Thermal Ablation Treatment Research Articles

Surgical Salvage of Thermal Ablation Failures for Renal Cell Carcinoma

Cryoablation and radio frequency ablation are attractive modalities for small renal masses in patients with substantial comorbidities. However, salvage extirpative therapy for local recurrence after thermal ablation can be challenging due to associated perinephric fibrosis. Patients with thermal ablation refractory tumors requiring surgical salvage from 1997 to 2013 were identified and retrospectively reviewed. A total of 27 patients were treated surgically after cryoablation (18) or radio frequency ablation (9) failed. Subjective assessment indicated moderate/severe fibrosis in 22 cases (81%). Partial nephrectomy was preferred in all patients but was not possible in 12, primarily due to unfavorable tumor size/location. In theintended partial nephrectomy group (15) open surgery was performed in all patients and completed in 14, with the procedure aborted in 1 due to extensive perinephric fibrosis. Radical nephrectomy was planned in 12 patients, of whom 8 were treated laparoscopically with 1 requiring conversion to open. Median estimated blood loss was 225 ml. Overall 17 patients experienced no complications and 4 had minor complications. However, 6 patients experienced more significant complications (Clavien III-IVb). Since January 2008 partial nephrectomy was performed more frequently (12 of 17, or 71% vs 2 of 10, or 20% for previous cases, p=0.02). Surgical salvage after failed thermal ablation is feasible in most instances, and partial nephrectomy is often possible but can be challenging due to associated perinephric fibrosis. The difficulty of surgical salvage should be recognized as a potential limitation of the thermal ablation treatment strategy. Prospective studies of thermal ablation vs partial nephrectomy should be prioritized to provide higher quality data about the merits and limitations of each approach.

WE‐G‐303‐04: Intrinsically Radiolabeled Nanoparticles: An Emerging Paradigm

Over the last decade, there has been a growing interest in applying nanotechnology to cancer detection, treatment, and treatment monitoring. Advances in nanotechnology have enabled the fabrication of nanoparticles from various materials with different shapes and sizes. Nanoparticles can be accumulated preferentially within tumors by either “passive targeting” through a phenomenon typically known as “enhanced permeability and retention” or “active targeting” in which nanoparticles are conjugated with antibodies or peptides directed against tumor and/or stromal markers. The tumor specificity of nanoparticles in conjunction with their unique physicochemical properties offers many novel strategies for cancer treatment and detection. For example, notable approaches in the radiation oncology setting include the use of gold nanoparticles for radiation response modulation of tumor or normal tissue and thermal ablation or hyperthermia treatment of tumors. Some of these approaches are currently being tested either on humans or on animals and, very likely, will become the clinical reality in the near future. Various computational and experimental techniques have also been applied to address unique research issues associated with nanoparticles and may become the standard tools for future investigations and clinical translations. Therefore, both clinicians and researchers may need to be properly educated about the basic principles as well as the promise of nanoparticle‐based applications with regard to the future of cancer diagnostics and therapeutics.This symposium will familiarize the audience with the potential applications of nanoparticles in oncologic imaging and therapy using specific illustrative examples. The audience will be properly oriented by these illustrative examples to the multiple avenues for collaborative research amongst interdisciplinary teams of physicists, clinicians, engineers, chemists, and biologists in industry and academia.Learning Objectives: Understand the physical bases of gold nanoparticle applications for radiosensitization and x‐ray fluorescence imaging Understand the parameters that define gold nanoparticle‐mediated radiosensitization in biological systems Understand the potential of magnetic nanoparticle characterization of the microenvironment Understand the various strategies for radiolabeling of nanoparticles and their applications S.C. and S.K. acknowledge support from MD Anderson Cancer Center, NIH (R01CA155446 and P30CA16672) and DoD (W81XWH‐12‐1‐0198); J.W. acknowledges support from NIH (U54CA151662‐01); W.C. acknowledges support from the University of Wisconsin‐Madison, NIH (R01CA169365, P30CA014520, and T32CA009206), DoD (W81XWH‐11‐1‐0644 and W81XWH‐11‐1‐0648), and ACS (125246‐RSG‐13‐099‐01‐CCE).

