Calculation of relative biological effectiveness of a low-energy electronic brachytherapy source

Reniers, Brigitte; Liu, Derek; Rusch, Thomas W.; Verhaegen, Frank

doi:10.1088/0031-9155/53/24/008

Cited by 50 publications

(51 citation statements)

References 34 publications

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“…Thus, photons emitted in a treatment with Esteya ® have considerably lower energy than photons emitted by a 192 Ir source. It has been reported that lower energy photons have a higher radiobiological effectiveness (RBE) [17]. This implies that a lower physical dose should be prescribed with EBT sources in order to achieve the same clinical results (i.e.…”

Section: Rationale For the Study Fractionation Schedulesmentioning

confidence: 99%

Electronic brachytherapy for superficial and nodular basal cell carcinoma: a report of two prospective pilot trials using different doses

Ballester‐Sánchez¹,

Pons-Llanas

Candela-Juan

et al. 2016

jcb

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Purpose: Basal cell carcinoma (BCC) is a very common cancer in the Caucasian population. Treatment aims to eradicate the tumor with the lowest possible functional and aesthetic impact. Electronic brachytherapy (EBT) is a treatment technique currently emerging. This study aims to show the outcomes of two consecutive prospective pilot clinical trials using different radiation doses of EBT with Esteya ® EB system for the treatment of superficial and nodular basal cell carcinoma.Material and methods: Two prospective, single-center, non-randomized, pilot studies were conducted. Twenty patients were treated in each study with different doses. The first group (1) was treated with 36.6 Gy in 6 fractions of 6.1 Gy, and the second group (2) with 42 Gy in 6 fractions of 7 Gy. Cure rate, acute toxicity, and late toxicity related to cosmesis were analyzed in the two treatment groups.Results: In group 1, a complete response in 90% of cases was observed at the first year of follow-up, whereas in group 2, the complete response was 95%. The differences with reference to acute toxicity and the cosmetic results between the two treatment groups were not statistically significant.Conclusions: Our initial experience with Esteya ® EB system to treat superficial and nodular BCC shows that a dose of 36.6 Gy and 42 Gy delivered in 6 fraction of 7 Gy achieves a 90% and 95% clinical cure rate at 1 year, respectively. Both groups had a tolerable toxicity and a very good cosmesis. The role of EBT in the treatment of BCC is still to be defined. It will probably become an established option for selected patients in the near future.

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Section: Rationale For the Study Fractionation Schedulesmentioning

confidence: 99%

Electronic brachytherapy for superficial and nodular basal cell carcinoma: a report of two prospective pilot trials using different doses

Ballester‐Sánchez¹,

Pons-Llanas

Candela-Juan

et al. 2016

jcb

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“…2, chargedparticle stopping power in water is equated to the stopping power of an a particle with the same (Z eff /b) 2 . For photons, the MCDS computes a fluence-averaged stopping power from the spectrum of secondary electrons arising when the (primary) photon first interacts in or near the cell nucleus (61,62). The MCDS also has the capability to estimate the fluence-averaged stopping power for a mixture of ions with the same or different kinetic energy.…”

Section: 200mentioning

confidence: 99%

Effects of Radiation Quality and Oxygen on Clustered DNA Lesions and Cell Death

et al. 2011

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Radiation quality and cellular oxygen concentration have a substantial impact on DNA damage, reproductive cell death and, ultimately, the potential efficacy of radiation therapy for the treatment of cancer. To better understand and quantify the effects of radiation quality and oxygen on the induction of clustered DNA lesions, we have now extended the Monte Carlo Damage Simulation (MCDS) to account for reductions in the initial lesion yield arising from enhanced chemical repair of DNA radicals under hypoxic conditions. The kinetic energy range and types of particles considered in the MCDS have also been expanded to include charged particles up to and including (56)Fe ions. The induction of individual and clustered DNA lesions for arbitrary mixtures of different types of radiation can now be directly simulated. For low-linear energy transfer (LET) radiations, cells irradiated under normoxic conditions sustain about 2.9 times as many double-strand breaks (DSBs) as cells irradiated under anoxic conditions. New experiments performed by us demonstrate similar trends in the yields of non-DSB (Fpg and Endo III) clusters in HeLa cells irradiated by γ rays under aerobic and hypoxic conditions. The good agreement among measured and predicted DSBs, Fpg and Endo III cluster yields suggests that, for the first time, it may be possible to determine nucleotide-level maps of the multitude of different types of clustered DNA lesions formed in cells under reduced oxygen conditions. As particle LET increases, the MCDS predicts that the ratio of DSBs formed under normoxic to hypoxic conditions by the same type of radiation decreases monotonically toward unity. However, the relative biological effectiveness (RBE) of higher-LET radiations compared to (60)Co γ rays (0.24 keV/μm) tends to increase with decreasing oxygen concentration. The predicted RBE of a 1 MeV proton (26.9 keV/μm) relative to (60)Co γ rays for DSB induction increases from 1.9 to 2.3 as oxygen concentration decreases from 100% to 0%. For a 12 MeV (12)C ion (681 keV/μm), the 'predicted RBE for DSB induction increases from 3.4 (100% O(2)) to 9.8 (0% O(2)). Estimates of linear-quadratic (LQ) cell survival model parameters (α and β) are closely correlated to the Monte Carlo-predicted trends in DSB induction for a wide range of particle types, energies and oxygen concentrations. The analysis suggests α is, as a first approximation, proportional to the initial number of DSBs per cell, and β is proportional to the square of the initial number of DSBs per cell. Although the reported studies provide some evidence supporting the hypothesis that DSBs are a biologically critical form of clustered DNA lesion, the induction of Fpg and Endo III clusters in HeLa cells irradiated by γ rays exhibits similar trends with oxygen concentration. Other types of non-DSB cluster may still play an important role in reproductive cell death. The MCDS captures many of the essential trends in the formation of clustered DNA lesions by ionizing radiation and provides useful information to probe the mu...

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“…Because of the low photon energy of EB, the difference in the biologic effectiveness of EB and the HDR technique also needs to be considered. It is well established that the relative biologic effectiveness (RBE) of photons increases with decreasing photon energy, corresponding to the increase in the linear energy transfer (27)(28)(29)(30)(31)(32)(33)(34)(35). Therefore, not surprisingly, RBE values in the range of 1.50-1.62 for 40 to 50 kV X-rays (0.0-0.7 mm Al filters) relative to 60 Co g-rays were measured for the 10% survival of V79 cells (Chinese hamster cells) (30).…”

Section: Discussionmentioning

confidence: 99%