Treatment log files as a tool to identify treatment plan sensitivity to inaccuracies in scanned proton beam delivery

Belosi, M.F.; Meer, Robert van der; Laa, P. García de Acilu; Bolsi, Alessandra; Weber, Damien Charles; Lomax, Anthony

doi:10.1016/j.radonc.2017.09.037

Cited by 33 publications

(27 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…FVBOO method would create a challenge in the measurement‐based patient‐specific qualify assurance (PSQA), which needs to be performed for individual fractions instead of the entire plan. However, the hurdle may be overcome by adopting calculation 28–30 and treatment log file analysis 31–33 based PSQA. Measurement‐based QA can be accelerated via scripting and automated delivery.…”

Section: Discussionmentioning

confidence: 99%

Fraction‐variant beam orientation optimization for intensity‐modulated proton therapy

O’Connor

Ruan

et al. 2020

Medical Physics

View full text Add to dashboard Cite

Purpose: To achieve a superior balance between dosimetry and the delivery efficiency of intensitymodulated proton therapy (IMPT) using as few beams as possible in a single fraction, we optimally vary beams in different fractions. Methods: In the optimization, 400~800 feasible noncoplanar beams were included in the candidate pool. For each beam, the doses of all scanning spots covering the target volume and a margin were calculated. The fraction-variant beam orientation optimization (FVBOO) problem was formulated to include three terms: two quadratic dose fidelity terms to penalize the deviation of planning target volume fractional dose and organs at risk (OAR) cumulative doses from prescription, respectively; an L2,1/2-norm group sparsity term to control the number of active beams per fraction to between 1 and 4. The Fast Iterative Shrinkage-Thresholding Algorithm (FISTA) was applied to solve this problem. FVBOO was tested on a patient with base-of-skull (BOS) tumor of 5 fractions (5f) and 30 fractions (30f) with an average number of active beams per fraction varying between 4 and 1. In addition, one bilateral head-and-neck (H&N) patient, and one esophageal cancer (ESG) patient of 30f were tested with about three active beams per fraction. The results were compared with IMPT plans that use fixed beams in each fraction. The fixed beams were selected using the group sparsity term with a fraction-invariant BOO (FIBOO) constraint. Results: Varying beams were chosen in either the 5f or 30f FVBOO plans. While similar number of beams per fraction was selected as the FIBOO plan, the FVBOO plans were able to spare the OARs better, with an average reduction of [Dmean, Dmax] from the FIBOO plans by [0.85, 2.08] Relative Biological Effective Gy (GyRBE) in the 5f plan and [1.87, 4.06] GyRBE in the 30f plans. While reducing the number of beams per fraction in the BOS patient, a three-beam/fraction 5f FVBOO plan performs comparably as the four-beam FIBOO plan and a two-beam/fraction 30f FVBOO plan still provides superior dosimetry. Conclusion: Fraction-variant beam orientation optimization allows the utilization of a larger beam solution space for superior dose distribution in IMPT while maintaining a practical number of beams in each fraction.

show abstract

Section: Discussionmentioning

confidence: 99%

Fraction‐variant beam orientation optimization for intensity‐modulated proton therapy

O’Connor

Ruan

et al. 2020

Medical Physics

View full text Add to dashboard Cite

show abstract

“…Although spot shape, size, and position can be measured using conventional scintillator‐based dosimetry systems, such as the Lynx, these systems are difficult to use during patient treatment due to their bulk. Log file‐based dose reconstruction systems showed, however, that these systems can measure dosimetric information in real time using strip chambers inside the nozzle . Although these systems are good for confirming treatment beams and reconstructing doses in patients, they have several limitations.…”

Section: Discussionmentioning

confidence: 99%

“…Log file-based dose reconstruction systems showed, however, that these systems can measure dosimetric information in real time using strip chambers inside the nozzle. [11][12][13] Although these systems are good for confirming treatment beams and reconstructing doses in patients, they have several limitations. First, their resolution in measuring elaborate scanning proton beams with tightly distributed spots, such as pencil beams of a full width half maximum (FWHM) of a few millimeters, is low (2 mm), whereas the GAPSP provides a resolution comparable to that of an EBT3 film.…”

