Surrounding Lung Tissue Research Articles

Functional Heterogeneity of CD4+ Tumor-Infiltrating Lymphocytes With a Resident Memory Phenotype in NSCLC.

Resident memory T cells (TRM) inhabit peripheral tissues and are critical for protection against localized infections. Recently, it has become evident that CD103+ TRM are not only important in combating secondary infections, but also for the elimination of tumor cells. In several solid cancers, intratumoral CD103+CD8+ tumor infiltrating lymphocytes (TILs), with TRM properties, are a positive prognostic marker. To better understand the role of TRM in tumors, we performed a detailed characterization of CD8+ and CD4+ TIL phenotype and functional properties in non-small cell lung cancer (NSCLC). Frequencies of CD8+ and CD4+ T cell infiltrates in tumors were comparable, but we observed a sharp contrast in TRM ratios compared to surrounding lung tissue. The majority of both CD4+ and CD8+ TILs expressed CD69 and a subset also expressed CD103, both hallmarks of TRM. While CD103+CD8+ T cells were enriched in tumors, CD103+CD4+ T cell frequencies were decreased compared to surrounding lung tissue. Furthermore, CD103+CD4+ and CD103+CD8+ TILs showed multiple characteristics of TRM, such as elevated expression of CXCR6 and CD49a, and decreased expression of T-bet and Eomes. In line with the immunomodulatory role of the tumor microenvironment, CD8+ and CD4+ TILs expressed high levels of inhibitory receptors 2B4, CTLA-4, and PD-1, with the highest levels found on CD103+ TILs. Strikingly, CD103+CD4+ TILs were the most potent producers of TNF-α and IFN-γ, while other TIL subsets lacked such cytokine production. Whereas, CD103+CD4+PD-1low TILs produced the most effector cytokines, CD103+CD4+PD-1++ and CD69+CD4+PD-1++ TILs produced CXCL13. Furthermore, a large proportion of TILs expressed co-stimulatory receptors CD27 and CD28, unlike lung TRM, suggesting a less differentiated phenotype. Agonistic triggering of these receptors improved cytokine production of CD103+CD4+ and CD69+CD8+ TILs. Our findings thus provide a rationale to target CD103+CD4+ TILs and add co-stimulation to current therapies to improve the efficacy of immunotherapies and cancer vaccines.

Respiratory-resolved MR-based attenuation correction for motion-compensated cardiac PET-MR

Respiratory motion during cardiac PET acquisitions can cause image blurring and erroneous uptake quantification. In particular the misalignment of attenuation correction (AC) maps and PET emission data can lead to severe quantification errors, because the AC value of the heart is five times higher than of the surrounding lung tissue. Standard PET-MR approaches assume accurate alignment between breathhold MR-based AC maps and free-breathing PET emission data but cannot necessarily ensure it. Here we propose a 75 s free-breathing MR-acquisition, which provides respiratory-resolved AC maps (ACDyn) and non-rigid respiratory motion information. This approach ensures accurate AC for free-breathing PET data and the motion information can be utilized to reduce image blurring caused by respiratory motion. 3D multi-echo MR data was acquired during a 75 s free-breathing scan in six patients. Both a respiratory-resolved dynamic AC map (ACDyn) and a non-rigid respiratory motion field are provided by the MR scan. ACDyn yielded AC values for different breathing phases ensuring accurate AC for each respiratory phase of the free-breathing PET data. In addition, motion-corrected image reconstruction (MCIR) of MR and PET data was used to minimize breathing artefacts. Motion amplitudes in the left ventricle were 8.2 ± 2.9 mm with a dominant motion direction along the anterior-anterolateral and inferior-inferoseptal axis of the heart. The proposed ACDyn-MCIR technique led to significant signal recovery of PET tracer uptake by 24 ± 5% (p < 0.05). The maximum improvement was observed in patients with large misalignment between standard breathhold MR-based AC maps and PET emission data. PET image resolution was improved by 20 ± 12% (p < 0.05). We have presented an efficient MR-scan, which ensures accurate motion information and AC values to improve PET quantification for cardiac PET-MR scans. The short scan time of 75 s makes this free-breathing acquisition easy to integrate into standard clinical PET-MR protocols.

