Abstract: Provided are a method of deciding the risk of obstructive sleep apnea syndrome capable of deciding the risk of a subject to become obstructive sleep apnea syndrome objectively and easily in a short time, its program and an X-ray diagnostic system having the program. The method includes detecting at least the hyoid bone, sella S, gonion Go and menton Me by lateral head and neck radiography of the subject; and deciding whether the center of the body or the whole of the body of the detected hyoid bone is included in an area above a perpendicular drawn toward the extended line of the segment S-Go from Me or not.

Abstract: Provided is an X-ray radiographic apparatus that can take a lateral cephalometric radiograph, a posteroanterior cephalometric radiograph, etc. under the same state of the tilt in the front-rear direction of the head of a subject easily and with high reproducibility, and is free of risks associated with the use of an infraorbital point pointing bar. The X-ray radiographic apparatus includes: a pair of arms provided facing each other with a reference line therebetween; ear rods provided to mutually facing inside surfaces of the pair of arms; a head tilt setting device for setting the tilt in the front-rear direction of the head of the subject provided on one arm, and a horizontal plane verification mechanism provided on the head tilt setting device or outside of the head tilt setting device.

Abstract: Provided are a method of deciding the risk of obstructive sleep apnea syndrome capable of deciding the risk of a subject to become obstructive sleep apnea syndrome objectively and easily in a short time, its program and an X-ray diagnostic system having the program. The method of includes detecting at least the hyoid bone, sella S, gonion Go and menton Me by lateral head and neck radiography of the subject; and deciding whether the center of the body or the whole of the body of the detected hyoid bone is included in an area above a perpendicular drawn toward the extended line of the segment S-Go from Me or not.

Abstract: There is provided a method of calculating an index for deciding the necessity of surgically operating on the jaw in orthodontic treatment wherein an index for deciding the necessity of surgically operating on the jaw which becomes objective materials for a dentist to decide the necessity of surgically operating on the jaw of a patient in orthodontic treatment of the patient can be calculated easily, and by appropriately combining the results of other inspection methods, the dentist is able to diagnose easily with high objectivity and correctness, moreover with a short period of time, and its program. Using the distance (S?A) between S and A, the distance (S?Xi) between S and Xi (i is an integer from 1 to 4. X1=B, X2=Pog, X3=Gn and X4=Me.) and the distance (Go?Xj) between Go and Xj (j is an integer from 1 to 4. j=i or j?i.

Abstract: There is provided a method of calculating an index for deciding the necessity of surgically operating on the jaw in orthodontic treatment wherein an index for deciding the necessity of surgically operating on the jaw which becomes objective materials for a dentist to decide the necessity of surgically operating on the jaw of a patient in orthodontic treatment of the patient can be calculated easily, and by appropriately combining the results of other inspection methods, the dentist is able to diagnose easily with high objectivity and correctness, moreover with a short period of time, and its program. Using the distance (S?A) between S and A, the distance (S?Xi) between S and Xi (i is an integer from 1 to 4. X1=B, X2=Pog, X3=Gn and X4=Me.) and the distance (Go?Xj) between Go and Xj (j is an integer from 1 to 4. j=i or j?i.