A NOVEL TISSUE EQUIVALENT PHANTOM FOR HADRON THERAPY
Lead Research Organisation:
University of Liverpool
Department Name: Physics
Abstract
A thin silicon sensor will be integrated in a mechanical system for scanning through a tissue equivalent liquid phantom for providing extremely accurate information on the dose deposited by a hadron therapy beam as a function of depth into the phantom and on the position in the plane perpendicular to the beam axis. This will allow a precise knowledge of the dose delivered to the patient (3d dose mapping) with unprecedented spatial resolution and speed. The dose deposited in depth by a hadron therapy beam in the human body follows a typical distribution that terminates with the high energy release called Bragg peak at the end of travel. This high energy deposition is exploited to maximise the effect to the cancer while giving limited amage to the surrounding helthy tissue. The accurate knowledge of the energy deposited by the beam is key to planning the treatment on individual patients. Also, the online monitoring of the Bragg peak position stability during treatment is essential for the success of the treatment.
Thanks to the fast response of silicon detectors, the Bragg peak scan will provide real-time information to the operators on the dose to be released by the therapy beam in the target and surrounding tissue. This phantom makes use of a thinned silicon detector to enhance the accuracy of the scan. The precision of the reconstructed profiles can be selected to be as fine as 10 microns (this accuracy comes without cost or hardware complexity penalties). This instrument makes use of a single sensitive element (the silicon detector) moved by a precision motor in axis with the therapy beam. The energy deposition of the beam is continuously measured by the sensor while moved from the entrance point of the phantom to the back end. The beam is stopped within the phantom volume and the scan delivers the energy deposition profile with great accuracy and in real time. This instrument would represent a significant improvement with respect to existing phantoms because of its high spatial resolution and real time response. The precision would prove very valuable at the planning stage of the treatment and the speed for real-time feedback. It could be used at any hadron therapy centre alone or in combination with other existing beam monitoring equipment.
Thanks to the fast response of silicon detectors, the Bragg peak scan will provide real-time information to the operators on the dose to be released by the therapy beam in the target and surrounding tissue. This phantom makes use of a thinned silicon detector to enhance the accuracy of the scan. The precision of the reconstructed profiles can be selected to be as fine as 10 microns (this accuracy comes without cost or hardware complexity penalties). This instrument makes use of a single sensitive element (the silicon detector) moved by a precision motor in axis with the therapy beam. The energy deposition of the beam is continuously measured by the sensor while moved from the entrance point of the phantom to the back end. The beam is stopped within the phantom volume and the scan delivers the energy deposition profile with great accuracy and in real time. This instrument would represent a significant improvement with respect to existing phantoms because of its high spatial resolution and real time response. The precision would prove very valuable at the planning stage of the treatment and the speed for real-time feedback. It could be used at any hadron therapy centre alone or in combination with other existing beam monitoring equipment.
| Description | The feasibility of remarkably improving the precision of treatment planning for cancer with the hadron-therapy approch. |
| Exploitation Route | Being further devoped in collaboration with hadron therapy treatment providers and installed in running faciioties. |
| Sectors | Electronics,Healthcare |
| Description | In advanced discussion with a cancer therapy provider for further investigation/use in near future therapy centres. |
| First Year Of Impact | 2015 |
| Sector | Healthcare |
| Impact Types | Cultural |
| Title | Tissue equivalent phantom |
| Description | The tissue equivalent phantom is constituted by a motorised mechanical system for scanning the penetration range of a charged particle beam in a volume of tissue equivalent liquid (e.g. water). The sensing device is a single channel (pad diode) or a multi-channel (microstrip or pixel detector) semiconductor detector (e.g. silicon). The position of the sensor during the scanning is logged to correlate with the output data of the sensing device that measures the energy deposited locally by the particle beam. This results in a very precise measurement of the local energy deposited in tissue equivalent material by the charged particles crossing the volume. In particular, it determines the location of the Bragg peak (the high relative energy release in matter by a stopping charged particle). It determines therefore the range (the distance travelled by the charge particles before stopping in the volume) and the energy deposited along its path. In the case of a single PAD diode, the measurement is performed in 1 dimension (depth in tissue equivalent material), while in the case of pixelated sensing devices the measurement is performed in three dimension (3D), with the determination of the range and energy deposition with the volume divided in small units (voxels). The use of semiconductor sensors allows unprecedented precision for this type of measurement. The 3D device can also be paired by another (or more) 3D device arranged in parallel to the first one and at a fixed distance in the direction of the motion to add directional information on the particles crossing the volume. |
| IP Reference | GB1701853.2 |
| Protection | Patent granted |
| Year Protection Granted | 2017 |
| Licensed | No |
| Impact | Waiting for licensing. Increase in the quality ot the cancer treatment planning fir hadron (proton) therapy centres. |