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This paper focuses on the use of MATLAB SimBiology (version MATLAB R2019b) as a tool for modeling, simulating, and analyzing cancer diseases. The article describes the process of building a model of cancer disease in the SimBiology Model Builder application based on a mathematical model that considers the process of tumor spread through the affected organ as an interference competition and takes into account tumor angiogenesis. An extension of the built model based on compartment modeling is presented, which simulates the ability of malignant tumors to metastasize and form new lesions. The results of simulation modeling with metastasis in the SimBiology Model Analyzer application are also presented. Secondary tumors are assumed to have the same properties as the primary lesion. There are two treatment delivery options in the model with metastasis that are considered: the implementation of constant continuous treatment using events and the implementation of discrete drug delivery using repeated or scheduled doses. In both treatment models, it is assumed that drugs are consumed only to suppress malignant cells, and their side effects are neglected. The response of tumor dynamics to treatment was simulated, and results are presented in this article. [ABSTRACT FROM AUTHOR]

Clinical trial enrollment is impeded by the significant time burden placed on research coordinators screening eligible patients. With 50,000 new cancer cases every year, the Veterans Health Administration (VHA) has made increased access for Veterans to high-quality clinical trials a priority. To aid in this effort, we worked with research coordinators to build the MPACT (Matching Patients to Accelerate Clinical Trials) platform with a goal of improving efficiency in the screening process. MPACT supports both a trial prescreening workflow and a screening workflow, employing Natural Language Processing and Data Science methods to produce reliable phenotypes of trial eligibility criteria. MPACT also has a functionality to track a patient's eligibility status over time. Qualitative feedback has been promising with users reporting a reduction in time spent on identifying eligible patients. [ABSTRACT FROM AUTHOR]

Dosimetry in nuclear medicine aims at measuring the energy absorbed by tissues due the deposited radiopharmaceuticals. It is especially important, and required by law, in radiopharmaceutical therapies, where activities and radionuclides capable of causing damage/death of the irradiated tissues are used. This is the goal for treatment of tumors; however, the radiopharmaceutical can cause severe damage to critical tissues/organs, leading to adverse side effects with consequences for the quality of life of patients. For both diagnosis and treatment, doses to non-target tissues and volumes should be as low as reasonably achievable and consistent with the radiotherapeutic purpose of the exposure. With a view to patient protection, international standards/legislation and recommendations, personalized planning and dosimetry should be performed in all patients exposed to ionizing radiation for therapeutic purposes. [ABSTRACT FROM AUTHOR]

This paper focuses on optimal control of a tumor virotherapy treatment model with external supplies such as chemo- drugs or viral injection. This model contains four subpopulation compartments: uninfected tumor cells by viruses, infected tumor cells, oncolytic viruses, and immune cells. The model is given by the system of ordinary differential equations. Chemo-drugs can slow down the growth of tumor cells and immune cells while the viral injection accelerate the growth of oncolytic viruses. We defined a positive control with maximum tolerated dosage (MTDs) as upper bound, that is, u1 and u2 represent chemotherapy drug dosage and viral injection dosage, respectively. The objective of this optimal control is to minimize tumor density and side effects of the controls. Here, we get optimal control by applying Pontryagin's Minimum Principle. Numerical simulation is implemented using the Forward-Backward Sweep Method with three strategies: u1 only, u2 only, and u1 with u2, respectively. Here, we set u1 weight much larger than u2 weight, that is, 50 and 1, respectively. The simulation shows that the third strategy (u1 with u2) has minimum side effects and density of tumors than the others controls combination. The chemo-drugs can be consumed as much as MTDs in the first quarter and need to be reduced to depletion at the end of controls. The viral injection can be consumed up to 80 percent of the MTDs at the start and needs to be reduced exponentially until the end at the period of the controls. [ABSTRACT FROM AUTHOR]

The purpose is to develop a minimally invasive gel system for long-term local administration of bisphosphonates, which has practical significance for clinical treatment of tumors. Here, the biohydrogel based on uniform tetraethylene glycol network carries polyethylene glycol modified doxorubicin prodrug for injection to patients, and doxorubicin reduces the long-term release of toxin and doxorubicin. The obtained nanocomposite hydrogel has rapid gel formation and good injectability, thus making the hydrogel easy to inject and then adapt to different types of tumors. The tetraethylene glycol hydrogel for promoting the optimal connection of adriamycin has the capability of controlling the release of adriamycin drugs as required, and achieves the effect of reducing adriamycin toxicity. The results show that these injectable hydrogels mediate the optimal release of therapeutic drugs, which will help to further develop smarter materials with customized structure and ideal functional alliance for clinical treatment of tumors. [ABSTRACT FROM AUTHOR]

Natural language processing (NLP) tools can automate the identification of cancer patients eligible for specific pathways. We developed and validated a cancer agnostic, rules-based NLP framework to extract the dimensions and measurements of several concepts from pathology and radiology reports. This framework was then efficiently and cost-effectively deployed to identify patients eligible for breast, lung, and prostate cancers clinical pathways. [ABSTRACT FROM AUTHOR]

The aim of the new Particle Therapy MasterClass (PTMC) was to develop an educational and training environment in which anyone can learn about fundamental and applied research in particle therapy. The PTMC was recently integrated into the International MasterClass 2021 online programme that attracted 1500 students from 37 institutes in 20 countries, worldwide. The PTMC focuses on the topic of cancer treatment, a particularly sensitive and socially relevant topic. The main idea is to (a) provide a basic understanding of cancer radiation therapy, (b) demonstrate that fundamental properties of particle interactions with matter, which are used for detection in physics experiments, are also the basis for treating cancer tumours; and (c) show that the same accelerator technologies are used in both, research laboratories and therapy centres. For the hands-on session, the open-source professional treatment planning software matRad is used, developed for research and training by the German Cancer Research Center – DKFZ. Ultimately, students are shown "what physics has to do with medicine" and what are the various possibilities that physics and STEM studies may open up for job opportunities in fields that are lacking expert personnel. [ABSTRACT FROM AUTHOR]

