No qualified radiographer every tries to find T7, only students.. That is because it is pointless. Just do accurate collimation and use the illuminated field as your positioning guide. Look up my spinal series, lowest dose ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-4W1g0UVOGq0.htmlsi=2kxhsXDyyb29gnTC
No one knows where T7 is. No one tries to find it and I laugh when students try to find it. It is useless because a chest xrays success does not depend on where T7 is. It is an example of a positioning system developed in 1920 still impacting us today even after we invented the light beam diaphragm. Instead, collimate accurately to the cassette or smaller, then ensure the tops of the lungs appear on the top of the radiograph using judgement. I would freak out radiologists by collimating the breasts off women's lateral chests. Why is that not standard practice? We have the technology. I rotate the collimator then lean them forward then use judgement