Patient and physician perceptions of lung cancer care in a multidisciplinary clinic model.

Background: Lung cancer (lc) is a complex disease requiring coordination of multiple health care professionals. A recently implemented lc multidisciplinary clinic (mdc) at Kingston Health Sciences Centre, an academic tertiary care hospital, improved timeliness of oncology assessment and treatment. This study describes patient, caregiver, and physician experiences in the mdc. Methods: We qualitatively studied patient, caregiver, and physician experiences in a traditional siloed care model and in the mdc model. We used purposive sampling to conduct semi-structured interviews with patients and caregivers who received care in one of the models and with physicians who worked in both models. Thematic design by open coding in the ATLAS.ti software application (ATLAS.ti Scientific Software Development, Berlin, Germany) was used to analyze the data. Results: Participation by 6 of 72 identified patients from the traditional model and 6 of 40 identified patients from the mdc model was obtained. Of 9 physicians who provided care in both models, 8 were interviewed (2 respirologists, 2 medical oncologists, 4 radiation oncologists). Four themes emerged: communication and collaboration, efficiency, quality of care, and effect on patient outcomes. Patients in both models had positive impressions of their care. Patients in the mdc frequently reported convenience and a positive effect of family presence at appointments. Physicians reported that the mdc improved communication and collegiality, clinic efficiency, patient outcomes and satisfaction, and consistency of information provided to patients. Physicians identified lack of clinic space as an area for mdc improvement. Conclusions: This qualitative study found that a lc mdc facilitated patient communication and physician collaboration, improved quality of care, and had a perceived positive effect on patient outcomes.

Time-resolved xenon flash-lamp opacity measurements.

A laser-aided technique has been used for measuring time-resolved optical transmissions of xenon flash lamps at numerous visible and infrared wavelengths, flash-lamp current densities, lamp diameters, pulse durations, and xenon pressures. Long-pulse (˜ 600-µs) and short-pulse (˜ 10-µs) cases specific for optically pumping solid-state, dye, and atomic iodine lasers were studied. Opacity measurements were made for flash-lamp current densities up to 30 kA/cm(2) . Flash lamps having fused silica envelope diameters between 0.8 and 4.5 cm and xenon pressures between 2 and 450 Torr were investigated in these experiments. Xenon temperatures between 6000 and 25,000 K were estimated from the frequencies of observed arc-acoustic oscillations. Important applications for increasing the pumping efficiencies of large Nd:glass and photolytic iodine laser amplifiers are discussed.

Experimental studies of a zeeman-tuned xenon laser differential absorption apparatus.

A Zeeman-tuned cw xenon laser differential absorption device is described. The xenon laser was tuned by axial magnetic fields up to 5500 G generated by an unusually large water-cooled dc solenoid. Xenon laser lines at 3.37 micro, 3.51 micro, and 3.99 micro were tuned over ranges of 6 A, 6 A, and 11 A, respectively. To date, this apparatus has been used principally to study the details of formaldehyde absorption lines lying near the 3 .508-micro xenon laser transition. These experiments revealed that the observed absorption spectrum of formaldehyde exhibits a sufficiently unique spectral structure that the present technique may readily be used to measure relative concentrations of formaldehyde in samples of polluted air.

Nd:YAG Long Lasers.

The oscillation characteristics and dynamics of Nd:YAG long lasers are described. Nd:YAG laser cavities ranging in length from 1 m to over 6.3 km were constructed and operated. The development of laser oscillation, power output, active angular fields, and resonances of the circulating optical flux were monitored. Although Nd:YAG is a homogeneously broadened laser amplifier, the Nd:YAG long laser exhibited characteristics of inhomogeneously broadened lasers of conventional lengths. A dynamical resonance was observed and identified as a resonance between the laser amplifier pumping rate and the stimulated emission rate.

Laser-beam apodization with a graded random phase window.

Experiments and analysis indicate that graded random phase modulation can be used to apodize a laser beam. In the case of an obscuration or a hard edge it can prevent the formation of Fresnel-diffraction ripples. For example, here the interaction of a 1-microm-wavelength laser beam with a central obscuration of half-width a = 100 microm is studied theoretically. It is found that if the exit surface of a window, placed immediately downstream of the obstacle, is randomly modulated with a Gaussian amplitude transverse correlation length l = 50 microm and a mean-square amplitude that decreases exponentially from a peak height of ~1 microm(2) away from the center of the obscuration with transverse scale length L = 500 microm, then the Fresnel-diffraction ripples normally produced by the obscuration are eliminated. The scaling of these results is also discussed. The calculations are in general agreement with experimental results.

Closure phenomena in pinholes irradiated by Nd laser pulses.

An experimental investigation has been made on plasma closure in pinholes irradiated by Nd glass laser pulses; 300micro500-microm diam pinholes of various materials and thicknesses have been irradiated by 20-100-J 300-psec FWHM pulses on the Janus laser system. Calorimetry measurements have yielded data on pinhole energy transmission and intensity loading on the periphery of the pinhole. Ultrafast streak photography measurements indicate effective closure velocities of 2-5 x 10(7) cm/sec. Scattered light measurements have shown the transmission loss through a typical spatial filter configuration to be primarily refractive in nature.

Very long lasers.

The properties and oscillation characteristics of very long cw xenon lasers are discussed and pertinent long laser experiments described. High-gain 3.508-microm xenon laser amplifiers were used in these experiments. Laser cavity lengths of up to 30 km were studied. Spectrum analyses revealed complex oscillation spectra exhibiting the characteristics of both homogeneous and inhomogeneous laser mode structures. Long laser Doppler experiments, Q-switching studies, and modulation experiments were performed. Applications to atmospheric pollution detection are discussed.

Pump-induced optical distortions in disk amplifier modules: holographic and interferometric measurements.

Interferometric measurements have been made of the optical distortions induced in laser disk amplifiers during the flashlamp pumping pulse. Both conventional interferometric methods and the techniques of double exposure holographic interferometry were used to identify four major sources of pump-induced optical distortions: subsonic intrusion of hot gas (traced to leakage of atmospheric oxygen into the amplifier), microexplosions of dust particles, thermally induced optical distortions in the glass disks, and gaseous optical distortion effects caused by turbulent flow of the purging nitrogen gas supply used within the laser amplifier head. Methods for reducing or eliminating the effects of each of these optical distortions are described.

Large aperture harmonic conversion experiments at Lawrence Livermore National Laboratory.

Large aperture harmonic conversion experiments to 2 omega (532 nm), 3 omega (355 nm), and 4 omega (266 nm) on the Argus laser at the Lawrence Livermore National Laboratory are described. Harmonically converted energies of up to 346 J have been generated at external conversion efficiencies of 83%. A discussion of the harmonic conversion experiments and a brief summary of enhanced 2 omega and 3 omega inertial confinement fusion target performances are provided.