Microscopic Gold Particle-Based Fiducial Markers for Proton Therapy of Prostate Cancer

Lim, Young Kyung; Kwak, Jungwon; Kim, Dong Wook; Shin, Dongho; Yoon, Myonggeun; Park, Soah; Kim, Jin Sung; Ahn, Sung Hwan; Shin, J; Lee, Se Byeong; Park, Sung Yong; Pyo, Hong Ryeol; Kim, Dae Yong; Cho, Kwan Ho

doi:10.1016/j.ijrobp.2009.02.076

Cited by 31 publications

(25 citation statements)

References 37 publications

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“…While MCS is important, energy loss in the fiducial (or its water-equivalent thickness), the proximity of the fiducial to the end of the proton beam range, and of course its size and orientation with respect to the beam also should be considered. The physics of dose perturbations is explained in detail elsewhere (Newhauser et al, (2007a), and several subsequent studies (Giebeler et al , 2009; Lim et al , 2009; Cheung et al , 2010; Huang et al , 2011) have shown that it is possible to achieve good radiographic visibility using novel markers that do not significantly perturb the therapeutic dose distribution in tissue.…”

Section: Proton Interaction Mechanismsmentioning

confidence: 99%

The physics of proton therapy

2015

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The physics of proton therapy has advanced considerably since it was proposed in 1946. Today analytical equations and numerical simulation methods are available to predict and characterize many aspects of proton therapy. This article reviews the basic aspects of the physics of proton therapy, including proton interaction mechanisms, proton transport calculations, the determination of dose from therapeutic and stray radiations, and shielding design. The article discusses underlying processes as well as selected practical experimental and theoretical methods. We conclude by briefly speculating on possible future areas of research of relevance to the physics of proton therapy.

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Section: Proton Interaction Mechanismsmentioning

confidence: 99%

The physics of proton therapy

2015

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“…[5][6][7] Several proposals to mitigate dose distortion have been made such as the reduction of marker size, 7 the optimization of marker compounds with carbon-coated ceramic 8 or mixture of microscopic gold particles and polymers. 9 An alternate solution may be to diminish the dose distortion effect by increasing the number of fields. 10 Because proton pencil beam scanning technique does not require replacement of the apertures and range compensators field by field, the treatment time will not be increased so much by the use of multiple fields.…”

Section: Introductionmentioning

confidence: 99%

Biological effect of dose distortion by fiducial markers in spot‐scanning proton therapy with a limited number of fields: A simulation study

et al. 2012

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Purpose: In accurate proton spot-scanning therapy, continuous target tracking by fluoroscopic X-ray during irradiation is beneficial not only for respiratory moving tumors of lung and liver but also for relatively stationary tumors of prostate. Implanted gold markers have been used with great effect for positioning the target volume by a fluoroscopy, especially for the cases of liver and prostate with the targets surrounded by water-equivalent tissues.However, recent studies have revealed that gold markers can cause a significant underdose in proton therapy. This paper focuses on prostate cancer and explores the possibility that multiple-field irradiation improves the underdose effect by markers on Tumor Control Probability (TCP). Methods:A Monte Carlo simulation was performed to evaluate the dose distortion effect. A spherical gold marker was placed at several characteristic points in a water phantom. Markers were with two different diameters of 2 mm and 1.5 mm, both visible on fluoroscopy. Three beam arrangements of SFUD (single-field uniform dose)were examined: one lateral field, two opposite lateral fields, and three fields (two opposite lateral fields + anterior field). The Relative Biological Effectiveness (RBE) was set to 1.1 and a dose of 74 Gy (RBE) was delivered to the target of a typical prostate size in 37 fractions. The ratios of TCP to that without the marker (TCP r ) were compared with the parameters of the marker sizes, number of fields, and marker positions. To take into account the dependence of biological parameters in TCP model,  values of 1.5, 3, and 10 Gy (RBE) were considered.Results: It was found that the marker of 1.5 mm diameter does not affect the TCPs with all  values when two or more fields are used. On the other hand, if the marker size is 2 mm, more than two irradiation fields are required to suppress the decrease in TCP from TCP r by less than 3%. This is especially true when multiple (two or three) markers are used for alignment of a patient. Conclusions:It is recommended that 1.5 mm markers be used to avoid the reduction of TCP as well as to spare the surrounding critical organs, as long as the markers are visible on X-ray fluoroscopy. When 2 mm markers are implanted, more than two fields should be used and the markers should not be placed close to the distal edge of any of the beams.

