Soft X-Ray Second Harmonic Generation as an Interfacial Probe.

Nonlinear optical processes at soft x-ray wavelengths have remained largely unexplored due to the lack of available light sources with the requisite intensity and coherence. Here we report the observation of soft x-ray second harmonic generation near the carbon K edge (∼284 eV) in graphite thin films generated by high intensity, coherent soft x-ray pulses at the FERMI free electron laser. Our experimental results and accompanying first-principles theoretical analysis highlight the effect of resonant enhancement above the carbon K edge and show the technique to be interfacially sensitive in a centrosymmetric sample with second harmonic intensity arising primarily from the first atomic layer at the open surface. This technique and the associated theoretical framework demonstrate the ability to selectively probe interfaces, including those that are buried, with elemental specificity, providing a new tool for a range of scientific problems.

Passive Linearization of the Magnetic Bunch Compression Using Self-Induced Fields.

In linac-driven free-electron lasers, colliders, and energy recovery linacs, a common way to compress the electron bunch to kiloampere level is based upon the implementation of a magnetic dispersive element that converts particle energy deviation into a path-length difference. Nonlinearities of such a process are usually compensated by enabling a high harmonic rf structure properly tuned in amplitude and phase. This approach is however not straightforward, e.g., in C-band and X-band linacs. In this Letter we demonstrate that the longitudinal self-induced field excited by the electron beam itself is able to linearize the compression process without any use of high harmonic rf structure. The method is implemented at the FERMI linac, with the resulting high quality beam used to drive the seeded free-electron laser during user experiments.

The FERMI free-electron lasers.

FERMI is a seeded free-electron laser (FEL) facility located at the Elettra laboratory in Trieste, Italy, and is now in user operation with its first FEL line, FEL-1, covering the wavelength range between 100 and 20 nm. The second FEL line, FEL-2, a high-gain harmonic generation double-stage cascade covering the wavelength range 20-4 nm, has also completed commissioning and the first user call has been recently opened. An overview of the typical operating modes of the facility is presented.

Experimental demonstration of electron longitudinal-phase-space linearization by shaping the photoinjector laser pulse.

Control of the electron-beam longitudinal-phase-space distribution is of crucial importance in a number of accelerator applications, such as linac-driven free-electron lasers, colliders and energy recovery linacs. Some longitudinal-phase-space features produced by nonlinear electron beam self- fields, such as a quadratic energy chirp introduced by geometric longitudinal wakefields in radio-frequency (rf) accelerator structures, cannot be compensated by ordinary tuning of the linac rf phases nor corrected by a single high harmonic accelerating cavity. In this Letter we report an experimental demonstration of the removal of the quadratic energy chirp by properly shaping the electron beam current at the photoinjector. Specifically, a longitudinal ramp in the current distribution at the cathode linearizes the longitudinal wakefields in the downstream linac, resulting in a flat electron current and energy distribution. We present longitudinal-phase-space measurements in this novel configuration compared to those typically obtained without longitudinal current shaping at the FERMI linac.

Characterisation of microbunching instability with 2D Fourier analysis.

The optimal performance of high-brightness free-electron lasers (FELs) is limited by the microbunching instability, which can cause variations in both the slice energy spread and longitudinal profile of electron beams. In this paper, we perform 2D Fourier analysis of the full bunch longitudinal phase space, such that modulations in both planes can be studied simultaneously. Unlike the standard 1D analysis, this method is able to reveal modulations in a folded phase space, which would otherwise remain uncovered. Additionally, the plasma oscillation between energy and density modulations is also revealed by this method. The damping of the microbunching instability, through the use of a laser heater, is also analysed with this technique. We confirm a mitigation of the amplitude of modulation and a red-shift of the microbunching frequency as the energy spread added increases. As an outcome of this work, a systematic experimental comparison of the development of the instability in the presence of different compression schemes is here presented for the first time.

The German Hodgkin Study Group risk model is useful for Hodgkin lymphoma patients receiving radiotherapy after autologous stem cell transplant.

