PURPOSE: The goal of this study was to develop a technique for creating a computerized composite maxillofacial-dental model, based on point-based surface best fit algorithm and to test its accuracy. The computerized composite maxillofacial-dental model was made by the three dimensional combination of a 3-dimensional (3D) computed tomography (CT) bone model with digital dental model. MATERIALS AND METHODS: This integration procedure mainly consists of following steps : 1) a reconstruction of a virtual skull and digital dental model from CT and laser scanned dental model ; 2) an incorporation of dental model into virtual maxillofacial-dental model by point-based surface best fit algorithm; 3) an assessment of the accuracy of incorporation. To test this system, CTs and dental models from 3 volunteers with cranio-maxillofacial deformities were obtained. And the registration accuracy was determined by the root mean squared distance between the corresponding reference points in a set of 2 images. RESULTS AND CONCLUSIONS: Fusion error for the maxillofacial 3D CT model with the digital dental model ranged between 0.1 and 0.3 mm with mean of 0.2 mm. The range of errors were similar to those reported elsewhere with the fiducial markers. So this study confirmed the feasibility and accuracy of combining digital dental model and 3D CT maxillofacial model. And this technique seemed to be easier for us that its clinical applicability can good in the field of digital cranio-maxillofacial surgery.
Congenital Abnormalities ; Dental Models ; Fiducial Markers ; Skull

PURPOSE: To develop a method for verifying a treatment setup in stereotactic radiotherapy by matching portal images to DRRs. MATERIALS AND METHODS: Four pairs of orthogonal portal images of one patient immobilized by a thermoplastic mask frame for fractionated stereotactic radiotherapy were compared with DRRs. Portal images are obtained in AP (anterior/posterior) and lateral directions with a target localizer box containing fiducial markers attached to a stereotactic frame. DRRs superimposed over a planned isocenter and fiducial markers are printed out on transparent films. And then, they were overlaid over orthogonal portal images by matching anatomical structures. From three different kind of objects (isocenter, fiducial markers, anatomical structure) on DRRs and portal images, the displacement error between anatomical structure and isocenters (overall setup error), the displacement error between anatomical structure and fiducial markers (immobilization error), and the displacement error between fiducial markers and isocenters (localization error) were measured. RESULTS: Localization errors were 1.5+/-0.3 mm (AP), 0.9+/-0.3 mm (lateral), and immobilization errors were 1.9+/-0.5 mm (AP), 1.9+/-0.4 mm (lateral). In addition, overall setup errors were 1.6+/-0.9 mm (AP), 1.3+/-0.4 mm (lateral). From these orthogonal displacement errors, maximum 3D displacement errors(sqrt{(Delta AP)^2 +(Delta Lat)^2}) were found to be 1.7+/-0.4 mm for localization, 2.6+/-0.6 mm for immobilization, and 2.3+/-0.7 mm for overall treatment setup. CONCLUSION: By comparing orthogonal portal images with DRRs, we find out that it is possible to verify treatment setup directly in stereotactic radiotherapy.
Fiducial Markers ; Humans ; Immobilization ; Masks ; Radiotherapy*

PURPOSE: To assess the distortion of MRI with the Leksell stereotactic radiosurgery system in variable pulse sequence and imaging plane through phantom study, to find most adequate imaging plane and pulse sequence for stereotactic radiosurgery system. MATERIALS AND METHODS: We made the phantoms for MRI and get images in variable conditions and analyzed the image distortion using image analysis program, and statistically using paired student t-test. RESULTS: The transeverse plane images had acceptable error ranges (less than 1.5mm) in all pulse sequence in both the analysis of fiducial marker in stereotactic G-frame and the phantom study. The coronal plane images had unacceptable large errors (more than 1.5mm) in the analysis of fiducial marker in the stereotactic G-frame, but had corrected small errors (less than 1.5mm) in the phantom study. CONCLUSION: We find from the phantom study that the present MR machines are adequate for stereotactic surgery system in frequently used pulse sequences, and imaging planes.
Fiducial Markers ; Humans ; Magnetic Resonance Imaging* ; Radiosurgery*

Technological advances have rapidly expanded the therapeutic potential of endoscopic ultrasound (EUS). Innovations in stent technology; directed adjunctive therapy for pancreatic tumors, including radiofrequency ablation and fiducial marker placement; advanced imaging modalities, including needle-based confocal laser endomicroscopy; and new echoendoscopes, such as the forward-viewing linear echoendoscope, are emerging as safe and effective tools and devices for providing a broad range of treatments and therapies previously not thought possible. In this review, we summarize and discuss the new echoendoscopes, accessories, and stents for interventional EUS and highlight the recent literature on technical and therapeutic efficacy. The therapeutic role and indications for EUS are rapidly evolving well beyond its current limits as new EUS-specific designed tools are designed, and ultimately, should help achieve the goal of improving patient outcomes.
Catheter Ablation ; Endosonography ; Fiducial Markers ; Humans ; Microscopy ; Stents* ; Ultrasonography*

