholieke Universiteit Leuven, 3000 Leuven, Belgium
| | - N W Marshall
- UZ Gasthuisberg, Department of Radiology, Herestraat 49, 3000 Leuven, Belgium
- Medical Imaging Research Center, Medical Physics and Quality Assessment, Katholieke Universiteit Leuven, 3000 Leuven, Belgium
| |
Collapse
|
3
|
Gallego Manzano L, Monnin P, Sayous Y, Becce F, Damet J, Viry A. Clinical commissioning of the first point-of-care spectral photon-counting CT for the upper extremities. Med Phys 2023; 50:2844-2859. [PMID: 36807109 DOI: 10.1002/mp.16313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Revised: 01/14/2023] [Accepted: 01/15/2023] [Indexed: 02/23/2023] Open
Abstract
BACKGROUND Acceptance testing and quality assurance (QA) of computed tomography (CT) scans are of great importance to ensure the appropriate performance of the systems. However, current standards and guidelines do not include a dedicated QA program for spectral photon-counting CT (SPCCT), nor adapted tolerance levels. PURPOSE To evaluate the technical performance, in terms of image quality and radiation dose, of the first point-of-care SPCCT for the upper extremities (MARS Extremity 5X120, MARS Bioimaging Ltd., Christchurch, New Zealand) and to establish a comprehensive QA program. METHODS The specific dimensions of the scanner with a 125 mm diameter gantry and a small voxel size of 0.1 × 0.1 × 0.1 mm3 require the use of suitable phantoms and evaluation techniques. Indicators such as CT number accuracy, image noise, uniformity, and slice thickness were assessed to characterize the image quality. The in-plane and longitudinal spatial resolutions were evaluated by means of the modulation transfer function (MTF). Noise power spectra (NPS) were calculated to further evaluate the image noise. Material identification capabilities were assessed using clinically relevant high-Z materials (iodine, gold, gadolinium, and calcium). A 100-mm diameter CTDI-like phantom was used to measure the dose indices. A complete radiation survey was carried out to measure the radiation exposure at different points around the scanner. RESULTS The proposed QA program is based on international and local recommendations as well as practical experience. It includes standardised CT tests and SPCCT-specific methods. Additional methodologies to further assess the system performance are also presented. Tolerance levels are discussed and revised when appropriate. Both in-plane and longitudinal high spatial resolutions were evidenced by the MTF measurements with 1.8 lp· mm-1 and 5.0 lp· mm-1 at 10%, respectively. The calculated effective slice thickness ranged between 0.15 and 0.16 mm for the five energy bins and for a reconstructed voxel size of 0.1 × 0.1 × 0.1 mm3 . Reference values of the linear attenuation coefficient of water have been calculated and used to assess the CT number uniformity of water. Evaluation of the CT number accuracy and stability of various clinically relevant materials showed excellent spectral correlation and linearity between HU values and concentrations (r2 > 0.99). The NPS showed less noise correlation between slices than within transverse slice, as well as a systematic increase at low spatial frequencies. The volume CT dose index (CTDI v o l $_{vol}$ ) for a custom-made 100 mm diameter phantom was 9.32 mGy. Radiation measurements around the scanner showed that it is completely shielded except for the access port, and that no additional protective measures are necessary for the patient. CONCLUSIONS A routine QA framework for SPCCT systems has been proposed. Image quality and radiation dose were assessed using newly designed phantoms, relevant metrics, and automated algorithms. Baseline values were established and tolerance levels discussed for the MARS SPCCT scanner based on collected data and international recommendations.
