Abstract: A manual irradiation loading apparatus and method of irradiating a localized area of a human or animal patient using the manual irradiation loading apparatus. The irradiation loading apparatus comprises a radiation shielding material having at least one cable-receiving passage therethrough and a cable having a radiation source provided on one end thereof received in the cable-receiving passage. The irradiation loading apparatus is also provided with a catheter-receiving passage for joining a catheter positioned in a catheterized patient to the cable-receiving passage to permit the end portion of the cable having the radiation source thereon to be advanced into the catheterized patient for radiation treatment. In one embodiment, the irradiation loading apparatus includes a main shielding body and a removable, interchangeable cartridge to permit the irradiation loading apparatus to be used with different radiation sources.