Assessment of daily dose accumulation for robustly optimized intensity modulated proton therapy treatment of prostate cancer

Xu, Yihang; Diwanji, Tejan; Brovold, Nellie; Butkus, Michael; Padgett, Kyle R.; Schmidt, Ryder M.; King, Adam; Pra, Alan Dal; Abramowitz, Matthew C.; Pollack, Alan; Dogan, Nesrin

doi:10.1016/j.ejmp.2020.11.035

Cited by 7 publications

(5 citation statements)

References 55 publications

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“…The current usage of internal and setup margins for conventionally fractionated prostate radiation therapy is reported as 6 mm (range, 3-10 mm; except posteriorly 5 mm; range, 0-8 mm), 22 but relatively small margins of 3 to 5 mm are used for IMPT. 23,24 In addition, it is necessary to consider the beam range uncertainty in PBT, and margin recipes of 2.5% to 3.5% of the range plus an additional 1 to 3 mm have been reported. 25 In RGPT, a 3-mm margin was used for internal and setup error because the fiducial markers were within 2 mm of the planned position during treatment.…”

Section: Margins and Dose Optimizationmentioning

confidence: 99%

A Single-Institution Prospective Study to Evaluate the Safety and Efficacy of Real-Time-Image Gated Spot-Scanning Proton Therapy (RGPT) for Prostate Cancer

Nishioka

Hashimoto²,

Mori³

et al. 2022

International Journal of Radiation Oncology*Biology*Physics

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Section: Margins and Dose Optimizationmentioning

confidence: 99%

A Single-Institution Prospective Study to Evaluate the Safety and Efficacy of Real-Time-Image Gated Spot-Scanning Proton Therapy (RGPT) for Prostate Cancer

Nishioka

Hashimoto²,

Mori³

et al. 2022

International Journal of Radiation Oncology*Biology*Physics

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“…However, the patient anatomy including prostate rotation, bladder volume, and rectal shape and other specifics may undergo a variety of changes during the treatment period (about 1–2 months for the prostate cancer treatment) from the time of the planning CT. 5 , 6 , 7 , 8 It has been pointed out that these anatomical changes may cause discrepancies between the dose distribution by the original treatment plan and the actual dose distribution, resulting in insufficient doses to the target or unexpectedly high doses to the OAR. 4 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 In the IMPT treatment technique, the ideal dose distribution can be generated to reduce the rectum dose located dorsal to the prostate and SV without reducing the target coverage in comparison to that with the conventional technique, and thus the non‐uniformed dose distribution of each field tends to have a steep gradient, which makes treatment planning sensitive to any uncertainties such as daily anatomical changes. 20 , 21 , 22 , 23 , 24 Distortion of the actual dose distribution due to the daily anatomical changes may make it difficult to deliver the planned dose accurately and so reduce the essential advantages of IMPT.…”

Section: Introductionmentioning

confidence: 99%

“…In the proton beam community, a 5 mm set-up uncertainty has been widely used in plans of robust optimization for IMPT. On the other hand, Xu et al 16 have recently reported that a 3 mm set-up uncertainty was sufficient in the robust optimization for NART in 10 patients using cone beam CT. However, they have also shown that SV was outside the CTV coverage in some patients.…”

Section: Introductionmentioning

confidence: 99%

Dosimetric advantages of daily adaptive strategy in IMPT for high‐risk prostate cancer

