Gel dosimetry for three dimensional proton range measurements in anthropomorphic geometries

Hillbrand, Martin; Landry, Guillaume; Ebert, S.; Dedes, G.; Pappas, E.; Kalaitzakis, Georgios; Kurz, Christopher; Würl, Matthias; Englbrecht, Franz Siegfried; Dietrich, Olaf; Makris, D.; Pappas, E.; Parodi, Katia

doi:10.1016/j.zemedi.2018.08.002

Cited by 24 publications

(25 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Four independent asymmetric spin echoes were acquired after each excitation at echo times of TE = 36, 436, 835, 1230 ms with a multicontrast half‐Fourier‐acquired single‐shot turbo‐spin‐echo (HASTE) sequence. For more details and other sequence parameters see Hillbrand et al 21 . The acquired multiecho image data were converted to quantitative

R_{2}

values (

R_{2} = 1 / T_{2},

transverse relaxation rate) in a postprocessing step 21,28,29 .…”

Section: Methodsmentioning

confidence: 99%

“…transverse relaxation rate) in a post-processing step 21,30,31 . The values are proportional to the delivered = 1/ 2 , 2 dose and therefore allow for range determination.…”

Section: Dose Readoutmentioning

confidence: 99%

“…A drawback of the presented method is that only one specific beam direction can be tested per gel cylinder or film piece. Although the used phantom allows for easy gel replacement in contrast to the previous phantom design used by Makris et al 26 and Hillbrand et al 21 , testing multiple beam direction still requires considerable effort even when the additional costs of separate gel cylinders per beam direction are neglected. While in this work the number of possible beam angles was limited due to the fixed orientation of the film holder, a TPS-based pre-study to evaluate the most relevant beam angle, e.g.…”

Section: Accepted Articlementioning

confidence: 99%

See 2 more Smart Citations

Measurement‐based range evaluation for quality assurance of CBCT‐based dose calculations in adaptive proton therapy

Neppl

Kurz

Köpl³

et al. 2021

Medical Physics

Self Cite

View full text Add to dashboard Cite

In online adaptive radiation therapy, in-room CBCT imaging data lacks the quality and accurate electron density information a planning X-ray computed tomography (CT) scan provides. Therefore, corrections of the in-room images must be performed to enable dose calculation and treatment adaptation. These procedures need to be Accepted ArticleThis article is protected by copyright. All rights reserved evaluated carefully. So far, evaluations are only based on recalculation of the initial treatment plan on the new image data and disregard effects of the optimization itself.This study aims to fill this gap by proposing a measurement and reoptimization based approach to analyze image data for online adaptive proton therapy, where inaccuracies in the planning image data have a much larger effect on dose calculation and optimization compared to photon therapy.The measured results of this study showed a high agreement with the expectations from recalculations and reoptimization based on the treatment planning system only.

show abstract

R_{2}

values (

R_{2} = 1 / T_{2},

transverse relaxation rate) in a postprocessing step 21,28,29 .…”

Section: Methodsmentioning

confidence: 99%

“…transverse relaxation rate) in a post-processing step 21,30,31 . The values are proportional to the delivered = 1/ 2 , 2 dose and therefore allow for range determination.…”

Section: Dose Readoutmentioning

confidence: 99%

Section: Accepted Articlementioning

confidence: 99%

See 1 more Smart Citation

Measurement‐based range evaluation for quality assurance of CBCT‐based dose calculations in adaptive proton therapy

Neppl

Kurz

Köpl³

et al. 2021

Medical Physics

Self Cite

View full text Add to dashboard Cite

show abstract

“…T2 image scans were acquired using a half‐Fourier single‐shot turbo spin‐echo (HASTE) sequence with the following acquisition parameters: repetition time = 4230 ms, echo time = 40, 353, 931, 1380 ms, pixel size = 1.4 × 1.4 mm 2 , slice thickness = 2.0 mm. R2 maps (R2 = 1/T2), which are linearly related to the radiation dose (Gy), were post‐processed and converted to 3D dose distributions by RTsafe 11,18 …”

Section: Methodsmentioning

confidence: 99%

Validation of PTV margin for Gamma Knife Icon frameless treatment using a PseudoPatient® Prime anthropomorphic phantom

