Laser Ablation Of Tumors Research Articles

EXTH-30. GOLD NANOSTARS OBVIATE LIMITATIONS TO LASER INTERSTITIAL THERMAL THERAPY (LITT) AND ENHANCE THE POST-LITT IMMUNE RESPONSE

Abstract Laser interstitial thermal therapy (LITT) is a minimally-invasive technique for the treatment of intracranial tumors that uses a stereotactically-guided laser and real-time magnetic resonance imaging (MRI) to monitor ablation progress. Previous applications of gold nanostars (GNS) in laser ablation of tumors have studied extracranial tumors only and utilized externally administered near infrared radiation that cannot penetrate the cranial compartment. Herein, we present a novel platform for employing GNS in intracranial tumors. We developed non-toxic GNS that exhibit maximum photothermal effects at the 1064 nm laser wavelength used in the FDA-approved clinical Neuroblate® LITT system. Monte Carlo simulations demonstrate that our GNS can accelerate and focus thermal energy distributions. Using ex vivo tumor phantom models, we found that GNS-infused phantoms demonstrate more rapid heating and improved spatial conformation of thermal energy, with neighboring material exposed to lower temperatures than controls. In our intracranial CT-2A glioma model, we quantified accumulation of radiolabeled GNS in tumor tissue via PET/CT. As further validation of tumor-selective GNS accumulation, we used two-photon luminescence to show that GNS selectively accumulate and are retained in intracranial tumors at 24 and 72 hours post-injection. We then utilized our in vivo heterotopic CT-2A model to assess the capacity of systemically-delivered GNS to augment laser ablation; we were able to achieve higher ablation temperatures and more efficient temperature ramping with LITT+GNS. Finally, we explored the potential of LITT+GNS to synergize with immunotherapy to further enhance the post-ablation immune response and found that combination therapy resulted in improved tumor control and immunologic memory that was protective against tumor rechallenge. These results support the ability of GNS to optimize LITT for the treatment of intracranial tumors by improving efficiency and safety, and illustrate the potential of this platform to synergize with immunotherapy.

A case of duodenal perforation and pancreatic bleeding after flexible ureteroscopy for right renal pelvis UTUC

Upper tract urothelial carcinoma (UTUC) can be managed by flexible ureteroscopy (f-URS) and tumor laser ablation if kidney-sparing surgery is possible. This procedure can be affected by minor to serious complications, including life-threatening sepsis, ureteral strictures, and ureteral and renal pelvis injuries. The case of a 53-year-old man with history of high grade right renal pelvis and bladder tumor who undergone multiple endoscopic treatments and has already refused radical surgery is reported. F-URS and laser ablation with Thulium: YAG laser for UTUC recurrence of the right renal pelvis was performed, but the procedure was stopped due to significant bleeding which impaired vision. Postoperatively, the patient developed hematemesis and hemodynamic instability due to duodenal lesion and active bleeding documented at CT scan. An emergency exploratory laparotomy was performed to drain hemoperitoneum, repair duodenal lesion and concurrent radical right nephroureterectomy was carried out. A second surgery was necessary for repairing duodenal fistula. After 1 week the patient presented again with recurrent hematemesis and hemorrhagic shock. He underwent angiography and selective embolization of the duodenal branch of superior mesenteric artery and as well as branches of gastroduodenal artery successfully and the patient recovered with no other complications. This is the first case of duodenal perforation and pancreatic bleeding due to flexible ureteroscopy and laser ablation of right renal pelvis urothelial carcinoma.

SYST-17 GOLD NANOSTARS ENHANCE THE EFFICACY AND SAFETY OF LASER INTERSTITIAL THERAPY FOR THE TREATMENT OF INTRACRANIAL TUMORS

