Internal Margin Research Articles

Uncleared margin rules — initial margin: It’s time to commence the journey

This paper aims to provide significant evidence that suggests many of the impacted entities in Phases 4 and 5 are still going through the stages of discovery on the complexity of the uncleared margin rules (UMR) initial margin requirements. To educate themselves they must cultivate knowledge through those that have already gone through the process and the industry vendors that would have experienced the different issues that had arisen through the previous three phases of UMR. Cementing that understanding is going to be critical for institutions. They need to be able to mitigate the risks, problems and issues that present themselves as they build, develop and execute on an implementation plan. They also need to utilise the external levers that are available to them and give themselves the best opportunity to end up with an efficient, robust and integrated operating model that transforms their internal collateral and margin capabilities. The reader can expect to take away a number of facts, considerations and solutions that will impact security, custody and Phases 4 and will be of especial interest to 5 firms preparing for UMR in 2019 through to 2020.

Noninvasive cardiac arrhythmia ablation with particle beams.

Cardiac arrhythmias are a major health burden, associated with reduced quality of life and substantial morbidity and mortality. Current therapy includes moderately effective medication and catheter-based ablation of arrhythmogenic substrates in the heart. Catheter interventions frequently have to be repeated due to recurrent arrhythmia, can have rare but severe side-effects and are less suited especially for potentially lethal left ventricular tachycardia. Noninvasive alternatives are therefore warranted. Photon and ion beam radiotherapy has been studied in animal models and first patient cases have been reported using photons. Ion beams might offer the possibility to greatly reduce dose to surrounding healthy tissue, including critical cardiac substructures. Based on a recently conducted animal study, we report advantages and disadvantages of 4D-ion beam therapy, and strategies necessary for a clinical transition. Motion management of both respiration and heartbeat are discussed, as well as range uncertainty resulting from both regular motion and interfractional anatomic changes. Image guidance both in 3D and 4D has to be employed for a safe irradiation, but also population-based data on motion variability and time behavior of interfractional changes are necessary. Range verification could play a crucial role at least during development of clinical protocols. For clinical realization, it appears necessary to suppress or conformally mitigate the large respiratory motion to avoid normal tissue complications. Cardiac motion has to be incorporated into treatment planning, either through adequate range-considering internal margins or through more conformal strategies such as ECG-based gating or even 4D-optimization. The latter strategies would necessitate online 4D image guidance.

Intrafraction Motion Management of Renal Cell Carcinoma With Magnetic Resonance Imaging-Guided Stereotactic Body Radiation Therapy

PurposeOne of the major challenges in stereotactic body radiation therapy (SBRT) of renal cell carcinoma is internal motion during treatment. Previous literature has aimed to mitigate the effects of motion by expanding the treatment margins or respiratory tracking. Online magnetic resonance imaging (MRI)-guided radiation therapy has the potential to further improve the treatment of renal cell carcinoma by direct visualization of the tumor during treatment. The efficacy of 2 motion management techniques were assessed: tumor trailing and respiratory tracking. The simulation of a single-fraction, MRI-based SBRT was performed to quantify intrafraction motion and assess the efficacy of the different motion management strategies. Methods and materialsFifteen patients were included in the study. At the beginning and end of the scanning protocol, 2 cine-MRI scans were acquired to assess cyclic respiratory motion. In addition, 3-dimensional spoiled gradient echo scans were acquired at 4 different time points to assess the slow drifts over 25 minutes. The systematic and random errors owing to intrafraction drift were calculated, as well as the random error induced by respiratory motion. The motion margins were calculated for tumor trailing and respiratory tracking and compared with the margin when no motion compensation would be performed to assess the relative efficacy of each technique. ResultsThe largest respiratory tumor motion was observed along the caudo-cranial direction with a median 95% maximum amplitude of approximately 12 mm. ΣDRIFT, σDRIFT, and σRESP were determined to be 1.0 mm 1.8 mm, and 3.8 mm, respectively. Without mechanical immobilization, intrafraction drift accounted for 75% of the total intrafraction motion margin for online midposition-based SBRT treatments. ConclusionsThe contribution of intrafraction drift to the total internal motion margin is much larger than periodic respiratory motion. This makes tumor trailing a viable option to consider on the MRI linac because it allows for 3-dimensional MRI acquisitions during beam delivery, which simplifies the introduction of new techniques, such as dose accumulation and online intrafraction replanning.

