Image-guided Methods Research Articles

The TROG 15.01 stereotactic prostate adaptive radiotherapy utilizing kilovoltage intrafraction monitoring (SPARK) clinical trial database.

The US National Institutes of Health state that Sharing of clinical trial data has great potential to accelerate scientific progress and ultimately improve public health by generating better evidence on the safety and effectiveness of therapies for patients (https://www.ncbi.nlm.nih.gov/books/NBK285999/ accessed 2024-01-24.). Aligned with this initiative, the Trial Management Committee of the Trans-Tasman Radiation Oncology Group (TROG) 15.01 Stereotactic Prostate Adaptive Radiotherapy utilizing Kilovoltage intrafraction monitoring (KIM) (SPARK) clinical trial supported the public sharing of the clinical trial data. The data originate from the TROG 15.01 SPARK clinical trial. The SPARK trial was a phase II prospective multi-institutional clinical trial (NCT02397317). The aim of the SPARK clinical trial was to measure the geometric and dosimetric cancer targeting accuracy achieved with a real-time image-guided radiotherapy technology named KIM for 48 prostate cancer patients treated in 5 treatment sessions. During treatment, real-time tumor translational and rotational motion were determined from x-ray images using the KIM technology. A dose reconstruction method was used to evaluate the dose delivered to the target and organs-at-risk. Patient-reported outcomes and toxicity data were monitored up to 2 years after the completion of the treatment. The dataset contains planning CT images, treatment plans, structure sets, planned and motion-included dose-volume histograms, intrafraction kilovoltage, and megavoltage projection images, tumor translational and rotational motion determined by KIM, tumor motion ground truth data, the linear accelerator trajectory traces, and patient treatment outcomes. The dataset is publicly hosted by the University of Sydney eScholarship Repository at https://doi.org/10.25910/qg5d-6058. The 3.6Tb dataset, with approximately 1 million patient images, could be used for a variety of applications, including the development of real-time image-guided methods, adaptation strategies, tumor, and normal tissue control modeling, and prostate-specific antigen kinetics.

Overview of Therapeutic Ultrasound Applications and Safety Considerations: 2024 Update.

A 2012 review of therapeutic ultrasound was published to educate researchers and physicians on potential applications and concerns for unintended bioeffects (doi: 10.7863/jum.2012.31.4.623). This review serves as an update to the parent article, highlighting advances in therapeutic ultrasound over the past 12 years. In addition to general mechanisms for bioeffects produced by therapeutic ultrasound, current applications, and the pre-clinical and clinical stages are outlined. An overview is provided for image guidance methods to monitor and assess treatment progress. Finally, other topics relevant for the translation of therapeutic ultrasound are discussed, including computational modeling, tissue-mimicking phantoms, and quality assurance protocols.

Sensitivity Response Analysis of Optical Surface Monitoring Systems Using the Fitzpatrick Scale: A Phantom Study

PurposeOptical Surface Monitoring systems (OSMS) have gained substantial attention in modern radiotherapy, specifically in the context of Surface Guided Radiation Therapy (SGRT) which offers real-time patient surface monitoring, ensuring accurate and effective radiotherapy treatments. The aim of this paper is to evaluate the OSMS camera sensitivity towards different skin tones, categorized according to the Fitzpatrick scale, a universal classification of human skin tones, using a phantom. Methods and MaterialThe study utilized Catalyst and SentinelTM OSMS systems (C-Rad, Uppsala, Sweden). The Alderson RANDO Female Pelvis phantom, located at the isocenter in CT simulation and treatment rooms, served as an experimental subject. Eighteen skin tone matching cotton cloths, selected based on Von Luschan's chromatic and Fitzpatrick scales, were wrapped around the phantom for sensitivity evaluation. Camera sensitivity was optimized by adjusting threshold/gain (100-600%) and integration time during individual scans in both rooms. Temporal response analysis spanned two months, with sixteen measurements for each OSMS taken in varying light conditions. ResultsThe OSMS systems successfully detected the surface of cloth-covered phantoms with varying mean (standard deviation) integration times: 550 (34) to 950 (43) μs for the Sentinel system and 2300 (71) to12000 (400) μs for the Catalyst system. The sensitivity parameters differed for each skin tone, with lighter skin requiring shorter integration times and gain/threshold values. Darker skin tones necessitated higher parameters for optimal surface images. The reliability of the systems declined with excessive parameters, leading to noise and compromised accuracy in patient positioning. ConclusionsOptimized sensitivity parameters tailored to individual skin tones are crucial for effective real-time patient surface monitoring in radiation therapy, as variations in skin colour can affect the accuracy of measurements. The precision of skin colour measurements in OSMS relies on carefully adjusting camera sensitivity parameters. However, careful consideration is essential, as larger values are required for darker skin tones, compromising reliability. This suggests the need for exploring alternative image guidance methods for patients with darker skin tones.

