Image Guidance

Clinical evaluation of a "virtual" methodology for providing 6 degrees of freedom (6DOF) patient set-up corrections and comparison to corrections facilitated by a 6DOF robotic couch. A total of 55 weekly in-room image-guidance computed tomographic (CT) scans were acquired using a CT-on-rails for 11 pelvic and head and neck cancer patients treated at our facility. Fusion of the CT-of-the-day to the simulation CT allowed prototype virtual 6DOF correction software to calculate the translations, single couch yaw, and beam-specific gantry and collimator rotations necessary to effectively reproduce the same corrections as a 6DOF robotic couch. These corrections were then used to modify the original treatment plan beam geometry and this modified plan geometry was applied to the CT-of-the-day to evaluate the dosimetric effects of the virtual correction method. This virtual…

Motivation-Image-guided percutaneous (through the skin) needle-based surgery has become part of routine clinical practice in performing procedures such as biopsies, injections and therapeutic implants. A novice physician typically performs needle interventions under the supervision of a senior physician; a slow and inherently subjective training process that lacks objective, quantitative assessment of the surgical skill and performance[S1]. Shortening the learning curve and increasing procedural consistency are important factors in assuring high-quality medical care. Methods-This paper describes a laboratory validation system, called Perk Station, for standardized training and performance measurement under different assistance techniques for needle-based surgical guidance systems. The initial goal of the Perk Station is to assess and compare different techniques: 2D image overlay, biplane laser guide, laser protractor and conventional freehand. The main focus of this manuscript is the planning and guidance software system developed on the 3D Slicer platform, a free, open source software package designed for visualization and analysis of medical image data. Results-The prototype Perk Station has been successfully developed, the associated needle insertion phantoms were built, and the graphical user interface was fully implemented. The system was inaugurated in undergraduate teaching and a wide array of outreach activities. Initial results, experiences, ongoing activities and future plans are reported.

Surgical robotics is a domain where the robot has to interact with human beings in order to treat patients in a very constrained working environment; therefore dependability cannot be ignored. In this paper, we discuss some requirements of this specific domain, and based on the “dependability on design” principle, we propose several directions for improving safety, reliability and man/machine interaction. This discussion will be illustrated by several on-going projects.

Advances in regenerative medicine are rapidly transforming healthcare. A cornerstone of regenerative medicine is the introduction of cells that were grown or manipulated in vitro. Key questions that arise after these cells are re‐introduced are: whether these cells are localized in the appropriate site; whether cells survive; and whether these cells migrate. These questions predominantly relate to the safety of the therapeutic approach (i.e. tumorigenesis), but certain aspects can also influence the efficacy of the therapeutic approach (e.g. site of injection). The European Medicines Agency has indicated that suitable methods for stem cell tracking should be applied where these methods are available. We here discuss the European regulatory framework, as well as the scientific evidence, that should be considered to facilitate the potential clinical implementation of magnetic resonance imaging contrast media to track implanted/injected cells in human studies. Copyright © 2013 John Wil...

We present the proof-of-concept prototype of a prostate biopsy robot to be used inside a conventional high-field MRI scanner. A three degree-offreedom (DOF) mechanical device translates and rotates inside the rectum and enters a needle into the body, and steers the needle to a target point pre-selected by the user. The device is guided by real-time images from the scanner. Networked computers process the medical images and enable the clinician to control the motion of the mechanical device that is operated remotely from outside the imager. The system is also applicable to localized prostate therapy and also demonstrates potential in other intra-cavitary procedures.

We present the concept and prototype of an image-guided robotic system for accurate and consistent placement of percutaneous needles in soft tissue targets under CT-guidance. The system is a promising embodiment of the Surgical CAD/CAM paradigm and as such, easily adaptable to other image guidance modalities, like X-ray fluoroscopy. We also report the first results of pre-clinical experiments on phantoms. Our vision is that by extending human surgeons' ability to plan and carry out surgical interventions more accurately and less invasively, Computer Integrated Surgery (CIS) systems will address a vital need to greatly reduce costs, improve clinical outcomes, and improve the efficiency of health care delivery. Further, the combination of consistent execution, patient and task models, and logging of intraoperative and outcome data made possible by CIS systems will produce the same impact on surgery that has been realized in industrial CAD/CAM systems. Surgical CAD/CAM systems (Figure ) transform preoperative images and other information to the actual patient in the operating room, assist clinicians in developing an optimized interventional plan, register this preoperative data to the actual patient in the operating, and then use a variety of appropriate means, such as robots and image overlay displays, to assist in the accurate execution of the planned interventions. Surgical CAD/CAM systems are analogous to manufacturing CAD/CAM systems. There are three key concepts: "Surgical CAD" is analogous to computer-aided design in manufacturing systems. Preoperatively, medical images, anatomical atlases, and other information are combined to make a model of an individual patient. The computer then assists the surgeon in planning and optimizing an appropriate intervention. "Surgical CAM" is analogous to computer-aided manufacturing, with modifications to fit the specific requirements of surgery. The data from the preoperative planning step (images, models, plan geometry, etc.) is all brought into the operating room. Real time images and other sensor data are used to "register" the preoperative plan to the actual patient, and the model and the plan are updated throughout the procedure. The actual surgical procedure is performed by the surgeon with the assistance of the computer, using appropriate technology for the particular intervention. "Surgical TQM" is analogous to "total quality management" in manufacturing, and reflects the important role that the computer can play in reducing surgical errors and in promoting more consistent and improved outcomes. It is built into the entire process. Percutaneous therapy, which is inserting thin tubular devices (needles, cannulas, electrodes, sensory or tissue ablation probes, etc.) into the body through the skin, fits Computerassisted planning Patient-specific Model Update Model Computer-Assisted Execution Update Plan Computer-Assisted Assessment Preoperative Intraoperative Atlas Postoperative Patient Figure 1: Information flow in surgical CAD/CAM systems naturally within our broader paradigm of Surgical CAD/CAM systems. The basic process involves planning a patient-specific therapy pattern, delivering the therapy through a series of percutaneous access steps, assessing what was actually done, and using this feedback to control the therapy procedure. Our goal is to develop systems that execute this process with robotic assistance under a variety of widely available and deployable image modalities, including ultrasound, x-ray fluoroscopy, and conventional MRI and CT scanners. Initially, we focus on solid organ therapy, in particular the prostate, but will extend and apply these results to other organ systems, such as the brain, liver, bones and spine. As these results become available, they will be combined with image analysis, data fusion, and reconstruction methods developed in parallel research programs. Typical applications of this enhanced system include vertebroplasty, spine nerve block injections, and bone biopsies, incorporating novel techniques for non-straight-line delivery trajectories. Recent advances in medical imaging have propelled minimally invasive image-guided percutaneous biopsy and local therapies into public attention . Intra-operative radiological imaging has become more accurate, faster, affordable, and less toxic to both patients and surgeons. The objective of the presented work was to meet the ultimate

