1
|
Oliver-Cañamás L, Vijande J, Candela-Juan C, Gimeno-Olmos J, Pujades-Claumarchirant MC, Rovira-Escutia JJ, Ballester F, Perez-Calatayud J. A User-Friendly System for Mailed Dosimetric Audits of 192Ir or 60Co HDR Brachytherapy Sources. Cancers (Basel) 2023; 15:cancers15092484. [PMID: 37173950 PMCID: PMC10177083 DOI: 10.3390/cancers15092484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 04/21/2023] [Accepted: 04/24/2023] [Indexed: 05/15/2023] Open
Abstract
OBJECTIVES The main goal of this work is to design and characterize a user-friendly methodology to perform mailed dosimetric audits in high dose rate (HDR) brachytherapy for systems using either Iridium-192 (192Ir) or Cobalt-60 (60Co) sources. METHODS A solid phantom was designed and manufactured with four catheters and a central slot to place one dosimeter. Irradiations with an Elekta MicroSelectron V2 for 192Ir, and with a BEBIG Multisource for 60Co were performed for its characterization. For the dose measurements, nanoDots, a type of optically stimulated luminescent dosimeters (OSLDs), were characterized. Monte Carlo (MC) simulations were performed to evaluate the scatter conditions of the irradiation set-up and to study differences in the photon spectra of different 192Ir sources (Microselectron V2, Flexisource, BEBIG Ir2.A85-2 and Varisource VS2000) reaching the dosimeter in the irradiation set-up. RESULTS MC simulations indicate that the surface material on which the phantom is supported during the irradiations does not affect the absorbed dose in the nanoDot. Generally, differences below 5% were found in the photon spectra reaching the detector when comparing the Microselectron V2, the Flexisource and the BEBIG models. However, differences up to 20% are observed between the V2 and the Varisource VS2000 models. The calibration coefficients and the uncertainty in the dose measurement were evaluated. CONCLUSIONS The system described here is able to perform dosimetric audits in HDR brachytherapy for systems using either 192Ir or 60Co sources. No significant differences are observed between the photon spectra reaching the detector for the MicroSelectron V2, the Flexisource and the BEBIG 192Ir sources. For the Varisource VS2000, a higher uncertainty is considered in the dose measurement to allow for the nanoDot response.
Collapse
Affiliation(s)
- Laura Oliver-Cañamás
- Servei de Radiofísica i Protecció Radiològica, Consorci Hospitalari Provincial de Castelló (CHPC), 12002 Castelló de la Plana, Spain
| | - Javier Vijande
- Departamento de Física Atómica, Molecular y Nuclear, Universitat de Valencia (UV), 46100 Burjassot, Spain
- Unidad Mixta de Investigación en Radiofísica e Instrumentación Nuclear en Medicina (IRIMED), Instituto de Investigación Sanitaria La Fe (IIS-La Fe), Universitat de Valencia (UV), 46026 València, Spain
- Instituto de Física Corpuscular, Instituto de Física Corpuscular-IFIC (UV-CSIC), 46100 Burjassot, Spain
| | | | - Jose Gimeno-Olmos
- Unitat de Radiofísica, Servei d'Oncologia Radioteràpica, Hospital Universitari i Politècnic La Fe, 46026 València, Spain
| | | | - Juan J Rovira-Escutia
- Servei de Radiofísica i Protecció Radiològica, Consorci Hospital General Universitari de València, 46014 València, Spain
| | - Facundo Ballester
- Departamento de Física Atómica, Molecular y Nuclear, Universitat de Valencia (UV), 46100 Burjassot, Spain
- Unidad Mixta de Investigación en Radiofísica e Instrumentación Nuclear en Medicina (IRIMED), Instituto de Investigación Sanitaria La Fe (IIS-La Fe), Universitat de Valencia (UV), 46026 València, Spain
| | - Jose Perez-Calatayud
- Unidad Mixta de Investigación en Radiofísica e Instrumentación Nuclear en Medicina (IRIMED), Instituto de Investigación Sanitaria La Fe (IIS-La Fe), Universitat de Valencia (UV), 46026 València, Spain
- Unitat de Radiofísica, Servei d'Oncologia Radioteràpica, Hospital Universitari i Politècnic La Fe, 46026 València, Spain
- Hospital Clínica Benidorm, 03501 Benidorm, Spain
| |
Collapse
|
2
|
Miri N, Vial P, Greer PB. Remote dosimetric auditing of clinical trials: The need for vendor specific models to convert images to dose. J Appl Clin Med Phys 2019; 20:175-183. [PMID: 30597730 PMCID: PMC6333142 DOI: 10.1002/acm2.12521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 10/02/2018] [Accepted: 11/04/2018] [Indexed: 11/09/2022] Open
Abstract
