Impact of interfractional motion on hypofractionated pencil beam scanning proton therapy and <scp>VMAT</scp> delivery for prostate cancer

Moteabbed, M.; Trofimov, Alexei V.; Khan, Fazal Hameed; Wang, Yi; Sharp, G; Zietman, Anthony L.; Efstathiou, Jason A.; Lu, Hsiao‐Ming

doi:10.1002/mp.13091

Cited by 8 publications

(10 citation statements)

References 37 publications

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“…One study evaluated patients receiving adjuvant RT of the prostate bed after prostatectomy 32 . While a 3‐4 mm posterior margin was considered as too small in some studies, 25,32,33,35 it was found adequate in others 26,36–38 . However, the direct quantitative comparison of the studies is hindered by the diverse dosimetric criteria which were used to judge target coverage as adequate and the different navigation techniques applied.…”

Section: Discussionmentioning

confidence: 99%

“…On A number of previous studies analyzed dosimetric consequences of interfractional CTV displacements and deformations by means of dose accumulation to evaluate appropriate PTV margins, based on weekly MV-CBCTs, 32 daily kV-CBCTs, [33][34][35] helical MVCTs 36 or repeat planning CTs. 25,26,37,38 Only in two studies, an endorectal balloon was used. 36,37 The majority of the studies analyzed patients treated with definitive RT.…”

Section: Sfmentioning

confidence: 99%

“…25,26,37,38 Only in two studies, an endorectal balloon was used. 36,37 The majority of the studies analyzed patients treated with definitive RT. One study evaluated patients receiving adjuvant RT of the prostate bed after prostatectomy.…”

Section: Sfmentioning

confidence: 99%

“…32 While a 3-4 mm posterior margin was considered as too small in some studies, 25,32,33,35 it was found adequate in others. 26,[36][37][38] However, the direct quantitative comparison of the studies is hindered by the diverse dosimetric criteria which were used to judge target coverage as adequate and the different navigation techniques applied. Qin et al used gEUD a=−20 as dosimetric criterion, as we did, and found that for 4/22 patients gEUD a=−20 for the accumulated dose was <95% of the planned gEUD a=−20 and fell below 90% for one patient.…”

Section: Sfmentioning

confidence: 99%

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Spatial and dosimetric evaluation of residual distortions of prostate and seminal vesicle bed after image‐guided definitive and postoperative radiotherapy of prostate cancer with endorectal balloon

Levegrün

Pöttgen

Xydis

et al. 2020

J Applied Clin Med Phys

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Purpose: To quantify daily residual deviations from the planned geometry after image-guided prostate radiotherapy with endorectal balloon and to evaluate their effect on the delivered dose distribution.Methods: Daily kV-CBCT imaging was used for online setup-correction in six degrees of freedom (6-dof) for 24 patients receiving definitive (12 RT def patients) or postoperative (12 RT postop patients) radiotherapy with endorectal balloon (overall 739 CBCTs). Residual deviations were evaluated using several spatial and dosimetric variables, including: (a) posterior Hausdorff distance HD post (=maximum distance between planned and daily CTV contour), (b) point P worst with largest HD post over all fractions, (c) equivalent uniform dose using a cell survival model (EUD SF ) and the generalized EUD concept (gEUD a with parameter a = −7 and a = −20). EUD values were determined for planned (EUD plan SF ), daily (EUD ind SF ), and delivered dose distributions (EUD accum SF ) for plans with 6 mm (=clinical plans) and 2 mm CTV-to-PTV margin. Time series analyses of interfractional spatial and dosimetric deviations were conducted.Results: Large HD post values ≥ 12.5 mm (≥15 mm) were observed in 20/739 (5/739) fractions distributed across 7 (3) patients. Points P worst were predominantly located at the posterior CTV boundary in the seminal vesicle region (16/24 patients, 6/7 patients with HD post ≥ 12.5 mm). Time series analyses revealed a stationary white noise characteristic of HD post and relative dose at P worst . The EUD SF difference between planned and accumulated dose distributions was < 5.4% for all 6-mm plans. Evaluating 2-mm plans, EUD SF deteriorated by < 10% (<5%) in 75% (58.5%) of the patients. EUD accum SF was well described by the median value of the EUD ind SF distribution. PTV margin calculation at P worst yielded 8.8 mm.Conclusions: Accumulated dose distributions in prostate radiotherapy with endorectal balloon are forgiving of considerable residual distortions after 6-dof patient setup if they are observed in a minority of fractions and the median value of EUD ind SF

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Section: Discussionmentioning

confidence: 99%

Section: Sfmentioning

confidence: 99%

Section: Sfmentioning

confidence: 99%

Section: Sfmentioning

confidence: 99%

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Spatial and dosimetric evaluation of residual distortions of prostate and seminal vesicle bed after image‐guided definitive and postoperative radiotherapy of prostate cancer with endorectal balloon