Abstract Laser interstitial thermal therapy (LITT) is a minimally-invasive technique for the treatment of intracranial tumors that uses a stereotactically-guided laser for ablation. Magnetic resonance thermal imaging is used to monitor ablation progress by measuring the cumulative heat energy exposure in both the tumor and the surrounding tissue to calculate thermal damage thresholds.Previous applications of GNS in laser ablation of tumors have studied extracranial tumors only and utilized externally administered near infrared radiation that cannot penetrate the cranial compartment. Herein, we present a novel platform for employing GNS in intracranial tumors. We developed GNS that exhibit maximum photothermal effects at the 1064 nm laser wavelength used in the FDA-approved clinical Neuroblate® LITT system. Monte Carlo simulations demonstrate that our GNS can accelerate and focus thermal energy distributions. Using ex vivo tumor phantom models, GNS-infused phantoms demonstrate more rapid heating, expanded ablation zones, and improved margin conformation, with surrounding areas exposed to lower temperatures than controls. In in vivo intracranial tumor models, we show that GNS selectively accumulate and are retained in CT2A glioma and B16F0 melanoma tumors at 24 and 72 hours post-injection. Using our in vivo heterotopic CT2A model, we demonstrate that systemically-delivered GNS dramatically augment laser ablation, with higher temperatures achieved in the tumor and more efficient temperature ramping. These results support the ability of GNS to optimize LITT for the treatment of intracranial tumors by improving the efficiency and safety of this platform.

Management of Upper Tract Urothelial Carcinoma

We review the epidemiology, risk factors, diagnosis, and treatment of upper tract urothelial carcinoma (UTUC), with a distinction between the different risk groups. Endoscopic treatment with laser ablation of tumors has an evolving role in treating low-grade UTUC including select large and multifocal tumors, along with complementary topical chemotherapeutic treatment that can reach difficult intrarenal locations. Template lymphadenectomy is recommended in patients undergoing nephroureterectomy. A recent randomized control trial showed benefit of adjuvant chemotherapy after radical nephroureterectomy for locally advanced disease. Advances in immunologic therapy have shown promise in treating metastatic UTUC, and immunologic-based therapies have been incorporated into treatment regimens. Notable progress has been made in both the surgical and medical treatment arms for UTUC, thus extending the reach of nephron-sparing therapy for those with localized disease and increasing overall survival for those with locally advanced disease.

Intelligent optical diagnosis and treatment system for automated image-guided laser ablation of tumors.

For tumor resections near critical structures, accurate identification of tumor boundaries and maximum removal are the keys to improve surgical outcome and patient survival rate, especially in neurosurgery. In this paper, we propose an intelligent optical diagnosis and treatment system for tumor removal, with automated lesion localization and laser ablation. The proposed system contains a laser ablation module, an optical coherence tomography (OCT) unit, and a robotic arm along with a stereo camera. The robotic arm can move the OCT sample arm and the laser ablation front-end to the suspected lesion area. The corresponding diagnosis and treatment procedures include computer-aided lesion segmentation using OCT, automated ablation planning, and laser control. The ablation process is controlled by a deflectable mirror, and a non-common-path ablation planning algorithm based on the transformation from lesion positions to mirror deflection angles is presented. Phantom and animal experiments are carried out for system verification. The robot could reach the planned position with high precision, which is approximately 1.16mm. Tissue classification with OCT images achieves 91.7% accuracy. The error of OCT-guided automated laser ablation is approximately 0.74mm. Experiments on mouse brain tumors show that the proposed system is capable of clearing lesions efficiently and precisely. We also conducted an ex vivo porcine brain experiment to verify the whole process of the system. An intelligent optical diagnosis and treatment system is proposed for tumor removal. Experimental results show that the proposed system and method are promising for precise and intelligent theranostics. Compared to conventional cancer diagnosis and treatment, the proposed system allows for automated operations monitored in real-time, with higher precision and efficiency.

Awake Laser Ablation for Patients With Tumors in Eloquent Brain Areas: Operative Technique and Case Series

BackgroundMagnetic resonance imaging (MRI)-guided laser interstitial thermal therapy (LITT) is a minimally invasive treatment modality that has been gaining traction in neuro-oncology. Laser ablation is a particularly appealing treatment option when eloquent neurologic function at the tumor location precludes conventional surgical excision. Although typically performed under general anesthesia, LITT in awake patients may help monitor and preserve critical neurologic functions.ObjectiveTo describe intraoperative workflow and clinical outcomes in patients undergoing awake laser ablation of brain tumors.MethodsWe present a cohort of six patients with tumors located in eloquent brain areas that were treated with awake LITT and report three different workflow paradigms involving diagnostic or intraoperative MRI. In all cases, we used NeuroBlate® (Monteris Medical, Plymouth, MN) fiberoptic laser probes for stereotactic laser ablation of tumors. The neurologic status of patients was intermittently assessed every few minutes during the ablation.ResultsThe mean preoperative tumor volume that was targeted was 12.09 ± 3.20 cm3, and the estimated ablation volume was 12.06 ± 2.75 cm3. Performing the procedure in awake patients allowed us close monitoring of neurologic function intraoperatively. There were no surgical complications. The length of stay was one day for all patients except one. Three patients experienced acute or delayed worsening of pre-existing neurologic deficits that responded to corticosteroids.ConclusionWe propose that awake LITT is a safe approach when tumors in eloquent brain areas are considered for laser ablation.