Collapse
Affiliation(s)
- Lucía Gallego Manzano
- Institute of Radiation Physics (IRA), Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland
| | - Pascal Monnin
- Institute of Radiation Physics (IRA), Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland
| | - Yann Sayous
- MARS Bioimaging Ltd., Christchurch, New Zealand.,University of Canterbury, Christchurch, New Zealand
| | - Fabio Becce
- Department of Diagnostic and Interventional Radiology, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland
| | - Jérôme Damet
- Institute of Radiation Physics (IRA), Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland.,University of Otago, Christchurch, New Zealand
| | - Anaïs Viry
- Institute of Radiation Physics (IRA), Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland
| |
Collapse
|
4
|
Manzano LG, Monnin MP, Sayous MY, Becce F, Damet J, Viry A. CLINICAL COMMISSIONING OF THE FIRST POINT-OF-CARE SPECTRAL PHOTON-COUNTING CT FOR THE UPPER EXTREMITIES. Phys Med 2022. [DOI: 10.1016/s1120-1797(22)02248-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
|
5
|
Monnin P, Viry A, Damet J, Nowak M, Vitzthum V, Racine D. A novel method to assess the spatiotemporal image quality in fluoroscopy. Phys Med Biol 2021; 66. [PMID: 34808602 DOI: 10.1088/1361-6560/ac3c15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 11/22/2021] [Indexed: 11/11/2022]
Abstract
Objectives. The planar formulation of the noise equivalent quanta (NEQ) and detective quantum efficiency (DQE) used to assess the image quality of projection images does not deal with the influence of temporal resolution on signal blurring and image noise. These metrics require correction factors based on temporal resolution when used for dynamic imaging systems such as fluoroscopy. Additionally, the standard NEQ and detector DQE are determined on pre-processed images in scatter-free conditions for effective energies produced by additional aluminium or copper filters that are not representative of clinical fluoroscopic procedures. In this work, we developed a method to measure 'frame NEQ' and 'frame system DQE' which include the temporal frequency bandwidth and consider the anti-scatter grid, the detector and the image processing procedures for beam qualities with scatter fractions representative of clinical use.Approach. We used a solid water phantom to simulate a patient and a thin copper disc to measure the spatial resolution. The copper disc, set in uniform rectilinear motion in the image plane, assessed the temporal resolution. These new metrics were tested on two fluoroscopy systems, a C-arm and a floor-mounted cardiology, for multiple parameters: phantom thicknesses from 5 to 20 cm, frame rates from 3 to 30 fps, spatial and temporal image processing of different weights.Main results.The frame NEQ correctly described the image quality for different scatter conditions, temporal resolutions and image processing techniques. The frame system DQE varied between 0.38 and 0.65 within the different beam and scatter conditions, and correctly mitigated the influence of spatial and temporal image processing.Significance.This study introduces and validates an unbiased formulation of in-plane NEQ and system DQE to assess the spatiotemporal image quality of fluoroscopy systems.
Collapse
Affiliation(s)
- P Monnin
- Institute of radiation physics (IRA), Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Rue du Grand-Pré 1, 1007 Lausanne, Switzerland
| | - A Viry
- Institute of radiation physics (IRA), Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Rue du Grand-Pré 1, 1007 Lausanne, Switzerland
| | - J Damet
- Institute of radiation physics (IRA), Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Rue du Grand-Pré 1, 1007 Lausanne, Switzerland.,University of Otago, Christchurch, New Zealand
| | - M Nowak
- Institute of radiation physics (IRA), Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Rue du Grand-Pré 1, 1007 Lausanne, Switzerland
| | - V Vitzthum
- Institute of radiation physics (IRA), Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Rue du Grand-Pré 1, 1007 Lausanne, Switzerland
| | - D Racine
- Institute of radiation physics (IRA), Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Rue du Grand-Pré 1, 1007 Lausanne, Switzerland
| |
Collapse
|
6
|
Bonvin V, Bochud F, Damet J, Theis C, Vincke H, Geyer R. Detailed study of the distribution of activation inside the magnet coils of a compact PET cyclotron. Appl Radiat Isot 2020; 168:109446. [PMID: 33358068 DOI: 10.1016/j.apradiso.2020.109446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 09/22/2020] [Accepted: 09/24/2020] [Indexed: 11/16/2022]
Abstract
We determined the distribution of activation products inside the magnet coils of a medical cyclotron that has been operational for fifteen years. Besides FLUKA, we based our approach on new software tools (RAW and ActiWiz) developed for high-energy accelerators at CERN. A combined analysis of measurements on the coils with Monte-Carlo simulations resulted in a detailed three-dimensional radiological characterisation of the coils. Our results provide the required information for the radiation protection expert to identify the appropriate waste elimination scheme.