Levegrün

Pöttgen

Xydis

et al. 2020

J Applied Clin Med Phys

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“…Several studies have investigated inter-fractional prostate variability by means of repeated CT, kV or online CBCT (for a review on this topic, see [8] ). Mean prostate displacements of up to 9 mm between fractions have been reported, with the largest deviation found in the anterior-posterior (AP) direction [8] , [9] . Seminal vesicles, which are included in the target volume for intermediate and high risk disease patients, are subjected to even larger inter-fractional shifts than the prostate [10] .…”

Section: Introductionmentioning

confidence: 99%

Clinical implementation of magnetic resonance imaging guided adaptive radiotherapy for localized prostate cancer

Tetar

Bruynzeel

Lagerwaard

et al. 2019

Physics and Imaging in Radiation Oncology

138

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A B S T R A C TBackground and purpose: Magnetic resonance-guided radiation therapy (MRgRT) has recently become available in clinical practice and is expected to expand significantly in coming years. MRgRT offers marker-less continuous imaging during treatment delivery, use of small clinical target volume (CTV) to planning target volume (PTV) margins, and finally the option to perform daily plan re-optimization. Materials and methods: A total of 140 patients (700 fractions) have been treated with MRgRT and online plan adaptation for localized prostate cancer since early 2016. Clinical workflow for MRgRT of prostate cancer consisted of patient selection, simulation on both MR-and computed tomography (CT) scan, inverse intensitymodulated radiotherapy (IMRT) treatment planning and daily plan re-optimization prior to treatment delivery with partial organs at risk (OAR) recontouring within the first 2 cm outside the PTV. For each adapted plan online patient-specific quality assurance (QA) was performed by means of a secondary Monte Carlo 3D dose calculation and gamma analysis comparison. Patient experiences with MRgRT were assessed using a patientreported outcome questionnaire (PRO-Q) after the last fraction. Results: In 97% of fractions, MRgRT was delivered using the online adapted plan. Intrafractional prostate drifts necessitated 2D-corrections during treatment in approximately 20% of fractions. The average duration of an uneventful fraction of MRgRT was 45 min. showed that MRgRT was generally well tolerated, with disturbing noise sensations being most commonly reported. Conclusions: MRgRT with daily online plan adaptation constitutes an innovative approach for delivering SBRT for prostate cancer and appears to be feasible, although necessitating extended timeslots and logistical challenges.

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Interfractional robustness of scanning carbon ion radiotherapy for prostate cancer: An analysis based on dose distribution from daily in‐room CT images

Tsuchida

Minohara

Kusano

et al. 2021

J Applied Clin Med Phys

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Purpose: We analyzed interfractional robustness of scanning carbon ion radiotherapy (CIRT) for prostate cancer based on the dose distribution using daily in-room computed tomography (CT) images. Materials and Methods:We analyzed 11 consecutive patients treated with scanning CIRT for localized prostate cancer in our hospital between December 2015 and January 2016. In-room CT images were taken under treatment conditions in every treatment session. The dose distribution on each in-room CT image was recalculated, while retaining the pencil beam arrangement of the initial treatment plan.Then, the dose-volume histogram (DVH) parameters including the percentage of the clinical target volume (CTV) with 95% and 90% of the prescribed dose area (V95% of CTV, V90% of CTV) and V80% of rectum were calculated. The acceptance criteria for the CTV and rectum were set at V95% of CTV ≥95%, V90% of CTV ≥98%, and V80% of rectum < 10 ml.Results: V95% of CTV, V90% of CTV, and V80% of rectum for the reproduced plans were 98.8 ± 3.49%, 99.5 ± 2.15%, and 4.39 ± 3.96 ml, respectively. Acceptance of V95% of CTV, V90% of CTV, and V80% of rectum was obtained in 123 (94%), 125 (95%) and 117 sessions (89%), respectively. Acceptance of the mean dose of V95% of CTV, V90% of CTV, and V80% of rectum for each patient was obtained in 10 (91%), 10 (91%), and 11 patients (100%), respectively. Conclusions:We demonstrated acceptable interfractional robustness based on the dose distribution in scanning CIRT for prostate cancer.

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Impact of interfractional motion on hypofractionated pencil beam scanning proton therapy and VMAT delivery for prostate cancer

Cited by 8 publications

References 37 publications

Spatial and dosimetric evaluation of residual distortions of prostate and seminal vesicle bed after image‐guided definitive and postoperative radiotherapy of prostate cancer with endorectal balloon

Spatial and dosimetric evaluation of residual distortions of prostate and seminal vesicle bed after image‐guided definitive and postoperative radiotherapy of prostate cancer with endorectal balloon

Clinical implementation of magnetic resonance imaging guided adaptive radiotherapy for localized prostate cancer

Interfractional robustness of scanning carbon ion radiotherapy for prostate cancer: An analysis based on dose distribution from daily in‐room CT images

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