Rationale and Objectives. The purpose of this study was to assess the work-in-progress prototype of an image-guided, robotic system for accurate and consistent placement of transperineal needles into the prostate with intraoperative image guidance inside the gantry of a computed tomographic (CT) scanner. The coach-mounted system consists of a seven-degrees-of-freedom, passive mounting arm; a remote-center-of-motion robot; and a motorized, radiolucent needle-insertion device to deliver 17-18-gauge implant and biopsy needles into the prostate with the transperineal route. The robot is registered to the image space with a stereotactic adapter. The surgeon plans and controls the intervention in the CT scanner room with a desktop computer that receives DICOM images from the CT scanner. The complete system fits in a carry-on suitcase, does not need calibration, and does not utilize vendor-specific features of the CT scanner. Results. In open air, the average accuracy was better than 1 mm at a 5-8-cm depth. In various phantoms, the average orientation error was 1.3°, and the average distance between the needle tip and the target was 2 mm. Results of preliminary experiments indicate that this robotic system may be suitable for transperineal needle placement into the prostate and shows potential in a variety of other percutaneous clinical applications.

Radiofrequency ablation (RFA) represents a convenient, minimally invasive, and cost-effective approach for the treatment of small liver cancers measuring less than 3 cm in diameter. Nonetheless, the existing RFA techniques encounter challenges in precisely controlling the extent of ablation and the risk of overheating, which can lead to damage on the surrounding tissues. The ability to control the ablation area also plays a crucial role in the success of RFA procedures. To address these issues, we introduce a novel method that utilizes tumor boundary temperature monitoring to achieve precise control over the RFA process. Through the utilization of COMSOL Multiphysics simulation software, the proposed method was verified by comprehensive simulation and modeling and its efficacy in achieving regional control was testified. Subsequently, ex vivo experiments were conducted employing a custom-designed cooling RFA instrument. The experimental results demonstrated that the RFA controlled by boundary temperature yielded an ablation area with a diameter approaching 30 mm. In comparison to the standard spherical solidification zone (characterized by both the ellipticity and regularity indices of 1), the cooling RFA discoloration zone, under boundary temperature control, exhibited a maximum deviation of 7% in the ellipticity index and 17% in the regularity index. The average ellipticity index was determined to be 0.96, while the average regularity index was 0.86. Collectively, these findings underscore the capability of the proposed temperature-controlled cooling RFA method to attain precise control over the ablation area, contributing to comprehensive ablation of tumor tissue within the target region.

Low-field magnetic resonance imaging (MRI) has recently been integrated with radiation therapy systems to provide image guidance for daily cancer radiation treatments. The main benefit of the low-field strength is minimal electron return effects. The main disadvantage of low-field strength is increased image noise compared to diagnostic MRIs conducted at 1.5 T or higher. The increased image noise affects both the discernibility of soft tissues and the accuracy of further image processing tasks for both clinical and research applications, such as tumor tracking, feature analysis, image segmentation, and image registration. An innovative method, adaptive anatomical preservation optimal denoising (AAPOD), was developed for optimal image denoising, i.e., to maximally reduce noise while preserving the tissue boundaries. AAPOD employs a series of adaptive nonlocal mean (ANLM) denoising trials with increasing denoising filter strength (i.e., the block similarity filtering parameter in the ANLM algorithm), and then detects the tissue boundary losses on the differences of sequentially denoised images using a zero-crossing edge detection method. The optimal denoising filter strength per voxel is determined by identifying the denoising filter strength value at which boundary losses start to appear around the voxel. The final denoising result is generated by applying the ANLM denoising method with the optimal per-voxel denoising filter strengths. The experimental results demonstrated that AAPOD was capable of reducing noise adaptively and optimally while avoiding tissue boundary losses. AAPOD is useful for improving the quality of MRIs with low-contrast-to-noise ratios and could be applied to other medical imaging modalities, e.g., computed tomography.

Purpose-In this study, protein-shell microspheres filled with a suspension of iron oxide nanoparticles in oil are demonstrated as multimodal contrast agents in magnetic resonance imaging (MRI), magnetomotive optical coherence tomography (MM-OCT), and ultrasound imaging. The development, characterization, and use of multifunctional multimodal microspheres are described for targeted contrast and therapeutic applications. Procedures-A preclinical rat model was used to demonstrate the feasibility of the multimodal multifunctional microspheres as contrast agents in ultrasound, MM-OCT and MRI. Microspheres were functionalized with the RGD peptide ligand, which is targeted to α v β 3 integrin receptors that are over-expressed in tumors and atherosclerotic lesions. Results-These microspheres, which contain iron oxide nanoparticles in their cores, can be modulated externally using a magnetic field to create dynamic contrast in MM-OCT. With the presence of iron oxide nanoparticles, these agents also show significant negative T2 contrast in MRI. Using ultrasound B-mode imaging at a frequency of 30 MHz, a marked enhancement of scatter intensity from in vivo rat mammary tumor tissue was observed for these targeted protein microspheres. Conclusions-Preliminary results demonstrate multimodal contrast-enhanced imaging of these functionalized microsphere agents with MRI, MM-OCT, ultrasound imaging, and fluorescence

Aim: To evaluate the safety and efficacy of uncooled TATO microwave ablation (MWA) for primary and metastatic liver cancer. Materials & methods: This was a retrospective study on percutaneous liver ablations performed with TATO MWA. Twenty-five ablations were performed; 11 (44%) were performed for hepatocellular carcinoma, 14 (56%) for colorectal carcinoma, gastric and pancreatic metastases. Results: Adverse events were reported only in one (4%) ablation: an abscess that was observed in the ablated area and was resolved with a percutaneous drainage and antibiotic therapy. Local tumor control rate was 92% at the 3-month follow-up. Conclusion: TATO MWA was safe and effective with high reproducibility in treating primary and secondary liver cancer with satisfactory technical and clinical outcomes.