Metodologia alternativa na construção de indicadores de eficiência para a avaliação de escolas

Resumo Este estudo teve como objetivo apresentar a construção de um indicador educacional que derivou das variáveis que compõem o fluxo do alunado na escola, utilizando a Análise Envoltória de Dados (DEA). O tratamento dos dados pela DEA possibilitou apurar as medidas de eficiência de cada unidade escolar e criar uma fronteira de referência interna para a rede municipal de ensino de Campinas. O princípio básico foi de obter pesos ideais para a contribuição de cada uma dessas variáveis na elaboração do indicador.

Equivalence analyses of dissolution profiles with the Mahalanobis distance.

For some postapproval changes, the manufacturer has to demonstrate that the dissolution profile of the drug product before the change is statistically equivalent to the dissolution profile after the change. Guidelines suggest the so-called similarity factor f2 as standard approach for the equivalence analysis. f2 is a statistically questionable transformation of the Euclidean distance between both profile means and does not allow a control of the type I error rate. An alternative multivariate distance measure for quantifying the dissimilarity between both profile groups is the Mahalanobis distance. Current equivalence procedures based on the Mahalanobis distance implicate some practical problems in the dissolution context: either one chooses an exact method but the determination of a product independent equivalence margin will not be practically feasible or one chooses an approximate alternative that suffers from the bias of the Mahalanobis distance point estimate. This paper suggests the T2EQ approach for dissolution profile comparisons. T2EQ is a practically feasible equivalence procedure based on the Mahalanobis distance with an internal equivalence margin for comparing dissolution profiles. The equivalence margin is compliant with current dissolution guidelines. The operating characteristics (size, robustness, and power) are investigated via simulation: T2EQ meets the needs of both authorities and industry: not affected by the bias of the point estimate the type I error rate can be reliably controlled for various distribution assumptions and the power of T2EQ exceeds the power of methods recently discussed in the literature. These results were presented for the first time at CEN-ISBS 2017.

Apport de la radiothérapie guidée par l’image et repositionnement du patient dans le cancer anorectal

Intensity-modulated radiation therapy is recommended in anal squamous cell carcinoma treatment and is increasingly used in rectal cancer. It adapts the dose to target volumes, with a high doses gradient. Intensity-modulated radiation therapy allows to reduce toxicity to critical normal structures and to consider dose-escalation studies or systemic treatment intensification. Image-guided radiation therapy is a warrant of quality for intensity-modulated radiation therapy, especially for successful delivery of the dose as planned. There is no recommended international or national anorectal cancer image-guided radiation therapy protocol currently available. Dose-escalation trials or expert opinions about intensity-modulated/image-guided radiation therapy good practice guidelines recommend daily volumetric imaging throughout the treatment or during the five first fractions and weekly thereafter as a minimum. Image-guided radiation therapy allows to reduce margins related to patient setup errors. Internal margin, related to the internal organ motion, needs to be adapted according to short- or long-course radiotherapy, gender, rectal location; it can be higher than current recommended planning target volume margins, particularly in the upper and anterior part of mesorectum, which has the most significant movement. Image-guided radiation therapy based on volumetric imaging allows to take target volume shrinkage into account and to develop adaptive strategies, in particular for mesorectum shrinkage during rectal cancer treatment. Lastly, the emergence of new image-guided radiation therapy technologies including MRI (which plays a major role in pelvic tumours assessment and diagnosis) opens up interesting perspectives for adaptive radiotherapy, taking into account both organs’ movements and tumour shrinkage.

