FAQs

How can I learn more about film dosimetry?

Read An Introduction to DoseLab Pro, which is the first chapter in DoseLab Pro’s user manual.

What are film’s advantages and drawbacks for patient-specific IMRT/SBRT/IMAT QA?

Film has excellent spatial resolution, has a dose response independent of incident beam angle and beam energy (EDR2 and EBT2 films), and a low startup cost. The high spatial resolution and accurate dosimetry make it an excellent choice for commissioning IMRT/IMAT systems, as the additive effects of MLC penumbra modeling can be compared to treatment planning system calculations very clearly. Film is well-suited for patient-specific verifications for the same reasons, although film calibration, processing, and scanning can add to the time required. Using self-processing EBT2 film and DoseLab Pro’s fast dynamic wedge calibration technique can minimize the measurement time, allowing busy clinics to reap the benefits of film dosimetry without the added workload.

How often should I calibrate film?

There is no one correct answer. For the highest levels of accuracy, a calibration may be performed at every measurement session. However, most clinics find that calibrating one film per batch provides high quality results. It is recommended that each clinic determine the accuracy of using one calibration per batch for their conditions (type of film, storage environment, processor, etc.). It is generally not recommended to use a calibration from a different batch of film, or to not calibrate film, when performing patient-specific QA.

Which film scanner should I use?

Both Vidar and Epson make scanners that perform well for radiation oncology clinics. Vidar scanners have more range for films darker than 2.0 OD, but are significantly more expensive. The Epson Expression 10000XL-PH (with transparency adapter) is an excellent choice for both radiochromic and radiographic films. Both scanners perform better when their output is corrected by a dosimetry program such as DoseLab Pro. Mobius Medical Systems, LP has no financial ties to scanner manufacturers.

Which type of film should I use?

Both Kodak EDR2 and Gafchromic EBT2 films perform well for radiation oncology clinics. EBT2 film is more expensive per sheet, but does not require a film processor. Generally EBT2 film is recommended for new clinics who use less than 300 pieces of film per year. Mobius Medical Systems, LP is not affiliated with film manufacturers.

I use Sun Nuclear’s MapCHECK™ or iba’s MatriXX for IMRT QA. What extra features does DoseLab Pro offer?

DoseLab Pro generally has most features the software included with your measurement device has, but expands its functionality to include the following:

• Automatic dose comparisons with batch mode (8 seconds per measurement) saves time
• Automatic PDF report generation
• Automatic alignment with comparison to expected position (currently MapCHECK only)
• PQI Analytics for advanced trend reporting and outlier detection
• More dose comparison options, such as 2D dose/DTA histograms and NAT calculations
• Advanced normalization options based on regions, points, or gamma pass rates
• TG-142 complaint monthly and annual test routines (starshot, MLC strip tests, Winston-Lutz, etc.)
• MV, kV, CT, and CBCT Imaging QA

We recognize that not every clinic with a measurement array needs these advanced dose comparison features, so we offer our linac performance and imaging QA tools separately in DoseLab TG-142, with the option to upgrade to DoseLab Pro for film dosimetry and dose comparisons at any time.

How does using DoseLab Pro with a MapCHECK™, MatriXX, or similar dosimeter change the clinical workflow?

The measurement is performed using the diode or ion chamber array’s included software. The results are saved to a file, and DoseLab Pro automatically loads your measurements as soon as your calculated files are selected. Files can then be analyzed in a fully automatic batch mode, producing PDF reports in about 5 seconds per comparison.

When are film measurements mandatory?

When accurate, high resolution results are needed. This includes commissioning tests of a new linac, new MLC, new TPS, or new modality (IMAT, for example). After it is determined the system is commissioned correctly, a lower resolution device can be used for routine patient-specific QA. Film is also required for starshot tests. Winston-Lutz, flatness and symmetry, light/radiation field coincidence, and MLC strip tests can be measured with film or EPID.

Can I use MapCHECK™ or MatriXX as my primary QA device, and film as a backup QA device for difficult comparisons or monthly tests?

Yes. For example, a clinic may choose to use a MapCHECK™ to perform patient-specific QA, but expose an IMRT film each month as a high-resolution check. DoseLab Pro’s built-in fast film calibration and support for a wide range of dosimeters make it easy for clinics to choose different dosimeters for different tasks, allowing 2D arrays to be used for daily measurements and film to be used for monthly / occasional tests.

Can I switch dosimeters in the future and still use DoseLab Pro for dose comparisons and PQI Analytics?

Yes. DoseLab Pro is designed to be a processing and storage hub for all 2D dose comparisons, no matter how they are measured. This allows physicists to learn only one software package to perform dose comparisons and TG-142 compliant 2D tests using a variety of measurement devices.