Collapse
Affiliation(s)
- V Bonvin
- European Council for Nuclear Research (CERN), Esplanade des Particules, CH-1211, Meyrin, Switzerland; Institute for Radiation Physics, Lausanne University Hospital, Rue du Grand-Pré, CH-1007, Lausanne, Switzerland.
| | - F Bochud
- Institute for Radiation Physics, Lausanne University Hospital, Rue du Grand-Pré, CH-1007, Lausanne, Switzerland
| | - J Damet
- Institute for Radiation Physics, Lausanne University Hospital, Rue du Grand-Pré, CH-1007, Lausanne, Switzerland; University of Otago, 2 Riccarton Ave, Christchurch, New Zealand
| | - C Theis
- European Council for Nuclear Research (CERN), Esplanade des Particules, CH-1211, Meyrin, Switzerland
| | - H Vincke
- European Council for Nuclear Research (CERN), Esplanade des Particules, CH-1211, Meyrin, Switzerland; University of Technology, Rechbauerstraße 12, 8010, Graz, Austria
| | - R Geyer
- European Council for Nuclear Research (CERN), Esplanade des Particules, CH-1211, Meyrin, Switzerland; Institute for Radiation Physics, Lausanne University Hospital, Rue du Grand-Pré, CH-1007, Lausanne, Switzerland
| |
Collapse
|
7
|
Medici S, Desorgher L, Carbonez P, Damet J, Bochud F, Pitzschke A. Impact of the phantom geometry on the evaluation of the minimum detectable activity following a radionuclide intake: From physical to numerical phantoms. RADIAT MEAS 2020. [DOI: 10.1016/j.radmeas.2020.106485] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
8
|
Nowak M, Carbonez P, Krauss M, Verdun FR, Damet J. Characterisation and mapping of scattered radiation fields in interventional radiology theatres. Sci Rep 2020; 10:18754. [PMID: 33127938 PMCID: PMC7599331 DOI: 10.1038/s41598-020-75257-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 09/30/2020] [Indexed: 12/02/2022] Open
Abstract
We used the Timepix3 hybrid pixel detector technology in order to determine the exposure of medical personnel to ionizing radiation in an interventional radiology room. We measured the energy spectra of the scattered radiation generated by the patient during X-ray image-guided interventional procedures. We performed measurements at different positions and heights within the theatre. We first observed a difference in fluence for each staff member. As expected, we found that the person closest to the X-ray tube is the most exposed while the least exposed staff member is positioned at the patient’s feet. Additionally, we observed a shift in energy from head to toe for practitioners, clearly indicating a non-homogenous energy exposure. The photon counting Timepix3 detector provides a new tool for radiation field characterisation that is easier-to-use and more compact than conventional X-ray spectrometers. The spectral information is particularly valuable for optimising the use of radiation protection gear and improving dosimetry surveillance programs. We also found the device very useful for training purposes to provide awareness and understanding about radiation protection principles among interventional radiology staff.
Collapse
Affiliation(s)
- M Nowak
- CERN, European Organization for Nuclear Research, Geneva, Switzerland. .,Institut of Radiation Physics, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.