Positron emission tomography-computed tomography and 4-hydroxynonenal-histidine immunohistochemistry reveal differential onset of lipid peroxidation in primary lung cancer and in pulmonary metastasis of remote malignancies

The Aim of the study was to reveal if PET-CT analysis of primary and of secondary lung cancer could be related to the onset of lipid peroxidation in cancer and in surrounding non-malignant lung tissue. MethodsNineteen patients with primary lung cancer and seventeen patients with pulmonary metastasis were involved in the study. Their lungs were analyzed by PET-CT scanning before radical surgical removal of the cancer. Specific immunohistochemistry for the major bioactive marker of lipid peroxidation, 4-hydroxynonenal (HNE), was done for the malignant and surrounding non-malignant lung tissue using genuine monoclonal antibody specific for the HNE-histidine adducts. ResultsBoth the intensity of the PET-CT analysis and the HNE-immunohistochemistry were in correlation with the size of the tumors analyzed, while primary lung carcinomas were larger than the metastatic tumors. The intensity of the HNE-immunohistochemistry in the surrounding lung tissue was more pronounced in the metastatic than in the primary tumors, but it was negatively correlated with the cancer volume determined by PET-CT. The appearance of HNE was more pronounced in non-malignant surrounding tissue than in cancer or stromal cells, both in case of primary and metastatic tumors. ConclusionsBoth PET-CT and HNE-immunohistochemistry reflect the size of the malignant tissue. However, lipid peroxidation of non-malignant lung tissue in the vicinity of cancer is more pronounced in metastatic than in primary malignancies and might represent the mechanism of defense against cancer, as was recently revealed also in case of human liver cancer.

Within the next five years, adaptive hypofractionation will become the most common form of radiotherapy.

Within the next five years, adaptive hypofractionation will become the most common form of radiotherapy.

176-08: Break of circular catheter stuck in a right-inferior pulmonary vein during cryoballon pulmonary vein isolation

Case Report: We report a fifty-year-old male with paroxysmal atrial fibrillation presenting with EHRA III symptoms who underwent pulmonary vein isolation (PVI). The PVI was planned with a 28mm cryoballon under deep sedation. After uncomplicated transseptal puncture, angiography of the left atrium (LA) was done showing four independent pulmonary veins (PV). Heparin was given to maintain an activated clotting time of >300s. Following successful left PV isolation, the circular diagnostic catheter (CDC) was advanced in the right inferior PV (RIPV) and one successful freeze was delivered. After thawing of the cryoballon, it turned out not to be possible to remove the CDC from the RIPV. The fluoroscopy showed that the CDC was stuck in a small branch of the RIPV. While pulling the CDC the patient started to cough. The surrounding lung tissues seemed to be tightened and dragged together with the CDC. While turning the CDC, the shaft of the CDC broke close to the holder of the steerable sheath. With use of the remaining shaft, we further tried to remove the CDC from the PV, however, the CDC was again completely torn from the base of the circular part in the branch of RIPV. We then removed the proximal shaft and isolated the superior right PV with one freeze using a newly unpacked CDC. Final LA angiography demonstrated neither obstructions of major PVs nor exit of contrast agent out of LA, although the circular part of the CDC remained in the small branch of RIPV. After the procedure the patient showed no complaints such as cough, dyspnea or other symptoms. A pericardial effusion was also excluded. Discussion: Due to the tying in a small branch of the RIPV the CDC was stuck and we could not recover the catheter anymore. No practical way to resolve this situation has been described yet. Further catheter pulling was not an option due to the risk of a fatal bleeding because the surrounding lung tissue was tied. Another option could be an open-heart surgery. As the remaining part of the catheter did not move at all, we decided to leave the remaining circular part after a consultation with heart surgery unit. After a follow-up of one month the patient showed neither AF event nor clinical symptoms such as cough, dyspnea. We here reported a break of the CDC shaft during PVI with cryoballoon, which has been not yet reported.

Role of Arrival Time Difference Between Lesions and Lung Tissue on Contrast-Enhanced Sonography in the Differential Diagnosis of Subpleural Pulmonary Lesions.

The purpose of this study was to explore the diagnostic value of the arrival time difference between lesions and surrounding lung tissue on contrast-enhanced sonography of subpleural pulmonary lesions. A total of 110 patients with subpleural pulmonary lesions who underwent both conventional and contrast-enhanced sonography and had a definite diagnosis were enrolled. After contrast agent injection, the arrival times in the lesion, lung, and chest wall were recorded. The arrival time differences between various tissues were also calculated. Statistical analysis showed a significant difference in the lesion arrival time, the arrival time difference between the lesion and lung, and the arrival time difference between the chest wall and lesion (all P < .001) for benign and malignant lesions. Receiver operating characteristic curve analysis revealed that the optimal diagnostic criterion was the arrival time difference between the lesion and lung, and that the best cutoff point was 2.5 seconds (later arrival signified malignancy). This new diagnostic criterion showed superior diagnostic accuracy (97.1%) compared to conventional diagnostic criteria. The individualized diagnostic method based on an arrival time comparison using contrast-enhanced sonography had high diagnostic accuracy (97.1%) with good feasibility and could provide useful diagnostic information for subpleural pulmonary lesions.

