New Technology Is Making a Difference in the Fight Against Cancer
Rapid technological progress in recent years has led to an evolution in all areas of medicine and has significantly influenced radiation oncology. Today, a new frontier in radiation therapy is represented by the hadrontherapy, which is the use of protons and atomic nuclei (ions) called hadrons (from the Greek hadrós, strong) that are subjected to a strong nuclear force.
The advantages of hadrontherapy compared to traditional radiotherapy are:
The release of energy (and thus the destruction of cells) is done selectively, targeting only cancer cells. The damage incurred in the body on initial penetration is relatively small and significant release of energy is confined only to the vicinity where the cancer is located (a phenomenon referred to as the Bragg Peak). This maximizes the destruction of cancerous tissues while minimizing collateral effects on healthy tissues
The beam of hadronic particles remains collimated as it penetrates the biological material. The high collimation of the beams of hadrons further minimizes damage to healthy tissues
The energy release mechanism for hadrontherapy causes a large amount of breaks on the chemical links present in biological macromolecules, especially DNA. The latter has the ability to repair itself, but if the number of broken links is excesive it loses its function of self-reparation and the cells remain inactive and die. In conventional radiotherapy the DNA damage is modest; on the contrary, in the hadrontherapy with carbon ions the number of breaks allows the destruction even of tumors resistant to conventional therapy.
Together these three benefits result in a significant destructive effect on biological tissues, for which reason the target (tumor) must be positioned with a degree of accuracy which is much greater than that associated with conventional radiotherapy.
Synchrotron and hadrontherapy are ideally suited to treat tumours that are deep-seated, located close to critical organs and respond poorly to conventional photon or electron radiotherapy.
cancer of the prostate and rectum (pelvic district)
melanoma of the rectum and vagina
abdominal area - cancer of the liver and bile
cranial base cancer
central nervous system
tumors of epithelial origin
eyeball and eye socket
head and neck
paranasal sinuses and nasal cavities
bone and soft tissue
CNAO’s ‘High Technology’ components consist of a set of accelerators and transport lines of particle beams. The beams are generated by sources that produce carbon ions and protons. The most important accelerator machine is the Synchrotron. The synchrotron at CNAO is a prototype resulting from the research in high energy physics made possible through the collaboration of the Istituto Nazionale di Fisica Nucleare (INFN), CERN (Switzerland), GSI (Germany), LPSC (France) and of the University of Pavia University (Italy). It is based mostly on Italian technology.
The synchrotron is a “donut” 80 meters long with a diameter of 25 meters. In two areas inside the circumference the beams of particles are created in devices called “sources”, which contain plasma formed by the gas atoms that have lost their electrons. Using magnetic fields and radio frequency pulses, these atoms are extracted and the protons and carbon ions are selected. In this way “packages” composed of beams -each one containing billions of particles- are formed.
These packages are pre- accelerated and sent to the synchrotron where, initially, they travel at about 30,000 kilometers per second. Subsequently they are accelerated to kinetic energies of 250 MeV for protons and 480 MeV for carbon ions (the MeV, equivalent to one million electron volts, is the unit of energy used in nuclear and atomic scale phenomena).
The particle beam is accelerated in the synchrotron and travels about 30,000 kilometers in a half second to reach the desired energy. The beams are then sent to one of the three treatment rooms. Above this station there is a magnet of 150 tons which bends 90 degrees the particle beam and directs it from above to the person to be healed.
The beam that strikes the cells of the tumor is like a “brush” that moves in a manner similar to that of electrons in a TV and acts with a precision of 200 micrometers (two tenths of a millimeter).
This accuracy is achieved by means of:
Constant monitoring of the patient to follow any movements of the body (breathing, for example) that can change the location of the tumor, using infrared cameras to measure movement in a three-dimensional way
Two scanning magnets that, based on feedback of the beam monitoring system, move the “brush” along the outline of the tumor
In this way, section by section, the tumor is destroyed. The transition from one section to another deeper section is achieved by increasing the beam energy. The entire radiation lasts a few minutes.