Impact of intelligent virtual and AI-based automated collimation functionalities on the efficiency of radiographic acquisitions.

INTRODUCTION: Intelligent virtual and AI-based collimation functionalities have the potential to enable an efficient workflow for radiographers, but the specific impact on clinical routines is still unknown. This study analyzes primarily the influence of intelligent collimation functionalities on the examination time and the number of needed interactions with the radiography system. METHODS: An observational study was conducted on the use of three camera-based intelligent features at five clinical sites in Europe and the USA: AI-based auto thorax collimation (ATC), smart virtual ortho (SVO) collimation for stitched long-leg and full-spine examinations, and virtual collimation (VC) at the radiography system workstation. Two people conducted semi-structured observations during routine examinations to collect data with the functionalities either activated or deactivated. RESULTS: Median exam duration was 31 vs. 45 s (p < 0.0001) for 95 thorax examinations with ATC and 94 without ATC. For stitched orthopedic examinations, 34 were performed with SVO and 40 without SVO, and the median exam duration was 62 vs. 82 s (p < 0.0001). The median time for setting the ortho range - i.e., the time between setting the upper and the lower limits of the collimation field - was 7 vs. 16 s for 39 examinations with SVO and 43 without SVO (p < 0.0001). In 109 thorax examinations with ATC and 112 without ATC, the median number of system interactions was 1 vs. 2 (p < 0.0001). VC was used to collimate in 2.4% and to check the collimation field in 68.5% of 292 observed chest and other examinations. CONCLUSION: ATC and SVO enable the radiographer to save time during chest or stitched examinations. Additionally, ATC reduces machine interactions during chest examinations. IMPLICATIONS FOR PRACTICE: System and artificial intelligence can support the radiographer during the image acquisition by providing a more efficient workflow.

[Cost effectiveness of intraoperative three-dimensional imaging with a mobile surgical C-arm]. / Wirtschaftlichkeit der intra- operativen 3D-Bildgebung mit einem mobilen chirurgischen C-Bogen.

DRGs lead to a new definition of refunding medical treatment. The calculated DRG covers all costs of the individual hospital stay of each patient. Any revision surgery is not refunded separately. Especially in spine surgery and in articular fractures, postoperative X-ray control sometime reveals malposition of implants that later require operative revision. The latter causes additional costs that can be in the range of 50% of the whole refund as shown here for tibia plateau and calcaneus fractures. New intraoperative 3D fluoro techniques provide CT-like images of bones and joints that enable the surgeon to optimize implant positions immediately. Despite higher initial costs as compared to conventional imaging devices, these technologies help to increase process quality in the OR and clearly save costs.

Intraoperative 3D imaging of the facial skeleton using the SIREMOBIL Iso-C3D.

OBJECTIVES: With respect to high-contrast structures, cone beam computed tomography (CBCT) offers an alternative imaging modality to computed tomography (CT), requiring less radiation exposure. The C-arm system SIREMOBIL Iso-C3D for three-dimensional (3D) reconstruction has made this modality available for intraoperative use. This paper presents the first intraoperative images of the facial skeleton using the SIREMOBIL Iso-C3D. METHODS: Cases of a zygomaticomaxillary complex fracture, a mandibular angle fracture and a bimaxillary repositioning osteotomy are described to demonstrate the application possibilities of this system in maxillofacial surgery. RESULTS: In addition to the uncomplicated handling of the SIREMOBIL Iso-C3D, generally important was the low level of metal artefacts in its primary and secondary reconstructions, even in close proximity to the material. However, it has to be kept in mind that while soft tissues are visualized using CBCT, information about soft tissue quality cannot be obtained. CONCLUSION: The SIREMOBIL Iso-C3D generates intraoperative data sets suitable for the visualization of the facial bones after open reduction of fractures.

[Radiation dosage in orthopedics -- a comparison of computer-assisted procedures]. / Strahlendosis im OP--ein Vergleich computerassistierter Verfahren.

Since the 1990s, computer-assisted methods have been well-established in the field of orthopedics and traumatology. In addition to the proven improvement in the field of surgical precisioncompared with conventional techniques, the decrease in the amount of emitted ionizing radiation inside of the operating room was cited to constitute an additional major advantage of computer-based navigation. The goal of this study was to quantify X-ray dose values exposed during both conventional methods and computer-assisted procedures, the latter being performed using a C-arm device SIREMOBIL Iso-C3D (Siemens Medical Solutions). The clinical measurements were supplemented by laboratory experiments using a pinpoint ionization chamber placed inside a standard lucite phantom. The clinical part of the study investigated the application of new, i.e. computer assisted, techniques in comparison with conventional procedures on in total 42 patients experiencing surgery either on their lower extremities (n = 14) or on the spine (n = 28). The techniques applied were: (1) conventional surgical procedure, (2) CT-based navigation, (3) C-arm navigation, and (4) Iso-C3D-navigation. The main focus of the clinical evaluation was the determination of radiation dose values by means of thermoluminescence dose meters, accompanied by the registration of the operation times of the X-ray tube during a surgical intervention. The conclusions from the clinical studies are in agreement with the results from the laboratory measurements. Computer-assisted techniques led to a significant reduction in X-ray dose exposure and drastically shortened irradiation times. The most pronounced decrease in the emission of ionizing radiation was achieved in case of the Iso-C3D-navigation, which has only recently been introduced into clinical practice, i.e. during runtime of this study.

