What is Pulse Normalization?
Linear accelerators (linacs) used in radiotherapy do not emit radiation continuously – they operate through discrete pulses, typically between 100 and 400 pulses per second. Each pulse has a duration of just a few microseconds.
Most water tank dosimetry systems operate with electrometers that have time constants in the order of milliseconds. This means they cannot capture individual pulses, instead performing an averaged measurement over time.
The SunSCAN 3D from Sun Nuclear revolutionizes this approach with its Pulse Normalization technology.
The Ultra-Fast Electrometer Advantage
The SunSCAN 3D electrometer features a time constant of just 1 microsecond – the fastest response available in the water tank dosimetry market.
This exceptional speed enables:
- Capturing and measuring all individual pulses from the linear accelerator
- Eliminating sampling artifacts that affect other systems
- Obtaining dose data truly representative of beam delivery
Impact on Small Field Dosimetry
Small field dosimetry is particularly challenging due to:
- Loss of lateral electronic equilibrium
- Partial occlusion of the radiation source
- High variability between detectors
- Positioning sensitivity
Traditionally, precise measurement in small fields requires the use of a reference detector alongside the field detector, increasing complexity and setup time.
The SunSCAN 3D Solution
Thanks to Pulse Normalization technology, the SunSCAN 3D produces more accurate results than any other water tank for small field dosimetry, using only a single detector.
This translates to:
- Simpler setup – no need to mount and align a reference detector
- Faster measurements – less preparation and verification time
- More consistent results – elimination of additional variables
- Lower uncertainty – data directly from the detector of interest
Clinical Applications
This technology is particularly relevant for:
- SRS (Stereotactic Radiosurgery) – fields typically between 4-20mm
- SBRT (Stereotactic Body Radiotherapy) – small high-dose fields
- IMRT/VMAT – small field segments during dynamic delivery
- MLC Commissioning – characterization of individual leaf fields
Conclusion
The Pulse Normalization of the SunSCAN 3D represents a significant advancement in water tank technology for dosimetry. The ability to measure individual linac pulses, combined with the elimination of the need for a reference detector in small fields, makes this system the superior choice for departments demanding maximum precision in their dosimetric measurements.
To learn more about the SunSCAN 3D and its unique capabilities, visit our product page or contact the Interphysix team.
Learn more: View SunSCAN 3D product
Última actualização: 13/02/2026