Dose-Free Monitoring of Radiotherapy Treatments With Scattered Photons: First Experimental Results at a 6-MV Linac

Simoes, Hugo; Cunha, Micaela; Pinto, M.; Goncalves, J.F.; Sampaio, Liliana; Ferreira, Ricardo J O; Saraiva, Henrique M.; Barbeiro, A.R.; Capela, M.; Ferreira, B.; Fonte, P.; Ghithan, Sharif; Leal, Antonio; Lopes, Maria do Carmo; Martins, P.; Crespo, Paulo

doi:10.1109/tns.2013.2265137

Cited by 11 publications

(2 citation statements)

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“…Compton scatter imaging is a well‐studied modality in the context of tomographic imaging and other quantitative modalities . While its application in a clinical setting has so far not materialized, in the context of tumor tracking several promising proposals are currently being pursued that make use of the radiation scattered by the patient during the treatment, either using the megavoltage x‐ray beam as the source of the scattered radiation or a kilovoltage fan beam to obtain a cross‐sectional view of the patient, in both works employing pinhole or multihole collimators to form the image. In this work, we have shown that the radiation scattered by the patient when irradiated with an imaging kilovoltage x‐ray beam can be used in conjunction with the obtained primary image to determine spatial information about internal objects in the imaged subject.…”

Section: Discussionmentioning

confidence: 99%

Directional scatter imaging for the stereoscopic tracking of fiducial markers in a single kV exposure

Garnica-Garza

2017

Medical Physics

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Section: Discussionmentioning

confidence: 99%

Directional scatter imaging for the stereoscopic tracking of fiducial markers in a single kV exposure

Garnica-Garza

2017

Medical Physics

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“…First experiments have been carried out with single-pixel scanning along a heterogeneous muscle-like phantom [1] together with different Monte Carlo simulations [2], [3] performed at LIP in close collaboration with the University of Coimbra, the Portuguese Oncology Centers of Porto and Coimbra, and the Radiotherapy Department of Coimbra University Hospital Center. This proposed imaging technique consists in operating a dedicated X-ray detection system Manuscript received March 4, 2017; revised July 4, 2017. specially adapted to collect selected patient-scattered radiation, aiming at: (1) imaging the tumor region with the patient already positioned for treatment (so-called onboard imaging), and/or (2) imaging in real-time the anatomic region under irradiation, including the tumor. The detection can be achieved by positioning one or more collimator-based, 1D detector systems parallel to the beam axis, hence collecting such orthogonal rays.…”

Section: Introductionmentioning

confidence: 99%

Patient Compton Scattered Radiation for Monitoring Prostate Radiotherapy with Gold Fiducial Markers: A Simulation Study

Lopes¹,

Simoes²,

Travassos³

et al. 2017

IJPMBS

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Abstract-Orthogonal ray imaging is a new low-dose imaging technology under study aimed at assist externalbeam radiotherapy (EBRT) treatments. It consists in detecting radiation scattered in the patient and emitted perpendicularly to the incident beam. Such radiation can be collected by positioning a multi-sliced, collimator-based, 1D detector system parallel to the beam axis, hence collecting such orthogonal rays, or by using a pinhole-like detector system positioned above or below the patient. This system can potentially be useful for on-board imaging, or real-time EBRT monitoring. In terms of prostate cancer irradiation, the use of implanted fiducial markers allows a more precise verification of the gland position relative to the bony anatomy. The prostate target normally exhibits intra-and interfraction motion induced by the daily variation in rectal and bladder filling. In order to solve this issue, three gold fiducial markers are inserted into the prostate. In the present study, the imaging capability provided by utilizing X-rays escaping the patient/fiducial markers orthogonally in respect to the incoming beam direction is studied by GEANT4 simulation. The results allow concluding that the signal provided by such X-rays is highly coincident with the position of the gold fiducial markers, even in situations where these have been deviated by as little as 3.0 mm.  Index Terms-image-guided radiotherapy, OrthoCT, Monte Carlo simulation, gold fiducial markers, prostate cancer

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A light-guide optimization for proof-of-principle of a megavoltage orthogonal ray imaging prototype

Simoes

Crespo

2015

2015 IEEE 4th Portuguese Meeting on Bioengineering (ENBENG)

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Radiotherapy (RT) is nowadays, after surgery, the most frequently used cancer treatment. Modern RT techniques provide increasingly higher conformality, a potential invaluable clinical benefit to the patient. Consequently, patient misalignments and changing internal anatomy (e.g. tissue swelling, edema, inflammation or tumor shrinkage/growth) are also becoming more critical since higher conformality may equally represent a higher risk of target underdosage or organ-at-risk overdosage. Therefore, state-of-the-art image-guided radiotherapy (IGRT) is the modern technique that aims at providing feedback to the radiation oncologist in regard to these matters, sometimes at the cost of increased dosage or treatment fraction time (e.g. kilo and megavoltage cone-beam computed tomography), other times providing insufficient clinical information. Our group is investigating a novel imaging system especially designed for assisting RT treatments. Such system, termed OrthoCT, consists in operating a dedicated X-ray detection system specially built for collecting selected patientscattered radiation. Our team has shown by simulation [1,2] and experiments [2, 3] that collecting such radiation allows for a rotation-free, 3D imaging of the inner morphology of the target (patient). The rotation-free and low dose 3D imaging capability of OrthoCT renders it very attractive due to its usefulness for so-called "on-board" patient imaging. A small-scale, bi-dimensional system is under construction for proof-of-principle validation. It consists of 4 crystals lines separated by collimator slices. Each crystal line is composed by 50 gadolinium oxyorthosilicate (GSO) crystals with a front

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Dose-Free Monitoring of Radiotherapy Treatments With Scattered Photons: First Experimental Results at a 6-MV Linac

Cited by 11 publications

References 14 publications

Directional scatter imaging for the stereoscopic tracking of fiducial markers in a single kV exposure

Directional scatter imaging for the stereoscopic tracking of fiducial markers in a single kV exposure

Patient Compton Scattered Radiation for Monitoring Prostate Radiotherapy with Gold Fiducial Markers: A Simulation Study

A light-guide optimization for proof-of-principle of a megavoltage orthogonal ray imaging prototype

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