Microdosimetry study of a new radiation therapy method based on proton minibeams

ended

Radiotherapy (RT) is the medical use of ionising radiation to treat cancer. The main challenge is to deposit a high enough (curative) dose in the tumor while risk organs near the tumour remain at tolerable doses. About 52% of cancer patients receive RT at least once during treatment. The RT has achieved great success in the cure or palliation of various cancers, but for improving this statistic, new treatment modalities as proton radiotherapy (PT) are rapidly expanding. PT achieves very high dose conformity around the target, allowing a better protection of the organs at risk (decreasing radiation side effect). However, using PT the dose delivered to a tumour is still conditioned by the dose that can be tolerated by the surrounding normal tissues. This is particularly critical for certain types of radioresistant tumours, such as hypoxic tumors, for those localized near organs at risk or sensitive structures (e.g. the spinal cord), and paediatrics cancers. For these types of cancers with poor prognosis it is imperative to find new RT approaches that reduce the normal tissue complication probability (NTCP). A recent novel therapy aim to increase the effective dose therapies by using a distinct dose delivery method based on proton minibeams (pMBRT). To implement this promising technique at clinical centers, microdosimetric data are required on the radiation quality aspects of proton minibeams to take advantage of their enhanced relative biological effectiveness versus conventional radiotherapy sources. Currently there are only one array of microdosimeters, as the proposed herein, capable of measuring these parameters in proton therapy. This is the challenge where a candidate approach is preferred.