Patient positioning in the proton radiotherapy era (original) (raw)
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ReviewPatient positioning in the proton radiotherapy era
2015
The main hindrance to the diffusion of proton therapy facilities is the high cost for gantry installations. An alternative technical option is provided by fixed-beam treatment rooms, where the patient is rotated and translated in space with a robotic arm solution to enable beam incidence from various angles. The technological efforts based on robotic applications made up to now for patient positioning in proton beam facilities are described here, highlighting their limitations and perspectives. Review There is currently an increasing interest in proton therapy in the world and the number of proton therapy facilities is rapidly increasing; mostly owing to the fact that physicians acknowledge that even the best current technique of X-ray therapy (intensity modulated proton therapy, IMRT) are still far from maximizing the therapeutic gain, i.e. increasing the local tumour control and decreasing the morbidity in healthy tissues. The concern about late effects for "low" doses t...
International Journal of Radiation Oncology*Biology*Physics, 2008
Purpose: To describe a remote positioning system for accurate and efficient proton radiotherapy treatments. Methods and Materials: To minimize positioning time in the treatment room (and thereby maximize beam utility), we have adopted a method for remote patient positioning, with patients positioned and imaged outside the treatment room. Using a CT scanner, positioning is performed using orthogonal topograms with the measured differences to the reference images being used to define daily corrections to the patient table in the treatment room. Possible patient movements during transport and irradiation were analyzed through periodic acquisition of posttreatment topograms. Systematic and random errors were calculated for this daily positioning protocol and for two off-line protocols. The potential time advantage of remote positioning was assessed by computer simulation. Results: Applying the daily correction protocol, systematic errors calculated over all patients (n = 94) were below 0.6 mm, whereas random errors were below 1.5 mm and 2.5 mm, respectively, for bite-block and for mask immobilization. Differences between pre-and posttreatment images were below 2.8 mm (SD) in abdominal/pelvic region, and below 2.4 mm (SD) in the head. Retrospective data analysis for a subset of patients revealed that off-line protocols would be significantly less accurate. Computer simulations showed that remote positioning can increase patient throughput up to 30%. Conclusions: The use of a daily imaging and correction protocol based on a ''remote'' CT could reduce positioning errors to below 2.5 mm and increase beam utility in the treatment room. Patient motion between imaging and treatment were not significant. Ó
Patient positioning for protontherapy using a proton range telescope
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1995
A method is described for imaging integrated density along the beam path in phantoms that makes use of high energy proton beams. An application of the technique is in the positioning of patients in a proton therapy radiation facility. It makes use of a proton range telescope for density variation and X-Y detectors for planar positioning. The principle of the method was tested at a proton energy of 66 MeV. Good visual quality is seen in the tests. The measurements are compared with detailed Monte Carlo simulations, and good agreement is found. We apply the simulations to high energy proton beams (245 MeV) and show that the method should provide good visual quality and sensitivity for positioning at the higher energies necessary for whole body therapy.
Journal of applied clinical medical physics / American College of Medical Physics, 2010
Large area, shallow fields are well suited to proton therapy. However, due to beam production limitations, such volumes typically require multiple matched fields. This is problematic due to the relatively narrow beam penumbra at shallow depths compared to electron and photon beams. Therefore, highly accurate dose planning and delivery is required. As the dose delivery includes shifting the patient for matched fields, accuracy at the 1-2 millimeter level in patient positioning is also required. This study investigates the dosimetric accuracy of such proton field matching by an innovative robotic patient positioner system (RPPS). The dosimetric comparisons were made between treatment planning system calculations, radiographic film and ionization chamber measurements. The results indicated good agreement amongst the methods and suggest that proton field matching by a RPPS is accurate and efficient.
Commissioning and initial experience with the first clinical gantry-mounted proton therapy system
Journal of applied clinical medical physics, 2016
The purpose of this study is to describe the comprehensive commissioning process and initial clinical experience of the Mevion S250 proton therapy system, a gantry-mounted, single-room proton therapy platform clinically implemented in the S. Lee Kling Proton Therapy Center at Barnes-Jewish Hospital in St. Louis, MO, USA. The Mevion S250 system integrates a compact synchrocyclotron with a C-inner gantry, an image guidance system and a 6D robotic couch into a beam delivery platform. We present our commissioning process and initial clinical experience, including i) CT calibration; ii) beam data acquisition and machine characteristics; iii) dosimetric commissioning of the treatment planning system; iv) validation through the Imaging and Radiation Oncology Core credentialing process, including irradiations on the spine, prostate, brain, and lung phantoms; v) evaluation of localization accuracy of the image guidance system; and vi) initial clinical experience. Clinically, the system opera...
