No abstract

Breast sentinel lymph nodes are still commonly assessed through complete lymph node dissections, which is a time-consuming and radical approach because the nodes are difficult to identify. To prevent false diagnosis and achieve accurate results, minimally invasive, imageguided procedures are applied and constantly improved. The purpose of this paper is to present the currently used imaging modalities ultrasound, fluorescence, single-photon emission computed tomography (SPECT), magnetic resonance imaging (MRI) and hybrid imaging methods and comparing their effectiveness for breast sentinel lymph node biopsy. A definition for an ideal imaging system combining efficient minimally invasive techniques with workflow considerations is also discussed. As a conclusion, upcoming imaging methods and their future outlook with areas of advancement are presented.

Techniques for intraoperative radiation therapy (IORT), the applications of tumor bed radiation immediately after surgery or utilising intracavitary access, have evolved in recent years. They are designed to substitute or complement conventional external beam radiation therapy in selected patients. IORT has become an excellent treatment option because of good long-term therapy outcomes. The combination of IORT with external beam radiation therapy has the potential to improve local control. The purpose of this paper is to present IORT techniques using gamma and electronic sources, as well as more conventional nuclide-based approaches and to evaluate their effectiveness. Common techniques for radiation of tumor cavities are listed and compared. Radionuclide IORT methods are represented by balloon and hybrid multi-catheter devices in combination with appropriate afterloaders. Electron beam therapy dedicated for use as intraoperative radiation system is reviewed and miniature x-ray sources in electronic radiation therapy are presented. These systems could further simplify IORT, because they are easy to use and require no shielding due to their relatively low photon energies. In combination with additional imaging techniques (MRI, US, CT and NucMed) the application of these miniature x-ray sources or catheter-based nuclide therapies could be the future of IORT.

Carbon nanotube (CNT) is a new technology used to generate gamma photons in X-ray tubes. CNTs, in comparison to other small X-ray sources, produce high X-ray intensities and as they are not based on a thermionic principle they considered cold electron sources with a very high conversion of electrical to photon energy. Their small size and other interesting properties could make them feasible for use in intraoperative radiation therapy applications. In this study, physical characteristics of the photon beam generated by the CNT-based X-ray source were assessed. A soft X-ray ionization chamber and a flat panel detector was used to measure dose and photon counts, respectively. The repetitively produced pulses had almost the same photon intensities with differences of less than 1% between them. For a typical selected pulse, the variation in the pulse amplitude was also insignificant, which shows a stable radiation exposure of the tube during the ON-mode. When moving from the center of the beam profile to the lateral distance of 25 mm, both intensity profile and dose profile showed a falling trend by a factor of almost 3 in the measured values.We also tested the miniature tube with our novel radiation beam shaping collimator designed for a possible application to treat larynx tumor, which showed the possibility of interventional radiation therapy using this miniature source. An endoscopic camera attached to the system can also make it possible to optically visualize the radiation exposed area.In conclusion, CNT-based X-ray source with suitable attached collimator to shape the beam of the source, seems to provide an opportunity to deliver radiation to a desired tumor area in minimally invasive image guided medical procedures mainly in the normal cavities of the body.