BACKGROUND AND PURPOSE A comprehensive dosimetry intercomparison has been carried out involving all the radiotherapy centres, all external beam modalities and every radiotherapy treatment unit in the Republic of Ireland. MATERIALS AND METHODS Reference point measurements were made for all megavoltage photon beams. Doses were also investigated in planned three-field distributions. One of these...

We report a method for characterizing the focussing laser beam exiting the objective in a laser scanning microscope. This method provides the size of the optical focus, the divergence of the beam, the ellipticity and the astigmatism. We use a microscopic-scale knife edge in the form of a simple transmission electron microscopy grid attached to a glass microscope slide, and a light-collecting op...

Objective. To evaluate the treatment outcome and prognostic factors in patients with sinonasal malignant tumors invading skull base. Study Design and Setting. A retrospective clinical study at the Yamagata University School of Medicine. Subjects and Methods. Three patients with sinonasal malignant tumors invading skull base were presented in present study. All patients were treated with carbon ...

Onboard cone-beam CT (CBCT) has been widely used in image guided radiation therapy. However, the longitudinal coverage is only 15.5 cm in the pelvis scan mode. As a result, a single CBCT scan cannot cover the planning target volume in the longitudinal direction for over 80% of the patients. The common approach is to use double- or multiple-circular scans and then combine multiple CBCT volumes a...

BACKGROUND The combination of external-beam radiotherapy and brachytherapy is used commonly to treat men with prostate cancer. In this analysis, the authors examined the rate of biochemical recurrence (BR) and late grade > or =3 genitourinary (GU) and gastrointestinal (GI) toxicity after treatment with external-beam radiotherapy and brachytherapy in a multiinstitutional, cooperative group setti...

The Linac Coherent Light Source (LCLS) is a SASE 1.5-15 Å x-ray Free-Electron Laser (FEL) facility under construction at SLAC [1], and presently in an advanced phase of commissioning. The injector, linac, and new bunch compressors were commissioned in 2007 [2] and 2008 [3], establishing the necessary electron beam brightness at 14 GeV. The final phase of commissioning, including the FEL undulat...

PURPOSE Cone beam CT (CBCT) in image-guided radiotherapy (IGRT) offers a tremendous advantage for treatment guidance. The associated imaging dose is a clinical concern. One unique feature of CBCT-based IGRT is that the same patient is repeatedly scanned during a treatment course, and the contents of CBCT images at different fractions are similar. The authors propose a progressive dose control (...

PURPOSE To report on outcomes after proton beam radiotherapy of choroidal melanoma using a 62-MeV cyclotron in patients considered unsuitable for other forms of conservative therapy. METHODS AND MATERIALS A total of 349 patients with choroidal melanoma referred to the Liverpool Ocular Oncology Centre underwent proton beam radiotherapy at Clatterbridge Centre for Oncology (CCO) between January...

AIMS AND BACKGROUND To evaluate the impact of preoperative chemoradiation on sphincter preservation in patients with low-medium locally advanced resectable rectal cancer treated by four chemoradiation schedules. MATERIALS AND METHODS Between 1990 and 2002, 247 patients were treated according to four schedules of chemoradiotherapy: FUMIR (5-fluorouracil, mitomycin, external beam radiotherapy 3...

background: in order to deliver the precise dose to the target in radiotherapy, absorbed dose to water at the reference point should be assessed. when the calibration procedure is performed for a reference dosimeter in the 60co beam of a secondary standard dosimetry laboratory (ssdl), the total uncertainty in absorbed dose to water (dw) is estimated to be approximately 1.5%. this study attempts...