Telemedicine had a significant increase during the novel coronavirus (COVID-19) pandemic, which is still on course. In different parts of the world, healthcare units had to adapt their practice, and several assistance services were remotely delivered. The present study is a systematic review of studies that had applied telemedicine during the COVID-19 pandemic and had assessed its effects on the delivered care. We have covered a 1-year period in order to assess the initiatives developed during the pandemic time and that had already evaluated the effects of the telemedicine program that had been implemented. All the analyzed studies evidenced a positive effect of telemedicine in the treatment of different conditions, including chronic diseases, mental disorders and oncologic diseases. The real impact of the COVID-19 pandemic in the healthcare sector is still to be fully understood, and telemedicine implementation in different areas is one of its positive legacies. [ABSTRACT FROM AUTHOR]

This study was aimed at identifying how telemedicine is used for rehabilitation of patients with cancer. An electronic literature search was conducted using the PubMed database covering January 2015 to October 2020. To be included in the review, studies had to report telerehabilitation interventions for patients with cancer. Randomized controlled trials, quasi-experimental studies, as well as feasibility and usability studies were included, and reviews were excluded. Overall, 33 eligible studies were found but only 22 were considered for inclusion. After a detailed analysis, 16 studies were included. Most of the studies concluded that telehealth systems supporting physical exercise were effective to improve function, quality of life, pain, satisfaction and muscle strength. Limitations in most of the studies included non-randomized design and limited number of subjects. We conluded that more studies are needed for stronger evidence of this type of treatment and to facilitate clinical practice in this field. [ABSTRACT FROM AUTHOR]

Precision oncology is expected to improve selection of targeted therapies, tailored to individual patients and ultimately improve cancer patients' outcomes. Several cancer genetics knowledge databases have been successfully developed for such purposes, including CIViC and OncoKB, with active community-based curations and scoring of genetic-treatment evidences. Although many studies were conducted based on each knowledge base respectively, the integrative analysis across both knowledge bases remains largely unexplored. Thus, there exists an urgent need for a heterogeneous precision oncology knowledge resource with computational power to support drug repurposing discovery in a timely manner, especially for life-threatening cancer. In this pilot study, we built a heterogeneous precision oncology knowledge resource (POKR) by integrating CIViC and OncoKB, in order to incorporate unique information contained in each knowledge base and make associations amongst biomedical entities (e.g., gene, drug, disease) computable and measurable via training POKR graph embeddings. All the relevant codes, database dump files, and pre-trained POKR embeddings can be accessed through the following URL: https://github.com/shenfc/POKR. [ABSTRACT FROM AUTHOR]

The different plasma devices generating the cold atmospheric plasma jets were developed and tested. The single plasma jet with the cylindrical and planar symmetry and multijet devices are operated in helium or argon gas flow in surrounding air. The plasma jet can be up to 7 cm length and can be considerably elongated with a plastic flexible tube connected to the device. The interaction of the plasma jet with cancer calls in vitro was studied for different regimes of plasma generation. The optimization of plasma parameters was done in the experiments, in 2D fluid model simulations, and with MTT and iCELLigence assays checking the viability of cancer cells for different plasma regimes. [ABSTRACT FROM AUTHOR]

With the popularity of immunotherapy, the technology of chimeric antigen receptor (CAR) modified T cells has received widespread attention. To date, the most successful and prevalent use of CAR T cell therapy is the CAR T cells targeting CD19 in B cell malignancies, such as acute lymphoblastic leukemia (ALL) and chronic lymphoblastic leukemia (CLL), as well as B cell non-Hodgkin Lymphoma (NHL). Concerning the remarkable success, a great many clinical trials applying CAR T cell therapy to solid tumors have been carried out, but these results have shown disappointing results. Several reasons may contribute to the limited effectiveness of CAR therapy in solid tumor, such as antigens on solid cancers are often heterogenous, physical barriers constrain the infiltration of T cells, and the repeating targeting of CAR T cells may give selective pressure on tumors. In this paper, according to the screening of specific antigens, optimization of receptor structure, affinity of T cells binding tumor antigens and CAR T cells homing, the existing improvement direction and feasible optimization of CAR-T technology has been discussed. The safety considerations (correlated to toxicity) of CARs therapy, the time and money cost of CAR T cells manufacturing, the cryopreservation of CAR T cells, formulation general principles for quality assurance, if these aspects mentioned above are solved, CARs therapy in solid tumors will have great application prospects in clinical use. [ABSTRACT FROM AUTHOR]

In this paper, the effect of boosting interferon alpha (INF-α ) in immunotherapy by using mathematical modeling was analyzed. In this model, tumor growth is described as a tumor cells population with immunotherapy. This model also describes the effect of interferon alpha (INF-α ) on dynamics of tumor cells. Numerical modeling of immunotherapy with or not boosted interferon alpha (INF-α ) is presented in this paper. We obtained that boosting interferon alpha (INF-α ) in immunotherapy have a very significant role in killing of tumor cells. Interferon alpha (INF-α ) that administered in 4 pulses from day 1 to day 34 to strength 4.8 can still kill the tumor, but when it was reduced to strength 4.7 cannot kill the tumor. [ABSTRACT FROM AUTHOR]

At present, malignant tumor is still the second most fatal disease in the world. Different from conventional treatment methods of malignant tumor such as surgery, chemotherapy and radiotherapy, molecular targeted therapy, as a new method of tumor treatment, is becoming a hot spot in tumor treatment research with its advantages of high efficacy, low toxic side effects and high specificity. With the continuous development of molecular biological mechanisms and the continuous promotion and support of the biotechnology industry, the exploration of tumors has also further deepened. More and more tumor specific molecular targets have been recognized by people, followed by the development of anti-tumor small molecule targeted drugs. The thesis aims to summarize and review the tumor targets and the corresponding small molecule targeted drugs according to the different molecular biological characteristics of tumors. In the March 2011 issue of Cell, professor Douglas Hanahan and professor Robert A. Weinberg published a review: Hallmarks of Cancer: The Next Generation, which summarized the hot spots and advances in oncology in the last decade, and expanded the six features of tumor cells to ten. These ten characteristics are as follows: Self-sufficient Growth Signals, Insensitivity to Antigrowth Signals, Resisting the Cell Death, Limitless Replicative Potential, Sustained Angiogenesis, Tissue Invasion and Metastasis, Avoiding Immune Destruction, Tumor Promotion Inflammation, Deregulating Cellular Energetics, and Genome Instability and Mutation. In this thesis, we elaborate the current research progress of small molecule targeted anti-tumor drugs from the classification of ten characteristics of tumors. [ABSTRACT FROM AUTHOR]

