1. Patients without adequate pre- assessment tests. Appropriate scans (MRI, CT or ultrasound) and relevant blood tests (including full blood count, liver function tests, urea and electrolytes, and tumor markers) must be available to the XYTOS assessing doctor. Tests must be current.
2. Patients without a doctor who is prepared to follow-up when the patient returns home.
3. Patients under the age of 18.
4. Pregnant or potentially pregnant patients. Women of childbearing age must be tested for pregnancy before treatment and must not contemplate pregnancy within 12 months of XPDT/XSDT.
5. Clinically depressed patients, who are unlikely to complete the treatment.
6. Patients with advanced aggressive widespread cancer (i.e. terminal patients), unless the patients treating doctor is in no doubt that the patient is still strong enough to handle the therapy.
7. Patients on supplemental oxygen most of the time.
8. Patients expected to have less than 3 months of reasonable health.
9. Patients who cannot shower and dress themselves.
10. Patients who are unable to walk without assistance, bedridden, non-ambulatory, confined to a wheel chair. Patients must be well enough to travel to the XYTOS Treatment Center.
11. Patients with low general vitality, major uncontrolled pain, poor appetite, jaundice, or severe abnormal bowel function: severe diarrhea or constipation.
12. Patients suffering from severe cachexia (wasting syndrome) or who are rapidly losing weight.
13. Patients with stints implanted for pancreatic cancer or bile duct cancer.
14. Patients with tumors involving a major blood vessel where treatment may lead to major hemorrhage. Adequate scans must be available to determine this criterion.
15. Patients whose tumors involve a major part of the vertebral column or the spinal cord, where destruction of the tumor could lead to collapse. Adequate scans must be available to determine this criterion.
16. Patients suffering from porphyria (a serious photosensitive, light sensitizing condition).

Patients who had surgery, chemotherapy or radiation therapy less than 3 weeks prior to XPDT.