To track moving tumor in real time, CyberKnife system imports a technique of the synchrony respiratory tracking system. The fiducial marker which are detectable in X-ray images were demand in CyberKnife Robotic radiosurgery system. It issued as reference markers to locate and track tumor location during patient alignment and treatment delivery. Fiducial marker implantation is an invasive surgical operation that carries a relatively high risk of pneumothorax. Most recently, it was developed a direct lung tumor registration method that does not require the use of fiducials. The purpose of this study is to measure the accuracy of target applying X-sight lung tracking using the Gafchromic film in dynamic moving thorax phantom. The X-sight Lung Tracking quality assurance motion phantom simulates simple respiratory motion of a lung tumor and provides Gafchromic dosimetry film-based test capability at locations inside the phantom corresponding to a typical lung tumor. The total average error for the X-sight Lung Tracking System with a moving target was 0.85+/-0.22 mm. The results were considered reliable and applicable for lung tumor treatment in CyberKnife radiosurgery system. Clinically, breathing patterns of patients may vary during radiation therapy. Therefore, additional studies with a set real patient data are necessary to evaluate the target accuracy for the X-sight Lung Tracking system.
Fiducial Markers ; Humans ; Lung ; Pneumothorax ; Radiosurgery ; Respiration ; Thorax ; Track and Field

To track moving tumor in real time, CyberKnife system imports a technique of the synchrony respiratory tracking system. The fiducial marker which are detectable in X-ray images were demand in CyberKnife Robotic radiosurgery system. It issued as reference markers to locate and track tumor location during patient alignment and treatment delivery. Fiducial marker implantation is an invasive surgical operation that carries a relatively high risk of pneumothorax. Most recently, it was developed a direct lung tumor registration method that does not require the use of fiducials. The purpose of this study is to measure the accuracy of target applying X-sight lung tracking using the Gafchromic film in dynamic moving thorax phantom. The X-sight Lung Tracking quality assurance motion phantom simulates simple respiratory motion of a lung tumor and provides Gafchromic dosimetry film-based test capability at locations inside the phantom corresponding to a typical lung tumor. The total average error for the X-sight Lung Tracking System with a moving target was 0.85+/-0.22 mm. The results were considered reliable and applicable for lung tumor treatment in CyberKnife radiosurgery system. Clinically, breathing patterns of patients may vary during radiation therapy. Therefore, additional studies with a set real patient data are necessary to evaluate the target accuracy for the X-sight Lung Tracking system.
Fiducial Markers ; Humans ; Lung ; Pneumothorax ; Radiosurgery ; Respiration ; Thorax ; Track and Field

The Viewing Wand is a frameless stereotactic device to provide image-based intraoperative navigation, allowing accurate neurosurgical planning and procedures. The authors applied the frameless stereotactic device called "ISG Viewing Wand" to 30 cases of intracranial lesions and evaluated for its usefulness and limitation. The Viewing Wand was used in 3 cases in conjunction with CT and 27 cases with MRI. The actual error of this system after the registration was judged by the operating surgeon to be less than 2mm in CT or MR image. The useful registrations were possible in 25(83%) out of 30 cases. But it was not useful in 5 cases, because of movement of fiducial markers in 2 cases and head movement after registration in 3 cases. In 25 cases having useful registration, the wand was helpful to localize the lesion for designing the scalp incision and bone flap, as well as the extent of surgical resection of lesions. As a whole, the viewing wand was found to be reliable and accurate. The system is a useful navigational aid that allows a direct approach to intracranial pathology without the drawbacks of application and the limitations of a frame-based stereotactic device.
Fiducial Markers ; Head Movements ; Magnetic Resonance Imaging ; Neuronavigation* ; Pathology ; Scalp

PURPOSE: To assess the effect of a rectal enema on interfraction prostate movement in bone alignment (BA) for prostate radiotherapy (RT), we analyzed the spatial difference in prostates in a bone-matched setup. MATERIALS AND METHODS: We performed BA retrospectively with data from prostate cancer patients who underwent image-guided RT (IGRT). The prostate was identified with implanted fiducial markers. The setup for the IGRT was conducted with the matching of three fiducial markers on RT planning computed tomography images and those on two oblique kV x-ray images. Offline BA was performed at the same position. The coordinates of a virtual prostate in BA and a real prostate were obtained by use of the ExaxTrac/NovalisBody system, and the distance between them was calculated as the spatial difference. Interfraction prostate displacement was drawn from the comparison of the spatial differences. RESULTS: A total of 15 patients with localized prostate cancer treated with curative hypofractionated IGRT were enrolled. A total of 420 fractions were analyzed. The mean of the interfraction prostate displacements after BA was 3.12+/-2.00 mm (range, 0.20-10.53 mm). The directional difference was profound in the anterior-posterior and supero-inferior directions (2.14+/-1.73 mm and 1.97+/-1.44 mm, respectively) compared with the right-left direction (0.26+/-0.22 mm, p<0.05). The required margin around the clinical target volume was 4.97 mm with the formula of van Herk et al. CONCLUSIONS: The interfraction prostate displacement was less frequent when a rectal enema was performed before the procedure. A rectal enema can be used to reduce interfraction prostate displacement and resulting clinical target volume-to-planning target volume margin.
Enema* ; Fiducial Markers ; Humans ; Prostate* ; Prostatic Neoplasms ; Radiotherapy* ; Retrospective Studies