PURPOSE: To apply the German Hodgkin Study Group (GHSG) risk model in patients with recurrent/refractory Hodgkin lymphoma receiving involved-field radiotherapy after autologous stem cell transplantation. MATERIAL AND METHODS: The study consisted in the retrospective analysis of 30 consecutive patients with recurrent/refractory Hodgkin lymphoma who received involved-field radiotherapy after autologous stem cell transplantation. Our policy was of adding involved-field radiotherapy for patients with positive PET scan before autologous stem cell transplantation (23 out of 30 patients, 77%), and/or irradiating sites of bulky disease at relapse (11 out of 30 patients, 37%). Patients were stratified into four risk groups according to the presence of the five clinical risk factors identified by the GHSG; (1) stage IV disease; (2) time to relapse≤3 months; (3) ECOG-PS≥1; (4) bulk≥5cm; and (5) inadequate response to salvage chemotherapy. RESULTS: The median interval from autologous stem cell transplantation to involved-field radiotherapy was 3 months (range, 1-7 months), and the median involved-field radiotherapy dose was 35Gy (range, 12-40Gy). At a median follow-up of 35 months (range, 1-132 months), the 2-year progression-free survival in the entire series was 60%. When examining the four different GHSG risk groups, the progression-free survival rate at 2 years was 86%, 83%, 50%, and 36% for patients with score=0, score=1, score=2, and score=3 to 5, respectively (P=0,01). Among the 12 patients havingat leastthree risk factors who underwent thoracic involved-field radiotherapy, three (25%) developed pneumonitis. CONCLUSION: The adoption of the GHSG risk model at the time of recurrence/progression is a useful prognostic tool to select patients with Hodgkin lymphoma for consolidative involved-field radiotherapy after autologous stem cell transplantation.

Nanoscale transient gratings excited and probed by extreme ultraviolet femtosecond pulses.

Advances in developing ultrafast coherent sources operating at extreme ultraviolet (EUV) and x-ray wavelengths allow the extension of nonlinear optical techniques to shorter wavelengths. Here, we describe EUV transient grating spectroscopy, in which two crossed femtosecond EUV pulses produce spatially periodic nanoscale excitations in the sample and their dynamics is probed via diffraction of a third time-delayed EUV pulse. The use of radiation with wavelengths down to 13.3 nm allowed us to produce transient gratings with periods as short as 28 nm and observe thermal and coherent phonon dynamics in crystalline silicon and amorphous silicon nitride. This approach allows measurements of thermal transport on the ~10-nm scale, where the two samples show different heat transport regimes, and can be applied to study other phenomena showing nontrivial behaviors at the nanoscale, such as structural relaxations in complex liquids and ultrafast magnetic dynamics.

Coherent THz Emission Enhanced by Coherent Synchrotron Radiation Wakefield.

We demonstrate that emission of coherent transition radiation by a ∼1 GeV energy-electron beam passing through an Al foil is enhanced in intensity and extended in frequency spectral range, by the energy correlation established along the beam by coherent synchrotron radiation wakefield, in the presence of a proper electron optics in the beam delivery system. Analytical and numerical models, based on experimental electron beam parameters collected at the FERMI free electron laser (FEL), predict transition radiation with two intensity peaks at ∼0.3 THz and ∼1.5 THz, and extending up to 8.5 THz with intensity above 20 dB w.r.t. the main peak. Up to 80-µJ pulse energy integrated over the full bandwidth is expected at the source, and in agreement with experimental pulse energy measurements. By virtue of its implementation in an FEL beam dump line, this work promises dissemination of user-oriented multi-THz beamlines parasitic and self-synchronized to EUV and x-ray FELs.

Stereotactic body radiation therapy and intensity modulated radiation therapy induce different plasmatic cytokine changes in non-small cell lung cancer patients: a pilot study.