INTRODUCTION A previous pilot study has demonstrated the feasibility of a novel image-based approach for remote dosimetric auditing of clinical trials. The approach uses a model to convert in-air acquired intensity modulated radiotherapy (IMRT) images to delivered dose inside a virtual phantom. The model was developed using images from an electronic portal imaging device (EPID) on a Varian linear accelerator. It was tuned using beam profiles and field size factors (FSFs) of a series of square fields measured in water tank. This work investigates the need for vendor specific conversion models for image-based auditing. The EPID measured profile and FSF data for Varian (vendor 1) and Elekta (vendor 2) systems are compared along with the performance of the existing Varian model (VM) and a new Elekta model (EM) for a series of audit IMRT fields measured on vendor 2 systems. MATERIALS AND METHODS The EPID measured beam profile and FSF data were studied for the two vendors to quantify and understand their relevant dosimetric differences. Then, an EM was developed converting EPID to dose in the virtual water phantom using a vendor 2 water tank data and images from corresponding EPID. The VM and EM were compared for predicting vendor 2 measured dose in water tank. Then, the performance of the new EM was compared to the VM for auditing of 54 IMRT fields from four vendor 2 facilities. Statistical significance of using vendor specific models was determined. RESULTS Observed dosimetry differences between the two vendors suggested developing an EM would be beneficial. The EM performed better than VM for vendor 2 square and IMRT fields. The IMRT audit gamma pass rates were (99.8 ± 0.5)%, (98.6 ± 2.3)% and (97.0 ± 3.0)% at respectively 3%/3 mm, 3%/2 mm and 2%/2 mm with improvements at most fields compared with using the VM. For the pilot audit, the difference between gamma results of the two vendors was reduced when using vendor specific models (VM: P < 0.0001, vendor specific models: P = 0.0025). CONCLUSION A new model was derived to convert images from vendor 2 EPIDs to dose for remote auditing vendor 2 deliveries. Using vendor specific models is recommended to remotely audit systems from different vendors, however, the improvements found were not major.
Collapse
Affiliation(s)
- Narges Miri
- School of Mathematical and Physical Sciences, University of Newcastle, Callaghan, NSW, Australia
| | - Philip Vial
- Department of Medical Physics, Liverpool and Macarthur Cancer Therapy Centres, Sydney, Australia.,Ingham Institute of Applied Medical Research, Sydney, Australia.,Institute of Medical Physics, School of Physics, University of Sydney, Sydney, Australia.,South Western Sydney Clinical School, University of New South Wales, Sydney, Australia
| | - Peter B Greer
- School of Mathematical and Physical Sciences, University of Newcastle, Callaghan, NSW, Australia.,Calvary Mater Newcastle Hospital, Newcastle, New South Wales, Australia
| |
Collapse
|
3
|
Lehmann J, Alves A, Dunn L, Shaw M, Kenny J, Keehan S, Supple J, Gibbons F, Manktelow S, Oliver C, Kron T, Williams I, Lye J. Dosimetric end-to-end tests in a national audit of 3D conformal radiotherapy. Phys Imaging Radiat Oncol 2018; 6:5-11. [PMID: 33458381 PMCID: PMC7807562 DOI: 10.1016/j.phro.2018.03.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 03/14/2018] [Accepted: 03/14/2018] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE Independent dosimetry audits improve quality and safety of radiation therapy. This work reports on design and findings of a comprehensive 3D conformal radiotherapy (3D-CRT) Level III audit. MATERIALS AND METHODS The audit was conducted as onsite audit using an anthropomorphic thorax phantom in an end-to-end test by the Australian Clinical Dosimetry Service (ACDS). Absolute dose point measurements were performed with Farmer-type ionization chambers. The audited treatment plans included open and half blocked fields, wedges and lung inhomogeneities. Audit results were determined as Pass Optimal Level (deviations within 3.3%), Pass Action Level (greater than 3.3% but within 5%) and Out of Tolerance (beyond 5%), as well as Reported Not Scored (RNS). The audit has been performed between July 2012 and January 2018 on 94 occasions, covering approximately 90% of all Australian facilities. RESULTS The audit pass rate was 87% (53% optimal). Fifty recommendations were given, mainly related to planning system commissioning. Dose overestimation behind low density inhomogeneities by the analytical anisotropic algorithm (AAA) was identified across facilities and found to extend to beam setups which resemble a typical breast cancer treatment beam placement. RNS measurements inside lung showed a variation in the opposite direction: AAA under-dosed a target beyond lung and over-dosed the lung upstream and downstream of the target. Results also highlighted shortcomings of some superposition and convolution algorithms in modelling large angle wedges. CONCLUSIONS This audit showed that 3D-CRT dosimetry audits remain relevant and can identify fundamental global and local problems that also affect advanced treatments.
