Use of an implanted marker and real-time tracking of the marker for the positioning of prostate and bladder cancers

Shimizu, Satoru; Shirato, Hiroki; Kitamura, Kei; Shinohara, Nobuo; Harabayashi, T.; Tsukamoto, Taiji; Koyanagi, Tomohiko; Miyasaka, Kazuo

doi:10.1016/s0360-3016(00)00809-9

Cited by 188 publications

(93 citation statements)

References 17 publications

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“…Our method using fiducial markers and two sets of fluoroscopy was also shown to be useful to reduce set-up error compared to the skin-based setting (5,13,15). In this study, we focused on intra-fraction displacement according to treatment time, from the beginning of each treatment session after the daily set-up procedure was finished.…”

Section: Discussionmentioning

confidence: 99%

“…The usefulness of fiducial markers such as radio-opaque materials or electromagnetic devices for the assessment of inter-fraction prostate displacement has also been well established (5)(6)(7)(8). Precise re-positioning using an IGRT technique with prostate markers has shown to be useful for reducing the margin of the planning target volume (5)(6)(7)(8).…”

Section: Introductionmentioning

confidence: 99%

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Use of Implanted Markers and Interportal Adjustment With Real-Time Tracking Radiotherapy System to Reduce Intrafraction Prostate Motion

Shimizu

Osaka

Shinohara

et al. 2011

International Journal of Radiation Oncology*Biology*Physics

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Purpose: Interportal adjustment was applied to patients with prostate cancer using three fiducial markers and two sets of fluoroscopy in a real-time tumor-tracking radiotherapy (RTRT) system. The incidence of table position adjustment required to keep intrafractional uncertainty within 2.0 mm was investigated in this study. Methods and Materials:The coordinates of the center of gravity of the three fiducial markers were measured at the start of every portal irradiation in intensity-modulated radiotherapy (IMRT) with seven ports. The table position was adjusted to the planned position if the discrepancy was larger than 2.0 mm in the anterior-posterior (AP), cranio-caudal (CC), or left-right (LR) directions. In total, we analyzed 4541 observations in 20 patients who received 70 Gy in 30 fractions (7.6 times a day in average). Results:The incidence of table position adjustment at 10 minutes from the initial set-up of each treatment was 14.2%, 12.3%, and 5.0% of the observations in the AP, CC, and LR directions, respectively. The accumulated incidence of the table position adjustment was significantly higher at 10 minutes compared to that at 2 minutes for AP (p=0.0033) and CC (p=0.0110) but not LR (p=0.4296). An adjustment greater than 5 mm was required at least once in the treatment period in 11 (55%) patients. Conclusions:Interportal adjustment of table position was required in more than 10% of portal irradiations during the 10-minute period after initial set-up to maintain treatment accuracy within 2.0 mm.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Use of Implanted Markers and Interportal Adjustment With Real-Time Tracking Radiotherapy System to Reduce Intrafraction Prostate Motion

Shimizu

Osaka

Shinohara

et al. 2011

International Journal of Radiation Oncology*Biology*Physics

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“…If the EPID images are acquired using respiration gating, the set-up margin can be substantially reduced, especially if the GTV can be seen on the images, which is a possibility with the ever-increasing improvement in EPID hardware and software. Furthermore, gating can be based on internal markers embedded in the tumour rather than an external respiration signal, 13,16,17,30 and thus the positional uncertainties can be substantially reduced.…”

Section: Introductionmentioning

confidence: 99%

Potential radiotherapy improvements with respiratory gating

Keall

Kini

Vedam

et al. 2002

Australas. Phys. Eng. Sci. Med.

148

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Gating is a relatively new and potentially useful therapeutic addition to external beam radiotherapy applied to regions affected by intra-fraction motion. The impact was of gating on treatment margins, image artifacts, and volume and positional accuracy was investigated by CT imaging of sinusoidally moving spheres. The motion of the spheres simulates target motion. During the CT imaging of dynamically moving spheres, gating reproduced the static volume to within 1%, whereas errors of over 20% were observed where gating was not used. Using a theoretical analysis of margins, gating alone or in combination with an electronic portal imaging device may allow a 2-11 mm reduction in the CTV to PTV margin, and thus less healthy tissue need be irradiated. Gating may allow a reduction of treatment margins, an improvement in image quality, and an improvement in positional and volumetric accuracy of the gross tumor volume.

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“…These results suggested that using the ExacTrac X‐ray 6D system can increase the localization accuracy for patients and may reduce the internal margin. Another study (14) investigated the difference in the marker position between manual setup using skin markers and setup using a fluoroscopic X‐ray system for the prostate. It reported that dislocation was decreased by less than 1 mm for the lateral, anteroposterior, and craniocaudal directions using the RTRT system.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of mechanical accuracy for couch‐based tracking system (CBTS)

Lee

Chang

Shim

et al. 2012

J Applied Clin Med Phys

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This study evaluated the mechanical accuracy of an in‐house–developed couch‐based tracking system (CBTS) according to respiration data. The overall delay time of the CBTS was calculated, and the accuracy, reproducibility, and loading effect of the CBTS were evaluated according to the sinusoidal waveform and various respiratory motion data of real patients with and without a volunteer weighing 75 kg. The root mean square (rms) error of the accuracy, the reproducibility, and the sagging measurements were calculated for the three axes (X, Y, and Z directions) of the CBTS. The overall delay time of the CBTS was 0.251 sec. The accuracy and reproducibility in the Z direction in real patient data were poor, as indicated by high rms errors. The results of the loading effect were within 1.0 mm in all directions. This novel CBTS has the potential for clinical application for tumor tracking in radiation therapy.PACS number: 87.55.ne

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Use of an implanted marker and real-time tracking of the marker for the positioning of prostate and bladder cancers

Cited by 188 publications

References 17 publications

Use of Implanted Markers and Interportal Adjustment With Real-Time Tracking Radiotherapy System to Reduce Intrafraction Prostate Motion

Use of Implanted Markers and Interportal Adjustment With Real-Time Tracking Radiotherapy System to Reduce Intrafraction Prostate Motion

Potential radiotherapy improvements with respiratory gating

Evaluation of mechanical accuracy for couch‐based tracking system (CBTS)

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