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At least 1,063 records · Page 59

Multicenter Phase 2 Study of Cisplatin and 5-Fluorouracil With Concurrent Radiation Therapy as an Organ Preservation Approach in Patients With Squamous Cell Carcinoma of the Cervical Esophagus

Purpose: To clarify, in a multicenter, single-arm, phase 2 study (UMIN Clinical Trials Registry no. UMIN000001439), the clinical profile of chemoradiotherapy (CRT) for cervical esophageal cancer. Patients and Methods: Patients with operable cervical esophageal cancer, excluding candidates for endoscopic resection, were enrolled. Protocol treatment consisted of CRT and adjuvant chemotherapy (CT). First, patients received concurrent CRT with 5-fluorouracil (5-FU) plus cisplatin (CDDP). Chemotherapy consisted of 5-FU at 700 mg/m{sup 2} intravenous on days 1 to 4 and CDDP at 70 mg/m{sup 2} intravenous on day 1, repeated every 4 weeks for 2 cycles. Radiation therapy consisted of 60 Gy in 30 fractions. After completion of CRT, 2 additional cycles of CT with 5-FU (800 mg/m{sup 2}, days 1-5) and CDDP (80 mg/m{sup 2}, day 1) were repeated at a 4-week interval. The primary endpoint was 3-year overall survival. Results: Thirty patients were enrolled across 8 institutions in Japan, consisting of 26 men and 4 women with a median age of 64.5 years (range, 50-75 years). No grade 4 hematologic toxicity was seen in the CRT phase, and 1 grade 4 thrombocytopenia was seen in the CT phase. Grade 3 nonhematologic acute toxicities in the CRT phase were nausea (10%), mucositis (13.3%), and dysphagia (13.3%). No treatment-related death in either phase occurred. Overall complete response rate was 73%, and 3-year overall and laryngectomy-free survival were 66.5% and 52.5%, respectively. Regarding T4 disease, 3-year overall and laryngectomy-free survival were 58.3% and 38.5%, respectively. Conclusions: This study, the first prospective study for cervical esophageal cancer, showed that CRT has sufficient efficacy and safety for use as an alternative to surgery for these patients.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Quality indexes based on water measurements for low and medium energy x-ray beams: A theoretical study with PENELOPE

Purpose : To study the use of quality indexes based on ratios of absorbed doses in water at two different depths to characterize x-ray beams of low and medium energies. Methods : A total of 55 x-ray beam spectra were generated with the codes XCOMP5R and SPEKCALC and used as input of a series of Monte Carlo simulations performed with PENELOPE, in which the percentage depth doses in water and thek{sub Q,Q{sub 0}} factors, defined in the TRS-398 protocol, were determined for each beam. Some of these calculations were performed by simulating the ionization chamber PTW 30010. Results : The authors found that the relation betweenk{sub Q,Q{sub 0}} and the ratios of absorbed doses at two depths is almost linear. A set of ratios statistically compatible with that showing the best fit has been determined. Conclusions : The results of this study point out which of these ratios of absorbed doses in water could be used to better characterize x-ray beams of low and medium energies.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Standard Operating Protocol for Ion-Exchange Capacity of Anion Exchange Membranes

Ion-exchange capacity (IEC) is the measure of a material’s capability to displace ions formerly incorporated within its structure. IEC is a key feature of anion-exchange membranes (AEM), as it determines the AEM’s ability to conduct the ions required to sustain the electrochemical reactions where they are utilized. As an intrinsic property, measuring the IEC accurately is essential to study AEMs and understand their performance within devices. In this method article, a facile and accurate standard operating procedure (SOP) to measure the IEC of AEMs is proposed. When compared to conventional acid-base back-titration or Mohr titration, the proposed method combines the fast reaction between silver and halide ions and the accuracy of the potentiometric titration, providing a convenient and precise protocol for researchers in the field.

