Surface dose measurements in therapeutic x-ray beams are of importance in determining the dose to the skin of patients undergoing radiotherapy. Measurements were performed in the 6-MV beam of a medical linear accelerator with LiF thermoluminescence dosimeters (TLD) using a solid water phantom. TLD chips (surface area 3.17 x 3.17 cm2) of three different thicknesses (0.230, 0.099, and 0.038 g/cm2) were used to extrapolate dose readings to an infinitesimally thin layer of LiF. This surface dose was measured for field sizes ranging from 1 x 1 cm2 to 40 x 40 cm2. The surface dose relative to maximum dose was found to be 10.0% for a field size of 5 x 5 cm2, 16.3% for 10 x 10 cm2, and 26.9% for 20 x 20 cm2. Using a 6-mm Perspex block tray in the beam increased the surface dose in these fields to 10.7%, 17.7%, and 34.2% respectively. Due to the small size of the TLD chips, TLD extrapolation is applicable also for intracavity and exit dose determinations. The technique used for in vivo dosimetry could provide clinicians information about the build up of dose up to 1-mm depth in addition to an extrapolated surface dose measurement.

The use of metal plates, designed to be screwed into the bone in reconstruction of composite mandibular defects is an accepted and widely used procedure in oral cancer therapy (Castillo et al, 1988; Sindet-Pedersen, 1988). Many of these patients must receive post-surgical radiotherapy in the course of their treatment because of possible residual microscopic disease. The effects of radiation on tissue-metal interfaces have been studied for photon (Dutreix & Bernard, 1966; Gibbs et al, 1976; Hudson et al, 1984) and electron beams (Weatherburn et al, 1975; Khan et al, 1976; Gagnon & Cundiff, 1980; Klevenhagen et al, 1982). They have been found to result in an enhancement of the dose to the tissue in the immediate vicinity of the interface on the side facing the beam. A search through the literature has revealed limited studies on the effects of radiation beams on metal mandibular implants of the oral cavity (Castillo et al, 1988; Scher et al, 1988). These investigations were confined to stainless steel and vitallium plates irradiated with 6 MV photons. In the last few years, titanium reconstruction plates have become available and are growing in popularity because of the increased strength relative to the thickness of the plate, greater tissue compatibility and easier adaptation to the bony fragments.

A retrospective review of 381 patients with histologically confirmed nasopharyngeal carcinoma referred from all regions of Saudi Arabia to the King Faisal Specialist Hospital and Research Centre during the 10½-year period (June 1975 to December 1985 demonstrated a high frequency of stage IV tumors (93%), with 17.3% having distant metastases at presentation. There was a very low incidence (2%) of keratinizing squamous cell carcinoma, considered due to the relatively young age of the population. Age analysis indicated a peak incidence among the referred cases in the 45-55 age group, with a smaller peak in the 20-24 age group for both males and females, although the younger age peaks were reduced when the patient numbers were standardized for available population census figures.

Letter to the Editor regarding meperidine prescriptions in Queensland, Australia, 1999 to 2010.

This report reviews various management options for treatment-induced neuropathic pain in breast cancer. First-line options include tricyclic antidepressants and anticonvulsant drugs. Opioids should be prescribed according to published guidelines. Second-line treatments include lignocaine, mexiletine and ketamine. Sympatholytic therapies are available to patients with features of chronic regional pain syndrome. Anti-inflammatory agents are used for neurogenic inflammation. Surgical interventions are considered for refractory neuropathic pain. Interdisciplinary management is appropriate when persisting pain causes physical and psychosocial disabilities.