Stereotactic radiosurgery method and apparatus

A stereotactic radiosurgery apparatus comprising:

• means for generating a radiation beam toward a patient;
• first filter means for forming said radiation beam into a first beam of stereotactic radiation;
• second filter means for forming said radiation beam into a second beam of radiographic radiation;
• means for positioning one of said first and second filter means in a predetermined sequence in a path of said radiation beam between said generating means and the patient;
• and
• means for detecting said second beam which passed through said second filter means and the patient.

A stereotactic radiosurgery method comprising the steps of:

• generating a radiation beam toward a patient;
• positioning one of a first filter for stereotactic radiation and a second filter for radiographic radiation in a predetermined sequence in a path of the radiation beam directed toward the patient;
• and
• detecting the radiation beam which passed through the second filter and the patient.

A radiation beam controlling apparatus comprising:

• a holder on which a first filter for stereotactic radiation and a second filter for radiographic radiation are mounted;
• and
• a rotator for rotating said holder;
• wherein respective centers of said first and second filters are substantially positioned on an imaginary circle concentric with a rotational center of said holder, said imaginary circle intersecting a path of a primary radiation beam from a radiation source.

A radiation beam controlling device comprising:

• a first filter for stereotactic radiation;
• a second filter for radiographic radiation;
• and
• means for holding said first filter and said second filter so that respective centers of said first and second filters are substantially positioned on an imaginary circle concentric with a rotational center of said holder, said imaginary circle intersecting a path of a primary radiation beam from a radiation source.