Guide to clinical use of electronic portal imaging

Herman, Michael; Kruse, Jon J.; Hagness, C.R.

doi:10.1120/jacmp.v1i2.2645

Cited by 28 publications

(14 citation statements)

References 99 publications

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“…Clinical use of electronic portal imaging devices has been addressed by TG58 74 and is described widely in the literature. 17,[75][76][77] Recommended QA tests from the TG-58 report are incorporated in Table VI, though updated to account for on-boardimaging tests. However, details of the test contents, such as the dose rate to be checked for imaging quality, the energy, and the calibration distances, should be determined specifically for each type of EPID and for each individual institution.…”

Section: Iid5a Planar MV Imaging (Portal Imagers)mentioning

confidence: 99%

Task Group 142 report: Quality assurance of medical acceleratorsa)

et al. 2009

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The task group ͑TG͒ for quality assurance of medical accelerators was constituted by the American Association of Physicists in Medicine's Science Council under the direction of the Radiation Therapy Committee and the Quality Assurance and Outcome Improvement Subcommittee. The task group ͑TG-142͒ had two main charges. First to update, as needed, recommendations of Table II of the AAPM TG-40 report on quality assurance and second, to add recommendations for asymmetric jaws, multileaf collimation ͑MLC͒, and dynamic/virtual wedges. The TG accomplished the update to TG-40, specifying new test and tolerances, and has added recommendations for not only the new ancillary delivery technologies but also for imaging devices that are part of the linear accelerator. The imaging devices include x-ray imaging, photon portal imaging, and cone-beam CT. The TG report was designed to account for the types of treatments delivered with the particular machine. For example, machines that are used for radiosurgery treatments or intensity-modulated radiotherapy ͑IMRT͒ require different tests and/or tolerances. There are specific recommendations for MLC quality assurance for machines performing IMRT. The report also gives recommendations as to action levels for the physicists to implement particular actions, whether they are inspection, scheduled action, or immediate and corrective action. The report is geared to be flexible for the physicist to customize the QA program depending on clinical utility. There are specific tables according to daily, monthly, and annual reviews, along with unique tables for wedge systems, MLC, and imaging checks. The report also gives specific recommendations regarding setup of a QA program by the physicist in regards to building a QA team, establishing procedures, training of personnel, documentation, and end-to-end system checks. been considerably expanded as compared with the original TG-40 report and the recommended tolerances accommodate differences in the intended use of the machine functionality ͑non-IMRT, IMRT, and stereotactic delivery͒.

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Section: Iid5a Planar MV Imaging (Portal Imagers)mentioning

confidence: 99%

Task Group 142 report: Quality assurance of medical acceleratorsa)

et al. 2009

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“…Localization accuracy is essential for these treatments,3 with various motion management strategies being employed. Lung tumors or implanted fiducials in the liver4 are often visible on cine MV imaging using the electronic portal imaging device 5. When possible, cine imaging using the MV beam during 3D conformal SBRT is one of the best methods to verify target localization; this is because the tumor is visualized during the treatment in the beam's eye view.…”

Section: Introductionmentioning

confidence: 99%

An in‐house protocol for improved flood field calibration of TrueBeam FFF cine imaging

Faught

Yin

Adamson

2017

J Applied Clin Med Phys

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PurposeTrueBeams equipped with the 40 × 30 cm2 Electronic Portal Imaging Devices (EPIDs) are prone to image saturation at the image center when used with flattening filter free (FFF) photon energies. While cine imaging during treatment may not saturate because the beam is attenuated by the patient, the flood field calibration is affected when the standard calibration procedure is followed. Here, we describe the hardware and protocol to achieve improved image quality for this model of TrueBeam EPID.Materials & methodsA stainless steel filter of uniform thickness was designed to have sufficient attenuation to avoid panel saturation. The cine imaging flood field calibration was acquired with the filter in place for the FFF energies under the standard calibration geometry (SID = 150 cm). Image quality during MV cine was assessed with & without the modified flood field calibration using a low contrast resolution phantom and an anthropomorphic phantom.ResultsWhen the flood field is acquired without the filter in place, a pixel gain artifact is clearly present in the image center which may be mis‐attributed to panel saturation in the subject image. At the image center, the artifact obscured all low contrast inserts and was also visible on the anthropomorphic phantom. Using the filter for flood field calibration eliminates the artifact.ConclusionTrueBeams equipped with the 40 × 30 cm2 IDU can utilize a modified flood field calibration procedure for FFF photon energies that improves image quality for cine MV imaging.

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“…( 20 , 21 ) Using an EPID, online digital port images can be efficiently captured and analyzed before, or even during, every treatment session. For patients who have no particular setup difficulties, this high level of monitoring may be unnecessary.…”

Section: Introductionmentioning

confidence: 99%

Patient‐specific daily pretreatment setup protocol using electronic portal imaging for radiation therapy

Wittmer

Pisansky

Kruse

et al. 2005

J Applied Clin Med Phys

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The purpose of this study was to evaluate electronic portal imaging (EPI) as a means of identifying and correcting field displacement in patients with problematic external beam radiotherapy setups. Fourteen patients with problematic setups were identified for pretreatment daily EPI beam monitoring as part of a physician‐directed therapist intervention protocol. Pretreatment EPIs were used to realign fields as necessary to bring the setup within the physician‐prescribed tolerance level. For comparison, daily EPIs were available for 12 control patients who had no particular setup difficulties and for whom online beam realignment was not made. Anatomy‐matching software was used to measure setup variation along medial‐lateral, superior‐inferior, and anterior‐posterior axes. Online field realignment yielded a significant false(p=0.001false) improvement when comparing initial and final setup variations. The mean standard deviation of setup displacement averaged over three axes was reduced from 6.4 mm to 3.1 mm after realignment. The final variation of protocol patients was comparable to that of control patients. In conclusion, EPI provided effective means to perform online beam realignment in a group of difficult‐to‐position patients. This procedure resulted in a reduction in setup displacement that was statistically significant, clinically relevant, and approached that of a more typical patient group.PACS number: 87.53.Oq

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Guide to clinical use of electronic portal imaging

Cited by 28 publications

References 99 publications

Task Group 142 report: Quality assurance of medical acceleratorsa)

Task Group 142 report: Quality assurance of medical acceleratorsa)

An in‐house protocol for improved flood field calibration of TrueBeam FFF cine imaging

Patient‐specific daily pretreatment setup protocol using electronic portal imaging for radiation therapy

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