Improved pulmonary nodule classification utilizing quantitative lung parenchyma features.

Current computer-aided diagnosis (CAD) models for determining pulmonary nodule malignancy characterize nodule shape, density, and border in computed tomography (CT) data. Analyzing the lung parenchyma surrounding the nodule has been minimally explored. We hypothesize that improved nodule classification is achievable by including features quantified from the surrounding lung tissue. To explore this hypothesis, we have developed expanded quantitative CT feature extraction techniques, including volumetric Laws texture energy measures for the parenchyma and nodule, border descriptors using ray-casting and rubber-band straightening, histogram features characterizing densities, and global lung measurements. Using stepwise forward selection and leave-one-case-out cross-validation, a neural network was used for classification. When applied to 50 nodules (22 malignant and 28 benign) from high-resolution CT scans, 52 features (8 nodule, 39 parenchymal, and 5 global) were statistically significant. Nodule-only features yielded an area under the ROC curve of 0.918 (including nodule size) and 0.872 (excluding nodule size). Performance was improved through inclusion of parenchymal (0.938) and global features (0.932). These results show a trend toward increased performance when the parenchyma is included, coupled with the large number of significant parenchymal features that support our hypothesis: the pulmonary parenchyma is influenced differentially by malignant versus benign nodules, assisting CAD-based nodule characterizations.

MO‐AB‐BRA‐02: A Novel Scatter Imaging Modality for Real‐Time Image Guidance During Lung SBRT

Purpose:A novel scatter imaging modality is developed and its feasibility for image‐guided radiation therapy (IGRT) during stereotactic body radiation therapy (SBRT) for lung cancer patients is assessed using analytic and Monte Carlo models as well as experimental testing.Methods:During treatment, incident radiation interacts and scatters from within the patient. The presented methodology forms an image of patient anatomy from the scattered radiation for real‐time localization of the treatment target. A radiographic flat panel‐based pinhole camera provides spatial information regarding the origin of detected scattered radiation. An analytical model is developed, which provides a mathematical formalism for describing the scatter imaging system. Experimental scatter images are acquired by irradiating an object using a Varian TrueBeam accelerator. The differentiation between tissue types is investigated by imaging simple objects of known compositions (water, lung, and cortical bone equivalent). A lung tumor phantom, simulating materials and geometry encountered during lung SBRT treatments, is fabricated and imaged to investigate image quality for various quantities of delivered radiation. Monte Carlo N‐Particle (MCNP) code is used for validation and testing by simulating scatter image formation using the experimental pinhole camera setup.Results:Analytical calculations, MCNP simulations, and experimental results when imaging the water, lung, and cortical bone equivalent objects show close agreement, thus validating the proposed models and demonstrating that scatter imaging differentiates these materials well. Lung tumor phantom images have sufficient contrast‐to‐noise ratio (CNR) to clearly distinguish tumor from surrounding lung tissue. CNR=4.1 and CNR=29.1 for 10MU and 5000MU images (equivalent to 0.5 and 250 second images), respectively.Conclusion:Lung SBRT provides favorable treatment outcomes, but depends on accurate target localization. A comprehensive approach, employing multiple simulation techniques and experiments, is taken to demonstrate the feasibility of a novel scatter imaging modality for the necessary real‐time image guidance.

SU-F-207-13: Comparison of Four Dimensional Computed Tomography (4D CT) Versus Breath Hold Images to Determine Pulmonary Nodule Elasticity

