A new imaging mode based on X-ray CT as prior image and sparsely sampled projections for rapid clinical proton CT

Proton computed tomography(CT)has a distinct practical significance in clinical applications.It eliminates 3–5%errors caused by the transformation of Hounsfield unit(HU)to relative stopping power(RSP)values when using X-ray CT for positioning and treatment planning systems(TPSs).Following the development of FLASH proton therapy,there are increased requirements for accurate and rapid positioning in TPSs.Thus,a new rapid proton CT imaging mode is proposed based on sparsely sampled projections.The proton beam was boosted to 350 MeV by a compact proton linear accelerator(LINAC).In this study,the comparisons of the proton scattering with the energy of 350 MeV and 230 MeV are conducted based on GEANT4 simulations.As the sparsely sampled information associated with beam acquisitions at 12 angles is not enough for reconstruction,X-ray CT is used as a prior image.The RSP map generated by converting the X-ray CT was constructed based on Monte Carlo simulations.Considering the estimation of the most likely path(MLP),the prior image-constrained compressed sensing(PICCS)algorithm is used to reconstruct images from two different phantoms using sparse proton projections of 350 MeV parallel proton beam.The results show that it is feasible to realize the proton image reconstruction with the rapid proton CT imaging proposed in this paper.It can produce RSP maps with much higher accuracy for TPSs and fast positioning to achieve ultra-fast imaging for real-time image-guided radiotherapy(IGRT)in clinical proton therapy applications.

Three dimensional image-based brachytherapy:evaluating the true impact on treatment outcome

Imaging is now a well established component of radiation therapy with all major imaging modalities represented and numerous examples in which these modalities have been used in treatment planning to allow increased accuracy and precision in the delivery of dose.While these developments are well established since a fairly long time for external beam radiotherapy,they are yet to be firmly established in many brachytherapy units all over the world particularly in the developing countries.We will review the basic principles of image-based brachytherapy and explore the potential clinical opportunities behind this innovative technique.

Stereotactic guidance for navigated percutaneous sacroiliac joint fusion

Arthrodesis of the sacroiliac joint（SIJ） for surgical treatment of SIJ dysfunction has regained interest among spine specialists.Current techniques described in the literature most often utilize intraoperative fluoroscopy to aid in implant placement;however,image guidance for SIJ fusion may allow for minimally invasive percutaneous instrumentation with more precise implant placement.In the following cases,we performed percutaneous stereotactic navigated sacroiliac instrumentation using O-arm^（？）multidimensional surgical imaging with StealthStation^（？）navigation（Medtronic,Inc.Minneapolis,MN）.Patients were positioned prone and an image-guidance reference frame was placed contralateral to the surgical site.O-arm^（？） integrated with StealthStation^（？） allowed immediate autoregistration.The skin incision was planned with an image-guidance probe.An image-guided awl,drill and tap were utilized to choose a starting point and trajectory.Threaded titanium cage（s） packed with autograft and/or allograft were then placed.O-arm^（？） image-guidance allowed for implant placement in the SIJ with a small skin incision.However,we could not track the cage depth position with our current system,and in one patient,the SIJ cage had to be revised secondary to the anterior breach of sacrum.

Method for Obtaining Line-of-Sight Rate with a Strap-down Imaging Guidance

In the strap-down TV guidance system, the line-of-sight（LOS） rate can not be obtained frora the measured information, the math platform to select missile attitude information must be set up. The LOS rate selecting models based on the missile attitude angle and the rate gyro are set up, the influencing factor and the extracting precision of LOS rate are emulated and analyzed.

Image-guided radiation therapy: basic concepts and clinical potentials

The adaptation and integration of imaging into the process of cancer detection, diagnosis, and intervention is an area of medicine that is undergoing extremely rapid development. Radiation therapy is a prime example of this change. While the objectives of these developments are clear, they raise numerous issues regarding the skills and resources that assure these technologies are appropriately integrated and applied. We will explore the basic concepts related to image guidance in various radiotherapy-related procedures with special emphasis on the clinical potentials of this impressive technology.