Background: Radiosurgery is defined as the use of high-dose ionizing radiation for precise and total destruction of a chosen target, avoiding concomitant or delayed harm to adjacent tissues. The three types of radiations include gamma rays (GammaKnife) by Cobalt-60, X8 rays using linear accelerator (LINAC) system, and charged-particles generated from synchocyclotron. Recommendations: Based on current evidence, radiosurgery has proven benefits as the treatment of certain brain metastases, vestibular schwannomas, meningiomas, and some skull base tumors. Conclusion: This review describes the current recommendations for use of radiosurgery for intracranial pathologies. Radiosurgery is a relatively newer modality in the developing country of Pakistan. Much work is needed to increase awareness and promote its use as and when indicated.

Purpose Currently, intraoperative ultrasound in brain tumor surgery is a rapidly propagating option in imaging technology. We examined the accuracy and resolution limits of different ultrasound probes and the influence of 3D-reconstruction in a phantom and compared these results to MRI in an intraoperative setting (iMRI). Methods An agarose gel phantom with predefined gel targets was examined with iMRI, a sector (SUS) and a linear (LUS) array probe with two-dimensional images. Additionally, 3D-reconstructed sweeps in perpendicular directions were made of every target with both probes, resulting in 392 measurements. Statistical calculations were performed, and comparative boxplots were generated. Results Every measurement of iMRI and LUS was more precise than SUS, while there was no apparent difference in height of iMRI and 3D-reconstructed LUS. Measurements with 3D-reconstructed LUS were always more accurate than in 2D-LUS, while 3D-reconstruction of SUS showed nearly no differences to 2D-SUS in some measurements. We found correlations of 3D-reconstructed SUS and LUS length and width measurements with 2D results in the same image orientation. Conclusions LUS provides an accuracy and resolution comparable to iMRI, while SUS is less exact than LUS and iMRI. 3D-reconstruction showed the potential to distinctly improve accuracy and resolution of ultrasound images, although there is a strong correlation with the sweep direction during data acquisition.

Although the use of image guidance surgery (IGS) is standard practice in developed countries, it has not been in use in Indian Otolaryngology ever since its clinical inception in 1994. Some clinically interesting applications, relevant indications, practical tips and results in the Indian context are presented. Usage technique and data presentation. Indications based on AAO-HNS 2002 guidelines seem valid, and though the accuracy parameters remain still guarded, in line with the best technology available, based on the evidences of scattered reports and expert opinions, the use of navigation can be recommended as state of the art. IGS provides reliable information to a sinus surgeon in difficult circumstances. Its adaptation fortunately does not require a significant learning curve as it does not change the methodology of the surgical procedure. It can be an excellent teaching tool, but its use does not replace proper surgical training.

Objective. The purpose of this study was to assess the correlation between skin-to-epidural space depth, as measured on cervical magnetic resonance imaging (MRI), and actual needle depth, as measured by Tuohy needle markings during cervical epidural steroid injections. Methods. We conducted a retrospective review of cervical MRI images to determine estimated depth from skin to epidural space. Of the 121 reviewed patients who underwent cervical epidural steroid injections, 81 met inclusion criteria and were retained for data analysis. Results. At the C6-C7 level, the estimated needle depth according to MRI images was 6.036 1.15 cm (mean 6 SD) and the actual needle depth was 5.62 6 0.77 cm. At the C7-T1 level, the estimated needle depth based on MRI images was 5.90 6 1.05 cm and the actual needle depth was 5.73 6 0.98 cm. At both C6-C7 and C7-T1, MRI depth (P < 0.009, P < 0.001) and body mass index (P < 0.001, P < 0.002) were significantly associated with actual depth. Conclusions. Estimates of needle depth made with MRI were consistently slightly deeper than the actual loss-of-resistance needle depth, indicating that the provider should employ caution when using MRI predictive depths. Information garnered from preprocedure MRIs can be used to improve the safety of cervical epidural steroid injection procedures.

Objective. The purpose of this study was to assess the correlation between skin-to-epidural space depth, as measured on cervical magnetic resonance imaging (MRI), and actual needle depth, as measured by Tuohy needle markings during cervical epidural steroid injections. Methods. We conducted a retrospective review of cervical MRI images to determine estimated depth from skin to epidural space. Of the 121 reviewed patients who underwent cervical epidural steroid injections, 81 met inclusion criteria and were retained for data analysis. Results. At the C6-C7 level, the estimated needle depth according to MRI images was 6.036 1.15 cm (mean 6 SD) and the actual needle depth was 5.62 6 0.77 cm. At the C7-T1 level, the estimated needle depth based on MRI images was 5.90 6 1.05 cm and the actual needle depth was 5.73 6 0.98 cm. At both C6-C7 and C7-T1, MRI depth (P < 0.009, P < 0.001) and body mass index (P < 0.001, P < 0.002) were significantly associated with actual depth. Conclusions. Estimates of needle depth made with MRI were consistently slightly deeper than the actual loss-of-resistance needle depth, indicating that the provider should employ caution when using MRI predictive depths. Information garnered from preprocedure MRIs can be used to improve the safety of cervical epidural steroid injection procedures.