PURPOSE: To assess kinetics of plasmatic cytokines during radiation therapy (RT) for locally advanced and early-stage non-small cell lung cancer (NSCLC). METHODS: This prospective study was conducted on 15 early-stage NSCLC underwent to extreme hypofractionated regimen (52 Gy in 8 fractions) with stereotactic body RT (SBRT), and 13 locally advanced NSCLC underwent to radical moderated hypofractionated regimen (60 Gy in 25 fractions) with intensity modulated RT (IMRT). For patients undergoing SBRT, peripheral blood samples were collected on the first day of SBRT (TFd), the last day (TLd) and 45 days (T45d) after the end of SBRT. For patients undergoing IMRT, blood samples were collected at: TFd, 2 weeks (T2w), 4 weeks (T4w), TLd, and T45d. The following cytokines were measured: IL-1, IL-1ra, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12, IL-13, IL-15, IL-17A, EGF, FGF-2, INF-γ, MIP-1α, MIP-1ß, TGF-α, TNF-α, and VEGF. Cytokine levels measured in different RT time and compared. RESULTS: No difference in baseline levels of cytokines was documented between patient radiation approaches (except for MIP-1α). For SBRT patients, a mean reduction of IL-10 and IL-17 plasma level was documented between TLd and TFd, respectively (p < 0.05). For IMRT patients, a statistically significant (p < 0.05) mean plasma level reduction was documented between T4w and TFd for all the following cytokines: IL-1, IL-1ra, IL-2, IL-12, FGF-2, MIP-1α, MIP-1ß, TGF-α, TNF-α, VEGF. CONCLUSIONS: SBRT and IMRT induce different plasmatic cytokine changes in NSCLC patients, supporting hypothesis that RT regimes of dose schedules and techniques have different impacts on the host immune response.

Etoposide (VP-16-213) in malignant brain tumors: a phase II study.

Twenty-two consecutive patients with recurrent malignant brain tumors after radiation therapy and systemic combination chemotherapy with BCNU and vincristine, four of whom were not evaluable due to early death, were treated with etoposide (VP-16-213) (50-100 mg/m2 for five days every three weeks). Response, defined as improvement in both clinical examination and computed tomography scan in absence of glucocorticoids dosage increase, was observed in three (17%) of 18 evaluable patients, lasting greater than 21, seven, and two months, respectively. Six additional patients had stable disease for greater than 10, seven, four, four, three, and two months: all of them had improvement of clinical symptoms but no variation in their scans. Overall median survival from the start of VP-16-213 was 4.5 months (range, 1-23 + months), whereas patients with response or stable disease had a median survival of eight months. Overall, treatment was well tolerated. In 10 patients concomitant plasma and cerebrospinal fluid samples were evaluated with a high-performance liquid chromatographic method for drug assay. The concentration of VP-16-213 in cerebrospinal fluid was less than 1% that found in plasma, even in the two patients with response. The activity of etoposide in patients with malignant, lomustine-vincristine-resistant brain tumors suggests an interesting potential use for this drug.

Dynamics and stabilization of the Elettra storage-ring free-electron laser.

The ultimate performance of a storage-ring free-electron laser in terms of light stability and extracted power depends on the possibility of simultaneously controlling the electron-beam and laser dynamics. As a preliminary requirement, the level of longitudinal and transverse electron-beam stability must be high enough to guarantee the laser start-up and growth. This is usually obtained by means of dedicated feedback systems. Once such a requirement is satisfied, the possibility of establishing and maintaining a continuous-wave operation mode finally resides in a deep understanding of the strongly coupled laser-electrons dynamics. For this purpose, we have developed a simple theoretical model which has been proved to be able to provide insight into the evolution of the laser intensity. In this framework, we have also proposed the possibility of utilizing a derivative closed-loop feedback to create or enlarge the region of stable signal. A feedback of this type has been implemented on the Elettra storage-ring free-electron laser. The obtained results, which fully confirm our predictions, are discussed in this paper.

Normal tissue complication probability models for severe acute radiological lung injury after radiotherapy for lung cancer.

