In vivo dosimetry with optically stimulated luminescent dosimeters for conformal and intensity-modulated radiation therapy: A 2-year multicenter cohort study

Riegel, Adam C.; Chen, Yu; Kapur, Ajay; Apicello, Laura; Kuruvilla, Anju; Rea, Anthony; Jamshidi, A; Potters, Louis

doi:10.1016/j.prro.2016.09.001

Cited by 12 publications

(15 citation statements)

References 27 publications

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“…This report introduces the concept of an "uncertainty budget" for OSLD-based IVD, which includes various well-studied physical dependencies added in quadrature but few clinical ones. In a previous study, we investigated over 10,000 clinical OSLD measurements and found that the variability was ± 10.3%, nearly twice the uncertainty budget that TG-191 proposes (5.2%) [9,10]. We hypothesized that placement error could explain the disagreement between the TG 191 uncertainty budget and our clinical findings [10].…”

Section: Discussionmentioning

confidence: 76%

“…The analysis included a variety of treatment techniques (including intensity-modulated delivery), modalities, anatomical sites and placement locations. We found the accuracy of OSLDs to be within 0.3% of planned doses but observed one-sigma precision over 10%, approximately twice the proposed uncertainty budget in TG-191 [10]. Given the high-dose gradients in IMRT and VMAT, placement error may have a considerable role in variability of measured-to-planned dose agreement.…”

Section: The Forthcoming American Association Of Physicists In Medicimentioning

confidence: 69%

“…In previous work, we investigated the accuracy and precision of OSLDs in a clinical setting with over 10,000 OSLD measurements [10]. The analysis included a variety of treatment techniques (including intensity-modulated delivery), modalities, anatomical sites and placement locations.…”

Section: The Forthcoming American Association Of Physicists In Medicimentioning

confidence: 99%

“…At the physician's request, OSLDs were placed weekly throughout a patient's radiotherapy treatment with locations determined by a physicist. The location of the dosimeters was treatment site specific and based on two factors: dosimetric homogeneity (avoiding field edges and sharp dose gradients) [12,13] and reproducibility (specifying a practical, accessible location on the patient) [10]. Placement locations were recorded as gantry angle and a two-dimensional offset from the central axis of a specific isocenter to facilitate placement using the linear accelerator field light.…”

Section: In Vivo Dosimetry Proceduresmentioning

confidence: 99%

“…The patient was treated, the OSLD was removed and read at least one hour after irradiation, and the resulting measured dose was expressed as a percent difference from the planned dose. A detailed description of measured dose calculation and reader calibration is beyond the scope of the current work but can be found in prior work [10].…”

Section: In Vivo Dosimetry Proceduresmentioning

confidence: 99%

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Dosimetric impact of placement errors in optically stimulated luminescent in vivo dosimetry in radiotherapy

Tariq

Gomez

Riegel

2019

Physics and Imaging in Radiation Oncology

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Introduction: Studies have suggested that optically stimulated luminescent dosimeters (OSLDs) can be used for in vivo dosimetry of intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT). Clinical uncertainties such as placement error have not been thoroughly investigated. The purpose of this work was to measure OSLD placement error in a clinical sample and analyze its dosimetric impact. Methods and materials: The analysis consisted of three parts: first, quantification of placement error in a clinical sample of 128 patients yielding 293 cone-beam CT (CBCT) with visible OSLDs registered to the treatment plan; Second, correlation of placement error and clinical OSLD measurements; third, simulation of dosimeter placement in the treatment plan and correlation of recalculated dose with placement error. Results: In the first analysis, average placement error was 9.7 ± 9.5 mm. In the second analysis, placement error and measured-to-planned dose agreement yielded no correlation (R 2 = 0.02) for a subsample of 77 CBCTs of 55 head-and-neck patients. Average placement error was 7.0 ± 6.0 mm. Several factors, including image-guided shifts, introduced uncharacterized uncertainty to the measured-to-planned dose agreement. The third analysis isolated placement error from these other effects. Average dosimetric error was −2.4 ± 19.3%. Simulated dosimetric impact was weakly correlated with placement error (R 2 = 0.39). Removing outliers reduced the average dosimetric error to −2.1 ± 10.9%, marginally improving the correlation (R 2 = 0.44). Conclusion: Placement error can substantially impact measured-to-planned dose agreement of OSLDs in high gradient regions, demonstrating the criticality of accurate dosimeter placement for IMRT and VMAT treatments.

