Kirigami-enabled stretchable laser-induced graphene heaters for wearable thermotherapy

Flexible and stretchable heaters are increasingly recognized for their great potential in wearable thermotherapy to treat muscle spasms, joint injuries and arthritis. However, issues like lengthy processing, high fabrication cost, and toxic chemical involvement are obstacles on the way to popularize stretchable heaters for medical use. Herein, using a single-step customizable laser fabrication method, we put forward the design of cost-effective wearable laser-induced graphene (LIG) heaters with kirigami patterns, which offer multimodal stretchability and conformal fit to the skin around the human body. First, we develop the manufacturing process of the LIG heaters with three different kirigami patterns enabling reliable stretchability by out-of-plane buckling. Then, by adjusting the laser parameters, we confirm that the LIG produced by medium laser power could maintain a balance between mechanical strength and electrical conductivity. By optimizing cutting-spacing ratios through experimental measurements of stress, resistance and temperature profiles, as well as finite element analysis (FEA), we determine that a larger cutting-spacing ratio within the machining precision will lead to better mechanical, electrical and heating performance. The optimized stretchable heater in this paper could bear significant unidirectional strain over 100% or multidirectional strain over 20% without major loss in conductivity and heating performance. On-body tests and fatigue tests also proved great robustness in practical scenarios. With the advantage of safe usage, simple and customizable fabrication, easy bonding with skin, and multidirectional stretchability, the on-skin heaters are promising to substitute the traditional heating packs/wraps for thermotherapy.

Efficacy of warm compresses in preserving perineal integrity and decreasing pain during normal labor: A systematic review and meta-Analysis

The objective of the study was to assess the effect of warm compresses in preserving perineal integrity in women who delivered a single baby vaginally with cephalic presentation. We searched PubMed, Scopus, and the ISI Web of Science databases. Two researchers worked independently and conducted the study's search, selection, and extraction. We calculated the pooled risk ratio (R.R.)- for our categorical outcomes- and mean difference (M.D.)-for our continuous outcomes- using random or fixed-effect meta-analysis according to heterogenicity status. I2 test was used to detect heterogenicity. Studies were assessed for methodological quality using the Cochrane risk of bias assessment tool. Our study analyzed 13 controlled trials (n= 3947) to compare warm compresses versus not using it during vaginal delivery. The analysis revealed that warm compresses group had better outcomes regarding episiotomy, degree of perineal trauma (third and fourth degree), perineal trauma requiring suturing, and also in behavioral pain scales (severe muscle tense, being very restless, and constant grimacing) with the following R.R. and confidence intervals: (R.R.= 0.56, 95% C.I.[0.23, 1.37]), (R.R.= 0.69, 95% C.I.[0.54, 0.89], p= 0.004),( (R.R.= 0.37, 95% C.I.[0.18, 0.77], p= 0.004), and ( (R.R.= 0.42, 95% C.I.[0.23, 0.78], p= 0.006) respectively. We conclude that among primiparous women, warm compresses group showed better outcome in improving perineal comfort than a the good of women who did not receive warm compresses after delivery.

Large-Volume Hyperthermia for Safe and Cost-Effective Targeted Drug Delivery Using a Clinical Ultrasound-Guided Focused Ultrasound Device

Lyso-thermosensitive liposomes (LTSLs) are specifically designed to release chemotherapy agents under conditions of mild hyperthermia. Preclinical studies have indicated that magnetic resonance (MR)-guided focused ultrasound (FUS) systems can generate well-controlled volumetric hyperthermia using real-time thermometry. However, high-throughput clinical translation of these approaches for drug delivery is challenging, not least because of the significant cost overhead of MR guidance and the much larger volumes that need to be heated clinically. Using an ultrasound-guided extracorporeal clinical FUS device (Chongqing HAIFU, JC200) with thermistors in a non-perfused ex vivo bovine liver tissue model with ribs, we present an optimised strategy for rapidly inducing (5-15 min) and sustaining (>30 min) mild hyperthermia (ΔT <+4°C) in large tissue volumes (≤92 cm³). We describe successful clinical translation in a first-in-human clinical trial of targeted drug delivery of LTSLs (TARDOX: a phase I study to investigate drug release from thermosensitive liposomes in liver tumours), in which targeted tumour hyperthermia resulted in localised chemo-ablation. The heating strategy is potentially applicable to other indications and ultrasound-guided FUS devices.

Magnetic nanowires in biomedical applications

Magnetic nanostructures and nanomaterials play essential roles in modern bio medicine and technology. Proper surface functionalization of nanoparticles (NPs) allows the selective bonding thus application of magnetic forces to a vast range of cellular structures and biomolecules. However, the spherical geometry of NPs poises a series of limitations in various potential applications. Mostly, typical spherical core shell structure consists of magnetic and non-magnetic layers have little tunability in terms of magnetic responses, and their single surface functionality also limits chemical activity and selectivity. In comparison to spherical NPs, nanowires (NWs) possess more degrees of freedom in achieving magnetic and surface chemical tenability. In addition to adjustment of magnetic anisotropy and inter-layer interactions, another important feature of NWs is their ability to combine different components along their length, which can result in diverse bio-magnetic applications. Magnetic NWs have become the candidate material for biomedical applications owing to their high magnetization, cheapness and cost effective synthesis. With large magnetic moment, anisotropy, biocompatibility and low toxicity, magnetic NWs have been recently used in living cell manipulation, magnetic cell separation and magnetic hyperthermia. In this review, the basic concepts of magnetic characteristics of nanoscale objects and the influences of aspect ratio, composition and diameter on magnetic properties of NWs are addressed. Some underpinning physical principles of magnetic hyperthermia (MH), magnetic resonance imaging (MRI) and magnetic separation (MS) have been discussed. Finally, recent studies on magnetic NWs for the applications in MH, MRI and MS were discussed in detail.

Delivery of Arsenic Trioxide by Multifunction Nanoparticles To Improve the Treatment of Hepatocellular Carcinoma

Arsenic trioxide (ATO) is effective in the treatment of hematological malignancies and solid tumors. However, its toxicity and side effects are severe, posing an obstacle in its clinical application. A controlled-release ATO carrier with mitochondrial targeting was constructed in this study. The safety and efficacy in vitro were investigated using a hemolysis test, cytotoxicity, proliferation, migration, apoptosis, and other changes in cell behavior. The safety and efficacy were further evaluated in vivo by hematoxylin-eosin staining, terminal deoxyribonucleotide transferase-mediated dUTP nick end labeling staining, and blood testing in tumor-bearing mice. Immunohistochemically and western blotting experiments were conducted to explore the mechanism of combination therapy of material-based chemotherapy and microwave hyperthermia in vitro. We demonstrated that the nano-zirconia (ZrO₂) loading platform may be used to administer the ATO, with local precision-controlled release and mitochondrial targeting. Furthermore, we showed the safety of this approach for delivering high doses of ATO. In addition, we explored this new method in combination with in vitro microwave heat therapy, providing a potentially novel intravenous approach to chemotherapy. We described a new non-invasive treatment that improved the efficacy of ATO chemotherapy against hepatocellular carcinoma through nano-ZrO₂ carriers.