| | - P Carbonez
- CERN, European Organization for Nuclear Research, Geneva, Switzerland.,Department of Radiology, University of Otago, Christchurch, New Zealand
| | - M Krauss
- Department of Radiology, University of Otago, Christchurch, New Zealand.,Department of Interventional Radiology, Christchurch Hospital, Christchurch, New Zealand
| | - F R Verdun
- Institut of Radiation Physics, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - J Damet
- CERN, European Organization for Nuclear Research, Geneva, Switzerland.,Institut of Radiation Physics, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.,Department of Radiology, University of Otago, Christchurch, New Zealand
| |
Collapse
|
9
|
Lemesre C, Graf D, Bisch L, Carroz P, Cherbuin N, Damet J, Desorgher L, Siklody CH, Le Bloa M, Pascale P, Pruvot E. Efficiency of the RADPAD Surgical Cap in Reducing Brain Exposure During Pacemaker and Defibrillator Implantation. JACC Clin Electrophysiol 2020; 7:161-170. [PMID: 33602396 DOI: 10.1016/j.jacep.2020.08.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 07/15/2020] [Accepted: 08/03/2020] [Indexed: 11/17/2022]
Abstract
OBJECTIVES This study sought to investigate the RADPAD No Brainer (Worldwide Innovation and Technologies, Overland Park, Kansas) efficiency in reducing brain exposure to scattered radiation. BACKGROUND Cranial radioprotective caps such as the RADPAD No Brainer are being marketed as devices that significantly reduce operator's brain exposure to scattered radiation. However, the efficiency of the RADPAD No Brainer in reducing brain exposure in clinical practice remains unknown to date. METHODS Five electrophysiologists performing device implantations over a 2-month period wore the RADPAD cap with 2 strips of 11 thermoluminescent dosimeter pellets covering the front head above and under the shielded cap. Phantom measurements and Monte Carlo simulations were performed to further investigate brain dose distribution. RESULTS Our study showed that the right half of the operators' front head was the most exposed region during left subpectoral device implantation; the RADPAD cap attenuated the skin front-head exposure but provided no protection to the brain. The exposure of the anterior part of the brain was decreased by a factor of 4.5 compared with the front-head skin value thanks to the skull. The RADPAD cap worn as a protruding horizontal plane, however, reduced brain exposure by a factor of 1.7 (interquartile range: 1.3 to 1.9). CONCLUSIONS During device implantation, the RADPAD No Brainer decreased the skin front head exposure but had no impact on brain dose distribution. The RADPAD No Brainer worn as a horizontal plane worn around the neck reduces brain exposure and confirms that the exposure comes from upward scattered radiation.
Collapse
Affiliation(s)
- Camille Lemesre
- Institute for Radiation Physics, University Hospital Centre Vaudois, Lausanne, Switzerland
| | - Denis Graf
- Department of Cardiology, University Hospital Centre Vaudois, Lausanne, Switzerland
| | | | - Patrice Carroz
- Department of Cardiology, University Hospital Centre Vaudois, Lausanne, Switzerland
| | - Nicolas Cherbuin
- Institute for Radiation Physics, University Hospital Centre Vaudois, Lausanne, Switzerland
| | - Jérôme Damet
- Institute for Radiation Physics, University Hospital Centre Vaudois, Lausanne, Switzerland; Department of Radiology, University of Otago, Christchurch, New Zealand
| | - Laurent Desorgher
- Institute for Radiation Physics, University Hospital Centre Vaudois, Lausanne, Switzerland
| | | | - Mathieu Le Bloa
- Department of Cardiology, University Hospital Centre Vaudois, Lausanne, Switzerland
| | - Patrizio Pascale
- Department of Cardiology, University Hospital Centre Vaudois, Lausanne, Switzerland
| | - Etienne Pruvot
- Department of Cardiology, University Hospital Centre Vaudois, Lausanne, Switzerland.
