The correlation between internal and external markers for abdominal tumors: Implications for respiratory gating

Gierga, David P.; Brewer, Johanna; Sharp, G; Betke, Margrit; Willett, Christopher G.; Chen, George T.Y.

doi:10.1016/j.ijrobp.2004.12.013

Cited by 198 publications

(124 citation statements)

References 15 publications

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“…Note that the development of our framework is independent of the data used, be it data collected with an external marker placed on the abdomen during breathing or internal tumour motion data obtained from a fluoroscopic marker. Ideally, in the optimization, a treatment planner would use data describing actual tumour motion induced by breathing, or external data plus the appropriate parameters to correlate internal motion to the external marker (Vedam et al 2003, Gierga et al 2005, Tsunashima et al 2004.…”

Section: From Patient Data To a Model Of Uncertaintymentioning

confidence: 99%

A robust approach to IMRT optimization

2006

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Managing uncertainty is a major challenge in radiation therapy treatment planning, including uncertainty induced by intrafraction motion, which is particularly important for tumours in the thorax and abdomen. Common methods to account for motion are to introduce a margin or to convolve the static dose distribution with a motion probability density function. Unlike previous work in this area, our development does not assume that the patient breathes according to a fixed distribution, nor is the patient required to breathe the same way throughout the treatment. Despite this generality, we create a robust optimization framework starting from the convolution method that is robust to fluctuations in breathing motion, yet spares healthy tissue better than a margin solution. We describe how to generate the data for our model using breathing motion data and we test our model on a computer phantom using data from real patients. In our numerical results, the robust solution delivers approximately 38% less dose to the healthy tissue than the margin solution, while providing the same level of protection against breathing uncertainty.

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Section: From Patient Data To a Model Of Uncertaintymentioning

confidence: 99%

A robust approach to IMRT optimization

2006

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“…This model is subsequently used to guide a γ-radiation source. That this correlation indeed exists has been evaluated before [3,11]. Currently, this model is built using 10-20 measurements of internal fiducials acquired during the first couple of breathing cycles.…”

Section: Introductionmentioning

confidence: 99%

Correlating Chest Surface Motion to Motion of the Liver Using ε-SVR – A Porcine Study

Ernst

Martens

Schlichting

et al. 2009

Medical Image Computing and Computer-Assisted Intervention – MICCAI 2009

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Abstract. In robotic radiosurgery, the compensation of motion of internal organs is vital. This is currently done in two phases: an external surrogate signal (usually active optical markers placed on the patient's chest) is recorded and subsequently correlated to an internal motion signal obtained using stereoscopic X-ray imaging. This internal signal is sampled very infrequently to minimise the patient's exposure to radiation. We have investigated the correlation of the external signal to the motion of the liver in a porcine study using ε-support vector regression. IR LEDs were placed on the swines' chest. Gold fiducials were placed in the swines' livers and were recorded using a two-plane X-ray system. The results show that a very good correlation model can be built using ε-SVR, in this test clearly outperforming traditional polynomial models by at least 45 and as much as 74 %. Using multiple markers simultaneously can increase the new model's accuracy.

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“…To use these techniques in clinical practice, a correlation between external markers or sensors and internal tumor motion is needed. Many researchers 7 , 8 , 9 have shown a correlation between the external marker and the internal tumor motion, and have reported that the maximum variations between the internal motion and external markers were about 10 mm. Although a correlation between external markers and internal tumor positions exists, external markers cannot be used as an adequate indicator to determine the internal tumor position in some patients.…”

Section: Introductionmentioning

confidence: 97%

Evaluation of a combined respiratory‐gating system comprising the TrueBeam linear accelerator and a new real‐time tumor‐tracking radiotherapy system: a preliminary study

Shiinoki

Kawamura

Uehara

et al. 2016

J Applied Clin Med Phys

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A combined system comprising the TrueBeam linear accelerator and a new real‐time, tumor‐tracking radiotherapy system, SyncTraX, was installed in our institution. The goals of this study were to assess the capability of SyncTraX in measuring the position of a fiducial marker using color fluoroscopic images, and to evaluate the dosimetric and geometric accuracy of respiratory‐gated radiotherapy using this combined system for the simple geometry. For the fundamental evaluation of respiratory‐gated radiotherapy using SyncTraX, the following were performed: 1) determination of dosimetric and positional characteristics of sinusoidal patterns using a motor‐driven base for several gating windows; 2) measurement of time delay using an oscilloscope; 3) positional verification of sinusoidal patterns and the pattern in the case of a lung cancer patient; 4) measurement of the half‐value layer (HVL in mm AL), effective kVp, and air kerma, using a solid‐state detector for each fluoroscopic condition, to determine the patient dose. The dose profile in a moving phantom with gated radiotherapy having a gating window ≤4 mm was in good agreement with that under static conditions for each photon beam. The total time delay between TrueBeam and SyncTraX was <227 ms for each photon beam. The mean of the positional tracking error was <0.4 mm for sinusoidal patterns and for the pattern in the case of a lung cancer patient. The air‐kerma rates from one fluoroscopy direction were 1.93±0.01, 2.86±0.01, 3.92±0.04, 5.28±0.03, and 6.60±0.05 mGy/min for 70, 80, 90, 100, and 110 kV X‐ray beams at 80 mA, respectively. The combined system comprising TrueBeam and SyncTraX could track the motion of the fiducial marker and control radiation delivery with reasonable accuracy; therefore, this system provides significant dosimetric improvement. However, patient exposure dose from fluoroscopy was not clinically negligible.PACS number(s): 87.53.Bn, 87.55.km, 87.55.Qr

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The correlation between internal and external markers for abdominal tumors: Implications for respiratory gating

Cited by 198 publications

References 15 publications

A robust approach to IMRT optimization

A robust approach to IMRT optimization

Correlating Chest Surface Motion to Motion of the Liver Using ε-SVR – A Porcine Study

Evaluation of a combined respiratory‐gating system comprising the TrueBeam linear accelerator and a new real‐time tumor‐tracking radiotherapy system: a preliminary study

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