A radiographic and tomographic imaging system integrated into a medical linear accelerator for localization of bone and soft-tissue targets

Jaffray, David A.; Drake, Douglas G.; Moreau, M.; Martínez, Álvaro; Wong, John W.

doi:10.1016/s0360-3016(99)00118-2

Cited by 284 publications

(151 citation statements)

References 34 publications

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“…2,3 Exploration of CBCT technologies for use in radiation therapy guidance began in 1992, 4,5 followed by integration of the first CBCT imaging system into the gantry of a linear accelerator in 1999. 6 The first CBCT system became commercially available for dentomaxillofacial imaging in 2001 (NewTom QR DVT 9000; Quantitative Radiology, Verona, Italy). Comparatively low dosing requirements and a relatively compact design have also led to intense interest in surgical planning and intraoperative CBCT applications, particularly in the head and neck but also in spinal, thoracic, abdominal, and orthopedic procedures.…”

Section: Onebeam Ct (Cbct) Is An Advancement In Ct Imagingmentioning

confidence: 99%

Conebeam CT of the Head and Neck, Part 2: Clinical Applications

Miracle¹,

Mukherji²

2009

AJNR Am J Neuroradiol

301

207

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SUMMARY: Conebeam x-ray CT (CBCT) is being increasingly used for point-of-service head and neck and dentomaxillofacial imaging. This technique provides relatively high isotropic spatial resolution of osseous structures with a reduced radiation dose compared with conventional CT scans. In this second installment in a 2-part review, the clinical applications in the dentomaxillofacial and head and neck regions will be explored, with particular emphasis on diagnostic imaging of the sinuses, temporal bone, and craniofacial structures. Several controversies surrounding the emergence of CBCT technology will also be addressed. C onebeam CT (CBCT) is an advancement in CT imagingthat has begun to emerge as a potentially low-dose crosssectional technique for visualizing bony structures in the head and neck. The physical principles, image quality parameters, and technical limitations relevant to CBCT imaging were discussed in Part 1 of this 2-part series. The second part presented here will highlight the evidence related to CBCT applications in head and neck as well as dentomaxillofacial imaging. Controversial aspects of this technology will also be addressed, including limitations in image quality and its often officebased operational model.CBCT was first adapted for potential clinical use in 1982 at the Mayo Clinic Biodynamics Research Laboratory. 1 Initial interest focused primarily on applications in angiography in which soft-tissue resolution could be sacrificed in favor of high temporal and spatial-resolving capabilities. Since that time, several CBCT systems have been developed for use both in the interventional suite and for general applications in CT angiography. 2,3 Exploration of CBCT technologies for use in radiation therapy guidance began in 1992, 4,5 followed by integration of the first CBCT imaging system into the gantry of a linear accelerator in 1999. 6 The first CBCT system became commercially available for dentomaxillofacial imaging in 2001 (NewTom QR DVT 9000; Quantitative Radiology, Verona, Italy). Comparatively low dosing requirements and a relatively compact design have also led to intense interest in surgical planning and intraoperative CBCT applications, particularly in the head and neck but also in spinal, thoracic, abdominal, and orthopedic procedures. [7][8][9][10][11] Diagnostic applications in CT mammography and head and neck imaging are also under evaluation. 12-14 The technical and clinical considerations pertaining to CBCT imaging in many of these applications have been the subjects of several recent reviews. [15][16][17][18][19] The recent review by Dörfler et al 16 of the neurointerventional applications of CBCT is of particular interest to the field of neuroradiology.The discussion below will focus on the diagnostic and treatment-planning applications of CBCT in dentomaxillofacial and head and neck imaging. Commercially available CBCT systems for dentomaxillofacial imaging include the CB MercuRay and CB Throne (Hitachi Medical, Kashiwi-shi, Chiba-ken, Japan), 3D Accuitomo products (J. Mor...

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Section: Onebeam Ct (Cbct) Is An Advancement In Ct Imagingmentioning

confidence: 99%

Conebeam CT of the Head and Neck, Part 2: Clinical Applications

Miracle¹,

Mukherji²

2009

AJNR Am J Neuroradiol

301

207

View full text Add to dashboard Cite

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“…Metrics evaluated in this study include contrast (Contrast), noise (Noise), and contrast-to-noise ratio (CNR) of the tissue-equivalent objects in the reconstructed images. The Contrast of the object can be expressed as (3) Similarly, the Noise in the object can be expressed as (4) where σ obj is the standard deviation of the voxel signal in the object. Therefore, the CNR of the object can be expressed as (5) The statistical uncertainties in the performance metrics were examined using a previously described method for CT imaging.…”

