Adaptive radiotherapy of lung cancer patients with pleural effusion or atelectasis

Møller, D.S.; Khalil, Azza Ahmed; Knap, M.M.; Hoffmann, Lone

doi:10.1016/j.radonc.2013.10.013

Cited by 83 publications

(95 citation statements)

References 23 publications

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“…Previous studies have documented interfraction motion of the PT and found average PT displacements that range from 5 mm to 9 mm when measured over the course of radiation therapy. 4,5,8,16 AT, which frequently presents in patients with locally advanced lung cancer, [11][12][13] has been shown to increase PT displacements during lung radiation therapy. 4,5 However, unlike these previously mentioned studies, our study used 4-dimensional fan beam CT to quantify AT changes over time and correlate the changes to PT displacement.…”

Section: Discussionmentioning

confidence: 99%

“…[6][7][8][9] Pathoanatomic conditions such as atelectasis (AT) can occur in up to 25% of patients with locally advanced lung cancer and may increase tumor position variability. [10][11][12][13][14] There is a paucity of data that explore interfractional tumor position and shape changes that might be associated with AT. Available data suggest that AT can cause changes in tumor position over the course of radiation therapy that is not normally taken into account with standard setup margins.…”

Section: Introductionmentioning

confidence: 99%

“…5 Therefore, repeated imaging during therapy and adaptive replanning have been suggested to adjust for density changes and tumor displacements that are associated with atelectatic changes. 12 However, the frequency and magnitude of tumor position changes in patients with AT have not been well defined.…”

Section: Introductionmentioning

confidence: 99%

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The Effect of Variations in Atelectasis on Tumor Displacement During Radiation Therapy for Locally Advanced Lung Cancer

Tennyson

Weiss

Sleeman

et al. 2015

International Journal of Radiation Oncology*Biology*Physics

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Purpose: Atelectasis (AT), or collapsed lung, is frequently associated with central lung tumors. We investigated the variation of atelectasis volumes during radiation therapy and analyzed the effect of AT volume changes on the reproducibility of the primary tumor (PT) position. Methods and materials: Twelve patients with lung cancer who had AT and 10 patients without AT underwent repeated 4-dimensional fan beam computed tomography (CT) scans during radiation therapy per protocols that were approved by the institutional review board. Interfraction volume changes of AT and PT were correlated with PT displacements relative to bony anatomy using both a bounding box (BB) method and change in center of mass (COM). Linear regression modeling was used to determine whether PT and AT volume changes were independently associated with PT displacement. PT displacement was compared between patients with and without AT. Results: The mean initial AT volume on the planning CT was 189 cm 3 (37-513 cm 3 ), and the mean PT volume was 93 cm 3 (12-176 cm 3 ). During radiation therapy, AT and PT volumes decreased on average 136.7 cm 3 (20-369 cm 3 ) for AT and 40 cm 3 (À7 to 131 cm 3 ) for PT. Eighty-three percent of patients with AT had at least one unidirectional PT shift that was greater than 0.5 cm outside of the initial BB during treatment. In patients with AT, the maximum PT COM shift was !0.5 cm in all patients and >1 cm in 58% of patients (0.5-2.4 cm). Changes in PT and AT volumes were independently associated with PT displacement (P < .01), and the correlation was smaller with COM (R 2 Z 0.58) compared with the BB method (R 2 Z 0.80). The median root mean squared PT displacement with the BB method was significantly less for patients without AT (0.45 cm) compared with those with AT (0.8cm, P Z .002).

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Effect of Variations in Atelectasis on Tumor Displacement During Radiation Therapy for Locally Advanced Lung Cancer

Tennyson

Weiss

Sleeman

et al. 2015

International Journal of Radiation Oncology*Biology*Physics

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“…[8][9][10] These changes may result in differences between the planned and the actually delivered radiation dose and may require corrective actions. Currently, to detect these dose delivery changes in VMAT, 2-dimensional (2D) integrated or 3-dimensional (3D) integrated EPID dosimetry are used in some centers.…”

Section: Np80mentioning

confidence: 99%

“…Especially in the lung, many geometry changes occur due to pleural effusion, atelectasis, or tumor volume change, influencing the dose delivery and requiring treatment adaptation (patient A). 10 In the bowel area, gas pockets are a frequently occurring source of geometry change. Although this is normally a randomly occurring event and should not influence fractionated treatment drastically, a consistent change in bowel filling can affect the dose to the target volume or OAR (patient B).…”

Section: Site-specific Evaluationmentioning

confidence: 99%

Time-Resolved Versus Integrated Transit Planar Dosimetry for Volumetric Modulated Arc Therapy

Persoon

Podesta

Nijsten

et al. 2016

Technol Cancer Res Treat

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Purpose: It is desirable that dosimetric deviations during radiation treatments are detected. Integrated transit planar dosimetry is commonly used to evaluate external beam treatments such as volumetric-modulated arc therapy. This work focuses on patient geometry changes which result in differences between the planned and the delivered radiation dose. Integrated transit planar dosimetry will average out some deviations. Novel time-resolved transit planar dosimetry compares the delivered dose of volumetric-modulated arc therapy to the planned dose at various time points. Four patient cases are shown where time-resolved transit planar dosimetry detects patient geometry changes during treatment. Methods: A control point to control point comparison between the planned dose and the treatment dose of volumetric-modulated arc therapy beams is calculated using the planning computed tomography and the kV cone-beam computed tomography of the day and evaluated with a time-resolved g function. Results were computed for 4 patients treated with volumetric-modulated arc therapy, each showing an anatomical change: pleural effusion, rectal gas pockets, and tumor regression. Results: In all cases, the geometrical change was detected by time-resolved transit planar dosimetry, whereas integrated transit planar dosimetry showed minor or no indication of the dose discrepancy. Both tumor regression cases were detected earlier in the treatment with time-resolved planar dosimetry in comparison to integrated transit planar dosimetry. The pleural effusion and the gas pocket were detected exclusively with time-resolved transit planar dosimetry. Conclusions: Clinical cases were presented in this proof-of-principle study in which integrated transit planar dosimetry did not detect dosimetrically relevant deviations to the same extent time-resolved transit planar dosimetry was able to. Time-resolved transit planar dosimetry also provides results that can be presented as a function of arc delivery angle allowing easier interpretation compared to integrated transit planar dosimetry.

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Mitigating differential baseline shifts in locally advanced lung cancer patients using an average anatomy model

et al. 2017

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The AAM mitigates systematic errors occurring during treatment due to differential baseline shifts between the primary tumor and involved lymph nodes similar to (or even better than) rCT. The superior performance of the AAM in terms of the systematic error derived from the initial fractions indicates that further analysis of the optimum intervention time is required. This model has the potential to be used as an efficient and accurate alternative for rCT in adaptive radiotherapy of locally advanced lung cancer patients, obviating the need for rescanning and recontouring.

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Adaptive radiotherapy of lung cancer patients with pleural effusion or atelectasis

Cited by 83 publications

References 23 publications

The Effect of Variations in Atelectasis on Tumor Displacement During Radiation Therapy for Locally Advanced Lung Cancer

The Effect of Variations in Atelectasis on Tumor Displacement During Radiation Therapy for Locally Advanced Lung Cancer

Time-Resolved Versus Integrated Transit Planar Dosimetry for Volumetric Modulated Arc Therapy

Mitigating differential baseline shifts in locally advanced lung cancer patients using an average anatomy model

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