Purpose: Elasticity may distinguish malignant from benign pulmonary nodules. To compare determining of malignant pulmonary nodule (MPN) elasticity from four dimensional computed tomography (4D CT) images versus inhale/exhale breath-hold CT images. Methods: We analyzed phase 00 and 50 of 4D CT and deep inhale and natural exhale of breath-hold CT images of 30 MPN treated with stereotactic ablative radiotherapy (SABR). The radius of the smallest MPN was 0.3 cm while the biggest one was 2.1 cm. An intensity based deformable image registration (DIR) workflow was applied to the 4D CT and breath-hold images to determine the volumes of the MPNs and a 1 cm ring of surrounding lung tissue (ring) in each state. Next, an elasticity parameter was derived by calculating the ratio of the volume changes of MPN (exhale:inhale or phase50:phase00) to that of a 1 cm ring of lung tissue surrounding the MPN. The proposed formulation of elasticity enables us to compare volume changes of two different MPN in two different locations of lung. Results: The calculated volume ratio of MPNs from 4D CT (phase50:phase00) and breath-hold images (exhale:inhale) was 1.00±0.23 and 0.95±0.11, respectively. It shows the stiffness of MPN and comparably bigger volume changes of MPN in breath-hold images because of the deeper degree of inhalation. The calculated elasticity of MPNs from 4D CT and breath-hold images was 1.12±0.22 and 1.23±0.26, respectively. For five patients who have had two MPN in their lung, calculated elasticity of tumor A and tumor B follows same trend in both 4D CT and breath-hold images. Conclusion: We showed that 4D CT and breath-hold images are comparable in the ability to calculate the elasticity of MPN. This study has been supported by Department of Defense LCRP 2011 #W81XWH-12-1-0286.

Noninvasive pulmonary nodule elastometry by CT and deformable image registration

Background and purposeTo develop a noninvasive method for determining malignant pulmonary nodule (MPN) elasticity, and compare it against expert dual-observer manual contouring. Methods and materialsWe analyzed breath-hold images at extreme tidal volumes of 23 patients with 30 MPN treated with stereotactic ablative radiotherapy. Deformable image registration (DIR) was applied to the breath-hold images to determine the volumes of the MPNs and a ring of surrounding lung tissue (ring) in each state. MPNs were also manually delineated on deep inhale and exhale images by two observers. Volumes were compared between observers and DIR by Dice similarity. Elasticity was defined as the absolute value of the volume ratio of the MPN minus one normalized to that of the ring. ResultsFor all 30 tumors the Dice coefficient was 0.79±0.07 and 0.79±0.06 between DIR with observers 1 and 2, respectively, close to the inter-observer Dice value, 0.81±0.1. The elasticity of MPNs was 1.24±0.26, demonstrating that volume change of the MPN was less than that of the surrounding lung. ConclusionWe developed a noninvasive CT elastometry method based on DIR that measures the elasticity of biopsy-proven MPN. Our future direction would be to develop this method to distinguish malignant from benign nodules.

M2 polarization enhances silica nanoparticle uptake by macrophages

While silica nanoparticles have enabled numerous industrial and medical applications, their toxicological safety requires further evaluation. Macrophages are the major cell population responsible for nanoparticle clearance in vivo. The prevailing macrophage phenotype largely depends on the local immune status of the host. Whereas M1-polarized macrophages are considered as pro-inflammatory macrophages involved in host defense, M2 macrophages exhibit anti-inflammatory and wound-healing properties, but also promote tumor growth. We employed different models of M1 and M2 polarization: granulocyte-macrophage colony-stimulating factor/lipopolysaccharide (LPS)/interferon (IFN)-γ was used to generate primary human M1 cells and macrophage colony-stimulating factor (M-CSF)/interleukin (IL)-10 to differentiate M2 monocyte-derived macrophages (MDM). PMA-differentiated THP-1 cells were polarized towards an M1 type by LPS/IFN-γ and towards M2 by IL-10. Uptake of fluorescent silica nanoparticles (Ø26 and 41 nm) and microparticles (Ø1.75 μm) was quantified. At the concentration used (50 μg/ml), silica nanoparticles did not influence cell viability as assessed by MTT assay. Nanoparticle uptake was enhanced in M2-polarized primary human MDM compared with M1 cells, as shown by flow cytometric and microscopic approaches. In contrast, the uptake of microparticles did not differ between M1 and M2 phenotypes. M2 polarization was also associated with increased nanoparticle uptake in the macrophage-like THP-1 cell line. In accordance, in vivo polarized M2-like primary human tumor-associated macrophages obtained from lung tumors took up more nanoparticles than M1-like alveolar macrophages isolated from the surrounding lung tissue. In summary, our data indicate that the M2 polarization of macrophages promotes nanoparticle internalization. Therefore, the phenotypical differences between macrophage subsets should be taken into consideration in future investigations on nanosafety, but might also open up therapeutic perspectives allowing to specifically target M2 polarized macrophages.

