Patterns of patient movement during frameless image-guided radiosurgery

Murphy, Martin J.; Chang, Steven D.; Gibbs, Iris C.; Le, Quynh Thu; Hai, Jenny; Kim, Daniel; Martin, David P.; Adler, John R.

doi:10.1016/s0360-3016(02)04597-2

Cited by 139 publications

(77 citation statements)

References 4 publications

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“…It was acknowledged (14) that with X‐ray–based technology, it is difficult to predict the residual target errors for individual patients before actual treatment delivery. A suggestion was made (14) , (26) to use more frequent imaging during the first fraction and then, depending on residual motion distribution, to adopt patient‐specific imaging frequency. Murphy et al (26) also noted that many patients exhibit systematic drifts in head position and that large (

> 2 mm

) position shifts are somewhat concentrated in a subset of the patient population that moves more often and by a greater amount than does the average patient.…”

Section: Discussionmentioning

confidence: 99%

“…A suggestion was made (14) , (26) to use more frequent imaging during the first fraction and then, depending on residual motion distribution, to adopt patient‐specific imaging frequency. Murphy et al (26) also noted that many patients exhibit systematic drifts in head position and that large (

> 2 mm

) position shifts are somewhat concentrated in a subset of the patient population that moves more often and by a greater amount than does the average patient. That finding further underscores the potential benefit of assigning patient‐specific, rather than population‐based, PTV margins—particularly for a system with relatively infrequent imaging such as Novalis.…”

Section: Discussionmentioning

confidence: 99%

“…As a tool to study patient‐specific motion, X‐ray imaging is useful chiefly for managing treatment times or for customizing PTV margins for fractionated treatments on a specific type of radiosurgery system. In addition, it was reported (26) that the patient motion and registration errors resulting from algorithm fluctuation around the optimal solution could not always be separated. Acquisition of robust motion statistics based on X‐ray imaging before treatment is not practical.…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Simulation of intrafraction motion and overall geometric accuracy of a frameless intracranial radiosurgery process

Feygelman

Walker

Chinnaiyan

et al. 2008

J Applied Clin Med Phys

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We conducted a comprehensive evaluation of the clinical accuracy of an image‐guided frameless intracranial radiosurgery system. All links in the process chain were tested. Using healthy volunteers, we evaluated a novel method to prospectively quantify the range of target motion for optimal determination of the planning target volume (PTV) margin. The overall system isocentric accuracy was tested using a rigid anthropomorphic phantom containing a hidden target. Intrafraction motion was simulated in 5 healthy volunteers. Reinforced head‐and‐shoulders thermoplastic masks were used for immobilization. The subjects were placed in a treatment position for 15 minutes (the maximum expected time between repeated isocenter localizations) and the six‐degrees‐of‐freedom target displacements were recorded with high frequency by tracking infrared markers. The markers were placed on a customized piece of thermoplastic secured to the head independently of the immobilization mask. Additional data were collected with the subjects holding their breath, talking, and deliberately moving. As compared with fiducial matching, the automatic registration algorithm did not introduce clinically significant errors (<0.3 mm difference). The hidden target test confirmed overall system isocentric accuracy of ≤1 mm (total three‐dimensional displacement). The subjects exhibited various patterns and ranges of head motion during the mock treatment. The total displacement vector encompassing 95% of the positional points varied from 0.4 mm to 2.9 mm. Pre‐planning motion simulation with optical tracking was tested on volunteers and appears promising for determination of patient‐specific PTV margins. Further patient study is necessary and is planned. In the meantime, system accuracy is sufficient for confident clinical use with 3 mm PTV margins.PACS number: 87.53.Ly

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> 2 mm

) position shifts are somewhat concentrated in a subset of the patient population that moves more often and by a greater amount than does the average patient.…”

Section: Discussionmentioning

confidence: 99%

> 2 mm

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Simulation of intrafraction motion and overall geometric accuracy of a frameless intracranial radiosurgery process

Feygelman

Walker

Chinnaiyan

et al. 2008

J Applied Clin Med Phys

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show abstract

“…Residual motion errors for image-guided treatments also tend to increase, because patients tend to move more often if they are immobilized for a longer time [ 7 ]. This in turn increases the uncertainty of treatment delivery, which needs to be considered in the design of the PTV treatment margin.…”

