The use of irregular fields formed for each individual patient became a routine clinical method of irradiation of systemic malignant tumors. It allowed one to improve the therapeutic effectiveness of radiation therapy. A set for irregular field irradiation using gamma-beam therapy apparatus was developed. The set includes equipment for preirradiation preparation, for irradiation and its control. The trials of the set have shown that its parameters meet all necessary requirements. The set was recommended by the USSR Ministry of Health into clinical practice.