PURPOSE: To derive Normal Tissue Complication Probability (NTCP) models for severe patterns of early radiological radiation-induced lung injury (RRLI) in patients treated with radiotherapy (RT) for lung tumors. Second, derive threshold doses and optimal doses for prediction of RRLI to be used in differential diagnosis of tumor recurrence from RRLI during follow-up. METHODS AND MATERIALS: Lyman-EUD (LEUD), Logit-EUD (LogEUD), relative seriality (RS) and critical volume (CV) NTCP models, with DVH corrected for fraction size, were used to model the presence of severe early RRLI in follow-up CTs. The models parameters, including α/ß, were determined by fitting data from forty-five patients treated with IMRT for lung cancer. Models were assessed using Akaike information criterion (AIC) and area under receiver operating characteristic curve (AUC). Threshold doses for risk of RRLI and doses corresponding to the optimal point of the receiver operating characteristic (ROC) curve were determined. RESULTS: The α/ßs obtained with different models were 2.7-3.2 Gy. The thresholds and optimal doses curves were EUDs of 3.2-7.8 Gy and 15.2-18.1 Gy with LEUD, LogEUD and RS models, and µd of 0.013 and 0.071 with the CV model. NTCP models had AUCs significantly higher than 0.5. Occurrence and severity of RRLI were correlated with patients' values of EUD and µd. CONCLUSIONS: The models and dose levels derived can be used in differential diagnosis of tumor recurrence from RRLI in patients treated with RT. Cross validation is needed to prove prediction performance of the model outside the dataset from which it was derived.

Evaluation of hospital care in a radiotherapy department in north-eastern Italy.

Assessment of the quality of care and patients' satisfaction has become an increasingly needed area of research. The present study investigated various qualitative and quantitative aspects of provision of care and interaction between cancer outpatients and medical and nursing staff within a radiotherapy department in Pordenone, north-eastern italy. A total of 368 outpatients were contacted: 258 completed the questionnaire (response rate 70%). No difference emerged between respondents and non-respondents as concerning age, sex, marital status, clinical stage, cancer type and reason for referral. Significant differences were found for education and type of work, white collar and better educated patients being more frequent among respondents. Most of the patients reported good or very good levels of satisfaction with major aspects of care provision and relationship with medical and nursing staff. Length of time spent in various administrative procedures, cost of the therapy and change of attending physician in different examinations were the issues commented upon relatively less favourably. Reported waiting time for each medical examination exceeded 1 hour in approximately half of the patients. Improvement in hospital services constituted the priority, according to male patients. Public transportation concerned most women's and elderly patients' attention. Among elderly patients, the need for better provision of care at home was also deeply felt.

The effect of timing of vincristine administration during a course of fractionated radiotherapy in a mouse carcinoma.

It has been previously shown that the uptake of 3H-vincristine by the NT carcinoma tumour in CBA mice can vary by a factor of 3 during a course of fractionated radiotherapy (2 Gy day-1, 5 day week-1, for 5 weeks). Here the effect of therapeutic doses of vincristine given at times of either maximum or minimum uptake has been investigated. The results show that whereas vincristine alone has a dose-related effect on this tumour, when given in combination with fractionated radiation it is only effective if administered during the first few fractions. It does not seem to matter whether it is given at times of maximum or minimum uptake. It is concluded that vincristine either exacerbates the radiation-induced vascular damage so that drug extravasation is reduced or that it causes a shift in the time of appearance of the peaks and troughs of uptake. The possibility that radiation-induced resistance to vincristine may have played a part in the results is also discussed.

Cisplatin and etoposide versus cyclophosphamide, epirubicin and vincristine in small cell lung cancer: a randomised study.

From September 1986 until December 1991, 139 patients with histologically-proven small cell lung cancer, age < 75 years, performance status > 40, absence of brain metastases and no previous treatment, were randomised to receive either CEV cyclophosphamide 1000 mg/m2 intravenous (i.v.), epirubicin 70 mg/m2 i.v., vincristine 1.2 mg/m2 i.v., every 3 weeks or PE (cisplatin 20 mg/m2 i.v. and etoposide 75 mg/m2 i.v. for 5 consecutive days, every 3 weeks) for six cycles. After three cycles, responding patients received radiotherapy to the chest (45 Gy/15 sessions) and to the brain (30 Gy/10 sessions--only in patients with limited disease achieving complete remission). 3 patients were ineligible. Patient characteristics included (CEV/PE) total number 66/70, median age 60/61 years, median performance status 80/80, extended disease 33/48 cases (P = 0.04). In evaluable patients, 42/62 (67.7%) responded to CEV while 42/58 (72.4%) responded to PE (P = non-significant); respective complete response rates were 16.1 and 29.3% (P = non-significant) and respective complete response rates in patients with extended disease were 9.4 and 28.9% (P = 0.03). Median survival was 10.5 months, without significant differences in the two treatment arms, even after adjustment for stage. PE was less well tolerated than CEV. Although PE is more active than CEV in certain subsets of patients, its apparent inability to improve survival in this and in other studies questions its routine use in small cell lung cancer.