Can I add a custom imaging phantom in DoseLab Pro?

Yes. DoseLab Pro’s Imaging QA suite automatically analyzes reference images. Thus, to add a custom imaging phantom or Catphan module, users can save a reference image of the phantom in DoseLab Pro’s “Reference images” folder. The Imaging QA preferences can then be edited to specify the regions of interest to analyze. All automation options work with custom phantoms. DoseLab Pro has built-in support for most common imaging phantoms used in radiation oncology, so most users will not need to add any additional imaging QA phantoms.

Does DoseLab Pro automatically analyze low contrast regions?

Not specifically. Instead, DoseLab Pro calculates the contrast to noise ratio (CNR) of an image. Many phantoms include sections that have small circular areas with little contrast from their surroundings. Typically, physicists look at these areas to determine the smallest area that can be detected for a given contrast level. This is an excellent demonstration of the clinical application of CNR, but is not well-suited for quantitative calculations. DoseLab Pro determines a single CNR value of an image, which can then be tracked for each QA session.

Why does DoseLab Pro focus on automated processes?

Automating routine processes, such as dose comparisons, Winston-Lutz tests, starshot analysis, etc. produces rapid results that are highly accurate and reproducible. DoseLab Pro’s automation greatly simplifies the number of parameters that must be specified (typically 0-2 are needed, and initial values are automatically calculated) and includes advanced image processing routines so that its automation works with every clinic’s images. All image processing results are displayed visually, so physicists can be confident that the generated data is accurate. All dose comparison automation routines can easily be turned on or off via DoseLab Pro’s Automation menu.

What are DoseLab Pro’s advantages as a 2D dosimetry comparison and linac QA system?

DoseLab Pro was designed from the ground up to be fast, simple, and powerful. Every step of the QA process is incorporated into DoseLab Pro’s workflow, including scanner uniformity corrections, file transfers, film calibrations, measurement alignment, and positioning. Its unique comparison preferences allows physicists to define a QA phantom and measurement geometry once, then perform a variety of comparisons by selecting different groups of settings. Its single image analysis and image processing routines are designed to be easy to use, requiring only one or two parameters to be adjusted, yet very flexible and robust. PQI Analytics allows users to explore patient-specific results, and gives physicists the tools required to set clinical IMRT QA criteria.

Our feature list has more detailed information.

Which QA phantoms are supported by DoseLab Pro?

Nearly all. DoseLab Pro is designed to be extremely flexible in defining phantoms. It requires two points to determine film rotation, and optionally can calculate the shift from expected position if the phantom has a fiducial or uses fixed-size and location film.

Does DoseLab Pro support EPID images?

Yes. EPID images are excellent for non-dosimetric measurements, such as Winston-Lutz and MLC strip test films. New models of EPIDs have pixel sizes of approximately 0.5 mm at isocenter. DoseLab Pro does not support converting EPID images to dose images (generally used for IMRT QA purposes). An external program, such as Sun Nuclear’s EPIDose or Varian’s Portal Dosimetry, must first be used to convert the images to dose. Afterwards, automatic batch analysis of the converted files can be performed in DoseLab Pro.

How many computers can I install DoseLab Pro on?

As many as you’d like. DoseLab Pro’s license allows users to install software on multiple physicist/dosimetrist/physician computers, or even install on a shared drive for easy access throughout their department. Site licenses allow the software to be installed on any computer located at the treatment site, and be used to perform QA on any linear accelerator located on-site.

What training is included with DoseLab Pro?

After a license for DoseLab Pro is purchased, users can receive training and configuration assistance via phone and web support sessions. Additionally, we have an extensive collection of training videos. These videos cover every aspect of DoseLab Pro’s operation in detail, and provide an excellent supplement to DoseLab Pro’s 330 page manual.

What are the differences between the original open-source DoseLab and DoseLab Pro?

• DoseLab Pro supports Windows Vista and Windows 7, in addition to Windows XP
• DoseLab Pro has dozens of new features, including PDF reports, imaging QA, automatic comparisons, interactive dose normalization, MLC strip tests, Winston-Lutz tests, film calibration profile generation, etc.
• DoseLab Pro has dozens of improved features, including gamma calculations, film calibration, uniformity corrections, starshot analysis, Windows file transfers, flatness and symmetry, etc.
• DoseLab Pro has hundreds of bug fixes and increases the speed of dozens of tools
• DoseLab Pro has improved DICOM image importing
• DoseLab Pro has hundreds of stability improvements. However, no severe anomalies were found in the open-source DoseLab’s core comparison calculations.
• DoseLab Pro’s user manual has been significantly expanded
• DoseLab Pro offers full telephone, email, remote computer, and HD training video support

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