With the novel approach of molecularly stratified therapies based on genetic characteristics of individual tumors, the need for databases providing information on molecular alterations and targeted treatment options is increasing rapidly. In Molecular Tumor Boards (MTB) professionals discuss molecular alterations and provide biological context for therapeutic options using external knowledge databases. The identification of informative databases and the information on their specific contents can greatly facilitate and standardize the functioning of a MTB. In this work we present a list of databases which have been deemed useful and relevant for MTB in a clinical setting. We describe workflows to recommend the use of specific databases at different steps in the clinical curation process. Information obtained from these databases is a necessary prerequisite to evaluate molecular alterations and devise rational targeted therapies in MTB. [ABSTRACT FROM AUTHOR]

Objective: Knowing that the most important steps related to planning systems and the success of IMRT is the optimization process, the objective of this work was to reach an optimal intensity pattern through cost functions by comparing the 3D-CRT technique and the IMRT technique for carcinomas of the head and neck and breast. The results obtained in the passage between these two techniques have shown good results for the treatment of these tumors and a great advantage in the optimization to avoid OAR. Materials and methods: To fulfill the objective proposed in this work for the head and neck plan, a SIB with a prescribed dose of 70 Gy for PTV1 and 56 Gy for PTV2 given in 35 fractions was used. In the breast plan with a prescribed dose of 50.4 Gy for PTV and 58.8 Gy for PTV boost delivered in 28 fractions. 6 MV and 10 MV photons were used for an Elekta Synergy linear accelerator, equipped with an MLC. Monaco was used as a TPS system. The Elekta iViewGT panel was used as the matrix for 2D quality control. The analysis of the data was done using the conformality index (CI) and the heterogeneity index (HI). A tolerance limit was proposed for quality control over 85% according to the hospital protocol. Results: Head and neck: The 3D technique and the 3 modulated techniques were able to meet the dose limit for PTV1 of D95% ≥ 66.5 Gy and the dose for PTV2 of D95% ≥ 53.2 Gy. The CI values for Step and Shoot and dMLC were the best for the PTV, as well as for the OARs such as the medulla and parotid. The PTV2D95 (Gy) of all techniques successfully exceeds the limit value of 53.2 Gy greatly satisfying the optimal intensity pattern using IMRT showing that the modulated techniques have better performance in these types of carcinomas. Breast: An acceptable plan with double-arch VMAT was achieved for the increase in dose coverage for 95% PTV (55.9 Gy) with 57.2 Gy. A difference of the four techniques was not significant in the spinal cord. The objective of this work is established with a significant comparison between the ordinary technique and the modulated techniques. Conclusions: the different comparisons made between the classical and the modulated techniques suggest a more significant contribution and better dose distribution and coverage in the PTV for the IMRT techniques. As observed in the present work, the main advantage of VMAT lies in the reduction of the treatment time in the two types of carcinomas. For the head and neck, it is possible to obtain a plan with the acceptable dMLC technique by increasing the number of control points and finding the best fit with the optimization properties. In the breast, IMRT had a more favorable dose distribution compared to the 3D-CRT delivery mode. It was possible to determine the optimal intensity pattern for both cases. [ABSTRACT FROM AUTHOR]

This paper presents an overview of the applications of ultrasound for the treatment of an ever-growing range of medical conditions. After presenting a brief history of the development of therapeutic ultrasound, the different mechanisms by which beneficial bio-effects are triggered will be discussed. This will be followed by a discussion of some of the more promising applications, some of which have already been licensed and introduced into the clinic. The case of liver tumour ablation will be discussed to demonstrate some of the engineering challenges that still need to be overcome before this technology finds wider uptake in the medical world. [ABSTRACT FROM AUTHOR]

The article presents the mathematical modeling of the phenomenon of artificial hyperthermia which is caused by the interaction of an electric field. The electric field is induced by the applicator positioned within the biological tissue with cancer. In addition, in order to estimate the degree of tumor destruction under the influence of high temperature an Arrhenius integral has been used. The distribution of electric potential in the domain considered is described by the Laplace system of equations, while the temperature field is described by the Pennes system of equations. These problems are coupled by source function being the additional component in the Pennes equation and resulting from the electric field action. The boundary element method is applied to solve the coupled problem connected with the heating of biological tissues. [ABSTRACT FROM AUTHOR]

Analytic review of domestic and foreign literature dedicated to X-ray endovascular studies in the therapy for malignant tumors aiming to diagnose and treat tumors showed a great interest to the agent named Lipiodol Ultra Fluid, developed by Guerbet (France) that is oil soluble radio-opaque agent meant mainly for lymphography and sialography. The interest of researchers is caused by the ability of Lipiodol to penetrate into tumor cells and stay there for a long time expressing diagnostic efficacy and in a number of cases expressing anti-tumor effect. The authors note that the mechanism of anti-tumor effect of Lipiodol is still unclear. High viscosity of Lipiodol can be considered as its shortages that at giving intravascular therapy with Lipiodol it can result in embolism of organs of vital importance. The present study was aimed to develop effective oil soluble radio-opaque agent that would not cause vessels embolism but could infiltrate neoplastic tissue while administrating it into vessels of the tumors of parenchymastous organs. [ABSTRACT FROM AUTHOR]

Obvious advantage of IORT (intraoperative radiotherapy) is that the radiation source is delivered directly to the bed of the tumor during surgery, thus avoiding the negative impact on the skin, subcutaneous tissue and reducing the risk of fibrosis. Sinonasal tumors--a convenient object for intraoperative radiotherapy application (surface location, relatively small size tumors, good operational access). The surface location and comparatively small size of neoplasms, good operational access provide an efficient and accurate transfer of the electron beam to the postoperative cavity to increase the irradiation dose in the areas of the most probable recurrence, which makes the tumors of this localization a convenient object for the use of the intraoperative radiation therapy. The treatment was conducted using a mobile compact betatron (MIB-6E), 10-12 Gy single dose. IORT session extends surgery period by 30 min. There were no pathological clinical and laboratory reactions on IORT in the early postoperative period. Carrying out the procedure is possible in various standard operating rooms. It does not require special security measures for the patients and the staff. IORT with the help of electron beam allows avoiding post-radiation reactions and achieving a 5-year--disease-free survival of 66% of the patients. IORT session is possible through a minimal incision during organ preservation surgeries. Evident economic feasibility provides the prospects of applying IORT in the clinical practice. [ABSTRACT FROM AUTHOR]

