Tracking Accuracy of a Real-Time Fiducial Tracking System for Patient Positioning and Monitoring in Radiation Therapy

Shchory, T; Schifter, Dan; Lichtman, R.; Neustadter, David M.; Corn, Benjamin W.

doi:10.1016/j.ijrobp.2010.01.067

Cited by 25 publications

(16 citation statements)

References 16 publications

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“…An alternative type of surrogate first described by Shchory et al 47 was clinically evaluated by de Kruijf et al, 48 who used radioactive iridium-192 as an implanted tracer in 20 patients. They report this approach as feasible and safe.…”

Section: Other Types Of Markermentioning

confidence: 99%

Fiducial marker guided prostate radiotherapy: a review

O’Neill¹,

Jain²,

Hounsell³

et al. 2016

The British Journal of Radiology

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Image-guided radiotherapy (IGRT) is an essential tool in the accurate delivery of modern radiotherapy techniques. Prostate radiotherapy positioned using skin marks or bony anatomy may be adequate for delivering a relatively homogeneous whole-pelvic radiotherapy dose, but these surrogates are not reliable when using reduced margins, dose escalation or hypofractionated stereotactic radiotherapy. Fiducial markers (FMs) for prostate IGRT have been in use since the 1990s. They require surgical implantation and provide a surrogate for the position of the prostate gland. A variety of FMs are available and they can be used in a number of ways. This review aimed to establish the evidence for using prostate FMs in terms of feasibility, implantation procedures, types of FMs used, FM migration, imaging modalities used and the clinical impact of FMs. A search strategy was defined and a literature search was carried out in Medline. Inclusion and exclusion criteria were applied, which resulted in 50 articles being included in this review. The evidence demonstrates that FMs provide a more accurate surrogate for the position of the prostate than either external skin marks or bony anatomy. A combination of FM alignment and soft-tissue analysis is currently the most effective and widely available approach to ensuring accuracy in prostate IGRT. FM implantation is safe and well tolerated. FM migration is possible but minimal. Standardization of all techniques and procedures in relation to the use of prostate FMs is required. Finally, a clinical trial investigating a non-surgical alternative to prostate FMs is introduced.

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Section: Other Types Of Markermentioning

confidence: 99%

Fiducial marker guided prostate radiotherapy: a review

O’Neill¹,

Jain²,

Hounsell³

et al. 2016

The British Journal of Radiology

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“…Several real-time tumor localization imaging modalities have been investigated; for example, ultrasonography (4), megavoltage (MV) imaging (5), combined MV and kV (6), Calypso EM guidance (7), and Navotek radioactive fiducial implant (8). However, some of these techniques are either still under development, not readily available, or are expensive.…”

Section: Introductionmentioning

confidence: 99%

Kilovoltage Intrafraction Monitoring for Prostate Intensity Modulated Arc Therapy: First Clinical Results