An in vivo coil setup for AC magnetic field-mediated magnetic nanoparticle heating experiments

In vitro and in vivo evaluation of magnetic nanoparticles in relation to magnetic fluid hyperthermia (MFH) treatment is an on-going quest. This current paper demonstrates the design, fabrication, and evaluation of an in vivo coil setup for real-time, whole body thermal imaging. Numerical calculations estimating the flux densities, and in silico analysis suggest that the proposed in vivo coil setup could be used for real-time thermal imaging during MFH experiments (within the limitations due to issues of penetration depth). Such in silico evaluations provide insights into the design of suitable AMF applicators for AC magnetic field-mediated in vivo MNP heating as demonstrated in this study.

Measurements of Specific Heat Capacities Required to Build Computer Simulation Models for Laser Thermotherapy of Brain Lesions

OBJECTIVE

Laser interstitial thermotherapy has widely available. The current treatment, however, often relies on the experience of the treatment provider. To improve the accuracy of the laser treatment system in the future, it is necessary to construct simulation systems with physical properties such as heat conduction as a reference. However, no studies to measure a thermophysical property, of brain tumors have yet been conducted. Therefore, the present study was performed to measure specific heat capacities.

MATERIALS AND METHODS

The specific heat capacities of tissues obtained from two willed bodies and eight specimens of brain tumors were measured by differential scanning calorimetry.

RESULT

In normal brain tissues, changes of specific heat capacity were minimal as the tissue was heated from 37°C to 61°C. Conversely, in brain tumor tissues, changes of specific heat capacity between 37°C and 43°C were substantial, and the difference in the rate of change of specific heat capacity between brain tumor tissues and normal brain tissues was significant.

CONCLUSIONS

The specific heat measurements of brain tissues and brain tumor tissues showed that changes of specific heat capacity between 37°C and 43°C were greater in brain tumor than in normal brain tissues.

Near-Infrared Light-Harvesting Fullerene-Based Nanoparticles for Promoted Synergetic Tumor Phototheranostics

A synergetic phototheranostic system, combining diagnostic photo-imaging and phototherapies [such as photothermal therapy and photodynamic therapy (PDT)], shows great potential in today's tumor precise therapy. Herein, we fabricate near-infrared (NIR) light-harvesting fullerene-based nanoparticles (DAF NPs) for photoacoustic (PA) imaging-guided synergetic tumor photothermal and PDT. The fullerene derivatives (DAF) absorbing in the NIR region have been synthesized by conjugating NIR-absorbing antenna with fullerene. In addition, DAF NPs with good biocompatibility have been fabricated via a nanoprecipitation approach. The as-prepared DAF NPs can accumulate and generate PA signals around the tumor site 6 h post injection via enhanced permeability and retention effect in vivo. More importantly, the DAF NPs exhibit better reactive oxygen species and heat generation efficacy compared with fullerene and antenna nanoparticles (DA NPs), respectively. Further in vitro and in vivo studies demonstrate that DAF NPs can effectively inhibit tumor growth through synergetic photodynamic and photothermal therapies, which provides a new sight of photosensitizer design for enhanced cancer phototheranostics.

Biomimetic Carriers Based on Giant Membrane Vesicles for Targeted Drug Delivery and Photodynamic/Photothermal Synergistic Therapy

Membrane vesicles derived from live cells show great potential in biological applications due to their preserved cell membrane properties. Here, we demonstrate that cell-derived giant membrane vesicles can be used as vectors to deliver multiple therapeutic drugs and carry out combinational phototherapy for targeted cancer treatment. We show that therapeutic drugs can be efficiently encapsulated into giant membrane vesicles and delivered to target cells by membrane fusion, resulting in synergistic photodynamic/photothermal therapy under light irradiation. This study highlights biomimetic giant membrane vesicles for drug delivery with potential biomedical application in cancer therapeutics.

Iron-Based Core-Shell Nanowires for Combinatorial Drug Delivery and Photothermal and Magnetic Therapy

Combining different therapies into a single nanomaterial platform is a promising approach for achieving more efficient, less invasive, and personalized treatments. Here, we report on the development of such a platform by utilizing nanowires with an iron core and iron oxide shell as drug carriers and exploiting their optical and magnetic properties. The iron core has a large magnetization, which provides the foundation for low-power magnetic manipulation and magnetomechanical treatment. The iron oxide shell enables functionalization with doxorubicin through a pH-sensitive linker, providing selective intracellular drug delivery. Combined, the core-shell nanostructure features an enhanced light-matter interaction in the near-infrared region, resulting in a high photothermal conversion efficiency of >80% for effective photothermal treatment. Applied to cancer cells, the collective effect of the three modalities results in an extremely efficient treatment with nearly complete cell death (∼90%). In combination with the possibility of guidance and detection, this platform provides powerful tools for the development of advanced treatments.

Composite spheres made of bioengineered spider silk and iron oxide nanoparticles for theranostics applications

Bioengineered spider silk is a biomaterial that has exquisite mechanical properties, biocompatibility, and biodegradability. Iron oxide nanoparticles can be applied for the detection and analysis of biomolecules, target drug delivery, as MRI contrast agents and as therapeutic agents for hyperthermia-based cancer treatments. In this study, we investigated three bioengineered silks, MS1, MS2 and EMS2, and their potential to form a composite material with magnetic iron oxide nanoparticles (IONPs). The presence of IONPs did not impede the self-assembly properties of MS1, MS2, and EMS2 silks, and spheres formed. The EMS2 spheres had the highest content of IONPs, and the presence of magnetite IONPs in these carriers was confirmed by several methods such as SEM, EDXS, SQUID, MIP-OES and zeta potential measurement. The interaction of EMS2 and IONPs did not modify the superparamagnetic properties of the IONPs, but it influenced the secondary structure of the spheres. The composite particles exhibited a more than two-fold higher loading efficiency for doxorubicin than the plain EMS2 spheres. For both the EMS2 and EMS2/IONP spheres, the drug revealed a pH-dependent release profile with advantageous kinetics for carriers made of the composite material. The composite spheres can be potentially applied for a combined cancer treatment via hyperthermia and drug delivery.