Section: Treatment Delivery Timementioning

confidence: 99%

Planning and Dosimetry for Stereotactic Body Radiotherapy

Dieterich

2014

Stereotactic Body Radiotherapy

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Planning for SBRT is characterized by the need to create high dose gradients from target to critical structures in the vicinity. Since SBRT is a relatively new fi eld, appropriate DVH constraints are still under development in clinical trials and single-center studies.The effect of residual motion such as deformation, rotation and residual respiratory motion has to be considered to determine appropriate ITV and PTV margins. SBRT targets such as lung are located in areas of the body with large tissue inhomogeneities. Treatment algorithms must be capable of modeling these inhomogeneities appropriately to generate a dose calculation which is close to the delivered dose. Planner skill has traditionally played a large role in designing high quality treatment plans with optimum target coverage and tissue sparing. Data mining of existing plans and the use of plan libraries is being explored to aid the treatment planner in standardizing planning approaches to more consistently fi nd the optimum dose distribution. To ensure a close match between plan dose calculations and delivered dose calculations, the dosimetry of small fi elds must be well understood and modelled in the treatment planning system. The small fi elds and sharp dose gradients pose more stringent challenges for patient-specifi c SBRT QA. Keywords IntroductionTreatment planning for stereotactic radiosurgery is very diverse in that it can range from using the same planning techniques as conventional IMRT (Intensity Modulated Radiation Therapy) with the only difference being in the dose-fractionation scheme and the technical constraints of delivery, to

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“…Nevertheless, a thermoplastic mask still restricts natural head motion and may be found psychologically confining for some patients. It has been reported that even with the mask, the patient's head can still drift from left to right (due to rotation about the fulcrum of the back of the skull), leading to systematic drift of targets inside the brain away from the initial setup position of up to 2 mm in certain cases (Murphy et al 2003). This may lead to treatment interruption for the purpose of performing intrafraction alignment in order to ensure target coverage (Murphy 2009).…”

Section: Introductionmentioning

confidence: 99%

Development of a frameless stereotactic radiosurgery system based on real-time 6D position monitoring and adaptive head motion compensation

Wiersma¹,

Wen

Sadinski

et al. 2009

Phys. Med. Biol.

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Stereotactic radiosurgery delivers radiation with great spatial accuracy. To achieve sub-millimeter accuracy for intracranial SRS, a head ring is rigidly fixated to the skull to create a fixed reference. For some patients, the invasiveness of the ring can be highly uncomfortable and not well tolerated. In addition, placing and removing the ring requires special expertise from a neurosurgeon, and patient setup time for SRS can often be long. To reduce the invasiveness, hardware limitations and setup time, we are developing a system for performing accurate head positioning without the use of a head ring. The proposed method uses real-time 6D optical position feedback for turning on and off the treatment beam (gating) and guiding a motorcontrolled 3D head motion compensation stage. The setup consists of a central control computer, an optical patient motion tracking system and a 3D motion compensation stage attached to the front of the LINAC couch. A styrofoam head cast was custom-built for patient support and was mounted on the compensation stage. The motion feedback of the markers was processed by the control computer, and the resulting motion of the target was calculated using a rigid body model. If the target deviated beyond a preset position of 0.2 mm, an automatic position correction was performed with stepper motors to adjust the head position via the couch mount motion platform. In the event the target deviated more than 1 mm, a safety relay switch was activated and the treatment beam was turned off. The feasibility of the concept was tested using five healthy volunteers. Head motion data were acquired with and without the use of motion compensation over treatment times of 15 min. On average, test subjects exceeded the 0.5 mm tolerance 86% of the time and the 1.0 mm tolerance 45% of the time without motion correction.

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Patterns of patient movement during frameless image-guided radiosurgery

Cited by 139 publications

References 4 publications

Simulation of intrafraction motion and overall geometric accuracy of a frameless intracranial radiosurgery process

Simulation of intrafraction motion and overall geometric accuracy of a frameless intracranial radiosurgery process

Planning and Dosimetry for Stereotactic Body Radiotherapy

Development of a frameless stereotactic radiosurgery system based on real-time 6D position monitoring and adaptive head motion compensation

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