Target localization for post‐prostatectomy patients using CT and ultrasound image guidance

Paskalev, K; Feigenberg, Steven J.; Jacob, Rojymon; McNeeley, Shawn; Horwitz, Eric M.; Price, Robert A.; Ma, Charlie; Pollack, Alan

doi:10.1120/jacmp.v6i4.2137

Cited by 17 publications

(8 citation statements)

References 27 publications

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“…The mean movement calculated in this study is similar to that shown in previous studies . Table shows the mean magnitude and standard deviations of the prostate bed motion calculated by other groups who have also used CBCT imaging .…”

Section: Discussionsupporting

confidence: 86%

Prostate bed motion may cause geographic miss in post‐prostatectomy image‐guided intensity‐modulated radiotherapy

et al. 2013

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Variability was seen in all planes for the movement of both surgical clips. The greatest movement occurred in the anterior-posterior plane in the upper prostate bed, which could cause geographic miss of treatment delivery. The variability in the movement of the superior and inferior clips indicates a prostate bed tilt that would be difficult to correct with standard online matching techniques. This creates a strong argument for using anisotropic planning target volume margins in post-prostatectomy radiotherapy.

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Section: Discussionsupporting

confidence: 86%

Prostate bed motion may cause geographic miss in post‐prostatectomy image‐guided intensity‐modulated radiotherapy

et al. 2013

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“…Despite the increasing popularity of image guided techniques for the intact prostate cancer patient, few studies are specifically relevant to the post‐prostatectomy patient. Paskalev et al demonstrated that ultrasound localization may be limited in its ability to accurately define the treatment volume 9 . Schiffner et al , using electronic portal imaging and implanted fiducial markers noted set‐up errors could be corrected using their on‐line technique 13 .…”

Section: Discussionmentioning

confidence: 99%

“…Previous studies have used ultrasound, megavoltage CT, kilovoltage (kV) CT imaging and implanted fiducial marker techniques to determine movement of the prostate bed, target volume, bladder and rectum 8–14 . Techniques for correcting patient position relative to soft tissue position are described only for the ultrasound imaging techniques.…”

Section: Introductionmentioning

confidence: 99%

“…Techniques for correcting patient position relative to soft tissue position are described only for the ultrasound imaging techniques. Ultrasound typically carries large measurement uncertainties and unless combined with additional imaging techniques such as CT 9 may only be useful to correct for large target volume displacements. Schiffner et al , using electronic portal imaging and implanted fiducial markers, noted movement of the tumour bed could be corrected using their on‐line technique 13 .…”

Section: Introductionmentioning

confidence: 99%

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Verification of target position in the post‐prostatectomy cancer patient using cone beam CT

Haworth¹,

Paneghel

Herschtal

et al. 2009

J Med Imag Rad Onc

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We present the results of a pilot study designed to investigate methods that may be applied to develop a patient position correction protocol for the post-prostatectomy patient receiving radiotherapy. Imaging was carried out with cone beam CT (CBCT) to investigate its suitability for detecting changes in rectal and bladder volumes and movements of these organs relative to the treatment planning CT. Eligible patients were imaged daily during the first week of treatment and weekly thereafter. Surrogate explanatory variables, including distance from the isocentre to the anterior rectum and bladder length, were tested for their potential to substitute for contouring entire organs and predict for changes in coverage of the planning treatment volume (PTV) by the 95% isodose (PTV95) and the maximum dose delivered to 50% of the rectal volume (RECTD50). The PTV defined on the CBCT images was larger than that defined on the planning CT and resulted in a decrease in the PTV95. Bladder length correlated with bladder volume and changes in bladder volume were associated with a decrease in PTV95. Rectal volumes changed randomly during treatment. There was a trend for the rectum to move anteriorly as treatment progressed. CBCT may be used to define the PTV, rectum and bladder though the reason for an apparent increase in PTV on CBCT requires further investigation. The bladder length and distance to the anterior rectal wall are potential surrogate explanatory variables. Further studies will be designed to test values of these surrogates that predict the need for a change in isocentre position.

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“…Several investigators have published their experiences with various localization techniques, including conebeam CT (CBCT) (4), ultrasound (5,6), orthogonal imaging with alignment to surgical clips (7), or implanted gold seeds (8). While these studies have described the characteristics of inter-fractional displacement of the prostate bed relative to bony anatomy, there is as of yet, no detailed investigation of prostate bed movement during treatment delivery.…”

Section: Introductionmentioning

confidence: 99%

Prostate Bed Motion during Intensity Modulated Radiotherapy Treatment

Klayton¹,

Price²,

Buyyounouski³

et al. 2011

International Journal of Radiation Oncology*Biology*Physics

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Purpose/Objective(s)-Conformal radiation therapy in the post-prostatectomy setting requires accurate setup and localization of the prostatic fossa. In this series, we report prostate bed localization and motion characteristics using data collected from implanted radiofrequency transponders.Materials and Methods-The Calypso 4D Localization System uses three implanted radiofrequency transponders for daily target localization and real-time tracking throughout a course of radiation therapy. We reviewed the localization and tracking reports of 20 patients who received ultrasound-guided placement of Calypso transponders within the prostate bed prior to a course of intensity modulated radiation therapy at Fox Chase Cancer Center.Results-At localization, prostate bed displacement relative to bony anatomy exceeded 5 mm in 9% of fractions in the Anterior-Posterior (A-P) direction, and 21% of fractions in the SuperiorInferior (S-I) direction. The three-dimensional vector length from skin marks to Calypso alignment exceeded 1 cm in 24% of all 652 fractions with available setup data. During treatment, the target exceeded the 5 mm tracking limit for at least 30 seconds in 11% of all fractions, generally in the A-P or S-I directions. In the A-P direction, target motion was twice as likely to move posteriorly, towards the rectum, than anteriorly. 15% of all treatments were interrupted for repositioning, and 70% of patients were repositioned at least once during their treatment course.Conclusion-Set-up errors and motion of the prostatic fossa during radiotherapy are nontrivial, leading to potential undertreatment of target and excess normal tissue toxicity if not taken into account during treatment planning. Localization and real-time tracking of the prostate bed via implanted Calypso transponders can be used to improve the accuracy of plan delivery.

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Target localization for post‐prostatectomy patients using CT and ultrasound image guidance

Cited by 17 publications

References 27 publications

Prostate bed motion may cause geographic miss in post‐prostatectomy image‐guided intensity‐modulated radiotherapy

Prostate bed motion may cause geographic miss in post‐prostatectomy image‐guided intensity‐modulated radiotherapy

Verification of target position in the post‐prostatectomy cancer patient using cone beam CT

Prostate Bed Motion during Intensity Modulated Radiotherapy Treatment

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