Thermal Ablation Of Tumors Research Articles

Image-based computational model for focused ultrasound ablation of liver tumor

High-intensity focused ultrasound (HIFU) is a rapidly developing medical technology that allows non-invasive thermal ablation of tumors. Thermal treatment of liver tumor, which is one of the most common malignancies worldwide, is problematic because large blood vessels act as a heat sink. Convective cooling protects the cancer cells from thermal destruction and decreases the necrosed volume. A major objective of the method development is to achieve a virtually complete necrosis of tumors close to major blood vessels and to avoid blood vessel damage and, hence, the needed treatment planning. The present study is aimed at predicting liver tumor temperature during HIFU thermal ablation in a patient-specific liver geometry. The model comprises the nonlinear Westervelt equation and bioheat equations in the liver and blood vessels. The nonlinear hemodynamic equations are also taken into account with the convected cooling and acoustic streaming effects being taken into account. We found from this three-dimensional three-field coupling study that in large blood vessels, both convective cooling and acoustic streaming may change the temperature considerably near the blood vessel. More precisely, acoustic streaming velocity magnitude can be several times larger than the blood vessel velocity. The results presented in the current work can be further used to construct a surgical planning platform.

Emerging needle ablation technology in urology

Thermal ablation of urologic tumors in the form of freezing (cryoablation) and heating (radiofrequency ablation) have been utilized successfully to treat and ablate soft tissue tumors for over 15 years. Multiple studies have demonstrated efficacy nearing that of extirpative surgery for certain urologic conditions. There are technical limitations to their speed and safety profile because of the physical limits of thermal diffusion. Recently, there has been a desire to investigate other forms of energy in an effort to circumvent the limitations of cryoblation and radiofrequency ablation. This review will focus on three relatively new energy applications as they pertain to tissue ablation: microwave, irreversible electroporation, and water vapor. High-intensity-focused ultrasound nor interstitial lasers are discussed, as there have been no recently published updates. Needle and probe-based ablative treatments will continue to play an important role. As three-dimensional imaging workstations move from the advanced radiologic interventional suite to the operating room, surgeons will likely still play a pivotal role in the +-application of these probe ablative devices. It is essential that the surgeon understands the fundamentals of these devices in order to optimize their application.

Molecular changes in bone marrow, tumor and serum after conductive ablation of murine 4T1 breast carcinoma

Thermal ablation of solid tumors using conductive interstitial thermal therapy (CITT) produces coagulative necrosis in the center of ablation. Local changes in homeostasis for surviving tumor and systemic changes in circulation and distant organs must be understood and monitored in order to prevent tumor re-growth and metastasis. The purpose of this study was to use a mouse carcinoma model to evaluate molecular changes in the bone marrow and surviving tumor after CITT treatment by quantification of transcripts associated with cancer progression and hyperthermia, serum cytokines, stress proteins and the marrow/tumor cross-talk regulator stromal-derived factor 1. Analysis of 27 genes and 22 proteins with quantitative PCR, ELISA, immunoblotting and multiplex antibody assays revealed that the gene and protein expression in tissue and serum was significantly different between ablated and control mice. The transcripts of four genes (Cxcl12, Sele, Fgf2, Lifr) were significantly higher in the bone marrow of treated mice. Tumors surviving ablation showed significantly lower levels of the Lifr and Sele transcripts. Similarly, the majority of transcripts measured in tumors decreased with treatment. Surviving tumors also contained lower levels of SDF-1α and HIF-1α proteins whereas HSP27 and HSP70 were higher. Of 16 serum chemokines, IFNγ and GM-CSF levels were lower with treatment. These results indicate that CITT ablation causes molecular changes which may slow cancer cell proliferation. However, inhibition of HSP27 may be necessary to control aggressiveness of surviving cancer stem cells. The changes in bone marrow are suggestive of possible increased recruitment of circulatory cancer cells. Therefore, the possibility of heightened bone metastasis after thermal ablation needs to be further investigated and inhibition strategies developed, if warranted.

