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Eakins J, Hager L, O'Connor U, Cooke J, O'Reilly G, Walsh C, Willson T. Personal dosimetry for positron emitters, and occupational exposures from clinical use of gallium-68. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2022; 42:031511. [PMID: 35947972 DOI: 10.1088/1361-6498/ac8885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 08/10/2022] [Indexed: 06/15/2023]
Abstract
The current status and issues regarding positron dosimetry in nuclear medicine are summarized. The suitability of the United Kingdom Health Security Agency extremity and eye beta-gamma personal thermoluminescence dosemeters are then considered. Monte Carlo modelling is performed to determine their responses and derive sets of calibration factors, along withHp(0.07) andHp(3) conversion coefficients, for carbon-11, nitrogen-13, oxygen-15, fluorine-18 and gallium-68 sources, which are commonly used in positron emission tomography (PET) computed tomography; data for these isotopes is assumed extrapolatable to other positron sources. It is found that the dosemeters are adequate for assessing exposures to PET radionuclides, even if their routine calibrations to caesium-137 were maintained. An idealized set of measurements representing gallium-68 exposure scenarios is then described, including reproducible mock-ups of individuals manipulating vials and syringes. Finally, a short case-study is presented that explores occupational doses during routine clinical use of gallium-68. The extremity dosemeter results demonstrated significant variations dependent upon the exposure conditions, with some seen to be comparatively large; whole-body and eye dose rates per activity were found to be lower. The importance of routine dose monitoring of workers is emphasized, with the need for a longer-termed follow-up study demonstrated.
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Affiliation(s)
- J Eakins
- United Kingdom Health Security Agency (UKHSA) RCE, Didcot, Oxfordshire, United Kingdom
| | - L Hager
- United Kingdom Health Security Agency (UKHSA) RCE, Didcot, Oxfordshire, United Kingdom
| | - U O'Connor
- Medical Physics & Bioengineering Department, St James's Hospital, Dublin, Ireland
| | - J Cooke
- Medical Physics & Bioengineering Department, St James's Hospital, Dublin, Ireland
| | - G O'Reilly
- Medical Physics & Bioengineering Department, St James's Hospital, Dublin, Ireland
| | - C Walsh
- Medical Physics & Bioengineering Department, St James's Hospital, Dublin, Ireland
| | - T Willson
- Nuclear Medicine Department, Royal Free London NHS Foundation Trust, London, United Kingdom
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Polo IO, Santos WS, Viccari de Moraes C, Nicolucci P. Response of a TLD badge to the new operational quantity Hp(θ): Monte Carlo approach. Radiat Phys Chem Oxf Engl 1993 2022. [DOI: 10.1016/j.radphyschem.2021.109869] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Eakins JS, Tanner RJ. The effects of revised operational dose quantities on the response characteristics of a beta/gamma personal dosemeter. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2019; 39:399-421. [PMID: 30716724 DOI: 10.1088/1361-6498/ab0443] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The International Commission on Radiation Units and Measurements is considering revising the definitions of the operational dose quantities used for personal monitoring. This paper investigates the impacts of the proposed changes on the Public Health England two-element β/γ personal thermoluminescence dosemeter (TLD), in terms of its energy and angle dependences of responses for both skin and whole-body dose assessments. In general, the photon response of the skin element would be unaffected by the proposal, though technical issues may arise during calibration. For body photon doses, the current TLD design still produces acceptable response characteristics in some circumstances, but in general it will need to be redesigned to better match the requirements of the new operational quantity; to that end, a simple adaption is demonstrated that might provide a partial solution. For electron/beta exposures, matching the combined responses of both the body and skin elements to the dose quantities may be more challenging. The performance criteria against which dosemeters are judged may also need to be revised to reflect the proposed change.
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Gilvin PJ, Baker ST, Eakins JS, Tanner RJ. USE OF A SIMPLE THERMALISED NEUTRON FIELD FOR QUALITY ACCEPTANCE OF WHOLE BODY TLDS. RADIATION PROTECTION DOSIMETRY 2016; 170:108-112. [PMID: 26801052 DOI: 10.1093/rpd/ncv545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The individual monitoring service of Public Health England (PHE) uses Harshaw™ whole-body and extremity thermoluminescent dosemeters (TLDs) with high-sensitivity lithium fluoride LiF:Mg,Cu,P, together with Harshaw 8800™ automated readers. The neutron-insensitive, (6)Li-depleted variety of TLD material is used by PHE because the service provides separate neutron and photon dosemeters. The neutron dosemeters are not sensitive to photons and vice versa Since insensitivity to neutrons is a supply requirement for TLDs, there is a need to test every new (annual) consignment for this. Because it is thermal neutrons that produce a response in (6)Li TLDs, a thermal field is needed. To this end, PHE has adopted the simple approach of sandwiching the TLDs between two ISO water-filled slab phantoms. In this arrangement, the fast neutrons from an Am-Be source are effectively thermalised. Details of the method are given, together with the results of supporting MCNP calculations and some typical results.