Han

Diagaradjane

Luo

et al. 2020

J Applied Clin Med Phys

Self Cite

View full text Add to dashboard Cite

The Gamma Knife Icon allows the treatment of brain tumors mask‐based single‐fraction or fractionated treatment schemes. In clinic, uniform axial expansion of 1 mm around the gross tumor volume (GTV) and a 1.5 mm expansion in the superior and inferior directions are used to generate the planning target volume (PTV). The purpose of the study was to validate this margin scheme with two clinical scenarios: (a) the patient’s head remaining right below the high‐definition motion management (HDMM) threshold, and (b) frequent treatment interruptions followed by plan adaptation induced by large pitch head motion. A remote‐controlled head assembly was used to control the motion of a PseudoPatient® Prime head phantom; for dosimetric evaluations, an ionization chamber, EBT3 films, and polymer gels were used. These measurements were compared with those from the Gamma Knife plan. For the absolute dose measurements using an ionization chamber, the percentage differences for both targets were less than 3.0% for all scenarios, which was within the expected tolerance. For the film measurements, the two‐dimensional (2D) gamma index with a 2%/2 mm criterion showed the passing rates of ≥87% in all scenarios except the scenario 1. The results of Gel measurements showed that GTV (D100) was covered by the prescription dose and PTV (D95) was well above the planned dose by up to 5.6% and the largest geometric PTV offset was 0.8 mm for all scenarios. In conclusion, the current margin scheme with HDMM setting is adequate for a typical patient’s intrafractional motion.

show abstract

“…Various studies have analyzed the MRI response of polymer gels for possible application in radiotherapy dose mapping ( [58,63] and references therein). In particular, polymer gels have been investigated for dosimetry in conformal therapy, IMRT, IMAT, IGRT, VMAT and tomotherapy [55,70,83,88,102,, small photon fields [136][137][138], stereotactic radiosurgery [55,[139][140][141][142], 60-cobalt source [143,144], brachytherapy [55,85,92,[145][146][147][148][149], cyberknife [150], gamma-knife [151], low-energy X-rays [152,153], high-LET and proton therapy [55,154,155], boron capture neutron therapy [55,[156][157][158][159], for interface dosimetry in the presence of tissue inhomogeneities [55,160,161], for X-ray tubes [162] and for diagnostic nuclear medicine [163]. Recently, polyacrilamide gels were proposed for dosimetry and end-to-end test for MRI-linac apparatus [164]…”

Section: Characterization and Performancementioning

confidence: 99%

Hydrogels for Three-Dimensional Ionizing-Radiation Dosimetry

Marrale

D’Errico

2021

Gels

View full text Add to dashboard Cite

Radiation-sensitive gels are among the most recent and promising developments for radiation therapy (RT) dosimetry. RT dosimetry has the twofold goal of ensuring the quality of the treatment and the radiation protection of the patient. Benchmark dosimetry for acceptance testing and commissioning of RT systems is still based on ionization chambers. However, even the smallest chambers cannot resolve the steep dose gradients of up to 30–50% per mm generated with the most advanced techniques. While a multitude of systems based, e.g., on luminescence, silicon diodes and radiochromic materials have been developed, they do not allow the truly continuous 3D dose measurements offered by radiation-sensitive gels. The gels are tissue equivalent, so they also serve as phantoms, and their response is largely independent of radiation quality and dose rate. Some of them are infused with ferrous sulfate and rely on the radiation-induced oxidation of ferrous ions to ferric ions (Fricke-gels). Other formulations consist of monomers dispersed in a gelatinous medium (Polyacrylamide gels) and rely on radiation-induced polymerization, which creates a stable polymer structure. In both gel types, irradiation causes changes in proton relaxation rates that are proportional to locally absorbed dose and can be imaged using magnetic resonance imaging (MRI). Changes in color and/or opacification of the gels also occur upon irradiation, allowing the use of optical tomography techniques. In this work, we review both Fricke and polyacrylamide gels with emphasis on their chemical and physical properties and on their applications for radiation dosimetry.

show abstract

Gel dosimetry for three dimensional proton range measurements in anthropomorphic geometries

Cited by 24 publications

References 46 publications

Measurement‐based range evaluation for quality assurance of CBCT‐based dose calculations in adaptive proton therapy

Measurement‐based range evaluation for quality assurance of CBCT‐based dose calculations in adaptive proton therapy

Validation of PTV margin for Gamma Knife Icon frameless treatment using a PseudoPatient® Prime anthropomorphic phantom

Hydrogels for Three-Dimensional Ionizing-Radiation Dosimetry

Contact Info

Product

Resources

About