Navigated liver surgery:State of the art and future perspectives

Background:In recent years,the development of digital imaging technology has had a significant influence in liver surgery.The ability to obtain a 3-dimensional(3D)visualization of the liver anatomy has provided surgery with virtual reality of simulation 3D computer models,3D printing models and more recently holograms and augmented reality(when virtual reality knowledge is superimposed onto reality).In addition,the utilization of real-time fluorescent imaging techniques based on indocyanine green(ICG)uptake allows clinicians to precisely delineate the liver anatomy and/or tumors within the parenchyma,applying the knowledge obtained preoperatively through digital imaging.The combination of both has transformed the abstract thinking until now based on 2D imaging into a 3D preoperative conception(virtual reality),enhanced with real-time visualization of the fluorescent liver structures,effectively facilitating intraoperative navigated liver surgery(augmented reality).Data sources:A literature search was performed from inception until January 2021 in MEDLINE(Pub Med),Embase,Cochrane library and database for systematic reviews(CDSR),Google Scholar,and National Institute for Health and Clinical Excellence(NICE)databases.Results:Fifty-one pertinent articles were retrieved and included.The different types of digital imaging technologies and the real-time navigated liver surgery were estimated and compared.Conclusions:ICG fluorescent imaging techniques can contribute essentially to the real-time definition of liver segments;as a result,precise hepatic resection can be guided by the presence of fluorescence.Furthermore,3D models can help essentially to further advancing of precision in hepatic surgery by permitting estimation of liver volume and functional liver remnant,delineation of resection lines along the liver segments and evaluation of tumor margins.In liver transplantation and especially in living donor liver transplantation(LDLT),3D printed models of the donor’s liver and models of the recipient’s hilar anatomy can contribute further to improving the results.In particular,pediatric LDLT abdominal cavity models can help to manage the largest challenge of this procedure,namely large-for-size syndrome.

Functional micro/nanobubbles for ultrasound medicine and visualizable guidance

Chemically functionalized gas-filled bubbles with a versatile micro/nano-sized scale have witnessed a long history of developments and emerging applications in disease diagnosis and treatments.In combination with ultrasound and image-guidance,micro/nanobubbles have been endowed with the capabilities of biomedical imaging,drug delivery,gene transfection and diseaseoriented therapy.As an external stimulus,ultrasound(US)-mediated targeting treatments have been achieving unprecedented efficiency.Nowadays,US is playing a crucial role in visualizing biological/pathological changes in lives as a reliable imaging technique and a powerful therapeutic tool.This review retrospects the history of ultrasound,the chemistry of functionalized agents and summarizes recent advancements of functional micro/nanobubbles as US contrast agents in preclinical and transclinical research.Latest ultrasound-based treatment modalities in association with functional micro/nanobubbles have been highlighted as their great potentials for disease precision therapy.It is believed that these state-of-the-art micro/nanobubbles will become a booster for ultrasound medicine and visualizable guidance to serve future human healthcare in a more comprehensive and practical manner.

Ultrasound-guided prostate percutaneous intervention robot system and calibration by informative particle swarm optimization

Applying a robot system in ultrasound-guided percutaneous intervention is an effective approach for prostate cancer diagnosis and treatment.The limited space for robot manipulation restricts structure volume and motion.In this paper,an 8-degree-of-freedom robot system is proposed for ultrasound probe manipulation,needle positioning,and needle insertion.A novel parallel structure is employed in the robot system for space saving,structural rigidity,and collision avoidance.The particle swarm optimization method based on informative value is proposed for kinematic parameter identification to calibrate the parallel structure accurately.The method identifies parameters in the modified kinematic model stepwise according to parameter discernibility.Verification experiments prove that the robot system can realize motions needed in targeting.By applying the calibration method,a reasonable,reliable forward kinematic model is built,and the average errors can be limited to 0.963 and 1.846 mm for insertion point and target point,respectively.

Single W18O49 nanowires： A multifunctional nanoplatform for computed tomography imaging and photothermal/ photodynamic/radiation synergistic cancer therapy

Combination therapy is a promising cancer treatment strategy that is usually based on the utilization of complicated nanostructures with multiple components functioning as photo-thermal energy transducers, photo-sensitizers, or dose intensifiers for phototherma! therapy （PTT）, photodynamic therapy （PDT）, or radiation therapy （RT）. In this study, ultrathin tungsten oxide nanowires （W18O49） were synthesized using a solvothermal approach and examined as a multifunctional theranostic nanoplatform. In vitro and in vivo analyses demonstrated that these nanowires could induce extensive heat- and singlet oxygen-mediated damage to cancer cells under 980 nm near infrared （NIR）-laser excitation. They were also shown to function as radiation dose intensifying agents that enhance irradiative energy deposition locally and selectively during radiation therapy. Compared to NIR-induced PTT/PDT and RT alone, W18O49 - based synergistic tri-modal therapy eradicated xenograft tumors and no recurrence was observed within a 9-month follow up. Moreover, the strong X-ray attenuation ability of the tungsten element （Z = 74, 4.438 cm^2·g^-1, 100 KeV） qualified these nanowires as excellent contrast agents in X-ray-based imaging, such as diagnostic computed tomography （CT） and cone-beam CT for image-guided radiation therapy. Toxicity studies demonstrated minimal adverse effects on the hematologic system and major organs of mice within one month. In conclusion, these nanowires have shown significant potential for cancer therapy with inherent image guidance and synergistic effects from phototherapy and radiation therapy, which warrants further investigation.