42 ENGINEERING↗

Effect of Thermodynamic and Environmental Factors on Crystallization of DNA‐Origami Superlattices

The directed self‐assembly of nanoscale materials into ordered superlattices presents a powerful strategy for creating next‐generation materials with programmable mechanical, optical, and photonic properties. Deoxyribonucleic acid (DNA) origami has emerged as a versatile scaffold for encoding nanoscale geometry and guiding the crystallization of complex 3D architectures. However, a systematic understanding of the parameters that govern the efficiency and quality of superlattice formation remains limited. In this study, we utilize octahedral DNA nanoscale frames as a model system to investigate the relative influence of key factors, including buffer composition, ionic strength, frame concentration, and thermal annealing protocols, on the size, order, and reproducibility of the resulting superlattices. Our findings provide a quantitative framework to rationally optimize DNA‐based assembly pathways. Structural characterization via small‐angle x‐ray scattering (SAXS), scanning electron microscopy (SEM), and optical microscopy validates the quality and fidelity of the assembled lattices. Moreover, by templating these DNA frameworks into inorganic replicas, we establish general design principles that extend beyond biomolecular systems, providing a foundation for the synthesis of programmable materials in broader nanofabrication contexts.

77 NANOSCIENCE AND NANOTECHNOLOGY↗

Camera settings and biome influence the accuracy of citizen science approaches to camera trap image classification

Scientists are increasingly using volunteer efforts of citizen scientists to classify images captured by motion-activated trail cameras. The rising popularity of citizen science reflects its potential to engage the public in conservation science and accelerate processing of the large volume of images generated by trail cameras. While image classification accuracy by citizen scientists can vary across species, the influence of other factors on accuracy is poorly understood. Inaccuracy diminishes the value of citizen science derived data and prompts the need for specific best-practice protocols to decrease error. We compare the accuracy between three programs that use crowdsourced citizen scientists to process images online: Snapshot Serengeti, Wildwatch Kenya, and AmazonCam Tambopata. We hypothesized that habitat type and camera settings would influence accuracy. To evaluate these factors, each photograph was circulated to multiple volunteers. All volunteer classifications were aggregated to a single best answer for each photograph using a plurality algorithm. Subsequently, a subset of these images underwent expert review and were compared to the citizen scientist results. Classification errors were categorized by the nature of the error (e.g., false species or false empty), and reason for the false classification (e.g., misidentification). Our results show that Snapshot Serengeti had the highest accuracy (97.9%), followed by AmazonCam Tambopata (93.5%), then Wildwatch Kenya (83.4%). Error type was influenced by habitat, with false empty images more prevalent in open-grassy habitat (27%) compared to woodlands (10%). For medium to large animal surveys across all habitat types, our results suggest that to significantly improve accuracy in crowdsourced projects, researchers should use a trail camera set up protocol with a burst of three consecutive photographs, a short field of view, and determine camera sensitivity settings based on in situ testing. Accuracy level comparisons such as this study can improve reliability of future citizen science projects, and subsequently encourage the increased use of such data.

54 ENVIRONMENTAL SCIENCES↗

Visibility of Hypovascularized Liver Tumors during Intra-Arterial Therapy Using Split-Bolus Single-Phase Cone Beam CT

Purpose: To validate a split-bolus contrast injection protocol for single-phase CBCT in terms of detectability of hypovascular liver tumors compared to digital subtraction angiography (DSA). Materials and Methods: In this retrospective, single-center study, 20 consecutive patients with in total 77 hypovascularized tumors referred for intra-arterial therapy received a split-bolus single-phase CBCT. Two readers rated the visibility of the target tumors scheduled for embolization in CBCT and DSA compared to the pre-interventional multiphasic CT or MRI used as reference on a 3-point scoring system (1 = optimal, 3 = not visible) and catheter-associated artifacts (1 = none, 3 = extended). SNR, CNR and contrast values were derived from 37 target tumors in CBCT and MRI. Statistical analysis included the kappa test to determine interrater reliability, the Friedman’s test for the inter-modality comparison evaluating tumor visibility in DSA and CBCT as well as for quantitative assessment. Post hoc analysis included the Wilcoxon signed-rank test. p values < 0.05 were considered significant. Results: Ninety percentage of target tumors were rated as visible in CBCT and 37.5% in DSA (p < 0.001). 70.1% of pre-interventionally detected hypovascularized tumors were depicted with CBCT and 31.2% by DSA (p < 0.001). 7.8% of known tumors were outside the FOV. Quantitative assessment showed higher image contrasts in CBCT (1.91 ± 7.01) compared to hepatobiliary-phase MRI (0.29 ± 0.14, p = 0.003) and to portal-venous (p.v.) MRI (0.31 ± 0.13, p < 0.001), but higher CNR for MRI (1.18 ± 0.80; 13.92 ± 15.82; 13.79 ± 6.65). Conclusion: In conclusion, the split-bolus single-phase CBCT detects significantly more hypovascularized liver tumors compared to DSA performed through the proper hepatic artery with high image contrasts. Level of Evidence: Level III, diagnostic study.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Pulmonary Artery Invasion, High-Dose Radiation, and Overall Survival in Patients With Non-Small Cell Lung Cancer