Among many methods in tumor treatment, ultrasound hyperthermia is characterized by non-invasiveness, and it has been proven very effective for clinical treatment. But the problem of monitoring temperature limits its development. MRI-based temperature mapping techniques are safe compared with invasive methods and have been applied to detect temperature changes for a variety of applications. Among these techniques, the proton resonance frequency (PRF) method is relatively advanced. With a temperature measuring experiment and experiment conducted on tumors inside rabbit legs, the effectiveness of PRF method has been proved. This paper is to introduce an MRI guided ultrasound superficial tumor hyperthermia instrument based on PRF method. [ABSTRACT FROM AUTHOR]

Sonication with fast scanning method can generate homogeneous lesions without complex planning. But when the target region is large, switching focus too fast will reduce the heat accumulation, the margin of which may not ablated. Furthermore, high blood perfusion rate will reduce this maximum volume that can be ablated. Therefore, fast scanning method may not be applied to large volume tumor. To expand the therapy scope, this study combines the fast scan method with multiple mode strategy. Through simulation and experiment, the feasibility of this new strategy is evaluated and analyzed. [ABSTRACT FROM AUTHOR]

Preferential acoustic absorption and heating of bone can significantly impact interstitial ultrasound ablation of tumors within or bordering the spine. Furthermore, intervening cortical bone may provide acoustic and thermal insulation that can protect sensitive structures nearby, such as the spinal cord. The objectives of this study are firstly, to apply parametric and patient-specific models to theoretically assess the feasibility of interstitial ultrasound ablation of tumors within and near the spine, and secondly, to identify potential energy delivery strategies, safety criteria, advantages, and disadvantages of interstitial ultrasound in this setting. Transient biothermal models using previously validated approximations for power deposition within bone from interstitial sources were employed. Multilayered axisymmetric models were used to perform a parametric assessment of the impact of tumor dimensions, attenuation (dependent on residual bone content), perfusion, and maximum temperature thresholds on necessary treatment parameters and on treatment effectiveness. 3D patient-specific finite element models were generated based on segmented CT scans for nine representative patient cases selected to bracket a range of clinical interest, with tumors in or near the vertebrae, sacrum, and ilium. Tumors were 10-27 mm in diameter, 10-43 mm long, and 0-14 mm from the spinal canal. Paraspinal tumors, osteolytic vertebral tumors, and a mixed osteolytic/osteoblastic iliac bone tumor were considered. 7 MHz (1.5 mm OD) and 3.0 MHz (3.2 mm OD) applicators with an array of 1-4 tubular transducers (0.5 -1.5 cm long, 150-360° sector angles), were applied in various implant configurations. Variable thicknesses of bone insulating critical anatomy from the tumor and insulation of the spinal cord with injected carbon dioxide were also investigated for definition of safety margins and possible protection of critical structures. 6-44 mm diameter osteolytic tumors surrounded by bone and blastic (high bone content) lesions up to 20 mm in diameter could be fully ablated by 7 MHz interstitial ultrasound using 120-5,900 J and treatment durations of 0.4-15 min. 100% of the volumes of five simulated tumors located 4.3-14 mm from the spinal canal and 94.6-99.9% of the volumes of four simulated tumors 0-4.5 mm from the spinal canal were ablated (>240 EM43°C) within 15 min without damaging (<6 EM43°C) critical nerves. Preferential ultrasound absorption and concomitant heating at bone surfaces allowed for faster, more effective ablations with less delivered energy. 3-5 mm of normal cortical bone was found to provide a safety margin and reduce temperature elevations in untargeted tissues. Critical anatomy less than 3-5 mm from a tumor encapsulated by bone could be preserved by reducing the acoustic energy aimed towards these structures and/or through injection of insulating CO2. Parametric and patient-specific studies demonstrated the feasibility of interstitial ultrasound ablation of paraspinal tumors and osteolytic tumors within the spine. Preferential absorption of ultrasound by bone may provide improved localization, faster treatment times, and larger treatment zones in highly osteolytic and soft tissue tumors in and near bone compared to other heating modalities. This work was supported by the NIH grant R44CA112852. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the clinical performance of MRgFUS in primary pain palliation of painful bone metastases and in local tumor control. Materials and Methods: We enrolled 26 consecutive patients (female/male 12/14; age: 64.7±7.5yrs) with painful bone metastases. Before and 3 months after MRgFUS treatment pain severity and pain interference scores were assessed according to Brief Pain Inventory-Quality of Life (BPI-QoL) criteria and patients underwent both CT and MRI. Local tumor control was evaluated according to lesion size, density and perfusion at CT, dynamic contrast enhancement at MRI (Discovery 750HD, GE; Gd-Bopta, Bracco) and metabolic activity at PET or scintigraphy. Patients were classified as responders or non-responders. Results: No treatment-related adverse events were recorded during the study. As statistically significant difference between baseline and follow-up values for both pain severity and pain interference scores was observed (p<0.05). Increased bone density was observed in 9/26 (34.6%) patients. Non-Perfused Volume values ranged between 20% and 92%. There was no difference in NPV values between responders and non-responders (46.7±24.2% [25 - 90 %] vs. 45±24.9% [20 - 93 %]; p=0.7). In 6 patients (5 prostate and 1 breast primary cancer) there was nearly absence of metabolic activity after treatment (mean SUV=1.2). Conclusion: MRgFUS can be safely and effectively used as the primary treatment for pain palliation in patients with painful bone metastases; moreover our experience demonstrated also a potential role for the MRgFUS in local tumor control. [ABSTRACT FROM AUTHOR]