A multi-element interstitial ultrasound applicator for the thermal therapy of brain tumors

Interstitial thermal therapy is a minimally invasive treatment modality that has been used clinically for ablating both primary and secondary brain tumors. Here a multi-element interstitial ultrasound applicator is described that allows for increased spatial control during thermal ablation of tumors as compared to existing clinical devices. The device consists of an array of 56 ultrasound elements operating at 6 MHz, oriented on the seven faces of a 3.2 mm flexible catheter. The device was first characterized using the acoustic holography method to examine the functioning of the array. Then experiments were performed to measure heating in tissue-mimicking gel phantoms and ex vivo tissue samples using magnetic resonance imaging-based thermometry. Experimental measurements were compared with results obtained using numerical simulations. Last, simulations were performed to study the feasibility of using the device for thermal ablation in the brain. Experimental results show that the device can be used to induce a temperature rise of greater than 20 °C in ex vivo tissue samples and numerical simulations further demonstrate that tumors with diameters of greater than 30-mm could potentially be treated.

Hyperthermia-enhanced indocyanine green delivery for laser-induced thermal ablation of carcinomas

Purpose: Intravenous administration of indocyanine green (ICG) dye can effectively convert near-infrared (NIR) laser light into heat and enhance thermal injury of blood vessels; however, there is no selective uptake of ICG by the tumour compared to the other tissues, which impacts the therapeutic ratio of this strategy unless uptake can be selectively increased in tumour tissue. Here we investigated the use of local hyperthermia prior to intravenous ICG administration to enhance ICG uptake in tumour tissue, thereby enhancing laser thermal ablation of solid tumours. Methods: Murine SCK breast or SCCVII head and neck tumours were treated with a 755-nm laser light either alone or with prior intravenous administration of 4 mg/kg ICG and/or local tumour hyperthermia at 42.5 °C for 60 min. Retention of ICG was quantified using a NIR animal imaging system. Treatment effects were assessed by growth delay and histology. Results: ICG accumulation in the heated tumours was 1.23-fold greater on average compared to non-heated tumours, in both models. In SCK tumours, animals receiving either laser irradiation alone or in conjunction with ICG had a 1.86- or 3.91-fold increase in tumour growth delay, respectively. The addition of local hyperthermia before ICG injection resulted in complete regression of SCK tumours. Uptake of ICG increased in SCCVII tumours; however, little change in tumour growth delay was observed. Conclusion: Using local hyperthermia may improve the delivery of ICG to the tumour and thereby increase the extent of laser thermal ablation of smaller superficial malignancies that can be effectively exposed to laser therapy.

Image-guided Thermal Ablation of Tumor Increases the Plasma Level of Interleukin-6 and Interleukin-10: Is Plasma Level of Interleukin-6 a Surrogate for Immunogenic Cell Death?

Image-guided Thermal Ablation of Tumor Increases the Plasma Level of Interleukin-6 and Interleukin-10: Is Plasma Level of Interleukin-6 a Surrogate for Immunogenic Cell Death?

Biomechanical properties of bone treated by magnetic resonance-guided focused ultrasound — an in vivo porcine model study

The magnetic resonance-guided focused ultrasound (MRgFUS) system uses MR imaging for real-time aiming of thermal ablation of bone and soft tissue tumors. Past clinical studies showed no increase in fracture rate after MRgFUS treatment. The purpose of this study was to determine the effect of MRgFUS treatment on mechanical properties of bone and correlate the effect to histological findings of treated bone. Four fully grown mini-pigs were treated by MRgFUS. Six consecutive right normal ribs were treated in each animal, and the left corresponding ribs served as controls. The animals were sacrificed at pre-set intervals (0, 2, 6 and 12weeks after treatment), and the treated and control bones were extracted. Mechanical properties of each bone were examined using three points bending studies for comparing treated bones to the corresponding controls. Histologic properties using Masson and hematoxylin–eosin stains were also compared. The ratio between treated and control biomechanical properties showed reduction in bone biomechanical properties at 6weeks post-MRgFUS treatment. The mean±SD yield load ratio and maximum ratios were 0.69±0.11 and 0.71±0.13, respectively (both p=0.031). These findings showed some recovery trend at 12weeks after treatment. Histological analysis showed a reduction in mean osteon size at 2weeks after treatment (0.58×10−3±0.1×10−3mm and 0.16×10−3±0.017×10−3mm) in control vs. treated bones, respectively (p=0.005). Treatment with the MRgFUS system resulted in a ~30% reduction in mechanical strength at 6weeks post-treatment. The reduction showed a reversible trend, with a 25%–20% decrease in strength at 12weeks post-treatment.