Temperature monitoring of tumor hyperthermal treatments with optical fibers: comparison of distributed and quasi-distributed techniques

Abstract Optical fiber based sensors capable of measuring temperature distribution over a given length are particularly attractive in the biomedical field, especially in the case of real-time monitoring of minimally invasive hyperthermal treatments of tumors, such as laser ablation, given their intrinsic multiplexing along a single fiber span and the unique properties of optical fibers in terms of flexibility, size and electromagnetic compatibility. The paper compares two sensing approaches: one is based on an array of Bragg gratings inscribed in the core of a single-mode fiber, the other detects Rayleigh backscattering from an unmodified single-mode fiber using coherent optical frequency domain reflectometry. Following an introduction, which describes the most distinctive features of the two approaches, the paper presents three comparative experiments, each devised to highlight a peculiar aspect of the sensors. In the first experiment the sensors are exposed to various constant temperature distributions to evaluate the uniformity of the readings along the fiber length. In the second experiment, a known temperature profile is generated through an ad hoc setup to evaluate the actual capability of the two approaches to reconstruct the temperature distribution. Finally, in the third experiment the two sensors are employed in a simulated tumor laser ablation procedure to measure the temperature distribution in the irradiated area. Both sensors provide results whose error, mainly due to cross sensitivity between temperature and strain, is acceptable for the considered biomedical application.

Performance of Thulium Super Pulse Laser for Endoscopic Ablation of Urothelial Cell Carcinoma: Results of the First Cases in North America

Abstract Introduction: Tumor laser ablation (LTA) is a valuable option for treatment of urothelial cell carcinoma (UCC) in patients who are not amenable to nephroureterectomy. Recent in vitro studi...

In vivo optoacoustic monitoring of percutaneous laser ablation of tumors in a murine breast cancer model

Laser ablation (LA) is a promising approach for minimally invasive cancer treatments. Its in vivo applicability is often impeded by the lack of efficient monitoring tools that can help to minimize collateral tissue damage and aid in determining the optimal treatment end-points. We have devised a new, to the best of our knowledge, hybrid LA approach combining simultaneous volumetric optoacoustic (OA) imaging to monitor the lesion progression accurately in real time and 3D. Time-lapse imaging of laser ablation of solid tumors was performed in a murine breast cancer model in vivo by irradiation of subcutaneous tumors with a 100 mJ short-pulsed (${\sim}{5}\;{\rm ns}$∼5ns) laser operating at 1064 nm and 100 Hz pulse repetition frequency. Local changes in the OA signal intensity ascribed to structural alterations in the tumor vasculature were clearly observed, while the OA volumetric projections recorded in vivo appeared to correlate with cross sections of the excised tumors.

Initial experience of flexible ureteroscopy combined with thulium laser for the treatment of upper urinary tract urothelial carcinoma