MR-guided high-intensity focused ultrasound ablation is a promising, noninvasive method for treatment of bone tumors and palliation of pain. During thermal therapy, temperature mapping is necessary to ensure proper heat deposition in targeted tumors as well as to prevent unnecessary heating in surrounding tissues. Conventional MR thermometry exploits the proton resonant frequency shift of water protons, which normally requires a long echo time; therefore, this method is not appropriate for cortical bone due to its short T2* relaxation time. This work demonstrates that ultrashort echo-time MRI can characterize T1 changes in cortical bone caused by temperature changes. Ex vivo experiments were performed to heat diaphysis segments of bovine femurs with an interstitial ultrasound applicator. The T1 increase in the heated parts of cortical bone was observed. The temerature dependence of T1 in cortical born was also assessed by heating bovine bone samples in a temperature-controlled water bath. T1 mapping of cortical bone enabled by ultrashort echo-time MRI might allow for more accurate characterization of thermal dose during treatment of bone tumors. [ABSTRACT FROM AUTHOR]

In this project, the dose distributions of a clinical Iridium-192 (192Ir) brachytherapy source in the presence and absence of a magnetic field (3T strength) was calculated using the TOPAS Monte Carlo tool. We wanted to verify the existence of a more contained deposition of dose because of the Lorentz force induced by the external magnetic field. Based on those findings we suggest which kinds of tumors would be suited for a treatment combining brachytherapy and magnetic fields. [ABSTRACT FROM AUTHOR]

This work investigated the absorbed dose distribution in a CyberKnife VSI using a single Gafchromic EBT3 film piece per beam irradiated directly in liquid water and parallel to the radiation beams. In particular, the total scatterfactor, Ssf, correction factor kQclin,QmsrkQclinfclin,fmsr, percentage depth dose (PDD), tissue maximum ratio (TMR) and off-axis ratio (OAR) were measured. The calibration of the film was performed under reference conditions in a 6 MV X-ray beam produced by a linear accelerator Varian iX, while the measurements in the Cyberknife were carried out at 70 cm source to surface distance parallel to the beams. The results obtained with the EBT3 film are in agreement, within measurement uncertainties, with that measured with an IBA stereotactic field diode (SFD), excluding the 5 mm field diameter where 4.9% and 11% differences were observed in the Ssf values and PDD between 50 mm and 150 mm water depth, respectively. The higher discrepancy in the PDD data can be associated to a bending effect caused by the water pressure over the film's surface during the irradiation. Based on this observation, one can conclude that the use of a single film piece parallel to the radiation beams to measure PDD directly in liquid water can only apply for field sizes larger than or equal to 10 mm diameter. For smaller field sizes, perpendicular measurements must be performed. Comparing our data for kQclin,Qmsrkfclin,fmsr with that published in the literature and calculated through Monte Carlo simulation, quite good agreement is observed except for the field sizes of 7.5 mm and 5 mm in diameter where variations of 11% and 16% are obtained, respectively. This suggests that the method proposed to measure the percentage depth dose in a 10cm ? 10cm square field from a single exposure can accurately apply in small field dosimetry if measurements are performed under strict precautions. [ABSTRACT FROM AUTHOR]

Eye malignancies that are suitable candidates for low dose-rate brachytherapy have been treated using the Collaborative Ocular Melanoma Study (COMS) eye plaques with radioactive I-125 seeds at the University of Oklahoma Medical Center (OUMC). Partially loaded plaques are used to make surgical placement more convenient, especially for tumors that are posteriorly located. Over the past years, clinical cases have been performed using posterior loaded 16 mm plaques. In posterior loaded plaque cases, the prescription point is shifted off-axis towards the center of the actual seed distribution; this allows normalization of the dose to a desired depth and area of coverage. This study investigated the dosimetry of a 16 mm fully loaded eye plaque and partial loads equivalents (approximated) to 12 mm and 10 mm eye plaques with radioactive I-125, 6711 model seeds. The dose calculation agreement was assessed for two commercially used treatment plans and verified with film measurements. The standard treatment plans were calculated using the Nucletron Planning Systems (NPS) and compared with plans generated with Brachtherapy Planning 11.0.47 (Varian Medical Systems). Delivered doses were measured in water using Gafchromic EBT3 film. Doses at the prescription point as well as dose to points corresponding to critical structures were evaluated. The findings of this study reveal that calculated doses by NPS and Brachtherapy Planning are higher than measured doses for all distributions studied. Differences between NPS and Brachtherapy Planning were higher for off-axis prescription points. Differences in percent doses for low dose regions were comparable for both fully and posterior loaded plaques. [ABSTRACT FROM AUTHOR]

Treatment with doxorubicin (DOX) is a common regime in treating various types of cancer. DOX-NP™ is one of a well established marketed liposomal formulation for DOX. It offers distinct advantages over conventional DOX in reducing the cardiac toxicity and increasing the tolerability and efficacy. Gold nanoparticles (GNPs), a typical biocompatible nanomaterial, have been widely used in biomedical engineering and bioanalytical applications such as biomedical imaging and biosensors. Ehrlich tumors were grown in female balb mice by subcutaneous injection of Ehrlich ascites carcinoma cells. Mice bearing Ehrlich tumor were injected with saline, free doxorubicin (DOX) in solution, gold nanoparticles loaded liposomes and commercial liposomal encapsulated doxorubicin (DOX-NP™). The results showed that GNPs loaded liposomes could enhance the antitumor activity of commercial liposomal formulation (DOX-NP™) and displayed significantly decreased systemic toxicity compared with free DOX and commercial liposomal formulation (DOX-NP™) at the equivalent dose. So the combination of GNPs and liposomes is expected to significantly increase the likelihood of cell killing and make it a promising new approach to cancer therapy. [ABSTRACT FROM AUTHOR]

