[Rotator cuff tear--an occupational disease? An epidemiological analysis]. / Rotatorenmanschettendefekt--eine Berufserkrankung?

BACKGROUND: In literature there are only few data which describe the influence of occupation on the development of rotator cuff disease. METHODS: In a retrospective study, 760 open rotator cuff repairs were analysed and related to the profession and occupational load. Exclusion criteria were traumatic tears and sports injuries. All male persons were statistically analysed and the data compared with occupational patterns of the region, obtained from the Federal Statistical State Office. RESULTS: Rotator cuff repairs were performed in 472 males who had no evidence for a traumatic origin. After statistical analysis (p < 0.001) we found significantly more patients working in agriculture and forestry (6.38% versus 1.07% in Bavaria) and in the building industry (35.11% versus 13.40% in Bavaria). CONCLUSIONS: Our data suggest that working exposure increases the risk or leads to the clinical manifestation of rotator cuff tears. Although a detailed analysis of individual physical exposure is not available yet, the statistical results indicate that rotator cuff tears must be taken into consideration as a result of ergonomic exposure.

The effect of ambient pressure on well chamber response: experimental results with empirical correction factors.

For some air-communicating well-type chambers used for low-energy brachytherapy source assay, deviations from expected values of measured air kerma strength were observed at low pressures associated with high altitudes. This effect is consistent with an overcompensation by the air density correction to standard atmospheric temperature and pressure (P(TP)). This work demonstrates that the P(TP) correction does not fully compensate for the high altitude pressure effects that are seen with air-communicating chambers at low photon energies in the range of 20-100 keV. Deviations of up to 18% at a pressure corresponding to an approximate elevation of 8500 ft for photon energies of 20 keV are possible. For high-energy photons and for high-energy beta emitters in air-communicating chambers the P(TP) factor is applicable. As expected, the ambient pressure does not significantly affect the response of pressurized well chambers (within 1%) to either low- or high-energy photons. However, when used with beta emitters, pressurized chambers appear to exhibit a slight dependence on the ambient pressure. Using measured data, the response and correction factors were determined for three models of air-communicating well chambers for low-energy photon sources at various pressures corresponding to elevations above sea level. Monte Carlo calculations were also performed which were correlated with the experimental findings. A more complete study of the Monte Carlo calculations is presented in the accompanying paper, "The effect of ambient pressure on well chamber response: Monte Carlo calculated results for the HDR1000 Plus."

The German Short Musculoskeletal Function Assessment questionnaire: reliability, validity, responsiveness, and comparison with the Short Form 36 and Constant score--a prospective evaluation of patients undergoing repair for rotator cuff tear.

In a prospective clinical trial, first the German Short Musculoskeletal Function Assessment questionnaire (SMFA-D) was tested for reliability, validity, and responsiveness in 23 patients with rotator cuff tears, and secondly the Short Form (SF)-36, and the Constant score were evaluated comparatively in 45 patients with rotator cuff tear undergoing open repair. Retest reliability was excellent for the functional index of the SMFA-D and satisfactory for the bother index. The SMFA-D showed good validity and responsiveness. All three instruments demonstrated significantly the positive effect of rotator cuff repair at 12-month follow-up. Using comparable scales, effect sizes were bigger with the SMFA-D than with the SF-36 and as big as the Constant score. Significant correlations of the SMFA-D indices with the SF-36 scales and the Constant score could be shown preoperatively. At 12-month follow-up, all correlations between SMFA-D indices, SF-36 scales, and Constant score function scales were still significant. We recommend use of the SMFA-D to assess changes in functional status concerning patients with rotator cuff tear undergoing open repair.

Dose rate table for a 32P intravascular brachytherapy source from Monte Carlo calculations.

Studies of intravascular brachytherapy to prevent restenosis following angioplasty have shown many promising results. Accurate dose rate tables based on detailed models of the brachytherapy sources are necessary for treatment planning. This work will present an away and along dose rate table for a 27 mm long catheter based 32P beta source. MD-55-2 radiochromic film has been exposed at five different depths (0.5 mm-4 mm) in a polystyrene phantom using a 27 mm long Guidant 32P beta source. The total dose to the active region of the film was determined using the absolute detector response of the MD-55-2 radiochromic film. The Monte Carlo code MCNP4B2 was also used to calculate the dose to the active region of the film using a detailed model of the source, encapsulation, and radiochromic film. The dose to film calculations showed good agreement with the measurements presented in this work with an average difference of 7%. The Monte Carlo calculations were also verified against previously published depth dose in water measurements determined using radiochromic film and plastic scintillator. The depth dose calculations in water showed good agreement with the previously published measurements with the calculations being about 2.5% lower than the film measurements and about 2.5% higher than the scintillator measurements. This work then uses the verified Monte Carlo code to present a dose rate table for the 32P intravascular beta source.

Measurements and Monte Carlo calculations to determine the absolute detector response of radiochromic film for brachytherapy dosimetry.

GafChromic (MD-55-2) radiochromic film has become increasingly popular for medical applications and has proven to be useful for brachytherapy dosimetry. To measure the absolute dose near a brachytherapy source, the response of the proposed detector in the measurement conditions relative to the response of the detector in calibration conditions must be known. MD-55-2 radiochromic film has been exposed in four different photon beams, a 30 and 40 kVp tungsten anode x-ray beam, a 75 kVp orthovoltage therapy beam, and a 60Co teletherapy beam to measure the relative detector response. These measurements were combined with coupled photon/electron Monte Carlo transport calculations to determine the absolute detector response. The Los Alamos National Laboratory Monte Carlo transport code MCNP4B2 was used. The measured relative response of this batch of MD-55-2 film varies from 8.79 mOD/Gy, measured for the 60Co beam, by as much as 42% for the low-energy x-ray beams. However, the absolute detector response varies from 4.32 mOD/Gy for the 60Co beam by, at most, only 6.3%. In this work we demonstrate that the absolute detector response of MD-55-2 radiochromic film is a constant and independent of beam quality. Further, this work shows that MCNP4B2 accurately simulates the energy response and geometry artifacts of the radiochromic film.

Monte Carlo calculations to characterize the source for neutron therapy facilities.

Modern radiation treatment planning for photons includes full 3D modeling of the adsorbed dose distribution, accurate inclusion of the patient anatomy, and consideration of significant changes in material density and composition. Such efforts are founded in an accurate description of the radiation source and the beam delivery system. Modern fast neutron therapy facilities employ highly penetrating beams and isocentric beam delivery. Treatment planning is largely based on analytic models adapted from photon codes and interaction cross sections normalized to macroscopic attenuation. However, the recent PEREGRINE initiative at Lawrence Livermore Laboratory offers the possibility of fully stochastic modeling if the neutron source can be adequately described. In this article we report neutron source modeling of three high energy facilities. Neutron production is based on the intra-nuclear cascade model of the LAHET code while neutron transport through the beam delivery system is managed by MCNP using cross section libraries extended to 100 MeV neutron energy. PEREGRINE is then used to transport the neutron beam through typical phantoms. The resulting neutron sources are in excellent agreement with the limited experimental information and the measured phantom data are well described by the PEREGRINE transport using the LAHET/MCNP determined neutron sources.