A versatile induction heating system for magnetic hyperthermia studies under different experimental conditions

In recent decades, magnetic hyperthermia using magnetic nanoparticles, a promising but quite challenging method, has proven to be an effective cancer therapy procedure. In hyperthermia, heat, which is generated by magnetic nanoparticles exposed to a radiofrequency magnetic field, is employed to battle cancerous cells. Ideally, devices for magnetic hyperthermia should provide a variety of field amplitudes and frequencies for generating an appropriate and powerful alternating magnetic field. Here, we report the design and evaluation of a versatile system which provides different experimental setup possibilities for magnetic hyperthermia. The proposed system is a derivative of the Mazzilli inverter, which directly follows the resonant frequency of the LC tank circuit independent of its component. The feasibility of the system for hyperthermia studies was examined using iron oxide nanoparticles prepared by the coprecipitation method. Different experimental conditions including nanoparticles in solution and dispersed in gelatin phantoms were evaluated. Four different coils including two solenoids, a pancake, and a Helmholtz-like format were successfully tested. Using these coils, 18 different operation frequencies in the frequency band of 63-530 kHz with field strengths up to 27.2 kA/m were achieved.

Four-dimensional optoacoustic monitoring of tissue heating with medium intensity focused ultrasound

Medium-intensity focused ultrasound (MIFU) concerns therapeutic ultrasound interventions aimed at stimulating physiological mechanisms to reinforce healing responses without reaching temperatures that can cause permanent tissue damage. The therapeutic outcome is strongly affected by the temperature distribution in the treated region and its accurate monitoring represents an unmet clinical need. In this work, we investigate on the capacities of four-dimensional optoacoustic tomography to monitor tissue heating with MIFU. Calibration experiments in a tissue-mimicking phantom have confirmed that the optoacoustically-estimated temperature variations accurately match the simultaneously acquired thermocouple readings. The performance of the suggested approach in real tissues was further shown with bovine muscle samples. Volumetric temperature maps were rendered in real time, allowing for dynamic monitoring of the ultrasound focal region, estimation of the peak temperature and the size of the heat-affected volume.

Facile syntheses of conjugated polymers for photothermal tumour therapy

Development of photothermal materials which are able to harness sunlight and convert it to thermal energy seems attractive. Besides carbon-based nanomaterials, conjugated polymers are emerging promising photothermal materials but their facile syntheses remain challenging. In this work, by modification of a CBT-Cys click condensation reaction and rational design of the starting materials, we facilely synthesize conjugated polymers poly-2-phenyl-benzobisthiazole (PPBBT) and its dihexyl derivative with good photothermal properties. Under the irradiation of either sunlight-mimicking Xe light or near-infrared laser, we verify that PPBBT has comparable photothermal heating-up speed to that of star material single-wall carbon nanotube. Moreover, PPBBT is used to fabricate water-soluble NPPPBBT nanoparticles which maintain excellent photothermal properties in vitro and photothermal therapy effect on the tumours exposed to laser irradiation. We envision that our synthetic method provides a facile approach to fabricate conjugated polymers for more promising applications in biomedicine or photovoltaics in the near future.

Biomaterial scaffolds for non-invasive focal hyperthermia as a potential tool to ablate metastatic cancer cells

Currently, there are very few therapeutic options for treatment of metastatic disease, as it often remains undetected until the burden of disease is too high. Microporous poly(ε-caprolactone) biomaterials have been shown to attract metastasizing breast cancer cells in vivo early in tumor progression. In order to enhance the therapeutic potential of these scaffolds, they were modified such that infiltrating cells could be eliminated with non-invasive focal hyperthermia. Metal disks were incorporated into poly(ε-caprolactone) scaffolds to generate heat through electromagnetic induction by an oscillating magnetic field within a radiofrequency coil. Heat generation was modulated by varying the size of the metal disk, the strength of the magnetic field (at a fixed frequency), or the type of metal. When implanted subcutaneously in mice, the modified scaffolds were biocompatible and became properly integrated with the host tissue. Optimal parameters for in vivo heating were identified through a combination of computational modeling and ex vivo characterization to both predict and verify heat transfer dynamics and cell death kinetics during inductive heating. In vivo inductive heating of implanted, tissue-laden composite scaffolds led to tissue necrosis as seen by histological analysis. The ability to thermally ablate captured cells non-invasively using biomaterial scaffolds has the potential to extend the application of focal thermal therapies to disseminated cancers.

Abrupt hemodynamic changes accompanying intrapleural hyperthermic chemotherapy: Case series

RATIONALE

Intrapleural hyperthermic chemotherapy (IPHC) is the preferred method to locally treat lung cancer with pleural seeding. Anesthetic management during IPHC is a very challenging task for the anesthesiologist because of the hemodynamic instability associated with the procedure; however, there is no report on anesthetic considerations during the IPHC procedure.

PATIENT CONCERNS

Three patients who diagnosed lung cancer with pleural invasion scheduled for IPHC were reported in this case series.

DIAGNOSIS

Case 1, a 48-year-old woman, suffered from lung cancer (adenocarcinoma, T2NxM1a) with diffuse pleural seeding. Case 2, a 58-year-old female, diagnosed with lung cancer (adenocarcinoma, T3N0M1a) with pleural dissemination. Case 3, a 47-year-old male, diagnosed as sarcoma on the left lung with right pericardial invasion and right hemidiaphragm invasion (stage, T3N0M1a).

INTERVENTION

All three patients underwent IPHC with cisplatin diluted in normal saline (2000 ml) at a rate of 600 ml/min. Inflow temperature of 42°C was using a heart-lung machine over 90 minutes. Hemodynamic changes were monitored through the procedure.

OUTCOMES

The patient did not require supplemental oxygenation anymore after he recovered from lung transplantation.

LESSONS

There was sudden drop in the cardiac output and an increase in the pulmonary vascular resistance, which were caused by the volume and temperature of the hyperthermic chemotherapeutic drugs in the pleura during the early stage of IPHC; these changes can be a major problem during the procedure, and supportive hemodynamic management may be needed.

Recent advances in functional nanostructures as cancer photothermal therapy

Being a non-invasive and relatively safe technique, photothermal therapy has attracted a lot of interest in the cancer treatment field. Recently, nanostructure technology has entered the forefront of cancer therapy owing to its ability to absorb near-infrared radiation as well as efficient light to heat conversion. In this study, key nanostructures for cancer therapy including gold nanoparticles, magnetite iron oxide nanoparticles, organic nanomaterials, and novel two-dimensional nanoagents such as MXenes are discussed. Furthermore, we briefly discuss the characteristics of the nanostructures of these photothermal nanomaterial agents, while focusing on how nanostructures hold potential as cancer therapies. Finally, this review offers promising insight into new cancer therapy approaches, particularly in vivo and in vitro cancer treatments.