Cryosurgery is a technique to eradicate abnormal biological tissues by freezing. The objective of cryosurgery is to maximize cryoinjury of tumor tissues while at the same time minimizing cryoinjury to the surrounding healthy tissues. The location and number of cryoprobes are important factors to obtain optimal cryosurgery in complex-shaped tumors. This paper presents multiprobe cryosurgery simulation with optimal cryoprobes location in target region. Bubble packing method is used to obtain optimal cryoprobes layout. We consider mathematical model of freezing by bioheat transfer equation in solid (frozen tissue), liquid (unfrozen tissue), and mushy region. This model is referred to as Stefan problem where the location of moving solid-mushy or mushy-liquid interface is not known and it is as part of the solution. We reformulate the bioheat equations into single enthalpy (energy) equation which can resolve the moving boundary between two phases. The first-order of Godunov method is adopted to obtain numerical solution of the phase change problem. This method is easily applied since we only solve one governing equation regardless the moving interface between two phases. For demonstration purposes, multiprobe cryosurgery for lung cancer case with complex geometry is simulated and interpreted. The numerical simulation for three to ten cryoprobes configuration shows that the nine cryoprobes layout has the smallest total defect in this case. The numerical results provide an important information for cryosurgeon before conducting effective cryosurgery protocol. [ABSTRACT FROM AUTHOR]

In this work, we discussed some of the applications which X-rays and electron beam used in radiotherapy for tumor treatments. This study has been performed at Radiation Oncology Department, Medicine Faculty in Gaziosmanpasa University by using the VARIAN CLINICA DHX linear accelerator which is operated in the range of 6 MeV - 15 MeV. Processes for the treatments that X-rays used for pancreas, bladder and prostate tumors and the processes that the electron beam used for some of the derm tumors are studied. Effects of X-rays and electron beams to treatments process are examined and the obtained results are presented comparatively. [ABSTRACT FROM AUTHOR]

Image segmentation is a challenging process in order to get the accuracy of segmentation, automation and robustness especially in medical images. There exist many segmentation methods that can be implemented to medical images but not all methods are suitable. For the medical purposes, the aims of image segmentation are to study the anatomical structure, identify the region of interest, measure tissue volume to measure growth of tumor and help in treatment planning prior to radiation therapy. In this paper, we present a review method for segmentation purposes using Computed Tomography (CT) images. CT images has their own characteristics that affect the ability to visualize anatomic structures and pathologic features such as blurring of the image and visual noise. The details about the methods, the goodness and the problem incurred in the methods will be defined and explained. It is necessary to know the suitable segmentation method in order to get accurate segmentation. This paper can be a guide to researcher to choose the suitable segmentation method especially in segmenting the images from CT scan. [ABSTRACT FROM AUTHOR]

Proton beam radiation therapy (PBRT), as well as the other forms of hadrontherapy, is in use in the treatment of neoplastic diseases, to realize a high selective irradiation with maximum sparing of surrounding organs. The main characteristic of such a particles is to have an increased radiobiological effectiveness compared to conventional photons (about 10% more) and the advantage to deposit the energy in a defined space through the tissues (Bragg peak phenomenon). The goal of ELIMED Project is the realization of a laser accelerated proton beam line to prove its potential use for clinical application in the field of hadrontherapy. To date, there are several potential clinical applications of PBRT, some of which have become the treatment of choice for a specific tumour, for others it is under investigation as a therapeutic alternative to conventional X-ray radiotherapy, to increase the dose to the tumour and reduce the side effects. For almost half of cancers, an increased local tumour control is the mainstay for increased cancer curability. [ABSTRACT FROM AUTHOR]

The present study is aimed at predicting liver tumor temperature during a high-intensity focused ultrasound (HIFU) thermal ablation using the proposed acoustics-thermal-fluid coupling model. The model comprises the linear Westervelt equation and bioheat equations in liver and blood vessel. The nonlinear hemodynamic equations are also taken into account with the convected cooling and acoustic streaming effects being considered in the current HIFU simulation study. We found from this three-dimensional three-field coupling study that in large blood vessel both convective cooling and acoustic streaming can change the temperature near blood vessel. [ABSTRACT FROM AUTHOR]

The article presents novel method of combined therapy of superficial tumours based on excitation of ultrasonic waves in tumour tissues by means of ring-shaped waveguide with subsequent radiotherapy and results of its theoretical and experimental studies. Harmonic analysis of forced flexural vibration of the waveguide using ANSYS software and APDL (ANSYS Parametric Design Language) was implemented for determination of waveguide geometric parameters providing its resonance for the given excitation frequency. The developed finite element model accounts for interaction between the waveguide and tumour tissue as well as initial prestressing of tissue radially compressed by the waveguide. Resonant curves of the waveguide in terms of its thickness and diameter are calculated and presented. Experimental studies were performed in vivo on white rats with inoculated sarcoma M-1 tumours. Treatment was performed using ultrasound with frequency 22-23 kHz and intensity about 2 W/cm2. Ultrasonic treatment was proved to be an efficient modifier of radiotherapy. [ABSTRACT FROM AUTHOR]

In this paper design of Dynamic wedge system we discuss the controlling of beam shaping device namely secondary collimator, which creates varying field intensity while the radiation beam is on. Due to the motion of collimator, different segments of the treatment field will be exposed to the primary beam for different intervals of time. The amount of dose that will be delivered to the patient as the collimator moves across the treatment field is controlled by pre-calculated computer selected lookup table. It leads toward the conformal treatment and there by sparing good tissue, this increases quality of treatment. This dynamic wedge profile will be achieved by the logical and mathematical algorithm which will be implemented using Xilinx and Lab VIEW software. National semiconductors LabVIEW software is use to design GUI and obtain prerequisites for Xilinx to do mathematical calculation. [ABSTRACT FROM PUBLISHER]

Treating tumors or other potentially large targets for thermal ablation can be a very time-consuming task in ultrasound surgery. Tumors are conventionally treated by pointwise scanning over the tumor region using predetermined focal points. During scanning, cooling times are needed between two consecutive focal points to diffuse thermal buildup in the near field, which can prevent undesired temperature rises in healthy tissue. It is possible to accelerate the treatment while ensuring the safety of healthy tissue by reallocation of the heating and cooling times for individual focus points. In this study, we proposed a sub-volume heating strategy by reducing the number of cooling periods, to shorten the treatment time. The target volume is divided into several equally sized sub-volumes, each of which is covered by the same number of focal points. The sub-volume is sonicated, followed by a constant cooling period (the number of cooling periods = the number of sub-volumes). The proposed strategy was evaluated with numerical simulations in 3D and ex vivo experiments using three different: (1) a „conservative? approach, wherein each focal point is a sub-volume; (2) an „aggressive? approach, wherein all focal points make up a sub-volume; and (3) an „intermediate? approach, wherein several focus points make up a sub-volume. The results demonstrate the efficacy of this strategy; it was able to effectively reduce the treatment times by decreasing total cooling times. This study indicated that by appropriate selection of the sub-volume size and heating sequence, it may be useful to overcome the current obstacle of treatment time during large tumor treatments. [ABSTRACT FROM AUTHOR]