Influence of various pilot hole profiles on pedicle screw fixation strength in minimally invasive and traditional spinal surgery: a comparative biomechanical study.

Despite advancements in pedicle screw design and surgical techniques, the standard steps for inserting pedicle screws still need to follow a set of fixed procedures. The first step, known as establishing a pilot hole, also referred to as a pre-drilled hole, is crucial for ensuring screw insertion accuracy. In different surgical approaches, such as minimally invasive or traditional surgery, the method of creating pilot holes varies, resulting in different pilot hole profiles, including variations in size and shape. The aim of this study is to evaluate the biomechanical properties of different pilot hole profiles corresponding to various surgical approaches. Commercially available synthetic L4 vertebrae with a density of 0.16g/cc were utilized as substitutes for human bone. Four different pilot hole profiles were created using a 3.0mm cylindrical bone biopsy needle, 3.6mm cylindrical drill, 3.2-5.0mm conical drill, and 3.2-5.0mm conical curette for simulating various minimally invasive and traditional spinal surgeries. Two frequently employed screw shapes, namely, cylindrical and conical, were selected. Following specimen preparation, screw pullout tests were performed using a material test machine, and statistical analysis was applied to compare the mean maximal pullout strength of each configuration. Conical and cylindrical screws in these four pilot hole configurations showed similar trends, with the mean maximal pullout strength ranking from high to low as follows: 3.0mm cylindrical biopsy needle, 3.6mm cylindrical drill bit, 3.2-5.0mm conical curette, and 3.2-5.0mm conical drill bit. Conical screws generally exhibited a greater mean maximal pullout strength than cylindrical screws in three of the four different pilot hole configurations. In the groups with conical pilot holes, created with a 3.2-5.0mm drill bit and 3.2-5.0mm curette, both conical screws exhibited a greater mean maximal pullout strength than did cylindrical screws. The strength of this study lies in its comprehensive comparison of the impact of various pilot hole profiles commonly used in clinical procedures on screw fixation stability, a topic rarely reported in the literature. Our results demonstrated that pilot holes created for minimally invasive surgery using image-guided techniques exhibit superior pullout strength compared to those utilized in traditional surgery. Therefore, we recommend prioritizing minimally invasive surgery when screw implantation is anticipated to be difficult or there is a specific need for stronger screw fixation. When opting for traditional surgery, image-guided methods may help establish smaller pilot holes and increase screw fixation strength.

Two-dimensional and Three-dimensional Image-guided Evaluation of Patient Positioning for Intensity-modulated Radiation Therapy of Head and Neck Cancer