Selection of Sensitive Methylation Markers for the Detection of Non-small Cell Lung Cancer

Introduction: While early-stage lung cancer is curable by surgical resection, most patients are diagnosed with advanced- stage disease. Annual low-dose computed tomography screening decreases lung cancer mortality, however effective biomarkers to address the high false positive rate and to better define high risk individuals are lacking. This study was designed to identify potential DNA methylation markers for the detection of non-small cell lung cancer, the most common type of lung cancer. Methods: 152 candidate methylation genes were first investigated in lung cancer cell lines and a pilot set of lung tissues. Five promising methylated genes, DMRTA, HOXA9, ZIC4, HOXA7, and SIX3, were selected and further validated in 150 non-small cell lung cancers and 142 tumor-free surrounding lung tissues using the quantitative methylation-specific PCR. Results: Methylation levels of DMRTA2, HOXA9, ZIC4, HOXA7, and SIX3 were significantly higher in tumors compared to tumor-free surrounding lung tissues (P 0.05). Conclusion: We identified a group of highly sensitive and specific methylation markers in non-small cell lung cancer. These markers are potential valuable candidates to improve the performance of lung cancer screening.

Non-lobar atelectasis generates inflammation and structural alveolar injury in the surrounding healthy tissue during mechanical ventilation.

IntroductionWhen alveoli collapse the traction forces exerted on their walls by adjacent expanded units may increase and concentrate. These forces may promote its re-expansion at the expense of potentially injurious stresses at the interface between the collapsed and the expanded units. We developed an experimental model to test the hypothesis that a local non-lobar atelectasis can act as a stress concentrator, contributing to inflammation and structural alveolar injury in the surrounding healthy lung tissue during mechanical ventilation.MethodsA total of 35 rats were anesthetized, paralyzed and mechanically ventilated. Atelectasis was induced by bronchial blocking: after five minutes of stabilization and pre-oxygenation with FIO2 = 1.0, a silicon cylinder blocker was wedged in the terminal bronchial tree. Afterwards, the animals were randomized between two groups: 1) Tidal volume (VT) = 10 ml/kg and positive end-expiratory pressure (PEEP) = 3 cmH2O (VT10/PEEP3); and 2) VT = 20 ml/kg and PEEP = 0 cmH2O (VT20/zero end-expiratory pressure (ZEEP)). The animals were then ventilated during 180 minutes. Three series of experiments were performed: histological (n = 12); tissue cytokines (n = 12); and micro-computed tomography (microCT; n = 2). An additional six, non-ventilated, healthy animals were used as controls.ResultsAtelectasis was successfully induced in the basal region of the lung of 26 out of 29 animals. The microCT of two animals revealed that the volume of the atelectasis was 0.12 and 0.21 cm3. There were more alveolar disruption and neutrophilic infiltration in the peri-atelectasis region than the corresponding contralateral lung (control) in both groups. Edema was higher in the peri-atelectasis region than the corresponding contralateral lung (control) in the VT20/ZEEP than VT10/PEEP3 group. The volume-to-surface ratio was higher in the peri-atelectasis region than the corresponding contralateral lung (control) in both groups. We did not find statistical difference in tissue interleukin-1β and cytokine-induced neutrophil chemoattractant-1 between regions.ConclusionsThe present findings suggest that a local non-lobar atelectasis acts as a stress concentrator, generating structural alveolar injury and inflammation in the surrounding lung tissue.

SBRT for Lung Cancer Appears to Provide Superior Local Control to Wedge Resection: Is This Due to the Therapeutic Effects of Low-Dose Peripheral Radiation?

Stereotactic body radiation therapy (SBRT) appears to yield extraordinarily high local control rates, >80-90%, for non-small cell lung cancer (NSCLC); sometimes exceeding the local control rates reported with wedge resection alone. A possible advantage of SBRT over wedge is the potential therapeutic benefit of the “low-dose” radiation delivered to tissues beyond the target. We herein assess the approximate physical doses and equivalent radiobiologic doses (adjusting for both fraction size and overall treatment time) to surrounding lung tissue of SBRT-targeted lesions.

Dosimetric comparison of flattened and unflattened beams for stereotactic ablative radiotherapy of stage I non‐small cell lung cancer