Image-guided technology, such as MR-guided focused ultrasound surgery, has recently proposed as a treatment for moving-tumor. However, the 3 Hz frame rate of MR imaging is still too slow for real-time tracking of the tumor in motion. The fact that a 30 Hz frame rate can easily be achieved with the ultrasound imaging system makes it a very viable option. In this study, an ultrasound imaging tracking algorithm for liver tumor has been developed. The proposed ultrasound imaging tracking algorithm utilized the concepts of pattern matching, local search, and image correlation to track a pre-specified target area in real time. In order to know the resolution of the proposed tracking algorithm, animal experiments were conducted. Three 6 degree-of-freedom electromagnetic tracking sensors, the 3D guidance trakSTAR, were surgically attached to the liver of anesthetized pigs. The liver motion could then be derived from the position signal from the trakSTAR sensors with a resolution of 0.5mm. The in-vivo experiments showed the tracking accuracy of the ultrasound-guided tracking algorithm is better than 1 mm for moving tumors. [ABSTRACT FROM AUTHOR]

Objective: To assess the long-term improvement in symptoms after magnetic resonance-guided focused ultrasound surgery (MRgFUS) for uterine myomas. Methods: Japanese women with symptomatic myomas underwent MRgFUS using the ExAblate 2000 system. The symptom severity score (SSS) was examined before and after the treatment at 3, 6, 12, 24, and 48 months. Simultaneously, we asked the patients' satisfaction level regarding the overall change of subjective symptoms: symptom free, improved a great deal, improved to some extent, no change, or worsened. The myoma volumes were measured at 6, 12, 24, 36 and 48 months after MRgFUS. Results: No severe adverse event occurred with any of the patients. The mean SSS value before treatment was 38.3 ± 21.5 (n = 106), which diminished significantly during follow-up for 3-48 months after treatment. Patients' satisfaction level was favorable, although the response rate was low. Over 80% of the patients replied that their symptoms were improved to at least some extent, and over 50% of the patients replied that their symptoms were improved a great deal. This trend continued throughout this follow up period. The mean myoma volume was also decreased from the pretreatment volume in this follow up period. Conclusion: MRgFUS is an effective and safe method for treating symptomatic uterine myomas. Long-term symptomatic improvement is promising. [ABSTRACT FROM AUTHOR]

High-intensity focused ultrasound (HIFU) treatment using ultrasound contrast microbubbles for enhancing the heating effect has been developed with the aim of realising a less invasive tumor therapy. The focused sound waves result in an increase in temperature and increased thermal absorption, which necroses tumor cells. In addition, microbubbles are used as contrast agents for ultrasound imaging, and, in a previous study, we used microbubbles to enhance the heating effect. However, when microbubbles exist in the ultrasound pathway, they disturb ultrasound propagation and distort the acoustic field. Distortion of the acoustic field leads to defocusing and causes unexpected damage to tissue in the body. The objective of the present study is to propose a method by which to destroy microbubbles in the ultrasound pathway and to focus the thermal energy only at the focal point. The proposed method consists of two steps. The first step is to use repetitive high-intensity, short-burst waves (20 waves) to destroy the microbubbles in the pathway. In the second step, low amplitude continuous waves are sent in order to heat the focal point. This method was successful for a gel containing microbubbles with a void fraction on the order of 10-4. The results of the present study indicate that more microbubbles were destroyed as the non-exposure time and the pulse number were increased during the first step. [ABSTRACT FROM AUTHOR]

Spherical transducers used for HIFU therapy produce small single lesions that are ellipsoidal in shape. The placement of these lesions side by side requires precision if an entire tumor is to be ablated reliably. This can be difficult to produce in moving organs like the liver. It has been shown that a toroidal transducer makes it possible to significantly increase the focal zone. A HIFU device has been developed using this principle to treat liver metastases during an open procedure. The toroidal transducer is composed of 256 elements. Metastases suitable for such a local therapy are typically 2cm in diameter. A typical ablation produced in vitro in 40 seconds has an average diameter of 14.1mm and an average depth of 28.5mm. Despite this progress, it remains necessary to juxtapose these single lesions to treat tumors with safety margins. The aim of this project is to use electronic beam steering in order to avoid the need to juxtapose single ablations. In vitro tests were conducted to validate new treatment parameters determined using software developed in the laboratory. It was shown that, using electronic focusing, similar treatment can be achieved in half the time (20s). The average diameter and depth of these ablations were 12.9mm and 31.1mm respectively. In addition, it was possible to double the coagulated volume while keeping the same duration of treatment. In this case the average ablated dimensions obtained in 40 seconds were 25.8mm in diameter, and 42.5mm in length. Finally, larger ablations with an average diameter and length of 40.0mm and 54.4mm respectively have been obtained in 130 seconds. In conclusion, these results indicate that the treatment of a metastasis in the liver with safety margins is conceivable using a single exposure with no need to juxtapose single lesions. [ABSTRACT FROM AUTHOR]

