The Dosimetric Impact of Shifts in Patient Positioning during Boron Neutron Capture Therapy for Brain Tumors

Lee, Jia Cheng; Chen, Yi Wei; Chuang, Keh Shih; Hsu, F.Y.; Chou, Fong‐In; Hsu, Shih Ming; Yen, Sang Hue; Wu, Yuan‐Hung

doi:10.1155/2018/5826174

Cited by 7 publications

(11 citation statements)

References 12 publications

(18 reference statements)

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“…reduction due to SI or LR (lateral) shifts was significantly greater for smaller collimator sizes on both T 2.5 and T 6.5 and smaller CSD on T 2.5 , according to the Student's t-test. There were no significant differences in the DIs against both the AP shift and the lateral shift between the different T/B ratios and 10 B concentrations.…”

mentioning

confidence: 76%

“…A cylindrical phantom (16 cm diameter × 20 cm height) similar to that used in the study of Lee et al 10 was modeled in the TPS.The phantom was made with homogeneous "Tissue soft" registered using RayStation. The mass density of the phantom was set to 1.000 g/cm 3 and was composed of hydrogen, carbon, nitrogen, and oxygen with elemental weights of 0.101, 0.111, 0.026, and 0.762, respectively.…”

Section: Phantom Modelmentioning

confidence: 99%

“…To accurately calculate the dose, several treatment parameters are required for BNCT dose calculation, such as the tumor-to-blood boron concentration ratio (T/B ratio) and blood 10 B concentration. 8 The T/B ratio is the ratio corresponding to the standardized uptake values (SUVs) calculated by positron emission tomography using 18 F-fluoro-borono-phenylalanine (FBPA-PET); this is used to estimate the boron concentration in the tumor.…”

Section: Introductionmentioning

confidence: 99%

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Comprehensive evaluation of dosimetric impact against position errors in accelerator‐based BNCT under different treatment parameter settings

Kakino

Isohashi

et al. 2022

Medical Physics

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Background Patients who undergo accelerator‐based (AB) boron neutron capture therapy (BNCT) for head and neck cancer in the sitting position are generally uncomfortably immobilized, and patient motion during this treatment may be greater than that in other radiotherapy techniques. Furthermore, the treatment time of BNCT is relatively long (up to approximately 1 h), which increases the possibility of patient movement during treatment. As most BNCT irradiations are performed in a single fraction, the dosimetric error due to patient motion is of greater consequence and needs to be evaluated and accounted for. Several treatment parameters are required for BNCT dose calculation. Purpose To investigate the dosimetric impacts (DIs) against position errors using a simple cylindrical phantom for an AB‐BNCT system under different treatment parameter settings. Methods The treatment plans were created in RayStation and the dose calculation was performed using the NeuCure® dose engine. A cylindrical phantom (16 cm diameter × 20 cm height) made of soft tissue was modeled. Dummy tumors in the form of a 3‐cm‐diameter sphere were arranged at depths of 2.5 and 6.5 cm (denoted by T2.5 and T6.5, respectively). Reference plans were created by setting the following parameters: collimator size = 10, 12, or 15 cm in diameter, collimator‐to‐surface distance (CSD) = 4.0 or 8.0 cm, tumor‐to‐blood ratio (T/B ratio) using 18F‐fluoro‐borono‐phenylalanine = 2.5 or 5.0, and 10B concentration in blood = 20, 25, or 30 ppm. The prescribed dose was D95% ≥ 20 Gy‐eq for both T2.5 and T6.5. Based on the reference plans, phantom‐shifted plans were created in 26 directions [all combinations of left–right (LR), anterior–posterior (AP), and superior–inferior (SI) directions) and three distances (1.0, 2.0, and 3.0 cm). The DIs were evaluated at D80% of the tumors. The shift direction dependency of the DI in the LR, AP, and SI directions was evaluated by conducting a multiple regression analysis (MRA) and other analyses where required. Results The coefficients of the MRA of the DIs for LR, AP, and SI shifts were −0.08, 2.16, and −0.04 (p‐values = 0.084, <0.01, and 0.334) for T2.5 and −0.05, 2.08, and 0.15 (p‐values = 0.526, <0.01, and 0.065) for T6.5, respectively. The analysis of variance showed that DIs due to the AP shift were significantly greater for smaller collimator sizes on T2.5 and smaller CSD on T6.5. Dose reduction due to SI or LR (lateral) shifts was significantly greater for smaller collimator sizes on both T2.5 and T6.5 and smaller CSD on T2.5, according to the Student's t‐test. There were no significant differences in the DIs against both the AP shift and the lateral shift between the different T/B ratios and 10B concentrations. Conclusion The DIs were largely affected by the shift in the AP direction and were influenced by the different treatment parameters.