Booth

Poulsen

et al. 2012

International Journal of Radiation Oncology*Biology*Physics

104

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Summary Most cancer radiation therapy accelerators purchased today have gantry-mounted imagers, typically used to image the patient prior to treatment. We imaged prostate cancer patients during their treatment. Combining images with marker segmentation software and a 2- to 3-dimensional reconstruction method, we were able to measure prostate motion during the treatment to within submillimeter accuracy. Because intrafraction prostate monitoring method uses widely available clinical equipment, intratreatment prostate motion monitoring could become routine. Purpose Most linear accelerators purchased today are equipped with a gantry-mounted kilovoltage X-ray imager which is typically used for patient imaging prior to therapy. A novel application of the X-ray system is kilovoltage intrafraction monitoring (KIM), in which the 3-dimensional (3D) tumor position is determined during treatment. In this paper, we report on the first use of KIM in a prospective clinical study of prostate cancer patients undergoing intensity modulated arc therapy (IMAT). Methods and Materials Ten prostate cancer patients with implanted fiducial markers undergoing conventionally fractionated IMAT (RapidArc) were enrolled in an ethics-approved study of KIM. KIM involves acquiring kV images as the gantry rotates around the patient during treatment. Post-treatment, markers in these images were segmented to obtain 2D positions. From the 2D positions, a maximum likelihood estimation of a probability density function was used to obtain 3D prostate trajectories. The trajectories were analyzed to determine the motion type and the percentage of time the prostate was displaced ≥3, 5, 7, and 10 mm. Independent verification of KIM positional accuracy was performed using kV/MV triangulation. Results KIM was performed for 268 fractions. Various prostate trajectories were observed (ie, continuous target drift, transient excursion, stable target position, persistent excursion, high-frequency excursions, and erratic behavior). For all patients, 3D displacements of ≥3, 5, 7, and 10 mm were observed 5.6%, 2.2%, 0.7% and 0.4% of the time, respectively. The average systematic accuracy of KIM was measured at 0.46 mm. Conclusions KIM for prostate IMAT was successfully implemented clinically for the first time. Key advantages of this method are (1) submillimeter accuracy, (2) widespread applicability, and (3) a low barrier to clinical implementation. A disadvantage is that KIM delivers additional imaging dose to the patient.

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“…A variety of methods exist for monitoring the position of the prostate during treatment, including megavoltage (MV) imaging,6 ultrasound,7 combined MV and kilovoltage (kV) imaging,8 Calypso electromagnetic guidance,9 the BrainLAB ExacTrac x‐ray system,10 the Cyberknife platform,11, 12, 13 and Navotek radioactive fiducials 14. Several of these methods require additional equipment not available on a standard linear accelerator, are costly, and require further expertise to implement.…”

Section: Introductionmentioning

confidence: 99%

Real‐time intrafraction prostate motion during linac based stereotactic radiotherapy with rectal displacement

Legge

Nguyen

et al. 2017

J Applied Clin Med Phys

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BackgroundKilovoltage Intrafraction Monitoring (KIM) is a method which determines the three‐dimensional position of the prostate from two‐dimensional kilovoltage (kV) projections taken during linac based radiotherapy treatment with real‐time feedback. Rectal displacement devices (RDDs) allow for improved rectal dosimetry during prostate cancer treatment. This study used KIM to perform a preliminary investigation of prostate intrafraction motion observed in patients with an RDD in place.MethodsTen patients with intermediate to high‐risk prostate cancer were treated with a Rectafix RDD in place during two boost fractions of 9.5–10 Gy delivered using volumetric modulated arc therapy (VMAT) on Clinac iX and Truebeam linacs. Two‐dimensional kV projections were acquired during treatment. KIM software was used following treatment to determine the displacement of the prostate over time. The displacement results were analyzed to determine the percentage of treatment time the prostate spent within 1 mm, between 1 and 2 mm, between 2 and 3 mm and greater than 3 mm from its initial position.Results KIM successfully measured displacement for 19 prostate stereotactic boost fractions. The prostate was within 1 mm of its initial position for 84.8%, 1–2 mm for 14%, 2–3 mm 1.2% and ≥3 mm only 0.4% of the treatment time.ConclusionsIn this preliminary study using KIM, KIM was successfully used to measure prostate intrafraction motion, which was found to be small in the presence of a rectal displacement device.Trial registrationThe Hunter New England Human Research Ethics Committee reference number is 14/08/20/3.01.

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Tracking Accuracy of a Real-Time Fiducial Tracking System for Patient Positioning and Monitoring in Radiation Therapy

Cited by 25 publications

References 16 publications

Fiducial marker guided prostate radiotherapy: a review

Fiducial marker guided prostate radiotherapy: a review

Kilovoltage Intrafraction Monitoring for Prostate Intensity Modulated Arc Therapy: First Clinical Results

Real‐time intrafraction prostate motion during linac based stereotactic radiotherapy with rectal displacement

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