Collapse
Affiliation(s)
- Joerg Lehmann
- Australian Clinical Dosimetry Service (ACDS), Australian Radiation Protection and National Safety Agency (ARPANSA), 619 Lower Plenty Road, Yallambie, VIC 3085, Australia
- Institute of Medical Physics, School of Physics A28, University of Sydney NSW 2006, Australia
- School of Mathematical and Physical Sciences, The University of Newcastle, University Drive, Callaghan, NSW 2308, Australia
- School of Science, Royal Melbourne Institute of Technology (RMIT) University, 124 La Trobe Street, Melbourne, VIC 3000, Australia
| | - Andrew Alves
- Australian Clinical Dosimetry Service (ACDS), Australian Radiation Protection and National Safety Agency (ARPANSA), 619 Lower Plenty Road, Yallambie, VIC 3085, Australia
| | - Leon Dunn
- Australian Clinical Dosimetry Service (ACDS), Australian Radiation Protection and National Safety Agency (ARPANSA), 619 Lower Plenty Road, Yallambie, VIC 3085, Australia
| | - Maddison Shaw
- Australian Clinical Dosimetry Service (ACDS), Australian Radiation Protection and National Safety Agency (ARPANSA), 619 Lower Plenty Road, Yallambie, VIC 3085, Australia
- School of Science, Royal Melbourne Institute of Technology (RMIT) University, 124 La Trobe Street, Melbourne, VIC 3000, Australia
| | - John Kenny
- Australian Clinical Dosimetry Service (ACDS), Australian Radiation Protection and National Safety Agency (ARPANSA), 619 Lower Plenty Road, Yallambie, VIC 3085, Australia
| | - Stephanie Keehan
- Australian Clinical Dosimetry Service (ACDS), Australian Radiation Protection and National Safety Agency (ARPANSA), 619 Lower Plenty Road, Yallambie, VIC 3085, Australia
- School of Science, Royal Melbourne Institute of Technology (RMIT) University, 124 La Trobe Street, Melbourne, VIC 3000, Australia
| | - Jeremy Supple
- Australian Clinical Dosimetry Service (ACDS), Australian Radiation Protection and National Safety Agency (ARPANSA), 619 Lower Plenty Road, Yallambie, VIC 3085, Australia
| | - Francis Gibbons
- Australian Clinical Dosimetry Service (ACDS), Australian Radiation Protection and National Safety Agency (ARPANSA), 619 Lower Plenty Road, Yallambie, VIC 3085, Australia
| | - Sophie Manktelow
- Australian Clinical Dosimetry Service (ACDS), Australian Radiation Protection and National Safety Agency (ARPANSA), 619 Lower Plenty Road, Yallambie, VIC 3085, Australia
| | - Chris Oliver
- Australian Clinical Dosimetry Service (ACDS), Australian Radiation Protection and National Safety Agency (ARPANSA), 619 Lower Plenty Road, Yallambie, VIC 3085, Australia
| | - Tomas Kron
- Australian Clinical Dosimetry Service (ACDS), Australian Radiation Protection and National Safety Agency (ARPANSA), 619 Lower Plenty Road, Yallambie, VIC 3085, Australia
- School of Science, Royal Melbourne Institute of Technology (RMIT) University, 124 La Trobe Street, Melbourne, VIC 3000, Australia
- Department of Radiation Oncology, Peter MacCallum Cancer Center, 305 Grattan Street, Melbourne, VIC 3000, Australia
| | - Ivan Williams
- Australian Clinical Dosimetry Service (ACDS), Australian Radiation Protection and National Safety Agency (ARPANSA), 619 Lower Plenty Road, Yallambie, VIC 3085, Australia
| | - Jessica Lye
- Australian Clinical Dosimetry Service (ACDS), Australian Radiation Protection and National Safety Agency (ARPANSA), 619 Lower Plenty Road, Yallambie, VIC 3085, Australia
| |
Collapse
|
4
|
Thomas RA, Bolt MA, Bass G, Nutbrown R, Chen T, Nisbet A, Clark CH. Radiotherapy reference dose audit in the United Kingdom by the National Physical Laboratory: 20 years of consistency and improvements. PHYSICS & IMAGING IN RADIATION ONCOLOGY 2017. [DOI: 10.1016/j.phro.2017.07.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
5
|