Objective To summarize the initial experience of flexible ureteroscopy combined with thulium laser for the treatment of high-risk upper urinary tract urothelial carcinoma (UTUC) in patients with solitary kidney or renal insufficiency. Methods A retrospective analysis was performed in 5 cases of UTUC with solitary kidney or renal insufficiency treated via flexible ureteroscopy combined with thulium laser from May 2016 to November 2018. Patients consisted of 4 cases of left side tumor, 1 case of right side tumor, with median age of 73 years old(ranging 53-87 years old). Among the 5 cases, 3 were solitary kidney with renal pelvis tumors, 2 cases were renal insufficiency accompanied with proximal ureter or renal pelvis tumor. All the patients had tumors large than 2 cm in diameter. The creatine in 3 cases with solitary kidney was 102, 128, 143μmol/L, respectively. The creatine in 2 cases with renal insufficiency was 281, 179μmol/L, respectively. Variable hydronephrosis was noticed in all paients. The cytological examination could reveal tumor cells in all cases. During the operation, part of tumor tissues were resected for pathological examination and the remaining visible tumor tissue was all ablated and vaporized. As there was no obvious residual tumor tissue, double J stent was retained. Patients were regularly reexamined after surgery. Results Of the 5 cases, 4 patients were successfully performed, while intraoperative bleeding occurred in 1 case. The operation was suspended after indwelling double J stent. Then, the renal artery interventional embolism was performed after ineffective conservative treatment, and the bleeding was well controlled. One month later, the patient was treated with thulium laser tumor ablation and vaporizaiton under flexible ureteroscopy again. The pathology of all cases was high-grade invasive urinary epithelial carcinoma. Patients were followed up with regular imaging and endoscopic examination. The median follow-up period was 19 (4-26) months, during which 4 cases had local recurrence, one patient died of non-tumor factors. No recurrence of urothelial carcinoma occurred in the bladder during follow-up, the overall recurrence rate was 80%, and the median recurrence time was 6 (1-24) months. Patients with recurrence was treated with thulium laser tumor ablation and vaporizaiton under flexible ureteroscopy again. Conclusions Flexible ureteroscopy combined with thulium laser is an alternative treatment for high-risk upper urinary tract urothelial carcinoma in patients with solitary kidney or renal insufficiency, while with high tumor recurrence rate. Therefore, a stringent imaging and endoscopic follow-up should carry out postoperatively. Key words: Ureteroscopy; Flexible ureteroscope; Thulium laser; Upper urinary tract urothelial carcinoma

Preoperative Magnetic Resonance Imaging Based Predictive Modeling of Brain Tumor Laser Ablation

Abstract INTRODUCTION Laser interstitial thermal therapy (LITT) yields precise lesions under magnetic resonance imaging (MRI) thermometry guidance and is revolutionizing brain tumor management. However, one limitation is the inability to preoperatively predict how tumors will respond to thermal energy. Our study assessed whether preoperative variables correlated with intraoperative LITT ablation dynamics were capable of predicting how ablations progressed. METHODS Pixels indicating irreversible damage were quantified as a function of time for 101 brain tumor patients treated with LITT. Ablation dynamics were determined using pixel counts modeled with first-order dynamics and related to independent preoperative variables using stepwise regression. The resulting models were evaluated for predictive accuracy using leave-one-out cross-validation analysis. RESULTS Total pixels ablated is larger for LITT performed at a high laser power and for a long duration and for lesions with a low T1 GAD signal. The rate of pixel increase is elevated with high laser power and for lesions with a low T2 signal and prior radiotherapy. Pixel counts are well modeled with first-order dynamics. Scale factor (C) is positively related to perfusion, laser power, and T2 signal and negatively related to T1 signal. Time constant (t) is positively related to T2 signal and perfusion. Tshift is negatively related to T2 signal and laser power. Pathology did not impact ablation dynamics, although the presence of radiation necrosis resulted in faster and larger ablations. A predictive model based on the independent variables accounts for 77% of the variance in ablation pixel counts. CONCLUSION Preoperative MRI features correlate with brain tumor LITT ablation dynamics. Predictive models based on these features may eventually be used to guide the planning and delivery of LITT.

Predictive modeling of brain tumor laser ablation dynamics.

Laser interstitial thermal therapy (LITT) is a novel MR thermometry-guided thermoablative tool revolutionizing the clinical management of brain tumors. A limitation of LITT is our inability to estimate a priori how tissues will respond to thermal energy, which hinders treatment planning and delivery. The aim of this study was to determine whether brain tumor LITT ablation dynamics may be predicted by features of the preoperative MRI and the relevance of these data, if any, to the recurrence of metastases after LITT. Intraoperative thermal damage estimate (TDE) map pixels representative of irreversible damage were retrospectively quantified relative to ablation onset for 101 LITT procedures. Raw TDE pixel counts and TDE pixel counts modelled with first order dynamics were related to eleven independent variables derived from the preoperative MRI, demographics, laser settings, and tumor pathology. Stepwise regression analysis generated predictive models of LITT dynamics, and leave-one-out cross validation evaluated the accuracy of these models at predicting TDE pixel counts solely from the independent variables. Using a deformable atlas, TDE maps were co-registered to the immediate post-ablation MRI, allowing comparison of predicted and actual ablation sizes. Brain tumor TDE pixel counts modelled with first order dynamics, but not raw pixel counts, are correlated with the independent variables. Independent variables showing strong relations to the TDE pixel measures include T1 gadolinium and T2 signal, perfusion, and laser power. Associations with tissue histopathology are minimal. Leave-one-out analysis demonstrates that predictive models using these independent variables account for 77% of the variance observed in TDE pixel counts. Analysis of metastases treated revealed a trend towards the over-estimation of LITT effects by TDE maps during rapid ablations, which was associated with tumor recurrence. Features of the preoperative MRI are predictive of LITT ablation dynamics and could eventually be used to improve the clinical efficacy with which LITT is delivered to brain tumors.

