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Ultrasound Imaging in Radiation Therapy: From Interfractional to Intrafractional Guidance.

Western C, Hristov D, Schlosser J - Cureus (2015)

Bottom Line: With the proliferation of hypofractionated radiotherapy treatment regimens, such as stereotactic body radiation therapy (SBRT), interfractional and intrafractional imaging technologies are becoming increasingly critical to ensure safe and effective treatment delivery.Interfractional US guidance systems have been commercially adopted for patient positioning but suffer from systematic positioning errors induced by probe pressure.Previously unpublished material on tissue tracking systems and robotic probe manipulators under development by our group is also included.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Mechanical Engineering, Stanford University.

ABSTRACT
External beam radiation therapy (EBRT) is included in the treatment regimen of the majority of cancer patients. With the proliferation of hypofractionated radiotherapy treatment regimens, such as stereotactic body radiation therapy (SBRT), interfractional and intrafractional imaging technologies are becoming increasingly critical to ensure safe and effective treatment delivery. Ultrasound (US)-based image guidance systems offer real-time, markerless, volumetric imaging with excellent soft tissue contrast, overcoming the limitations of traditional X-ray or computed tomography (CT)-based guidance for abdominal and pelvic cancer sites, such as the liver and prostate. Interfractional US guidance systems have been commercially adopted for patient positioning but suffer from systematic positioning errors induced by probe pressure. More recently, several research groups have introduced concepts for intrafractional US guidance systems leveraging robotic probe placement technology and real-time soft tissue tracking software. This paper reviews various commercial and research-level US guidance systems used in radiation therapy, with an emphasis on hardware and software technologies that enable the deployment of US imaging within the radiotherapy environment and workflow. Previously unpublished material on tissue tracking systems and robotic probe manipulators under development by our group is also included.

No MeSH data available.


Related in: MedlinePlus

Respiratory analysis for the liver.(a) Baseline blood vessel and nearby target. (b) Linear predictive models. (c) Respiratory signals and model errors. Reproduced from Schlosser[63]
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FIG4: Respiratory analysis for the liver.(a) Baseline blood vessel and nearby target. (b) Linear predictive models. (c) Respiratory signals and model errors. Reproduced from Schlosser[63]

Mentions: Errors based on the external surrogate model was larger than 2.0 mm on average, at times exceeding 4.0 mm while the mean error was less than 1.0 mm using the internal US surrogate model. Pearson correlation coefficient averaged 0.83 between external surrogate motion and target motion, in contrast to 0.97 between internal surrogate and target. The study thus demonstrated superior tracking of target motion using US to monitor the displacement of an internal feature when compared with tracking of an external surrogate. Results are illustrated in Figure 4.


Ultrasound Imaging in Radiation Therapy: From Interfractional to Intrafractional Guidance.

Western C, Hristov D, Schlosser J - Cureus (2015)

Respiratory analysis for the liver.(a) Baseline blood vessel and nearby target. (b) Linear predictive models. (c) Respiratory signals and model errors. Reproduced from Schlosser[63]
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4494460&req=5

FIG4: Respiratory analysis for the liver.(a) Baseline blood vessel and nearby target. (b) Linear predictive models. (c) Respiratory signals and model errors. Reproduced from Schlosser[63]
Mentions: Errors based on the external surrogate model was larger than 2.0 mm on average, at times exceeding 4.0 mm while the mean error was less than 1.0 mm using the internal US surrogate model. Pearson correlation coefficient averaged 0.83 between external surrogate motion and target motion, in contrast to 0.97 between internal surrogate and target. The study thus demonstrated superior tracking of target motion using US to monitor the displacement of an internal feature when compared with tracking of an external surrogate. Results are illustrated in Figure 4.

Bottom Line: With the proliferation of hypofractionated radiotherapy treatment regimens, such as stereotactic body radiation therapy (SBRT), interfractional and intrafractional imaging technologies are becoming increasingly critical to ensure safe and effective treatment delivery.Interfractional US guidance systems have been commercially adopted for patient positioning but suffer from systematic positioning errors induced by probe pressure.Previously unpublished material on tissue tracking systems and robotic probe manipulators under development by our group is also included.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Mechanical Engineering, Stanford University.

ABSTRACT
External beam radiation therapy (EBRT) is included in the treatment regimen of the majority of cancer patients. With the proliferation of hypofractionated radiotherapy treatment regimens, such as stereotactic body radiation therapy (SBRT), interfractional and intrafractional imaging technologies are becoming increasingly critical to ensure safe and effective treatment delivery. Ultrasound (US)-based image guidance systems offer real-time, markerless, volumetric imaging with excellent soft tissue contrast, overcoming the limitations of traditional X-ray or computed tomography (CT)-based guidance for abdominal and pelvic cancer sites, such as the liver and prostate. Interfractional US guidance systems have been commercially adopted for patient positioning but suffer from systematic positioning errors induced by probe pressure. More recently, several research groups have introduced concepts for intrafractional US guidance systems leveraging robotic probe placement technology and real-time soft tissue tracking software. This paper reviews various commercial and research-level US guidance systems used in radiation therapy, with an emphasis on hardware and software technologies that enable the deployment of US imaging within the radiotherapy environment and workflow. Previously unpublished material on tissue tracking systems and robotic probe manipulators under development by our group is also included.

No MeSH data available.


Related in: MedlinePlus