Patient positioning accuracy is critical in radiation therapy, especially in intensity-modulated radiation therapy (IMRT) for head and neck cancer (HNC), as it can affect treatment effectiveness and safety. This retrospective study aimed to evaluate the accuracy of patient positioning techniques and compare the effectiveness of using multiple image-guided (IG) methods for IG-IMRT of HNC. Cone-beam computed tomography (CBCT) and kV-planar imaging (OBI) collected 3240 treatment couch coordinates in three translational directions from 60 HNC patients undergoing IMRT. Inter-fraction errors were assessed by registering the scans to the planning CT, and the population systematic set-up error (Σ), random error (σ), and planning target volume (PTV) margin were calculated. The results between OBI and CBCT were analyzed and compared using one-way ANOVA. The findings demonstrated that more than 80% of the image-guided patient positioning set-ups were acceptable. The mean couch displacement for image-guided techniques was negligible in all translational directions using OBI and CBCT. However, the PTV margin for both methods was more than 0.5 cm, except for the CBCTA-P direction. This study highlights the effectiveness of OBI and CBCT as modalities for evaluating and improving the accuracy of IMRT in HNC patients. Determination of the systematic and random errors and calculating the optimal PTV margin without rematching images can help improve the precision of patient positioning and ultimately lead to better treatment outcomes.

Automatic breach detection during spine pedicle drilling based on vibroacoustic sensing

Pedicle drilling is a complex and critical spinal surgery task. Detecting breach or penetration of the surgical tool to the cortical wall during pilot-hole drilling is essential to avoid damage to vital anatomical structures adjacent to the pedicle, such as the spinal cord, blood vessels, and nerves. Currently, the guidance of pedicle drilling is done using image-guided methods that are radiation intensive and limited to the preoperative information. This work proposes a new radiation-free breach detection algorithm leveraging a non-visual sensor setup in combination with deep learning approach. Multiple vibroacoustic sensors, such as a contact microphone, a free-field microphone, a tri-axial accelerometer, a uni-axial accelerometer, and an optical tracking system were integrated into the setup. Data were collected on four cadaveric human spines, ranging from L5 to T10. An experienced spine surgeon drilled the pedicles relying on optical navigation. A new automatic labeling method based on the tracking data was introduced. Labeled data was subsequently fed to the network in mel-spectrograms, classifying the data into breach and non-breach. Different sensor types, sensor positioning, and their combinations were evaluated. The best results in breach recall for individual sensors could be achieved using contact microphones attached to the dorsal skin (85.8%) and uni-axial accelerometers clamped to the spinous process of the drilled vertebra (81.0%). The best-performing data fusion model combined the latter two sensors with a breach recall of 98%. The proposed method shows the great potential of non-visual sensor fusion for avoiding screw misplacement and accidental bone breaches during pedicle drilling and could be extended to further surgical applications.

Intensity-Modulated Radiation Therapy for Early-Stage Squamous Cell Carcinoma of the Glottic Larynx: A Systematic Review and Meta-Analysis

Early-stage squamous cell carcinoma of the glottic larynx is commonly treated with 2-dimensional or 3-dimensional conventional radiation therapy (CRT). Despite its use in other head and neck cancers, intensity-modulated radiation therapy (IMRT) remains controversial in this patient population. A systematic review was performed by querying 3 databases (Pubmed, Embase, Web of Science) for articles published between December 1, 2000 and September 2, 2022. Included studies reported outcomes in at least 10 patients treated with IMRT for early-stage glottic cancer. Data were extracted and reported following PRISMA standards. Pooled outcomes were estimated using random-effects models. Primary outcome was the rate of local failure (LF) following IMRT. Secondary outcomes included rates of regional failure (RF) following IMRT and rates of LF and RF following CRT. A total of 15 studies (14 retrospective, 1 prospective) consisting of 2083 patients were identified. IMRT was used in 873 patients (64% T1, 28% T2). Multiple treatment (partial larynx, single vocal cord carotid sparing) and image-guided radiation therapy techniques were used. The pooled crude rate of LF was 7.6% (95% confidence inverval [CI], 3.6%-11.5%) and actuarial LF rates at 3 and 5 years were 6.3% (95% CI, 2.2%-10.3%) and 9.0% (95% CI, 4.4%-13.5%), respectively. The pooled crude rate of RF after IMRT was 1.5% (95% CI, 0.5%-2.5%). On metaregression analysis, increased rate of LF was significantly associated with T2 disease (P < .001) and grade 2 to 3 histology (P < .001). Treatment with CRT was reported in 738 patients (76% T1, 22% T2). Among the studies reporting outcomes of both modalities, there was no significant difference in LF (log odds ratio; P=.12) or RF (log odds ratio; P=.58) between IMRT or CRT. In patients with early-stage glottic cancer, retrospective data suggests local and regional control are similar for patients treated with IMRT and CRT. Additional prospective studies with uniform methods of volume delineation and image guidance are needed to confirm the efficacy of IMRT.