Paclitaxel as a radiosensitiser: a proposed schedule of administration based on in vitro data and pharmacokinetic calculations.

Paclitaxel is efficacious against many human cancers. Because it blocks cells at the radiosensitive G2-M interface, paclitaxel has been investigated as a radiosensitiser. The results have been equivocal and somewhat contradictory. It is impossible to obtain proper pharmacokinetic calculations, aimed at obtaining maximum cytotoxicity and/or radiosensitisation, without knowing (i) how long the drug must be in contact with the cells, (ii) how long the effect lasts after the drug is removed from the cellular environment, (iii) whether the drug acts as a radiosensitiser even when, like cis-platinum, it is added after the radiation and (iv) what the minimum quantity of drug in the cellular environment is required for both chemotoxicity and radiosensitisation. The present work addresses the above questions. Two radioresistant cell lines of human origin were used, A375 melanoma and S549 lung carcinoma, in a clonogenic assay where only colonies with 50 or more cells were counted. For the irradiation, 6 MV X-rays were used. Any G2-M block was quantified by cell cycle kinetics analysis. From the results, a simulation of pharmacokinetics was conducted to calculate the schedule of administration of paclitaxel most likely to achieve and maintain significant chemotoxocity and radiosensitisation. The minimum concentration of paclitaxel for measurable cytotoxicity was 3 nM for both cell lines, but the drug was more toxic to the A549 cells. The minimum concentration for measurable radiosensitisation was 3 nM for A375 and approximately 0.1 nM for A549, but whereas above 3 nM the radiosensitivity increased in A375, it decreased above 1 nM for A549. A minimum of 18 h incubation with the drug was necessary for measurable effects and the radiosensitising effects were lost soon after its removal. There was no radiosensitisation if paclitaxel was added after the radiation, and, at the minimum effective concentrations, it caused only a minor and transient G2-M block. The pharmacokinetic calculations predict that 15 mg/m2 paclitaxel given as a 1 h infusion 5 days/week for 3 weeks during the radiotherapy should achieve both cytotoxicity and radiosensitisation. The mechanism of radiosensitisation by paclitaxel at the concentrations suggested by our results does not appear to be via a G2-M block and is probably concentration dependent. The results imply that low-dose, daily infusions of paclitaxel for as long as possible during a course of radiotherapy are more likely to result in radiosensitisation and prolonged cytotoxicity than high-dose infusions given once a week.

Multimodal treatment of locally advanced transitional cell bladder carcinoma in elderly patients.

22 patients with locally advanced (T3-T4, M0) transitional cell bladder carcinoma, age greater than 70 years, with medical contraindication or refusal of radical cystectomy, were treated following an ample transurethral resection (TUR), with three chemotherapy cycles. Each cycle consisted of 5-fluorouracil 500 mg/m2 intravenously (i.v.) on days 1 and 8, epirubicin 60 mg/m2 i.v. on day 1 and cisplatin 50 mg/m2 i.v. on day 1. Cycles were repeated every 3 weeks. Subsequently, patients were submitted to a repeat TUR on the area of the initial neoplasm. At computed tomography (CT) scan evaluation, response rate to chemotherapy was 54.5%, with two complete responses. No residual disease (R0) at postchemotherapy TUR was encountered in 8 cases (36%), and microscopic disease (R1) in 4 cases (18%). Median duration of complete responses (R0) was 13.5 months (range 7-57+). Radiation therapy was carried out in 12/14 patients with residual disease at repeat TUR. Overall median duration of response was 10.2 months, while overall actuarial median survival was 11.6 months. Four-year survival was 29%. The approach described was feasible. The chemotherapy regimen employed was not as active as current regimens used in younger patients. The search for more active regimens which are tolerable by the elderly is important.

Reirradiation and lomustine in patients with relapsed high-grade gliomas.

