Purpose: The presented study aimed at optimizing a patient table design for breast CT (BCT) systems with respect to breast tissue coverage and patient comfort. Additionally, the benefits and acceptance of an immobilization device for BCT using underpressure were evaluated. Materials and Methods: Three different study parts were carried out. In a positioning study women were investigated on an MRI tabletop with exchangeable inserts (flat and cone-shaped with different opening diameters) to evaluate their influence on breast coverage and patient comfort in various positioning alternatives. Breast length and volume were calculated to compare positioning modalities including various opening diameters and forms. In the second study part, an underpressure system was tested for its functionality and comfort on a stereotactic biopsy table mimicking a future CT scanner table. In the last study part, this system was tested regarding breast tissue coverage. Results: Best results for breast tissue coverage were shown for cone-shaped table inserts with an opening of 180?mm. Flat inserts did not provide complete coverage of breast tissue. The underpressure system showed robust function and tended to pull more breast tissue into the field of view. Patient comfort was rated good for all table inserts, with highest ratings for cone-shaped inserts. Conclusion: Cone-shaped tabletops appeared to be adequate for BCT systems and to allow imaging of almost the complete breast. An underpressure system proved promising for the fixation of the breast during imaging and increased coverage. Patient comfort appears to be adequate. Key points:

Purpose: The presented study aimed at optimizing a patient table design for breast CT (BCT) systems with respect to breast tissue coverage and patient comfort. Additionally, the benefits and acceptance of an immobilization device for BCT using underpressure were evaluated. Materials and Methods: Three different study parts were carried out. In a positioning study women were investigated on an MRI tabletop with exchangeable inserts (flat and cone-shaped with different opening diameters) to evaluate their influence on breast coverage and patient comfort in various positioning alternatives. Breast length and volume were calculated to compare positioning modalities including various opening diameters and forms. In the second study part, an underpressure system was tested for its functionality and comfort on a stereotactic biopsy table mimicking a future CT scanner table. In the last study part, this system was tested regarding breast tissue coverage. Results: Best results for breast tissue coverage were shown for cone-shaped table inserts with an opening of 180 mm. Flat inserts did not provide complete coverage of breast tissue. The underpressure system showed robust function and tended to pull more breast tissue into the field of view. Patient comfort was rated good for all table inserts, with highest ratings for cone-shaped inserts. Conclusion: Cone-shaped tabletops appeared to be adequate for BCT systems and to allow imaging of almost the complete breast. An underpressure system proved promising for the fixation of the breast during imaging and increased coverage. Patient comfort appears to be adequate.

The findings of this study encourage the combined usage of TDS and FSC in systems that require fast rotation. The integration of TDS in state-of-the-art x-ray detectors is feasible.

Abstract. Various applications require information on breast parameters, such as breast length and volume. An optical system was designed and tested for measuring these parameters with subjects in a prone position. The study results were used for optimizing patient positioning and handling for a future breast computed tomography (BCT) system. Measurements were conducted using an optical measurement system. To test the functionality and accuracy of the system, measurements were performed using reference phantoms. Additionally, 20 women and 5 men were examined to calculate breast parameters in alternative positions and breathing states. The results of the optical measurements were compared with magnetic resonance imaging (MRI) measurements. Volume and length of the reference phantoms were determined with errors below 2%. The patient study demonstrated a mean breast volume of 530.7 ml for women during normal breathing. During an exhalation state, breast volume increased significantly by 17.7 ml in comparison with normal breathing. Differences with MRI measurements were found to be 3% for breast length and 9% for breast volume on average. The proposed optical measurement system was found to be suitable for measuring the dimensional parameters of the breast in a prone position and provides a tool for evaluating breast coverage for BCT.

A requirement to be met when administering perioperative prophylactic antibiotics as a standard with many orthopedic surgeons in artificial joint replacement is the achievement of sufficient concentrations of substance in the operative field. Following the i.v. short-infusion of 1.5 mg Cefuroxime-Sodium in 65 cases of knee joint surgery using a mid-thigh tourniquet substance levels were measured in samples of blood serum, synovial fluid and knee joint capsule. The Cefuroxime concentration in synovial fluids was found to be an average of 25.3 +/- 15.4 mcg/ml at the beginning and 14.9 +/- 10.7 mcg/ml at the end of the operations. Samples of joint capsule that had been taken during the operation showed substance levels of 20.6 +/- 11.1 mcg/ml. 13% of these samples showed substance levels below 4.0 mcg/ml which is the estimated breakpoint of full sensitivity of potentially infective bacteria. The relation of Cefuroxime concentrations in the synovial fluid to the length of time between the end of the infusion and the application of the tourniquet proved to be statistically nonsignificant (covariance analysis; p = 0.05). Nevertheless the determined differences showed a tendency which agrees with the findings of other authors who conclude, that a minimum exposure time of ten minutes is essential.