| |
Collapse
|
10
|
Medici S, Carbonez P, Damet J, Bochud F, Pitzschke A. Use of portable gamma spectrometers for triage monitoring following the intake of conventional and novel radionuclides. RADIAT MEAS 2020. [DOI: 10.1016/j.radmeas.2020.106426] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
11
|
Medici S, Carbonez P, Damet J, Bochud F, Bailat C, Pitzschke A. Detecting intake of radionuclides: In vivo screening measurements with conventional radiation protection instruments. RADIAT MEAS 2019. [DOI: 10.1016/j.radmeas.2019.01.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
12
|
Medici S, Desorgher L, Carbonez P, Damet J, Bochud F, Pitzschke A. In vivo screening measurements with common radiation protection instruments. BIO Web Conf 2019. [DOI: 10.1051/bioconf/20191403003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
13
|
Abstract
PURPOSE Exposure to ionizing radiation is a concern for children during intraoperative imaging. We aimed to assess the radiation exposure to the paediatric patient with 2D and 3D imaging. METHODS To evaluate the radiation exposure, patient absorbed doses to the organs were measured in an anthropomorphic phantom representing a five-year-old child, using thermoluminescent dosimeters. For comparative purposes, organ doses were measured using a C-arm for one minute of fluoroscopy and one acquisition with an O-arm. The cone-beam was centred on the pelvis. Direct and scattered irradiations were measured and compared (Student's t-test). Skin entrance dose rates were also evaluated. RESULTS All radiation doses were expressed in µGy. Direct radiation doses of pelvic organs were between 631.22 and 1691.87 for the O-arm and between 214.08 and 737.51 for the C-arm, and were not significant (p = 0.07). Close scattered radiation on abdominal organs were between 25.11 and 114.85 for the O-arm and between 8.03 and 55.34 for the C-arm, and were not significant (p = 0.07). Far scattered radiation doses on thorax, neck and head varied from 0.86 to 6.42 for the O-arm and from 0.04 to 3.08 for the C-arm, and were significant (p = 0.02). The dose rate at the skin entrance was 328.58 µGy.s-1 for the O-arm and 1.90 with the C-arm. CONCLUSION During imaging of the pelvis, absorbed doses for a 3D O-arm acquisition were higher than with one minute fluoroscopy with the C-arm. Further clinical studies comparing effective doses are needed to assess ionizing risks of the intraoperative imaging systems in children.
Collapse
Affiliation(s)
- M. Prod’homme
- Medical University of Geneva, Geneva, Switzerland,Paediatric Orthopaedic Division, Geneva University Hospital (HUG), Geneva, Switzerland, Correspondence should be sent to M. Prod’homme, Paediatric Orthopaedic Division, Geneva University Hospital (HUG), Rue Willy-Donzé 6, CH-1211 Geneva, Switzerland. E-mail:
| | - M. Sans-Merce
- Radiology Division, Geneva University Hospital (HUG), Geneva, Switzerland,Institute of Radiation Physics, Lausanne University Hospital, Lausanne, Switzerland
| | - N. Pitteloud
- Institute of Radiation Physics, Lausanne University Hospital, Lausanne, Switzerland,Physics Section, University of Geneva, Geneva, Switzerland
| | - J. Damet
- Institute of Radiation Physics, Lausanne University Hospital, Lausanne, Switzerland,Department of Radiology, University of Otago, Christchurch, New Zealand
| | - P. Lascombes
- Medical University of Geneva, Geneva, Switzerland,Paediatric Orthopaedic Division, Geneva University Hospital (HUG), Geneva, Switzerland
| |
Collapse
|
14
|
Merce MS, Pitteloud N, Damet J, Gamulin A, Lascombes P, Prod’homme M. [OA195] Dosimetric evaluation of the O-arm® imaging system. Phys Med 2018. [DOI: 10.1016/j.ejmp.2018.06.267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
|
15
|
Mayer S, Baechler S, Damet J, Elmiger R, Frei D, Giannini S, Leupin A, Sarott F, Schuh R. OCCUPATIONAL EXPOSURE TO EXTERNAL RADIATION IN SWITZERLAND. Radiat Prot Dosimetry 2016; 170:433-436. [PMID: 27012882 DOI: 10.1093/rpd/ncw048] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Individual monitoring for both external and internal exposures is well regulated in Switzerland. The article gives an overview on the occupational exposure to external radiation of workers based on the data collected in the Swiss national dose registry (NDR) in 2013. The NDR records the monthly doses of radiation workers since the introduction of ICRP 60 recommendations and is manifested in the Swiss ordinance since 1994. Annual dose limits for effective dose are typically exceeded once a year in Switzerland, mostly in medicine. The NDR is a useful optimisation tool to identify and characterise areas with the highest exposures. While exceeded dose limits were often related to accidental acute exposure in the past, they are now more related to continuous exposure during normal work, especially in medicine.
