Quality assurance of proton beams using a multilayer ionization chamber system

Dhanesar, S; Sahoo, Narayan; Kerr, M.; Taylor, M.; Summers, P.; Zhu, Xiaorong Ronald; Poenisch, Falk; Gillin, Michael

doi:10.1118/1.4817481

Cited by 48 publications

(54 citation statements)

References 26 publications

(19 reference statements)

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“…The Zebra device (IBA Dosimetry) is a commercial MLIC designed to measure depth‐dose curves under broad field conditions (10) . It consists of a stack of 180 independent air‐vented, plane‐parallel ionization chambers fabricated with printed circuit board (PCB) technologies (see Fig.…”

Section: Methodsmentioning

confidence: 99%

“…Note that a

10 \times 10 {cm}^{2}

reference field also matches the optimum irradiation conditions of the Zebra (10) . Fields are delivered in a standalone mode, as described for the Giraffe measurements above.…”

Section: Methodsmentioning

confidence: 99%

“…As an alternative to above scanning water phantom measurements, multilayer ionization chambers (MLIC) can speed up data acquisition of depth‐dose curves of clinical particle beams. This has been demonstrated in the past 7 , 8 , 9 , 10 . Consequently, we evaluate if a large electrode MLIC (brand name ‘Giraffe’, IBA Dosimetry) can replace the combination of an integral chamber and scanning water phantom.…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of detectors for acquisition of pristine depth‐dose curves in pencil beam scanning

Bäumer

Koska

Lambert

et al. 2015

J Applied Clin Med Phys

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Acquisition of quasi‐monoenergetic ("pristine") depth‐dose curves is an essential task in the frame of commissioning and quality assurance of a proton therapy treatment head. For pencil beam scanning delivery modes this is often accomplished by measuring the integral ionization in a plane perpendicular to the axis of an unscanned beam. We focus on the evaluation of three integral detectors: two of them are plane‐parallel ionization chambers with an effective radius of 4.1 cm and 6.0 cm, respectively, mounted in a scanning water phantom. The third integral detector is a 6.0 cm radius multilayer ionization chamber. The experimental results are compared with the corresponding measurements under broad field conditions, which are performed with a small radius plane‐parallel chamber and a small radius multilayer ionization chamber. We study how a measured depth‐dose curve of a pristine proton field depends on the detection device, by evaluating the shape of the depth‐dose curve, the relative charge collection efficiency, and intercomparing measured ranges. Our results show that increasing the radius of an integral chamber from 4.1 cm to 6.0 cm increases the collection efficiency by 0%–3.5% depending on beam energy and depth. Ranges can be determined by the large electrode multilayer ionization chamber with a typical uncertainty of 0.4 mm on a routine basis. The large electrode multilayer ionization chamber exhibits a small distortion in the Bragg Peak region. This prohibits its use for acquisition of base data, but is tolerable for quality assurance. The good range accuracy and the peak distortion are characteristics of the multilayer ionization chamber design, as shown by the direct comparison with the small electrode counterpart.PACS number: 87.55.Qr

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Section: Methodsmentioning

confidence: 99%

“…Note that a

10 \times 10 {cm}^{2}

reference field also matches the optimum irradiation conditions of the Zebra (10) . Fields are delivered in a standalone mode, as described for the Giraffe measurements above.…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Evaluation of detectors for acquisition of pristine depth‐dose curves in pencil beam scanning

Bäumer

Koska

Lambert

et al. 2015

J Applied Clin Med Phys

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show abstract

“…Range and SOBP measurements can be accurately done in a single measurement with a stack of scintillating plates, such as the

28 \times 3 mm

thick plastic scintillators presented by Amaldi et al (1) or using a Zebra (IBA Dosimetry, Schwarzenbruck, Germany), a commercial multilayer ionization chamber (2) . It is also possible to measure the output with a single measurement using an ionization chamber in a solid phantom, or the collinearity of the proton beam axis and X‐ray beam axis using a film or ionization chamber array.…”

Section: Introductionmentioning

confidence: 99%

Daily QA in proton therapy using a single commercially available detector

Lambert

Bäumer

Koska

et al. 2014

J Applied Clin Med Phys

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We present here a novel method for using a single device in the daily quality assurance (QA) of pencil beam scanning (PBS) proton beams and an improved method for uniform scanning (US). The device can be used to measure the spot position, spot sigma, range, output, collinearity of the X‐ray system and proton beam, and to QA the first scatterers and a number of other imaging and mechanical checks. We have performed the daily QA according to this procedure for more than six months in both a PBS gantry and a US gantry. All of the tests were found to be sensitive and accurate enough to determine if the property being tested is within the tolerance. The output has remained within the ±.15em2% tolerance, with the majority of measurements within ±.15em1%, and the range was within ±.15em0.5.15emmm. The collinearity of the proton beam in both gantries is within the ±.15em1.15emmm tolerance in both X and Y directions for all measurements. A novel procedure to measure the functionality of the first scatterers in the US gantry is included in the QA procedure. It was found to be sensitive enough to pick up the thinnest scatterer of 0.6 mm in both possible failure methods — when it always remains in the beam or in the case when it never goes into the beam. The daily QA procedure presented here can be implemented at PBS or US proton therapy centers with a minimal outlay for equipment and setup time. The procedure can be performed in less than 30 min, and has been found to be accurate and reliable enough for the QA of a proton therapy gantry before patient treatment every day.PACS number: 87.55.Qr

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“…The central-axis depth dose distribution in case (c) was measured by a multi-layer ionization chamber (MLIC, IBA Dosimetry GmbH, Germany) [22]. The 2D dose distributions at specific depths were measured with a 2D ion chamber array (MatriXX PT, IBA Dosimetry GmbH, Germany) [23].…”

Section: Measurementsmentioning

confidence: 99%

Inter-comparison of Dose Distributions Calculated by FLUKA, GEANT4, MCNP, and PHITS for Proton Therapy

et al. 2017

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Abstract. The dose distributions from proton pencil beam scanning were calculated by FLUKA, GEANT4, MCNP, and PHITS, in order to investigate their applicability in proton radiotherapy. The first studied case was the integrated depth dose curves (IDDCs), respectively from a 100 and a 226-MeV proton pencil beam impinging a water phantom. The calculated IDDCs agree with each other as long as each code employs 75 eV for the ionization potential of water. The second case considered a similar condition of the first case but with proton energies in a Gaussian distribution. The comparison to the measurement indicates the inter-code differences might not only due to different stopping power but also the nuclear physics models. How the physics parameter setting affect the computation time was also discussed. In the third case, the applicability of each code for pencil beam scanning was confirmed by delivering a uniform volumetric dose distribution based on the treatment plan, and the results showed general agreement between each codes, the treatment plan, and the measurement, except that some deviations were found in the penumbra region. This study has demonstrated that the selected codes are all capable of performing dose calculations for therapeutic scanning proton beams with proper physics settings.

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Quality assurance of proton beams using a multilayer ionization chamber system

Cited by 48 publications

References 26 publications

Evaluation of detectors for acquisition of pristine depth‐dose curves in pencil beam scanning

Evaluation of detectors for acquisition of pristine depth‐dose curves in pencil beam scanning

Daily QA in proton therapy using a single commercially available detector

Inter-comparison of Dose Distributions Calculated by FLUKA, GEANT4, MCNP, and PHITS for Proton Therapy

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