Determination of the accuracy of implant reconstruction and dose delivery in brachytherapy in The Netherlands and Belgium

Elfrink, R.J.M.; Kolkman-Deurloo, I.K.K.; Kleffens, H.J. van; Rijnders, Alex; Schaeken, B.; Aalbers, Tony H.L; Dries, Wim; Venselaar, J.L.M.

doi:10.1016/s0167-8140(01)00300-0

Cited by 31 publications

(26 citation statements)

References 15 publications

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“…63 A review of dosimetric audit in brachytherapy has also recently been presented by Palmer et al, 64 considering eight international dosimetry audits published over the last two decades in HDR brachytherapy. [65][66][67] The majority of these were concerned with verification of source strength, 65,66,[68][69][70][71][72] although Haworth et al 67 had undertaken a pilot end-to-end audit in Australia, performed in a jig for straight catheters designed to deliver a uniform dose to the measurement point. Within the UK, a recent co-ordinated audit approach has brought together three Meanwhile, there have also been advances in the techniques, which have been identified for audit within the IPEM interdepartmental audit.…”

Section: Recent National Radiotherapy Dosimetry Audits For More Advanmentioning

confidence: 99%

Radiotherapy dosimetry audit: three decades of improving standards and accuracy in UK clinical practice and trials

Clark

Aird

Bolton

et al. 2015

BJR

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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.

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Section: Recent National Radiotherapy Dosimetry Audits For More Advanmentioning

confidence: 99%

Radiotherapy dosimetry audit: three decades of improving standards and accuracy in UK clinical practice and trials

Clark

Aird

Bolton

et al. 2015

BJR

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“…MEDLINE and Embase databases were searched, internet search engines utilized and several brachytherapy experts across the world consulted. Eight peer-reviewed journal publications were obtained that presented results of fully completed audits or pilot audits at several centres, involving dosimetric measurement, 18,[37][38][39][40][41][42][43] and one concerned with a geometric applicator reconstruction audit. 44 Two more journal publications presented methodologies for brachytherapy audit currently in progress, 45,46 and the authors are aware of another two audits currently in progress in the UK that are not yet described in the literature: a well-type chamber intercomparison and an alanine dosimetry phantom measurement of source strength, discussed later.…”

Section: Dosimetric Audits In Brachytherapymentioning

confidence: 99%

“…In 2001, Elfrink et al 39 reported on an audit conducted in the Netherlands and Belgium with the stated aims to determine the accuracy of brachytherapy implant reconstruction and dose delivery for HDR, pulsed dose rate (PDR) or low-dose rate (LDR) remote afterloading treatment equipment, via onsite measurements. At the time, direct three-dimensional (3D) reconstruction of treatment applicators, using CT or MRI, was not widely available, and two-dimensional (2D) planar X-ray image processes were used clinically.…”

Section: Dosimetric Audits In Brachytherapymentioning

confidence: 99%

“…The phantom consists of three PMMA tubes supporting HDR treatment unit catheters at 5 cm radially from, and equally spaced at 120°around, a central TLD holder. The phantom has similar geometry to the equipment used by Elfrink et al 39 ; however, instead of one dwell in each catheter, the EQUAL-ESTRO audit uses two dwells in each to produce a homogeneous dose distribution within the cylindrical TLD detection volume (20 mm height, 3 mm diameter). The audit was performed by irradiating the TLD capsule to a dose of 1 Gy in the dedicated phantom whilst submerged in a water tank, with minimum cube dimensions of 20 cm.…”

Section: Dosimetric Audits In Brachytherapymentioning

confidence: 99%

“…A series of nine dwells in the catheter are used to irradiate the alanine detectors to 10 Gy, a high dose being required for alanine dosimetry. The phantom uses a "three equally spaced radial positions" geometry common with other audit phantoms, 18,39,41,55 but uniquely uses three dosimeters around a central source channel, others having used three source channels around a single central dosimeter. This potentially enables an assessment of radial anisotropy of the source.…”

Section: Dosimetric Audits In Brachytherapymentioning

confidence: 99%

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Dosimetric audit in brachytherapy

Palmer¹,

Bradley²,

Nisbet³

2014

BJR

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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.

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Localization of reference points in electromagnetic tracking data and their application for treatment error detection in interstitial breast brachytherapy

et al. 2023

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BackgroundElectromagnetic tracking (EMT) is a promising technology that holds great potential to advance patient‐specific pre‐treatment verification in interstitial brachytherapy (iBT). It allows easy determination of the implant geometry without line‐of‐sight restrictions and without dose exposure to the patient. What it cannot provide, however, is a link to anatomical landmarks, such as the exit points of catheters or needles on the skin surface. These landmarks are required for the registration of EMT data with other imaging modalities and for the detection of treatment errors such as incorrect indexer lengths, and catheter or needle shifts.PurposeTo develop an easily applicable method to detect reference points in the positional data of the trajectory of an EMT sensor, specifically the exit points of catheters in breast iBT, and to apply the approach to pre‐treatment error detection.MethodsSmall metal objects were attached to catheter fixation buttons that rest against the breast surface to intentionally induce a local, spatially limited perturbation of the magnetic field on which the working principle of EMT relies. This perturbation can be sensed by the EMT sensor as it passes by, allowing it to localize the metal object and thus the catheter exit point. For the proof‐of‐concept, different small metal objects (magnets, washers, and bushes) and EMT sensor drive speeds were used to find the optimal parameters. The approach was then applied to treatment error detection and validated in‐vitro on a phantom. Lastly, the in‐vivo feasibility of the approach was tested on a patient cohort of four patients to assess the impact on the clinical workflow.ResultsAll investigated metal objects were able to measurably perturb the magnetic field, which resulted in missing sensor readings, that is two data gaps, one for the sensor moving towards the tip end and one when retracting from there. The size of the resulting data gaps varied depending on the choice of gap points used for calculation of the gap size; it was found that the start points of the gaps in both directions showed the smallest variability. The median size of data gaps was ⩽8 mm for all tested materials and sensor drive speeds. The variability of the determined object position was ⩽0.5 mm at a speed of 1.0 cm/s and ⩽0.7 mm at 2.5 cm/s, with an increase up to 2.3 mm at 5.0 cm/s. The in‐vitro validation of the error detection yielded a 100% detection rate for catheter shifts of ≥2.2 mm. All simulated wrong indexer lengths were correctly identified. The in‐vivo feasibility assessment showed that the metal objects did not interfere with the routine clinical workflow.ConclusionsThe developed approach was able to successfully detect reference points in EMT data, which can be used for registration to other imaging modalities, but also for treatment error detection. It can thus advance the automation of patient‐specific, pre‐treatment quality assurance in iBT.

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Determination of the accuracy of implant reconstruction and dose delivery in brachytherapy in The Netherlands and Belgium

Cited by 31 publications

References 15 publications

Radiotherapy dosimetry audit: three decades of improving standards and accuracy in UK clinical practice and trials

Radiotherapy dosimetry audit: three decades of improving standards and accuracy in UK clinical practice and trials

Dosimetric audit in brachytherapy

Localization of reference points in electromagnetic tracking data and their application for treatment error detection in interstitial breast brachytherapy

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