Synthetic plasma edge diagnostics for EMC3-EIRENE, highlighted for Wendelstein 7-X.

Interpretation of spectroscopic measurements in the edge region of high-temperature plasmas can be a challenge since line of sight integration effects make direct interpretation in terms of quantitative, local emission strengths often impossible. The EMC3-EIRENE code-a 3D fluid edge plasma and kinetic neutral gas transport code-is a suitable tool for full 3D reconstruction of such signals. A versatile synthetic diagnostic module has been developed recently which allows the realistic 3D setup of various plasma edge diagnostics to be captured. We highlight these capabilities with two examples for Wendelstein 7-X (W7-X): a visible camera for the analysis of recycling, and a coherent-imaging system for velocity measurements.

Design and characterization of a prototype divertor viewing infrared video bolometer for NSTX-U.

The InfraRed Video Bolometer (IRVB) is a powerful tool to measure radiated power in magnetically confined plasmas due to its ability to obtain 2D images of plasma emission using a technique that is compatible with the fusion nuclear environment. A prototype IRVB has been developed and installed on NSTX-U to view the lower divertor. The IRVB is a pinhole camera which images radiation from the plasma onto a 2.5 µm thick, 9 × 7 cm2 Pt foil and monitors the resulting spatio-temporal temperature evolution using an IR camera. The power flux incident on the foil is calculated by solving the 2D+time heat diffusion equation, using the foil's calibrated thermal properties. An optimized, high frame rate IRVB, is quantitatively compared to results from a resistive bolometer on the bench using a modulated 405 nm laser beam with variable power density and square wave modulation from 0.2 Hz to 250 Hz. The design of the NSTX-U system and benchtop characterization are presented where signal-to-noise ratios are assessed using three different IR cameras: FLIR A655sc, FLIR A6751sc, and SBF-161. The sensitivity of the IRVB equipped with the SBF-161 camera is found to be high enough to measure radiation features in the NSTX-U lower divertor as estimated using SOLPS modeling. The optimized IRVB has a frame rate up to 50 Hz, high enough to distinguish radiation during edge-localized-modes (ELMs) from that between ELMs.

Preliminary design of a tangentially viewing imaging bolometer for NSTX-U.

The infrared imaging video bolometer (IRVB) measures plasma radiated power images using a thin metal foil. Two different designs with a tangential view of NSTX-U are made assuming a 640 × 480 (1280 × 1024) pixel, 30 (105) fps, 50 (20) mK, IR camera imaging the 9 cm × 9 cm × 2 µm Pt foil. The foil is divided into 40 × 40 (64 × 64) IRVB channels. This gives a spatial resolution of 3.4 (2.2) cm on the machine mid-plane. The noise equivalent power density of the IRVB is given as 113 (46) µW/cm2 for a time resolution of 33 (20) ms. Synthetic images derived from Scrape Off Layer Plasma Simulation data using the IRVB geometry show peak signal levels ranging from ∼0.8 to ∼80 (∼0.36 to ∼26) mW/cm2.

Mitigation of Alfvén activity in a tokamak by externally applied static 3D fields.

The application of static magnetic field perturbations to a tokamak plasma is observed to alter the dynamics of high-frequency bursting Alfvén modes that are driven unstable by energetic ions. In response to perturbations with an amplitude of δB/B∼0.01 at the plasma boundary, the mode amplitude is reduced, the bursting frequency is increased, and the frequency chirp is smaller. For modes of weaker bursting character, the magnetic perturbation induces a temporary transition to a saturated continuous mode. Calculations of the perturbed distribution function indicate that the 3D perturbation affects the orbits of fast ions that resonate with the bursting modes. The experimental evidence represents an important demonstration of the possibility of controlling fast-ion instabilities through "phase-space engineering" of the fast-ion distribution function, by means of externally applied perturbation fields.

Effect of quasihelical symmetry on trapped-electron mode transport in the HSX stellarator.

This Letter presents theory-based predictions of anomalous electron thermal transport in the Helically Symmetric eXperiment stellarator, using an axisymmetric trapped-electron mode drift wave model. The model relies on modifications to a tokamak geometry that approximate the quasihelical symmetry in the Helically Symmetric eXperiment (particle trapping and local curvature) and is supported by linear 3D gyrokinetic calculations. Transport simulations predict temperature profiles that agree with experimental profiles outside a normalized minor radius of rho>0.3 and energy confinement times that agree within 10% of measurements. The simulations can reproduce the large measured electron temperatures inside rho<0.3 if an approximation for turbulent transport suppression due to shear in the radial electric field is included.

Primary adenocarcinoma of cervical esophagus.