Complications of thermal ablation of hepatic tumors: Comparison of radiofrequency and microwave techniques.

e15040 Background: The efficacy and safety of radiofrequency ablation (RFA) have been reported in the literatures, which are considered as frontline choice for treatment of liver cancer. Recently, microwave ablation (MWA) has emerged and gained great attention over RFA. However, in comparison to RFA, the safety of MWA for treatment of liver cancer has not been fully reported in the literatures. Studies with large clinical data sets are still needed to understand the technique and avoid the complications. The objective of this study was to retrospectively investigate the common complications of thermal ablations of liver tumors using both RFA and MWA techniques, and compare the safety between these two procedures. Methods: This retrospective study protocol was approved by our institutional ethics committee to allow investigators to review the existing patient’s medical records. A total of 879 patients with hepatic tumors underwent thermal ablation. There were 323 cases having the RFA procedures and 556 cases having MWA procedures. The complications of thermal ablations of liver tumors were compared using both RFA and MWA techniques. Results: A total of 1,030 thermal ablation sessions was performed in 879 patients with a total of 1,652 tumors. There were 323 patients with 562 tumors received a total of 376 RFA with averaged 1.16±0.48 sessions per patient. The other 556 patients with 1,090 tumors received a total of 654 MWA with averaged1.18±0.51 sessions per patient. The mortality rates were 0.31% (1/323) and 0.36% (2/556) in RFA and MWA group. In RFA and MWA group, the major complication rates were 3.5% (13/376) and 3.1% (20/654) (Table 1), meanwhile the minor complication rates were 5.9% (22/376) and 5.7% (37/654). There was no statistical significant difference for the mortality rates, the major complications, the minor complications between the RFA and MWA groups (P>0.05). Conclusions: Thermal ablation therapy in the treatment of liver cancers is relatively safe with low mortality and low incidence of serious complications. The types and incidences of complications caused by RFA and MWA are similar and comparable for safety consideration in clinical settings.

The impact of vaporized nanoemulsions on ultrasound-mediated ablation.