To compare contribution and accuracy of delivery for two flattening filter free (FFF) beams of the nominal energy 6 and 10 MV and a 6 MV flattened beam for early stage lung cancer. For each of 11 patients with stage I nonsmall cell lung cancer three volumetric modulated arc therapy plans were prepared utilizing a 6 MV flattened photon beam (X6FF) and two nonflattened beams of nominal energy 6 and 10 MV (X6FFF, X10FFF). Optimization constraints were set to produce dose distributions that meet the criteria of the RTOG-0915 protocol. The radiation schedule used for plan comparison in all patients was 50 Gy in five fractions. Dosimetric parameters of planning target volume (PTV) and organs-at-risk and delivery times were assessed and compared. All plans were subject to verification using Delta(4) unit (Scandidos, Sweden) and absolutely calibrated gafchromic films in a thorax phantom. All plans had a qualitatively comparable outcome. Obtained dose distributions were conformal (CI < 1.17) and exhibited a steep dose fall-off outside the PTV. The ratio of monitor units for FFF versus FF plans in the authors' study ranged from 0.95 to 1.21 and from 0.93 to 1.25 for X6FFF/X6FF and X10FFF/X6FF comparisons, respectively. The ratio systematically increased with increasing size of the PTV (up to +25% for 150 cm(3) PTV). Yet the integral dose to healthy tissue did not follow this trend. Comparison of cumulative dose volume histograms for a patient's body showed that X6FFF plans exhibit improved conformity and reduced the volume of tissue that received more than 50% of the prescription dose. Parameters related to dose gradient showed statistically significant improvement. CI50%, CI60%, CI80%, and CI100% were on average reduced by 4.6% (p < 0.001), 4.6% (p = 0.002), 3.1% (p = 0.002), and 1.2% (p = 0.039), respectively. Gradient measure was on average reduced by 4.2% (p < 0.001). Due to dose reduction in the surrounding lung tissue, the V20 Gy and V12.5 Gy were reduced by 5.5% (p = 0.002) and 4.5% (p < 0.001). These dosimetric improvements in the fall-off were not observed for the X10FFF plans. Differences in sparing of normal tissues were not found to be statistically significant for either of the two FFF beams. Mean beam-on times were 111 s (2SD = 11 s) for X10FFF, 128 s (2SD = 19 s) for X6FFF, and X6FF plans required on average 269 s (2SD = 71 s). While the mean dose rate was 1555 ± 264 and 1368 ± 63 MU/min, for X10FFF and X6FFF, plans using the conventional X6FF were delivered with the constant maximum dose rate of 600 MU/min. Verification of all plans showed acceptable and comparable results for all plans in homogeneous as well as heterogeneous phantoms. Mean GS (3%, 2 mm) using the Delta(4) phantom were 98.9% (2SD = 3.2%), 99.2% (2SD = 2.3%), and 99.2% (2SD = 2.3%) for X6FFF, X6FF, and X10FFF modalities. Verification using a thorax phantom showed GS > 98% in all cases. The use of FFF beams for stereotactic radiation therapy of nonsmall cell lung cancer patients yielded dose distributions qualitatively comparable to flattened beams and significantly reduced treatment delivery time. Utilizing the X6FFF beam improved conformity of dose distribution. On the other hand, X10FFF beam offered a slight improvement in treatment efficiency, and lower skin and peripheral dose. All effects were relatively small.

Laser Resection of Lung Tissue: Heat Accumulation from Adjacent Laser Application and How to Cool It Down

Heat accumulation might induce thermal damage of the surrounding lung tissue, especially when multiple lesions are resected in one session. The present study aimed to investigate whether heat accumulates in the immediate vicinity of the resection surface and leads to thermal damage of the lung parenchyma, and what is the most effective cooling strategy in this situation. In normothermic perfused paracardial swine lobes (n = 6), four punctiform laser lesions forming a square were created. Each lesion was lasered at a power of 100 W for 5 seconds. Two test conditions with square sides of either 1.0 or 0.5 cm were compared. Temperatures were recorded immediately after completing the laser procedure in the square center and in the corners using a thermal camera and continued during the cooling process at 10-second intervals until normothermia (37°C). We examined two cooling methods: rinsing with ice-cold (4°C) Ringer solution during the laser procedure (group B, n = 6) or submerging the lung in ice-cold water for 5 seconds immediately after laser application (group C, n = 6). In the control group A (n = 6), there was no cooling. In the 0.5 cm squares, mean temperature in the center immediately after laser application was 103.17 ± 8.56°C, significantly higher than in the corners (76.39 ± 2.87°C, p < 0.05). Normothermia in the quadrant corners was reached after 81 ± 14 and after 108 ± 29 seconds in the centers. Tissue in the square center revealed histological signs of thermic cell damage. In the 1.0 cm squares, mean temperature in the center was 64 ± 5°C, and in the corners was 77 ± 3.1°C (p < 0.05). Normothermia was regained after 93 ± 22 seconds in the center and 120 ± 21 seconds in the corners. Histological examination in the 1.0-quadrant centers revealed no signs of thermic cell damage. Submerging the lobe into ice-cold water lowered the temperature rapidly to under 40°C, and normothermia was regained after 75 ± 1.3 seconds. Laser application to the lung parenchyma causes considerable heat accumulation in closely related lesions. To prevent such cell damage, a distance of at least 1.0 cm between laser targets should be maintained. If no topical cooling method applied, sufficient time for spontaneous tissue cooling before additional laser application should be provided. The most effective cooling strategy against heat accumulation is submerging in ice-cold water for at least 5 seconds.