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Affiliation(s)
- P J Gilvin
- Public Health England, CRCE, Chilton, Didcot, Oxon OX11 0RQ, UK
| | - S T Baker
- Public Health England, CRCE, Chilton, Didcot, Oxon OX11 0RQ, UK
| | - J S Eakins
- Public Health England, CRCE, Chilton, Didcot, Oxon OX11 0RQ, UK
| | - R J Tanner
- Public Health England, CRCE, Chilton, Didcot, Oxon OX11 0RQ, UK
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Ferrari P, Mariotti F, Campani L. EDEL: ENEA DOSEMETER FOR EYE LENS. RADIATION PROTECTION DOSIMETRY 2016; 170:145-149. [PMID: 26170436 DOI: 10.1093/rpd/ncv369] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Since the publication of International Commission on Radiological Protection statement in 2011 on tissue reaction, eye lens radiation protection played an important role in exposed personnel dosimetry. For this reason, the Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA) Individual Monitoring Service decided to study a prototype to fulfil specific requests (e.g. for survey in interventional department and intercomparisons). On the basis of such preliminary investigation, a new eye lens dosemeter was developed. The new dosemeter, named EDEL (ENEA Dosemeter for Eye Lens), was characterised in terms of Hp(3), the operational quantity related to eye lens monitoring. The investigation was performed experimentally and optimised using the Monte Carlo MCNP6 code. The new prototype was thought to fulfil two main requests: the reliability of the dosimetric data and the portability of the dosemeter itself. The new dosemeter will soon be supplied to the collaborating hospitals for workplace test measurements.
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Affiliation(s)
- Paolo Ferrari
- ENEA-Radiation Protection Institute, 4, Via Martiri di Monte Sole, 40129 Bologna, Italy
| | - Francesca Mariotti
- ENEA-Radiation Protection Institute, 4, Via Martiri di Monte Sole, 40129 Bologna, Italy
| | - Lorenzo Campani
- ENEA-Radiation Protection Institute, 4, Via Martiri di Monte Sole, 40129 Bologna, Italy
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Discher M, Hiller M, Woda C. MCNP simulations of a glass display used in a mobile phone as an accident dosimeter. RADIAT MEAS 2015. [DOI: 10.1016/j.radmeas.2015.02.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Otto T, Gindraux L, Strasser M. The thermoluminescence efficiency of Li2B4O7:Cu and of CaSO4:Tm for photons. RADIATION PROTECTION DOSIMETRY 2011; 144:234-238. [PMID: 21183547 DOI: 10.1093/rpd/ncq503] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The intrinsic thermoluminescence (TL) efficiency of a TL detector relates the absorbed dose in the detector material to the light yield observed upon evaluation. Knowledge of the TL efficiency is of interest when performing numerical simulations of detector response, where only absorbed dose can be predicted. Here, the experimental determination of TL efficiency for calcium sulphate (CaSO(4):Tm) and lithium borate (Li(2)B(4)O(7):Cu) is reported. These materials are widely used in Panasonic dosemeter badges. The results of the study are in agreement with predictions from track structure theory and microdosimetry, relating an enhanced light yield at low X-ray energies to supralinear behaviour of the TL phosphor.
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Affiliation(s)
- Th Otto
- Radiation Protection Group, CERN, CH-1211 Genève 23, Switzerland.
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Baker ST, Roberts GH, Gilvin PJ. Evaluating the performance of the Harshaw™ DXTRAD LiF:Mg,Cu,P finger ring with two different thickness filters. RADIATION PROTECTION DOSIMETRY 2011; 144:243-245. [PMID: 21212080 DOI: 10.1093/rpd/ncq564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Amongst the dosemeters offered by the Health Protection Agency (HPA) Personal Dosimetry Service are finger rings, which use the Harshaw™ DXTRAD element. This paper describes restricted-type testing carried out by HPA on the previously untried combination of the LiF:Mg,Cu,P material and a thicker filter (42 mg cm(-2)). The tests were based on ISO 12794 [International Organization for Standardization. ISO 12794:2000 nuclear energy--radiation protection--individual thermoluminescence dosemeters for the extremities and eyes. ISO (2000)] and included energy and angle dependence of response for photons. The conclusion was, for photon dosimetry applications the thicker filter is acceptable for use in the HPA service.
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Affiliation(s)
- S T Baker
- Health Protection Agency, Chilton, Didcot, Oxon OX11 0RQ, UK.
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Gilvin PJ, Burkett RA, Baker ST, Garratt NJ. Long-term stability of Harshaw LiF:Mg,Cu,P TLDS. RADIATION PROTECTION DOSIMETRY 2011; 144:192-194. [PMID: 21216732 DOI: 10.1093/rpd/ncq559] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The sensitivity of Harshaw™ magnesium/copper/phosphorus-doped lithium fluoride is shown to be stable over long time periods, even when, as is often the case in practical operations, the TLDs are read out only three times a year.
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Affiliation(s)
- P J Gilvin
- Health Protection Agency, Chilton, Oxon OX11 0RQ, Didcot, UK.
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Eakins J. On the effect of updated MCNP photon cross section data on the simulated response of the HPA TLD. RADIATION PROTECTION DOSIMETRY 2009; 134:66-71. [PMID: 19386775 DOI: 10.1093/rpd/ncp023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The relative response of the new Health Protection Agency thermoluminescence dosimeter (TLD) has been calculated for Narrow Series X-ray distribution and (137)Cs photon sources using the Monte Carlo code MCNP5, and the results compared with those obtained during its design stage using the predecessor code, MCNP4c2. The results agreed at intermediate energies (approximately 0.1 MeV to (137)Cs), but differed at low energies (<0.1 MeV) by up to approximately 10%. This disparity has been ascribed to differences in the default photon interaction data used by the two codes, and derives ultimately from the effect on absorbed dose of the recent updates to the photoelectric cross sections. The sources of these data have been reviewed.
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Affiliation(s)
- Jonathan Eakins
- Health Protection Agency, Radiation Protection Division, CRCE, Chilton, Didcot, Oxon OX11 0RQ, UK.
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