Intrafraction esophageal motion in patients with clinical T1N0 esophageal cancer.

To investigate the intrafraction movement of the esophagus using fiducial markers. Studies on intrafraction esophageal motion using the fiducial markers are scarce. We retrospectively analyzed patients with clinical T1N0 esophageal cancer who had received fiducial markers at our hospital between July 2007 and December 2013. Real-Time Position Management System to track the patient's respiration was used, and each patient underwent three-dimensional computed tomography of the resting expiratory and inspiratory level. We used the center of the marker to calculate the distance between the expiratory and inspiratory breath-holds, which were measured with the radiotherapy treatment planning system in three directions: left-right (LR), superior-inferior (SI), and anterior-posterior (AP). The movements at each site were compared with the Kruskal-Wallis analysis and Wilcoxon rank sum test with a Bonferroni correction. A total of 101 patients with 201 fiducial markers were included. The upper, middle and lower thoracic positions had 40, 77, and 84 markers, respectively. The mean absolute magnitudes of the shifts (standard deviation) were 0.18 (0.19) cm, 0.68 (0.46) cm, and 0.24 (0.24) cm in the LR, SI, and AP directions, respectively. From the cumulative frequency distribution, we assumed that 0.35 cm LR, 0.8 cm SI, and 0.3 cm AP in the upper; 0.5 cm LR, 1.55 cm SI, and 0.55 cm AP in the middle; and 0.75 cm LR, 1.9 cm SI, and 0.95 cm AP in the lower thoracic esophagus covered 95% of the cases. The internal margin based on the site of esophagus was estimated.

Abstract 579: Magnetic resonance imaging of the breast and radiomics analysis for an improved early prediction of the response to neoadjuvant chemotherapy in breast cancer patients

Abstract Background and Aim In patients undergoing neoadjuvant chemotherapy for breast cancer the achievement of a pathological complete response (pCR) is associated with a significantly improved disease-free and overall survival. Therefore, accurate means to predict treatment response as early as possible are desirable to identify women who don't benefit from this cytotoxic therapy. Several studies have demonstrated that dynamic contrast-enhanced MRI is the most sensitive method for the assessment and prediction of treatment response. In the past decade, the field of medical image analysis has grown exponentially, with an increased number of pattern recognition tools and an increase in data set sizes. These advances have facilitated the development of processes for high-throughput extraction of quantitative features that result in the conversion of images into mineable data and the subsequent analysis of these data for decision support. This emerging field in medical research is termed radiomics. The aim of this study was to assess radiomics with dynamic contrast-enhanced (DCE) MRI for the early prediction of pathological complete response (pCR) in breast cancer patients undergoing neoadjuvant chemotherapy. Methods and materials In this IRB approved prospective study 41 women with breast cancer scheduled for NAC were included and underwent MRI of the breast at 3T with DCE and T2-weighted imaging prior to and after two cycles of NAC. For each lesion a total of 14 features were extracted ranging from morphological and kinetic MRI ADC parameters. A recursive feature elimination method along with five different classifiers was performed including: linear support vector machine (SVM), linear discriminant analysis (LDA), logistic regression (LR), random forest (RF), and stochastic gradient descent (SGD) was employed to rank the features. Histopathology using the Residual Cancer Burden (RCB) score and class calculated from post-treatment surgical specimen and patient outcomes were used as the standard of reference. Results Classification accuracy was assessed for pCR as defined by the RCB score, metastases and disease specific death. Radiomics analysis of MRI data achieved AUCs for RCB score (AUC 0.85), metastases (AUC 0.87) based on RF and death (AUC 0.92) based on SVM. The most relevant parameters for prediction of RCB score were mass internal enhancement characteristics, shape and margins with DCE, for metastasis peri-tumoral edema on T2-weighted imaging, mass margins and internal enhancement characteristics, and for death high signal intensity on T2-weighted imaging, mass margins, and internal enhancement characteristics. Conclusion Radiomics with MRI of the breast using DCE and T2-weighted imaging enables prediction of response to NAC with high accuracy and thus can provide predictive information to guide treatment decisions. Citation Format: Katja Pinker-Domenig, Amirhessam Tahmassebi, Georg Wengert, Thomas H. Helbich, Zsuzsanna Bago-Horvath, Elizabeth A. Morris, Anke Meyer-Baese. Magnetic resonance imaging of the breast and radiomics analysis for an improved early prediction of the response to neoadjuvant chemotherapy in breast cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 579.