WE‐G‐303‐01: Physical Bases for Gold Nanoparticle Applications in Radiation Oncology and X‐Ray Imaging

Over the last decade, there has been a growing interest in applying nanotechnology to cancer detection, treatment, and treatment monitoring. Advances in nanotechnology have enabled the fabrication of nanoparticles from various materials with different shapes and sizes. Nanoparticles can be accumulated preferentially within tumors by either “passive targeting” through a phenomenon typically known as “enhanced permeability and retention” or “active targeting” in which nanoparticles are conjugated with antibodies or peptides directed against tumor and/or stromal markers. The tumor specificity of nanoparticles in conjunction with their unique physicochemical properties offers many novel strategies for cancer treatment and detection. For example, notable approaches in the radiation oncology setting include the use of gold nanoparticles for radiation response modulation of tumor or normal tissue and thermal ablation or hyperthermia treatment of tumors. Some of these approaches are currently being tested either on humans or on animals and, very likely, will become the clinical reality in the near future. Various computational and experimental techniques have also been applied to address unique research issues associated with nanoparticles and may become the standard tools for future investigations and clinical translations. Therefore, both clinicians and researchers may need to be properly educated about the basic principles as well as the promise of nanoparticle‐based applications with regard to the future of cancer diagnostics and therapeutics.This symposium will familiarize the audience with the potential applications of nanoparticles in oncologic imaging and therapy using specific illustrative examples. The audience will be properly oriented by these illustrative examples to the multiple avenues for collaborative research amongst interdisciplinary teams of physicists, clinicians, engineers, chemists, and biologists in industry and academia.Learning Objectives: Understand the physical bases of gold nanoparticle applications for radiosensitization and x‐ray fluorescence imaging Understand the parameters that define gold nanoparticle‐mediated radiosensitization in biological systems Understand the potential of magnetic nanoparticle characterization of the microenvironment Understand the various strategies for radiolabeling of nanoparticles and their applications S.C. and S.K. acknowledge support from MD Anderson Cancer Center, NIH (R01CA155446 and P30CA16672) and DoD (W81XWH‐12‐1‐0198); J.W. acknowledges support from NIH (U54CA151662‐01); W.C. acknowledges support from the University of Wisconsin‐Madison, NIH (R01CA169365, P30CA014520, and T32CA009206), DoD (W81XWH‐11‐1‐0644 and W81XWH‐11‐1‐0648), and ACS (125246‐RSG‐13‐099‐01‐CCE).

WE‐G‐303‐03: Advances in in Vivo Magnetic NanoparticleSensing

Over the last decade, there has been a growing interest in applying nanotechnology to cancer detection, treatment, and treatment monitoring. Advances in nanotechnology have enabled the fabrication of nanoparticles from various materials with different shapes and sizes. Nanoparticles can be accumulated preferentially within tumors by either “passive targeting” through a phenomenon typically known as “enhanced permeability and retention” or “active targeting” in which nanoparticles are conjugated with antibodies or peptides directed against tumor and/or stromal markers. The tumor specificity of nanoparticles in conjunction with their unique physicochemical properties offers many novel strategies for cancer treatment and detection. For example, notable approaches in the radiation oncology setting include the use of gold nanoparticles for radiation response modulation of tumor or normal tissue and thermal ablation or hyperthermia treatment of tumors. Some of these approaches are currently being tested either on humans or on animals and, very likely, will become the clinical reality in the near future. Various computational and experimental techniques have also been applied to address unique research issues associated with nanoparticles and may become the standard tools for future investigations and clinical translations. Therefore, both clinicians and researchers may need to be properly educated about the basic principles as well as the promise of nanoparticle‐based applications with regard to the future of cancer diagnostics and therapeutics.This symposium will familiarize the audience with the potential applications of nanoparticles in oncologic imaging and therapy using specific illustrative examples. The audience will be properly oriented by these illustrative examples to the multiple avenues for collaborative research amongst interdisciplinary teams of physicists, clinicians, engineers, chemists, and biologists in industry and academia.Learning Objectives: Understand the physical bases of gold nanoparticle applications for radiosensitization and x‐ray fluorescence imaging Understand the parameters that define gold nanoparticle‐mediated radiosensitization in biological systems Understand the potential of magnetic nanoparticle characterization of the microenvironment Understand the various strategies for radiolabeling of nanoparticles and their applications S.C. and S.K. acknowledge support from MD Anderson Cancer Center, NIH (R01CA155446 and P30CA16672) and DoD (W81XWH‐12‐1‐0198); J.W. acknowledges support from NIH (U54CA151662‐01); W.C. acknowledges support from the University of Wisconsin‐Madison, NIH (R01CA169365, P30CA014520, and T32CA009206), DoD (W81XWH‐11‐1‐0644 and W81XWH‐11‐1‐0648), and ACS (125246‐RSG‐13‐099‐01‐CCE).