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“…In such a scenario, the analysis of the detected spectrum could assess whether the metallic structure was or was not located along the beam path during the treatment. Further clinical applicability may include patient with implanted seeds 45,46 . In general, this considerations are valid for high‐Z materials that, in contrast to light nuclei, emit prompt gamma radiation mainly in the low‐energy component of the spectrum.…”

Section: Discussionmentioning

confidence: 99%

“…Further clinical applicability may include patient with implanted seeds. 45,46 In general, this considerations are valid for high-Z materials that, in contrast to light nuclei, emit prompt gamma radiation mainly in the low-energy component of the spectrum. Additionally, the annihilation line E c ¼ 0:511 MeV could also be measured (not shown).…”

Section: Discussionmentioning

confidence: 99%

Results from the experimental evaluation of CeBr scintillators for He prompt gamma spectroscopy

et al. 2019

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Purpose The presence of range uncertainties hinders the exploitation of the full potential of charged particle therapy. Several range verification techniques have been proposed to mitigate this limitation. Prompt gamma spectroscopy (PGS) is among the most promising solutions for online and in vivo range verification. In this work, we present the experimental results of the detection of prompt gamma radiation, induced by 4He beams at the Heidelberg Ion‐Beam Therapy Center (HIT). The results were obtained, using a spectroscopic unit of which the design has been optimized using Monte Carlo simulations. Methods The spectroscopic unit is composed by a primary cerium bromide (CeBr3) crystal surrounded by a secondary bismuth germanate (BGO) crystal for anticoincidence detection (AC). The digitalization of the signals is performed with an advanced FADC/FPGA system. The 4He beams at clinical energies and intensities are delivered to multiple targets in the experimental cave at the HIT. We analyze the production of prompt gamma on oxygen and carbon targets, as well as high Z materials such as titanium and aluminum. The quantitative analysis includes a systematic comparison of the signal‐to‐noise ratio (SNR) improvement for the spectral lines when introducing the AC detection. Moreover, the SNR improvement could provide a reduction of the number of events required to draw robust conclusions. We perform a statistic analysis to determine the magnitude of such an effect. Results We present the energy spectra detected by the primary CeBr3 and the secondary BGO. The combination of these two detectors leads to an average increase of the signal‐to‐noise ratio by a factor 2.1, which confirms the Monte Carlo predictions. The spectroscopic unit is capable of detecting efficiently the discrete gamma emission over the full energy spectrum. We identify and analyze 19 independent spectral lines in an energy range spacing from Eγ=0.718 MeV to Eγ=6.13 MeV. Moreover, when introducing the AC detection, the number of events required to determine robustly the intensity of the discrete lines decreases. Finally, the analysis of the low‐energy reaction lines determines whether a thin metal insert is introduced in the beam direction. Conclusions This work provides the experimental characterization of the spectroscopy unit in development for range verification through PGS at the HIT. Excellent performances have been demonstrated over the full prompt gamma energy spectrum with 4He beams at clinical energies and intensities.

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Microscopic Gold Particle-Based Fiducial Markers for Proton Therapy of Prostate Cancer

Cited by 31 publications

References 37 publications

The physics of proton therapy

The physics of proton therapy

Biological effect of dose distortion by fiducial markers in spot‐scanning proton therapy with a limited number of fields: A simulation study

Results from the experimental evaluation of CeBr scintillators for He prompt gamma spectroscopy

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