Comparison of local tissue damage: monopolar cutter versus Nd:YAG laser for lung parenchyma resection. An experimental study

Lung metastases are non-anatomically resected while sparing as much parenchyma as possible. For this purpose, a few surgeons use the Nd:YAG Laser LIMAX 120, whereas the majority of surgeons use a monopolar cutter like the MAXIUM. The aim of this experimental study was to investigate which instrument causes less lung-tissue damage at the same power output. These experiments were conducted on left lungs (n = 6) taken from freshly slaughtered pigs. The laser and the monopolar cutter were fixed in a hydraulic mover. The laser was focused at a distance of 3 cm to the lung tissue and the monopolar cutter was fixed in pressure-free contact with the lung surface. Both instruments were manoeuvred at a speed of 5, 10 and 20 mm/s in a straight line at an output of 100 watts over the lung surface. The lung lesions that ensued were then examined macro- and microscopically. The same procedures were repeated at a distance of 1 cm creating parallel lesions in order to analyse the lung tissue in between the lesions for thermal damage. In addition, two implanted capsules in the lung tissue simulating a lung nodule were resected with either the laser or the monopolar cutter. The resection surfaces were then examined by magnetic resonance imaging and histology for tissue damage. Finally, we created a 2-cm wide mark on the lung surface to test the resection capacity of both instruments within 1 min. The laser created sharply delineated lesions with a vaporization and coagulation zone without thermal damage of the surrounding lung tissue. With lowering the working speed, each zone was extended. At a working speed of 10 mm/s, the mean vaporization depth using the laser was 1.74 ± 0.1 mm and the mean coagulation depth was 1.55 ± 0.09 mm. At the same working speed, the monopolar cutter demonstrated a greater cutting effect (mean vaporization depth 2.7 ± 0.11 mm; P < 0.001) without leaving much coagulation on the resection surface (mean coagulation depth 1.25 ± 0.1 mm; P = 0.002). In contrast to the laser, the monopolar cutter caused thermal damage of the adjacent lung tissue. The adjacent tissue injury was detected in histological examination as well as in the MRI findings. Adjacent lung tissue after lung metastasectomy using the monopolar cutter was hyper-intensive in T2-weighted MR imaging, indicating a severe tissue damage. No significant changes in signal intensity were observed in T2-weighted imaging of the adjacent lung tissue after using the laser for lung resection. One minute of laser applied at a 100-watt output penetrated a lung surface area of 3.8 ± 0.4 cm(2) compared with 4.8 ± 0.6 cm(2) of surface after application of the monopolar cutter (P = 0.001). The monopolar cutter possesses indeed a greater cutting capacity than the laser, but it also causes more adjacent tissue injury. Thus, laser resection might be preferred for lung metastasectomy.

Differential effect of soy isoflavones in enhancing high intensity radiotherapy and protecting lung tissue in a pre-clinical model of lung carcinoma

BackgroundRadiotherapy of locally-advanced non-small cell lung cancer is limited by radiation-induced pneumonitis and fibrosis. We have further investigated the role of soy isoflavones to improve the effect of a high intensity radiation and reduce lung damage in a pre-clinical lung tumor model. MethodsHuman A549 NSCLC cells were injected i.v. in nude mice to generate a large tumor burden in the lungs. Mice were treated with lung irradiation at 10Gy and with oral soy. The therapy effect on the tumor cells and surrounding lung tissue was analyzed on lung sections stained with H&E, Ki-67 and Masson’s Trichrome. Pneumonitis and vascular damage were evaluated by measurements of alveolar septa and immunofluorescent staining of vessel walls. ResultsCombined soy and radiation caused a significantly stronger inhibition of tumor progression compared to each modality alone in contrast to large invasive tumor nodules seen in control mice. At the same time, soy reduced radiation injury in lung tissue by decreasing pneumonitis, fibrosis and protecting alveolar septa, bronchioles and vessels. ConclusionsThese studies demonstrate a differential effect of soy isoflavones on augmenting tumor destruction induced by radiation while radioprotecting the normal lung tissue and support using soy to alleviate radiotoxicity in lung cancer.