An epidural steroid injection may help alleviate radicular pain felt in either your arm or leg resulting from pressure and irritation on one of the nerves. Once positioned appropriately by your doctor, a fluoroscope (X-ray guided machine) assists in identifying the specific area to be injected. The area is then cleansed and the skin is numbed. The needle is inserted under X-ray guidance into the epidural space (the small space surrounding the nerves inside the spinal canal). A special Xray dye will be used to verify that the needle has been correctly placed and that the medication will be delivered to the appropriate site. A long-acting anti-inflammatory steroid and local anesthetic are usually administered and the needle is removed.

Purpose: To assess the optimal planning target volume (PTV) margins for stereotactic body radiotherapy (SBRT) of prostate cancer based on inter-and intra-fractional prostate motion determined from daily image guidance. Methods and Materials: Two hundred and five patients who were enrolled on two prospective studies of SBRT (8 Gy × 5 fractions) for localized prostate cancer treated at a single institution between 2012 and 2017 had complete inter-and intra-fractional shift data available. All patients had scheduled kilovoltage planar imaging during SBRT with rigid registration to intraprostatic fiducials prior to each of four half-arcs delivered per fraction, as well as cone beam CT verification of anatomy prior to each fraction. Inter-and intra-fractional shift data were obtained to estimate the required PTV margins based on the classic van Herk formula. Inter-and intra-fractional motion were compared between patients with and without severe toxicities using the independent two-sample Wilcoxon test. The margins required to account for inter-fractional motion were estimated to be 0.99, 1.52, and 1.45 cm in lateral (LR), longitudinal (SI), and vertical (AP) directions, respectively. The margins required to account for intra-fractional motion were estimated to be 0.19, 0.27, and 0.31 cm in LR, SI and AP directions, respectively. Large intra-fractional shifts were mostly observed in the SI and AP directions, with 2.0 and 5.4% of patients experiencing average intra-fractional motion >3 mm in the SI and AP directions, respectively, compared with none experiencing mean shifts >3 mm in the LR direction. Six patients experienced grade 3 gastrointestinal or genitourinary toxicity. There were no significant differences in mean inter-or intra-fractional motion in any of the cardinal directions compared to patients without severe toxicity (inter-fractional p = 0.46-0.99, intra-fractional p = 0.10-0.84). The inter-and intra-fractional margins estimated from this study are in line with prior reported values. Intra-fractional prostate motion was generally small with larger margins required for the SI and AP directions, notably just slightly exceeding the commonly used 3 mm posterior PTV margin even with realignment between half-arcs. Development of severe toxicity was not significantly associated with the degree of inter-or intra-fractional motion.

The aim of the current study is to present our experience in lumbar spine interventional procedures performed with a newly developed multimodal echo-navigator (EcoNav) and to evaluate short-term clinical outcomes of a series of patients affected by facet joint disease (FJD) treated with steroid and anaesthetic injection under fusion-imaging guidance, compared to a cohort of patients that received the same treatment under computed tomography (CT) guidance. Sixty-five consecutive patients (34 females; mean age 68.3 ± 12.8 years) with a clinical diagnosis of non-radicular low back pain lasting for more than 6-weeks and magnetic resonance (MR) or CT confirmed FJD were enrolled for image-guided FJI. Twenty-eight patients underwent FJI with fusion-guided technique, while CT-guided procedures were performed in the other cases. Clinical and procedural data were recorded and compared at a mean follow-up of 6.1 ± 2.0 months. A significant improvement in clinical parameters was observed for bo...

Objectives: Although large lesions of the limbs can easily be biopsied without image guidance, lesions in the spine, paraspinal area and pelvis are difficult to target, and benefit from CT guidance to improve the accuracy of targeting the lesion for biopsy purposes. A prospective study of CT-guided core needle biopsies for deep-seated musculoskeletal lesions was conducted at a referral cancer institute over a 4-year period with the aim of assessing the safety and efficacy of the procedure. Patients & methods: From January 2000 to December 2003, 136 consecutive CT-guided biopsy sessions were undertaken for musculoskeletal lesions in 128 patients comprising 73 males and 55 females. The following data

Purpose-To assess the accuracy of kV cone-beam CT (CBCT) based setup corrections as compared to orthogonal MV portal image-based corrections for patients undergoing external-beam radiotherapy of the prostate. Method and Materials-Daily cone-beam CT volumetric images were acquired after setup for patients with three intra-prostatic fiducial markers. The estimated couch shifts were compared retrospectively to patient adjustments based on two orthogonal MV portal images (the current clinical standard of care in our institution). The CBCT soft-tissue based shifts were also estimated by digitally removing the gold markers in each projection to suppress the artifacts in the reconstructed volumes. A total of 256 volumetric images for 15 patients were analyzed. Results-The Pearson coefficient of correlation for the patient position shifts using fiducial markers in MV vs kV was (R 2 = 0.95, 0.84, 0.81) in the L/R, A/P and S/I directions respectively. The correlation using soft-tissue matching was ((R 2 = 0.90, 0.49, 0.51) in the L/R, A/P and S/I directions. A Bland-Altman analysis showed no significant trends in the data. The percentage of shifts within a +/-3mm tolerance (the clinical action level) was (99.7, 95.5, 91.3) for fiducial marker matching and (99.5, 70.3, 78.4) for soft-tissue matching. CT is an accurate and precise tool for image-guidance. It provides an equivalent means of patient setup correction for prostate patients with implanted gold fiducial markers. Use of the additional information provided by the visualization of soft-tissue structures is an active area of research.

Image guidance is a technique that often uses virtual reality to provide accurate localization and real-time surgical navigation. Combining image guidance with a biosensor based on Raman spectroscopy, a powerful laser-based analysis technique, would provide a surgeon both a diagnosis of tissue being analyzed (e.g. cancer) and localization information displayed within an imaging modality of choice. A virtual reality-based presentation of this type of mutual and registered information could lead to faster diagnoses and enable more accurate tissue resections. For our system, a portable Raman probe was attached to a passively articulated mechanical arm and used to scan and classify objects within a phantom skull. We discuss the implementation of the integrated system, its accuracy, its visualization techniques, and the future steps for its development and eventual application.