Most upper esophageal malignancies are squamous cell carcinomas, rarely adenocarcinomas arising from Barrett's esophagus and very rarely adenocarcinomas from heterotopic gastric mucosa without evidence of Barrett's especially in the cervical part of the esophagus. We report a case of adenocarcinoma of the polypoid type in the upper esophagus (cervical esophagus) arising from ectopic gastric mucosa, in a 60 year-old man who presented with progressive dysphagia. Accurate diagnosis by esophagogram revealed a large mass in the cervical esophagus; CAT scan showed intraluminal mass at the level of thoracic inlet, esophagogastroscopy showed a fleshy polyp (3.2cm x 3.0cm) at 20 cm from the incisors with a biopsy confirming moderately differentiated adenocarcinoma with no evidence of Barrett's esophagus. Through a left cervical approach and resection of medial third of clavicle, the tumor was removed by partial esophagectomy followed by lymph node dissection, and proved to be T1NOMO, stage I (AJCC staging 6th ed.). Post operatively, the patient received chemoradiation with no evidence of recurrence or metastasis in six years of follow up. It seems this tumor has a much better prognosis than adenocarcinomas arising from Barrett's. To our knowledge only 19 cases have been reported in literature so far.

Thirty-eight-year evaluation of a surgical technique to protect the external branch of the superior laryngeal nerve during thyroidectomy.

The purpose of this study is to evaluate a surgical technique for the preservation of the function of the external branch of the superior laryngeal nerve (EBSLN) during total thyroid lobectomy and total thyroidectomy. Permanent injury to this nerve can be a disaster, especially in singers and professional speakers who depend on control of pitch, and a clear and forceful voice. Voice changes may be either obvious or subtle. For better voice analysis, a detailed questionnaire is necessary. Thus, the evaluation in this study is based on laryngoscopy of 934 nerves in 675 patients and detailed subjective voice evaluation of 66 patients during the last 2 years of the study. There are 2 surgical principles. First, the EBSLN is not routinely exposed; the distal 1.5 to 2.0 cm (critical area) of the superior thyroid vessels are carefully dissected, exposed, and ligated, preferably independently. Careful observation ensures that the EBSLN is not included in the ligature. Second, the ultimate evaluation of the surgical technique is the effect of voice changes on the patient's lifestyle. Laryngoscopy of 934 nerves found bowing, temporary in 4 patients and permanent in 1 patient (limited follow-up). Of the 66 patients with voice evaluations, 14 had changes: 9 had temporary changes, while 5 had permanent changes. In these 14 patients, voice changes had no effect on lifestyle in 13, and the effects were indeterminate in 1 (unavailable for follow-up). The estimated deleterious effect of voice changes on lifestyle is no greater than 1.5% of the 66 patient responders.

Total thyroidectomy for Graves' disease.

BACKGROUND: Therapeutic options for treatment of hyperthyroidism caused by Graves' disease remain controversial. There are three main options: thiourea drugs, radioactive iodine ablation, and thyroidectomy. Each treatment has significant advantages and potential problems. METHODS: The present study is a retrospective analysis of our experience with total thyroidectomy in Graves' disease. Sixty-two patients underwent this procedure in 11 years' time and were followed for a minimum of 2 years after surgery. All had measurement of total thyroxine, T3 uptake, and radioactive iodine (RAI) uptake and scanning. Sixty-three percent of all patients had some element of hyperthyroid eye signs. All patients were rendered euthyroid with pharmacologic therapy prior to surgery. Postoperatively, the patients were evaluated for improvement in eye signs, incidence of recurrent laryngeal nerve injury, and hypoparathyroidism. RESULTS: None of the patients in this study have developed recurrent hyperthyroidism. All patients are maintained on levothyroxine. None of our patients incurred bilateral vocal cord paralysis. One patient (1.6%) demonstrated an immobile vocal cord more than 1 year following surgery. Ten patients (16%) demonstrated impaired mobility of one vocal cord in the immediate postoperative period. Nine of these patients recovered full vocal cord mobility within 6 months after surgery. Only one patient (1.6%) still required calcium and vitamin D therapy 1 year following surgery. However, in the immediate postoperative period, 23 patients (37%) required supplemental calcium and vitamin D. In 12 patients, calcium and vitamin D was discontinued within 1 month. In an additional 6 patients, calcium and vitamin D were discontinued within 4 months; 3 patients, within 6 months; and 1 patient, within 12 months after surgery. Incidental papillary carcinoma was found in 3 patients (5%). CONCLUSIONS: Total thyroidectomy for Graves' disease is an effective and safe therapy. When performed by an experienced head and neck surgeon, it carries a low morbidity rate. It should be presented to patients as a therapeutic option within the context of a comprehensive discussion of the risks and benefits of radioactive iodine, pharmacologic therapy, and surgery.

Improved survival with preoperative chemotherapy followed by resection uncompromised by tumor response for advanced squamous cell carcinoma of the head and neck.