Dosimetry intercomparison of four proton therapy institutions in Germany employing spot scanning. Z Med Phys 2017; 27:80-85. [DOI: 10.1016/j.zemedi.2016.06.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Revised: 06/14/2016] [Accepted: 06/29/2016] [Indexed: 11/19/2022]
|
6
|
|
7
|
Abolaban F, Zaman S, Cashmore J, Nisbet A, Clark C. Changes in Patterns of Intensity-modulated Radiotherapy Verification and Quality Assurance in the UK. Clin Oncol (R Coll Radiol) 2016; 28:e28-34. [DOI: 10.1016/j.clon.2016.01.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 12/08/2015] [Accepted: 01/05/2016] [Indexed: 10/22/2022]
|
8
|
Eaton DJ, Bolton S, Thomas RAS, Clark CH. Inter-departmental dosimetry audits - development of methods and lessons learned. J Med Phys 2015; 40:183-9. [PMID: 26865753 PMCID: PMC4728888 DOI: 10.4103/0971-6203.170791] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 08/05/2015] [Accepted: 08/05/2015] [Indexed: 11/10/2022] Open
Abstract
External dosimetry audits give confidence in the safe and accurate delivery of radiotherapy. In the United Kingdom, such audits have been performed for almost 30 years. From the start, they included clinically relevant conditions, as well as reference machine output. Recently, national audits have tested new or complex techniques, but these methods are then used in regional audits by a peer-to-peer approach. This local approach builds up the radiotherapy community, facilitates communication, and brings synergy to medical physics.
Collapse
Affiliation(s)
- David J. Eaton
- Radiotherapy Trials Quality Assurance Group, Mount Vernon Hospital, London, UK
| | - Steve Bolton
- Inter-departmental Audit Group, Institute of Physics and Engineering in Medicine, York, UK
- Department of Medical Physics and Engineering, Christie Hospital, Manchester, UK
| | | | - Catharine H. Clark
- Radiation Dosimetry Group, National Physical Laboratory, London, UK
- Department of Medical Physics, Royal Surrey County Hospital, Guildford, UK
| |
Collapse
|
9
|
Clark CH, Aird EGA, Bolton S, Miles EA, Nisbet A, Snaith JAD, Thomas RAS, Venables K, Thwaites DI. Radiotherapy dosimetry audit: three decades of improving standards and accuracy in UK clinical practice and trials. Br J Radiol 2015; 88:20150251. [PMID: 26329469 DOI: 10.1259/bjr.20150251] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Dosimetry audit plays an important role in the development and safety of radiotherapy. National and large scale audits are able to set, maintain and improve standards, as well as having the potential to identify issues which may cause harm to patients. They can support implementation of complex techniques and can facilitate awareness and understanding of any issues which may exist by benchmarking centres with similar equipment. This review examines the development of dosimetry audit in the UK over the past 30 years, including the involvement of the UK in international audits. A summary of audit results is given, with an overview of methodologies employed and lessons learnt. Recent and forthcoming more complex audits are considered, with a focus on future needs including the arrival of proton therapy in the UK and other advanced techniques such as four-dimensional radiotherapy delivery and verification, stereotactic radiotherapy and MR linear accelerators. The work of the main quality assurance and auditing bodies is discussed, including how they are working together to streamline audit and to ensure that all radiotherapy centres are involved. Undertaking regular external audit motivates centres to modernize and develop techniques and provides assurance, not only that radiotherapy is planned and delivered accurately but also that the patient dose delivered is as prescribed.