To investigate the impact of daily image-guided radiation therapy (IGRT) technique on clinical outcomes in patients with inoperable non-small cell lung cancer (NSCLC) treated with definitive chemoradiation therapy (CRT). We compared patients with inoperable NSCLC receiving daily cone beam computed tomography (CBCT) after an initial 4-dimensional computed tomography (4DCT) simulation (N = 76) to those receiving daily 2-dimensional (2D) orthogonal kilovoltage (kV) imaging (N = 48). The primary endpoint was time to Grade ≥ 2 radiation pneumonitis (RP2), estimated with the cumulative incidence method, compared with Gray's test, and modeled with the Fine-Gray method. Results: Median follow-up was 40.6 months (range, 5.9-58.1 months) for the CBCT group and 75.8 months (range, 9.9-107.8 months) for the orthogonal kV group. 4DCT simulation was used in 100% (N = 76) of the CBCT group and 56% (N = 27) of the orthogonal kV group (P < 0.0001). The 1-year cumulative incidence of RP2 was lower in the CBCT group than in the orthogonal kV group (24% vs 44%, P = 0.020). On multivariate analysis, daily imaging with CBCT after an initial 4DCT simulation was associated with a decreased risk of RP2 (adjusted HR 0.43, 95% CI 0.22-0.82, P = 0.011), a finding which persisted among only patients who received 4DCT simulation (adjusted HR 0.48, 95% CI 0.23-0.98, P = 0.045). There was no difference in locoregional progression, distant metastasis, any progression, or OS between groups.

The ability to determine the accuracy of the final prostate position within a determined action level threshold for image-guided proton therapy is unclear. Materials and Methods: Three thousand one hundred ten images for 20 consecutive patients treated in 1 of our 3 proton prostate protocols from February to May of 2007 were analyzed. Daily kV images and patient repositioning were performed employing an action-level threshold (ALT) of Ն2.5 mm for each beam. Isocentric orthogonal x-rays were obtained, and prostate position was defined via 3 gold markers for each patient in the 3 axes. Results: To achieve and confirm our action level threshold, an average of 2 x-rays sets (median 2; range, 0 -4) was taken daily for each patient. Based on our ALT, we made no corrections in 8.7% (range, 0%-54%), 1 correction in 82% (41%-98%), and 2 to 3 corrections in 9% (0 -27%). No patient needed 4 or more corrections. All patients were treated with a confirmed error of Ͻ2.5 mm for every beam delivered. After all corrections, the mean and standard deviations were: anterior-posterior (z): 0.003 Ϯ 0.094 cm; superiorinferior (y): 0.028 Ϯ 0.073 cm; and right-left (x) Ϫ0.013 Ϯ 0.08 cm. Conclusion: It is feasible to limit all final prostate positions to less than 2.5 mm employing an action level image-guided radiation therapy (IGRT) process. The residual errors after corrections were very small.

Awake Craniotomy with endoscopic support, guided by intraoperative
ultrasound, Imeka Neuronavigator and MRI for excision of low-grade Astrocytoma
in Sharab Hospital. Case Report.
Fontes C1; Sama Y2; Sulayman S 3; BaldehS 4; Ceesay A5; Copello DL6
1. Carlos Fontes. Licensed Nurse in Anesthesiology and Resuscitation. Master's
Degree in Emergencies, Assistant Professor University of Medical Sciences of
Camaguey. Cuba. Anesthesiology Service, Sharab Hospital. Republic of The
Gambia.
2. Sama Yamundaw. Nurse Anesthesiologist Nurse. Anesthesiology Service at
Sharab Hospital. Republic of The Gambia
3. Sulayman Sima. Sharab Hospital Surgery Service. Republic of The Gambia.
4. Sanna Baldeh. Scrubs Nurse. Sharab Hospital Surgery Service. Republic of The
Gambia.
5. 5 Abdoulie Ceesay. Scrubs Nurse. Sharab Hospital Surgery Service. Republic of
The Gambia
6. Dr.Damian Lastra Copello. Consultant Neurosurgeon.MD. Emergency and
Critical Care Fellowship. Neuro-Oncology and Spine Surgeon, Lecturer,
Researcher, Santiago de Cuba Medical Sciences University, Havana University,
Cuba. Neurosurgery Service Sharab Hospital. The Gambia.
ORCID: 0000-0002-9393-1933
Abstract
Low-grade astrocytomas are considered low-grade gliomas. Low-grade gliomas are
brain tumors that grow slowly and require specialized care.
They are a group of tumors that include: fibrillary astrocytoma, protoplasmic
astrocytoma and gemistocytic astrocytoma. They differ from their counterpart high-
grade astrocytomas, because they have a better prognosis and longer survival,
although each of them is a different disease with a different course and prognosis.As a
group, they represent 26.6% of all tumors derived from glial cells in the brain.Separated
by age, they represent approximately 15% of intracranial tumors in adults and 25% in
children. (1 -8)
The age of presentation of these tumors in adults is around the 4th decade of life. The
frontal lobe is the most frequent location, followed by the temporal and parietal lobes.
Currently, technology has increased the safety of surgical procedures, with the arrival of
techniques such as neuronavigation, stereotaxy, transoperative brain mapping,
transoperative ultrasound or ultrasonic aspirator; all of them in contemporary times must
be used with reasoning for the greater benefit of the patient.
A craniotomy is a complex neurological procedure that involves opening the skull,
performing the necessary operation, and closing the skull, securing the bone in its
original position. (4 -10)
Awake craniotomy is mainly used for mapping and resection of lesions in vitally
important brain areas where imaging is not sufficiently sensitive. These are most
commonly speech and motor areas. In all sedation-anesthesia techniques, the
patients are awake and able to speak and/or move during the mapping phase.
It is a technique used to improve perioperative outcomes, achieving a faster
recovery of the patient with a reduction in the percentage of postoperative
complications. (6 -10) We present the case of a 70-year-old male patient admitted
to our center presenting a picture of progressive consciousness deterioration,
with central facial paralysis, mixed aphasia, disorientation and proportional left
hemiplegia.
It was decided to perform a minimal frontal awake craniotomy guided by
intraoperative ultrasound, endoscopic support and Imeka- Neuronavigator,
achieving maximum safe resection of Intracranial lesion with Satisfactory result.
Discussion:
Historically, craniotomies have been associated with significant morbidity and
mortality. In modern practice, large craniotomies have been replaced by smaller
mini-craniotomies, but even these, although in smaller percentages, continue to
be associated with significant postoperative morbidity and mortality. Awake
limited minimal craniotomy is a modern, well-documented technique with
excellent results that considerably reduces the risk of perioperative
complications. Thanks to brain mapping and advanced neuronavigation systems
and anesthesia techniques, it constitutes a safe therapeutic option in the 21st
century for the treatment of our patients in Neuro-Oncology Specialty. ( 5-10)
Conclusions:
• Awake craniotomy is a modern and safer technique than conventional
approaches for treating intra-axial lesions of gliomatous origin. Along with MRI-
and transcranial ultrasound-guided, endoport technique and neuro-navigation, it
allows for obtaining a biopsy and performing safe excision, reducing intracranial
pressure and improving patients' neurological symptoms.
• Reporting of a greater number of diagnosed and operated cases in The Gambia
is required to establish, with scientific evidence, the role of this technique as main
surgical treatment for the excision of low-grade gliomas in the country.
*Corresponding Author: Damian Lastra Copello. ORCID: 0000-0002-9393-
1933.damianlastra2@gmail.com
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 There is no conflict of interest
 No external funding required

