Isorad-3™
Cylindrical Diode Detectors
The ISORAD-3™ is the only available cylindrical diode detector. The ISORAD-3™'s cylindrical design allows it to have nearly zero angular dependence along the axial axis, making it an ideal choice for tangential treatment cases where it is difficult to predict angle of incidence. ISORAD-3™'s are available in three photon energy ranges. Each energy range uses a different buildup material designed to give a reading at dmax, therefore no additional buildup is required. ISORAD-3™ reproducibility error is less than 0.5% for measurements greater than 1cGy.
The ISORAD-3™ diode detectors are an advanced third-generation design that can be used in any situation where a surface-mounted diode is needed to verify patient dose. They are particularly useful for tangential treatments where the angle of incidence is difficult or impossible to predict. These diodes can also be used in conjunction with solid phantoms to verify complex treatment plans. The detectors are not waterproof as they are designed for patient dose detection.
The ISORAD-3™ offers exceptional accuracy. When tested in air or in a cylindrical phantom for all the beams, the variation in Axial response is only ±1.0% from 0° ∼ 360°. When tested on top of a 6cm piece of Solid or Virtual Water, variation is still only ±1.0% from -60° ∼ 60° for 6 MV and 18 MV.
As with any diode, ISORAD-3™ sensitivity will gradually change over time. This rate of change will depend on the energies used and the frequency of use. With normal use, plan on re-calibration once per year. Note that ISORAD-3™ life expectancy is not limited by radiation exposure; in fact, the more an ISORAD-3™ is used the less its response characteristics will change. Life expectancy is an issue of proper handling and care. Broken coaxial connectors and cables are the most common cause of failure. When handled properly, the ISORAD-3™ should be expected to last greater than 1,000,000cGy accumulated dose.