Collapse
Affiliation(s)
- Catharine H Clark
- 1 Department of Medical Physics, Royal Surrey County Hospital, Guildford, Surrey, UK.,2 Radiation Dosimetry Group, National Physical Laboratory, Teddington, Middlesex, UK
| | - Edwin G A Aird
- 3 RTTQA Group, Mount Vernon Hospital, Northwood, Middlesex, UK
| | - Steve Bolton
- 4 Medical Physics and Engineering Department, Christie Hospital NHS Foundation Trust, Manchester, UK.,5 Institute of Physics and Engineering in Medicine, York, UK
| | | | - Andrew Nisbet
- 1 Department of Medical Physics, Royal Surrey County Hospital, Guildford, Surrey, UK.,6 Department of Physics, University of Surrey, Guildford, UK
| | - Julia A D Snaith
- 2 Radiation Dosimetry Group, National Physical Laboratory, Teddington, Middlesex, UK
| | - Russell A S Thomas
- 2 Radiation Dosimetry Group, National Physical Laboratory, Teddington, Middlesex, UK
| | - Karen Venables
- 3 RTTQA Group, Mount Vernon Hospital, Northwood, Middlesex, UK
| | - David I Thwaites
- 7 Institute of Medical Physics, School of Physics, University of Sydney, Sydney, NSW, Australia
| |
Collapse
|
10
|
Eaton DJ. Electronic brachytherapy--current status and future directions. Br J Radiol 2015; 88:20150002. [PMID: 25748070 PMCID: PMC4628482 DOI: 10.1259/bjr.20150002] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Revised: 02/28/2015] [Accepted: 03/05/2015] [Indexed: 12/17/2022] Open
Abstract
In the past decade, electronic brachytherapy (EB) has emerged as an attractive modality for the treatment of skin lesions and intraoperative partial breast irradiation, as well as finding wider applications in intracavitary and interstitial sites. These miniature X-ray sources, which operate at low kilovoltage energies (<100 kV), have reduced shielding requirements and inherent portability, therefore can be used outside the traditional realms of the radiotherapy department. However, steep dose gradients and increased sensitivity to inhomogeneities challenge accurate dosimetry. Secondly, ease of use does not mitigate the need for close involvement by medical physics experts and consultant oncologists. Finally, further studies are needed to relate the more heterogeneous dose distributions to clinical outcomes. With these provisos, the practical convenience of EB strongly suggests that it will become an established option for selected patients, not only in radiotherapy departments but also in a range of operating theatres and clinics around the world.
Collapse
Affiliation(s)
- D J Eaton
- NCRI Radiotherapy Trials Quality Assurance Group, Mount Vernon Hospital, London, UK
| |
Collapse
|
11
|
Misson-Yates S, Gonzalez R, McGovern M, Greener A. Comparative dosimetry study of three UK centres implementing total skin electron treatment through external audit. Br J Radiol 2015; 88:20140723. [PMID: 25761213 DOI: 10.1259/bjr.20140723] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE This article describes the external audit measurements conducted in two UK centres implementing total skin electron beam therapy (TSEBT) and the results obtained. METHODS Measurements of output, energy, beam flatness and symmetry at a standard distance (95 or 100 cm SSD) were performed using a parallel plate chamber in solid water. Similarly, output and energy measurements were also performed at the treatment plane for single and dual fields. Clinical simulations were carried out using thermoluminescent dosemeters (TLDs) and Gafchromic® film (International Specialty Products, Wayne, NJ) on an anthropomorphic phantom. RESULTS Extended distance measurements confirmed that local values for the beam dosimetry at Centres A and B were within 2% for outputs and 1-mm agreement of the expected depth at which the dose is 50% of the maximum for the depth-dose curve in water (R50,D) value. Clinical simulation using TLDs) showed an agreement of -1.6% and -6.7% compared with the expected mean trunk dose for each centre, respectively, and a variation within 10% (±1 standard deviation) across the trunk. The film results confirmed that the delivery of the treatment technique at each audited centre complies with the European Organisation for Research and Treatment of Cancer recommendations. CONCLUSION This audit methodology has proven to be a successful way to confirm the agreement of dosimetric parameters for TSEBT treatments at both audited centres and could serve as the basis for an audit template to be used by other audit groups. ADVANCES IN KNOWLEDGE TSEBT audits are not established in the UK owing to a limited number of centres carrying out the treatment technique. This article describes the audits performed at two UK centres prior to their clinical implementation.