Applied Radiation and Isotopes, 2004
A flexible technique for positioning patients in fixed orientation radiation fields such as those used in neutron capture therapy (NCT) has been developed. The positioning technique employs reference points marked on the patient in combination with a 3D digitizer to determine the beam entry point and a template fitted to the patient's head is used to determine the proper beam orientation. A coordinate transformation between the CT image data and reference points on the patient determined by a least squares algorithm based on singular value decomposition is used to map the beam entry point from the planning system onto the patient. The technique was validated in a phantom study where the mean error in entry point placement was 1.3 mm. Five glioblastoma multiforme patients have been treated with NCT using this positioning technique.
Optimising the verification of patient positioning in proton beam therapy
2005
... Rep. [8] O. Ecabert and J. Thiran, "Adaptive hough transform for the detection of natural shapes under weak affine transformations," Pattern Recognition Letters, vol, 25, pp. 1411-1419, 2004. [9] S. Clippe, D. Sarrut, C.Malet, S. Miguet, C. Ginestet, and C. Carrie, "Patient setup ...
Robotic Systems for Radiation Therapy
Medical robotics is an exciting and relatively new field. Robotics plays an important role in medical engineering. Medical robots were initially used in the 1980s, in the field of urology. Robotic arms were developed and used for prostate resection. They can also be highly specialized and assist in diagnosing and treating patients. While there is still much more work to be done, using robots can enhance medical treatments in terms of both the quality and accessibility of care. Using robots can help reduce human error and bring highly specialized information to remote areas without requiring physicians' direct intervention. In radiation therapy, high-energy radiation from x-rays, gamma rays, neutrons, and other sources has been used to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy), or it may come from radioactive materials placed in the body near cancer cells (internal radiation therapy, implant radiation, or brachytherapy). The usage of robotic systems to improve the cancer treatment outcome is a new field. This field overlaps with electronics, computer science, artificial intelligence, mechatronics, nanotechnology, and bioengineering. For this purpose, robots can be used in medical facilities to perform different tasks such as delivering radiation sources, real-time tumor tracking during radiation delivery or external beam delivery. The only product in the market for robotic radiotherapy is CyberKnife Robotic Radiosurgery System. The robotic system has provision for so-called real-time tracking during beam delivery. The device itself is a 6MV linear accelerator mounted on a six degree-of-freedom (DOF) Keller und Knappich Augsburg (KUKA) industrial robot. This system has real-time image-guided control. Consequently, there is a significantly long time delay (about 200 ms) between the acquisition of tumor coordinates and repositioning to the linear accelerator. The CyberKnife-KUKA robot with linear accelerator end-effector is suited for radiation therapy to any body sites. Its field size is restricted to the limited geometry of 12 discrete circular fields ranging from 5mm to 60mm in diameter. Therefore, the workspace is confined and the radiation therapy community has not fully embraced the idea of using an industrial articulated robotic manipulator yet. The details about CyberKnife robotic system are not included in this chapter. Consequently, the basic idea is to present the novel research results in the field of robotic radiation therapy and its applications.
Physica Medica, 2020
This work aims to validate new 6D couch features and their implementation for seated radiotherapy in RayStation (RS) treatment planning system (TPS). Materials and methods: In RS TPS, new 6D couch features are (i) chair support device, (ii) patient treatment option of "Sitting: face towards the front of the chair", and (iii) patient support pitch and roll capabilities. The validation of pitch and roll was performed by comparing TPS generated DRRs with planar x-rays. Dosimetric tests through measurement by 2D ion chamber array were performed for beams created with varied scanning and treatment orientation and 6D couch rotations. For the implementation of 6D couch features for treatments in a seated position, the TPS and oncology information system (Mosaiq) settings are described for a commercial chair. An end-to-end test using an anthropomorphic phantom was performed to test the complete workflow from simulation to treatment delivery. Results: The 6D couch features were found to have a consistent implementation that met IEC 61712 standard. The DRRs were found to have an acceptable agreement with planar x-rays based on visual inspection. For dose map comparison between measured and calculated, the gamma index analysis for all the beams was >95% at a 3% dose-difference and 3 mm distance-to-agreement tolerances. For an end-to end-testing, the phantom was successfully set up at isocenter in the seated position and treatment was delivered. Conclusions: Chair-based treatments in a seated position can be implemented in RayStation through the use of newly released 6D couch features.