BackgroundThe clinical feasibility of using high-intensity focused ultrasound (HIFU) for ablation of solid tumors is limited by the high acoustic pressures and long treatment times required. The presence of microbubbles during sonication can increase the absorption of acoustic energy and accelerate heating. However, formation of microbubbles within the tumor tissue remains a challenge. Phase-shift nanoemulsions (PSNE) have been developed as a means for producing microbubbles within tumors. PSNE are emulsions of submicron-sized, lipid-coated, and liquid perfluorocarbon droplets that can be vaporized into microbubbles using short (<1 ms), high-amplitude (>5 MPa) acoustic pulses. In this study, the impact of vaporized phase-shift nanoemulsions on the time and acoustic power required for HIFU-mediated thermal lesion formation was investigated in vitro.MethodsPSNE containing dodecafluoropentane were produced with narrow size distributions and mean diameters below 200 nm using a combination of sonication and extrusion. PSNE was dispersed in albumin-containing polyacrylamide gel phantoms for experimental tests. Albumin denatures and becomes opaque at temperatures above 58°C, enabling visual detection of lesions formed from denatured albumin. PSNE were vaporized using a 30-cycle, 3.2-MHz, at an acoustic power of 6.4 W (free-field intensity of 4,586 W/cm2) pulse from a single-element, focused high-power transducer. The vaporization pulse was immediately followed by a 15-s continuous wave, 3.2-MHz signal to induce ultrasound-mediated heating. Control experiments were conducted using an identical procedure without the vaporization pulse. Lesion formation was detected by acquiring video frames during sonication and post-processing the images for analysis. Broadband emissions from inertial cavitation (IC) were passively detected with a focused, 2-MHz transducer. Temperature measurements were acquired using a needle thermocouple.ResultsBubbles formed at the HIFU focus via PSNE vaporization enhanced HIFU-mediated heating. Broadband emissions detected during HIFU exposure coincided in time with measured accelerated heating, which suggested that IC played an important role in bubble-enhanced heating. In the presence of bubbles, the acoustic power required for the formation of a 9-mm3 lesion was reduced by 72% and the exposure time required for the onset of albumin denaturation was significantly reduced (by 4 s), provided that the PSNE volume fraction in the polyacrylamide gel was at least 0.008%.ConclusionsThe time or acoustic power required for lesion formation in gel phantoms was dramatically reduced by vaporizing PSNE into bubbles. These results suggest that PSNE may improve the efficiency of HIFU-mediated thermal ablation of solid tumors; thus, further investigation is warranted to determine whether bubble-enhanced HIFU may potentially become a viable option for cancer therapy.

Image-guided Thermal Ablation of Tumors Increases the Plasma Level of Interleukin-6 and Interleukin-10

PurposeTo identify changes in plasma cytokine levels after image-guided thermal ablation of human tumors and to identify the factors that independently predict changes in plasma cytokine levels. Materials and MethodsWhole-blood samples were collected from 36 patients at three time points: before ablation, after ablation (within 48 hours), and at follow-up (1–5 weeks after ablation). Plasma levels of interleukin (IL)-1α, IL-2, IL-6, IL-10, and tumor necrosis factor (TNF)-α were measured using a multiplex immunoassay. Univariate and multivariate analyses were performed using cytokine level as the dependent variable and sample collection, time, age, sex, primary diagnosis, metastatic status, ablation site, and ablation type as the independent variables. ResultsThere was a significant increase in the plasma level of IL-6 after ablation compared with before ablation (9.6-fold±31-fold, P<.002). IL-10 also showed a significant increase after ablation (1.9-fold±2.8-fold, P<.02). Plasma levels of IL-1α, IL-2, and TNF-α were not significantly changed after ablation. Cryoablation resulted in the largest change in IL-6 level (>54-fold), whereas radiofrequency ablation and microwave ablation showed 3.6-fold and 3.4-fold changes, respectively. Ablation of melanomas showed the largest change in IL-6 48 hours after ablation (92×), followed by ablation of kidney (26×), liver (8×), and lung (6×) cancers. Multivariate analysis revealed that ablation type (P<.0003) and primary diagnosis (P<.03) were independent predictors of changes to IL-6 after ablation. Age was the only independent predictor of IL-10 levels after ablation (P< .019). ConclusionsImage-guided thermal ablation of tumors increases plasma levels of IL-6 and IL-10, without increasing plasma levels of IL-1α, IL-2, or TNF-α.

Abstract No. 399 - Organ protection during thermal ablation of tumors touching critical anatomy, such as the heart, bowel, or nerves