Image-Guided Proton Therapy: A Comprehensive Review.

Image guidance for radiation therapy can improve the accuracy of the delivery of radiation, leading to an improved therapeutic ratio. Proton radiation is able to deliver a highly conformal dose to a target due to its advantageous dosimetric properties, including the Bragg peak. Proton therapy established the standard for daily image guidance as a means of minimizing uncertainties associated with proton treatment. With the increasing adoption of the use of proton therapy over time, image guidance systems for this modality have been changing. The unique properties of proton radiation present a number of differences in image guidance from photon therapy. This paper describes CT and MRI-based simulation and methods of daily image guidance. Developments in dose-guided radiation, upright treatment, and FLASH RT are discussed as well.

A radio- and fluorescently labelled tracer for imaging and quantification of bacterial infection on orthopaedic prostheses

Arthroplasty surgery of the knee and hip is performed in two to three million patients annually. Periprosthetic joint infections occur in 4% of these patients. Debridement, antibiotics, and implant retention (DAIR) surgery aimed at cleaning the infected prosthesis often fails, subsequently requiring invasive revision of the complete prosthetic reconstruction. Infection-specific imaging may help to guide DAIR. In this study, we evaluated a bacteria-specific hybrid tracer (99mTc-UBI29-41-Cy5) and its ability to visualize the bacterial load on femoral implants using clinical-grade image guidance methods. 99mTc-UBI29-41-Cy5 specificity for Stapylococcus aureus was assessed in vitro using fluorescence confocal imaging. Topical administration was used to highlight the location of S. aureus cultured on femoral prostheses using fluorescence imaging and freehand single photon emission CT (fhSPECT) scans. Gamma counting and fhSPECT were used to quantify the bacterial load and monitor cleaning with chlorhexidine. Microbiological culturing helped to relate the imaging findings with the number of (remaining) bacteria. Bacteria could be effectively stained in vitro and on prostheses, irrespective of the presence of biofilm. Infected prostheses revealed bacterial presence on the transition zone between the head and neck, and in the screw hole. Qualitative 2D fluorescence images could be complemented with quantitative 3D fhSPECT scans. Despite thorough chlorhexidine treatments, 28% to 44% of the signal remained present in the locations of the infection that were identified using imaging, which included 500 to 2,000 viable bacteria. The hybrid tracer 99mTc-UBI29-41-Cy5 allowed effective bacterial staining. Qualitative real-time fluorescence guidance could be effectively combined with nuclear imaging that enables quantitative monitoring of the effectiveness of cleaning strategies.Cite this article: Bone Joint Res2023;12(1):72-79.

A Comprehensive Survey of Depth Completion Approaches.

Depth maps produced by LiDAR-based approaches are sparse. Even high-end LiDAR sensors produce highly sparse depth maps, which are also noisy around the object boundaries. Depth completion is the task of generating a dense depth map from a sparse depth map. While the earlier approaches focused on directly completing this sparsity from the sparse depth maps, modern techniques use RGB images as a guidance tool to resolve this problem. Whilst many others rely on affinity matrices for depth completion. Based on these approaches, we have divided the literature into two major categories; unguided methods and image-guided methods. The latter is further subdivided into multi-branch and spatial propagation networks. The multi-branch networks further have a sub-category named image-guided filtering. In this paper, for the first time ever we present a comprehensive survey of depth completion methods. We present a novel taxonomy of depth completion approaches, review in detail different state-of-the-art techniques within each category for depth completion of LiDAR data, and provide quantitative results for the approaches on KITTI and NYUv2 depth completion benchmark datasets.