Purpose: To investigate whether high-dose radiation to the pulmonary artery (PA) affects overall survival (OS) in patients with non-small cell lung cancer (NSCLC). Methods and Materials: Patients with medically inoperable/unresectable NSCLC treated with definitive radiation therapy in prospective studies were eligible for this study. Pulmonary artery involvement was defined on the basis of pretreatment chest CT and positron emission tomography/CT fusion. Pulmonary artery was contoured according to the Radiation Therapy Oncology Group protocol 1106 atlas, and dose-volume histograms were generated. Results: A total of 100 patients with a minimum follow-up of 1 year for surviving patients were enrolled: 82.0% underwent concurrent chemoradiation therapy. Radiation dose ranged from 60 to 85.5 Gy in 30-37 fractions. Patients with PA invasion of grade ≤2, 3, 4, and 5 had 1-year OS and median survival of 67% and 25.4 months (95% confidence interval [CI] 15.7-35.1), 62% and 22.2 months (95% CI 5.8-38.6), 90% and 35.8 months (95% CI 28.4-43.2), and 50% and 7.0 months, respectively (P=.601). Two of the 4 patients with grade 5 PA invasion died suddenly from massive hemorrhage at 3 and 4.5 months after completion of radiation therapy. Maximum and mean doses to PA were not significantly associated with OS. The V45, V50, V55, and V60 of PA were correlated significantly with a worse OS (P<.05). Patients with V45 >70% or V60 >37% had significantly worse OS (13.3 vs 37.9 months, P<.001, and 13.8 vs 37.9 months, P=.04, respectively). Conclusions: Grade 5 PA invasion and PA volume receiving more than 45-60 Gy may be associated with inferior OS in patients with advanced NSCLC treated with concurrent chemoradiation.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Assessing the Psychological Impact of Daily Bowel Preparation on Prostate Patients Who Receive Radiation Therapy

Evidence has shown that the prostate moves depending on filling of the rectum and, to a lesser extent, the bladder; many radiation therapy departments have adopted standardized bladder filling/rectal emptying protocols for radiotherapy treatment. Daily treatments may be delayed until appropriate volumes are attained; the resultant psychological impact of these delays on patients is unknown. The purpose of this study was to determine levels of anxiety, depression, distress, and bother related to bowel preparation for prostate cancer patients undergoing radiation therapy treatment.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Perdeuteration, crystallization, data collection and comparison of five neutron diffraction data sets of complexes of human galectin-3C

Galectin-3 is an important protein in molecular signalling events involving carbohydrate recognition, and an understanding of the hydrogen-bonding patterns in the carbohydrate-binding site of its C-terminal domain (galectin-3C) is important for the development of new potent inhibitors. The authors are studying these patterns using neutron crystallography. Here, the production of perdeuterated human galectin-3C and successive improvement in crystal size by the development of a crystal-growth protocol involving feeding of the crystallization drops are described. The larger crystals resulted in improved data quality and reduced data-collection times. Furthermore, protocols for complete removal of the lactose that is necessary for the production of large crystals of apo galectin-3C suitable for neutron diffraction are described. Five data sets have been collected at three different neutron sources from galectin-3C crystals of various volumes. It was possible to merge two of these to generate an almost complete neutron data set for the galectin-3C–lactose complex. As a result, these data sets provide insights into the crystal volumes and data-collection times necessary for the same system at sources with different technologies and data-collection strategies, and these insights are applicable to other systems.

