What can we learn from the neutron clinical experience for improving ion-beam techniques and high-LET patient selection?

摘要: Abstract Historically, improvements in radiotherapy have been mainly due to physical selectivity: beam penetration, collimation, dosimetry, treatment planning; and advances imaging. Neutrons were the first high-LET (linear energy transfer) radiation be used clinically showed improvement differential response of resistant tumors normal tissues. The benefits fast neutrons (and other forms high LET radiations) are their biological effects: a reduction OER, cell radiosensitivity related position mitotic cycle, cellular repair capacity (thus less importance fractionation). poor selectivity early neutron therapy beams introduced systematic bias comparison with photon treatments created negative perception for therapy. However, significant equipment resulted similar modern MV tumor types or sites where best therapeutic results obtained included inoperable recurrent salivary gland locally extended prostatic adenocarcinomas, slowly growing well-differentiated sarcomas. benefit some well-defined groups patients was demonstrated randomized trials. It estimated that about 20 % all could from (if delivered under satisfactory conditions). An important issue is selection who most radiations. same raised today radiations (e.g., 12C ions). reasonable assume would irradiation. Of course better ion enhances possibilities but this true both low-LET (i.e., moving ions photons protons, respectively). area research involves developing criteria identify specific suitable radiation. One promising technique measure RBE cancer population vitro head neck tumors. Modern molecular imaging allows identification hypoxic proliferative regions tumor. Special MRI examinations also able regions. A predictive test recently initiated, study non-repairable double strand breaks utility needs confirmed. extensive experience can greatly assist transition charged-particle