Comparing fluoroscopic versus ultrasound guidance in glenohumeral joint aspiration.

Joint aspiration is a common technique used to aid in the diagnosis of glenohumeral pathology. Fluoroscopy and ultrasound are both used as image-guidance methods to increase the accuracy of the procedure. There are no prior studies comparing the ability of these two methods to obtain joint fluid. To evaluate whether fluoroscopy or ultrasound-image guidance more often obtains fluid from the glenohumeral joint and which technique obtains a greater amount of fluid. Retrospective cohort study. Single academic orthopedic clinic. A total of 206 patients undergoing glenohumeral aspiration, generally to rule out infection. Fluoroscopic- or ultrasound-guided joint aspirations, performed by numerous physicians. Primary was the successful aspiration of at least 0.1mL of joint fluid; secondary was the total amount of joint fluid obtained. There was no significant difference in rate of successful aspirations between ultrasound (69.4% successful; 95% confidence interval [CI]=54.4%, 84.5%) and fluoroscopy (70.6% successful; 95% CI=63.7%, 77.4%). The amounts of fluid obtained by fluoroscopy and ultrasound did not differ significantly (p=.349; mean ± standard deviation [SD]=7.1 ± 12.6 vs. 10.0 ± 16.8mL; median [interquartile range [IQR]=3 [7] vs. 5 [8.75] mL). Sub-analysis showed that significantly more fluid was obtained with fluoroscopy in patients with a >35 body mass index (BMI) (adjusted mean=7.9mL; 95% CI=4.3, 11.5) when compared with ultrasound (2.3mL; 95% CI=0.6, 4.0). Fluoroscopic- and ultrasound-guided aspirations of the glenohumeral joint demonstrate similar success in obtaining fluid. For nonobese patients, ultrasound guidance is typically less expensive, office-based, less uncomfortable, and allows for dynamic visualization. For obese patients, fluoroscopy appears to have an advantage with respect to the amount of fluid obtained. Prospective studies are warranted to make more robust conclusions.

SyncMRT: a solution to image-guided synchrotron radiotherapy for quality assurance and pre-clinical trials.

In this work, a new image guidance system and protocols for delivering image-guided radiotherapy (IGRT) on the Imaging and Medical Beamline (IMBL) at the ANSTO Australian Synchrotron are introduced. The image guidance methods used and the resulting accuracy of tumour alignment in in vivo experiments are often under-reported. Image guidance tasks are often complex, time-consuming and prone to errors. If unchecked, they may result in potential mis-treatments. We introduce SyncMRT, a software package that provides a simple, image guidance tool-kit for aligning samples to the synchrotron beam. We have demonstrated sub-millimetre alignment using SyncMRT and the small-animal irradiation platform (the DynamicMRT system) on the IMBL. SyncMRT has become the standard for carrying out IGRT treatments on the IMBL and has been used in all pre-clinical radiotherapy experiments since 2017. Further, we introduce two quality assurance (QA) protocols to synchrotron radiotherapy on the IMBL: the Winston-Lutz test and hidden target test. It is shown that the presented QA tests are appropriate for picking up geometrical setup errors and assessing the end-to-end accuracy of the image guidance process. Together, these tools make image guidance easier and provide a mechanism for reporting the geometric accuracy of synchrotron-based IGRT treatments. Importantly, this work is scalable to other delivery systems, and is in continual development to support the upcoming veterinary radiotherapy trials on the IMBL.

Real-Time Ultrasound Detection of Breast Microcalcifications Using Multifocus Twinkling Artifact Imaging.