59 BASIC BIOLOGICAL SCIENCES↗

Night shift schedule causes circadian dysregulation of DNA repair genes and elevated DNA damage in humans

Circadian disruption has been identified as a risk factor for health disorders such as obesity, cardiovascular disease, and cancer. Although epidemiological studies suggest an increased risk of various cancers associated with circadian misalignment due to night shift work, the underlying mechanisms have yet to be elucidated. Here, we sought to investigate the potential mechanistic role that circadian disruption of cancer hallmark pathway genes may play in the increased cancer risk in shift workers. In a controlled laboratory study, we investigated the circadian transcriptome of cancer hallmark pathway genes and associated biological pathways in circulating leukocytes obtained from healthy young adults during a 24‐hour constant routine protocol following 3 days of simulated day shift or night shift. The simulated night shift schedule significantly altered the normal circadian rhythmicity of genes involved in cancer hallmark pathways. A DNA repair pathway showed significant enrichment of rhythmic genes following the simulated day shift schedule, but not following the simulated night shift schedule. In functional assessments, we demonstrated that there was an increased sensitivity to both endogenous and exogenous sources of DNA damage after exposure to simulated night shift. Our results suggest that circadian dysregulation of DNA repair may increase DNA damage and potentiate elevated cancer risk in night shift workers.

circadian misalignment↗

A method for normalizing pathology images to improve feature extraction for quantitative pathology

Purpose: With the advent of digital slide scanning technologies and the potential proliferation of large repositories of digital pathology images, many research studies can leverage these data for biomedical discovery and to develop clinical applications. However, quantitative analysis of digital pathology images is impeded by batch effects generated by varied staining protocols and staining conditions of pathological slides. Methods: To overcome this problem, this paper proposes a novel, fully automated stain normalization method to reduce batch effects and thus aid research in digital pathology applications. Their method, intensity centering and histogram equalization (ICHE), normalizes a diverse set of pathology images by first scaling the centroids of the intensity histograms to a common point and then applying a modified version of contrast-limited adaptive histogram equalization. Normalization was performed on two datasets of digitized hematoxylin and eosin (H&E) slides of different tissue slices from the same lung tumor, and one immunohistochemistry dataset of digitized slides created by restaining one of the H&E datasets. Results: The ICHE method was evaluated based on image intensity values, quantitative features, and the effect on downstream applications, such as a computer aided diagnosis. For comparison, three methods from the literature were reimplemented and evaluated using the same criteria. The authors found that ICHE not only improved performance compared with un-normalized images, but in most cases showed improvement compared with previous methods for correcting batch effects in the literature. Conclusions: ICHE may be a useful preprocessing step a digital pathology image processing pipeline.

61 RADIATION PROTECTION AND DOSIMETRY↗

SU-F-J-203: Retrospective Assessment of Delivered Proton Dose in Prostate Cancer Patients Based On Daily In-Room CT Imaging

Purpose: Retrospective calculation of the delivered proton dose in prostate cancer patients based on a unique dataset of daily CT images. Methods: Inter-fractional motion in prostate cancer patients treated at our proton facility is counteracted by water-filled endorectal ballon and bladder filling protocol. Typical plans (XiO, Elekta Instruments AB, Stockholm) for 74 Gy(RBE) sequential boost treatment in 37 fractions include two series of opposing lateral double-scattered proton beams covering the respective iCTV. Stability of fiducial markers and anatomy were checked in 12 patients by daily scheduled in-room control CT (cCT) after immobilization and positioning according to bony anatomy utilizing orthogonal X-ray. In RayStation 4.6 (RaySearch Laboritories AB, Stockholm), all cCTs are delineated retrospectively and the treatment plans were recalculated on the planning CT and the registered cCTs. All fraction doses were accumulated on the planning CT after deformable registration. Parameters of delivered dose to iCTV (D98%>95%, D2%<107%), bladder (V75Gy<15%, V70Gy<25%, V65Gy<30%), rectum (V70Gy<10%, V50Gy<40%) and femoral heads (V50Gy<5%) are compared to those in the treatment plan. Intra-therapy variation is represented in DVH bands. Results: No alarming differences were observed between planned and retrospectively accumulated dose: iCTV constraints were met, except for one patient (D98%=94.6% in non-boosted iCTV). Considered bladder and femoral head values were below the limits. Rectum V70Gy was slightly exceeded (<11.3%) in two patients. First intra-therapy variability analysis in 4 patients showed no timedependent parameter drift, revealed strongest variability for bladder dose. In some fractions, iCTV coverage (D98%) and rectum V70Gy was missed. Conclusion: Double scattered proton plans are accurately delivered to prostate cancer patients due to fractionation effects and the applied precise positioning and immobilization protocols. As a result of rare interventions after daily 3D imaging of the first 12 patients, in-room CT frequency for prostate cancer patients was reduced. The presented study supports this decision. The authors acknowledge the German Federal Ministry for Education and Research for funding the High Precision Radiotherapy Group at the OncoRay - National Center for Radiation Research in Oncology (BMBF- 03Z1N51).