PURPOSE: To assess the usefulness of implanted fiducial markers in the setup of hypofractionated radiotherapy for prostate cancer patients by comparing a fiducial marker matched setup with a pelvic bone match. MATERIALS AND METHODS: Four prostate cancer patients treated with definitive hypofractionated radiotherapy between September 2009 and August 2010 were enrolled in this study. Three gold fiducial markers were implanted into the prostate and through the rectum under ultrasound guidance around a week before radiotherapy. Glycerin enemas were given prior to each radiotherapy planning CT and every radiotherapy session. Hypofractionated radiotherapy was planned for a total dose of 59.5 Gy in daily 3.5 Gy with using the Novalis system. Orthogonal kV X-rays were taken before radiotherapy. Treatment positions were adjusted according to the results from the fusion of the fiducial markers on digitally reconstructed radiographs of a radiotherapy plan with those on orthogonal kV X-rays. When the difference in the coordinates from the fiducial marker fusion was less than 1 mm, the patient position was approved for radiotherapy. A virtual bone matching was carried out at the fiducial marker matched position, and then a setup difference between the fiducial marker matching and bone matching was evaluated. RESULTS: Three patients received a planned 17-fractionated radiotherapy and the rest underwent 16 fractionations. The setup error of the fiducial marker matching was 0.94+/-0.62 mm (range, 0.09 to 3.01 mm; median, 0.81 mm), and the means of the lateral, craniocaudal, and anteroposterior errors were 0.39+/-0.34 mm, 0.46+/-0.34 mm, and 0.57+/-0.59 mm, respectively. The setup error of the pelvic bony matching was 3.15+/-2.03 mm (range, 0.25 to 8.23 mm; median, 2.95 mm), and the error of craniocaudal direction (2.29+/-1.95 mm) was significantly larger than those of anteroposterior (1.73+/-1.31 mm) and lateral directions (0.45+/-0.37 mm), respectively (p<0.05). Incidences of over 3 mm and 5 mm in setup difference among the fractionations were 1.5% and 0% in the fiducial marker matching, respectively, and 49.3% and 17.9% in the pelvic bone matching, respectively. CONCLUSION: The more precise setup of hypofractionated radiotherapy for prostate cancer patients is feasible with the implanted fiducial marker matching compared with the pelvic bony matching. Therefore, a less marginal expansion of planning target volume produces less radiation exposure to adjacent normal tissues, which could ultimately make hypofractionated radiotherapy safer.
Enema ; Fiducial Markers ; Glycerol ; Humans ; Incidence ; Pelvic Bones ; Prostate ; Prostatic Neoplasms ; Rectum

The Cyberknife is an integrated image-guided, frameless radiosurgery system. The physical component includes a compact 6 MV X-band linear accelerator mounted to the mobile arm of a robotic manipulator and a real- time imaging system connected to a remote image registration console. Two orthogonally positioned diagnostic x-ray cameras provide real time images of the patient's internal anatomy during treatment. The images are processed automatically to identify radiographic features, such as skull bone landmarks or implanted fiducials and are then automatically compared with digitally reconstructed image of the patient's planning CT. In this processing, the direction of the radiation beam is continuously re-adjusted to reflect any changes in the patient position. An analysis of the accuracy of the Cyberknife radiosurgery system found that the machine has a clinically relevant accuracy of 1.0 +/- 0.3mm. While clinical results with intracranial lesions are comparable to frame-based radiosurgical technique using gamma-knife or linac, recent experiences demonstrate the potential to broadly expand the scope of radiosurgery to many extracranial sites especially for cancer patients. The major potential benefit of radiosurgical ablation of malignant tumors are relatively short treatment time in an out-patients setting combined with better local control of the tumor with minimal risk of side effects. Cyberknife radiosurgery offers a new and alternative therapeutic modality for the medically inoperable early cancers, previous irradiated sites, and difficult lesions not amenable to open surgery, as a boost therapy with surgery or external radiation therapy or for rapid symptom relief of palliative care patients. While we are encouraged by excellent local control of early clinical experiences of Cyberknife, we also stressed the importance of long term follow-up results.
Arm ; Fiducial Markers ; Humans ; Outpatients ; Palliative Care ; Particle Accelerators ; Radiosurgery ; Radiotherapy, Image-Guided ; Skull