Time- and angle-resolved photoemission spectroscopy of solids in the extreme ultraviolet at 500 kHz repetition rate.

Time- and angle-resolved photoemission spectroscopy (trARPES) employing a 500 kHz extreme-ultraviolet light source operating at 21.7 eV probe photon energy is reported. Based on a high-power ytterbium laser, optical parametric chirped pulse amplification, and ultraviolet-driven high-harmonic generation, the light source produces an isolated high-harmonic with 110 meV bandwidth and a flux of more than 1011 photons/s on the sample. Combined with a state-of-the-art ARPES chamber, this table-top experiment allows high-repetition rate pump-probe experiments of electron dynamics in occupied and normally unoccupied (excited) states in the entire Brillouin zone and with a temporal system response function below 40 fs.

Understanding the origin of band gap formation in graphene on metals: graphene on Cu/Ir(111).

Understanding the nature of the interaction at the graphene/metal interfaces is the basis for graphene-based electron- and spin-transport devices. Here we investigate the hybridization between graphene- and metal-derived electronic states by studying the changes induced through intercalation of a pseudomorphic monolayer of Cu in between graphene and Ir(111), using scanning tunnelling microscopy and photoelectron spectroscopy in combination with density functional theory calculations. We observe the modifications in the band structure by the intercalation process and its concomitant changes in the charge distribution at the interface. Through a state-selective analysis of band hybridization, we are able to determine their contributions to the valence band of graphene giving rise to the gap opening. Our methodology reveals the mechanisms that are responsible for the modification of the electronic structure of graphene at the Dirac point, and permits to predict the electronic structure of other graphene-metal interfaces.

Radioterapia estereotáxica fraccionada en tumores cerebrales y de región cervical. Experiencia del Centro Médico Deán Funes (CMDF), primera experiencia en radioterapia estereotáxica y radiocirugía en el interior del país / Experience of fractionated stereotactic radiation therapy for tumors of the brain and head and neck

Objetivo: Se realizó un estudio retrospectivo para analizar los resultados de 53 pacientes (ptes.) sometidos a radioterapia estereotáxica fraccionada (REF) en el Centro Médico Deán Funes (CMDF). Los ptes. tratados con REF presentaban tumores encefálicos y de cabeza y cuello. Pacientes y métodos: Desde noviembre de 1997 hasta marzo de 2003, se trataron en el CMDF 53 ptes. con REF. Las dosis diarias variaron entre 1,8-2 Gy y las totales entre 30 y 70 Gy. El seguimiento mínimo fue de 2 meses y el medio de 32 meses. Se analizó el control local post-REF y la sobrevida en todos los ptes., así como la tolerancia y complicaciones del tratamiento. Resultados: Al tratarse de un grupo muy heterogéneo de ptes., los resultados finales fueron difíciles de comparar con otros tratamientos alternativos. Sin embargo, se observó una excelente tolerancia al mismo. Se observaron subgrupos de ptes. en los que obtuvieron buenos resultados...

Radioterapia estereotáxica fraccionada como tratamiento radiante en la metástasis orbital y ocular (reporte de tres casos) / Fraccionated stereotactic radiation therapy as treatment in retro-ocular and orbital metastasis: report of 3 cases

Tres pacientes, uno con metástasis ocular y dos con metástasis en órbita, fueron referidos para su tratamiento al CMPDF, Córdoba, Argentina. Todos ellos recibieron Radioterapia Estereotáxica Fraccionada (REF). En dos pacientes el tumor primario fue de mama y el restante de pulmón. La técnica de la REF es descripta en éste artículo, la dosis entregada fue de 50 Gy en 2 pacientes y de 58 Gy en 1 paciente. Este estudio analiza las características y los resultados obtenidos en éstos pacientes. Dos pacientes se hallan vivos y libres de enfermedad clínica en la órbita, al cierre del presente estudio; el paciente con metástasis ocular falleció por diseminación sistémica, con enfermedad ocular controlada. No se han observado complicaciones inmediatas o mediatas, referidas al tratamiento. Concluímos que la REF es una terapéutica muy efectiva para el tratamiento de lesiones metastásicas en órbita y sin evidencia de complicaciones severas

Carcinoma of the uterine cervix. II. Lack of impact of prolongation of overall treatment time on morbidity of radiation therapy.