Segmental analysis of respiratory liver motion in patients with and without a history of abdominal surgery.

The purpose of this study was to analyze the respiratory motion of each segment of the liver in patients with or without a history of abdominal surgery using four-dimensional computed tomography. In total, 57 patients treated for abdominal tumors using proton beam therapy were enrolled. Eighteen patients had a history of abdominal surgery and 39 did not. The positions of clearly demarcated, high-density regions in the liver were measured as evaluation points with which to quantify the motion of each liver segment according to the Couinaud classification. In total, 218 evaluation points were analyzed. Comparison of differences in the motion of individual liver segments showed that among patients without a history of surgery, the maximum was 29.0 (7.2-42.1)mm in S6 and the minimum was 15.1 (10.6-19.3)mm in S4. Among patients with a history of surgery, the maximum was 28.0 (9.0-37.4)mm in S7 and the minimum was 6.3 (4.1-9.3)mm in S3. The distances and directions of respiratory motion differed for each liver segment, and a history of abdominal surgery reduced the respiratory motion of the liver. It is necessary to selectively use the internal margin setting.

Quantifying esophageal motion during free-breathing and breath-hold using fiducial markers in patients with early-stage esophageal cancer

IntroductionCardiac toxicity after definitive chemoradiotherapy for esophageal cancer is a critical issue. To reduce irradiation doses to organs at risk, individual internal margins need to be identified and minimized. The purpose of this study was to quantify esophageal motion using fiducial makers based on four-dimensional computed tomography, and to evaluate the inter-CBCT session marker displacement using breath-hold.Materials and methodsSixteen patients with early stage esophageal cancer, who received endoscopy-guided metallic marker placement for treatment planning, were included; there were 35 markers in total, with 9, 15, and 11 markers in the upper thoracic, middle thoracic, and lower thoracic/esophagogastric junction regions, respectively. We defined fiducial marker motion as motion of the centroidal point of the markers. Respiratory esophageal motion during free-breathing was defined as the amplitude of individual marker motion between the consecutive breathing and end-expiration phases, derived from four-dimensional computed tomography. The inter-CBCT session marker displacement using breath-hold was defined as the amplitudes of marker motion between the first and each cone beam computed tomography image. Marker motion was analyzed in the three regions (upper thoracic, middle thoracic, and lower thoracic/esophagogastric junction) and in three orthogonal directions (right-left; anterior-posterior; and superior-inferior).ResultsRespiratory esophageal motion during free-breathing resulted in median absolute maximum amplitudes (interquartile range), in right-left, anterior-posterior, and superior-inferior directions, of 1.7 (1.4) mm, 2.0 (1.5) mm, and 3.6 (4.1) mm, respectively, in the upper thoracic region, 0.8 (1.1) mm, 1.4 (1.2) mm, and 4.8 (3.6) mm, respectively, in the middle thoracic region, and 1.8 (0.8) mm, 1.9 (2.0) mm, and 8.0 (4.5) mm, respectively, in the lower thoracic/esophagogastric region. The inter-CBCT session marker displacement using breath-hold resulted in median absolute maximum amplitudes (interquartile range), in right-left, anterior–posterior, and superior-inferior directions, of 1.3 (1.0) mm, 1.1 (0.7) mm, and 3.3 (1.8) mm, respectively, in the upper thoracic region, 0.7 (0.7) mm, 1.1 (0.4) mm, and 3.4 (1.4) mm, respectively, in the middle thoracic region, and 2.0 (0.8) mm, 2.6 (2.2) mm, and 3.5 (1.8) mm, respectively, in the lower thoracic/esophagogastric region.ConclusionsDuring free-breathing, esophageal motion in the superior-inferior direction in all sites was large, compared to the other directions, and amplitudes showed substantial inter-individual variability. The breath-hold technique is feasible for minimizing esophageal displacement during radiotherapy in patients with esophageal cancer.

