OCTAVIUS® Detector 1600 SRS

Detector array for patient plan verification and quality control of SRS applications

  • Detector array with 1521 liquid-filled ionization chambers
  • Filmless patient plan verification and machine-specific QA
  • Suitable for use with OCTAVIUS 4D system - the modular phantom for IMRT, VMAT and SRS/SBRT
  • Verification of single-isocenter treatments of multiple metastasis
  • Active volume 2.5 x 2.5 x 0.5 mm³
  • Detector spacing in center area: 2.5 mm
  • Best available field coverage for SRS applications with a field size of 15 x 15 cm²
  • Effective tool for CyberKnife QA

Best available field coverage for SRS applications

Multiple brain metastases:
Gold standard ionization chambers:
Solution for Cyberknife:
Largest SRS detector array with a well-established system:
High spatial resolution:
Suitable for the OCTAVIUS 4D phantom:
Multiple brain metastases:

Verification of single isocenter SRS for multiple brain metastases - one system suitable for QA of IMRT, VMAT and SRS/SBRT

Gold standard ionization chambers:
  • Long lifetime
  • Stable and reliable signal independent from accumulated dose
  • No on-site recalibration
  • Good field coverage
  • Nearly water-equivalent
Solution for Cyberknife:

A well-established solution for CyberKnife QA:

  • Use the optional accessory package for CyberKnife patient QA
  • Learn more about the QA workflow under Related Downloads
Largest SRS detector array with a well-established system:

Perfect field size for Single-Isocenter Multiple-Target Plans

  • Only one measurement for all PTVs: a time saving workflow
  • Coverage of all clinical relevant regions
High spatial resolution:

2,5 mm center to center

Suitable for the OCTAVIUS 4D phantom:
  • true 3D dose measurements for SRS/SBRT; patient specific QA for multiple targets in different planes in one measurement

Unique Properties - Optimal for SRS Treatments

OCTAVIUS® Detector 1600 SRS -
Unique Detector Properties


  • Advancement of well-established OCTAVIUS® Detector 1000 SRS
    with > 50% more chambers
  • 1521 liquid-filled ionization chambers with an active volume
    of 2.5 x 2.5 x 0.5 mm³ (0.003 cm³)
  • Enlarged active detector area with 15 x 15 cm²
  • 729 ionization chambers in enlarged high-resolution inner area
    of 6.5 x 6.5 cm²
  • Spatial resolution 2.5 mm in inner area
  • For filmless patient plan verification and machine specific QA
  • Excellent error detection for all stereotactic treatment plans

OCTAVIUS® 4D with 1600 SRS + Top SRS plus (Ø 21 cm)

Patient specific phantom adaptation

For measurements with OCTAVIUS 4D the OCTAVIUS Detector 1600 SRS can be used with the OCTAVIUS Top SRS plus. With a diameter of 21 cm the resulting homogeneous cylinder geometry adapts the anatomy of a human head perfectly in SRS treatments of the brain.

In addition, for either SBRT procedures (e.g. stereotactic treatment of lung metastases) or other clinical entities the OCTAVIUS Detector 1600 SRS can be combined with the 32 cm OCTAVIUS Top Standard, emphasizing its multifunctional nature.

Similar geometry of phantom and patient anatomy

Optimal size for multi target SRS treatments

Stereotactic treatments require high radiological and, most importantly, spatial precision which should be checked for each patient individually.
Besides 2D patient plan verification OCTAVIUS Detector 1600 SRS allows independent 3D patient plan verification when combined with OCTAVIUS 4D. Due to its high spatial resolution (2.5 mm) and its large detector area of 15 x 15 cm² OCTAVIUS 1600 SRS allows patient specific QA of SRS treatments, especially of those including multiple, widely spaced target volumes even in different planes (e.g. multiple metastases in stereotactic brain applications).