Intraoperative MRI has recently entered the operating room as a new imaging modality. Customized visualization systems might furrher facilitate the use of this imaging technology. A visualization system for use in the interventional MTU has been developed, providing a virtual environment for surgical navigation using real-time images and for controlling the scanner. The visualization system has customized features for certain clinical applications. A tl-aining and testing hcility has also been established. The introduction of the visualization system in the interventional MRI overcame several ambiguities and inconsistencies that were previously present, and resulted in a more transparent man-machine intehce approach. A pilot study using the sohare to place cryoprobes in an animal liver showed promising results. Augmentation of real-time MR images with 3D rendering and customized navigation features opens new possibilities in intraoperative MRI. The described system can also be extended to other intraoperative imaging modalities. Comp Aid Surg 7:187-196 (2002). QZOOZ Wiey-Liss, hc

Synchrotron microbeam radiation therapy is a promising pre-clinical radiation treatment modality; however, it comes with many technical challenges. This study describes the image guidance protocol used for Australia’s first long-term pre-clinical MRT treatment of rats bearing 9L gliosarcoma tumours. The protocol utilises existing infrastructure available at the Australian Synchrotron and the adjoining Monash Biomedical Imaging facility. The protocol is designed and optimised to treat small animals utilising high-resolution clinical CT for patient specific tumour identification, coupled with conventional radiography, using the recently developed SyncMRT program for image guidance. Dosimetry performed in small animal phantoms shows patient dose is comparable to standard clinical doses, with a CT associated dose of less than 1.39cGy and a planar radiograh dose of less than 0.03cGy. Experimental validation of alignment accuracy with radiographic film demonstrates end to end accuracy of ...

This paper aims to describe a case of an immunocompetent 60-year-old patient presenting a subarachnoid hemorrhage in the absence of aneurysmal disease. Initial evaluation pointed to vasculitis of the central nervous system secondary to meningeal infection. After initial treatment, a cerebrospinal fluid leak was identified, with no antecedent of trauma, elucidating the origin of infection. Primary cerebrospinal fluid rhinorrhea has nonspecific symptomatology, defying diagnosis, and potentially serious complications. It represents an unusual predisposing factor for meningeal infection and secondary vasculitis. This case report exemplifies a feared complication of spontaneous cerebrospinal fluid leakage.

We present the proof-of-concept prototype of a prostate biopsy robot to be used inside a conventional high-field MRI scanner. A three degree-offreedom (DOF) mechanical device translates and rotates inside the rectum and enters a needle into the body, and steers the needle to a target point pre-selected by the user. The device is guided by real-time images from the scanner. Networked computers process the medical images and enable the clinician to control the motion of the mechanical device that is operated remotely from outside the imager. The system is also applicable to localized prostate therapy and also demonstrates potential in other intra-cavitary procedures.

Background-Cardiac perforation during atrial septal puncture (ASP) might be avoided by improved image guidance. X-ray fluoroscopy (XRF), which guides ASP, visualizes tissue poorly and does not convey depth information. Ultrasound is limited by device shadows and constrained imaging windows. Alternatively, real-time MRI (rtMRI) provides excellent tissue contrast in any orientation and may enable ASP and balloon atrial septostomy (BAS) in swine. Materials and Methods-Custom MRI catheters incorporated "active" (receiver antenna) and "passive" (iron or gadolinium) elements. Wholly rtMRI-guided transfemoral ASP and BAS were performed in 10 swine in a 1.5T interventional suite. Hemodynamic results were measured with catheters and velocity encoded MRI. Results-Successful ASP was performed in all 10 animals. Necropsy confirmed septostomy confined within the fossa ovalis in all. BAS was successful in 9/10 animals. Antenna failure in a reused needle led to inadvertent vena cava tear prior to BAS in one animal. ASP in the same animal was easily performed using a new needle. rtMRI illustrated clear device-tissue-lumen relationships in multiple orientations, and facilitated simple ASP and BAS. The mean procedure time was 19 ± 10 minutes. Septostomy achieved a mean left to right shunt ratio of 1.3:1 in these healthy animals. rtMRI permits rapid transcatheter ASP and BAS in swine. Further technical development may enable novel applications.