WE‐G‐303‐02: Gold Nanoparticles as Radiosensitizers ‐ What Does It Take To Go From the Bench to the Bedside?

Over the last decade, there has been a growing interest in applying nanotechnology to cancer detection, treatment, and treatment monitoring. Advances in nanotechnology have enabled the fabrication of nanoparticles from various materials with different shapes and sizes. Nanoparticles can be accumulated preferentially within tumors by either “passive targeting” through a phenomenon typically known as “enhanced permeability and retention” or “active targeting” in which nanoparticles are conjugated with antibodies or peptides directed against tumor and/or stromal markers. The tumor specificity of nanoparticles in conjunction with their unique physicochemical properties offers many novel strategies for cancer treatment and detection. For example, notable approaches in the radiation oncology setting include the use of gold nanoparticles for radiation response modulation of tumor or normal tissue and thermal ablation or hyperthermia treatment of tumors. Some of these approaches are currently being tested either on humans or on animals and, very likely, will become the clinical reality in the near future. Various computational and experimental techniques have also been applied to address unique research issues associated with nanoparticles and may become the standard tools for future investigations and clinical translations. Therefore, both clinicians and researchers may need to be properly educated about the basic principles as well as the promise of nanoparticle‐based applications with regard to the future of cancer diagnostics and therapeutics.This symposium will familiarize the audience with the potential applications of nanoparticles in oncologic imaging and therapy using specific illustrative examples. The audience will be properly oriented by these illustrative examples to the multiple avenues for collaborative research amongst interdisciplinary teams of physicists, clinicians, engineers, chemists, and biologists in industry and academia.Learning Objectives: Understand the physical bases of gold nanoparticle applications for radiosensitization and x‐ray fluorescence imaging Understand the parameters that define gold nanoparticle‐mediated radiosensitization in biological systems Understand the potential of magnetic nanoparticle characterization of the microenvironment Understand the various strategies for radiolabeling of nanoparticles and their applications S.C. and S.K. acknowledge support from MD Anderson Cancer Center, NIH (R01CA155446 and P30CA16672) and DoD (W81XWH‐12‐1‐0198); J.W. acknowledges support from NIH (U54CA151662‐01); W.C. acknowledges support from the University of Wisconsin‐Madison, NIH (R01CA169365, P30CA014520, and T32CA009206), DoD (W81XWH‐11‐1‐0644 and W81XWH‐11‐1‐0648), and ACS (125246‐RSG‐13‐099‐01‐CCE).

WE‐G‐303‐00: Nanotechnology for Imaging and Therapy

Over the last decade, there has been a growing interest in applying nanotechnology to cancer detection, treatment, and treatment monitoring. Advances in nanotechnology have enabled the fabrication of nanoparticles from various materials with different shapes and sizes. Nanoparticles can be accumulated preferentially within tumors by either “passive targeting” through a phenomenon typically known as “enhanced permeability and retention” or “active targeting” in which nanoparticles are conjugated with antibodies or peptides directed against tumor and/or stromal markers. The tumor specificity of nanoparticles in conjunction with their unique physicochemical properties offers many novel strategies for cancer treatment and detection. For example, notable approaches in the radiation oncology setting include the use of gold nanoparticles for radiation response modulation of tumor or normal tissue and thermal ablation or hyperthermia treatment of tumors. Some of these approaches are currently being tested either on humans or on animals and, very likely, will become the clinical reality in the near future. Various computational and experimental techniques have also been applied to address unique research issues associated with nanoparticles and may become the standard tools for future investigations and clinical translations. Therefore, both clinicians and researchers may need to be properly educated about the basic principles as well as the promise of nanoparticle‐based applications with regard to the future of cancer diagnostics and therapeutics.This symposium will familiarize the audience with the potential applications of nanoparticles in oncologic imaging and therapy using specific illustrative examples. The audience will be properly oriented by these illustrative examples to the multiple avenues for collaborative research amongst interdisciplinary teams of physicists, clinicians, engineers, chemists, and biologists in industry and academia.Learning Objectives: Understand the physical bases of gold nanoparticle applications for radiosensitization and x‐ray fluorescence imaging Understand the parameters that define gold nanoparticle‐mediated radiosensitization in biological systems Understand the potential of magnetic nanoparticle characterization of the microenvironment Understand the various strategies for radiolabeling of nanoparticles and their applications S.C. and S.K. acknowledge support from MD Anderson Cancer Center, NIH (R01CA155446 and P30CA16672) and DoD (W81XWH‐12‐1‐0198); J.W. acknowledges support from NIH (U54CA151662‐01); W.C. acknowledges support from the University of Wisconsin‐Madison, NIH (R01CA169365, P30CA014520, and T32CA009206), DoD (W81XWH‐11‐1‐0644 and W81XWH‐11‐1‐0648), and ACS (125246‐RSG‐13‐099‐01‐CCE).

