BACKGROUND/AIMS A major drawback of laser endoscopy in the palliation of malignant dysphagia is the need for repeated treatments. This study was designed to test whether external beam radiotherapy would reduce the necessity for repeated laser therapy. PATIENTS/METHODS Sixty seven patients with inoperable oesophageal or gastric cardia cancers and satisfactory swallowing after initial laser rec...

OBJECTIVE To determine whether the more intensive screening and treatment for prostate cancer in the Seattle-Puget Sound area in 1987-90 led to lower mortality from prostate cancer than in Connecticut. DESIGN Natural experiment comparing two fixed cohorts from 1987 to 1997. SETTING Seattle-Puget Sound and Connecticut surveillance, epidemiology, and end results areas. PARTICIPANTS Populati...

The treatment of clinically locally advanced prostate carcinoma (stage cT3) remains controversial. One of the main reasons for this controversy results from the substantial staging error attached to the clinical diagnosis cT3 with overstaged T2 tumors and understaged node-positive cases. Treatment options in this situation include radical prostatectomy, external beam radiotherapy, immediate or ...

External radiation beam treatment of cancer tumours involves delivery of invisible radiation beams through the body where internal structures can not be seen. Beam targeting of patient anatomy has to very accurate to achieve the desired therapeutic result. Good understanding of radiotherapy treatment (RT) concepts is essential to training. This paper presents a virtual environment simulator dev...

We consider topology based criteria for the selection of optimal beam orientations for conformal external radiotherapy. The advantage of such an approach is that computation time is considerably reduced since no dose calculation is required. The algorithm preclassifies all possible irradiation directions by assigning to each a fitness measure, the geometry fitness factor (GFF). This factor is a...