EP-2058: Which internal margin to compensate uterus motion?

EP-2058: Which internal margin to compensate uterus motion?

Przypisy jako wyzwanie redakcyjne

The article presents two interesting cases from the editorial point of view, concerning the footnotes edition. These cases concern two publications: Poland of poets and painters , by prof. Franciszek Ziejka and Be as good as bread. Houses of the Congregatio Sororum Albertinorum Pauperibus Inservientium from 1891 to 2009 , prepared by Sr. Krzysztofa Maria Babraj. The projects of these publications have been characterized and the conditions determining the distribution of footnotes and their redaction and modification have been discused. In the first case, the album like book form and the requirement to preserve the design concept influenced on the utilization of the internal margin and placement the footnotes there, while the specific nature of the other publication, largely based on archive sources and intended for the diverse audience, required far-reaching editorial changes and the application of non-standard solutions. The summary highlights the importance of co-operation between the author, the editor, the designer and the persons responsible for the DTP in such cases.

Does long-term care subsidization reduce hospital admissions and utilization?

We use quasi-experimental evidence on the expansion of the public subsidization of long-term care to examine the causal effect of a change in caregiving affordability on the delivery of hospital care. More specifically, we examine a reform that both introduced a new caregiving allowance and expanded the availability of publicly funded home care services, on both hospital admissions (both on the internal and external margin) and length of stay. We find robust evidence of a reduction in both hospital admissions and utilization among both those receiving a caregiving allowance and, albeit less intensely, among beneficiaries of publicly funded home care, which amounts to 11% of total healthcare costs. These effects were stronger when regions had an operative regional health and social care coordination plan in place. Consistently, a subsequent reduction in the subsidy, five years after its implementation, is found to significantly attenuate such effects. We investigate a number of potential mechanisms, and show a number of falsification and robustness checks.

Reconceiving the grain heap

This article returns to what was once an ethnographic staple in the sociology of India: the post-harvest grain heap. Having long occupied centre stage in analyses of a moneyless, redistributive transactional order widely known as the jajmani system, it has also been the subject of influential critique, where it has been argued that the misconceived heap sustained a powerful anthropological fiction. Moving beyond these positions, which seem to have left the heap grounded in the past, the grain heap in this work is reconceptualised as a critical entry point and analytic for the study of contemporary commodity markets. Based on long-term ethnographic fieldwork in an agricultural market (mandi) in Madhya Pradesh, it finds that it is along the seams or internal margins of the market, at routine sites of physical transfer and exchange, assembly and dispersal, integration and disruption, that heaps of agricultural produce materialise. An analysis of critical aspects of the heap—its position, composition, measurement and distribution—provides sharp insights into the changing dynamics of the market and its complex relationships. In the process, it also reveals important yet often unnoticed shifts in the sources and distribution of economic and social margins, and their diverse and differentiated effects on market life and livelihoods.

Observation of different tumor motion magnitude within liver and estimate of internal motion margins in postoperative patients with hepatocellular carcinoma.