  • 3D verification of multiple, widely-spaced target volumes within a single measurement >> No repeated and time-consuming measurements of individual/grouped target volumes requiring couch/detector shifts
  • Only 3D patient specific QA guarantees perfect coverage of multiple target volumes in different planes within a single measurement.
  • Calculation of 3D volume gamma metrics

Recently TPS and Linac manufacturers introduced new solutions
for efficient planning of SRS treatments of multiple target
volumes with a single isocenter (e.g. Varian HyperArc and
Brainlab Elements® Multiple Brain Mets SRS). These applications
often include multiple widely-spaced target volumes easily
covered with the large detector area of 15 x 15 cm².
In combination with OCTAVIUS 4D even multiple target volumes
in different planes can be detected within one measurement.

Commissioning of SRS/SBRT techniques

PTW OCTAVIUS Detectors have proven to be accurate tools for planar dose measurements.

Especially for radiotherapy departments implementing SRS/SBRT delivery techniques into their clinical practice, OCTAVIUS 1600 SRS can support and facilitate the commissioning process.

VeriSoft takes arbitrary couch angles into account

True verification of non-coplanar SRS treatments

Conventional SRS treatments and especially modern single isocenter SRS treatments, such as Varian HyperArcTM or Brainlab Elements® Multiple Brain Mets SRS, use a mixture of coplanar and non-coplanar beams improving the dose conformity.

Together with OCTAVIUS 4D the new OCTAVIUS Detector 1600 SRS represents an ideal tool for true 3D verification of SRS treatments with non-coplanar beams.

  • True & simple 3D verification of SRS deliveries with non-coplanar beams – verification of the real patient plan with couch angles collapsed to 0°
  • Arbitrary couch angles up to 90°/270° supported - no limitations of couch angles with respect to beam quality

Our verification software VeriSoft offers multiple special tools to analyze patient specific QA


  • The CyberKnife is a high precision robotic radiosurgery device for stereotactic treatments. Because of the small target volumes and the high doses, it is important that the system guarantees high accuracy.
    • The negligible angular dependence of the OCTAVIUS Detector 1600 SRS makes it to an efficient tool for CyberKnife QA.
    • The high resolution detector and the CyberKnife marker plate guarantee a fast and user-friendly workflow for patient-specific QA.
    • Suitable for machine QA as the Iris QA or the Laser and Radiation coincidence check.

To learn mor about time-saving and realiable measurements with the OD 1600 SRS at the CyberKnife, read our brochure.


Type of product: Two-dimensional array with 1521 liquid-filled ionization chambers
Application: IMRT patient plan verification (include VMAT)
Machine-specific QA
Online beam adjustment
Measuring quantities: Absorbed rate and absorbed dose
Range of use: (0.1 ... 24) Gy/min
Resolution: 0.1 mGy, 0.1 Gy/min
Dead time: Zero
Display cycle: (100 ... 800) ms
Type of detectors: Plane-parallel, liquid-filled ionization chambers
Detector layout: Center area (6.5 cm x 6.5 cm): spacing 2.5 mm
Outer area (15 cm x 15 cm): spacing 5 mm
Nominal response: 16 nC/Gy
Size of detectors: 2.5 mm x 2.5 mm x 0.5 mm (0.003 cm³)
Active detector area: 15 cm x 15 cm
Outer dimensions: 300 mm x 467 mm x 22 mm (W x D x H)
Weight: 5.9 kg
Design Motorized, modular phantom, consisting of base unit with four exchangeable tops    
Dimensions: Phantom diameter 320 mm, length 343 mm    
Weight: Base unit 20,7 kg    
Angle range ± 360°    
Material: Polystyrene    
Density: 1.05 g/cm³    
Top standard: Phantom diameter 320 mm
weight 8.9 kg
Top SRS: Phantom diameter 170 mm
weight 2.3 kg
Top SRS plus: Phantom Diameter 210 mm
weight 3.7 kg
Top Linac QA: 50 mm water-equivalent build-up
weight 2.2 kg

Related Downloads

OCTAVIUS Detector 1600 SRS 3D Patient QA ( 4 MB )
OCTAVIUS Detector 1600 SRS at Cyberknife ( 2 MB )
Solutions for Small Field Applications ( 5 MB )
Radiation Medicine Catalog ( 9 MB )

Related Literature

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