Method and device for controlling dosage application during irradiation

A method for controlling the dose application during irradiation of a moving target volume in a body with an energy beam using a scanning method, the method comprising

• creating an irradiation plan including a plurality of grid positions (i, 1<=i<=N) of the target volume for one or more irradiation cycles (j, 1<=j<=J), a grid-position-dependent nominal particle fluence being defined in the irradiation plan for the irradiation of each of the grid positions;
• capturing a motion of the body during the irradiation in order to determine a motion of the grid positions during the irradiation;
• and
• performing the irradiation by successively scanning the individual grid positions with the energy beam using a particle energy and a particle fluence that are controlled as a function of the grid position, so as to apply a grid-position-dependent dose at the corresponding grid position, the scanning including:
• i1) prior to the irradiation of an i-th grid position of the plurality of grid positions, calculating a dose that was already received by the i-th position during the irradiation of previous grid positions (k,1<=k<i) during the irradiation cycle using the motion data;
• i2) prior to the irradiation of the i-th grid position, calculating a compensation value (ΔDi) for the i-th grid position based on the dose that the i-th grid position is determined to have already received during the irradiation of the previous grid positions (k, 1<=k<i);
• i3) prior to the irradiation of the i-th grid position, calculating a compensated particle fluence (Ficomp) for the i-th grid position based on the compensation value (ΔDi) for the i-th grid position and a nominal particle fluence (Finom) for the i-th grid position;
• and
• i4) irradiating the i-th grid position with the compensated particle fluence (Ficomp) determined for the i-th grid position, steps i1) through i4) being carried out for the plurality of grid positions (1<=i<=N).

An irradiation device for irradiating a moving target volume in a body with an energy beam using a scanning method, the irradiation device comprising an irradiation planning device adapted to process data from a time-resolved imaging system and, based on the processed data, to create and store an irradiation plan including a plurality of grid positions (1<=i<=N) of the target volume for one or more irradiation cycles, the irradiation plan including, for the irradiation of each of the grid positions, a reference data set containing at least the position data of the respective grid position and a grid-position-dependent nominal particle fluence (Finom) to be applied;

• a motion sensing device configured to capture a motion of the body during irradiation in order to determine a motion of the grid positions during the irradiation;
• a therapy control system adapted to control the irradiation device so as to successively scan individual grid positions by the beam with a particle energy and a particle fluence that are controlled as a function of the grid position, so as to apply a grid-position-dependent dose at the corresponding grid position, and so as to read out and change, during the irradiation, the data sets of the irradiation plan that were stored prior to the irradiation, the scanning including:
• i1) prior to the irradiation of an i-th grid position of the plurality of grid positions, calculating a dose that was already received by the i-th position during the irradiation of previous grid positions (k, 1<=k<i) during the irradiation cycle using the motion data;
• i2) prior to the irradiation of the i-th grid position, calculating a compensation value (ΔDi) for the i-th grid position based on the dose that the i-th grid position is determined to have already received during the irradiation of the previous grid positions (k, 1<=k<i);
• i3) prior to the irradiation of the i-th grid position, calculating a compensated particle fluence (Ficomp) for the i-th grid position based on the compensation value (ΔDi) for the i-th grid position and a nominal particle fluence (Finom) for the i-th grid position;
• and
• i4) irradiating the i-th grid position with the compensated particle fluence (Ficomp) determined for the i-th grid position, the therapy control system being adapted to perform the steps i1) through i4) successively for the plurality of grid positions (1<=i<=N).