The aim of our research activities is to promote the development and utilization of cyclotron-produced radiopharmaceuticals by:
- conducting basic research allowing for the development of new labeling agents, new labeling methods, design and synthesis of novel PET biomarkers with high "chemical resolution".
- ameliorating existing methods in order to study physiological, biochemical and pharmacological functions at a molecular level, both with healthy and sick subjects.
- prompting technical developments which support the above-mentioned activities such as targetry development for the production of radioisotopes, automation of radiochemical processes, etc. These developments can be routinely used in PET centers.
Accelerators are devices that accelerate charged particles to bombard a targets containing stable isotopes as precursors. The radioisotopes are produced by a nuclear reaction. Negative ions are produced at the center of the machine. The negative ions are subjected to a fixed magnetic field and gain energy due to a high voltage alternating electric field induced on a pair of electrodes called dees.
The particles are accelerated in spiral paths inside the two semicircular flat evacuated metallic dees. When reaching high energy the charged particles are bent out to bombard the target. At Hadassah Hospital, the "physiological" PET radioisotopes are produced with the IBA accelerator (Cyclone 18/9). Cyclone 18/9 is a fixed-energy cyclotron, accelerating H- ions up to 18MeV and D- up to 9MeV. The beam intensity is 80*A for protons and 35 for deuterons. Cyclone 18/9 includes eight exit ports allowing eight targets to be simultaneously mounted on the cyclotron. The Hadassah Cyclotron contains six targets for the production of C-11, F-18, O-15, and N-13.
Routine production of PET biomarkers:
(F-18) FDG, (O-15) WATER, (N-13) NH3, (C-11) DEPRENYL, (F-18)F DOPA, (C-11) CHOLINE, (C-11) METHIONINE.
In the last two years, several technical systems were developed in order to ensure a safer and easier production of PET radioisotopes and biomarkers. In order to reach optimal safety conditions in the radiochemistry laboratory and to get online information regarding radioisotopes production and radiochemical processes, a gas waste decay system and an online monitoring system were built in our laboratory. These systems allow for a comprehensive evaluation of radiochemical processes and provide an effective solution for the control of various aspects of production and radiation safety in a cyclotron/radiochemistry facility. A semi-automated system for the radiosynthesis of F-18 F-DOPA was designed and used for routine production of F-DOPA. An automated system for the dispensing of PET radiopharmaceuticals was also built. The use of this system decreases the exposure of personnel and allows for automated sterile dispensing of high doses of radioactive biomarkers.
The PET (Positron Emission Tomography) scanner is a device displaying the distribution of radioactivity in the body of the patient following administration of a positron-emitting tracer produced by the cyclotron. The scanner consists of rings of detectors which detect 511 kev photons generated by positrons emitted by the radiotracer and interact with electrons in the body of the patient. The PET scanner is linked to computers which control its operation. The computers are also required to perform the calculations necessary to obtain a 3-dimensional set of tomographic images which provide a quantitatively accurate map of the radioactivity in the patient's body, and can be used by physicians for diagnosis. The PET scanner at the Hadassah University Hospital PET Center is the Positron Corporation (Houston, Texas) HZL/R PET scanner. This scanner has an axial field of view of length 16.6cm, and has in-plane spatial resolution 5.8 mm, with axial spatial resolution 6.3mm.
PET-CT: A New Machine Essential To The Treatment Of Cancer
This ultra-modern machine, essential to cancer treatment, has been installed in the Department of Medical Biophysics and Nuclear Medicine at Hadassah Hebrew University Hospital [GE Discovery ST PET/CT scanner (in-plane) resolution 6.2 mm, axial resolution 5.0 mm]. This equipment, both a PET and a CT machine (or Positron Emission Tomography/Computer Tomography scanner), has been operational since the end of March 2004. Hundreds of combined tests have been performed with this state-of-the-art scanner, the most sophisticated in Israel, in the field of oncology. Its main objectives are the diagnosis and staging of cancer in all organs and the results of therapy on each specific cancer. PET major benefit lies in its ability to assess the viability of lesions in these organs (active tumor or not). Combination of PET with CT helps define more accurate location of PET findings.
Thanks to the rich knowledge acquired with the older PET model, and a close collaboration with the Department of Radiology, the staff in charge of the new scanner was able to quickly learn to operate and to interpret the obtained images. Hadassah Hospital has vast experience in PET operation, as well as experience with a similar, less sophisticated hybrid machine. PET activity started as early as 1995 in Hadassah - Our PET was the first PET machine ever to be installed in Israel. For the first year and a half, PET was used only for cardiac tests (about 500 tests were performed) assessing blood supply and viability of the heart muscle after ischemia. Since July 1997, PET oncological scans are also being performed with the help of a labeled radiopharmaceutical (FDG) produced by an in-site cyclotron. Cancerous tissues are enhanced compared to healthy tissues and a lesion appears as a hot spot on the images.
The Hawkeye is an X-ray transmission sytem mounted on the slip-ring gantry of a GEMS Millenniun VG gamma camera. The X-ray imaging system is composed of an X-ray tube and a set of detectors located on opposite sides of the gantry rotor that moves around the patient along with the nuclear detectors. A cross-sectional anatomical transmission map is acquired as the system rotates around the patient in a manner similar to a third-generation computerized tomography (CT) system. Following transmission, single-photon emission tomography (SPECT) or positron emission tomography (PET) coincidence detection images are acquired and the resultant emission images are thus inherently registered to the anatomical maps.