title: Novel paint design based on nanopowder to protection against X and gamma rays.
abstract: BACKGROUND
  Lead-based shields are the standard method of intraoperative radiation protection in the radiology and nuclear medicine department. Human lead toxicity is well documented. The lead used is heavy, lacks durability, is difficult to launder, and its disposal is associated with environmental hazards. The aim of this study was to design a lead free paint for protection against X and gamma rays.
  
  
  METHODS
  In this pilot st we evaluated several types of nano metal powder that seemed to have good absorption. The Monte Carlo code, MCNP4C, was used to model the attenuation of X-ray photons in paints with different designs. Experimental measurements were carried out to assess the attenuation properties of each paint design.
  
  
  RESULTS
  Among the different nano metal powder, nano tungsten trioxide and nano tin dioxide were the two most appropriate candidates for making paint in diagnostic photon energy range. Nano tungsten trioxide (15%) and nano tin dioxide (85%) provided the best protection in both simulation and experiments. After this step, attempts were made to produce appropriate nano tungsten trioxide-nano tin dioxide paints. The density of this nano tungsten trioxide-nano tin dioxide paint was 4.2 g/cm(3). The MCNP simulation and experimental measurements for HVL (Half-Value Layer) values of this shield at 100 kVp were 0.25 and 0.23 mm, respectively.
  
  
  CONCLUSIONS
  The results showed the cost-effective lead-free paint can be a great power in absorbing the X-rays and gamma rays and it can be used instead of lead.
authors.affiliation: Department of Medical Physics and Biomedical Engineering, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Mohammad Mehdi
authors.initials: MM
authors.lastname: Movahedi
authors.affiliation: Department of Ergonomics, School of Health, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Adibe
authors.initials: A
authors.lastname: Abdi
authors.affiliation: Department of Medical Physics and Biomedical Engineering, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Alireza
authors.initials: A
authors.lastname: Mehdizadeh
authors.affiliation: Occupational Medicine Research Center, Iran University of Medical Science, Tehran, Iran.
authors.forename: Naser
authors.initials: N
authors.lastname: Dehghan
authors.affiliation: Medical Student, School of Medicine, Shiraz University of Medical Science, Shiraz, Iran.
authors.forename: Emad
authors.initials: E
authors.lastname: Heidari
authors.affiliation: Department of Maxillofacial Radiology, School of Dentistry, Shahid Sadougi University of Medical Science, Yazd, Iran.
authors.forename: Yusef
authors.initials: Y
authors.lastname: Masumi
authors.affiliation: Department of Occupational Health Engineering, Tehran University of Medical Science, Tehran, Iran.
authors.forename: Mojtaba
authors.initials: M
authors.lastname: Abbaszadeh
keywords: Lead-free shields; X and gamma rays; nano metal powder; nanopowder; new radiation shields; radiation protection