Detecting microcalcifications (MCs) in real time is important in the guidance of many breast biopsies. Due to its capability in visualizing biopsy needles without radiation hazards, ultrasound imaging is preferred over X-ray mammography, but it suffers from low sensitivity in detecting MCs. Here, we present a new nonionizing method based on real-time multifocus twinkling artifact (MF-TA) imaging for reliably detecting MCs. Our approach exploits time-varying TAs arising from acoustic random scattering on MCs with rough or irregular surfaces. To obtain the increased intensity of the TAs from MCs, in MF-TA, acoustic transmit parameters, such as the transmit frequency, the number of focuses and f-number, were optimized by investigating acoustical characteristics of MCs. A real-time MF-TA imaging sequence was developed and implemented on a programmable ultrasound research system, and it was controlled with a graphical user interface during real-time scanning. From an in-house 3D phantom and ex vivo breast specimen studies, the MF-TA method showed outstanding visibility and high-sensitivity detection for MCs regardless of their distribution or the background tissue. These results demonstrated that this nonionizing, noninvasive imaging technique has the potential to be one of effective image-guidance methods for breast biopsy procedures.

Minimalno invazivne metode za lečenje tiroidnih nodusa i karcinoma

Thyroid nodules (TN) are present in about half of the population. About 5% of all nodules are malignant. Image-guided methods for the treatment of TN are becoming a significant alternative to surgery. Percutaneous ethanol ablation (PEA) is effective in the treatment of thyroid cysts, and neck lymph node metastases. Percutaneous laser ablation (PLA) significantly reduces the size of the nodules and improves subjective symptoms. The adverse effects of PEA are rare, transitory, and mild. Radiofrequency ablation (RFA) is effective for nodules of all sizes and compositions. The major complications of RFA are rare and transient. Microwave ablation is also effective in the treatment of thyroid nodules with rare major complications. High-intensity focused ultrasound (HIFU) is a transcutaneous method. It is effective in the treatment of thyroid nodules, and complications are rare. Graves' hyperthyroidism was also treated with HIFU. As thermal ablation (TA ) methods are becoming more popular in 2020, the European Thyroid Association published clinical practice guidelines for the use of image-guided ablation in benign thyroid nodules. A meta-analysis showed that low-risk papillary thyroid microcarcinoma recurrences after TA treatment are rare, as are complications. As the TA methods are acceptable for the treatment of the low-risk papillary thyroid carcinoma European Thyroid Association and Cardiovascular and Interventional Radiological Society of Europe issued clinical practice guidelines for the use of minimally invasive treatments in malignant thyroid lesions. Image-guided treatments for thyroid nodules and cancer are here to stay. Their use will expand and become part of routine clinical practice.

Image-guided ray tracing and its applications

Eikonal solvers have important applications in seismic data processing and inversion, the so-called image-guided methods. To this day, in image-guided applications, the solution of the eikonal equation is implemented using partial-differential-equation solvers, such as fast-marching or fast-sweeping methods. We have found that alternatively, one can numerically integrate the dynamic Hamiltonian system defined by the image-guided eikonal equation and reconstruct the solution with image-guided rays. We evaluate interesting applications of image-guided ray tracing to seismic data processing, demonstrating the use of the resulting rays in image-guided interpolation and smoothing, well-log interpolation, image flattening, and residual-moveout picking. Some of these applications make use of properties of the ray-tracing system that are not directly obtained by eikonal solvers, such as ray position, ray density, wavefront curvature, and ray curvature. These ray properties open space for a different set of applications of the image-guided eikonal equation, beyond the original motivation of accelerating the construction of minimum distance tables. We stress that image-guided ray tracing is an embarrassingly parallel problem that makes its implementation highly efficient on massively parallel platforms. Image-guided ray tracing is advantageous for most applications involving the tracking of seismic events and imaging-guided interpolation. Our numerical experiments using synthetic and real data sets indicate the efficiency and robustness of image-guided rays for the selected applications.

3D dosimetric validation of ultrasound-guided radiotherapy with a dynamically deformable abdominal phantom.

