Real-time 3D surface imaging for patient positioning in radiotherapy

Smith, N.; Meir, Ivan; Hale, Graham; Howe, Robert B.; Johnson, L. Scott; Edwards, P. R.; Hawkes, DJ; Bidmead, M.; Landau, David

doi:10.1016/s0360-3016(03)00982-9

Cited by 17 publications

(5 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To date, several motion monitoring systems are available and are in clinical use in conventional radiotherapy. 38,[61][62][63][64][65][66][67][68][69][70][71][72][73] In principle, their performance seems sufficient for beam gating of scanned particle beams even if respiratory motion is measured on the patient's surface. As long as the main objective of beam gating is elimination of detrimental interplay effects, the correlation between external and internal motions is most likely not relevant.…”

Section: Ivb Beam Gatingmentioning

confidence: 99%

Respiratory motion management in particle therapy

2010

View full text Add to dashboard Cite

Clinical outcomes of charged particle therapy are very promising. Currently, several dedicated centers that use scanning beam technology are either close to clinical use or under construction. Since scanned beam treatments of targets that move with respiration most likely result in marked local over- and underdosage due to interplay of target motion and dynamic beam application, dedicated motion mitigation techniques have to be employed. To date, the motion mitigation techniques, rescanning, beam gating, and beam tracking, have been proposed and tested in experimental studies. Rescanning relies on repeated irradiations of the target with the number of particles reduced accordingly per scan to statistically average local misdosage. Specific developments to prohibit temporal correlation between beam scanning and target motion will be required to guarantee adequate averaging. For beam gating, residual target motion within gating windows has to be mitigated in order to avoid local misdosage. Possibly the most promising strategy is to increase the overlap of adjacent particle pencil beams laterally as well as longitudinally to effectively reduce the sensitivity against small residual target motion. The most conformal and potentially most precise motion mitigation technique is beam tracking. Individual particle pencil beams have to be adapted laterally as well as longitudinally according to the target motion. Within the next several years, it can be anticipated that rescanning as well as beam gating will be ready for clinical use. For rescanning, treatment planning margins that incorporate the full extent of target motion as well as motion induced density variations in the beam paths will result in reduced target conformity of the applied dose distributions. Due to the limited precision of motion monitoring devices, it seems likely that beam gating will be used initially to mitigate interplay effects only but not to considerably decrease treatment planning margins. Then, in the next step, beam gating, based on more accurate motion monitoring systems, provides the possibility to restore target conformity as well as steep dose gradients due to reduced treatment planning margins. Accurate motion monitoring systems will be required for beam tracking. Even though beam tracking has already been successfully tested experimentally, full clinical implementation requires direct feedback of the actual target position in quasireal time to the treatment control system and can be anticipated to be several more years ahead.

show abstract

Section: Ivb Beam Gatingmentioning

confidence: 99%

Respiratory motion management in particle therapy

2010

View full text Add to dashboard Cite

show abstract

“…Smith et al 7 compared a prototype of the 3D surface imaging system with an optical system based on fiducial markers. ͑Optotrak, Northern Digital Inc., Waterloo, Ontario, Canada͒.…”

Section: Accuracy Of Recommended Patient Realignmentmentioning

confidence: 99%

“…The most common approaches are laser interferometry, 3 reflect-ive marker photogrammetry, 4,5 and digital speckle photogrammetry. 6,7 Photogrammetry has been used to study ͑i͒ shape of structures ͑teeth͒; ͑ii͒ changes in shape over time ͑growth, treatment͒; and ͑iii͒ body motion ͑sports or respiration related͒. 2 Our application focuses on the use of close-range photogrammetry with speckle projection to aid the setup of partial breast irradiation ͑PBI͒ patients.…”

