Caren van Roekel

36 Chapter 2 radioembolization of colorectal cancer liver metastases. Moreover, beta- blockers can reduce stress hormone-mediated invasion of tumor cells (67). Besides beta-blockers and aspirin, proton-pump inhibitors are often given during the first week before and continued up to a month after treatment, as prophylaxis for gastrointestinal ulcer formation. Heparin, according to local guidelines in interventional radiology, is given for thrombosis prophylaxis during treatment. If a vasospasm occurs during the procedure, it is indicated to give a vasodilator intra-arterially. Neuro-endocrine tumors can rapidly release a large amount of vasoactive substances after radioembolization. This may lead to a carcinoid crisis with flushing, hypertension and tachycardia, followed by hypotension and possibly death (68). To prevent a carcinoid crisis, somatostatin analog prophylaxis intravenously may be indicated. When patients are in pain, intravenous analgesia should be considered during the procedure, according to local interventional radiology guidelines. 5.3. Dose administration All three types of microspheres are provided in a vial. The administration systems are quite different from each other, but they all have two lines: one that connects the vial with the microcatheter, and one through which the nuclear physician can inject a diluting solution in the vial (i.e. saline, sterile water or 5% glucose) (9, 69, 70). There are significant differences in administration techniques between 90 Y resin microspheres, 90 Y glass microspheres and 166 Ho microspheres. 90 Y resin microspheres should be administered very carefully with a flow rate of no more than 5 mL per minute, to allow for optimal distribution in the tumor microvasculature. The administration usually takes up to 20 minutes. While administrating, the interventional radiologist should check for slow flow or stasis, by administrating small aliquots of contrast fluid and microspheres alternately. When stasis occurs, the procedure should be terminated to prevent reflux (9). It was hypothesized that sterile water, which was injected