MRI apparatus with improved thermal control system and method for operating said thermal control system

MRI apparatus with an enhanced thermal control system, the said apparatus comprising:

• a static magnetic field generation unit with at least two magnetic poles supported one opposed to the other at a predetermined distance by a yoke and forming a gantry for housing an object to be imaged;
• at least one heater for heating the said magnetic poles and/or the said magnetic yoke;
• one or more temperature sensors measuring the temperature of the at least one pole and/or of the yoke;
• a thermal control unit, comprising:
• a processing unit, with a memory in which a control software is loaded or loadable, the said control software being executed or executable by the said processing unit;
• said processing unit having input ports for receiving the temperature measurement signals from the said one or more temperature sensors;
• said processing unit having output ports for feeding driving signals to the said at least one heater;
• the said control software comprising the instructions for configuring the said processing unit to generate the said driving signals of the said at least one heater as a function of the signals relating to the measured temperature by the said one or more sensors, and in which
• one or more temperature sensors are associated to each of the poles and to the yoke;
• one or more heaters are associated and in thermal contact to each of the poles and to the yoke,
• in the said control software, the instructions being coded for configuring the said processing unit to carry out two different control phases:
• a first yoke heating phase for heating the yoke at a predetermined working temperature of the yoke;
• a second pole/poles temperature control phase which is started upon reaching of the said working temperature of the yoke by the first yoke heating phase and which second phase provides the driving of the heaters associated to the pole/poles till a predetermined working temperature of the said pole/poles has been reached;
• the said second pole/poles temperature control phase being carried out continuously or steadily during the execution of image acquisitions by the MRI apparatus, while the said yoke heaters are deactivated;
• the said yoke heaters being reactivated if the yoke temperature drops below the said yoke working temperature and till the yoke working temperature has been reestablished.