60 APPLIED LIFE SCIENCES↗

Species-specific ribosomal RNA-FISH identifies interspecies cellular-material exchange, active-cell population dynamics and cellular localization of translation machinery in clostridial cultures and co-cultures

ABSTRACT The development of synthetic microbial consortia in recent years has revealed that complex interspecies interactions, notably the exchange of cytoplasmic material, exist even among organisms that originate from different ecological niches. Although morphogenetic characteristics, viable RNA and protein dyes, and fluorescent reporter proteins have played an essential role in exploring such interactions, we hypothesized that ribosomal RNA-fluorescence in situ hybridization (rRNA-FISH) could be adapted and applied to further investigate interactions in synthetic or semisynthetic consortia. Despite its maturity, several challenges exist in using rRNA-FISH as a tool to quantify individual species population dynamics and interspecies interactions using high-throughput instrumentation such as flow cytometry. In this work, we resolve such challenges and apply rRNA-FISH to double and triple co-cultures of Clostridium acetobutylicum, Clostridium ljungdahlii, and Clostridium kluyveri . In pursuing our goal to capture each organism’s population dynamics, we demonstrate dynamic rRNA, and thus ribosome, exchange between the three species leading to the formation of hybrid cells. We also characterize the localization patterns of the translation machinery in the three species, identifying distinct, dynamic localization patterns among them. Our data also support the use of rRNA-FISH to assess the culture’s health and expansion potential, and, here again, our data find surprising differences among the three species examined. Taken together, our study argues for rRNA-FISH as a valuable and accessible tool for quantitative exploration of interspecies interactions, especially in organisms which cannot be genetically engineered or in consortia where selective pressures to maintain recombinant species cannot be used. IMPORTANCE Though dyes and fluorescent reporter proteins have played an essential role in identifying microbial species in co-cultures, we hypothesized that ribosomal RNA-fluorescence in situ hybridization (rRNA-FISH) could be adapted and applied to quantitatively probe complex interactions between organisms in synthetic consortia. Despite its maturity, several challenges existed before rRNA-FISH could be used to study Clostridium co-cultures of interest. First, species-specific probes for Clostridium acetobutylicum and Clostridium ljungdahlii had not been developed. Second, “state-of-the-art” labeling protocols were tedious and often resulted in sample loss. Third, it was unclear if FISH was compatible with existing fluorescent reporter proteins. We resolved these key challenges and applied the technique to co-cultures of C. acetobutylicum , C. ljungdahlii , and Clostridium kluyveri . We demonstrate that rRNA-FISH is capable of identifying rRNA/ribosome exchange between the three organisms and characterized rRNA localization patterns in each. In combination with flow cytometry, rRNA-FISH can capture sub-population dynamics in co-cultures.

Hill, John D.↗

PV Cyber Security Research (Final Report)