The purpose of this study was to dosimetrically benchmark gel dosimetry measurements in a dynamically deformable abdominal phantom for intrafraction image guidance through a multi-dosimeter comparison. Once benchmarked, the study aimed to perform a proof-of-principle study for validation measurements of an ultrasound image-guided radiotherapy delivery system. The phantom was dosimetrically benchmarked by delivering a liver VMAT plan and measuring the 3D dose distribution with DEFGEL dosimeters. Measured doses were compared to the treatment planning system and measurements acquired with radiochromic film and an ion chamber. The ultrasound image guidance validation was performed for a hands-free ultrasound transducer for the tracking of liver motion during treatment. Gel dosimeters were compared to the TPS and film measurements, showing good qualitative dose distribution matches, low γ values through most of the high dose region, and average 3%/5 mm γ-analysis pass rates of 99.2%(0.8%) and 90.1%(0.8%), respectively. Gel dosimeter measurements matched ion chamber measurements within 3%. The image guidance validation study showed the measurement of the treatment delivery improvements due to the inclusion of the ultrasound image guidance system. Good qualitative matching of dose distributions and improvements of the γ-analysis results were observed for the ultrasound-gated dosimeter compared to the ungated dosimeter. DEFGEL dosimeters in phantom showed good agreement with the planned dose and other dosimeters for dosimetric benchmarking. Ultrasound image guidance validation measurements showed good proof-of-principle of the utility of the phantom system as a method of validating ultrasound-based image guidance systems and potentially other image guidance methods.

Accuracy of Pedicle Screw Placement Methods in Pediatrics and Adolescents Spinal Surgery: A Systematic Review and Meta-Analysis.

Study Design:Systematic review and meta-analysis.Objective:Various methods of pedicle screw (PS) placement in spinal fusion surgery existed, which can be grouped into conventional freehand (FH), modified freehand (MF), and image-guided methods (including fluoroscopy-based navigation (FL), computed tomography-based navigation (CT-nav), robot-assisted (RA), and ultrasound-guided (UG)). However, the literature showed mixed findings regarding their accuracy and complications. This review aimed to discover which method of PS placement has the highest accuracy and lowest complication rate in pediatric and adolescent spinal fusion surgery.Methods:A comprehensive search in MEDLINE (PubMed), EMBASE (OVID), CENTRAL, and Web of Science was conducted until May 2020 by 2 independent reviewers, followed by bias assessment with ROB 2 and ROBINS-I tools and quantification with meta-analysis. Overall evidence quality was determined with GRADE tool.Results:Four RCTs and 2 quasi-RCTs/CCTs comprising 3,830 PS placed in 291 patients (4-22 years old) were analyzed. The lowest accuracy was found in FH (78.35%) while the highest accuracy was found in MF (95.86%). MF was more accurate than FH (OR 3.34 (95% CI, 2.33-4.79), P < .00 001, I2 = 0%). Three-dimensional printed drill template (as part of MF) was more accurate than FH (OR 3.10 (95% CI, 1.98-4.86), P < .00 001, I2 = 14%). Overall, complications occurred in 5.84% of the patients with 0.34% revision rate. Complication events in MF was lower compared to FH (OR 0.47 (95% CI, 0.10-2.15), P = .33, I2 = 0%).Conclusions:Meta-analysis shows that MF is more accurate than FH in pediatric and adolescent requiring PS placement for spinal fusion surgery.

Moderate hypofractionated post-prostatectomy radiation therapy is feasible and well tolerated: experience from a single tertiary cancer centre.