In HIFU treatment applications, the annular array transducer is a feasible solution for the clinical/engineering requirements which are as follows: ablation of tumors deep inside body, electronic dynamic focusing in the depth direction, simple configuration/operation, and lower cost due to fewer elements/channels of amplifier. A 12 cm-diameter, 12 cm-radius-of-curvature annular array transducer has been developed in this study. The pseudo-inverse method was adopted to calculate the desired phase of each element for focusing, and the Rayleigh-Summerfield integral was used to obtain the ultrasonic pressure field. In the simulation, the operating frequency was 0.9 MHz, and the acoustic medium was water. A piece of 1-3 piezocomposite was fabricated using the dice and fill technique for the pilot test. The dimension of the sample was 4 × 2 cm, and it was thermally shaped using a spherical mold of 12 cm in radius. The results of the simulation showed that the focus could not be moved electronically in the depth direction until the number of elements (annuli) was equal to or higher than 5, and the dynamic focusing range increased as the number of elements increased. The intensity at the acoustic window or skin was also estimated from the simulated results and was only 0.03% of the intensity at focus. The curved composite sample was tested using an impedance analyser and a radiation force balance. The resonant frequency and electro-acoustic efficiency were measured to be 0.914 MHz and 65%, respectively. The results of the simulation can provide a design guideline for the development of different-size HIFU annular array transducers. A prototype of the HIFU annular array transducer designed is being fabricated in-house. [ABSTRACT FROM AUTHOR]

As an effective and noninvasive therapeutic modality for tumor treatment, high-intensity focused ultrasound (HIFU) has attracted attention from both physicians and patients. New generations of HIFU systems with the ability to electrically steer the HIFU focus using phased array transducers have been under development. The presence of side and grating lobes may cause undesired thermal accumulation at the interface of the coupling medium (i.e. water) and skin, or in the intervening tissue. Although sparse randomly distributed piston elements could reduce the amplitude of grating lobes, there are theoretically no grating lobes with the use of concave elements in the new phased array HIFU. A new HIFU transmission strategy is proposed in this study, firing a number of but not all elements for a certain period and then changing to another group for the next firing sequence. The advantages are: 1) the asymmetric position of active elements may reduce the side lobes, and 2) each element has some resting time during the entire HIFU ablation (up to several hours for some clinical applications) so that the decreasing efficiency of the transducer due to thermal accumulation is minimized. Genetic algorithm was used for selecting randomly distributed elements in a HIFU array. Amplitudes of the first side lobes at the focal plane were used as the fitness value in the optimization. Overall, it is suggested that the proposed new strategy could reduce the side lobe and the consequent side-effects, and the genetic algorithm is effective in selecting those randomly distributed elements in a HIFU array. [ABSTRACT FROM AUTHOR]

High Intensity Focused Ultrasound (HIFU) liver tumor tracking treatments is a highly potential area of research. In order to develop a safe and effective HIFU liver tumor tracking treatment system, it is necessary to understand how tracking error affects lesion formation. In this paper, the relationship between the tracking error of the tracking mechanism and lesion formation is investigated through simulations and phantom experiments. Simulation and experimental results both show the lesion width first increases with increasing standard deviation of tracking error smaller than 1mm, then decreases with increasing standard deviation of tracking error larger than 1mm. On the other hand, the lesion length decreases with increasing standard deviation of the tracking error in all ranges. However, the lesion size still first increases with the tracking error standard deviation within 1mm, then decreases when standard deviation of tracking lager than 1mm. In another words, the lesion size is affected by the standard deviation of the tracking error as expected. Moreover, there exists an optimal lesion size around the standard deviation of 1mm in our study. By taking the standard deviation of the tracking error into consideration, this study suggests that it is possible to develop a proper treatment plan without perfect tracking of the liver tumor. [ABSTRACT FROM AUTHOR]

Magnetic fields can be used to direct magnetically susceptible nanoparticles to disease locations: to infections, blood clots, or tumors. Any single magnet always attracts (pulls) ferro- or para-magnetic particles towards it. External magnets have been used to pull therapeutics into tumors near the skin in animals and human clinical trials. Implanting magnetic materials into patients (a feasible approach in some cases) has been envisioned as a means of reaching deeper targets. Yet there are a number of clinical needs, ranging from treatments of the inner ear, to antibiotic-resistant skin infections and cardiac arrhythmias, which would benefit from an ability to magnetically 'inject', or push in, nanomedicines. We develop, analyze, and experimentally demonstrate a novel, simple, and effective arrangement of just two permanent magnets that can magnetically push particles. Such a system might treat diseases of the inner ear; diseases which intravenously injected or orally administered treatments cannot reach due to the blood-brain barrier. [ABSTRACT FROM AUTHOR]

We simulate the thermal and electrical processes, involved in the radio-frequency (RF) ablation procedure. The mathematical model consists of two parts-electrical and thermal. The energy from the applied AC voltage is determined first, by solving the Laplace equation to find the potential distribution. After that, the electric field intensity and the current density are directly calculated. Finally, the heat transfer equation is solved to determine the temperature distribution. Heat loss due to blood perfusion is also accounted for. The representation of the computational domain is based on a voxel mesh. Both partial differential equations are discretized in space via linear conforming FEM. After the space discretization, the backward Euler scheme is used for the time stepping. Large-scale linear systems arise from the FEM discretization. Moreover, they are ill-conditioned, due to the strong coefficient jumps and the complex geometry of the problem. Therefore, efficient parallel solution methods are required. The developed parallel solver is based on the preconditioned conjugate gradient (PCG) method. As a preconditioner, we use BoomerAMG-a parallel algebraic multigrid implementation from the package Hypre, developed in LLNL, Livermore. Parallel numerical tests, performed on the IBM Blue Gene/P massively parallel computer are presented. [ABSTRACT FROM AUTHOR]

A high-intensity focused ultrasound (HIFU) treatment that employs microbubbles to provide enhanced heating has been investigated in order to develop a less invasive and more rapid tumor therapy. Previous studies by the authors have demonstrated that ultrasound propagation is disturbed when microbubbles are in front of the focus. In the present study, we develop a method for obtaining enhanced heating using microbubbles just at the focus, thus avoiding heating on the transducer side. In this method, microbubbles are destroyed in front of the focal position of the HIFU (on the transducer side) by emitting a burst wave prior to the ultrasound waves used for heating the focal position. The burst wave is emitted to destroy the microbubbles. As the non-exposed time increases, the heating region moves from the transducer side to the focus because microbubbles in front of the focus are destroyed, allowing the ultrasound to effectively propagate around the target position. Using a medical ultrasound scanner, microbubble destruction and wave propagation can be visualized from the distribution of the microbubbles. Experimental results suggest that the microbubble distribution and the heating position in the developed HIFU system can be controlled. [ABSTRACT FROM AUTHOR]