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Chiriotti S, Parisi A, Vanhavere F, De Saint-Hubert M, Vandevoorde C, Slabbert J, Beukes P, de Kock E, Symons J. MICRODOSIMETRIC MEASUREMENT OF SECONDARY RADIATION IN THE PASSIVE SCATTERED PROTON THERAPY ROOM OF iTHEMBA LABS USING A TISSUE-EQUIVALENT PROPORTIONAL COUNTER. Radiat Prot Dosimetry 2018; 182:252-257. [PMID: 29669096 DOI: 10.1093/rpd/ncy056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2018] [Accepted: 03/22/2018] [Indexed: 06/08/2023]
Abstract
Measurements of the dose equivalent at different distances from the isocenter of the proton therapy center at iThemba LABS were previously performed with a tissue-equivalent proportional counter (TEPC). These measurements showed that the scattered radiation levels were one or two orders of magnitude higher in comparison to other passive scattering delivery systems. In order to reduce these radiation levels, additional shielding was installed shortly after the measurements were done. Therefore, the aim of this work is to quantify and assess the reduction of the secondary doses delivered in the proton therapy room at iThemba LABS after the installation of the additional shielding. This has been performed by measuring microdosimetric spectra with a TEPC at 11 locations around the isocenter when a clinical modulated beam of 200 MeV proton was impinging onto a water phantom placed at the isocenter.
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Affiliation(s)
- S Chiriotti
- Belgian Nuclear Research Centre, SCK•CEN, Boeretang 200, Mol, Belgium
| | - A Parisi
- Belgian Nuclear Research Centre, SCK•CEN, Boeretang 200, Mol, Belgium
| | - F Vanhavere
- Belgian Nuclear Research Centre, SCK•CEN, Boeretang 200, Mol, Belgium
| | - M De Saint-Hubert
- Belgian Nuclear Research Centre, SCK•CEN, Boeretang 200, Mol, Belgium
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Debrot E, Tran L, Chartier L, Bolst D, Guatelli S, Vandevoorde C, de Kock E, Beukes P, Symons J, Nieto-Camero J, Prokopovich DA, Chiriotti S, Parisi A, De Saint-Hubert M, Vanhavere F, Slabbert J, Rosenfeld AB. SOI microdosimetry and modified MKM for evaluation of relative biological effectiveness for a passive proton therapy radiation field. Phys Med Biol 2018; 63:235007. [PMID: 30468682 DOI: 10.1088/1361-6560/aaec2f] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
With more patients receiving external beam radiation therapy with protons, it becomes increasingly important to refine the clinical understanding of the relative biological effectiveness (RBE) for dose delivered during treatment. Treatment planning systems used in clinics typically implement a constant RBE of 1.1 for proton fields irrespective of their highly heterogeneous linear energy transfer (LET). Quality assurance tools that can measure beam characteristics and quantify or be indicative of biological outcomes become necessary in the transition towards more sophisticated RBE weighted treatment planning and for verification of the Monte Carlo and analytical based models they use. In this study the RBE for the CHO-K1 cell line in a passively delivered clinical proton spread out Bragg peak (SOBP) is determined both in vitro and using a silicon-on-insulator (SOI) microdosimetry method paired with the modified microdosimetric kinetic model. The RBE along the central axis of a SOBP with 2 Gy delivered at the middle of the treatment field was found to vary between 1.11-1.98 and the RBE for 10% cell survival between 1.07-1.58 with a 250 kVp x-ray reference radiation and between 1.19-2.34 and 0.95-1.41, respectively, for a Co60 reference. Good agreement was found between RBE values calculated from the SOI-microdosimetry-MKM approach and in vitro. A strong correlation between proton lineal energy and RBE was observed particularly in the distal end and falloff of the SOBP.
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Affiliation(s)
- E Debrot
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, Australia
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Vandevoorde C, Beukes P, Miles X, de Kock E, Symons J, Nieto-Camero J, Tran L, Chartier L, Debrot E, Propokovic D, Chiriotti S, Parisi A, De Saint-Hubert M, Vanhavere F, Rozenfeld A, Slabbert J. Assessment of out-of-field DNA damage and the impact of neutron RBE on secondary cancer risk in paediatric proton therapy. Phys Med 2017. [DOI: 10.1016/s1120-1797(17)30314-9] [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: 10/18/2022] Open
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Beukes P, Mantengu N, Conradie L, Slabbert J. Radiological safety assessment for the commissioning of a 3 MV Tandetron particle accelerator. Phys Med 2017. [DOI: 10.1016/s1120-1797(17)30311-3] [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: 10/18/2022] Open
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Depuydt J, Baeyens A, Barnard S, Beinke C, Benedek A, Beukes P, Buraczewska I, Darroudi F, De Sanctis S, Dominguez I, Monteiro Gil O, Hadjidekova V, Kis E, Kulka U, Lista F, Lumniczky K, M’kacher R, Moquet J, Obreja D, Oestreicher U, Pajic J, Pastor N, Popova L, Regalbuto E, Ricoul M, Sabatier L, Slabbert J, Sommer S, Testa A, Thierens H, Wojcik A, Vral A. O42. Realizing the European Network of Biological Dosimetry ‘RENEB’: Results of 2 intercomparison exercises for the micronucleus assay. Phys Med 2016. [DOI: 10.1016/j.ejmp.2016.07.050] [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: 11/16/2022] Open
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Beukes P, Moller M, Munhenga G, Slabbert J. P11. Dose verification for high-dose bulk industrial 60Co irradiators with chemical dosimeters and gafchromic media. Phys Med 2016. [DOI: 10.1016/j.ejmp.2016.07.078] [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: 11/29/2022] Open
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Beukes P, Depuydt J, Castelein E, Thierens H, Vral A, Slabbert J. O40. The cytogenetic response of human T-lymphocytes to low doses of p(66)/Be neutrons and heterogeneous exposures to 60Co γ-rays. Phys Med 2016. [DOI: 10.1016/j.ejmp.2016.07.048] [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
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Depuydt J, Beukes P, Baert A, Vandersickel V, Thierens H, Slabbert J, Vral A. O44. The differences in induction and repair of DNA DSB induced by 30 kV X-rays, fast neutrons and γ-rays. Phys Med 2016. [DOI: 10.1016/j.ejmp.2016.07.052] [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
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Thema F, Beukes P, Nuru Z, Kotsedi L, Khenfouch M, Dhlamini M, Julies B, Iwuohah E, Maaza M. Physical Properties of Graphene via γ-radiolysis of Exfoliated Graphene Oxide. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.matpr.2015.08.033] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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