Section: Discussionmentioning

confidence: 99%

“…The beam shapes and positions recorded in the log files of dose monitoring systems have been used to monitor and reconstruct dose distributions. [11][12][13] However, the 2 mm resolution of the strip chamber arrays was not sufficiently precise to permit analysis of the narrow proton beam spots. Furthermore, these systems were not independent dose monitoring systems.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Feasibility study of a plastic scintillating plate‐based treatment beam fluence monitoring system for use in pencil beam scanning proton therapy

et al. 2019

View full text Add to dashboard Cite

Purpose The purpose of this study was to describe a plastic scintillating plate‐based gantry‐attachable dosimetry system for pencil beam scanning proton therapy to monitor entrance proton beam fluence, and to evaluate the dosimetric characteristics of this system and its feasibility for clinical use. Methods The dosimetry system, consisting of a plastic scintillating plate and a CMOS camera, was attached to a dedicated scanning nozzle and scintillation during proton beam irradiation was recorded. Dose distribution was calculated from the accumulated recorded frames. The dosimetric characteristics (energy dependency, dose linearity, dose rate dependency, and reproducibility) of the gantry‐attachable dosimetry system for use with therapeutic proton beams were measured, and the feasibility of this system during clinical use was evaluated by determining selected quality assurance items at our institution. Results The scintillating plate shortened the range of the proton beam by the water‐equivalent thickness of the plate and broadened the spatial profile of the single proton spot by 11% at 70 MeV. The developed system functioned independently of the beam energy (<1.3%) and showed dose linearity, and also functioned independently of the dose rate. The feasibility of the system for clinical use was evaluated by comparing the measured quality assurance dose distribution to that of the treatment planning system. The gamma passing rate with a criterion of 3%/3 mm was 97.58%. Conclusions This study evaluated the dosimetric characteristics of a plastic scintillating plate‐based dosimetry system for use with scanning proton beams. The ability to account for the interference of the dosimetry system on the therapeutic beam enabled offline monitoring of the entrance beam fluence of the pencil beam scanning proton therapy independent of the treatment system with high resolution and in a cost‐effective manner.

show abstract

“…Several reports have commented on the experiences in other institutions of performing patient-specific quality assurance (PSQA) for spot scanning proton beam therapy, describing the need for multiple measurements per field followed by a γ-index analysis on the 2D dose distributions 1,2 . Various additions to complement PSQA in IMPT have been proposed, such as the use of a second check dose engine 3 , and the use of machine treatment log files 4–6 , or some combination of the two, complemented by measurement 7 . The workflow proposed in this manuscript is a comprehensive approach that incorporates multiple second-check dose engines, a complete log file analysis, as well as dose plane measurements.…”

Section: Introductionmentioning

confidence: 99%

Automation of routine elements for spot‐scanning proton patient‐specific quality assurance

et al. 2018

View full text Add to dashboard Cite

Purpose: At our institution all proton patient plans undergo patient-specific quality assurance (PSQA) prior to treatment delivery. For intensity modulated proton beam therapy, quality assurance is complex and time consuming, and it may involve multiple measurements per field. We reviewed our PSQA workflow and identified the steps that could be automated and developed solutions to improve efficiency. Methods: We used the treatment planning system’s (TPS) capability to support C# scripts to develop an Eclipse scripting application programming interface (ESAPI) script and automate the preparation of the verification phantom plan for measurements. A local area network (LAN) connection between our measurement equipment and shared database was established to facilitate equipment control, measurement data transfer and storage. To improve analysis of the measurement data, a Python script was developed to automatically perform a 2D-3D γ-index analysis comparing measurements in the plane of a 2D detector array with TPS predictions in a water phantom for each acquired measurement. Results: Device connection via LAN granted immediate access to the plan and measurement information for downstream analysis using an online software suite. Automated scripts applied to verification plans reduced time from preparation steps by at least 50%; time reduction from automating γ-index analysis was even more pronounced, dropping by a factor of 10. On average we observed an overall time savings of 55% in completion of the PSQA per patient plan. Conclusions: The automation of the routine tasks in the PSQA workflow significantly reduced the time required per patient, reduced user fatigue and frees up system users from routine and repetitive workflow steps allowing increased focus on evaluating key quality metrics.

show abstract

Treatment log files as a tool to identify treatment plan sensitivity to inaccuracies in scanned proton beam delivery

Cited by 33 publications

References 18 publications

Fraction‐variant beam orientation optimization for intensity‐modulated proton therapy

Fraction‐variant beam orientation optimization for intensity‐modulated proton therapy

Feasibility study of a plastic scintillating plate‐based treatment beam fluence monitoring system for use in pencil beam scanning proton therapy

Automation of routine elements for spot‐scanning proton patient‐specific quality assurance

Contact Info

Product

Resources

About