Purpose To describe and characterize unconventional techniques for protecting organs during thermal ablation of tumors touching critical structures. Materials and Methods Retrospective analysis was performed of patients undergoing thermal ablation near heart, nerves, colon, rectum, duodenum, and gallbladder. Clinical records, lab values, imaging features, and procedural technical details were reviewed and collated in terms of organ protected, maneuver performed, volumes of hydro-dissection, degree of hyponatremia induced by 5 % dextrose intraperitoneal hydrodissection, and long term outcome in cases where nerves were injured. Results Non-target organ protection was successful for thermal ablation of tumors adjacent to heart, gallbladder, stomach, duodenum, colon, rectum, nerves, ureter. Hydrodissection was performed in a wide variety of locations and resulted in significant post-procedural hyponatremia in certain large volume infusions. Hydrodissection was not successful in certain post-operative patients, possibly limited by adhesions. Transhepatic hydrodissection is described, as well as pharmacologic maneuvers for gallbladder contraction, and stomoach or gut peristalsis. IV hydration with normal saline potentially corrected for hyponatremia. Nerve damage evident as parasthesias and numbness, was most often seen when hydrodissection was not used at all, and painful parasthesias were generally responsive to Gabapentin, when indicated. The liver was able to be rotated caudally (clockwise when facing patient) with large volume (up to 3 liters) hydrodissection, to avoid heart injury during successful ablation of tumors touching the heart. Conclusion Tumors touching the heart, bowel, or expected location of nerves may be successfuly ablated with targeted or large volume hydrodissection. IV normal saline can correct hyponatremia resulting from 5 % dextrose hydrodissection.

MR-gesteuerter fokussierter Ultraschall

High-intensity focused ultrasound (synonyms FUS and HIFU) under magnetic resonance imaging (MRI) guidance (synonyms MRgFUS and MR-HIFU) is a completely non-invasive technology for accurate thermal ablation of a target tissue while neighboring tissues and organs are preserved.The combination of FUS with MRI for planning, (near) real-time monitoring and outcome assessment of treatment markedly enhances the safety of the procedure.The MRgFUS procedure is clinically established in particular for the treatment of symptomatic uterine fibroids, followed by palliative ablation of painful bone metastases. Furthermore, promising results have been shown for the treatment of adenomyosis, malignant tumors of the prostate, breast and liver and for various intracranial applications, such as thermal ablation of brain tumors, functional neurosurgery and transient disruption of the blood-brain barrier.

Complications of thermal ablation of hepatic tumours: Comparison of radiofrequency and microwave ablative techniques

To investigate the common complications of thermal ablation of liver tumours using both radiofrequency ablation (RFA) and microwave ablation (MWA) techniques, and to compare the safety of these two procedures. This retrospective study protocol was approved by the institution's ethics committee to allow investigators to review existing patient medical records. A total of 879 patients with hepatic tumours underwent thermal ablation; 323 patients underwent RFA and 556 underwent MWA. The complications of the RFA and MWA techniques were compared. A total of 1030 thermal ablation sessions was performed in 879 patients with a total of 1652 tumours. Three hundred and twenty-three patients with 562 tumours received a total of 376 RFA sessions with an average of 1.16 ± 0.48 sessions per patient. The other 556 patients with 1090 tumours received a total of 654 MWA with an average 1.18 ± 0.51 sessions per patient. The mortality rates were 0.31% (1/323) and 0.36% (2/556) in RFA and MWA group. In RFA and MWA group, the major complication rates were 3.5% (13/376) and 3.1% (20/654), meanwhile the minor complication rates were 5.9% (22/376) and 5.7% (37/654). There was no statistically significant difference in the mortality rates, major complications, and minor complications between the RFA and MWA groups (p > 0.05). Thermal ablation therapy in the treatment of liver cancers is relatively safe with low mortality and a low incidence of serious complications. The types and incidences of complications caused by RFA and MWA are similar and comparable for safety consideration in clinical settings.

A system for MRI‐guided transperineal delivery of needles to the prostate for focal therapy