Collapse
Affiliation(s)
- S Misson-Yates
- Medical Physics Department, Guy's and St Thomas' NHS Foundation Trust, London, UK
| | | | | | | |
Collapse
|
12
|
A multicentre ‘end to end’ dosimetry audit for cervix HDR brachytherapy treatment. Radiother Oncol 2015; 114:264-71. [DOI: 10.1016/j.radonc.2014.12.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 12/15/2014] [Accepted: 12/17/2014] [Indexed: 11/22/2022]
|
13
|
|
14
|
Abstract
Dosimetric audit is required for the improvement of patient safety in radiotherapy and to aid optimization of treatment. The reassurance that treatment is being delivered in line with accepted standards, that delivered doses are as prescribed and that quality improvement is enabled is as essential for brachytherapy as it is for the more commonly audited external beam radiotherapy. Dose measurement in brachytherapy is challenging owing to steep dose gradients and small scales, especially in the context of an audit. Several different approaches have been taken for audit measurement to date: thimble and well-type ionization chambers, thermoluminescent detectors, optically stimulated luminescence detectors, radiochromic film and alanine. In this work, we review all of the dosimetric brachytherapy audits that have been conducted in recent years, look at current audits in progress and propose required directions for brachytherapy dosimetric audit in the future. The concern over accurate source strength measurement may be essentially resolved with modern equipment and calibration methods, but brachytherapy is a rapidly developing field and dosimetric audit must keep pace.
Collapse
Affiliation(s)
- A L Palmer
- Department of Physics, Faculty of Engineering and Physical Science, University of Surrey, UK
| | | | | |
Collapse
|
15
|
Gershkevitsh E, Pesznyak C, Petrovic B, Grezdo J, Chelminski K, do Carmo Lopes M, Izewska J, Van Dyk J. Dosimetric inter-institutional comparison in European radiotherapy centres: Results of IAEA supported treatment planning system audit. Acta Oncol 2014; 53:628-36. [PMID: 24164104 DOI: 10.3109/0284186x.2013.840742] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND AND PURPOSE One of the newer audit modalities operated by the International Atomic Energy Agency (IAEA) involves audits of treatment planning systems (TPS) in radiotherapy. The main focus of the audit is the dosimetry verification of the delivery of a radiation treatment plan for three-dimensional (3D) conformal radiotherapy using high energy photon beams. The audit has been carried out in eight European countries - Estonia, Hungary, Latvia, Lithuania, Serbia, Slovakia, Poland and Portugal. The corresponding results are presented. MATERIAL AND METHODS The TPS audit reviews the dosimetry, treatment planning and radiotherapy delivery processes using the 'end-to-end' approach, i.e. following the pathway similar to that of the patient, through imaging, treatment planning and dose delivery. The audit is implemented at the national level with IAEA assistance. The national counterparts conduct the TPS audit at local radiotherapy centres through on-site visits. TPS calculated doses are compared with ion chamber measurements performed in an anthropomorphic phantom for eight test cases per algorithm/beam. A set of pre-defined agreement criteria is used to analyse the performance of TPSs. RESULTS TPS audit was carried out in 60 radiotherapy centres. In total, 190 data sets (combination of algorithm and beam quality) have been collected and reviewed. Dosimetry problems requiring interventions were discovered in about 10% of datasets. In addition, suboptimal beam modelling in TPSs was discovered in a number of cases. CONCLUSIONS The TPS audit project using the IAEA methodology has verified the treatment planning system calculations for 3D conformal radiotherapy in a group of radiotherapy centres in Europe. It contributed to achieving better understanding of the performance of TPSs and helped to resolve issues related to imaging, dosimetry and treatment planning.