Collapse
Affiliation(s)
- S Mayer
- Paul Scherrer Institute, Villigen PSI, Switzerland
| | - S Baechler
- Federal Office of Public Health, Bern, Switzerland
| | - J Damet
- Institute of Radiation Physics, Lausanne University Hospital, Lausanne, Switzerland
| | - R Elmiger
- Federal Office of Public Health, Bern, Switzerland
| | - D Frei
- Federal Office of Public Health, Bern, Switzerland
| | - S Giannini
- Swiss National Accident Insurance Fund, Luzern, Switzerland
| | - A Leupin
- Swiss Federal Nuclear Safety Inspectorate, Brugg, Switzerland
| | - F Sarott
- Leibstadt Nuclear Power Plant, Leibstadt, Switzerland
| | - R Schuh
- Mühleberg Nuclear Power Plant, Mühleberg, Switzerland
| |
Collapse
|
16
|
Sans-Merce M, Damet J, Becker M. Comparative patient organ dose levels for maxillofacial examinations performed with different radiological facilities. Phys Med 2016. [DOI: 10.1016/j.ejmp.2016.07.686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
|
17
|
Kropat G, Baechler S, Bailat C, Barazza F, Bochud F, Damet J, Meyer N, Palacios Gruson M, Butterweck G. Calibration of the Politrack® system based on CR39 solid-state nuclear track detectors for passive indoor radon concentration measurements. Radiat Prot Dosimetry 2015; 167:302-305. [PMID: 25948829 DOI: 10.1093/rpd/ncv267] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Swiss national requirements for measuring radon gas exposures demand a lower detection limit of 50 kBq h m(-3), representing the Swiss concentration average of 70 Bq m(-3) over a 1-month period. A solid-state nuclear track detector (SSNTD) system (Politrack, Mi.am s.r.l., Italy) has been acquired to fulfil these requirements. This work was aimed at the calibration of the Politrack system with traceability to international standards and the development of a procedure to check the stability of the system. A total of 275 SSNTDs was exposed to 11 different radon exposures in the radon chamber of the Secondary Calibration Laboratory at the Paul Scherrer Institute, Switzerland. The exposures ranged from 50 to 15000 kBq h m(-3). For each exposure of 20 detectors, 5 SSNTDs were used to monitor possible background exposures during transport and storage. The response curve and the calibration factor of the whole system were determined using a Monte Carlo fitting procedure. A device to produce CR39 samples with a reference number of tracks using a (241)Am source was developed for checking the long-term stability of the Politrack system. The characteristic limits for the detection of a possible system drift were determined following ISO Standard 11929.
