Real-time automatic temperature regulation during in vivo MRI-guided laser-induced thermotherapy (MR-LITT).

Precise control of tissue temperature during Laser-Induced Thermotherapy (LITT) procedures has the potential to improve the clinical efficiency and safety of such minimally invasive therapies. We present a method to automatically regulate in vivo the temperature increase during LITT using real-time rapid volumetric Magnetic Resonance thermometry (8 slices acquired every second, with an in-plane resolution of 1.4 mmx1.4 mm and a slice thickness of 3 mm) using the proton-resonance frequency (PRF) shift technique. The laser output power is adjusted every second using a feedback control algorithm (proportional-integral-derivative controller) to force maximal tissue temperature in the targeted region to follow a predefined temperature-time profile. The root-mean-square of the difference between the target temperature and the measured temperature ranged between 0.5 °C and 1.4 °C, for temperature increases between + 5 °C to + 30 °C above body temperature and a long heating duration (up to 15 min), showing excellent accuracy and stability of the method. These results were obtained on a 1.5 T clinical MRI scanner, showing a potential immediate clinical application of such a temperature controller during MR-guided LITT.

30 TW and 33 fs pulses delivered by a Ti:Sa amplifier system seeded with a frequency-doubled fiber laser.

We report a full experimental comparison study on the injection of a Ti:Sa multi-terawatt amplifier chain with a standard 15 fs Ti:Sa oscillator and 35 fs frequency-doubled fiber oscillator. The study highlights that the Ti:Sa oscillator, with high performance in terms of pulse duration and spectral width, can be replaced by the frequency-doubled fiber oscillator to seed Ti:Sa amplifier chains almost without any compromise on the output pulse duration and picosecond contrast. Finally, we demonstrate for the first time to our knowledge a 30 TW and 33 fs Ti:Sa amplifier injected by a fiber oscillator.

Ultra-low intensity noise, all fiber 365 W linearly polarized single frequency laser at 1064†nm.

We demonstrate a robust linearly polarized 365 W, very low amplitude noise, single frequency master oscillator power amplifier at 1064 nm. Power scaling was done through a custom large mode area fiber with a mode field diameter of 30 µm. No evidence of stimulated Brillouin scattering or modal instabilities are observed. The relative intensity noise is reduced down to -160 dBc/Hz between 2 kHz and 10 kHz via a wide band servo loop (1 MHz bandwidth). We achieve 350 W of isolated power, with a power stability < 0.7% RMS over 1100 hours of continuous operation and a near diffraction limited beam (M2 < 1.1).

Langerhans cell histiocytosis or tuberculosis on a medieval child (Oppidum de la Granède, Millau, France - 10th-11th centuries AD).

In 2008, a skeleton of a 1 - 2.5-year-old child radiocarbon dated from the 10th - 11th century AD was discovered on the oppidum of La Granède (Millau, France). It presents multiple cranial osteolytic lesions having punched-out or geographical map-like aspects associated with sequestrum and costal osteitis. A multi 3D digital approach (CT, µCT and virtual reconstruction) enabled us to refine the description and identify the diploic origin of the lytic process. Furthermore, precise observation of the extent of the lesions and associated reorganization of the skeletal micro-structure were possible. From these convergent pieces of evidence, the differential diagnosis led to three possibilities: Langerhans cell histiocytosis, tuberculosis, or Langerhans cell histiocytosis and tuberculosis.

A 2-hour information session and patient recall has minimal impact on glaucoma-treatment persistence in a mature practice.

PURPOSE: To study the impact of a 2-hour information session and 3 patients' phone calls on patient persistence with glaucoma medication. PATIENTS AND METHODS: All patients with glaucoma treatment, part of a 27-year old solo glaucoma practice, were invited to attend the information session. Patients who attended the session (n=342) were contacted by phone 1, 4, 10 months later and regular use of drops was stressed. Patients were unaware of the study. We compared the persistence of the patients before and after attending the session, and their persistence to that of patients who did not attend (n=1187). Persistence with glaucoma medication was assessed by examination of data (2002 to 2007) from a provincial medical and drug insurance database. RESULTS: Patients attending the session had glaucoma for 10 years. They had a better persistence than those who did not attend (P<0.05). Their persistence remained the same 1 year after attending the session but tended to be improved in the first 180 days (P<0.076). During the study period, there was a 4% increase in overall persistence (P<0.05). This could be due to an increase in prostaglandins prescriptions and changes in ß-blockers formulation. CONCLUSIONS: The information session and patient's recalls had a limited impact on patient persistence. This could be due to the selection of a population already persistent (78.9%). The results could have been different in less persistent patients and new patients. It could be different in another practice setting.

Follow-up of angle closure glaucoma suspects after laser iridotomy in Caucasians with normal intraocular pressure at diagnosis.

OBJECTIVE: To study the long-term outcome of Caucasian eyes with iridotrabecular trabecular apposition or peripheral anterior synechiae (PAS) and fellow eyes with narrow angles only, in eyes with intraocular pressure (IOP) <22 mm Hg at diagnosis and treated with laser peripheral iridotomy (LPI). DESIGN: Cohort study. PARTICIPANTS: Two hundred and fifty-seven Caucasian phakic patients (469 eyes) with a minimum follow-up of 2 years that had both an undilated and dilated gonioscopy after LPI. METHODS: In this retrospective cohort study, we included phakic patients with a minimum follow-up of 2 years that had both an undilated and dilated gonioscopy after LPI. Excluded were patients with pseudoexfoliation, intraocular surgery, prior acute angle-closure glaucoma or antiglaucoma medication, suspicious glaucoma disk, secondary angle closure, or iridoplasty. We censored patients after any kind of intraocular surgery. Main outcome measures where the date of IOP elevation and beginning of antiglaucoma medication. RESULTS: Four hundred and sixty-nine eyes were included. Mean follow-up was 8.5 ± 5.53 years. No apposition/PAS was observed in 84.0% of the eyes after LPI. At 10 years, 38.7% of the eyes had increased IOP and 17.3% required medication. No difference in outcomes was observed between argon and neodymium-YAG LPI or between the eyes with and without apposition/PAS before LPI. Younger patients and those with no apposition/PAS after LPI had a better prognosis (p < 0.01). CONCLUSIONS: Many angle closure glaucoma suspects developed increased IOP and required medical treatment after LPI.