TU‐B‐210‐02: MRg HIFU ‐ Advanced Approaches for Ablation and Hyperthermia

MR guided focused ultrasound (MRgFUS), or alternatively high‐intensity focused ultrasound (MRgHIFU), is approved for thermal ablative treatment of uterine fibroids and pain palliation in bone metastases. Ablation of malignant tumors is under active investigation in sites such as breast, prostate, brain, liver, kidney, pancreas, and soft tissue. Hyperthermia therapy with MRgFUS is also feasible, and may be used in conjunction with radiotherapy and for local targeted drug delivery. MRI allows in situ target definition and provides continuous temperature monitoring and subsequent thermal dose mapping during HIFU. Although MRgHIFU can be very precise, treatment of mobile organs is challenging and advanced techniques are required because of artifacts in MR temperature mapping, the need for intercostal firing, and need for gated HIFU or tracking of the lesion in real time. The first invited talk, “MR guided Focused Ultrasound Treatment of Tumors in Bone and Soft Tissue”, will summarize the treatment protocol and review results from treatment of bone tumors. In addition, efforts to extend this technology to treat both benign and malignant soft tissue tumors of the extremities will be presented. The second invited talk, “MRI guided High Intensity Focused Ultrasound – Advanced Approaches for Ablation and Hyperthermia”, will provide an overview of techniques that are in or near clinical trials for thermal ablation and hyperthermia, with an emphasis of applications in abdominal organs and breast, including methods for MRTI and tracking targets in moving organs.Learning Objectives: Learn background on devices and techniques for MR guided HIFU for cancer therapy Understand issues and current status of clinical MRg HIFU Understand strategies for compensating for organ movement during MRgHIFU Understand strategies for strategies for delivering hyperthermia with MRgHIFU CM ‐ research collaboration with Philips

TU‐B‐210‐01: MRg HIFU ‐ Bone and Soft Tissue Tumor Ablation

MR guided focused ultrasound (MRgFUS), or alternatively high‐intensity focused ultrasound (MRgHIFU), is approved for thermal ablative treatment of uterine fibroids and pain palliation in bone metastases. Ablation of malignant tumors is under active investigation in sites such as breast, prostate, brain, liver, kidney, pancreas, and soft tissue. Hyperthermia therapy with MRgFUS is also feasible, and may be used in conjunction with radiotherapy and for local targeted drug delivery. MRI allows in situ target definition and provides continuous temperature monitoring and subsequent thermal dose mapping during HIFU. Although MRgHIFU can be very precise, treatment of mobile organs is challenging and advanced techniques are required because of artifacts in MR temperature mapping, the need for intercostal firing, and need for gated HIFU or tracking of the lesion in real time. The first invited talk, “MR guided Focused Ultrasound Treatment of Tumors in Bone and Soft Tissue”, will summarize the treatment protocol and review results from treatment of bone tumors. In addition, efforts to extend this technology to treat both benign and malignant soft tissue tumors of the extremities will be presented. The second invited talk, “MRI guided High Intensity Focused Ultrasound – Advanced Approaches for Ablation and Hyperthermia”, will provide an overview of techniques that are in or near clinical trials for thermal ablation and hyperthermia, with an emphasis of applications in abdominal organs and breast, including methods for MRTI and tracking targets in moving organs.Learning Objectives: Learn background on devices and techniques for MR guided HIFU for cancer therapy Understand issues and current status of clinical MRg HIFU Understand strategies for compensating for organ movement during MRgHIFU Understand strategies for strategies for delivering hyperthermia with MRgHIFU CM ‐ research collaboration with Philips