Collapse
Affiliation(s)
- G Kropat
- Institute of Radiation Physics, Lausanne, Switzerland
| | - S Baechler
- Swiss Federal Office of Public Health, Berne, Switzerland
| | - C Bailat
- Institute of Radiation Physics, Lausanne, Switzerland
| | - F Barazza
- Swiss Federal Office of Public Health, Berne, Switzerland
| | - F Bochud
- Institute of Radiation Physics, Lausanne, Switzerland
| | - J Damet
- Institute of Radiation Physics, Lausanne, Switzerland
| | - N Meyer
- Institute of Radiation Physics, Lausanne, Switzerland
| | | | | |
Collapse
|
18
|
Sans Merce M, Korchi AM, Kobzeva L, Damet J, Erceg G, Marcos Gonzalez A, Lovblad KO, Mendes Pereira V. The value of protective head cap and glasses in neurointerventional radiology. J Neurointerv Surg 2015; 8:736-40. [DOI: 10.1136/neurintsurg-2015-011703] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 05/24/2015] [Indexed: 11/04/2022]
Abstract
BackgroundProtection of the head and eyes of the neurointerventional radiologist is a growing concern, especially after recent reports on the incidence of brain cancer among these personnel, and the revision of dose limits to the eye lens. The goal of this study was to determine typical occupational dose levels and to evaluate the efficiency of non-routine radiation protective gear (protective eyewear and cap). Experimental correlations between the dosimetric records of each measurement point and kerma area product (KAP), and between whole body doses and eye lens doses were investigated.MethodsMeasurements were taken using thermoluminescent dosimeters placed in plastic bags and worn by the staff at different places. To evaluate the effective dose, whole body dosimeters (over and under the lead apron) were used.ResultsThe mean annual effective dose was estimated at 0.4 mSv. Annual eye lens exposure was estimated at 17 mSv when using a ceiling shield but without protective glasses. The protective glasses reduced the eye lens dose by a factor of 2.73. The mean annual dose to the brain was 12 mSv; no major reduction was observed when using the cap. The higher correlation coefficients with KAP were found for the dosimeters positioned between the eyes (R2=0.84) and above the apron, and between the eye lens (R2=0.85) and the whole body.ConclusionsUnder the specific conditions of this study, the limits currently applicable were respected. If a new eye lens dose limit is introduced, our results indicate it could be difficult to comply with, without introducing additional protective eyewear.
Collapse
|
19
|
Damet J, Fournier P, Monnin P, Sans-Merce M, Ceroni D, Zand T, Verdun FR, Baechler S. Occupational and patient exposure as well as image quality for full spine examinations with the EOS imaging system. Med Phys 2014; 41:063901. [DOI: 10.1118/1.4873333] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
20
|
Abstract
Monte Carlo simulations were carried out to study the response of a thyroid monitor for measuring intake activities of (125)I and (131)I. The aim of the study was 3-fold: to cross-validate the Monte Carlo simulation programs, to study the response of the detector using different phantoms and to study the effects of anatomical variations. Simulations were performed using the Swiss reference phantom and several voxelised phantoms. Determining the position of the thyroid is crucial for an accurate determination of radiological risks. The detector response using the Swiss reference phantom was in fairly good agreement with the response obtained using adult voxelised phantoms for (131)I, but should be revised for a better calibration for (125)I and for any measurements taken on paediatric patients.
Collapse
Affiliation(s)
- J Damet
- University Institute for Radiation Physics, University Hospital of Lausanne, 1007 Lausanne, Switzerland.
| | | | | | | | | |
Collapse
|
21
|
Damet J, Sans-Merce M, Miéville F, Becker M, Poletti PA, Verdun FR, Baechler S. Comparison of organ doses and image quality between CT and flat panel XperCT scans in wrist and inner ear examinations. Radiat Prot Dosimetry 2010; 139:164-168. [PMID: 20200104 DOI: 10.1093/rpd/ncq062] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The aim of this study was to evaluate and compare organ doses delivered to patients in wrist and petrous bone examinations using a multislice spiral computed tomography (CT) and a C-arm cone-beam CT equipped with a flat-panel detector (XperCT). For this purpose, doses to the target organ, i.e. wrist or petrous bone, together with those to the most radiosensitive nearby organs, i.e. thyroid and eye lens, were measured and compared. Furthermore, image quality was compared for both imaging systems and different acquisition modes using a Catphan phantom. Results show that both systems guarantee adequate accuracy for diagnostic purposes for wrist and petrous bone examinations. Compared with the CT scanner, the XperCT system slightly reduces the dose to target organs and shortens the overall duration of the wrist examination. In addition, using the XperCT enables a reduction of the dose to the eye lens during head scans (skull base and ear examinations).
Collapse
Affiliation(s)
- J Damet
- Institute of Radiation Physics, University Hospital Center and University of Lausanne, Grand Pré 1, 1007 Lausanne, Switzerland.
| | | | | | | | | | | | | |
Collapse
|