3D reconstruction of scintillation light emission from proton pencil beams using limited viewing angles—a simulation study

Hui, Cheukkai; Robertson, Daniel; Beddar, Sam

doi:10.1088/0031-9155/59/16/4477

Cited by 15 publications

(10 citation statements)

References 26 publications

(42 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Indeed, the depth-by-depth 2D interpolation of the 3D calculated dose along the proton beam direction, and the subsequent 2D comparison to the measured dose when applied to proton field's distal penumbra, is analogous to the point-by-point comparison for the photon beam's lateral penumbra. Similar error in dose comparison is expected as predicted previously (25)(26)(27)(28)(29) and, indeed, demonstrated in Fig. 3.…”

Section: Discussionsupporting

confidence: 91%

Three‐dimensional gamma criterion for patient‐specific quality assurance of spot scanning proton beams

Chang

Poole

Teran

et al. 2015

J Applied Clin Med Phys

View full text Add to dashboard Cite

The purpose of this study was to evaluate the effectiveness of full three‐dimensional (3D) gamma algorithm for spot scanning proton fields, also referred to as pencil beam scanning (PBS) fields. The difference between the full 3D gamma algorithm and a simplified two‐dimensional (2D) version was presented. Both 3D and 2D gamma algorithms are used for dose evaluations of clinical proton PBS fields. The 3D gamma algorithm was implemented in an in‐house software program without resorting to 2D interpolations perpendicular to the proton beams at the depths of measurement. Comparison between calculated and measured dose points was carried out directly using Euclidian distance in 3D space and the dose difference as a fourth dimension. Note that this 3D algorithm faithfully implemented the original concept proposed by Low et al. (1998) who described gamma criterion using 3D Euclidian distance and dose difference. Patient‐specific proton PBS plans are separated into two categories, depending on their optimization method: single‐field optimization (SFO) or multifield optimized (MFO). A total of 195 measurements were performed for 58 SFO proton fields. A MFO proton plan with four fields was also calculated and measured, although not used for treatment. Typically three different depths were selected from each field for measurements. Each measurement was analyzed by both 3D and 2D gamma algorithms. The resultant 3D and 2D gamma passing rates are then compared and analyzed. Comparison between 3D and 2D gamma passing rates of SFO fields showed that 3D algorithm does show higher passing rates than its 2D counterpart toward the distal end, while little difference is observed at depths away from the distal end. Similar phenomenon in the lateral penumbra was well documented in photon radiation therapy, and in fact brought about the concept of gamma criterion. Although 2D gamma algorithm has been shown to suffice in addressing dose comparisons in lateral penumbra for photon intensity‐modulation radiation therapy (IMRT) plans, results here showed that a full 3D algorithm is required for proton dose comparisons due to the existence of Bragg peaks and distal penumbra. A MFO proton plan with four fields was also measured and analyzed. Sharp dose gradients exist in MFO proton fields, both in the middle of the modulation and toward the most distal layers. Decreased 2D gamma passing rates at locations of high dose gradient are again observed as in the SFO fields. Results confirmed that a full 3D algorithm for gamma criterion is needed for proton PBS plan's dose comparisons. The 3D gamma algorithm is implemented by an in‐house software program. Patient‐specific proton PBS plans are measured and analyzed using both 3D and 2D gamma algorithms. For measurements performed at depths with large dose gradients along the beam direction, gamma comparison passing rates using 2D algorithm is lower than those obtained with the full 3D algorithm.PACS number: 87.53.Bn, 87.53.Jw, 87.55.de, 87.55.kd, 87.55.ne, 87.55.Qr

show abstract

Section: Discussionsupporting

confidence: 91%

Three‐dimensional gamma criterion for patient‐specific quality assurance of spot scanning proton beams

Chang

Poole

Teran

et al. 2015

J Applied Clin Med Phys

View full text Add to dashboard Cite

show abstract

“…A simulation study with this detector configuration performed by our group demonstrated the feasibility of this setup for 3D reconstruction (Hui et al 2014). In addition, ionization quenching correction models that will be required for gathering correct dose information from the scintillation light map are currently being investigated.…”

Section: Discussionmentioning

confidence: 96%

Performance characterization of a 3D liquid scintillation detector for discrete spot scanning proton beam systems

Darne¹,

Alsanea²,

Robertson³

et al. 2017

Phys. Med. Biol.