Tunable fabrication of new theranostic Fe3O4-black TiO2 nanocomposites: dual wavelength stimulated synergistic imaging-guided phototherapy in cancer.

The development of a simplified theranostic system with high-efficiency for multifunctional imaging-guided photodynamic therapy/photothermal therapy (PDT/PTT) is a great challenge. Therefore, a versatile fabrication strategy was introduced to design new Fe3O4-black TiO2 nanocomposites (Fe-Ti NCs). The Fe-Ti NCs exhibit an intense broad light absorption, high photothermal conversion efficiency, inherited phototherapy, and favorable magnetic resonance imaging (MRI) properties. The in vitro results demonstrate synergistic PTT and PDT capability of Fe-Ti NCs under 808 nm irradiation at low concentration and power density. Fe-Ti NCs also show superior phototherapy performance (PTT/PDT) under 671 nm laser irradiation. The confocal microscopy analysis demonstrates reactive oxygen species (ROS)-mediated synergistic phototherapy. Hematological and histological analysis confirms no evident toxicity of Fe-Ti NCs. The in vivo photoinduced tumor ablation capability of Fe-Ti NCs was assessed and monitored, and a rapid increase in temperature (60 ± 2 °C) after being exposed to 808 nm laser at 0.7 W cm-2 for 5 min was observed. Then, the same change in temperature is observed under 671 nm laser at 0.5 W cm-2. Thus, in vitro and in vivo dual-wavelength laser tumor ablation ability of Fe-Ti NCs verified excellent synergistic phototherapy efficacy against tumors. Moreover, Fe-Ti NCs exhibit superparamagnetic behavior, high magnetization value (48 emu g-1), good r2 relaxivity value (38.2 mM-1 s-1), and excellent T2 imaging capability to monitor therapeutic performance.

PD65-04 MR/US FUSION GUIDED ULTRA-FOCAL GOLD NANOPARTICLE DIRECTED LASER ABLATION OF PROSTATE TUMORS: RESULTS IN THE FIRST 11 PATIENTS (PHASE I/II TRIAL)