TU-B-210-00: MR-Guided Focused Ultrasound Therapy in Oncology

MR guided focused ultrasound (MRgFUS), or alternatively high-intensity focused ultrasound (MRgHIFU), is approved for thermal ablative treatment of uterine fibroids and pain palliation in bone metastases. Ablation of malignant tumors is under active investigation in sites such as breast, prostate, brain, liver, kidney, pancreas, and soft tissue. Hyperthermia therapy with MRgFUS is also feasible, and may be used in conjunction with radiotherapy and for local targeted drug delivery. MRI allows in situ target definition and provides continuous temperature monitoring and subsequent thermal dose mapping during HIFU. Although MRgHIFU can be very precise, treatment of mobile organs is challenging and advanced techniques are required because of artifacts in MR temperature mapping, the need for intercostal firing, and need for gated HIFU or tracking of the lesion in real time. The first invited talk, “MR guided Focused Ultrasound Treatment of Tumors in Bone and Soft Tissue”, will summarize the treatment protocol and review results from treatment of bone tumors. In addition, efforts to extend this technology to treat both benign and malignant soft tissue tumors of the extremities will be presented. The second invited talk, “MRI guided High Intensity Focused Ultrasound – Advanced Approaches for Ablation and Hyperthermia”, will provide an overview of techniques that are in or near clinical trials for thermal ablation and hyperthermia, with an emphasis of applications in abdominal organs and breast, including methods for MRTI and tracking targets in moving organs. Learning Objectives: 1. Learn background on devices and techniques for MR guided HIFU for cancer therapy 2. Understand issues and current status of clinical MRg HIFU 3. Understand strategies for compensating for organ movement during MRgHIFU 4. Understand strategies for strategies for delivering hyperthermia with MRgHIFU CM - research collaboration with Philips

The effect of radiofrequency thermal ablation method on nasal mucociliary activity in patients with inferior turbinate hypertrophy.

This study aims to investigate the effect of radiofrequency thermal ablation (RFTA) treatment on nasal mucociliary activity before and after treatment in inferior turbinate hypertrophy. Thirty-nine patients (21 males, 18 females; mean age 36.3±13.9 years; range 16 to 67 years) admitted to our clinic with complaint of nasal obstruction and diagnosed with stromal inferior turbinate hypertrophy were included in this study. Effect of RFTA treatment on nasal mucociliary activity was investigated by saccharine test before treatment and two months after treatment. Grade of nasal obstruction was evaluated by visual analog scale (VAS) before treatment and two months after treatment. Results were compared with paired t-test. Mean mucociliary activity times were 9.8±4.4 minutes before treatment and 9.6±4.1 minutes two months after treatment, and the difference between two tests was not statistically significant (p=0.3). Mean VAS scores for nasal obstruction were 6.5±1.2 before treatment and 3.8±1.0 two months after treatment, and the difference between two results was statistically significant (p=0.001). Difference between sexes in terms of saccharine transit time and VAS values before and after treatment was not statistically significant (p>0.05). It was detected that RFTA has no adverse effect on mucociliary activity in the treatment of inferior turbinate hypertrophy, and this method is notably effective in relieving the nasal obstruction caused by inferior turbinate hypertrophy.

Offline RF thermal ablation planning using CT/MRI scan data

In this paper, steady state temperature variations in the human brain due to different electrical and physical changes have been studied considering different thermal ablation treatment requirements using RF probe. Initially, a subject specific voxel-based electrical model has been constructed from Digital Imaging and Communication in Medicine (DICOM) formatted Computed Tomography (CT) or Magnetic Resonance (MR) based image stacks with different pixel characteristics using the Hounsfield unit extraction technique. This subject specific electrical model that consists of different dielectric constant and conductivity, considering different anatomical organs and tissues is simulated using commercially available finite integral technique (FIT) based EM simulation software CST Microwave Studio®. This study clearly shows the possibility of subject specific precise offline microwave thermal ablation treatment planning.

