A characteristic-line X-ray source is proposed for dual energy subtraction imaging of the human coronary arteries. The source is based on the production of the K alpha lines in a rotating metal compound target bombarded by a high energy electron beam. The electron beam is produced in an inexpensive, compact, single resonator RF accelerator. Predicted available X-ray fluences are compatible with imaging of the coronary arteries after an intravenous injection of iodine contrast agent. Thus, this technique has the potential for greatly reducing patient risks in diagnostic and follow-up angiography procedures. Phase I will comprise an experimental investigation of K X-ray yields and spectral purity of the radiation produced from a target bombarded by a low current, high energy e-beam, and computer calculations of signal to noise ratio in the subtraction image for optimization of X-ray spectral characteristics. The study will culminate in the conceptual design of a K alpha X-ray source suitable for clinical use.