You have accessJournal of UrologyProstate Cancer: Basic Research & Pathophysiology IV1 Apr 2018PD65-04 MR/US FUSION GUIDED ULTRA-FOCAL GOLD NANOPARTICLE DIRECTED LASER ABLATION OF PROSTATE TUMORS: RESULTS IN THE FIRST 11 PATIENTS (PHASE I/II TRIAL) Harry Anastos, Jared Winoker, Pratik Shukla, Shivaram Cumarasamy, John Sfakianos, Michael Carrick, Bodhi Rastinehad, Cynthia Knauer, Bachir Taouli, Sara Lewis, Jon Schwartz, and Ardeshir Rastinehad Harry AnastosHarry Anastos More articles by this author , Jared WinokerJared Winoker More articles by this author , Pratik ShuklaPratik Shukla More articles by this author , Shivaram CumarasamyShivaram Cumarasamy More articles by this author , John SfakianosJohn Sfakianos More articles by this author , Michael CarrickMichael Carrick More articles by this author , Bodhi RastinehadBodhi Rastinehad More articles by this author , Cynthia KnauerCynthia Knauer More articles by this author , Bachir TaouliBachir Taouli More articles by this author , Sara LewisSara Lewis More articles by this author , Jon SchwartzJon Schwartz More articles by this author , and Ardeshir RastinehadArdeshir Rastinehad More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2018.02.2988AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Gold Nanoparticles (GNP) mediated laser ablation has been shown to be biocompatible and safe for the treatment of focal cancer. Herein, we report the first 11 cases in the world using GNP-directed focal laser ablation of prostate tumors using ultrasound (US) and MR/US fusion technology (NCT NCT02680535). METHODS All patients were diagnosed with Gleason 7 or less prostate cancer with biopsy proven MR visible lesions and no disease other than appreciated on the MRI. Patients underwent ultra-focal laser ablation of the tumors using GNP with MR/US fusion guidance. Following infusion of intravenous GNP on Day 0, trans-perineal laser catheters were placed into the prostate lesions for GNP excitation/tumor ablation under MR/US fusion guidance using an electromagnetic-tracked MR/US fusion device (UroNav, Invivo Gainesville FL). At 48 hours post-ablation, the patient is imaged, followed by re-imaging and MR/US fusion guided biopsy (FBx) at 3 months. All patient demographics, clinical variables, and complications were recorded. RESULTS To date, 11 patients (mean age: 69.6 yrs; range 58-79 yrs) have been enrolled in the trial. All patients were diagnosed with Gleason < 7. All patients had a solitary lesion with mean tumor volume 0.73 mL (range 0.6-1.87 cc). A single patient did not tolerate the cold IV infusion of the gold nano particles and was not able to undergo ablation the following day. 8 of 10 patients have completed the 3 month follow-up targeted biopsy as primary endpoint. Mean pre-treatment PSA was 7.84 ng/mL (range 5.5-12.3 ng/mL). Mean post-treatment PSA was 3.9 ng/mL (range 1.5-6.1 ng/mL; 50% reduction). Five out of eight patients (62.5%) did not have any cancer detected on follow up biopsy. Only 1 out of 8 patients had clinically significant cancer as per Delphi consensus criteria (Gleason score >6 or cancer > 3mm at Gleason score 6). CONCLUSIONS Recent trends toward less invasive image guided therapies have been seen as investigators pursue focal targeted therapies. This report is the first in-man demonstration of MR/US guided ultra-focal laser ablation of prostate tumors using GNP. © 2018FiguresReferencesRelatedDetails Volume 199Issue 4SApril 2018Page: e1226 Advertisement Copyright & Permissions© 2018MetricsAuthor Information Harry Anastos More articles by this author Jared Winoker More articles by this author Pratik Shukla More articles by this author Shivaram Cumarasamy More articles by this author John Sfakianos More articles by this author Michael Carrick More articles by this author Bodhi Rastinehad More articles by this author Cynthia Knauer More articles by this author Bachir Taouli More articles by this author Sara Lewis More articles by this author Jon Schwartz More articles by this author Ardeshir Rastinehad More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

A Fiber Optic Probe for Tumor Laser Ablation With Integrated Temperature Measurement Capability

This paper presents the characterization results of a new all-optical applicator for improved tumor laser ablation treatments that features customized irradiation pattern and built-in temperature sensors. The probe exploits a double cladding optical fiber to integrate some Bragg gratings acting as temperature sensing elements in the core while guiding the high power beam used for the ablation in the inner cladding. The assessment of the probe behavior has been conducted in two steps: First, with an agar gel phantom to characterize the irradiation pattern and to validate the Bragg grating based measurement setup in comparison with a thermographic camera; then, simulating actual treatments using an ex vivo animal liver.

Confocal Laser Endomicroscopy in the Management of Endoscopically Treated Upper Urinary Tract Transitional Cell Carcinoma: Preliminary Data.

To describe our initial experience with confocal laser endomicroscopy (CLE) for the evaluation and treatment of patients with upper urinary tract transitional cell carcinoma (UUT-TCC). Preliminary data were analyzed from 11 patients with suspicion of UUT-TCC scheduled for flexible ureteroscopy (f-URS) and consensual holmium-YAG laser tumor ablation. CLE was performed before endoscopic biopsy and laser photoablation of the suspected lesion using a 3F-diameter flexible probe UroFlex™ B (Cellvizio® system; Mauna Kea Technologies, Paris, France), which allows to obtain microscopic resolution imaging (3.5 μm), with a field of view of 325 μm and a depth of tissue imaging of 40 to 70 μm. Video sequences were analyzed offline and thereafter compared with histopathologic findings. CLE technique was feasible and showed good quality imaging in all patients. Overall, the Cellvizio system provided reliable images of healthy urothelium when the probe was pointed toward normal tissue, showing umbrella cells on the surface and vessels in the lamina propria. Moreover, CLE displayed the characteristic features of high-density cellular aggregates and fibrovascular stalks in four patients with pathologically confirmed low-grade UUT-TCC. In the patient with pathologically confirmed high-grade UUT-TCC, more distorted microarchitecture and tortuous vessels were clearly recognized with CLE. These preliminary data showed the feasibility of CLE technique when applied to the diagnosis of UUT-TCC. Further clinical studies are required to confirm CLE accuracy in distinguishing healthy urothelial tissue from malignant lesions, thus helping clinicians in targeting ureteroscopic biopsy and improving the conservative management of UUT-TCC patients.