Self Cite

View full text Add to dashboard Cite

Existing systems for proton beam dosimetry are limited in their ability to provide a complete, accurate, and detailed account of volumetric dose distribution. In this work, we describe the design and development of a portable, fast, and reusable liquid scintillator-based three-dimensional (3D) optical detection system for use in proton therapy. Our long-term goal is to use this system clinically for beam characterization, dosimetry, and quality assurance studies of discrete spot scanning proton beam systems. The system used a 20 × 20 × 20-cm3 liquid scintillator volume. Three mutually orthogonal cameras surrounding this volume captured scintillation photons emitted in response to the proton beams. The cameras exhibited a mean spatial resolution of 0.21 mm over the complete detection volume and a temporal resolution of 11 msec. The system is shown to be capable of capturing all 94 beam energies delivered by a synchrotron and performing rapid beam range measurements with a mean accuracy of 0.073 ±0.030 mm over all energies. The range measurement uncertainty for doses less than 1 cGy was found to be ±0.355 mm, indicating high precision for low dose detection. Finally, we demonstrated that using multiple cameras allowed for the precise locations of the delivered beams to be tracked in 3D. We conclude that this detector is capable of real-time and accurate tracking of dynamic spot beam deliveries in 3D. The high-resolution light profiles it generates will be useful for future 3D construction of dose maps.

show abstract

“…The two proton beams were shifted laterally to five different tank locations such that the maximum dose was located at −84 mm, −42 mm, 0 mm, +42 mm, or +84 mm relative to the scintillator tank center. The dose grids were then numerically projected to the CCD camera (Hui et al , 2014) and proton beam ranges were calculated and compared.…”

Section: Methodsmentioning

confidence: 99%

Fast range measurement of spot scanning proton beams using a volumetric liquid scintillator detector

Hui

Robertson

Alsanea

et al. 2015

Biomed. Phys. Eng. Express

Self Cite

View full text Add to dashboard Cite

Accurate confirmation and verification of the range of spot scanning proton beams is crucial for correct dose delivery. Current methods to measure proton beam range using ionization chambers are either time-consuming or result in measurements with poor spatial resolution. The large-volume liquid scintillator detector allows real-time measurements of the entire dose profile of a spot scanning proton beam. Thus, liquid scintillator detectors are an ideal tool for measuring the proton beam range for commissioning and quality assurance. However, optical artefacts may decrease the accuracy of measuring the proton beam range within the scintillator tank. The purpose of the current study was to 1) develop a geometric calibration system to accurately calculate physical distances within the liquid scintillator detector, taking into account optical artefacts; and 2) assess the accuracy, consistency, and robustness of proton beam range measurement using the liquid scintillator detector with our geometric calibration system. The range of the proton beam was measured with the calibrated liquid scintillator system and was compared to the nominal range. Measurements were made on three different days to evaluate the setup robustness from day to day, and three sets of measurements were made for each day to evaluate the consistency from delivery to delivery. All proton beam ranges measured using the liquid scintillator system were within half a millimeter of the nominal range. The delivery-to-delivery standard deviation of the range measurement was 0.04 mm, and the day-to-day standard deviation was 0.10 mm. In addition to the accuracy and robustness demonstrated by these results when our geometric calibration system was used, the liquid scintillator system allowed the range of all 94 proton beams to be measured in just two deliveries, making the liquid scintillator detector a perfect tool for range measurement of spot scanning proton beams.

show abstract

3D reconstruction of scintillation light emission from proton pencil beams using limited viewing angles—a simulation study

Cited by 15 publications

References 26 publications

Three‐dimensional gamma criterion for patient‐specific quality assurance of spot scanning proton beams

Three‐dimensional gamma criterion for patient‐specific quality assurance of spot scanning proton beams

Performance characterization of a 3D liquid scintillation detector for discrete spot scanning proton beam systems

Fast range measurement of spot scanning proton beams using a volumetric liquid scintillator detector

Contact Info

Product

Resources

About