The Cost of Hypertermia: Nine Years Experience at the Radiation Therapy Department of the Turin University

Background

In this paper the authors try to quantify the expenditure for the equipment, staff, treatment per patient and research, sustained at the Radiation Therapy Department of the University of Turin for the treatment of cancer with hyperthermia

Methods

Two hyperthermic computerized devices are available: the SAPIC SV03 multifrequencies system (915, 434 and 2-30 MHz) for external hyperthermia, and the SACEM system. working only with the frequency of 915 MHz, for interstitial and intracavitary heating. From September 1983 to December 1991, 408 patients have been treated with hyperthermia, for a total number of treated sites of 483; 2960 heating sessions were performed, with a average of six sessions per patient.

Results

The overall cost of our “hyperthermia project” was about 2,000,000,000 Italian liras; the equipment cost was estimated at 1,258,650,000 Liras (839,100 US$), and the cost per treatment and per heat session at about 3,985,200 (2676 US$) and 664,200 liras (443 US$), respectively. The cost of the research program can be estimated in 175,000,000 liras (116,666 US$). The National Health System provides for a partial reimbursement of 2,000,000 liras (1,333 US$) for each course of hyperthermia. Taking into account the mean expected life expectancy and increasing purchases for replacement of equipment, these costs increase 10% each year. As regards the cost-benefit problem, using the Rees formula it varies from 1112 US$ when hyperthermia is used as elective treatment to 3380 US$ when hyperthermia is used as palliative treatment.

Conclusions

Hyperthermia is, in our experience, an expensive therapy.

Occupational exposure to electromagnetic fields from medical sources

High exposures to electromagnetic fields (EMF) can occur near certain medical devices in the hospital environment. A systematic assessment of medical occupational EMF exposure could help to clarify where more attention to occupational safety may be needed. This paper seeks to identify sources of high exposure for hospital workers and compare the published exposure data to occupational limits in the European Union. A systematic search for peer-reviewed publications was conducted via PubMed and Scopus databases. Relevant grey literature was collected via a web search. For each publication, the highest measured magnetic flux density or internal electric field strength per device and main frequency component was extracted. For low frequency fields, high action levels may be exceeded for magnetic stimulation, MRI gradient fields and movement in MRI static fields. For radiofrequency fields, the action levels may be exceeded near devices for diathermy, electrosurgery and hyperthermia and in the radiofrequency field inside MRI scanners. The exposure limit values for internal electric field may be exceeded for MRI and magnetic stimulation. For MRI and magnetic stimulation, practical measures can limit worker exposure. For diathermy, electrosurgery and hyperthermia, additional calculations are necessary to determine if SAR limits may be exceeded in some scenarios.

Dielectric Properties of Ex Vivo Porcine Liver Tissue Characterized at Frequencies Between 5 and 500 kHz When Heated at Different Rates

OBJECTIVE

The released energy during radio frequency thermal ablation therapy changes the dielectric properties of biological tissues. Understanding changes of dielectric properties of biological tissues during heating is fundamental to suitably model the medical procedure. The aim of this work is to obtain the thermal dependences of conductivity and permittivity of ex vivo porcine liver tissue at six frequencies from 5 to 500 kHz, during heating from 37 °C to 100 °C at three heating rates of approximately 0.1, 3, and 10 °C/min.

METHODS

Two experimental setups using different heating sources and a four-needle electrode connected to an impedance analyzer were developed to evaluate the thermal dependencies.

RESULTS

The results at a body temperature of 37 °C show a good agreement with the data reported in the literature. The conductivity initially shows an increase followed by a decrease, whereas the permittivity increases before a subsequent sharp decrease. Above 60 °C, different trends are observed for the three heating rates studied.

CONCLUSION

The electric conductivity and permittivity show a similar behavior at all evaluated frequencies and heating rates. The observed abrupt change of the slope near 45 °C at a slow heating rate may be used to identify the region of reversible changes in the tissue.

SIGNIFICANCE

These results confirm the connection among tissue dielectric properties, working frequency, and exposure time with thermal damage during heating.

Magnetic Vortices as Efficient Nano Heaters in Magnetic Nanoparticle Hyperthermia

Magnetic vortices existing in soft magnetic nanoparticles with sizes larger than the single-domain diameter can be efficient nano-heaters in biomedical applications. Using micromagnetic numerical simulation we prove that in the optimal range of particle diameters the magnetization reversal of the vortices in spherical iron and magnetite nanoparticles is possible for moderate amplitudes of external alternating magnetic field, H0 < 100 Oe. In contrast to the case of superparamagnetic nanoparticles, for the vortex configuration the hysteresis loop area increases as a function of frequency. Therefore, high values of the specific absorption rate, on the order of 1000 W/g, can be obtained at frequencies f = 0.5-1.0 MHz. Because the diameter D of a non single-domain particle is several times larger than the diameter d of a superparamagnetic particle, the volume of heat generation for the vortex turns out to be (D/d)3 times larger. This shows the advantage of vortex configurations for heat generation in alternating magnetic field in biomedical applications.

Iron oxide nanoparticles - In vivo/in vitro biomedical applications and in silico studies

The review presents a broad overview of the biomedical applications of surface functionalized iron oxide nanoparticles (IONPs) as magnetic resonance imaging (MRI) agents for sensitive and precise diagnosis tool and synergistic combination with other imaging modalities. Then, the recent progress in therapeutic applications, such as hyperthermia is discussed and the available toxicity data of magnetic nanoparticles concerning in vitro and in vivo biomedical applications are addressed. This review also presents the available computer models using molecular dynamics (MD), Monte Carlo (MC) and density functional theory (DFT), as a basis for a complete understanding of the behaviour and morphology of functionalized IONPs, for improving NPs surface design and expanding the potential applications in nanomedicine.

New experimental model for single liver lobe hyperthermia in small animals using non-directional microwaves

PURPOSE

Our aim was to develop a new experimental model for in vivo hyperthermia using non-directional microwaves, applicable to small experimental animals. We present an affordable approach for targeted microwave heat delivery to an isolated liver lobe in rat, which allows rapid, precise and stable tissue temperature control.

MATERIALS AND METHODS

A new experimental model is proposed. We used a commercial available magnetron generating 2450 MHz, with 4.4V and 14A in the filament and 4500V anodic voltage. Modifications were required in order to adjust tissue heating such as to prevent overheating and to allow for fine adjustments according to real-time target temperature. The heating is controlled using a virtual instrument application implemented in LabView® and responds to 0.1° C variations in the target. Ten healthy adult male Wistar rats, weighing 250-270 g were used in this study. The middle liver lobe was the target for controlled heating, while the rest of the living animal was protected.

RESULTS

In vivo microwave delivery using our experimental setting is safe for the animals. Target tissue temperature rises from 30°C to 40°C with 3.375°C / second (R2 = 0.9551), while the increment is lower it the next two intervals (40-42°C and 42-44°C) with 0.291°C/ s (R2 = 0.9337) and 0.136°C/ s (R2 = 0.7894) respectively, when testing in sequences. After reaching the desired temperature, controlled microwave delivery insures a very stable temperature during the experiments.

