Alterations in normal liver doses due to organ motion

Roşu, Mihaela; Dawson, Laura A.; Balter, James M.; McShan, Daniel L.; Lawrence, Theodore S.; Haken, Randall K. Ten

doi:10.1016/j.ijrobp.2003.08.025

Cited by 63 publications

(40 citation statements)

References 30 publications

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“…30 The dose predicted by the plan using 3D CT may not accurately reflect the dose delivered to the patient because of random setup variation and the breathinginduced organ motion. 31,32 The concern is raised whether the plan designed based on the free-breathing CT using ITV approach can predict real dose delivered to the patients for the liver patients. As shown in Fig.…”

Section: Discussionmentioning

confidence: 99%

Proton Radiotherapy for Liver Tumors: Dosimetric Advantages Over Photon Plans

et al. 2008

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Section: Discussionmentioning

confidence: 99%

Proton Radiotherapy for Liver Tumors: Dosimetric Advantages Over Photon Plans

et al. 2008

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“…8 The Calypso system ͑Calypso Medical Technologies, Inc., Seattle, WA͒ is capable of real-time tracking of the intrafraction prostate motion, 9 therefore the actual dose delivered in the presence of intrafraction motion can be evaluated by convolving the static dose distribution with the motion probability density function ͑PDF͒. Similar approaches have been reported previously [10][11][12][13][14][15][16][17][18] to account for setup errors and organ motion in other tumor sites. The conventional convolution approach uses the PDF generated by population-based motion data, 15 e.g., an entire fraction, an entire treatment course of a patient, or even an entire patient population.…”

Section: Introductionmentioning

confidence: 96%

Quantifying the interplay effect in prostate IMRT delivery using a convolution‐based method

Chetty

Solberg

2008

Medical Physics

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The authors present a segment-based convolution method to account for the interplay effect between intrafraction organ motion and the multileaf collimator position for each particular segment in intensity modulated radiation therapy ͑IMRT͒ delivered in a step-and-shoot manner. In this method, the static dose distribution attributed to each segment is convolved with the probability density function ͑PDF͒ of motion during delivery of the segment, whereas in the conventional convolution method ͑"average-based convolution"͒, the static dose distribution is convolved with the PDF averaged over an entire fraction, an entire treatment course, or even an entire patient population. In the case of IMRT delivered in a step-and-shoot manner, the average-based convolution method assumes that in each segment the target volume experiences the same motion pattern ͑PDF͒ as that of population. In the segment-based convolution method, the dose during each segment is calculated by convolving the static dose with the motion PDF specific to that segment, allowing both intrafraction motion and the interplay effect to be accounted for in the dose calculation. Intrafraction prostate motion data from a population of 35 patients tracked using the Calypso system ͑Calypso Medical Technologies, Inc., Seattle, WA͒ was used to generate motion PDFs. These were then convolved with dose distributions from clinical prostate IMRT plans. For a single segment with a small number of monitor units, the interplay effect introduced errors of up to 25.9% in the mean CTV dose compared against the planned dose evaluated by using the PDF of the entire fraction. In contrast, the interplay effect reduced the minimum CTV dose by 4.4%, and the CTV generalized equivalent uniform dose by 1.3%, in single fraction plans. For entire treatment courses delivered in either a hypofractionated ͑five fractions͒ or conventional ͑Ͼ30 fractions͒ regimen, the discrepancy in total dose due to interplay effect was negligible.

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“…Although several studies have examined the respiratory motion of tumors in the lung (8)(9)(10)(11)(12) and infradiaphragmatic organs (13)(14)(15), the literature describing esophageal tumor motion Reprint requests to: Noah C. Choi is limited. Lorchel et al (16) have reported measurements of esophageal tumor motion by acquiring CT scans during inspiratory and expiratory breath-hold for a series of 8 patients (16).…”

Section: Introductionmentioning

confidence: 99%