Echo decorrelation imaging for quantification of tissue structural changes during ultrasound ablation

Echo decorrelation imaging is a pulse-echo method that maps millisecond-scale changes in backscattered ultrasound signals, potentially providing real-time feedback during thermal ablation treatments. Decorrelation between echo signals from sequential image frames is spatially mapped and temporally averaged, resulting in images of cumulative, heat-induced tissue changes. Theoretical analysis indicates that the mapped echo decorrelation parameter is equivalent to a spatial decoherence spectrum of the tissue reflectivity, and also provides a method to compensate decorrelation artifacts caused by tissue motion and electronic noise. Results are presented from experiments employing 64-element linear arrays that perform bulk thermal ablation, focal ablation, and pulse-echo imaging using the same piezoelectric elements, ensuring co-registration of ablation and image planes. Decorrelation maps are shown to correlate with ablated tissue histology, including vital staining to map heat-induced cell death, for both ex vivo ablation of bovine liver tissue and in vivo ablation of rabbit liver with VX2 carcinoma. Receiver operating characteristic curve analysis shows that echo decorrelation predicts local ablation with greater success than integrated backscatter imaging. Using artifact-compensated echo decorrelation maps, heating-induced decoherence of tissue scattering media is assessed for ex vivo and in vivo ultrasound ablation by unfocused and focused beams.

A29 Session 8: Gastrointestinal Cryotherapeutic Indications : Endoscopic cryotherapy for Barrett’s esophagus and esophageal cancer

Endoscopic cryotherapy (Cryo) or local application of cryogen to the gastrointestinal mucosa is a thermal ablative treatment that has been used for Barrett’s esophagus (BE) and high grade dysplasia, as well as for palliative use in esophageal adenocarcinoma (EAC). Most of the existing data are related to this indication, but endoscopic cryotherapy has also successfully used for treatment of gastric antral vascular ectasia and radiation proctitis. Cryo using liquid nitrogen or compressed carbon dioxide or nitrogen gas is delivered via an endoscopic spray catheter resulting in tissue destruction without direct contact. Freezing occurs due to the Joules-Thompson effect. Data on the optimal dosimetry are limited, but a variable number of cycles of 8–20 s of freeze and thaw have been used. For Barrett’s esophagus, there are no randomized controlled trials. However, retrospective studies on the use of Cryo in patients with high grade dysplasia and/or early adenocarcinoma suggest great potential safety and efficacy for curative intent. Complete response rates of 68–100% have been reported. Complete response rates for eradiation of esophageal intestinal metaplasia (BE) are about 53–84%. These results are comparable to radiofrequency ablation, which is the reference standard for BE ablation. These provide a distinct advantage for Cryo over superficial forms of endoscopic ablation such as radiofrequency ablation or argon plasma coagulation. Adverse events have also been uncommon, mainly due to strictures (9%, all easily dilated), and very rare perforations during early studies. Cryo may also be a viable outpatient endoscopic treatment option for patients with obstructing tumors and cancers that recur after chemotherapy and/or radiation therapy. Compared to alternative endoscopic cancer palliative therapies for EAC such as photodynamic therapy (that results in extreme photosensitivity, greater pain and more frequent esophageal strictures) and esophageal stenting (which causes chest pain and does not treat the primary tumor), Cryo is an attractive viable palliative treatment option. One retrospective multicenter study of liquid nitrogen Cryo reported complete regression of BE HGD of 100%, luminal cancer in 75% with no serious adverse events and 2 year follow-up (Gossain et al., Gastrointest Endosc 2013). Finally, Cryo may also be considered for local treatment of high risk inoperable patients with BE adenocarcinomas in non-lifting nodular lesions, depressed and ulcerated lesions (Paris IIc and III class), or deep margin positive invasive EAC following endoscopic mucosal resection. Device development is ongoing, including improvements of existing devices and clinical trials on new devices such as a focal and circumferential cryotherapy balloon. Clinical trials are ongoing. Endoscopic cryotherapy has a great potential for mainstream clinical therapeutic use in early studies but more data are needed, particularly on optimal dosimetry, safety and cost-effectiveness compared with other existing therapies, long term outcomes, and quality of life.

