Monitoring external beam radiotherapy using real‐time beam visualization

Jenkins, C; Naczynski, Dominik J.; Yu, Amy S.; Li, Xing

doi:10.1118/1.4901255

Cited by 26 publications

(32 citation statements)

References 32 publications

(30 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…System self-calibration and experimental validation will also be described in detail. This work builds upon our previous work in developing a real-time beam visualization system for monitoring external beam radiotherapy (Jenkins et al 2015). …”

Section: Introductionmentioning

confidence: 97%

Automating quality assurance of digital linear accelerators using a radioluminescent phosphor coated phantom and optical imaging

Jenkins

Naczynski

et al. 2016

Phys. Med. Biol.

Self Cite

View full text Add to dashboard Cite

Purpose To develop a novel strategy to automate the predominantly manual process of mechanical and geometric tests in routine quality assurance (QA) of digital linear accelerator (LINAC). Methods The autonomous QA system consists of three parts: (1) a customized phantom coated with radioluminescent material; (2) an optical imaging system capable of visualizing the incidence of the radiation beam, light field or lasers on the phantom; and (3) software to process the captured signals. The radioluminescent phantom, which enables visualization of the radiation beam on the same surface as the light field and lasers, was placed on the couch and imaged while a predefined treatment plan was delivered from the LINAC. The captured images were then processed to self-calibrate the system and perform measurements for evaluating light field/radiation coincidence, jaw position indicators, cross-hair centering, treatment couch position indicators and localizing laser alignment. System accuracy was probed by intentionally introducing errors and by comparing with current practice. The accuracy of self-calibration was evaluated by examining measurement repeatability under fixed and variable phantom setups. Results The integrated system was able to automatically collect, analyze and report the results for all tests. The average difference between introduced and measured errors was 0.13 mm. The system was shown to be consistent with current techniques. Measurement variability increased slightly from 0.1 mm to 0.2 mm when the phantom setup was varied, but no significant difference in the mean measurement value was detected. Total measurement time was less than 10 minutes for all tests as a result of automation. Conclusions The integrated QA system succeeded in autonomously performing mechanical alignment tests specified by TG-142. The system’s unique features of a phosphor-coated phantom and fully automated, operator independent self-calibration offer the potential to streamline the QA process for modern LINACs.

show abstract

Section: Introductionmentioning

confidence: 97%

Automating quality assurance of digital linear accelerators using a radioluminescent phosphor coated phantom and optical imaging

Jenkins

Naczynski

et al. 2016

Phys. Med. Biol.

Self Cite

View full text Add to dashboard Cite

show abstract

“…The methods demonstrated in the current work are similar to those reported by Jenkins et al where thin (0.8 mm) scintillating silicone films were used for beam visualization. 13 However, we have demonstrated commercially available inks (Available for $15/30 mL) can be directly painted or transferred onto skin-phantoms covering a large area. This application demonstrates how currently used tattoo-based fiducial markings could utilize the same inks over a larger area, and applied in a semi-permanent topical manner, to visualize entrance and exit beams for field delivery verification.…”

Section: Discussionmentioning

confidence: 99%

“…The absolute pixel resolution attained by the imaging system under normal room illumination is 1.4 mm, whereas the resolution observed during the x-ray pulse is approximately 1.6 mm, which is slightly larger than the average deviation reported by Jenkins (mean: 0.5 mm, max: 2.0 mm) using a similar experimental setup. 13 The observed resolution is likely limited by camera detection optics, as the resolution degrades only slightly between room illumination and x-ray excitation. In situations where portal imaging is used for alignment, which is common in low-to middle-income countries, average treatment variations of 3 mm have been shown.…”

Section: Discussionmentioning

confidence: 99%

Imaging luminescent tattoo inks for direct visualization of linac and cobalt irradiation

et al. 2020

View full text Add to dashboard Cite

Purpose: Tattoo fiducials are commonly used in radiotherapy patient alignment, and recent studies have examined the use of UV-excited luminescent tattoo ink as a cosmetic substitute to make these visible under UV illumination. The goal of this study was to show how luminescent tattoo inks could be excited with MV radiation and imaged during beam delivery for direct visualization of field position. Methods: A survey of nine UV-sensitive tattoo inks with various emission spectra were investigated using both UV and MV excitation. Images of liquid solutions were collected under MV excitation using an intensified-CMOS imager. Solid skin-simulating phantoms were imaged with both surfacepainted ink and in situ tattooing during dose delivery by both a clinical linear accelerator and cobalt-60 source. Results: The UV inks have peak fluorescence emission ranging from approximately 440 to 600 nm with lifetimes near 11-16 ls. The luminescence intensity is approximately 6x higher during the x-ray pulse than after the pulse, however, the signal-to-noise is only approximately twice as large. Spatial resolution for imaging was achieved at 1.6 mm accuracy in a skin test phantom. Optical filtering allows for continuous imaging using a cobalt source and provides a mechanism to discriminate ink colors using a monochromatic image sensor. Conclusions: This study demonstrates how low-cost inks can be used as fiducial markers and imaged both using time-gated and continuous modes during MV dose delivery. Phantom studies demonstrate the potential application of real-time field verification. Further studies are required to understand if this technique could be used as a tool for radiation dosimetry.

show abstract

“…Flex-RLI: Flex-RLI scintillators were prepared by thoroughly mixing gadolinium oxysulfide:terbium (GOS:Tb) powder (Phosphor Technology; Stevenage, England) with a silicone elastomer (Dow Corning; Auburn, MI) in a 1:1 mass ratio. 13 The mixture was then poured into a Petri dish and allowed to solidify under room temperature. The scintillator was white and opaque to light [see Fig.…”

Section: B Optimal Imaging Modalitiesmentioning

confidence: 99%

“…This method utilizes a flexible scintillator, which can loosely conform to body contours. 13 We hypothesize that flex-RLI can enhance the SBR of 18 F-FDG-avid tumors compared to that of RLI based on geometric considerations. First, the flexible scintillator may enhance tumor signal by minimizing the air gap between the scintillator and the tumor, thus allowing for maximal interaction of beta particles with the scintillator.…”

Section: Introductionmentioning

confidence: 99%