Conventional post-prostatectomy radiation therapy comprises 6.5-8weeks of treatment, therefore, hypofractionated and shortened schemes arouse increasing interest. We describe our experience regarding feasibility and clinical outcome of a post-prostatectomy moderate hypofractionated image-guided radiotherapy schedule MATERIALS AND METHODS: From Oct 2015-Mar 2020, 113 patients, median age of 62years-old (range 45-76) and prostate adenocarcinoma of low risk (30%), intermediate risk (49%) and high risk (21%) were included for adjuvant (34%) or salvage radiation therapy (66%) after radical prostatectomy (RP). All patients underwent radiotherapy with image-guided IMRT/VMAT to a total dose of 62.5Gy in 2.5Gy/fraction in 25 fractions. Sixteen patients (14%) received concomitant androgen deprivation therapy. With a median follow-up of 29months (range 3-60months) all patients but three are alive. Eleven patients (10%) developed exclusive biochemical relapse while 19 patients (17%) presented macroscopically visible relapse: prostatectomy bed in two patients (2%), pelvic lymph nodes in 13 patients (11.5%) and distant metastases in four patients (4%). The 3years actuarial rates for OS, bFRS, and DMFS were 99.1, 91.1 and 91.2%, respectively. Acute and late tolerance was satisfactory. Maximal acute genitourinary (AGU) toxicity was G2 in 8% of patients; maximal acute gastrointestinal (AGI) toxicity was G2 in 3.5% of patients; maximal late genitourinary (LGU) toxicity was G3 in 1% of patients and maximal late gastrointestinal (LGI) toxicity was G2 in 2% of patients. There were no cases of severe acute or late toxicity. No relationship was found between acute or late GI/GU adverse effects and dosimetric parameters, age, presence of comorbidities or concomitant treatments. Hypofractionated radiotherapy (62.5Gy in 25 2.5Gy fractions) is feasible and well tolerated with low complication rates allowing for a moderate dose-escalation that offers encouraging clinical results for biochemical control and survival in patients with prostate cancer after radical prostatectomy.

Strengths and weaknesses of frontal versus occipital ventriculoperitoneal shunt placement: A systematic review

Excessive accumulation of cerebrospinal fluid within the brain ventricles is called hydrocephalus, which results in increased intracranial pressure preventing brain growth or causing damage to intracranial structures due to raised intracranial pressure. One of the most common treatment options for this pathology includes the placement of a ventriculoperitoneal shunt to drain the excess fluid. The location of catheterization is traditionally considered as an important factor affecting shunt survival. In this study, we aimed to systematically review all available documents to determine the advantage and superiority of frontal or occipital shunt entry points as the two main approaches. A database search was performed in PubMed, Scopus, Embase, Web of Science, Medline, Ovid, and Google Scholar using "ventriculoperitoneal", "shunt placement", and "hydrocephalus" as the main key terms. Resultant articles were screened for relevancy based on predefined inclusion and exclusion criteria by two authors independently. After excluding irrelevant documents, the data of 11 related articles consisting of 3947 patients were extracted and qualitative data synthesis and pooled analysis were performed. The results of the included studies showed that although the outcomes of a higher percentage of the total review population were in favor of frontal shunt placement, there was no significant superiority for neither of these two approaches after pooled analysis of available failure rates. Findings have shown that each approach has benefits and drawbacks, and there may be other factors such as age and valve design besides the position of shunt placement that may affect the survival rate. Also, the accuracy of shunt placement as an independent factor affects the failure rate and can be improved with various image-guidance methods to minimize shunt failure.

A review of stereotactic body radiotherapy for the spine.

Radiation therapy of the spine, as recourse for spinal tumours, is an effective method of achieving pain reduction and local control. Hypofractionated techniques like stereotactic body radiation therapy and especially stereotactic radiosurgery are quickly becoming more popular as studies are published demonstrating their superior outcomes. This review concerns aspects of spinal radiotherapy of interest to the clinical medical physicist, with a focus on stereotactic techniques. The literature surveyed is mostly from the last two decades, concentrating particularly on studies from the last few years. Clinical aspects of spinal disease are covered to give context to the development of different radiotherapy techniques and thus the changing suitability criteria of patients. The latest studies concerning the treatment pathway are reviewed and summarised-from simulation and prescription to contouring, treatment planning and treatment delivery. This then leads into a discussion of the accuracy and uncertainties surrounding different methods of immobilisation and image guidance. Treatment planning algorithms and approaches are also reviewed. Finally, we survey the most recent outcomes and statistics concerning failures, toxicity, survivability and control rates. With careful consideration of the latest literature, patients suffering from spinal disease have a good chance of positive outcomes following radiotherapy.