To demonstrate the capabilities of a new magnetic resonance imaging (MRI)-guided system for delivering needles to the prostate for focal therapy. Included is a presentation of the design of the system and its user interface, evaluation of MR-compatibility, and quantitative evaluation of guidance accuracy and repeatability within the bore of a clinical MRI scanner. The use of MRI for visualization of tumors, intraoperative visualization of interventional tools, and thermometry for controlled ablation of lesions is becoming increasingly prevalent. In this work, the authors present a prototype system for guiding needles to prostate tumors within the bore of an MRI scanner for use in focal laser thermal ablation of prostate tumors. The system consists of a manually actuated trajectory alignment device that allows a physician to precisely align a set of needle guides with an intended target in the prostate within the bore of a clinical closed-bore MRI scanner. Needle insertion is then performed transperineally, with the patient in the bore of the MRI, and custom software provides monitoring of thermal ablative procedures. The system is shown to have a minimal effect on image distortion, and only a 6% decrease in image signal-to-noise ratio. Through needle insertion tests in tissue-mimicking phantoms, the system's potential for reliably guiding needles to intra-MR targets within 2.64 mm has been demonstrated. Use of the system to deliver focal laser ablation therapy to two patients showed that it can be used to deliver needles with minimal disruption of workflow, and in less time than when insertions are performed freehand or with a fixed grid template. A system for delivering needles to a patient's prostate for focal therapy within the bore of an MRI scanner has been developed. Results from needle insertion tests in phantoms suggest that the system has the potential to provide accurate delivery of focal therapy to prostate tumors of the smallest clinically significant size. Initial tests in two patients showed that needle deflection was larger than in phantoms, but methods of manually compensating for this effect were employed and needles were delivered to treatment sites with sufficient accuracy to deliver effective treatment. In addition, the treatment was delivered in less time than with a fixed grid template or freehand insertions. Despite this success, methods of reducing needle deflection are needed in order to fully utilize the potential of this system, and further reduce total procedure time.

Low-pressure pulsed focused ultrasound with microbubbles promotes an anticancer immunological response

BackgroundHigh-intensity focused-ultrasound (HIFU) has been successfully employed for thermal ablation of tumors in clinical settings. Continuous- or pulsed-mode HIFU may also induce a host antitumor immune response, mainly through expansion of antigen-presenting cells in response to increased cellular debris and through increased macrophage activation/infiltration. Here we demonstrated that another form of focused ultrasound delivery, using low-pressure, pulsed-mode exposure in the presence of microbubbles (MBs), may also trigger an antitumor immunological response and inhibit tumor growth.MethodsA total of 280 tumor-bearing animals were subjected to sonographically-guided FUS. Implanted tumors were exposed to low-pressure FUS (0.6 to 1.4 MPa) with MBs to increase the permeability of tumor microvasculature.ResultsTumor progression was suppressed by both 0.6 and 1.4-MPa MB-enhanced FUS exposures. We observed a transient increase in infiltration of non-T regulatory (non-Treg) tumor infiltrating lymphocytes (TILs) and continual infiltration of CD8+ cytotoxic T-lymphocytes (CTL). The ratio of CD8+/Treg increased significantly and tumor growth was inhibited.ConclusionsOur findings suggest that low-pressure FUS exposure with MBs may constitute a useful tool for triggering an anticancer immune response, for potential cancer immunotherapy.

Irreversible Electroporation for the Ablation of Liver Tumors

To explore irreversible electroporation (IRE) as a novel, nonthermal form of tissue ablation using high-voltage electrical current to induce pores in the lipid bilayer of cells, resulting in cell death. PubMed searches were performed using the keywords electroporation, IRE, and ablation. The abstracts for the 2012 meetings of both the American Hepato-Pancreato-Biliary Association and the Society for Interventional Radiology were also searched. All articles and abstracts with any reference to electroporation were identified and reviewed. All studies and abstracts pertaining to electroporation. All data pertaining to the safety and efficacy of IRE were extracted from preclinical and clinical studies. Preclinical data detailing the theory and design of IRE systems were also extracted. Preclinical studies have suggested that IRE may have advantages over conventional forms of thermal tumor ablation including no heat sink effect and preservation of the acellular elements of tissue, resulting in less unwanted collateral damage. The early clinical experience with IRE demonstrates safety for the ablation of human liver tumors. Short-term data regarding oncologic outcome is now emerging and appears encouraging. Irreversible electroporation is likely to fill a niche void for the ablation of small liver tumors abutting a major vascular structure and for ablation of tumors abutting a major portal pedicle where heat sink and collateral damage must be avoided for maximum efficacy and safety. Studies are still needed to define the short-term and long-term oncologic efficacy of IRE.