Purpose In the surgical treatment for lower-leg intraarticular fractures, the fragments have to be positioned and aligned to reconstruct the fractured bone as precisely as possible, to allow the joint to function correctly again. Standard procedures use 2D radiographs to estimate the desired reduction position of bone fragments. However, optimal correction in a 3D space requires 3D imaging. This paper introduces a new navigation system that uses pre-operative planning based on 3D CT data and intra-operative 3D guidance to virtually reduce lower-limb intra-articular fractures. Physical reduction in the fractures is then performed by our robotic system based on the virtual reduction. Methods 3D models of bone fragments are segmented from CT scan. Fragments are pre-operatively visualized on the screen and virtually manipulated by the surgeon through a dedicated GUI to achieve the virtual reduction in the fracture. Intra-operatively, the actual position of the bone fragments is provided by an optical tracker enabling real-time 3D guidance. The motion commands for the robot connected to the bone fragment are generated, and the fracture physically reduced based on the surgeon's virtual reduction. To test the system, four femur models were fractured to obtain four different distal femur fracture types. Each one of them was

Pre-curved needles are used in a variety of medical applications for both passive and active control of instrument position. In one application, the deployment of a pre-curved stylet from a concentric outer cannula can be used to achieve lateral positioning of the distal tip of the stylet. This paper outlines how the material and geometry of the stylet can be chosen to ensure that it will not yield and thus repeatably return to its pre-curved shape when deployed from a cannula. Using this methodlogy we calculate the maximum strain for a range of stylet geometries and show that nitinol is required for the stylet material in order for then to not plastically deform. Then, sixteen stylets of varying diameter (0.508, 0.635, 0.838 and 0.990 mm) and radius of curvature (10, 20, 30 and 40 mm) were manufactured. Experiments were performed with four different diameter cannulas (20, 18, 16 and 14 gauge) to measure the forces required to deploy the stylets from and retract them back inside the cannulas. Retraction forces were measured between 0.3 and 13.9N, and deployment forces were measured between 0.2 and 7.0N. For a given cannula it was found that force increases as stylet diameter increases and bend radius decreases.

Background Commercially available systems for computer-assisted pedicle screw placement are prohibitively expensive, even in advanced countries. The advantage of the great accuracy of computer-assisted systems for pedicle screw insertion makes them highly desirable and essential for current spinal surgeries. We have tried to develop a new software for pedicle screw placement, based on paired point matching. The newly developed software is much less expensive and is an excellent educational tool. Its accuracy has been established by a cadaveric study, described in this paper. The cadaveric study supports the view that computer-assisted pedicle screw fixation using the newly developed software is superior to the conventional fluoroscopic method, especially with regard to the thoracic spine, where a higher degree of accuracy is needed. Further clinical studies are planned and the software needs further refinement for complex clinical situations.

Bilgisayar teknolojisindeki gelișmelere paralel olarak görüntüleme yöntemlerinde de gelișmeler olmuș, tüm bunlar radyoterapi planlama sistemlerinde daha kompleks planlamalar yapmaya olanak sağlamıștır. Bu gelișmeler üç-boyutlu konformal radyoterapi, yoğunluk ayarlı radyoterapi, görüntü kılavuzluğunda radyoterapi ve stereotaktik radyoterapi olarak özetlenebilir. Tüm bu yeni modaliteler ile tümöre en uygun șekilde radyasyon verilirken, normal sağlıklı doku da mümkün olduğunca korunabilmektedir. Bu derlemede, radyoterapi alanındaki yeniliklerin, prensipleri, teknolojik gereklilikleri ve klinik uygulamaları ile tümör ve normal dokudaki etkileri özetlenmektedir.

Precise patient positioning is critical due to the large fractional doses and small treatment margins employed for thoracic stereotactic body radiation therapy (SBRT). The goals of this study were to evaluate the following: (1) the accuracy of kilovoltage x-ray (kV x-ray) matching to bony anatomy for pretreatment positioning; (2) the magnitude of intrafraction tumor motion; and (3) whether treatment or patient characteristics correlate with intrafraction motion. Methods and Materials: Eighty-seven patients with lung cancer were treated with SBRT. Patients were positioned with orthogonal kV x-rays matched to bony anatomy followed by cone-beam computed tomography (CBCT), with matching of the CBCT-visualized tumor to the internal gross target volume obtained from a 4-dimensional CT simulation data set. Patients underwent a posttreatment CBCT to assess the magnitude of intrafraction motion. Results: The mean CBCT-based shifts after initial patient positioning using kV x-rays were 2.2 mm in the vertical axis, 1.8 mm in the longitudinal axis, and 1.6 mm in the lateral axis (n = 335). The percentage of shifts greater than 3 mm and 5 mm represented 39% and 17%, respectively, of all fractions delivered. The mean CBCT-based shifts after treatment were 1.6 mm vertically, 1.5 mm longitudinally, and 1.1 mm laterally (n = 343). Twenty-seven percent and 10% of shifts were greater than 3 mm and 5 mm, respectively. Univariate and multivariable analysis demonstrated a significant association between intrafraction motion with weight and pulmonary function. Conclusions: Kilovoltage x-ray matching to bony anatomy is inadequate for accurate positioning when a conventional 3-5 mm margin is employed prior to lung SBRT. Given the treatment

Aims and background. The present study evaluated toxicity, local control, and survival in patients with relapsed high-grade glioma after surgery and external beam radiation therapy and treated with re-operation and GliaSite brachytherapy. Methods. Between 2006 and 2008, 15 patients with recurrent high-grade glioma underwent re-operation and GliaSite brachytherapy. Ten patients were males and 5 females. Median age was 40 years (range, 20-71). Karnofsky performance status was ≥70. All patients but one received GliaSite irradiation of the surgical cavity wall at the dose of 4500 cGy at a depth of 1 cm. No severe acute side effects were observed during GliaSite brachytherapy. Pathologically documented, symptomatic late radiation necrosis was observed in 3 patients (20%); 2 subsequently died of further complications. Two patients were alive at a median follow-up 13 months (range, 1-30). Median overall survival after GliaSite brachytherapy was 13 months. Patients with recurrent high-grade glioma can be treated with additional surgery and GliaSite brachytherapy, delivering 4500 cGy at 1 cm depth without significant acute side effects but with a significant rate (20%) of late radiation necrosis, resulting in 13% of treatment-related deaths. Compared with the literature, survival results in our study appear to be satisfactory, but they may be related to patient selection criteria. Re-intervention followed by GliaSite brachytherapy should not be offered as a standard treatment for recurrent high-grade glioma, because of the high rate of late complications, treatment-related deaths, and high treatment costs.