[Computer assisted surgery, 2001 development and prospects. Results of a congress at Reisensburg Castle, 23-24 November 2000]]. / Computer assistierte Chirurgie, Entwicklung und Perspektiven 2001. Ergebnisse einer Arbeitstagung auf Schloss Reisensburg, 23./24.11.2000.

The progress in computer assisted surgery (CAS) is influenced by new technologies in imaging as well as by the input of the users. At present, CAS procedures are established in dorsal spine instrumentation, prosthetics and long bone surgery. Present status and future of CAS was a topic of an expert meeting at the Reisensburg castle. Imaging will speed up in the future using multi-detector techniques. C-arm navigation will gain more information using the 3D technology intraoperatively. CT based navigation procedures are standard in spine and will be established in pelvic surgery. CAS in robotics at the moment means the use of robot-assistance. A new concept is the modality-based navigated surgery, which can be used at various skeletal locations. Visualization of patient data will improve using 3D semi-transparencies with real time update. In the future it will be mandatory to find algorithms to fuse the different possibilities and techniques. A new concept of surgical training is necessary to teach CAS procedures. Therefore discussion must go on to improve these systems.

[Comparative study of the quality of C-arm based 3D imaging of the talus]. / Vergleichende Untersuchung zur Qualität der C-Bogenbasierten 3D-Bildgebung am Talus.

Malposition of extraosseous or intra-articular screws, e.g., in osteosyntheses of joint fractures or in the vicinity of joints, frequently remains undiscovered in intraoperative fluoroscopy and is only recognized on postoperative computed tomography (CT) scans. The aim of the study, therefore, was to assess the value of a new mobile C-arm three-dimensional imaging device in comparison with fluoroscopy, conventional radiographs, and CT scans using an extremity model. Screws were inserted ventrally in four anatomic lower leg specimens without talus fractures parallel to the longitudinal axis to simulate surgical management of fractures of the talus. The specimens supplied were examined with fluorscopy, conventional radiography, spiral CT, and the new three-dimensional imaging with the SIREMOBIL Iso-C3D. These four modalities were evaluated by ten radiologists and ten trauma surgeons and were compared regarding subjective image quality and position of the screws. The quality of information acquired with the SIREMOBIL Iso-C3D was equal to that of the CT examinations, although image quality was considered inferior to fluoroscopy, conventional radiography, and CT (p < 0.001). In contrast to the previous procedure with intraoperative fluoroscopy and subsequent postoperative X-ray control, the results obtained with the SIREMOBIL IsoC3D were superior. The SIREMOBIL Iso-C3D is useful for the intraoperative diagnosis of small joints with few artifacts producing osteosynthesis material, i.e., for recognizing the position of screws in the region of glenoid surfaces.

[Computer-assisted surgery: developments and prospects in 2001. Results of a workshop at Schloss Reisenburg, 23-24 November 2000]. / Computer assistierte Chirurgie, Entwicklung und Perspektiven 2001. Ergebnisse einer Arbeitstagung auf Schloss Reisenburg, 23./24.11.2000.

The progress in computer assisted surgery (CAS) is influenced by new technologies in imaging as well as by the input of the users. At present, CAS procedures are established in dorsal spine instrumentation, prosthetics and long bone surgery. Present status and future of CAS was a topic of an expert meeting at the Reisensburg castle. Imaging will speed up in the future using multi-detector techniques. C-arm navigation will gain more information using the 3D technology intraoperatively. CT based navigation procedures are standard in spine and will be established in pelvic surgery. CAS in robotics at the moment means the use of robot-assistance. A new concept is the modality-based navigated surgery, which can be used at various skeletal locations. Visualization of patient data will improve using 3D semi-transparencies with real time update. In the future it will be mandatory to find algorithms to fuse the different possibilities and techniques. A new concept of surgical training is necessary to teach CAS procedures. Therefore discussion must go on to improve these systems.

Quintessential adjustment of the cosmological constant

We construct a time dependent adjustment mechanism for the cosmological "constant" which could be at work in a late Friedmann-Robertson-Walker universe dominated by quintessence and matter. It makes use of a Brans-Dicke field that couples to the evolving standard-model vacuum energy density. Our explicit model possesses a stable late-time solution with a fixed ratio of matter and field energy densities. No fine-tuning of model parameters or initial conditions is required.