Effect of radiofrequency thermal ablation treatment on nasal mucociliary clearance in patients with isolated inferior turbinate hypertrophy

This study aims to evaluate the effect of the radiofrequency thermal ablation on nasal mucociliary clearance in patients with isolated inferior concha hypertrophy. Thirty patients (10 females, 20 males; mean age 31.0±12.0 years; range 18 to 61 years) who were admitted to our clinic with a complaint of chronic nasal obstruction and diagnosed with isolated inferior concha submucosal hypertrophy between May 2009 and December 2009 were included. Radiofrequency thermal ablation was applied to the inferior concha at three separate points with 350 joule at 75 °C as a treatment. Nasal mucociliary clearance was evaluated through saccharin clearance test in pre- and postoperative (at eight weeks) period. The mean pre- and postoperative saccharin clearance tests were 565.4±253.9 sec and 558.7±257.7 sec, respectively. However, there was no significant difference in two measurements (p>0.05). Our study results show that radiofrequency thermal ablation application for the treatment of isolated inferior concha hypertrophy has no effect on nasal mucociliary clearance.

Functionalized gold nanorods for thermal ablation treatment of bladder cancer.

Nanomaterial-directed, photothermal ablation is a practical future approach for the treatment of early-stage bladder cancer. Using a new PEGylation technique with bi-functional nitrophenyl carbonate PEG (bi-NPC-PEG) that promotes uniform suspension of the nanomaterial in solution, we have shown that gold nanorods conjugated to an anti-EGFR antibody (nano-alphaEGFR) bind effectively to EGFR-expressing bladder cancer cells. The subsequent application of infrared light, specifically tuned to the plasmon resonance of the nanorods used in this work, allows for the specific heating of nano-alphaEGFR to the point of localized cellular death. Such an approach, administering nano-alphaEGFR intravesically via a urinary catheter and infrared light via a modified cystoscope, represents a novel, future clinical application of this technology, which avoids the problem of systemic exposure and clearance of nanoparticles from body.

Effect of thermal ablation on HSP70 expression in benign thyroid nodules

Objective To explore the changes of HSP70 expression after radiofrequency ablation of benign thyroid nodules and to discuss the potential relevance.Methods Ultrasound-guided radiofrequency ablation(RFA)was conducted for treating 50 solid thyroid nodules in 50 patients.Three different regions of interest(ROI),namely the central region,marginal region and transitional region, were set on each nodule for quantitative investigation of HSP70 expression by using immunohistochemistry method.Each ROI experienced histological sampling by using core-needle biopsy before and after RFA.HSP70 expression was compared for the same ROI before and after ablation and between different ROIs after ablation.Results HSP70 expression had no significant changes in the central and marginal regions before and after ablation in the 50 solid thyroid nodules,and the expression was significantly enhanced in the transitional region after ablation(P0.05).After ablation the expression of HSP70 in the transitional region was significantly higher than those in the central and marginal regions(P0.05),with no significant difference found between the latter two regions.Conclusion Increased expression of HSP70 in the transitional region might protect normal glandular tissue against heat damage during thermal ablation treatment of benign thyroid nodules.

Dynamics of tissue shrinkage during ablative temperature exposures

There is a lack of studies that examine the dynamics of heat-induced shrinkage of organ tissues. Clinical procedures such as radiofrequency ablation, microwave ablation or high-intensity focused ultrasound, use heat to treat diseases such as cancer and cardiac arrhythmia. When heat is applied to tissues, shrinkage occurs due to protein denaturation, dehydration and contraction of collagen at temperatures greater 50 °C. This is particularly relevant for image-guided procedures such as tumor ablation, where pre- and post-treatment images are compared and any changes in dimensions must be considered to avoid misinterpretations of the treatment outcome. We present data from ex vivo, isothermal shrinkage tests in porcine liver tissue, where axial changes in tissue length were recorded during 15 min of heating to temperatures between 60 and 95 °C. A mathematical model was developed to accurately describe the time and temperature-dependent shrinkage behavior. The shrinkage dynamics had the same characteristics independent of temperature; the estimated relative shrinkage, adjusted for time since death, after 15 min heating to temperatures of 60, 65, 75, 85 and 95 °C, was 12.3, 13.8, 16.6, 19.2 and 21.7%, respectively. Our results demonstrate the shrinkage dynamics of organ tissues, and suggest the importance of considering tissue shrinkage for thermal ablative treatments.