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confidence: 76%

Section: Phantom Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Comprehensive evaluation of dosimetric impact against position errors in accelerator‐based BNCT under different treatment parameter settings

Kakino

Isohashi

et al. 2022

Medical Physics

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“…The need of a spatial realignment was highlighted by the non-negligible impact of patient positioning on the thermal/epithermal neutron flux estimation for dose planning. It was reported that a shift in patient positioning during treatment, but especially by set-up, has a relevant effect on dose estimation [ 14 ]. In fact, unlike conventional radiation therapies, sophisticated patient positioning tools are not available in BNCT.…”

Section: Multi-modal Imaging For Treatment Optimization and Response Evaluationmentioning

confidence: 99%

“…Furthermore, the positioning during imaging and during the treatment may be very different because the patient has to be brought directly to the rigid beam delivery system. It was found that a decrease in mean tumor dose results from high shift distances, and that dose distribution for brain tumors at greater depths would be more sensitive to patient motion [ 14 ].…”

Section: Multi-modal Imaging For Treatment Optimization and Response Evaluationmentioning

confidence: 99%

Theranostics in Boron Neutron Capture Therapy

Sauerwein

Sancey

Hey‐Hawkins

et al. 2021

Life

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Boron neutron capture therapy (BNCT) has the potential to specifically destroy tumor cells without damaging the tissues infiltrated by the tumor. BNCT is a binary treatment method based on the combination of two agents that have no effect when applied individually: 10B and thermal neutrons. Exclusively, the combination of both produces an effect, whose extent depends on the amount of 10B in the tumor but also on the organs at risk. It is not yet possible to determine the 10B concentration in a specific tissue using non-invasive methods. At present, it is only possible to measure the 10B concentration in blood and to estimate the boron concentration in tissues based on the assumption that there is a fixed uptake of 10B from the blood into tissues. On this imprecise assumption, BNCT can hardly be developed further. A therapeutic approach, combining the boron carrier for therapeutic purposes with an imaging tool, might allow us to determine the 10B concentration in a specific tissue using a non-invasive method. This review provides an overview of the current clinical protocols and preclinical experiments and results on how innovative drug development for boron delivery systems can also incorporate concurrent imaging. The last section focuses on the importance of proteomics for further optimization of BNCT, a highly precise and personalized therapeutic approach.

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Dosimetric effects of the ipsilateral shoulder position variations in the sitting-positioned boron neutron capture therapy for lower neck tumor

Kato

Hirose²,

Katō³

et al. 2022

Applied Radiation and Isotopes

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The Dosimetric Impact of Shifts in Patient Positioning during Boron Neutron Capture Therapy for Brain Tumors

Cited by 7 publications

References 12 publications

Comprehensive evaluation of dosimetric impact against position errors in accelerator‐based BNCT under different treatment parameter settings

Comprehensive evaluation of dosimetric impact against position errors in accelerator‐based BNCT under different treatment parameter settings

Theranostics in Boron Neutron Capture Therapy

Dosimetric effects of the ipsilateral shoulder position variations in the sitting-positioned boron neutron capture therapy for lower neck tumor

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