PURPOSE: Several reports document a negative impact of prolongation of overall treatment time in a course of irradiation on tumor control and survival. A correlation has been documented of incidence of significant treatment sequelae with increasing doses of irradiation, volume of the specific organ, and dose per fraction. However, no data were found on the potential correlation of overall irradiation treatment time with significant sequelae. METHODS AND MATERIALS: Records were reviewed of 1,269 patients with carcinoma of the cervix (Stage IB to HI) treated with definitive irradiation (combination of external beam and two intracavitary insertions). Follow-up was obtained in 97% of patients (median, 12 years; minimum, 3 years; maximum, 28 years). The relationships between overall treatment time and time of brachytherapy and incidence of treatment sequelae were analyzed for each stage. RESULTS: Overall incidence of Grades 2 (moderate) sequelae was 7% and of Grade 3 (severe) sequelae, 11%. There was no significant correlation of various incidences of Grade 2 and 3 sequelae with overall treatment times (8% in patients treated in less than 7 weeks, 9% in 7.1 to 9 weeks, and 12% when treatment time was longer than 9 weeks) (p = 0.08). In patients with Stage IB and IIA tumors, incidence of rectal toxicity (mostly proctitis) was comparable in patients treated in less than 7 or 7.1 to 9 weeks (4.1 and 6%, respectively) and slightly higher in those treated in longer periods (11.5%) (p = 0.24). In patients with Stage IIB and III, the incidence of Grade 2 and 3 small bowel morbidity was 2% in those treated in less than 7 weeks, 6% for 7.1 to 9 weeks, and 4.9% for longer times (p < or = 0.01). This increased morbidity was also correlated with total dose of irradiation to the lateral pelvic wall: 5 of 257 (2%) for less than 60 Gy and 21 of 438 (4.8%) for higher doses (p < or = 0.01). There was no significant correlation between the timing of brachytherapy (usually two low dose rate intracavitary insertions performed within 4.5 to 6.5 weeks of initiation of external beam therapy) and significant treatment sequelae. CONCLUSIONS: We observed a varied average incidence of Grade 2 and 3 morbidity in the bladder, rectum, and small intestine with different overall treatment times, without a definite pattern to suggest an impact of prolongation of treatment time on morbidity. Likewise, there was no significant correlation with the timing of intracavitary insertions and morbidity of therapy. Because prolongation of the overall treatment time has a well-documented detrimental effect on pelvic tumor control and survival in carcinoma of the cervix with no significant impact on morbidity, it is imperative to deliver radiation therapy in the shortest possible time and without schedule interruptions.

Carcinoma of the uterine cervix. I. Impact of prolongation of overall treatment time and timing of brachytherapy on outcome of radiation therapy.

PURPOSE: Some studies have described decreased pelvic tumor control and survival rates in invasive carcinoma of uterine cervix when the overall time in a course of definitive irradiation is prolonged. We attempt to confirm or deny these observations and evaluate the impact of timing of brachytherapy on outcome. We also explore the hypothesis that more extensive tumors technically require prolongation of the course of irradiation; thus, decreased tumor control and survival in these patients may not necessarily be the result of time/dose factor. METHODS AND MATERIALS: Records of 1,224 patients (Stage IB to III) treated with definitive irradiation (combination of external beam and two intracavitary insertions to deliver doses of 70 to 90 Gy to point A) were reviewed. Follow-up was obtained in 97% of the patients (median, 12 years; minimum, 3 years; maximum, 28 years). The relationship between outcome and overall treatment time and time of intracavitary insertions was analyzed in each stage and according to tumor size/extent. RESULTS: There was strong correlation between overall treatment time (OTT) and tumor stage (< or = 7 weeks: 81% for Stage IB; 74% for Stage IIA; 52% for Stage IIB; and 47% for Stage III). Interruptions of therapy accounting for prolongation of treatment time occurred in 25-30% of patients, most frequently because of holidays and weekends and side effects of therapy. Overall treatment time had a major impact on pelvic tumor control in Stages IB, IIA, and IIB; in Stage IB 10-year actuarial pelvic failure rates were 7% with OTT < or = 7 weeks, 22% with 7.1 to 9 weeks, and 36% with > 9 weeks (p < or = 0.01). For Stage IIA the corresponding values were 14%, 27%, and 36% (p = 0.08), and in Stage IIB pelvic failure rates were 20%, 28%, and 34%, respectively (p = 0.09). In Stage III, pelvic failure was 30%, 40%, and 50%, respectively (p = 0.08). There was also a strong correlation between OTT and 10-year cause-specific survival (CSS); in Stage IB rates were 86% with OTT of < or = 7 weeks, 78% for 7.1 to 9 weeks, and 55% for > or = 9 weeks (p < 0.01). The corresponding rates in Stage IIA were 73%, 41%, and 48% (p < or = 0.01). For patients with Stage IIB, CSS rates were 72% for OTT < or = 7 weeks, 60% for 7.1 to 9 weeks, and 70% for > 9 weeks (p = 0.01). Patients with Stage III disease had 45% 10-year CSS when treatment was delivered in 9 weeks or less and 36% for longer overall times (p = 0.16). In multivariate analysis of patients with Stage IB and IIA, OTT and clinical stage were the most important prognostic factors for pelvic tumor control, disease-free survival, and CSS. Tumor size was a prognostic factor for CSS. In Stages IIB and III, OTT, clinical stage, unilateral or bilateral parametrial invasion, and dose to point A were significant prognostic factors for pelvic tumor control, disease-free survival, and CSS. Prolongation of time had a significant impact on pelvic tumor control and CSS regardless of tumor size, except in Stage IB tumors < or = 3 cm. Regression analysis confirms previous reports that prolongation of OTT results in decreased pelvic tumor control rate of 0.85% per day for all patients, 0.37% per day in Stages IB and IIA, 0.68% per day in Stage IIB, and 0.54% for Stage III patients treated with > or = 85 Gy to point A. Performance of all intracavitary insertions within 4.5 weeks from initiation of irradiation yielded decreased pelvic failure rates in some groups of patients (8.8 vs. 18% in Stage IB and IIA tumors < or = 4 cm and 12.3 vs. 35% in Stage IIB) (p < or = 0.01). CONCLUSIONS: Prolongation of treatment time in patients with Stage IB, IIA, IIB, and III carcinoma of the uterine cervix has a significant impact on pelvic tumor control and CSS. The effect of OTT was present regardless of tumor size except in Stage IB tumors < or = 3 cm.

