Cylindrical Diode Detector
The ISORAD-3 is the only available cylindrical diode detector.
The ISORAD-3 cylindrical design
allows it to have nearly zero angular dependence along the axial axis, this makes it an ideal choice for
tangential treatment cases where it is difficult to predict angle of incidence. ISORAD-3 is 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 ≤ 1% for
measurements > 1 cGy.
ISORAD-3 diode detectors can be used in any situation where a surface mounted diode is needed to
verify patient dose.
ISORAD-3 diode detectors are particularly useful for tangential treatments where the angle of
incidence is difficult or impossible to predict.
ISORAD-3 diode detectors can be used in conjunction with some solid phantoms and the
IVD to verify complex treatment plans.
Energy Ranges - Choosing the Right ISORAD-3
ISORAD-3 detectors are offered in three photon energy ranges. A single energy compensated detector is
- P/N 1162000-0 1-4 MV
- P/N 1163000-0 6-12 MV
- P/N 1164000-0 15-25 MV
The ISORAD-3 offers exceptional accuracy.
When tested in air or in a cylindrical phantom for all the
- Variation in Axial response is only +/- 0.5% from 0º ~ 360º
When tested on top of 6 cm of solid or virtual water:
- Variation in Axial response is still only +/- 0.5% from -60º ~ 60º for 6 MV
- Variation in Axial response is only +/- 1.0% from -60º ~ 60º for 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. For 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 under normal stress loads, the
ISORAD-3 should be expected to last > 1,000,000 cGy.
ISORAD-3 construction is an advanced third-generation design.
Build-up consists of a material that is best suited for each energy range.
- ISORAD-3 is the only available diode with Cylindrical Symmetry
- Angular corrections are not required<
- Advanced n-type die design is accurate
- Compatibility with any diode based dosimetry system
- Very good reproducibility (≤ 1% for measurements >1 cGy)
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