SU-E-J-132: Lung Dose Reduction From Patient Specific 4D Motion Based Non-Uniform Dose Prescription in Lung IMRT Treatment

Purpose: Motion of the tumor target in lung can be significant in patients. Traditionally lung dose is uniformly prescribed to the entire Internal Tumor Volume (ITV) with certain setup margin. Such uniform dose prescription may deliver quite high dose to the normal tissue surrounding the target volume due to tumor motion. This study explores patient specific motion based non‐uniform dose prescription that is to deliver prescription dose to the target while maximizing the sparing of the surrounding normal tissue. Methods: Patient 4D CT images were collected during simulation. CT phases were deformably registered. The spatial tracks of the tumor and surrounding tissue voxels were extracted from the transform matrix. The voxel dose to the tumor target and the surrounding tissue was evaluated at each phase and then summed together. Simulated Annealing algorithm was used to search for the spatial dose prescription distribution that delivers sufficient tumor voxel dose while minimizing the surrounding normal tissue dose. Results: Simple phantom and patients studies were included. The optimization process generally converged within 60 seconds to obtain a solution for non‐uniform dose prescription. The Result has shown a reduction in the adjacent lung tissue as great as 18% while maintaining the tumor dose. Conclusion: This study proposed a methodology for a non‐uniform dose prescription that would deliver sufficient dose to the moving lung tumor target while maximizing the sparing of the surrounding lung tissue. The beam delivery and the interplay effect are being further studied.

Abstract LB-358: Soy improves radiotherapy for lung tumors and mitigates radiation-induced injury to lung tissue.

Abstract Radiotherapy of locally-advanced non-small cell lung cancer (NSCLC) is limited by pneumonitis and fibrosis caused by radiation-induced injury to normal lung tissue. We have investigated the effect of a high thoracic dose of radiation combined with soy isoflavones in a pre-clinical model of orthotopic A549 human lung carcinoma xenografts in nude mice. Mice bearing established lung tumors (&amp;gt;300µm) were pretreated with soy for 3 days starting day 15 after A549 cell injection, and then received 10 Gy irradiation administered to the whole lung. Soy treatment, given orally at 1mg/day (50mg/kg) was continued for 5 days per week for 4 more weeks, then lungs were perfused with formalin and processed for histology. The effect of the therapy on the tumor cells, the surrounding tumor microenvironment and lung tissue structures was further analyzed using novel immunostaining and quantitative techniques. Compared to large invasive lung tumor nodules (up to 1-2 x 106 µm2) in untreated mice, the combined therapy caused a significant inhibition of tumor progression in lungs resulting in few residual small tumor nodules (0.02-0.07 x 106 µm2, p&amp;lt;0.05) with a low index of proliferation (mean of 16 positive nuclei for Ki-67 compared to 147 in control tumors, p&amp;lt;0.001). Pneumonitis was evaluated by morphometric measurements of the thickness of alveolar septa on H&amp;E stained lung tissue sections. Soy isoflavones reduced the extent of pneumonitis induced by radiation resulting in 30% of the lung tissue with thickened septa compared to 45% observed in lungs treated with radiation only. Fibrosis staining using Masson's Trichrome revealed that radiation caused a dramatic increase in collagen fibers supporting the vessel and bronchiole walls and this effect was mitigated by soy isoflavones. Triple immunofluorescent staining of lung vessel walls was performed on lung tissue sections using antibodies specific to endothelial cells (anti-CD31), pericytes (anti-SMA) and collagen (anti-collagen IV). This technique revealed that soy isoflavones combined with radiation decreased the fraction of vessels with damaged basement membrane to 25% down from 42% in radiation-alone treated lungs. Thus, these studies demonstrate a differential effect of soy isoflavones on augmenting tumor destruction induced by radiation while acting as radioprotectors for the surrounding lung tissue. Soy isoflavones reduced pneumonitis and fibrosis, and preserved the integrity of lung structures including alveolar septa, bronchioles and vessels, probably by mitigation of the inflammatory response induced by radiation. Complementing cancer radiotherapy with soy isoflavones has the potential to improve its effectiveness on the tumor target and reduce dose-limiting radiotoxicity to the normal lung and could be applied in the treatment of advanced stage NSCLC. Citation Format: Gilda Gali Hillman, Vinita Singh-Gupta, David J. Hoogstra, Lisa Abernathy, Joseph Rakowski, Christopher Yunker, Fazlul H. Sarkar, Andre A. Konski, Fulvio Lonardo, Michael C. Joiner. Soy improves radiotherapy for lung tumors and mitigates radiation-induced injury to lung tissue. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-358. doi:10.1158/1538-7445.AM2013-LB-358