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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adopted for patient positioning but suffer from systematic positioning errors induced by probe pressure.Previously unpublished material on tissue tracking systems and robotic probe manipulators under development by our group is also included.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 Previously unpublished material on tissue tracking systems and robotic probe manipulators under development by our group is also included.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

Comparison of US images and tracking performance with beam off and on, reproduced from Schlosser et al.Comparison of US images and tracking performance with beam off and on, reproduced from Schlosser et al. [58] (a) True object displacement versus computed displacement using cross-correlation. (b) Tracked circular object indicated within ultrasound images at two displacement values. The square indicates the location of the tracked object based on the manually selected target template.
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FIG5: Comparison of US images and tracking performance with beam off and on, reproduced from Schlosser et al.Comparison of US images and tracking performance with beam off and on, reproduced from Schlosser et al. [58] (a) True object displacement versus computed displacement using cross-correlation. (b) Tracked circular object indicated within ultrasound images at two displacement values. The square indicates the location of the tracked object based on the manually selected target template.

Mentions: Studies examining the effect of radiation on US image quality have produced dissimilar conclusions, although all have demonstrated the feasibility of US ultrasound to track anatomical motion in real-time. Hsu, et al. [79] used an Acuson 128/XP US scanner to image stationary and moving phantoms while operating an Elekta SL25 LINAC. The experiment found the US images to be affected by a periodic noise at a frequency identical to the pulsing frequency of the treatment machine; however, this noise was found to have minimal effects on the precision of the tracking algorithm. Schlosser, et al. [58] found no spatial or temporal interference patterns in US images of a phantom acquired with a 3.5 MHz Interson 2D single-element probe during LINAC beam operation. Additionally, no significant difference in tracking accuracy was found between beam-off and beam-on cases (Figure 5). US imaging interference from a LINAC likely depends on the specifics of the US imaging system being used; for example, modern systems with improved shielding may better reject radio-frequency interference from the LINAC.


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

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

Comparison of US images and tracking performance with beam off and on, reproduced from Schlosser et al.Comparison of US images and tracking performance with beam off and on, reproduced from Schlosser et al. [58] (a) True object displacement versus computed displacement using cross-correlation. (b) Tracked circular object indicated within ultrasound images at two displacement values. The square indicates the location of the tracked object based on the manually selected target template.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

FIG5: Comparison of US images and tracking performance with beam off and on, reproduced from Schlosser et al.Comparison of US images and tracking performance with beam off and on, reproduced from Schlosser et al. [58] (a) True object displacement versus computed displacement using cross-correlation. (b) Tracked circular object indicated within ultrasound images at two displacement values. The square indicates the location of the tracked object based on the manually selected target template.
Mentions: Studies examining the effect of radiation on US image quality have produced dissimilar conclusions, although all have demonstrated the feasibility of US ultrasound to track anatomical motion in real-time. Hsu, et al. [79] used an Acuson 128/XP US scanner to image stationary and moving phantoms while operating an Elekta SL25 LINAC. The experiment found the US images to be affected by a periodic noise at a frequency identical to the pulsing frequency of the treatment machine; however, this noise was found to have minimal effects on the precision of the tracking algorithm. Schlosser, et al. [58] found no spatial or temporal interference patterns in US images of a phantom acquired with a 3.5 MHz Interson 2D single-element probe during LINAC beam operation. Additionally, no significant difference in tracking accuracy was found between beam-off and beam-on cases (Figure 5). US imaging interference from a LINAC likely depends on the specifics of the US imaging system being used; for example, modern systems with improved shielding may better reject radio-frequency interference from the LINAC.

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