CONCLUSIONS

We have developed an inexpensive and easy to manufacture system for targeted hyperthermia using non-directional microwave radiation. This system allows for fine and stable temperature adjustments within the target tissue and is ideal for experimental models testing below or above threshold hyperthermia.

A new mild hyperthermia device to treat vascular involvement in cancer surgery

Surgical margin status in cancer surgery represents an important oncologic parameter affecting overall prognosis. The risk of disease recurrence is minimized and survival often prolonged if margin-negative resection can be accomplished during cancer surgery. Unfortunately, negative margins are not always surgically achievable due to tumor invasion into adjacent tissues or involvement of critical vasculature. Herein, we present a novel intra-operative device created to facilitate a uniform and mild heating profile to cause hyperthermic destruction of vessel-encasing tumors while safeguarding the encased vessel. We use pancreatic ductal adenocarcinoma as an in vitro and an in vivo cancer model for these studies as it is a representative model of a tumor that commonly involves major mesenteric vessels. In vitro data suggests that mild hyperthermia (41-46 °C for ten minutes) is an optimal thermal dose to induce high levels of cancer cell death, alter cancer cell's proteomic profiles and eliminate cancer stem cells while preserving non-malignant cells. In vivo and in silico data supports the well-known phenomena of a vascular heat sink effect that causes high temperature differentials through tissues undergoing hyperthermia, however temperatures can be predicted and used as a tool for the surgeon to adjust thermal doses delivered for various tumor margins.

Use of thermobalancing therapy in ageing male with benign prostatic hyperplasia with a focus on etiology and pathophysiology

INTRODUCTION

We investigated if "thermobalancing" therapy (TT), using Dr Allen's therapeutic device (DATD) in men with benign prostatic hyperplasia (BPH), can aid in understanding the etiology and pathophysiology of BPH.

METHODS

We compared urinary and other parameters of BPH patients who received TT over 6 months (treatment group) with those of healthy volunteers who had not received the treatment (control group). Dynamics of symptoms and indicators in each group were evaluated in comparison with their data at the beginning and end of the study. Parameters were the International Prostate Symptom Score (IPSS) for urinary symptoms and quality of life (QoL), ultrasound measurement of prostate volume (PV) and uroflowmetry (maximum flow rate, Q_max). TT effectiveness was examined in 124 men with BPH and PV <60 mL. We also investigated the data of five patients with BPH and PV >60 mL.

RESULTS

TT decreased urinary symptoms and PV, increased Q_max and improved QoL in men with BPH, PV <60 mL, and in men with BPH, PV >60 mL.

CONCLUSIONS

The present study demonstrated that TT is effective for BPH, suggesting that blood circulation plays a crucial role in its cause. The continuous heat exposure that does not exceed the normal body temperature terminates the trigger of BPH development, "micro-focus" of hypothermia, and the following spontaneous expansion of capillaries. TT could be considered to be a useful tool in BPH treatment.

Radio frequency-mediated local thermotherapy for destruction of pancreatic tumors using Ni-Au core-shell nanowires

We present a novel method of radio frequency (RF)-mediated thermotherapy in tumors by remotely heating nickel (Ni)-gold (Au) core-shell nanowires (CSNWs). Ectopic pancreatic tumors were developed in nude mice to evaluate the thermotherapeutic effects on tumor progression. Tumor ablation was produced by RF-mediated thermotherapy via activation of the paramagnetic properties of the Ni-Au CSNWs. Histopathology demonstrated that heat generated by RF irradiation caused significant cellular death with pyknotic nuclei and nuclear fragmentation dispersed throughout the tumors. These preliminary results suggest that thermotherapy ablation induced via RF activation of nanowires provides a potential alternative therapy for cancer treatment.

Research: Testing of a Novel Portable Body Temperature Conditioner Using a Thermal Manikin

A battery-operated active cooling/heating device was developed to maintain thermoregulation of trauma victims in austere environments while awaiting evacuation to a hospital for further treatment. The use of a thermal manikin was adopted for this study in order to simulate load testing and evaluate the performance of this novel portable active cooling/heating device for both continuous (external power source) and battery power. The performance of the portable body temperature conditioner (PBTC) was evaluated through cooling/heating fraction tests to analyze the heat transfer between a thermal manikin and circulating water blanket to show consistent performance while operating under battery power. For the cooling/heating fraction tests, the ambient temperature was set to 15°C ± 1°C (heating) and 30°C ± 1°C (cooling). The PBTC water temperature was set to 37°C for the heating mode tests and 15°C for the cooling mode tests. The results showed consistent performance of the PBTC in terms of cooling/heating capacity while operating under both continuous and battery power. The PBTC functioned as intended and shows promise as a portable warming/cooling device for operation in the field.

Use of an Intravascular Warming Catheter during Off-Pump Coronary Artery Bypass Surgery in a Patient with Severe Cold Hemagglutinin Disease

Cold hemagglutinin disease with broad thermal amplitude and high titers presents challenges in treating cardiac-surgery patients. Careful planning is needed to prevent the activation of cold agglutinins and the agglutination of red blood cells as the patient's temperature drops during surgery. We describe our approach to mitigating cold agglutinin formation in a 77-year-old man with severe cold hemagglutinin disease who underwent off-pump coronary artery bypass surgery without the use of preoperative plasmapheresis. This experience shows that the use of an intravascular warming catheter can maintain normothermia and prevent the activation and subsequent formation of cold agglutinins. To our knowledge, this is the first reported use of this technique in a patient with cold hemagglutinin disease. The chief feature in this approach is the use of optimal thermal maintenance-rather than the more usual decrease in cold-agglutinin content by means of therapeutic plasma exchange.

Medical Devices; Neurological Devices; Classification of the Thermal System for Insomnia. Final order

The Food and Drug Administration (FDA) is classifying the thermal system for insomnia into class II (special controls). The special controls that will apply to the device are identified in this order and will be part of the codified language for the thermal system for insomnia's classification. The Agency is classifying the device into class II (special controls) in order to provide a reasonable assurance of safety and effectiveness of the device.

A New Coaxial TEM Radiofrequency/Microwave Applicator for Non-Invasive Deep-Body Hyperthermia

At the moment great efforts are being made to develop non-invasive heating systems which produce controlled local or regional deep-body hyperthermia. Electromagnetic interference techniques (10-80 MHz) with several separated applicators or with multiple applicators can produce deep-body heating. In our institute a coaxial frequency-independent TEM radiofrequency/microwave applicator has been designed. This applicator can produce a theoretically optimal interference maximum in the centre of the body. The applicator is very simple to construct and inexpensive. To test the design with the equipment available, a scaled prototype of the TEM applicator has been developed. The prototype has a diameter of 20 cm and operates at 434 MHz. The applicator has been tested on several phantom materials. The measured absorbed power distributions are in good agreement with the calculated theoretical distributions. The theoretical calculations of the absorbed power distributions of a 10-80 MHz TEM deep-body applicator are very encouraging.