Photodynamic therapy in esophageal cancer

A B S T R A C T Historically, photodynamic therapy was an additional mechanism, along with external beam irradiation or brachytherapy, Nd:YAG laser tumor ablation or esophageal stent placement and to a lesser extent, chemotherapy, used to reestablish esophageal continuity in patients with esophageal malignancy who could not undergo resective surgery by virtue of infirmity or tumor stage. However, it has been virtually abandoned for this indication by most practitioners for over a decade. More recently, it has been used in the West to eradicate high-grade dysplasia and superficial malignancies arising in Barrett’s esophagus, although its expense, limited availability, and side effect profile make widespread use unlikely, particularly given the widespread availability of other effective techniques. The latter include endoscopic submucosal resection, endoscopic submucosal dissection, radiofrequency ablation, and cryotherapy. This review highlights the historical use of photodynamic therapy in the treatment of esophageal malignancy and potential roles for its application in the future.

Liver tumor laser ablation – increase in the subacute ablation lesion volume detected with post procedural MRI

The use of image-guided thermoablative methods in liver tumor treatment has expanded rapidly due to encouraging results and advanced imaging. However, little is known about the treatment-induced tissue response and effects on imaging findings during the subacute post procedural period. To study the development of subacute ablation zone volume with magnetic resonance imaging (MRI) after laser-mediated liver tumor thermal therapy. In all, 16 laser ablations were performed on 16 liver tumors resulting in 16 ablation zones in 11 consecutive patients. A low-field 0.23 T C-arm MRI scanner was used for imaging and procedural guidance. Repeated dynamic contrast-enhanced T1, contrast-enhanced T1 FSE, and T2 FSE studies of liver were performed at 0 and 72 h after the procedure. Ablation zone volumes were registered from the acquired image data. MRI scans showed a significant increase of ablation volume in all imaging sequences obtained at 72 h after the initial therapy. After laser ablation, there is a progressive perfusion decrease in the ablation site leading to an increase in the ablation volume. Post procedural baseline MRI at 72 h from the treatment provides more precise information about the ablation result than can be obtained with immediate post procedural MRI.

Ophthalmic Vasculature Alterations Following Systemic Chemotherapy and Periocular Carboplatin Treatment of Advanced Retinoblastoma

The purpose of this study was to report significant alterations in orbital vasculature following combined systemic chemoreduction/laser ablation and periocular carboplatin treatment and to discuss treatment implications in two cases of advanced retinoblastoma. Assessment of orbital and ophthalmic vasculature was done following nine cycles of systemic chemotherapy. Intra-arterial chemotherapy was provided 6 months following completion of systemic chemoreduction, when the tumor was clearly active and progressive. Orbital angiography of both eyes, performed prior to the intra-arterial melphalan injection, documented sclerosis of the ophthalmic artery vasculature with delayed transit time, decreased choroidal blush, and anomalous vessels in the eye receiving periocular carboplatin injections. The orbital vasculature in the contralateral eye was not affected. Orbital and ophthalmic vascular alterations may occur with the use of combined systemic chemotherapy and periocular carboplatin. Systemic chemotherapy and focal transpupillary laser tumor ablation, alone, did not appear to impact the orbital and ophthalmic vascular supply. Impaired vascular supply may have significant influence on the impact of the efficacy of standard and future experimental therapeutic options.

MP-19.01: The use of KTP laser tumor ablation for treatment of bladder transitional cell carcinoma (initial results)

MP-19.01: The use of KTP laser tumor ablation for treatment of bladder transitional cell carcinoma (initial results)