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Section: Discussionmentioning

confidence: 76%

Section: The Forthcoming American Association Of Physicists In Medicimentioning

confidence: 69%

Section: The Forthcoming American Association Of Physicists In Medicimentioning

confidence: 99%

Section: In Vivo Dosimetry Proceduresmentioning

confidence: 99%

Section: In Vivo Dosimetry Proceduresmentioning

confidence: 99%

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Dosimetric impact of placement errors in optically stimulated luminescent in vivo dosimetry in radiotherapy

Tariq

Gomez

Riegel

2019

Physics and Imaging in Radiation Oncology

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Dosimetric impact of hollow intraoral stents for head and neck cancer radiotherapy: A phantom study

Song

et al. 2023

J Applied Clin Med Phys

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PurposeTo investigate the dosimetric impact of the calculation boundaries and dose calculation algorithms of radiotherapy in head and neck cancer patients with an opened oral cavity connected to the exterior by a hollow intraoral positioning stent.Methods and MaterialsA homemade silicone phantom with an opened oral cavity was placed in a CIRS head phantom to model head and neck cancer patients with a hollow intraoral positioning stent. 3D‐CRT plans were designed on CT images of the phantom in Monaco and Pinnacle3 treatment planning systems (TPSs) with the same beam parameters. The default boundary and manually extrapolated boundary were both adopted in these two TPSs to explore the dosimetric impact on treatment plans. The nanoDot™ optically stimulated luminescence dosimeters (OSLDs) were chosen to measure the planned dose surrounding the oral cavity of the head phantom after calibration.ResultThe doses in the air cavity and two measuring points at the joint area were dramatically changed from 0.0, 92.4 and 148.8 cGy to 177.8, 244.2 and 244.1 cGy in Monaco after adopting the extrapolated boundary. While the calculated doses at the same place were changed from 61.2, 143.7 and 198.3 cGy to 175.4, 234.7 and 233.2 cGy in Pinnacle3 with a similar calculation boundary. For the Monaco TPS, the relative errors compared to the OSLD measured doses were 2.94 ± 1.93%, 0.53 ± 8.64%, 2.65 ± 1.87% and 3.93 ± 1.69% at 4 measuring positions. In contrast, the relative errors 4.03 ± 1.93%, 4.85 ± 8.64%, 7.61 ± 1.87% and 5.61 ± 1.69% were observed in Pinnacle3.ConclusionThe boundary setting of an opened oral cavity in TPSs has a significant dosimetric impact on head and neck cancer radiotherapy. An extrapolated boundary should be manually set up to include the whole oral cavity in the dose calculation domain to avoid major dose deviations.

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AAPM TG 191: Clinical use of luminescent dosimeters: TLDs and OSLDs

Kry

Alvarez

Cygler³

et al. 2019

Medical Physics

128

142

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Thermoluminescent dosimeters (TLD) and optically stimulated luminescent dosimeters (OSLD) are practical, accurate, and precise tools for point dosimetry in medical physics applications. The charges of Task Group 191 were to detail the methodologies for practical and optimal luminescence dosimetry in a clinical setting. This includes: (a) to review the variety of TLD/OSLD materials available, including features and limitations of each; (b) to outline the optimal steps to achieve accurate and precise dosimetry with luminescent detectors and to evaluate the uncertainty induced when less rigorous procedures are used; (c) to develop consensus guidelines on the optimal use of luminescent dosimeters for clinical practice; and (d) to develop guidelines for special medically relevant uses of TLDs/OSLDs such as mixed photon/neutron field dosimetry, particle beam dosimetry, and skin dosimetry. While this report provides general guidelines for TLD and OSLD processes, the report provides specific details for TLD‐100 and nanoDotTM dosimeters because of their prevalence in clinical practice.

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In vivo dosimetry with optically stimulated luminescent dosimeters for conformal and intensity-modulated radiation therapy: A 2-year multicenter cohort study

Cited by 12 publications

References 27 publications

Dosimetric impact of placement errors in optically stimulated luminescent in vivo dosimetry in radiotherapy

Dosimetric impact of placement errors in optically stimulated luminescent in vivo dosimetry in radiotherapy

Dosimetric impact of hollow intraoral stents for head and neck cancer radiotherapy: A phantom study

AAPM TG 191: Clinical use of luminescent dosimeters: TLDs and OSLDs

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