A New Inductive Applicator for Hyperthermia

We have designed a new type of applicator for inductive heating which consists of a one-turn, square, column-like coil, through which RF current flows. The material to be heated is placed alongside one of the external sides of the coil. The depth of penetration from an applicator with a height of 20 cm, width of 20 cm, depth of 60 cm was calculated to be 11.7 cm. However, in experiments using a muscle-equivalent agar phantom 60 cm X 60 cm X 60 cm, the penetration depth proved to be 9.6 cm; but in another experiment using a smaller phantom 20 cm X 40 cm X 60 cm, the penetration depth was 6.3 cm. This means that the depth of penetration depends not only on the size of the applicator but also on the shape of the material heated. Our study clearly showed that this applicator produces much less heat in the fat layer than in the muscle layer and should be an inductive applicator suitable for deep heating cancer therapy.

Near-Infrared Light-Activatable Microneedle System for Treating Superficial Tumors by Combination of Chemotherapy and Photothermal Therapy

Because of the aggressive and recurrent nature of cancers, repeated and multimodal treatments are often necessary. Traditional cancer therapies have a risk of serious toxicity and side effects. Hence, it is crucial to develop an alternative treatment modality that is minimally invasive, effectively treats cancers with low toxicity, and can be repeated as required. We developed a light-activatable microneedle (MN) system that can repeatedly and simultaneously provide photothermal therapy and chemotherapy to superficial tumors and exert synergistic anticancer effects. This system consists of embeddable polycaprolactone MNs containing a photosensitive nanomaterial (lanthanum hexaboride) and an anticancer drug (doxorubicin; DOX), and a dissolvable poly(vinyl alcohol)/polyvinylpyrrolidone supporting array patch. Because of this supporting array, the MNs can be completely inserted into the skin and embedded within the target tissue for locoregional cancer treatment. When exposed to near-infrared light, the embedded MN array uniformly heats the target tissue to induce a large thermal ablation area and then melts at 50 °C to release DOX in a broad area, thus destroying tumors. This light-activated heating and releasing behavior can be precisely controlled and switched on and off on demand for several cycles. We demonstrated that the MN-mediated synergistic therapy completely eradicated 4T1 tumors within 1 week after a single application of the MN and three cycles of laser treatment. No tumor recurrence and no significant body weight loss of mice were observed. Thus, the developed light-activatable MN with a unique embeddable feature offers an effective, user-friendly, and low-toxicity option for patients requiring long-term and multiple cancer treatments.

[Automated contact radiation therapy - conditions for effective use in practical healthcare]

There are discussed the following questions: the use of import-substituting technologies in sphere of contact radiation therapy based on integration of the technological complex AGAT-VT with endostatic equipment and production meth- ods of individual application systems; the use of computed tomography and magnetic resonance tomography technologies for endostatic visualizations and dosimetry; ways of laser modification and prevention of complications and apparatus- technological possibilities of direct dosimetry.

Modified MgFe2O4 Ferrimagnetic Nanoparticles to Improve Magnetic and AC Magnetically-Induced Heating Characteristics for Hyperthermia

A ferrimagnetic nanoparticle with a smaller size, a narrower size distribution, and a higher ac heat generation ability has been still studied for intra-arterial or intra-tumoral hyperthermia. In this study, we manipulate the calcining temperature in the range of 400-600 degrees C to modify MgFe2O4 ferrimagnetic nanoparticles (FMNPs) during modified sol-gel process. The modified MgFe2O4 FMNPs have well controlled with small size and narrow size distribution, so that their magnetic and ac magnetically-induced heating characteristics are significantly improved. In particular, MgFe2O4 nanoparticles synthesized at the calcining temperature of 600 degrees C and sintering temperature of 700 degrees C show the most suitable size (58 nm ± 13 nm) and its distribution (22%) resulting in the highest ac magnetically-induced heating temperature (T(AC,mag), ΔT = 93 degrees C) and SLP (Specific Loss Power, 600 W/g) at the biologically tolerable range of magnetic field (H(appl) = 140 Oe) and frequency (f(appl) = 110 kHz). It is found to be due to the improvement of magnetic softness and saturation magnetization resulting in the largest hysteresis loss power. All the results in this work clearly demonstrate that calcining process is one of the key parameters to control the proper size and size distribution for improving magnetic and ac magnetically-induced heating characteristics of MgFe2O4 FMNPs, which can be applicable to hyperthermia agents in nanomedicine.

Benign Prostatic Hyperplasia Treatment with New Physiotherapeutic Device

PURPOSE

Thermobalancing therapy, provided by Therapeutic Device, which contains a natural thermoelement, and is applied topically in the projection ofthe prostate,was aimed to improve blood circulation in the affected organ. We evaluated the effectiveness of new Therapeutic Device for the treatment of patients with benign prostatic hyperplasia (BPH).

MATERIALS AND METHODS

We performed a clinical non-randomized controlled trial before and after 6-month treatment. Therapeutic Device was administered to 124 patients with BPH as mono-therapy. The dynamic of the patients' condition was assessed by the International Prostate Symptom Score (IPSS), ultrasound measurement of prostate volume (PV) and uroflowmetry. The control-group comprised 124 men who did not receive any treatment. The IPSS score, maximum flow rate (Qmax), and PV were compared between the groups.

RESULTS

Baseline evaluation (pre-treatment) for both groups were comparable to each other with no clinically significant difference regarding age, IPSS score, Qmax and PV volume. Overall, thermobalancing therapy resulted in significant improvements from baseline to endpoint in IPSS (P = .001), IPSS storage and voiding subscores (both P = .001), and IPSS quality of life index (QoL) (P = .001) compared with control group. Moreover, comparison of parameters after 6 months treatment showed that thermobalancing therapy also improved the Qmax (P = .001), and PV (P = .001).

CONCLUSION

Two years clinical trial demonstrated that thermobalancing therapy administered for 6 months provides a marked improvement in patients presenting with symptomatic BPH not only on lower urinary tract symptoms (LUTS) but also in QoL and Qmax. Thus urologists should be aware about thermobalancing therapy as a non-invasive physiotherapeutic treatment option for treatment of BPH.

Time-multiplexed two-channel capacitive radiofrequency hyperthermia with nanoparticle mediation

BACKGROUND

Capacitive radiofrequency (RF) hyperthermia suffers from excessive temperature rise near the electrodes and poorly localized heat transfer to the deep-seated tumor region even though it is known to have potential to cure ill-conditioned tumors. To better localize heat transfer to the deep-seated target region in which electrical conductivity is elevated by nanoparticle mediation, two-channel capacitive RF heating has been tried on a phantom.