Section: Introductionmentioning

confidence: 99%

A phantom evaluation of a stereo‐vision surface imaging system for radiotherapy patient setup

et al. 2005

View full text Add to dashboard Cite

External beam irradiation requires precise positioning of the target relative to the treatment planning coordinate system. A three-dimensional (3D) surface imaging system for patient positioning has recently been installed in one of our linear accelerator (linac) rooms. The device utilizes close-range photogrammetry to generate a 3D model of the patient's surface. This geometric model can be made to look like a digital camera image if wrapped with a gray-level image (texture mapping) that shows surface coloration. The system is calibrated to the linac coordinate system and has been designed as a patient setup device. To reproduce patient position in fractionated radiotherapy, the daily patient surface model is registered to a previously recorded reference surface. Using surface registration, the system calculates the rigid-body transformation that minimizes the distance between the treatment and the reference surface models in a region-of-interest (ROI). This transformation is expressed as a set of new couch coordinates at which the patient position best matches with the reference data. If respiratory motion is a concern, the surface can be obtained with a gated acquisition at a specified phase of the respiratory cycle. To analyze the accuracy of the system, we performed several experiments with phantoms to assess stability, alignment accuracy, precision of the gating function, and surface topology. The reproducibility of surface measurements was tested for periods up to 57 h. Each recorded frame was registered to the reference surface to calculate the required couch adjustment. The system stability over this time period was better than 0.5 mm. To measure the accuracy of the system to detect and quantify patient shift relative to a reference image, we compared the shift detected by the surface imaging system with known couch transitions in a phantom study. The maximum standard deviation was 0.75 mm for the three translational degrees of freedom, and less than 0.1 degrees for each rotation. Surface model precision was tested against computed tomography (CT)-derived surface topology. The root-mean-square rms of the distance between the surfaces was 0.65 mm, excluding regions where beam hardening caused artifacts in the CT data. Measurements were made to test the gated acquisition mode. The time-dependent amplitude was measured with the surface imaging system and an established respiratory gating system based on infrared (IR)-marker detection. The measured motion trajectories from both systems were compared to the known trajectory of the stage. The standard deviations of the amplitude differences to the motor trajectory were 0.04 and 0.15 mm for the IR-marker system and the 3D surface imaging system, respectively. A limitation of the surface-imaging device is the frame rate of 6.5 Hz, because rapid changes of the motion trajectory cannot be detected. In conclusion, the system is accurate and sufficiently stable to be used in the clinic. The errors computed when comparing the surface model with CT geometry were submi...

show abstract

“…Constraints of a radiotherapy room (mainly distance between patient and 3D surface sensor), can not allows the use of mechanical contact sensor; in other hand stereovision and passive triangulation are not suitable because of the less accuracy of these systems (in a range of centimeters) and illuminations conditions of radiotherapy room [9]. Finally active triangulation sensors are innocuous and represent actually a compromise between accuracy and acquisition time.…”

Section: Methodsmentioning

confidence: 99%

Non-invasive tumor localization by 3D registration of range sensor and computer tomography images.

Posada-Gómez

Alor-Hernandez

Garcia-Martinez

et al. 2007

Eighth Mexican International Conference on Current Trends in Computer Science (ENC 2007)

View full text Add to dashboard Cite

This paper describes a patient positioning method that allows a non-invasive localization of tumors in the field of conformal radiotherapy for the treatment of cancers located in the head. The proposed methodology uses computer tomography and range sensor images of the patient's head; on the one hand tomography data has information of tumor localization related to the patient's head and on the other hand range sensor images has information of patient's face localization into the treatment's room.A 3D multimodality registration of computer tomography and range sensor images and the calibration of range sensor at radiotherapy treatment room avoid the use of stereotactic frame for patient's positioning. Tests performed with human data proved that the registration algorithm is accurate (0.1mm mean distance between homologous points) and robust even for facial expression changes.

show abstract

Real-time 3D surface imaging for patient positioning in radiotherapy

Cited by 17 publications

References 0 publications

Respiratory motion management in particle therapy

Respiratory motion management in particle therapy

A phantom evaluation of a stereo‐vision surface imaging system for radiotherapy patient setup

Non-invasive tumor localization by 3D registration of range sensor and computer tomography images.

Contact Info

Product

Resources

About