AimsTo assess motion magnitude in different parts of the liver through surgical clips in postoperative patients with hepatocellular carcinoma and to examine the correlation between the clip and diaphragm motion.MethodsFour-dimensional computed tomography images from 30 liver cancer patients under thermoplastic mask immobilization were selected for this study. Three to seven surgical clips were placed in the resection cavity of each patient. The liver volume on computed tomography image was divided into the right upper (RU), right middle (RM), right lower (RL), hilar, and left lobes. Agreement between the clip and diaphragm motion was assessed by calculating intraclass correlation coefficient, and Bland–Altman analysis (Diff). Furthermore, population-based and patient-specific margins for internal motion were evaluated.ResultsThe clips located in the RU lobe showed the largest motion, (7.5±1.6) mm, which was significantly more than in the RM lobe (5.7±2.8 mm, p=0.019), RL lobe (4.8±3.3 mm, p=0.017), and hilar lobe (4.7±2.7 mm, p<0.001) in the cranial–caudal direction. The mean intraclass correlation coefficient values between the clip and diaphragm motion were 0.915, 0.735, 0.678, 0.670, and the mean Diff values between them were 0.1±0.8 mm, 2.3±1.4 mm, 3.1±2.0 mm, 2.4±1.5 mm, when clips were located in the RU lobe, RM lobe, RL lobe, and hilar lobe, respectively. The clip and diaphragm motions had high concordance when clips were located in the RU lobe. Internal margin can be reduced from 5 mm in the cranial–caudal direction based on patient population average and to 3 mm based on patient-specific margins.ConclusionsThe motion magnitude of clips varied significantly depending on their location within the liver. The diaphragm was a more appropriate surrogate for tumor located in the RU lobe than for other lobes.

5. Working group of SFPM: To implement motion management technologies for RT in clinical routine

Geometrical accuracy of radiotherapy (RT) of intra-thoracic organs (lung, liver, pancreas and breast) is limited by patient breathing. Indeed, breathing amplitude can vary from 1 to 2 cm (sometimes more) and should be taken in account for each step of the treatment process. For example, for Non-Small Cell Lung Cancer (NSCLC), this uncertainty tends to use large internal margins that can compromise tumor dose escalation, and thus satisfying local control, because of lung DVH limitation. This problem is especially critical for stereotactic treatment delivering up to 20 Gy per fraction to the target. This French working group proposes to update and complete the TG76 report (ref 2006) using the following outline for its report. First, the nature of the breathing motion and its consequences for RT is fully described. A detailed lexicon is also proposed. Indeed, several technical terms are used in the literature and sometimes the same word is used for very different techniques. Then the different treatment modalities dealing with the motion management are reported: simple safety margins around the target, motion limitation techniques (breath-hold, abdominal compression, high frequency ventilation), breathing synchronization of the beam (gating) and target tracking. An overview of the main commercial and technical/methodological tools and their clinical advantages should help users or future users to set up the treatment modality in clinical routine. This report also describes the associated imaging techniques for planning these treatments (principle, how to use them). In particular a section is dedicated to 4DCT. In addition the in-room imaging techniques is presented and criticized. At last, consequences of interplay effect that occurs when a modulated plan is delivered to a moving target, is discussed. The group is composed of French clinical medical physicists who have a concrete/practical experience in this domain. This group also brings knowledge and tips to implement these technologies in a clinical context.

Large (≥3cm) thyroid nodules with benign cytology: Can Thyroid Imaging Reporting and Data System (TIRADS) help predict false-negative cytology?

