The ideal dosimeter for intensity modulated radiation therapy (IMRT): What is required?

Wagter, C. De

doi:10.1088/1742-6596/3/1/002

Cited by 23 publications

(19 citation statements)

References 2 publications

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“…However, gel dosimetry should be used as a dosimetric tool to verify dose distributions obtained with treatment planning of class solutions (De Wagter 2004). …”

Section: Applications Of Polymer Gel Dosimetrymentioning

confidence: 99%

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Polymer gel dosimetry

et al. 2010

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Polymer gel dosimeters are fabricated from radiation sensitive chemicals which, upon irradiation, polymerize as a function of the absorbed radiation dose. These gel dosimeters, with the capacity to uniquely record the radiation dose distribution in three-dimensions (3D), have specific advantages when compared to one-dimensional dosimeters, such as ion chambers, and two-dimensional dosimeters, such as film. These advantages are particularly significant in dosimetry situations where steep dose gradients exist such as in intensity-modulated radiation therapy (IMRT) and stereotactic radiosurgery. Polymer gel dosimeters also have specific advantages for brachytherapy dosimetry. Potential dosimetry applications include those for low-energy x-rays, high-linear energy transfer (LET) and proton therapy, radionuclide and boron capture neutron therapy dosimetries. These 3D dosimeters are radiologically soft-tissue equivalent with properties that may be modified depending on the application. The 3D radiation dose distribution in polymer gel dosimeters may be imaged using magnetic resonance imaging (MRI), optical-computerized tomography (optical-CT), x-ray CT or ultrasound. The fundamental science underpinning polymer gel dosimetry is reviewed along with the various evaluation techniques. Clinical dosimetry applications of polymer gel dosimetry are also presented.

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“…However, gel dosimetry should be used as a dosimetric tool to verify dose distributions obtained with treatment planning of class solutions (De Wagter 2004). …”

Section: Applications Of Polymer Gel Dosimetrymentioning

confidence: 99%

“…(b) Methodology and tools appropriate for each of the levels. EPID stands for ‘electronic portal imaging’ (De Wagter et al 2004). Reproduced with permission.…”

Section: Figures and Tablesmentioning

confidence: 99%

Polymer gel dosimetry

et al. 2010

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“…It is necessary to verify the agreement between dose distributions calculated by a radiation treatment planning system (RTPS) and delivered by a linear accelerator (linac) for intensity modulated radiation therapy (IMRT) . A number of approaches and systems have been developed for this verification . Recently, three‐dimensional (3D) dose verification systems consisting of a solid phantom and detector arrays have become commercially available.…”

Section: Introductionmentioning

confidence: 99%

Density scaling of phantom materials for a 3D dose verification system

Tani

Fujita

Wakita³

et al. 2018

J Applied Clin Med Phys

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In this study, the optimum density scaling factors of phantom materials for a commercially available three‐dimensional (3D) dose verification system (Delta4) were investigated in order to improve the accuracy of the calculated dose distributions in the phantom materials. At field sizes of 10 × 10 and 5 × 5 cm2 with the same geometry, tissue‐phantom ratios (TPRs) in water, polymethyl methacrylate (PMMA), and Plastic Water Diagnostic Therapy (PWDT) were measured, and TPRs in various density scaling factors of water were calculated by Monte Carlo simulation, Adaptive Convolve (AdC, Pinnacle3), Collapsed Cone Convolution (CCC, RayStation), and AcurosXB (AXB, Eclipse). Effective linear attenuation coefficients (μ eff) were obtained from the TPRs. The ratios of μ eff in phantom and water ((μ eff)pl,water) were compared between the measurements and calculations. For each phantom material, the density scaling factor proposed in this study (DSF) was set to be the value providing a match between the calculated and measured (μ eff)pl,water. The optimum density scaling factor was verified through the comparison of the dose distributions measured by Delta4 and calculated with three different density scaling factors: the nominal physical density (PD), nominal relative electron density (ED), and DSF. Three plans were used for the verifications: a static field of 10 × 10 cm2 and two intensity modulated radiation therapy (IMRT) treatment plans. DSF were determined to be 1.13 for PMMA and 0.98 for PWDT. DSF for PMMA showed good agreement for AdC and CCC with 6 MV x ray, and AdC for 10 MV x ray. DSF for PWDT showed good agreement regardless of the dose calculation algorithms and x‐ray energy. DSF can be considered one of the references for the density scaling factor of Delta4 phantom materials and may help improve the accuracy of the IMRT dose verification using Delta4.

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“…There are many studies regarding the characteristics of these detectors, uses of these detectors for patient specific quality assurance (QA) and machine QA (3)(4)(5)(6)(7)(8)(9). Because of the modifications in the design of detectors, their characteristics as well as the introduction of new techniques in radiotherapy, feasibility of these detectors to use as an ideal dosimeter for patient specific QA of IMRT and rapid arc is still a subject of controversy [10,11]. This study aimed to compare the Varian portal dosimetry system and the ImatriXX 2-D array system of IBA dosimetry for IMRT and rapid arc patient specific QA…”

Section: Introductionmentioning

confidence: 99%

Study of feasibility of portal dosimetry in comparison with ImatriXX 2-D array system for IMRT and Rapid arc patient specific QA.

Surendran¹,

Rao²,

Cyriac³

et al. 2014

IOSRJEN

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-This study aimed to compare the Varian portal dosimetry system and the ImatriXX 2-D array system of IBA dosimetry for IMRT and Rapid arc patient specific quality assurance (QA). Fifteen cases of IMRT and fifteen cases of Rapid arc plans were selected for the patient specific QA study using portal dosimetry and ImatriXX 2-D array system. Planar dose comparison was carried out with gamma criteria of 3% -3 mm {dose difference and distance-to-agreement (DTA)}. For portal dosimetry system area gamma, average gamma and maximum gamma were analyzed and for the ImatriXX 2-D array system, the % of pixels passing the 3%-3mm gamma was chosen. In case of IMRT, the portal dosimetry mean values of area gamma, average gamma and maximum gamma were 1.01, 0.48 and 1.72 with standard deviation values of 0.38, 0.05 and 0.20 and for Rapid arc the corresponding values were 2.01, 0.48 and 1.72 with standard deviation of 0.54, 0.07 and 0.29. With the ImatriXX 2-D array system, on an average 99.22% of the pixels passed the criteria of 3%-3 mm with standard deviation of 0.58 for IMRT. For rapid arc, the average value was 97.14% with a standard deviation of 1.26. The results showed that both the systems can be use for patient specific QA measurements for IMRT and rapid arc. Portal dosimetry as well as ImatriXX measurements showed significant difference in gamma results of IMRT vs. rapid arc with pvalue less than 0.05. Compared to ImatriXX 2-D array system, the portal dosimetry values were more consistent. The portal dosimetry QA is less time consuming and in case of IMRT individual field verification is easier compared to ImatriXX 2-D array system.

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The ideal dosimeter for intensity modulated radiation therapy (IMRT): What is required?

Cited by 23 publications

References 2 publications

Polymer gel dosimetry

Polymer gel dosimetry

Density scaling of phantom materials for a 3D dose verification system

Study of feasibility of portal dosimetry in comparison with ImatriXX 2-D array system for IMRT and Rapid arc patient specific QA.

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