Medical imaging, navigation, and robotics - technical solutions for clinical problems

Abstract

Medical imaging, navigation, and robotics are technical solutions which can be used to solve clinical problems. They can be used for personalizing the treatment, for accurate targeting, for increasing therapeutic effectiveness, and for decreasing procedure time. A main driver for the increased usage of these technologies is the trend to minimally invasive procedures. In the last two decades, there are many examples of minimally invasive procedures in surgery and interventional radiology replacing more invasive procedures. In conventional open surgery, the surgeon operates on the target tissue through a large incision. This large incision provides the surgeon as well as the assistant with direct access to the tissue, both visually and tactilely: The surgeon is in direct contact with the tissue and uses only simple instruments. During minimally invasive surgery, however, the operative situation is completely different, although the principle of treatment is not changed. Access to the pathology is generated through (several) small incisions. Unfortunately, these small incisions do not allow a direct contact of the surgeon with the target organ. Instead, imaging systems like endoscopes are used to provide a view to the operative target. Tools used to manipulate the tissue must also fit through these incisions and are thus more complex in structure and more difficult to use. In interventional radiology, the access to the target can be even smaller. Therapy is delivered through thin needles or catheters only. Tactile and visual feedback is thus even more indirect than in minimally invasive surgery and relies on non-optical imaging methods like X-ray, ultrasound, CT, and MRI. Nevertheless, the advantages of the smaller incisions for the patient (less pain, shorter stay in hospital, better cosmetics, and reduced risk of wound infection) usually outweigh the more complicated and less ergonomic working conditions of the medical professionals. The use of medical imaging also offers further advantages. Procedures can be planned in detail before the operation based on CT or MRI images. As well as morphological image information spatially resolved biological or physiological information obtained from molecular imaging methods like PET or SPECT can also be taken into account. However, in order to accurately execute the planned procedure in the operating room, navigation and robot technology must be used in surgery as well as in interventional radiology. These technologies are of crucial importance if a multi-modal treatment plan involving not only surgery, but also other treatment modalities like radiotherapy or chemotherapy, needs to be carried out. Surgical navigation systems measure the intra-operative position of a surgical instrument and relate it via a suitable registration method to the pre- or intra-operative image and the surgical plan. The surgeon can see where the instrument is positioned in the patient, without real-time imaging, and can thus operate according to the plan. Navigation systems have been introduced in the 1990 s first in neurosurgery, but are now used routinely also in ENT surgery, orthopedics, spine surgery, and traumatology. In interventional radiology, navigation systems are not as wide-spread as in surgery, since real-time imaging devices are often preferred and available. However, robots can offer ways to handle instruments in the imaging system, where the interventionist cannot work either due to space restrictions or due to X-ray radiation. However, navigation systems as well as medical robots are intrinsically complex systems. In contrast to traditional operations they require a significant investment in technology as well as training. Therefore, both technologies, navigation and robotics, have to compete with simpler and cheaper methods of reaching the same goal of delivering the correct treatment to the correct place. The potential of surgical navigation and medical robotics is enormous. Nevertheless, before robots will be used routinely it must be proven that the quality of the medical procedures is increased and at the same time the cost of the treatment can be reduced.