BackgroundThere is controversy about the accuracy of the fine-needle aspiration (FNA) cytology results in large sized thyroid nodules. Our aim was to evaluate the false-negative rate of FNA for large thyroid nodules and the usefulness of the Thyroid Imaging Reporting and Data System (TIRADS) in predicting false-negative cytology for large thyroid nodules with benign cytology.Methods632 thyroid nodules larger than or equal to 3cm in size with subsequent benign cytology on US-guided FNA were included. US features of internal composition, echogenicity, margin, calcifications, and shape were evaluated, and nodules were classified according to TIRADS. TIRADS category 3 included nodules without any of the following suspicious features:solidity, hypoechogenicity or marked hypoechogenicity, microlobulated or irregular margins, microcalcifications, and taller-than-wide shape. Category 4a, 4b, 4c, and 5 were assigned to nodules showing one, two, three or four, or five suspicious US features, respectively. US features associated with malignancy for these lesions were analyzed and malignancy risk according to TIRADS was calculated.ResultsOf the 632 lesions, 23 lesions(3.6%) were malignant and 609(96.4%) were benign, suggesting a 3.6% false-negative rate for FNA cytology. Of the 23 malignant lesions, final pathology was mainly follicular carcinoma minimally invasive(65.2%, 15/23) and the follicular variant of papillary carcinoma(26.1%, 6/23). The malignancy risks of categories 3, 4a, 4b, and 4c nodules were 0.9%, 4.6%, 10.0%, and 11.8%, respectively.ConclusionLarge thyroid nodules with benign cytology had a relatively high false-negative risk of 3.6% and TIRADS was helpful in predicting false-negative cytology for these lesions.

Monolithic zirconia dental crowns. Internal fit, margin quality, fracture mode and load at fracture

ObjectiveDental all-ceramic restorations of zirconia, with and without an aesthetic veneering layer, have become a viable alternative to conventional metal-ceramic restorations. The aim of this study was to evaluate whether factors of the production methods or the material compositions affect load at fracture, fracture modes, internal fit or crown margins of monolithic zirconia crowns. MethodsSixty crowns made from six different commercially available dental zirconias were produced to a model tooth with a shallow circumferential chamfer preparation. Internal fit was assessed by the replica method. The crown margin quality was assessed by light microscopy on an ordinal scale. The cemented crowns were loaded centrally in the occlusal fossa with a horizontal steel cylinder with a diameter of 13mm at 0.5mm/min until fracture. Fractographic analysis was performed on the fractured crowns. ResultsThere were statistically significant differences among the groups regarding crown margins, internal fit and load at fracture (p<0.05, Kruskall Wallis). Fracture analyses revealed that all fractures started cervically and propagated to the occlusal surface similar to clinically observed fractures. There was statistically significant correlation between margin quality and load at fracture (Spearman’s rank correlation, p<0,05). SignificanceProduction method and material composition of monolithic zirconia crowns affect internal fit, crown margin quality and the load at fracture. The hard-machined Y-TZP zirconia crowns had the best margin quality and the highest load at fracture. Reduction of margin flaws will improve fracture strength of monolithic zirconia crowns and thereby increase clinical success.

The application of ultrasound in detecting lymph nodal recurrence in the treated neck of head and neck cancer patients

Early detection of neck lymph node (LN) recurrence is paramount in improving the prognosis of treated head and neck cancer patients. Ultrasound (US) with US-guided fine needle aspiration (FNA) and core needle biopsy (CNB) have been shown to have great accuracy for LN diagnoses in the untreated neck. However, in the treated neck with fibrosis, their roles are not clarified. Here, we retrospectively review 153 treated head and neck cancer patients who had received US and US-guided FNA/CNB. In multivariate logistic regression analyses, size (short-axis diameter >0.8 cm) (odds ratio (OR) 4.19, P = 0.007), round shape (short/long axis ratio >0.5) (OR 3.44, P = 0.03), heterogeneous internal echo (OR 3.92, P = 0.009) and irregular margin (OR 7.32, P < 0.001) are effective US features in predicting recurrent LNs in the treated neck. However, hypoechogenicity (OR 2.38, P = 0.289) and chaotic/absent vascular pattern (OR 3.04, P = 0.33) are ineffective. US-guided FNA (sensitivity/specificity: 95.24%/97.92%) is effective in the treated neck, though with high non-diagnostic rate (29.69%). US-guided CNB (sensitivity/specificity: 84.62%/100%) is also effective, though with low negative predictive value (62.5%). Overall, US with US-guided FNA/CNB are still effective diagnostic tools for neck nodal recurrence surveillance.