Temperature–density hysteresis in X-ray CT during HIFU thermal ablation: Heating and cooling phantom study

Purpose: This paper investigated the effects of thermal ablation treatment on imaged X-ray computed tomography (CT) Hounsfield units (HU), for the purpose of monitoring tissue denaturation and coagulation.Materials and methods: Eight phantoms of water, oil, and chicken serum albumin as well as 15 ex vivo tissue samples were heated by applying high intensity focused ultrasound (HIFU) for 10 to 29 min to obtain denaturation temperatures, (i.e. >50 °C). X-ray CT scanning was performed simultaneously during heating and post-ablation cooling stages, and the HU at the focal zone were registered. The temperature profile versus time was also monitored under similar conditions using a thermocouple probe. The results were plotted and correlated as curves of HU versus temperature.Results: In all specimens studied, HU values depicted an exponential curve as a function of temperature during the heating stage. However, linear behaviour was observed during the cool-down stage for both chicken serum albumin and ex vivo bovine liver. Thus, a hysteresis phenomenon occurred only when the thermal conditions induced irreversible changes in the sample with quantification demonstrating high correlation with the maximal temperature reached during treatment (R2 > 0.9) for the chicken serum albumin.Conclusions: Our results demonstrate a HU–temperature hysteresis phenomenon for HIFU ablation, which is detectible by X-ray CT. This hysteresis is related to the amount of heat induced into the tissue and could potentially indicate irreversible tissue damage. Accordingly, this measurable phenomenon can be utilised as a quantitative method for non-invasive monitoring of thermal ablation.

The state of the art of endothermal ablation

Complaints relating to reflux in the venous system can be addressed by conservative, surgical, or interventional treatment options. The aim of the treatment is to prevent complications and progression of venous disease and to improve patients' quality of life. Endovenous thermal ablation therapies have become the most frequently used type of therapy for saphenous varicose veins. The available endovenous thermal techniques are endovenous laser ablation, radiofrequency ablation, and endovenous steam ablation. In this review, the procedures, indications, and treatment parameters of the three endovenous thermal ablation treatments are discussed as well as their advantages and disadvantages.

Treatment with the vascular disruptive agent OXi4503 induces an immediate and widespread epithelial to mesenchymal transition in the surviving tumor

Epithelial to mesenchymal transition (EMT) is considered an important mechanism in tumor resistance to drug treatments; however, in vivo observation of this process has been limited. In this study we demonstrated an immediate and widespread EMT involving all surviving tumor cells following treatment of a mouse model of colorectal liver metastases with the vascular disruptive agent OXi4503. EMT was characterized by significant downregulation of E-cadherin, relocation and nuclear accumulation of β-catenin as well as significant upregulation of ZEB1 and vimentin. Concomitantly, significant temporal upregulation in hypoxia and the pro-angiogenic growth factors hypoxia-inducible factor 1-alpha, hepatocyte growth factor, vascular endothelial growth factor and transforming growth factor-beta were seen within the surviving tumor. The process of EMT was transient and by 5 days after treatment tumor cell reversion to epithelial morphology was evident. This reversal, termed mesenchymal to epithelial transition (MET) is a process implicated in the development of new metastases but has not been observed in vivo histologically. Similar EMT changes were observed in response to other antitumor treatments including chemotherapy, thermal ablation, and antiangiogenic treatments in our mouse colorectal metastasis model and in a murine orthotopic breast cancer model after OXi4503 treatment. These results suggest that EMT may be an early mechanism adopted by tumors in response to injury and hypoxic stress, such that inhibition of EMT in combination with other therapies could play a significant role in future cancer therapy.Vascular disruptive treatments effectively destroy over 90% of solid tumors with minimal effects on host tissues but a viable rim of cells persists in the tumor periphery that leads to recurrence. An immediate and widespread epithelial to mesenchymal transition (EMT) occurs within the viable rim after treatment that may be responsible for this resistance to treatment. Targeting EMT in combination with vascular disruptive agents or other therapies in the clinic may improve treatment outcomes.