Demands for mechanical accuracy of medical linear accelerators are increased due to the stereotactic and modulated rotational treatments. Mechanical inaccuracies affect the size and shape of the mechanical and radiation isocenters. In practice, the mechanical isocenter is defined by the intersection of rotational axes. However, there are no simple tools to check the properties of the mechanical isocenter in 3D. We introduce a new photography-based method for quick and sub-millimeter accurate determination of the mechanical isocenter. The method is based on image-processing algorithm and modified front pointer. The results demonstrate the quick measurement and visualization of the mechanical isocenter.

Demands for mechanical accuracy of medical linear accelerators are increased due to the stereotactic and modulated rotational treatments. Mechanical inaccuracies affect the size and shape of the mechanical and radiation isocenters. In practice, the mechanical isocenter is defined by the intersection of rotational axes. However, there are no simple tools to check the properties of the mechanical isocenter in 3D. We introduce a new photography-based method for quick and sub-millimeter accurate determination of the mechanical isocenter. The method is based on image-processing algorithm and modified front pointer. The results demonstrate the quick measurement and visualization of the mechanical isocenter.

The advent of advanced technologies has brought unprecedented precision and efficacy to neurosurgical procedures for brain tumor resection. Despite the remarkable progress, disparities in tech- nology access across different nations persist, creating significant challenges in providing equitable neurosurgical care. The purpose of the following work was to comprehensively analyze the existing disparities in access to innovative neurosurgical technologies and the impact of such disparities on patient outcomes and research. We seek to shed light on the extent of the problem, the underlying causes, and propose strategies for mitigating these disparities.

Proton computed tomography has been suggested as a means for maximizing the potential benefits of proton radiation therapy. By measuring individual proton energy losses after traversing an object and predicting paths of maximum likelihood through the image space, relative stopping power maps can be generated for treatment planning and image guidance. However, the processes of proton interaction with the imaged object lead to a number of challenges in the image reconstruction procedure. In this work we describe our approach to obtaining accurate relative stopping power maps in the shortest amount of time.

We evaluated the overall setup accuracy for the On-Board Imager (OBI, Varian Medical Systems Inc., Palo Alto, CA, USA), with attention to the laser, the gantry, and operator performance. We let experienced technicians place the marker block on the couch using a lock bar system, with alignment to the isocenter of the laser, every morning. A pair of radiographic images of the marker block was acquired at 0 and 270 angles to the kV arm to correct the position using a 2D/2D matching technique. Once the desired match was achieved, the couch was moved remotely to correct the setup error and the parameters were saved. The average for the vertical and the longitudinal displacements were 0.65 mm and 0.66 mm, and 0.01 mm for the lateral displacement. The average for the vertical and longitudinal displacements were statistically significant at the 0.05 level (p value=0.000 for both), while the p value for the lateral direction was 0.829. These results show that the tendencies to displacement i...

The ImagingRing, a novel cone-beam computed tomography (CBCT) imaging device with independently rotatable x-ray source and flat-panel detector arms, allows for planar and CBCT acquisitions of arbitrary regions inside the device’s cylindrical imaging volume. Due to its special geometry, an adjustment of standard methods for generating flat-field planar images is required in order to fit the particular geometric conditions. This work gives an overview of the current implementation of the flat-field correction pipeline for the ImagingRing as well as an outlook to further planned improvements for CBCT enhancing quality.

In external beam radiotherapy of prostate cancer, the consideration of various systematic error types leads to wide treatment margins compromising normal tissue tolerance. We investigated if systematic set-up errors can be reduced by a set of initial image-guided radiotherapy (IGRT) sessions. Patients and Methods: 27 patients received daily IGRT resulting in a set of 882 cone-beam computed tomographies (CBCTs). After matching to bony structures, we analyzed the dimensions of remaining systematic errors from zero up to six initial IGRT sessions and aimed at a restriction of daily IGRT for 10% of all patients. For threshold definition, we determined the standard deviations (SD) of the shift corrections and selected patients out of this range for daily image guidance. To calculate total treatment margins, we demanded for a cumulative clinical target volume (CTV) coverage of at least 95% of the specified dose in 90% of all patients. Results: The gain of accuracy was largest during the first three IGRTs. In order to match precision and workload criteria, thresholds for the SD of the corrections of 3.5 mm, 2.0 mm and 4.5 mm in the left-right (L-R), cranial-caudal (C-C), and anterior-posterior (A-P) direction, respectively, were identified. Including all other error types, the total margins added to the CTV amounted to 8.6 mm in L-R, 10.4 mm in C-C, and 14.4 mm in A-P direction. Conclusion: Only initially performed IGRT might be helpful for eliminating gross systematic errors especially after virtual simulation. However, even with daily IGRT performance, a substantial PTV margin reduction is only achievable by matching internal markers instead of bony anatomical structures.

Schedule overview Thursday, 2 nd June 2016 Conference room-PAN, 17/19 Wieniawskiego Street 11.00-16.30 Workshop I: Brachytherapy in clinical practice (Applied methodology and protocols)-Elekta 12.30-12.45 CT planning in HDR brachytherapy of cervical cancer patients Agnieszka Żółciak-Siwińska (Warszawa, Poland) 12.45-13.00 Complementary lip cancer brachytherapy

Background: Cancer is one of the most dreadful diseases all over the world that can cause death. Cancer could be treated with different methods such as surgery, chemotherapy or radiotherapy. Methodology: In this review study, various techniques in cancer treatment especially radiotherapy modalities including three dimensional radiation therapy, intensity modulated radiation therapy, image guided radiation therapy, intra operative radiotherapy, stereotactic methods and brachytherapy are reviewed and discussed. Conclusion: Over recent years, radiotherapy techniques have been greatly developed which create various suitable conditions for the treatment of different cancers while sparing normal tissues. As the radiotherapy techniques developed, tumor covering and precision on dose delivery increased.