First records of the sycamore lace bug, Corythucha ciliata (Say), in Greece

In late August 1988, the author noticed the presence of Corythucha ciliata (Say) (Hemiptera: Tingidae) in many plane trees of the following locations of northwestern Greece: 1) City of Kastoria, on 22.VIII.1988, along the coastal road of the city’s peninsula in Lake Orestias. Along this road, trees near the Panaghia Mavriotissa church were heavily infested, while trees further away were less so. Infested trees were also noticed along the quay of the northern end of the city. 2) Zagori, Epirus, on 24. VIII.1988, on the banks of the river Voidomatis, where the river meets the road between the villages Aristi and Papingo. The degree of infestation varied between adjacent trees. 3) Zagori, Epirus, on 25.VIII.1988, the single plane tree in the middle of the square of the village Eptahori. 4) City of Yannina, on 26. VIII. 1988, several single trees in the Kastro section of the city and also trees along the banks of the lake bordering the city. As heavily infested were recorded trees having most of their leaves chlorotic in the largest part of their laminae. On the underside of leaves that could be reached from the ground live adults, exuviae of immature stages and dark sports typical of excrement and of oviposition sites of Tingidae were found. On certain leaves more than 10 live adults per leaf were counted in Kastoria and Yannina. The identity of the species was determined by the author on adult specimens from Kastoria preserved dry and in ethanol. The fact that the infested locations were tens of kilometers apart and at considerably differ ent altitudes, leads to the conclusion that C. ciliata must have crossed the Greek northwest­ern border not less than two years ago. It is suspected that the insect entered Greece by natural spread from neighboring Albania. Examination by the author of plane trees in towns and villages of the Pella and Kilkis prefectures near the Yugoslavian border, showed no infestation. C. ciliata is of nearctic origin. In the northeastern and northwestern United States it is a pest of sycamore, Platanus occidentalis L., which is its preferred host plant, but also feeds on ash, hickory and also on mulberry. In Europe the host plants of preference are Platanus X acerifolia (Afton) Willd. and P. orientalis L., while such other broad-leaved trees as Brussonetia pap•rifera and ash are also reported as able to support the insect. The insect entered Europe and was noted first in Italy in 1964. Its spread was rather rapid, so that by 1986 it had spread to all the regions of Italy. In 1976 chemical control tests against it were re­ported from Hungary. Its presence in Yugoslavia was reported in 1972, in France in 1977, in Spain in 1981, in Switzerland in 1983 and in Austria in 1984. It is considered one of the three most important insects infesting the leaves of plane trees in Italy and generally very destructive. The adult insect is approximately 3 to 3.5 mm long and has reticulate front wings and reticulate expansions of the pronotum. The pronotum is yellowish, largely expanded on the sides which are transparent, and has a median vesicated process. The front wings are subquadrangular and have a proximal vesica which is globular and more or less smoky to­wards its internal margin. Two to three generations per year have been reported in Italy, same as in the northeastern United States. Hibernation takes place in the adult stage, mostly under loose bark at the basal part of the trunk or in other protected places nearby. In spring, the adults move to the young leaves, where they lay their eggs on the under side of the blade where the immature stages feed and develop and the long-lived adults re­main feeding and reproducing. The feeding punctures cause chlorosis which starts from the basal part of the leaf and may expand to almost the whole leaf. On the underside of leaves, where the insect lives in colonies, there are usually numerous small dark spots. Heavily infested species of Platanus, in addition to extensive yellowing, may undergo premature leaf drop. In Italy and especially in urban areas, C. ciliata continues to cause concern because of the weakening of plane trees which predis­poses them to attacks by other enemies. There is no doubt that the spread of C. ciliates in Greece will also be fairly rapid. The authorities should take advantage of the extensive work done in Italy, to further develop effective and ecologically sound control measures. Determining the resistance to the insect of Plalanus stock available in Greece should be among the projects to be encouraged.