NE2528/3 Perspex Phantom for Therapy Beam QC


The NE2528/3 Water Phantom is a portable water phantom used in conjunction with a Farmer Ionization Chamber (2505/3) for routine consistency checks of therapy beam output.

This portable water phantom consists of a strong “Perspex” (Polymethyl methacrylate) box containing a transverse tubular sleeve into which the 0.6cc Farmer Ionization Chamber 2505/3 fits. The center of the chamber volume aligns exactly with the intersection point of reference lines engraved on the beam entrance side of the box. A small spring clip prevents the chamber moving during use. A removable screw plug in the base enables the box to be filled with water. Two expansion chambers are provided to enable it to be used over a wide range of ambient temperatures and pressures. The useful energy range is 150kV to 10MV.

The phantom should be placed in the treatment room several hours before the measurements to allow the water to reach room temperature. Simply position the phantom in the radiation beam and align the beam axis with the chamber center of volume with the help of the cross hairs engraved on the front. Then set the source skin distance SSD (or FSD) to the value used on the particular therapy machine (e.g. 100cm, 60cm) and the field dimensions to the size which has been chosen to be the reference value (e.g 10x10cm).

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