Analysis of uncertainties in the IAEA/WHO TLD postal dose audit system

Iżewska, J.; Hultqvist, Martha; Bera, P.

doi:10.1016/j.radmeas.2008.01.011

Cited by 28 publications

(16 citation statements)

References 5 publications

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“…Reference dosimetry -The framework used for the dissemination of standards in radiation metrology is described and the uncertainties applicable to the current reference standards used in radiotherapy are given for brachytherapy and EBRT with low, medium and high energy x-ray beams. In the clinical environment, reference beam calibration can be confirmed using dosimetry audits and an overview of the uncertainties obtained in beam calibration of high energy photon beams from the IAEA/WHO TLD postal dose audit system is given [15]. Also, ensuring a small uncertainty in the dosimetry of small and non-standard beams is of importance, in particular for stereotactic and IMRT treatments, including VMAT.…”

Section: Levels Of Accuracy Practically Achievable (Dosimetric Geomementioning

confidence: 99%

Accuracy requirements and uncertainties in radiotherapy: a report of the International Atomic Energy Agency

et al. 2016

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The report concludes with nine general recommendations: (1) Radiotherapy should be applied as accurately as reasonably achievable, technical and biological factors being taken into account. (2) For consistency in prescribing, reporting and recording, recommendations of the International Commission on Radiation Units and Measurements should be implemented. (3) Each institution should determine uncertainties for their treatment procedures. Sample data are tabulated for typical clinical scenarios with estimates of the levels of accuracy that are practically achievable and suggested action levels. (4) Independent dosimetry audits should be performed regularly. (5) Comprehensive quality assurance programs should be in place. (6) Professional staff should be appropriately educated and adequate staffing levels should be maintained. (7) For reporting purposes, uncertainties should be presented. (8) Manufacturers should provide training on all equipment. (9) Research should aid in improving the accuracy of radiotherapy. Some example research projects are suggested.

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Section: Levels Of Accuracy Practically Achievable (Dosimetric Geomementioning

confidence: 99%

Accuracy requirements and uncertainties in radiotherapy: a report of the International Atomic Energy Agency

et al. 2016

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“…For TLD, approximately 165 mg of LiF powder was encapsulated in plastic capsules (2.8 cm length, 0.5 cm diameter). TLD powder from the capsules was read/analyzed with a PCL3 TLD reader (Fimel, France) following the established IAEA protocol [28]. The uncertainty in the TLD measurements was 1.6% (1 standard deviation (SD)).…”

Section: Dosimetric Evaluationmentioning

confidence: 99%

Testing the methodology for a dosimetric end-to-end audit of IMRT/VMAT: results of IAEA multicentre and national studies

et al. 2019

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Introduction: Within an International Atomic Energy Agency (IAEA) coordinated research project (CRP), a remote end-to-end dosimetric quality audit for intensity modulated radiation therapy (IMRT)/ volumetric arc therapy (VMAT) was developed to verify the radiotherapy chain including imaging, treatment planning and dose delivery. The methodology as well as the results obtained in a multicentre pilot study and national trial runs conducted in close cooperation with dosimetry audit networks (DANs) of IAEA Member States are presented. Material and methods: A solid polystyrene phantom containing a dosimetry insert with an irregular solid water planning target volume (PTV) and organ at risk (OAR) was designed for this audit. The insert can be preloaded with radiochromic film and four thermoluminescent dosimeters (TLDs). For the audit, radiotherapy centres were asked to scan the phantom, contour the structures, create an IMRT/VMAT treatment plan and irradiate the phantom. The dose prescription was to deliver 4 Gy to the PTV in two fractions and to limit the OAR dose to a maximum of 2.8 Gy. The TLD measured doses and film measured dose distributions were compared with the TPS calculations. Results: Sixteen hospitals from 13 countries and 64 hospitals from 6 countries participated in the multicenter pilot study and in the national runs, respectively. The TLD results for the PTV were all within ±5% acceptance limit for the multicentre pilot study, whereas for national runs, 17 participants failed to meet this criterion. All measured doses in the OAR were below the treatment planning constraint. The film analysis identified seven plans in national runs below the 90% passing rate gamma criteria. Conclusion: The results proved that the methodology of the IMRT/VMAT dosimetric end-to-end audit was feasible for its intended purpose, i.e., the phantom design and materials were suitable; the phantom was easy to use and it was robust enough for shipment. Most importantly the audit methodology was capable of identifying suboptimal IMRT/VMAT delivery.

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“…The use of TLDs is a well-established technique, used for several decades in radiotherapy for instance for postal dose audit services. [50][51][52] TLDs have also been used for many types of in vivo dosimetry of EBRT such as during total body irradiation and in organs at risk, and for in vivo dose verification in brachytherapy. 21,22,53 TLD materials, upon absorption of radiation, retain part of the absorbed energy in metastable states.…”

Section: Iib Detectors For Passive In Vivo Dosimetrymentioning

confidence: 99%

“…Such an activity might be similar to a dosimetric audit, as performed for instance by the IAEA (Ref. 52) or RPC, 101 and will require phantoms that can accommodate various IVD systems. For example, one could envision a simple phantom to be sent to centers that are often asked to measure skin or surface doses on patients as well as out-of-field doses.…”

Section: Future Needs and Evolving Technology For Ivdmentioning

confidence: 99%

In vivo dosimetry in external beam radiotherapy

et al. 2013

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In vivo dosimetry (IVD) is in use in external beam radiotherapy (EBRT) to detect major errors, to assess clinically relevant differences between planned and delivered dose, to record dose received by individual patients, and to fulfill legal requirements. After discussing briefly the main characteristics of the most commonly applied IVD systems, the clinical experience of IVD during EBRT will be summarized. Advancement of the traditional aspects of in vivo dosimetry as well as the development of currently available and newly emerging noninterventional technologies are required for large-scale implementation of IVD in EBRT. These new technologies include the development of electronic portal imaging devices for 2D and 3D patient dosimetry during advanced treatment techniques, such as IMRT and VMAT, and the use of IVD in proton and ion radiotherapy by measuring the decay of radiation-induced radionuclides. In the final analysis, we will show in this Vision 20∕20 paper that in addition to regulatory compliance and reimbursement issues, the rationale for in vivo measurements is to provide an accurate and independent verification of the overall treatment procedure. It will enable the identification of potential errors in dose calculation, data transfer, dose delivery, patient setup, and changes in patient anatomy. It is the authors' opinion that all treatments with curative intent should be verified through in vivo dose measurements in combination with pretreatment checks.

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Analysis of uncertainties in the IAEA/WHO TLD postal dose audit system

Cited by 28 publications

References 5 publications

Accuracy requirements and uncertainties in radiotherapy: a report of the International Atomic Energy Agency

Accuracy requirements and uncertainties in radiotherapy: a report of the International Atomic Energy Agency

Testing the methodology for a dosimetric end-to-end audit of IMRT/VMAT: results of IAEA multicentre and national studies

In vivo dosimetry in external beam radiotherapy

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