The mobile Electron Accelerator
for intra Operative Radiotherapy (IORT)
- Technical IORT presentation
Intraoperative radiotherapy or IORT consists in treating tissue suffering from neoplastic processes, made accessible by surgery, with an electron beam.
After an experimental stage, in the sixties last century IORT cleared and set its election criteria and in the mid nineties, thanks to specific equipment enabling validation of new protocols, began to spread outside research environments. IORT has shown an evident capacity for the local control of cancer and can be applied to all solid tumours.
The LIAC (Light Intraoperative Accelerator) is a machine created after carefully analysing limits set by what has to be done in a surgical environment; its prerogatives are the excellent possibility of being included in any operating theatre with no need to change existing structures.
Its weight, extremely limited (400 kg), enables use on all floor types with no need to reinforce it and thanks to its size (200x80x180 cm) and manoeuvring capacity it can be transported in normal lifts carrying stretchers. The electronic beam energy (10 or 12 MeV) can satisfy almost any kind of therapy of a minimum complexity level to obtain use permits, while the amount of radiation produced means minimum time (50-100 seconds) needed to carry out treatment.
The LIAC also has a supply stabilising system providing short and long term stability like conventional accelerators, and its electron beam means execution doses are precise like with completely conventional methods and instruments. . - Using the LIAC
The LIAC was designed to operate in the entire range of intraoperative therapies; it is practical to use in those applications where rapid positioning and considerable radiation volume do not lengthen short operations; however, its energy and agility correspond excellently to the needs of more laborious applications like those on the abdomen and mediastinum.
Special care was taken over making therapy easier, where positioning is more delicate; for example the Miles technique.
We must point out that the time needed for a radiation therapy is independent of surgery complexity and trained staff do not take longer than 5-7 minutes to supply radiation. - Safety in and outside the operating theatre
A lot of care was taken over machine safety; the position of mobile beam screening is monitored continuously and blocks the machine if it is misaligned. There are far more optical and acoustic signals than the laws in force require.
Finally, the LIAC has excellent connectivity as it can be connected to a local network to exchange data; the machine is compatible with all main protocols in use.
| Technical characteristics | ||||
|---|---|---|---|---|
| - Nominal energies 10 MeV Model | 4,6,8,10MeV | - Beam current | 1.5mA | |
| - Nominal energies 12 MeV Model | 6,8,10,12MeV | - Long term stability | <3% | |
| - Surface dose | >=85% | - Short term stability | <0,3% | |
| - Field uniformity | <=5% | - X-ray contamination | <=0,3% | |
| - Field symmetry | <=3% | -Reproducibility of dosimetric system | <=1% | |
| -Applicator sizes | 3,4,5,6,7,8,9,10 cm | -Linearity of dosimetric system | <=1% | |
| -Source surface distance (SSD) | 60cm | -Scattering filter | 80 micrometer | |
| -Dose rate | 10/15 Gy/min | -Max operating temperature | 25C° | |
| -Pulse repetition frequency | 10-50Hz | -Air dissipated power | 0.8kW | |
| -Pulse lenght | 2,5 microsec. | -Electrical power requirements | 230V, 50Hz, 2.5kVA | |
| Weights | ||||
|---|---|---|---|---|
| - Accelerator | 400kg | - Control unit | 100kg | |
| Dimensions | ||||
|---|---|---|---|---|
| - Accelerator | 210 x 80 x 180cm | - Control unit | 60 x 80 x 120 | |