Collapse
Affiliation(s)
- Eduard Gershkevitsh
- North Estonia Medical Centre, Department of Radiotherapy , Tallinn , Estonia
| | | | | | | | | | | | | | | |
Collapse
|
16
|
Hill R, Healy B, Holloway L, Kuncic Z, Thwaites D, Baldock C. Advances in kilovoltage x-ray beam dosimetry. Phys Med Biol 2014; 59:R183-231. [DOI: 10.1088/0031-9155/59/6/r183] [Citation(s) in RCA: 110] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
|
17
|
CT-based post-implant dosimetry for I-125 prostate brachytherapy: a multi-centre audit in the UK and Ireland. JOURNAL OF RADIOTHERAPY IN PRACTICE 2013. [DOI: 10.1017/s1460396912000489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
AbstractBackground and purposeTo assess the reliability of post-implant CT (PICT) dosimetry for I-125 prostate seed brachytherapy by investigating the variation between centres in performing PICT through a multi-centre audit.Materials and methodsComputerised tomography data sets from four I-125 prostate brachytherapy patients were circulated to nine participating centres. Centres followed local protocol for PICT outlining and seed identification, dosimetry for D90, V100 and V150 for the prostate was reported. Outlines were compared to determine the variation in: quality parameters (D90, V100 and V150), dose-volume histograms and approach to PICT dosimetry between the centres.ResultsThere was significant variation in the prostate outlines drawn by the nine centres; for a prostate with mean volume 43 cm3, the range was 39–57 cm3 which led to variations of D90 of 119–154 Gy (mean 140 Gy) and V100 of 80–93% (mean of 88%). Using automatic seedfinder software reduced discrepancies between centres identifying seeds; overall consistency in seed location was good.ConclusionsThere was a significant uncertainty in the outlining of the prostate volume for PICT dosimetry with an uncertainty value of around ± 20 Gy on D90. PICT is a valuable technique but its accuracy and consistency limitations must be appreciated.
Collapse
|
18
|
Eaton DJ, Earner B, Faulkner P, Dancer N. A national dosimetry audit of intraoperative radiotherapy. Br J Radiol 2013; 86:20130447. [PMID: 24133058 PMCID: PMC3856551 DOI: 10.1259/bjr.20130447] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 09/06/2013] [Accepted: 10/14/2013] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE National dosimetry audits are a fundamental part of quality assurance in radiotherapy, especially for new techniques. Intraoperative radiotherapy with a compact mobile kilovoltage X-ray source is a novel approach for the treatment of breast and other cancers. All seven current clinical sites in the UK were audited by a single visiting group and set of measurement equipment. METHODS Measurements of output, isotropy and depth doses were performed using an ion chamber in solid water, thermoluminescent dosemeters and radiochromic film, respectively. RESULTS The mean difference between measured and planned dose across all centres was -3.2±2.7%. Measured isotropy was within ±3% around the lateral plane of the X-ray source and +11±4% in the forward direction compared with the lateral plane. Measured depth doses were agreed within 5±2% of manufacturer-provided calibration values or a mean gamma index of 97% at a tolerance of 7%/0.5 mm. CONCLUSION Agreement within measurement uncertainties was found for all three parameters except forward anisotropy, which is unlikely to be clinically significant. Steep dose gradients increase the sensitivity to small variations in positioning, but these tests are practical for use in interdepartmental audits and local baseline comparison. ADVANCES IN KNOWLEDGE The first UK interdepartmental audit of intraoperative radiotherapy builds confidence in the delivery of this treatment.
Collapse
Affiliation(s)
- D J Eaton
- Department of Radiotherapy Physics, Royal Free Hospital, London, UK
| | | | | | | |
Collapse
|
19
|
Palmer AL, Lee C, Ratcliffe AJ, Bradley D, Nisbet A. Design and implementation of a film dosimetry audit tool for comparison of planned and delivered dose distributions in high dose rate (HDR) brachytherapy. Phys Med Biol 2013; 58:6623-40. [DOI: 10.1088/0031-9155/58/19/6623] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
20
|
A methodology for dosimetry audit of rotational radiotherapy using a commercial detector array. Radiother Oncol 2013; 108:78-85. [DOI: 10.1016/j.radonc.2013.05.027] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Revised: 04/29/2013] [Accepted: 05/18/2013] [Indexed: 11/17/2022]
|
21
|
Ritter T, Balter JM, Lee C, Roberts D, Roberson PL. Audit tool for external beam radiation therapy departments. Pract Radiat Oncol 2012; 2:e39-e44. [DOI: 10.1016/j.prro.2012.03.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2011] [Revised: 03/26/2012] [Accepted: 03/27/2012] [Indexed: 12/25/2022]
|
22
|
Quality assurance for prospective EORTC radiation oncology trials: The challenges of advanced technology in a multicenter international setting. Radiother Oncol 2011; 100:150-6. [DOI: 10.1016/j.radonc.2011.05.073] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Revised: 05/23/2011] [Accepted: 05/29/2011] [Indexed: 11/20/2022]
|