Extensive deployment of interoperable distributed energy resources (DER) on power systems is increasing the power system cyber security attack surface. National and jurisdictional interconnection standards require DER to include a range of autonomous and commanded grid support functions which can drastically influence power quality, voltage, and bulk system frequency. This project was split into two phases. The first provided a survey and roadmap of the cybersecurity for the solar industry. The second investigated multiple PV cybersecurity research and development (R&D) concepts identified in the first phase. In the first year, the team created a roadmap for improving cybersecurity for distributed solar energy resources. This roadmap was intended to provide direction for the nation over the next five years and focused on the intersection of industry and government and recommends activities in four related areas: stakeholder engagement, cyber security research and development, standards development, and industry best practices. At the same time, the team produced a primer for DER vendors, aggregators, and grid operators to establish a common taxonomy and describe basic principles of cyber security, encryption, communication protocols, DER cyber security recommendations and requirements, and device-, aggregator-, and utility-level security best practices to ensure data confidentiality, integrity, and availability. This material was motivated by the need to assist the broader PV industry with cybersecurity resilience and describe the state-of-the-art for securing DER communications. Lastly, an adversary-based assessment of multiple PV devices was completed at the Distributed Energy Technologies Laboratory at Sandia National Laboratories to determine the status of industry cybersecurity practices. The team found multiple deficiencies in the security features of the assessed devices. In the second year, a set of recommendations was created for DER communication protocols— especially with respect to the state-of-the-art requirements in IEEE 2030.5. Additionally, several cybersecurity R&D technologies related to communications-enabled photovoltaic systems were studied to harden DER communication networks. Specifically, the team investigated (a) using software defined networking to create a moving target defense system for DER communications, and (b) engineering controls that prevent misprogramming or adversary action on DER devices/networks by disallowing setpoints that will generate unstable power system operations.

14 SOLAR ENERGY↗

Geochemistry and metagenomics analyses of bacterial community structure in selected waste dumpsites in Lagos Metropolis, Nigeria

Dumpsites are reservoirs of persistent organic pollutants (POPs) and heavy metals (HMs), constituting environmental hazards to humanity. Autochthonous microorganisms in dumpsites exhibit various degrees of responses to contaminants. Unfortunately, there is a dearth of information on the types and concentration of pollutants and the array of microorganisms in these dumpsites which may play important roles in the metabolism of such pollutants or other community processes. Therefore, determining the microbial community structure in such contaminated sites across a municipality is essential for profiling the taxa that would serve as consensus degraders of the pollutants. In this study, soil samples from three dumpsites (Cele, CS; Solous, SS; and Computer Village, CVS) were characterized for geochemical properties using GC-MS, MP-AES, and other analytical protocols, while the dynamics of bacterial communities were evaluated based on their 16S rRNA gene barcodes. A significant difference in the bacterial communities was observed among the dumpsites in relation to the extent of pollution caused by POPs and HMs. CVS, with the highest HM contamination, was rich in Actinobacteria (41.7%) and Acidobacteria (10.2%), in contrast to CS and SS. Proteobacteria (34.1%) and Firmicutes (20%) were the dominant phyla in CS (highest POP contamination), while Bacteroidetes (45.5%) and Proteobacteria (39.9%) were dominant in SS soil.Bacilluswas the dominant genus in the most polluted dumpsite. Canonical correspondence analysis revealed that polycyclic aromatic hydrocarbons (PAHs) and HMs shaped the structure of the bacterial operational taxonomic units (OTUs) in the most polluted dumpsite. Out of a total of 706 OTUs, 628 OTUs exhibited a significant correlation (>50%) with benzo(b)fluoranthene, azobenzene, dibenzofurans, pyrene, dibenzo(a,l)pyrene, Cu, and Zn. In particular, Proteobacteria (Achromobactersp. andSerratiasp.), Bacteroidetes (Zhouiasp.), and Firmicutes (Bacillussp.) were suggested to be pivotal to the ecophysiology of dumpsite soils contaminated with POPs and HMs. The results generally underscored the importance of metagenomic and physicochemical analyses of polluted systems in enabling correlations for useful prediction of drivers of such ecosystems. This will further improve our understanding of the metabolic potential and adaptation of organisms in such systems.

Environmental Sciences & Ecology↗

Chemoradiation With Paclitaxel and Carboplatin in High-Risk Cervical Cancer Patients After Radical Hysterectomy: A Korean Gynecologic Oncology Group Study