Spatially controlled photothermal heating of bladder tissue through single-walled carbon nanohorns delivered with a fiberoptic microneedle device

Laser-based photothermal therapies for urothelial cell carcinoma (UCC) are limited to thermal ablation of superficial tumors, as treatment of invasive lesions is hampered by shallow light penetration in bladder tissue at commonly used therapeutic wavelengths. This study evaluates the utilization of sharp, silica, fiberoptic microneedle devices (FMDs) to deliver single-walled carbon nanohorns (SWNHs) serving as exogenous chromophores in conjunction with a 1,064-nm laser to amplify thermal treatment doses in a spatially controlled manner. Experiments were conducted to determine the lateral and depth dispersal of SWNHs in aqueous solution (0.05mg/mL) infused through FMDs into the wall of healthy, inflated, ex vivo porcine bladders. SWNH-perfused bladder regions were irradiated with a free-space, CW, 1,064-nm laser in order to determine the SWNH efficacy as exogenous chromophores within the organ. SWNHs infused at a rate of 50μL/min resulted in an average lateral expansion rate of 0.36 ± 0.08cm(2)/min. Infused SWNHs dispersal depth was limited to the urothelium and muscular propria for 50μL/min infusions of 10min or less, but dispersed through the entire thickness after a 15-min infusion period. Irradiation of SWNH-perfused bladder tissue with 1,064nm laser light at 0.95W/cm(2) over 40s exhibited a maximum increase of approximately 19°C compared with an increase of approximately 3°C in a non-perfused control. The results indicate that these silica FMDs can successfully penetrate into the bladder wall to rapidly distribute SWNHs with some degree of lateral and depth control and that SWNHs may be a viable exogenous chromophore for photothermal amplification of laser-based UCC treatments.

Contrast enhanced ultrasound: Roles in immediate post-procedural and 24-h evaluation of the effectiveness of thermal ablation of liver tumors

PurposeTo retrospectively assess the diagnostic accuracy of immediate post-procedural CEUS, 24-h CEUS, and 24-h CT in verifying the effectiveness of thermal ablation of liver tumors ablation, using the combined results of 3-month post-procedure CEUS and MDCT as the reference standard. Materials and methodsFrom our database, we selected patients who had immediate post-procedural CEUS and 24-h CEUS and MDCT examinations after undergoing thermal ablation of a liver tumor between January 2009 and March 2010. The study population consisted of 53 subjects and 55 tumors (44 HCC and 11 metastasis) were evaluated. Thirty-seven tumors were treated with radiofrequency and 18 with microwave ablation.Post-procedural CEUS, 24-h CEUS and MDCT, and 3-month follow-up CEUS and MDCT images were blindly reviewed by two radiologists, who measured the size of the ablation area on the post-procedural and 24-h studies. They also evaluated the ability of each of these three index tests to predict the outcome (residual tumor vs. no residual tumor) using imaging studies done at the 3-month follow-up as the reference standard. ResultsMean tumor diameter on preablation CEUS (the day before treatment) was 20 ± 9 mm. Mean diameter of the necrotic area was 29 ± 9 mm on post-procedural CEUS, 34 ± 11 mm on 24-h CEUS, and 36 ± 11 mm on 24-h MDCT. Diameters of the necrotic area (mean and maximum) on post-procedural CEUS were significantly smaller than those measured on 24-h CEUS or 24-h MDCT, which were not significantly different. For predicting the presence of residual tumor at the 3-month follow-up, post-procedural CEUS, 24-h CEUS, and 24-h MDCT displayed sensitivity of 33%, 33%, and 42%; specificity of 92%, 97%, and 97%; negative predictive value of 84%, 85%, and 83%. The accuracy parameters of these three imaging modalities were not significantly different from one another. ConclusionsIn patients undergoing thermal ablation for liver tumors, the immediate post-procedural CEUS seems comparable to 24-h CEUS and MDCT in terms of detecting residual disease.