BACKGROUND: A total of 93 patients were treated with one of two preoperative chemotherapy regimens over a 15-year period. The study supports the importance of strict adherence to guidelines for ablative surgery. METHODS: A single surgeon performed the surgery and evaluated each patient prior to treatment. The extent of the planned operation was documented. RESULTS: The 5-year absolute survival of 88 patients who completed the protocol was estimated at 55%. The 40 cisplatin/5-fluorouracil-treated patients exhibited a significantly better outcome than the 48 cisplatin/bleomycin-treated patients (76% versus 43%, respectively). Comparison of a subset of 37 patients with a matched group from the standard control arm of the Head and Neck Contracts Program demonstrated a statistically significant improvement in overall survival over standard treatment. CONCLUSIONS: These data suggest that strict adherence to preoperative chemotherapy planning of ablative uncompromised surgery contribute to improved survival. Selective rather than routine postoperative radiotherapy may be advantageous.

Access to the superior mediastinum.

Surgical access for diseases that involve the superior mediastinum can be achieved without thoracotomy by utilizing the suprasternal approach with extension of the head and neck and transection of the interclavicular ligament, median sternotomy, resection of the medial third to one half of the clavicle, or resection of the manubrium sterni. There has been minimal morbidity and no operative or postoperative mortality in a review of 53 consecutive patients. There has been no significant disability. Combined with exposure at the base of the neck, the access to the superior mediastinum is good to excellent.

Surgery vs chemotherapy plus surgery for carcinoma of the head and neck.

We reviewed the results of standard therapy (surgery +/- radiation therapy) in 66 patients with advanced resectable head and neck cancer treated between 1984 and 1988 and compared them with a "historical" group of similar resectable patients treated between 1978 and 1984, by induction chemotherapy followed by standard therapy. The median disease-free survival of patients treated by surgery was 18 months, whereas it had not been reached in those receiving chemotherapy. When 2-year disease-free survival was compared according to stage and site, patients receiving chemotherapy fared better. The recurrence rate of all patients receiving chemotherapy was less than half of those receiving standard treatment only. A higher percentage of patients receiving chemotherapy survived their original tumor, only to die of second malignancies, most of these occurring elsewhere in the aerodigestive tract.

Surgery for advanced thyroid malignancy.

Advanced thyroid malignancy can occur early in the course of the disease, or as late as 20 to 25 years after the initial diagnosis. The basic treatment is total thyroidectomy with central node dissection regardless of the histologic type. the nonresectable disease is treated with 131I if the tumor has iodine uptake. Further ablative surgery for resectable disease is governed by location and histologic cell type. Otherwise external radiation and chemotherapy (Adriamycin) is used. Anaplastic, primary squamous cell, and pure papillary and some predominantly papillary carcinomas and some Hürthle cell carcinomas do not have 131I uptake and fall into this latter category. The surgeon must be aware of this problem in the noniodine uptake tumors and take special care to remove all surgically resectable disease.

Complications in management of thyroid cancer.

There are a number of complications related to the management of thyroid carcinoma, some due to the natural history of the disease regardless of its cell type and all too many which are iatrogenic. Three of these complications will be discussed: 1) airway problems, 2) related photation aspects, and 3) hypoparathyroidism.

Controversies in the diagnosis and treatment of early carcinoma of the larynx.

Patients in whom the diagnosis of early carcinoma of the larynx is made and treated as outlined below have a good to excellent outlook (from 85 to 95% survival for glottic lesions). Metastases from lesions of the free edge of the vocal cord usually do not occur because of the paucity of lymphatics, whereas lesions of the supraglottis are more apt to metastasize to regional lymph nodes and local spread. The subglottic area on the other hand by in large has a more ominous prognosis. Carcinoma in situ is treated mainly by endoscopic surgery, whereas T1 lesions of the glottis can either be treated by surgery or radiation with comparable results. This author prefers conservation surgery for the majority of T1 lesions. Radiotherapy is utilized for selected patients with T1 glottic lesions.

The treatment of metastatic thyroid disease.

1. Removal of all resectable disease commensurate with reasonable morbidity and mortality is the initial treatment of all thyroid carcinoma. 2. Patients with no evidence of recurrent metastatic well-differentiated thyroid carcinoma should be placed on suppressive doses of Synthroid. 3. 131I is utilized for nonresectable and for distant metastatic well-differentiated thyroid carcinoma. External radiation therapy and chemotherapy are utilized in recurrent or metastatic thyroid carcinomas that do not concentrate 131I.

Long-term follow-up of chemotherapy in advanced head and neck cancer.

We treated 94 patients with advanced head and neck cancer with a combined-modality protocol that included induction chemotherapy followed by surgery with and without radiotherapy. With a minimum follow-up of 3 1/2 years, 33 (35%) of the patients were alive and disease free. Thirty (32%) of the patients died of recurrent head and neck cancer. Complete response to chemotherapy and initial tumor bulk correlated with prolonged disease-free survival. Site of disease had no effect. There appeared to be no advantage to the use of routine postoperative radiotherapy in these advanced tumors.