Section: Analysis Methodsmentioning

confidence: 99%

Monte Carlo investigations of megavoltage cone‐beam CT using thick, segmented scintillating detectors for soft tissue visualization

et al. 2007

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Megavoltage cone-beam computed tomography (MY CBCT) is a highly promising technique for providing volumetric patient position information in the radiation treatment room. Such information has the potential to greatly assist in registering the patient to the planned treatment position, helping to ensure accurate delivery of the high energy therapy beam to the tumor volume while sparing the surrounding normal tissues. Presently, CBCT systems using conventional MV active matrix flat-panel imagers (AMFPIs), which are commonly used in portal imaging, require a relatively large amount of dose to create images that are clinically useful. This is due to the fact that the phosphor screen detector employed in conventional MV AMFPIs utilizes only ~2% of the incident radiation (for a 6 MV x-ray spectrum). Fortunately, thick, segmented scintillating detectors can overcome this limitation, and the first prototype imager has demonstrated highly promising performance for projection imaging at low doses. It is therefore of definite interest to examine the potential performance of such thick, segmented scintillating detectors for MV CBCT. In this study, Monte Carlo simulations of radiation energy deposition were used to examine reconstructed images of cylindrical CT contrast phantoms, embedded with tissue-equivalent objects. The phantoms were scanned at 6 MV using segmented detectors having various design parameters (i.e., detector thickness, as well as scintillator and septal wall materials). Due to constraints imposed by the nature of this study, the size of the phantoms was limited to ~6 cm. For such phantoms, the simulation results suggest that a 40 mm thick, segmented CsI detector with low density septal walls can delineate electron density differences of ~2.3% and 1.3% at doses of 1.54 and 3.08 cGy, respectively. In addition, it was found that segmented detectors with greater thickness, higher density scintillator material, or lower density septal walls exhibit higher contrastto-noise performance. Finally, the performance of various segmented detectors obtained at a relatively low dose (1.54 cGy) was compared to that of a phosphor screen similar to that employed in conventional MV AMFPIs. This comparison indicates that, for a phosphor screen to achieve the same contrast-to-noise performance as the segmented detectors, ~18 to 59 times more dose is required, depending on the configuration of the segmented detectors.

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“…One of the major components to keep us away from the goal is setup error which could come from patient positioning, machine uncertainty, revealed internal organ motion, and deformation 1 , 2 , 3 . One of the best solutions is image‐guided radiation therapy (IGRT).…”

Section: Introductionmentioning

confidence: 99%

Long‐term evaluation and cross‐checking of two geometric calibrations of kV and MV imaging systems for Linacs

Chiu

Yan

Foster

et al. 2015

J Applied Clin Med Phys

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Geometric or mechanical accuracy of kV and MV imaging systems of two Varian TrueBeam linacs have been monitored by two geomertirc calibration systems, Varian IsoCal geometric calibration system and home‐developed gQA system. Results of both systems are cross‐checked and the long‐term geometric stabilities of linacs are evaluated. Two geometric calibration methodologies have been used to assess kV and MV imaging systems and their coincidence periodically on two TrueBeam linacs for about one year. Both systems analyze kV or MV projection images of special designed phantoms to retrieve geometric parameters of the imaging systems. The isocenters — laser isocenter and centers of rotations of kV imager and EPID — are then calculated, based on results of multiple projections from different angles. Long‐term calibration results from both systems are compared for cross‐checking. There are 24 sessions of side‐by‐side calibrations performed by both systems on two TrueBeam linacs. All the disagreements of isocenters between two calibrations systems are less than 1 mm with ± 0.1 mm SD. Most of the large disagreements occurred in vertical direction (AP direction), with an averaged disagreement of 0.45 mm. The average disagreements of isocenters are 0.09 mm in other directions. Additional to long‐term calibration monitoring, for the accuracy test, special tests were performed by misaligning QA phantoms on purpose (5 mm away from setup isocenter in AP, SI, and lateral directions) to test the liability performance of both systems with the known deviations. The errors are within 0.5 mm. Both geometric calibration systems, IsoCal and gQA, are capable of detecting geometric deviations of kV and MV imaging systems of linacs. The long‐term evaluation also shows that the deviations of geometric parameters and the geometric accuracies of both linacs are small and very consistent during the one‐year study period.PACS number: 87.56.Fc

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A radiographic and tomographic imaging system integrated into a medical linear accelerator for localization of bone and soft-tissue targets

Cited by 284 publications

References 34 publications

Conebeam CT of the Head and Neck, Part 2: Clinical Applications

Conebeam CT of the Head and Neck, Part 2: Clinical Applications

Monte Carlo investigations of megavoltage cone‐beam CT using thick, segmented scintillating detectors for soft tissue visualization

Long‐term evaluation and cross‐checking of two geometric calibrations of kV and MV imaging systems for Linacs

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