Tamura

Kobashi

Nishioka

et al. 2022

J Applied Clin Med Phys

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Purpose To evaluate the dosimetric advantages of daily adaptive radiotherapy (DART) in intensity‐modulated proton therapy (IMPT) for high‐risk prostate cancer by comparing estimated doses of the conventional non‐adaptive radiotherapy (NART) that irradiates according to an original treatment plan through the entire treatment and the DART that uses an adaptive treatment plan generated by using daily CT images acquired before each treatment. Methods Twenty‐three patients with prostate cancer were included. A treatment plan with 63 Gy (relative biological effectiveness (RBE)) in 21 fractions was generated using treatment planning computed tomography (CT) images assuming that all patients had high‐risk prostate cancer for which the clinical target volume (CTV) needs to include prostate and the seminal vesicle (SV) in our treatment protocol. Twenty‐one adaptive treatment plans for each patient (total 483 data sets) were generated using daily CT images, and dose distributions were calculated. Using a 3 mm set‐up uncertainty in the robust optimization, the doses to the CTV, prostate, SV, rectum, and bladder were compared. Results Estimated accumulated doses of NART and DART in the 23 patients were 60.81 ± 3.47 Gy (RBE) and 63.24 ± 1.04 Gy (RBE) for CTV D99 (p < 0.01), 62.99 ± 1.28 Gy (RBE) and 63.43 ± 1.33 Gy (RBE) for the prostate D99 (p = 0.2529), and 59.07 ± 5.19 Gy (RBE) and 63.17 ± 1.04 Gy (RBE) for SV D99 (p < 0.001). No significant differences were observed between NART and DART in the estimated accumulated dose for the rectum and bladder. Conclusion Compared with the NART, DART was shown to be a useful approach that can maintain the dose coverage to the target without increasing the dose to the organs at risk (OAR) using the 3 mm set‐up uncertainty in the robust optimization in patients with high‐risk prostate cancer.

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“…Many studies have used deep learning based or deformable registration based methods to generate synthetic CT because cone beam CT (CBCT) only or MR images only could not be used directly for dose calculation (Giacometti et al 2020, Chen et al 2021. These methods may introduce additional uncertainty in dosimetry (Thummerer et al 2020, Xu et al 2021. Strict alignment of voxel information between CBCT and planning CT need to be guaranteed but it is difficult to achieve in practice (Sun et al 2021) and inaccurate HUs or image artifacts are still exist in synthetic CT (Dai et al 2021).…”

Section: Introductionmentioning

confidence: 99%

A clinically relevant online patient QA solution with daily CT scans and EPID-based in vivo dosimetry: a feasibility study on rectal cancer

Chen¹,

Zhang²,

Lei³

et al. 2022

Phys. Med. Biol.

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Objective: Adaptive radiation therapy (ART) could protect organs at risk (OARs) while maintain high dose coverage to targets. However, there is still a lack of efficient online patient quality assurance (QA) methods, which is an obstacle to large-scale adoption of ART. We aim to develop a clinically relevant online patient QA solution for ART using daily CT scans and EPID-based in vivo dosimetry. Approach: Ten patients with rectal cancer at our center were included. Patients’ daily CT scans and portal images were collected to generate reconstructed 3D dose distributions. Contours of targets and OARs were recontoured on these daily CT scans by a clinician or an auto-segmentation algorithm, then dose-volume indices were calculated, and the percent deviation of these indices to their original plans were determined. This deviation was regarded as the metric for clinically relevant patient QA. The tolerance level was obtained using a 95% confidence interval of the QA metric distribution. These deviations could be further divided into anatomically relevant or delivery relevant indicators for error source analysis. Finally, our QA solution was validated on an additional six clinical patients. Main results: In rectal cancer, the 95% confidence intervals of the QA metric for PTV ΔD95 (%) were [-3.11%, 2.35%], and for PTV ΔD2 (%) were [-0.78%, 3.23%]. In validation, 68% for PTV ΔD95 (%), and 79% for PTV ΔD2 (%) of the 28 fractions are within tolerances of the QA metrics. one patient’s dosimetric impact of anatomical variations during treatment were observed through the source of error analysis. Significance: The online patient QA solution using daily CT scans and EPID-based in vivo dosimetry is clinically feasible. Source of error analysis has the potential for distinguishing sources of error and guiding ART for future treatments.

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Assessment of daily dose accumulation for robustly optimized intensity modulated proton therapy treatment of prostate cancer

Cited by 7 publications

References 55 publications

A Single-Institution Prospective Study to Evaluate the Safety and Efficacy of Real-Time-Image Gated Spot-Scanning Proton Therapy (RGPT) for Prostate Cancer

A Single-Institution Prospective Study to Evaluate the Safety and Efficacy of Real-Time-Image Gated Spot-Scanning Proton Therapy (RGPT) for Prostate Cancer

Dosimetric advantages of daily adaptive strategy in IMPT for high‐risk prostate cancer

A clinically relevant online patient QA solution with daily CT scans and EPID-based in vivo dosimetry: a feasibility study on rectal cancer

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