METHODS

We made a tissue-mimicking phantom consisting of two compartments, a tumor-tissue-mimicking insert against uniform background agarose. The tumor-tissue-mimicking insert was made to have higher electrical conductivity than the normal-tissue-mimicking background by applying magnetic nanoparticle suspension to the insert. Two electrode pairs were attached on the phantom surface by equal-angle separation to apply RF electric field to the phantom. To better localize heat transfer to the tumor-tissue-mimicking insert, RF power with a frequency of 26 MHz was delivered to the two channels in a time-multiplexed way. To monitor the temperature rise inside the phantom, MR thermometry was performed at a 3T MRI intermittently during the RF heating. Finite-difference-time-domain (FDTD) electromagnetic and thermal simulations on the phantom model were also performed to verify the experimental results.

RESULTS

As compared to the one-channel RF heating, the two-channel RF heating with time-multiplexed driving improved the spatial localization of heat transfer to the tumor-tissue-mimicking region in both the simulation and experiment. The two-channel RF heating also reduced the temperature rise near the electrodes significantly.

CONCLUSIONS

Time-multiplexed two-channel capacitive RF heating has the capability to better localize heat transfer to the nanoparticle-mediated tumor region which has higher electrical conductivity than the background normal tissues.

Physical Medicine Devices; Reclassification of Shortwave Diathermy for All Other Uses, Henceforth To Be Known as Nonthermal Shortwave Therapy. Final order; technical correction

The Food and Drug Administration (FDA) is issuing a final order to reclassify shortwave diathermy (SWD) for all other uses, a preamendments class III device, into class II (special controls), and to rename the device "nonthermal shortwave therapy'' (SWT). FDA is also making a technical correction in the regulation for the carrier frequency for SWD and SWT devices.

Study of thermal effect on breast tumor metabolism and growth using metabonomics

In this study, the biological effects of long-term mild hyperthermia treatment on tumor metabolism and growth were investigated using 4T1 murine mammary carcinoma, a common animal model of metastatic breast cancer. Periodic thermal treatment (12 hours per day) was applied to tumors and carried out for 3 days, 7 days, 14 days, and 21 days, respectively. The metabolites of tumor tissues were analyzed by gas chromatography-mass spectrometry. The results showed that the growth rate of thermally treated tumors was inversely related to the abundance of long chain fatty acids and acyl glycerols identified in tumor tissues. In the first two weeks, the growth of thermally treated tumors was significantly inhibited, while there was an obvious accumulation of long chain fatty acids and acyl glycerols in tumor tissues. In the third week, the thermally treated tumors adapted to the thermal environment and started to regrow, while the abundance of long chain fatty acids and acyl glycerols decreased in the tumor tissues. These observations suggested that the blockade of long chain fatty acid synthesis during mild hyperthermia treatment of tumors could improve the long-term treatment effect by limiting the supply of substance and energy for tumor re-growth.

Spatial and Temporal Control of Hyperthermia Using Real Time Ultrasonic Thermal Strain Imaging with Motion Compensation, Phantom Study

Mild hyperthermia has been successfully employed to induce reversible physiological changes that can directly treat cancer and enhance local drug delivery. In this approach, temperature monitoring is essential to avoid undesirable biological effects that result from thermal damage. For thermal therapies, Magnetic Resonance Imaging (MRI) has been employed to control real-time Focused Ultrasound (FUS) therapies. However, combined ultrasound imaging and therapy systems offer the benefits of simple, low-cost devices that can be broadly applied. To facilitate such technology, ultrasound thermometry has potential to reliably monitor temperature. Control of mild hyperthermia was previously achieved using a proportional-integral-derivative (PID) controller based on thermocouple measurements. Despite accurate temporal control of heating, this method is limited by the single position at which the temperature is measured. Ultrasound thermometry techniques based on exploiting the thermal dependence of acoustic parameters (such as longitudinal velocity) can be extended to create thermal maps and allow an accurate monitoring of temperature with good spatial resolution. However, in vivo applications of this technique have not been fully developed due to the high sensitivity to tissue motion. Here, we propose a motion compensation method based on the acquisition of multiple reference frames prior to treatment. The technique was tested in the presence of 2-D and 3-D physiological-scale motion and was found to provide effective real-time temperature monitoring. PID control of mild hyperthermia in presence of motion was then tested with ultrasound thermometry as feedback and temperature was maintained within 0.3°C of the requested value.

Regional hyperthermia of the abdomen, a pilot study towards the treatment of peritoneal carcinomatosis

BACKGROUND

Peritoneal carcinomatosis occurs in different cancer subtypes and is associated with a dismal prognosis. Some doubts remain whether the whole abdomen can be treated by regional hyperthermia, therefore we analyzed feasibility conducting a pilot study.

METHODS

A simulation of the abdominopelvic heat distribution in 11 patients with peritoneal carcinomatosis was done using the HyperPlan software and the SIGMA-60 and SIGMA-Eye applicators. Tissue-specific region-related electrical and thermal parameters were used to solve the Maxwell's equations and the bioheat-transfer equation. Three-dimensional specific absorption rate (SAR) distributions and, additionally, estimated region-related perfusion rates were used to solve the bioheat-transfer equation. The predicted SAR and temperature distributions were compared with minimally invasive measurements in pelvic reference points.

RESULTS

In 11 patients (7 of them treated in the SIGMA-60 and 4 in the SIGMA-Eye applicator) the measured treatment variables (SAR, temperatures in the pelvic reference points) indicated that the heated volumes were higher for the SIGMA-Eye applicator. The mean computed abdominal SARs were less for the SIGMA-Eye (33 versus 44 W/kg). Nevertheless, the temperature distributions in the abdomen (peritoneal cavity) were more homogeneous in the SIGMA-Eye applicator as compared to the SIGMA-60 as indicated by higher values of T90 (mean 40.2 versus 38.2 °C) and T50 (mean 41.1 versus 40.2 °C), while the maximum temperatures were similar (in the range 41 to 43 °C). Even though the mean abdominal SAR was lower in the SIGMA-Eye, the heat distribution covered a larger volume of the abdomen (in particular the upper abdomen). For the SIGMA-60 applicator the achieved T90 appeared to be limited between 41 and 42 °C, for the SIGMA Eye applicator more effective T90 in the range 42 to 43 °C were obtained.

CONCLUSION

Our results suggest that an adequate heating of the abdomen and therefore abdominal regional hyperthermia in PC patients appears feasible. The SIGMA-Eye applicator appears to be superior compared to the SIGMA-60 applicator for abdominal hyperthermia.