Purpose: To evaluate the efficacy and toxicity of concurrent chemoradiation with paclitaxel and carboplatin in patients with high-risk cervical cancer. Methods and Materials: Patients after radical hysterectomy for cervical cancer, with at least 1 high-risk characteristic, were administered paclitaxel 135 mg/m{sup 2}, carboplatin area under the curve = 5 every 3 weeks for 3 cycles concomitant with radiation therapy as adjuvant treatment. Results: This prospective study enrolled 71 consecutive patients. Sixty-six patients (93%) completed the planned treatment. The majority of grade 3/4 neutropenia or nonhematologic toxicities were usually self-limited. Diarrhea grades 3/4 were observed in 4 patients (5.6%). One patient developed anaphylactic shock after infusion of paclitaxel. With a median follow-up of 57 months, recurrences occurred in 16 patients. Multivariable analysis indicated that common iliac lymph node involvement is an independent risk factor for disease recurrence (odds ratio 13.48; 95% confidence interval 2.93-62.03). In the intent-to-treat population (n=71), the estimated 5-year disease-free survival and overall survival rates were 77.3% and 80.3% respectively. In the per-protocol population (n=62), disease-free survival was 78.9% and overall survival was 83.9%. Conclusions: Concurrent chemoradiation with paclitaxel/carboplatin is well tolerated and seems to be effective for patients who undergo radical hysterectomy. Therefore, a prospective, randomized controlled study should be designed to evaluate efficacy of this approach for patients with high-risk cervical cancer.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Clinical Experience and Evaluation of Patient Treatment Verification With a Transit Dosimeter

Purpose: To prospectively evaluate a protocol for transit dosimetry on a patient population undergoing intensity modulated radiation therapy (IMRT) and to assess the issues in clinical implementation of electronic portal imaging devices (EPIDs) for treatment verification. Methods and Materials: Fifty-eight patients were enrolled in the study. Amorphous silicon EPIDs were calibrated for dose and used to acquire images of delivered fields. Measured EPID dose maps were back-projected using the planning computed tomographic (CT) images to calculate dose at prespecified points within the patient and compared with treatment planning system dose offline using point dose difference and point γ analysis. The deviation of the results was used to inform future action levels. Results: Two hundred twenty-five transit images were analyzed, composed of breast, prostate, and head and neck IMRT fields. Patient measurements demonstrated the potential of the dose verification protocol to model dose well under complex conditions: 83.8% of all delivered beams achieved the initial set tolerance level of Δ{sub D} of 0 ± 5 cGy or %Δ{sub D} of 0% ± 5%. Importantly, the protocol was also sensitive to anatomic changes and spotted that 3 patients from 20 measured prostate patients had undergone anatomic change in comparison with the planning CT. Patient data suggested an EPID-reconstructed versus treatment planning system dose difference action level of 0% ± 7% for breast fields. Asymmetric action levels were more appropriate for inversed IMRT fields, using absolute dose difference (−2 ± 5 cGy) or summed field percentage dose difference (−6% ± 7%). Conclusions: The in vivo dose verification method was easy to use and simple to implement, and it could detect patient anatomic changes that impacted dose delivery. The system required no extra dose to the patient or treatment time delay and so could be used throughout the course of treatment to identify and limit systematic and random errors in dose delivery for patient groups.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Complications of Microwave Ablation for Liver Tumors: Results of a Multicenter Study

Purpose: New technologies for microwave ablation (MWA) have been conceived, designed to achieve larger areas of necrosis compared with radiofrequency ablation (RFA). The purpose of this study was to report complications by using this technique in patients with focal liver cancer. Methods: Members of 14 Italian centers used a 2.45-GMHz generator delivering energy through a cooled miniature-choke MW antenna and a standardized protocol for follow-up. They completed a questionnaire regarding number and type of deaths, major and minor complications and side effects, and likelihood of their relationship to the procedure. Enrollment included 736 patients with 1.037 lesions: 522 had hepatocellular carcinoma with cirrhosis, 187 had metastases predominantly from colorectal cancer, and 27 had cholangiocellular carcinoma. Tumor size ranged from 0.5 to 10 cm. In 13 centers, the approach used was percutaneous, in 4 videolaparoscopic, and in 3 laparotomic. Results: No deaths were reported. Major complications occurred in 22 cases (2.9%), and minor complications in 54 patients (7.3%). Complications of MWA do not differ from those RFA, both being based on the heat damage. Conclusion: Results of this multicenter study confirmed those of single-center experiences, indicating that MWA is a safe procedure, with no mortality and a low rate of major complications. The low rate of complications was probably due to precautions adopted, knowing in advance possible risk conditions, on the basis of prior RFA experience.

62 RADIOLOGY AND NUCLEAR MEDICINE↗