PURPOSE: The aim of this study was to evaluate the toxicity, response, and survival of patients with relapsed high-grade gliomas after radiation therapy (RT) combined with lomustine (CCNU). METHODS AND MATERIALS: Thirty-one patients with relapsed gliomas at least 6 months after completion of RT were reirradiated. Twenty-four patients had a pathological diagnosis of high-grade gliomas, whereas 7 had a radiological diagnosis of relapsed malignant gliomas. The study focused on patients with high-grade relapsed gliomas. A total dose of 34.5 Gy was delivered in 23 fractions over 4.5 weeks. Oral administration of CCNU (130 mg/m2) was begun at the same time as RT, and was repeated every 6 weeks until disease progression, or up to 12 courses. RESULTS: Twelve of 24 patients had surgery before RT plus CCNU treatment. Median interval between RT courses was 14 months (range 6-73). All patients received a complete course of RT, and 22 of 24 patients received at least one course of CCNU. Objective responses were seen in 14 evaluable patients: 3 with partial response, 5 with stable disease, and 6 with progressive disease. Duration of partial response was 20, 9, and 8 months. Median time to progression and overall survival from the onset of retreatment were 8.4 months (range 1-22) and 13.7 months (range 1-63+), respectively. One case of G4 thrombocytopenia was observed. Five patients had G1 or G2 leucopenia and 3 patients had G3 leucopenia. Moderate nausea and vomiting were reported in 4 patients. One patient, after one course of CCNU, refused further chemotherapy. No significant difference in survival from relapse was found between patients who underwent surgery before RT plus CCNU and those who received only RT plus CCNU (p = 0.74). CONCLUSION: Overall, the acute toxicity was moderate, and patient compliance was good. Reirradiation of high-grade glioma was associated with modest subjective and objective response rates. It is remarkable that median overall survival from relapse was 13.7 months.

Multiple fraction per day radiation therapy for inoperable esophageal cancer.

Experience with a multiple fractions per day radiation therapy program for inoperable esophageal cancer is reported. The treatment program consisted of 3 daily fractions of 1.6 Gy, with a 4 hr interval between fractions, for 5 consecutive days (24 Gy). After a rest period of 2 weeks, a second course of radiation was given with the same dose and fractionation for a total dose of 48 Gy in an overall treatment time of 4 weeks. Thirty-four patients were treated between February 1981 and July 1983. Acute reactions consisted of mild esophagitis noted in 30% of patients. No treatment related complications were reported. Median survival was 7 months and the 2- and 5-year survival rates were 12 and 9%, respectively. Tumor size and Karnofsky performance status were found to be the most important prognostic indicators for prolonged survival. Prompt palliation of symptoms was noted. Thirty-three per cent of patients had complete resolution and 41% had partial improvement of symptoms after completion of treatment. Four patients (12%) obtained complete tumor regression with negative biopsy at endoscopic examination and 2 of them are free of disease at 58 and 64 months. A partial response was reported in 12 patients (35%) for a median duration of 5 months (3-26). Treatment with multiple fractions per day was feasible in patients with esophageal cancer and could be preferred to more conventional fractionations for promptness of palliation and the shorter treatment time. The expected therapeutic gain is discussed.

Radiotherapy versus radiotherapy enhanced by cisplatin in stage III non-small cell lung cancer.

Between January 1987 and June 1991, 173 patients with inoperable non-small cell lung cancer, Stage III, were entered into a randomized trial comparing radiotherapy only (RT) (45 Gy/15 fractions/3 weeks) (arm A) versus RT and a daily low dose of cDDP (6 mg/m2) (arm B). An overall response rate of 58.9% was observed in arm A and 50.6% in arm B, respectively. No differences in the pattern of relapse were noted between the two treatment groups. Median time to progression was 10.6 months for arm A and 14.2 months for arm B. Median survivals were 10.3 months and 9.97 months, respectively. Toxicity was acceptable and no treatment-related death occurred in either treatment schedule. In this study no significant advantage of the combined treatment over radiation therapy only was found. The encouraging results achieved in some trials together with the intractability of the disease suggest that further efforts should be made to optimize clinical trial protocols, perhaps by reviewing the radiobiological and pharmacological basis of the combined treatment.