Biomagnetic field measuring apparatus using squid magnetometers for evaluating a rotational property of a current in a subject

A biomagnetic field measuring apparatus for evaluating a rotational property of a current in a subject to be tested, comprising:

• a bed for holding the subject to be tested;
• a plurality of magnetometers for measuring a normal component of a biomagnetic field generated from the subject be tested;
• a cryostat for holding the plurality of magnetometers at a low temperature;
• means for holding said cryostat;
• a driving circuit for driving the plurality of magnetometers;
• an arithmetic operation unit for collecting output signals from said driving circuit as a measured biomagnetic field and for operating arithmetically on the measured biomagnetic field;
• and
• display means for displaying a result obtained by said arithmetic operation unit;
• wherein said arithmetic operation unit calculates current arrows at measurement positions of the measured biomagnetic field by partially differentiating the measured biomagnetic field, discretely curvilinearly integrates a tangential component of the current arrow contacting a circumference which is at an arbitrary distance from each of the measurement positions so as to obtain an integrated value for each of the measurement positions, and calculates a map diagram which is obtained by contour lines each connecting equal integrated values;
• and
• wherein said display means displays said map diagram.

A biomagnetic field measuring apparatus for evaluating a rotational property of a current in a subject to be tested, comprising:

• a bed for holding the subject to be tested;
• a plurality of magnetometers for measuring a normal component of a biomagnetic field generated from the subject be tested;
• a cryostat for holding the plurality of magnetometers at a low temperature;
• means for holding said cryostat;
• a driving circuit for driving the plurality of magnetometers;
• an arithmetic operation unit for collecting output signals from said driving circuit as a measured biomagnetic field and for operating arithmetically on the measured biomagnetic field;
• and
• display means for displaying a result obtained by said arithmetic operation unit;
• wherein said arithmetic operation unit calculates current arrows at measurement positions of the measured biomagnetic field by partially differentiating the measured biomagnetic field, discretely curvilinearly integrates a tangential component of the current arrow contacting a circumference which is at an arbitrary distance from each of the measurement positions so as to obtain an integrated value for each of the measurement positions, calculates a minimum value and a maximum value of the integrated values, and calculates a difference value between the absolute value of said minimum value and said maximum value;
• and
• wherein said display means displays at least one of said minimum value, said maximum value and said difference value.