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Compliance with custom trays was poor in this series. Specific postirradiation dental care follow-up visits and education have demonstrated their utility in the era of 2D irradiation. We currently advocate an 18-month compliance with custom trays in IMRT patients on the basis of the Parsport trial, after which we assess the quality of salivary recovery before recommending prolonged use or interruption. Data with innovative irradiation techniques are however required.

PURPOSE: Imaging phantoms can be cost prohibitive, therefore a need exists to produce low cost alternatives which are fit for purpose. This paper describes the development and validation of a low cost paediatric pelvis phantom based on the anatomy of a 5-year-old child. METHODS: Tissue equivalent materials representing paediatric bone (Plaster of Paris; PoP) and soft tissue (Poly methyl methacrylate; PMMA) were used. PMMA was machined to match the bony anatomy identified from a CT scan of a 5-year-old child and cavities were created for infusing the PoP. Phantom validation comprised physical and visual measures. Physical included CT density comparison between a CT scan of a 5-year old child and the phantom and Signal to Noise Ratio (SNR) comparative analysis of anteroposterior phantom X-ray images against a commercial anthropomorphic phantom. Visual analysis using a psychometric image quality scale (face validity). RESULTS: CT density, the percentage difference between cortical bone, soft tissue and their equivalent tissue substitutes were-4.7 to-4.1% and-23.4%, respectively. For SNR, (mAs response) there was a strong positive correlation between the two phantoms (r>0.95 for all kVps). For kVp response, there was a strong positive correlation between 1 and 8 mAs (r=0.85), this then decreased as mAs increased (r=-0.21 at 20 mAs). Psychometric scale results produced a Cronbach's Alpha of almost 0.8. CONCLUSIONS: Physical and visual measures suggest our low-cost phantom has suitable anatomical characteristics for X-ray imaging. Our phantom could have utility in dose and image quality optimisation studies.

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