Active targeting nanoparticle for breast cancer diagnosis and treatment.

163 Background: Breast cancer remains a major ongoing public health problem among women. Nanotechnology is the exciting field focused on man-made materials in the size range of 1-100 nanometers (nm). Nanoparticles (NPs) are on the scale of many cellular-level processes and hence are attractive for targeting breast cancer. Emerging nanotechnologies promise new approaches to early detection and treatment of breast cancer. Our group has reported Gold Speckled Silica NPs (GSS) as multimodal contrast agents for fluorescence, magnetic resonance and photoacoustic tomographic (PAT) imaging. The near infrared (NIR) optical absorption property of these particles makes them potentially useful for therapeutic applications such as thermal ablation of tumors. Fulfilling the promise of nanotechnologies for patients with metastatic breast cancer, necessitates delivery of nanomaterials to sites of breast cancer. Now we have focused on the cancer metabolism, we have recently developed active targeting NPs with surface functionalizing agent such as glucose conjugated NPs. We hypothesize that active targeting NPs is more incorporated into cancer cells compared to normal NPs. Methods: Human breast cancer cells, BT474, were incubated with active targeting NPs or normal NPs (as control). The tumor cell uptake was assessed using flow cytometry and fluorescence microscopy experiments. Results: Uptake of active targeting NPs was significantly higher than uptake of normal NPs. Conclusions: Active targeting NPs can be used as suitable targeting NPs for development of imaging agents for early diagnosis of breast cancer. Evolving bio-nanotechnologies such as active targeting NPs promise to enhance the early detection and non-invasive treatment of breast cancer.

1426P - Pain Palliation of Bone Metastases Using Magnetic Resonance Guided Focused Ultrasound - Multi-Center Multi-trial Results

ABSTRACT Introduction Magnetic Resonance guided Focused Ultrasound (MRgFUS) is a non-invasive, non-ionizing treatment for thermal ablation of tumors. The technology uses high intensity focused ultrasound ablation combined with continuous MR imaging to denervate pain. Precise targeting of the lesion and real time monitoring of tissue temperature rise are cornerstones of the technique. We present here results of multiple multi-center studies evaluating the safety and effectiveness of MRgFUS for painful bone metastases. Methods 93 patients with painful bone metastases underwent MRgFUS in 14 medical centers worldwide. Treated lesions had to be remote from nervous structures or joints. Effectiveness of pain palliation was evaluated with a standardized 11-point pain rating scale (0-no pain/10-worst pain) and by monitoring changes in pain-relieving medication. A reduction of 2 points or more was considered a significant response. Safety events were recorded and evaluated by severity. Results of 31 patients treated in initial safety studies were previously reported by Liberman et al (Ann Surg Oncol. 2009 Jan; 16(1):140-6). Results 107 procedures were performed, targeting 96 lesions in 93 patients. 3 patients were treated twice targeting a different lesion; another 11 patients underwent a second treatment due to large lesions. Patients were followed-up for a period of 3 months. Pain response was relatively rapid: within 3 days, on average, the clinical endpoint was met and maintained. Pain scores averaged 6.9 pre-treatment, decreased to 4.5 within 3 days post-treatment, to 3.3 at one month post-treatment, and further decreased to 2.6 at three month follow-up. There were no serious adverse events related to the treatment. 2 patients had mild skin erythema following the treatment and 5 patients (5%) had pain progression. Our updated results are similar to early reports. Conclusions The presented results clearly show that MRgFUS can provide a quick, effective and safe palliative therapy for patients suffering from painful bone metastases. Current results are consistent with initial reported results. Randomized trials are being conducted in patients as a first line treatment of painful bone metastases vs. radiation therapy and in patients who failed radiation therapy vs. sham. Disclosure L. Shay Levi: I work in InSightec as the global bone applications specialist. InSightec is the company sponsered these clinical trials. All other authors have declared no conflicts of interest.