Influence of FBG sensors length on temperature measures in laser-irradiated pancreas: theoretical and experimental evaluation

Temperature distribution T(x,y,z,t) in tissue undergoing Laser-induced Interstitial Thermotherapy (LITT) plays a crucial role on treatment outcome. Theoretical and experimental assessment of temperature on ex vivo laser-irradiated pancreas is presented. The aim of this work is to assess the influence of thermometers dimensions on temperature measures during LITT. T(x,y,z,t) inside tissue is monitored by optical sensors, i.e., Fiber Bragg Gratings (FBGs): three FBGs with lengths of 10 mm and nine FBGs of 1 mm, at different distances (2 mm, 5 mm and 10 mm) and different quotes (0 mm, 2 mm and 4 mm) from the laser fiber tip are used. Theoretical punctual T(x,y,z,t) is averaged out on both 10 mm and 1 mm in order to compare numerical predictions with experimental data. Results demonstrate the influence of FBG length on T(x,y,z,t) measures. This phenomenon depends on the distance between sensor and applicator: it is particularly significant close to the applicator tip (2 mm) because of the high spatial T(x,y,z,t) gradient within the tissue. Both theoretical results and experimental ones show that just at a distance of 10 mm from the tip, differences between T(x,y,z,t) provided by FBGs of 10 mm and 1 mm are negligible.

Monitoring of temperature increase and tissue vaporization during laser interstitial thermotherapy of ex vivo swine liver by computed tomography

Laser interstitial thermotherapy (LITT) is a minimally invasive technique used to thermally destroy tumour cells. Being based on hyperthermia, LITT outcome depends on the temperature distribution inside the tissue. Recently, CT scan thermometry, based on the dependence of the CT number (HU) on tissue temperature (T) has been introduced during LITT; it is an attractive approach to monitor T because it overcomes the concerns related to the invasiveness. We performed LITT on nine ex vivo swine livers at three different laser powers, (P=1.5 W, P=3 W, P=5 W) with a constant treatment time t=200 s; HU is averaged on two ellipsoidal regions of interest (ROI) of 0.2 cm2, placed at two distances from the applicator (d=3.6 mm and d=8.7 mm); a reference ROI was placed away from the applicator (d=30 mm). The aim of this study is twofold: 1) to evaluate the effect of the T increase in terms of HU variation in ex vivo swine livers undergoing LITT; and 2) to estimate the P value for tissue vaporization. To the best of our knowledge, this is the first study focused on the HU variation in swine livers undergoing LITT at different P. The reported findings could be useful to assess the effect of LITT on the liver in terms of both T changes and tissue vaporization, with the aim to obtain an effective therapy.

Stretchable Heater Using Ligand-Exchanged Silver Nanowire Nanocomposite for Wearable Articular Thermotherapy

Thermal therapy is one of the most popular physiotherapies and it is particularly useful for treating joint injuries. Conventional devices adapted for thermal therapy including heat packs and wraps have often caused discomfort to their wearers because of their rigidity and heavy weight. In our study, we developed a soft, thin, and stretchable heater by using a nanocomposite of silver nanowires and a thermoplastic elastomer. A ligand exchange reaction enabled the formation of a highly conductive and homogeneous nanocomposite. By patterning the nanocomposite with serpentine-mesh structures, conformal lamination of devices on curvilinear joints and effective heat transfer even during motion were achieved. The combination of homogeneous conductive elastomer, stretchable design, and a custom-designed electronic band created a novel wearable system for long-term, continuous articular thermotherapy.

Rezūm System Water Vapor Treatment for Lower Urinary Tract Symptoms/Benign Prostatic Hyperplasia: Validation of Convective Thermal Energy Transfer and Characterization With Magnetic Resonance Imaging and 3-Dimensional Renderings

OBJECTIVE

To evaluate by magnetic resonance imaging the physical effects of convective thermal energy transfer with water vapor as a means of treating lower urinary tract symptoms due to benign prostatic hyperplasia.

METHODS

Sixty-five men with lower urinary tract symptoms were treated with the Rezūm System by transurethral intraprostatic injection of water vapor. A group of 45 of these men consented to undergo a series of gadolinium-enhanced magnetic resonance imagings of the prostate after treatment to monitor the size and location of ablative lesions, their time course of resolution, and the corresponding change in prostate tissue volume. Visualization was conducted at 1 week, 1, 3, and 6 months after treatment.

RESULTS

Outcomes were available for 44 patients. Convective thermal lesions were limited to the transition zone and correlated with targeted treatment locations. At 1 week after treatment, the mean volume of ablative lesions was 8.2 cm(3) (0.5-24.0 cm(3)). At 6 months, whole prostate volume was reduced by a mean of 28.9% and transition zone volume by 38.0% as compared with baseline 1-week images. At 3 and 6 months after treatment, the lesion volumes had reduced by 91.5% and 95.1%, respectively. Lesions remained within the targeted treatment zone without compromising integrity of the bladder, rectum, or striated urinary sphincter.

CONCLUSION

This imaging study confirms the delivery of convective water vapor technology to create thermal lesions in the prostate tissue. Lesions generated underwent near complete resolution by 3 and 6 months after treatment with a concomitant one-third reduction in overall prostate and transition zone volumes.

Alternating magnetic field-induced hyperthermia increases iron oxide nanoparticle cell association/uptake and flux in blood-brain barrier models

PURPOSE

Superparamagnetic iron oxide nanoparticles (IONPs) are being investigated for brain cancer therapy because alternating magnetic field (AMF) activates them to produce hyperthermia. For central nervous system applications, brain entry of diagnostic and therapeutic agents is usually essential. We hypothesized that AMF-induced hyperthermia significantly increases IONP blood-brain barrier (BBB) association/uptake and flux.

METHODS

Cross-linked nanoassemblies loaded with IONPs (CNA-IONPs) and conventional citrate-coated IONPs (citrate-IONPs) were synthesized and characterized in house. CNA-IONP and citrate-IONP BBB cell association/uptake and flux were studied using two BBB Transwell(®) models (bEnd.3 and MDCKII cells) after conventional and AMF-induced hyperthermia exposure.

RESULTS

AMF-induced hyperthermia for 0.5 h did not alter CNA-IONP size but accelerated citrate-IONP agglomeration. AMF-induced hyperthermia for 0.5 h enhanced CNA-IONP and citrate-IONP BBB cell association/uptake. It also enhanced the flux of CNA-IONPs across the two in vitro BBB models compared to conventional hyperthermia and normothermia, in the absence of cell death. Citrate-IONP flux was not observed under these conditions. AMF-induced hyperthermia also significantly enhanced paracellular pathway flux. The mechanism appears to involve more than the increased temperature surrounding the CNA-IONPs.

CONCLUSIONS

Hyperthermia induced by AMF activation of CNA-IONPs has potential to increase the BBB permeability of therapeutics for the diagnosis and therapy of various brain diseases.