Radiation treatment of early vocal cord carcinoma. Eighteen years experience at "Instituto de Oncologia y Radioterapia de Mar del Plata".

A detailed retrospective analysis of 260 patients with T 1 NO MO vocal cord carcinoma treated at "Instituto de Oncologia y Radioterapia de Mar del Plata" from 1967 to 1985 was performed. The majority of the patients were in the age range of 50 to 79 years, and 79% were males. The overall observed three year tumor free survival was 85.3%. When survival rate was adjusted for intercurrent disease and second primary tumor death, the 3 year tumor free survival was 92%. Sixty two percent of the patients (17/27) undergoing surgical salvage for recurrence, were controlled. Second primary tumors were seen in 18 patients (6.9%). It is emphasized the importance of close follow up to diagnose as early as possible both the vocal cord recurrence and the second primary tumors.

Improved survival in cases of intracranial ependymoma after radiation therapy. Late report and recommendations.

A publication from the University of Rochester Cancer Center in 1975 suggested an improvement in the survival time of patients with intracranial ependymomas in whom an aggressive postoperative radiation therapy approach had been adopted. The regimen was tailored to the aggressiveness and spread patterns of these tumors and therefore considered the patient's age, tumor histopathology and location, and status of the subarachnoid space and cerebrospinal fluid (CSF). The authors proposed using whole brain (WB) fields for all patients with low-grade supratentorial tumors, and WB with cervical cord field extensions for low-grade infratentorial tumors if either group had no CSF or subarachnoid evidence of spinal metastases. They also proposed using craniospinal irradiation for all patients with high-grade ependymomas (regardless of location) or with low-grade infratentorial tumors with positive CSF or subarachnoid findings of spinal metastases. Recommended doses were as follows: 4500 rads to the whole brain, 5500 rads to the primary tumor volume, and 3000 to 4000 rads to the spine, depending on its subarachnoid status. Children aged 3 years or under were to receive 80% of these doses and more protracted daily treatments. Analysis of the updated experience indicates that in 51 patients treated with this approach these criteria have yielded a beneficial and consistent increase in the survival time. A 69% 10-year survival rate has been observed (75% for low-grade and 67% for high-grade ependymomas). A multifactorial analysis of survival by prognostic factors and by grouping of prognostic factors, analysis of failures, autopsy findings, and quality of survival is presented and discussed.

Nasopharyngeal carcinoma in the second decade of life.

The clinical findings and treatment results in 27 patients, 11 to 20 years of age, with nasopharyngeal carcinoma were retrospectively reviewed. The histological diagnosis was lymphoepithelioma in 18 patients and undifferentiated carcinoma in nine patients. Seven patients (26%) presented with T4 lesions, 24 patients (89%) with clinically positive cervical nodes, and two patients (7%) with distant metastases. All patients received radiation therapy to the primary site; chemotherapy was employed as an adjuvant in six patients. Overall survival was 64% at five years and 57% at 10 years. Local control of the primary tumor and regional lymph nodes was 85%. Distant metastases were more frequent in patients with advanced primary disease and were associated wtih extremely poor prognoses. A moderate dose of radiotherapy is the recommended treatment for primary tumors and neck nodes. More effective adjuvant chemotherapy is suggested as a possible way to improve therapeutic results.

Medulloblastomas.

"Analysis of 29 cases evaluated at SMG, Rochester, N.Y." This study analyzed 29 patients with the diagnosis of medulloblastoma evaluated at Strong Memorial Hospital, Rochester, New York. Twenty-three patients received combined (surgery and radiotherapy) treatment. Six had surgery alone. Chemotherapy was never employed as a primary treatment, however, two cases were treated with drugs at the time of relapse. The patients having craniospinal irradiation had a better survival rate when compared with the group receiving cranial irradiation or surgery alone. The five year survival rate for the first group was 50% versus 20% for the second group and 0% for the third group. The main cause of failure was recurrence in the posterior fossa. Fifteen patients failed in this area representing 88% of the total failures. Seeding to the spinal cord was determined in 5 patients, four of whom did not have spinal cord irradiation. One patient failed outside the field of treatment in the conus medullaris six months after radiation.