Clinical Radiation Oncology

This study aimed to expand the biological conversion factor (BCF) model, which converts the physical dosimetric margin (PDM) to the biological dosimetric margin (BDM) for point prescription with 3-dimensional conformal radiation therapy (3DCRT) and the marginal prescription method with volumetric-modulated arc radiotherapy (VMAT). The VMAT of the marginal prescription and the 3DCRT of the point prescription with lung stereotactic body radiation therapy (SBRT) by using RayStation were planned. The biological equivalent dose (BED) for a dose per fraction (DPF) of 3–20 Gy was calculated from these plans. The dose was perturbed with the calculation using a 1-mm step isocenter shift. The dose covering 95% of the target was greater than or equal to 90% of the prescribed physical dose, and the BED were defined as the PDM and BDM, respectively. The BCF was created as a function of the DPF. The PDM and BDM for all DPFs were larger with the point prescription method than with the marginal prescription method. The marginal prescription method with a 60% isodose line had a larger PDM and BDM. The BCF with the point prescription was smaller than that with the marginal prescription in the left–right (LR), anterior–posterior (AP) and cranio–caudal (CC) directions. In the marginal prescription method, the 60% isodose line had a higher BCF. In conclusion, the improved BCF method could be converted to BDM for point prescription with 3DCRT and marginal prescription method with VMAT, which is required for stereotactic radiation therapy in radiobiology-based treatment planning.

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“…The line curves are the results of the tting using Eq. (3,4) for the point and marginal prescriptions.…”

Section: Declarations Con Ict Of Interest Statementsmentioning

confidence: 99%

Physical and biological dosimetric margin according to prescription method for stereotactic body radiation therapy

Kawahara

Saito

Nagata

2023

Journal of Radiation Research

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“…Insidensi kanker serviks di Indonesia adalah sekitar 13/100.000 wanita dengan angka mortalitas sekitar 7/100.000 wanita. 2,10,12 Gambar 1 Gambar target radiasi dalam foto simulator untuk radioterapi konvensional 2 dimensi untuk lapangan antero-posterior dan postero-anterior…”

Section: Pendahuluanunclassified

The Role of Radiotherapy in Uterine Cervical Cancer

Kodrat

2018

JKM

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Uterine cervical cancer is the most common cancer in Indonesia. The purpose of the review is to describe diagnosis and staging, the basic principles of radiotherapy, the role of radiotherapy in cervical cancer treatment, and radiotherapy side effects. The goal of radiotherapy in cervical cancer consists of definitive, adjuvant, and palliative. Effort to increase radiation response also develops by administered small dose of chemotherapy as a radiosensitizer.Keywords: cancer, cervix, radiotherapy

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“…Moreover, we proposed a novel quantity, named biological dosimetric margin (BDM), which was a margin distribution considering the biological effect of the DM. The biological effect was introduced by calculating the BED using the LQ model 16 as an example biological model. The differences between the relative dose distribution of the PD and BED were calculated.…”

Section: Introductionmentioning

confidence: 99%

Assessment of biological dosimetric margin for stereotactic body radiation therapy

Kawahara

Saito

Ozawa

et al. 2020

J Applied Clin Med Phys

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Purpose: To develop a novel biological dosimetric margin (BDM) and to create a biological conversion factor (BCF) that compensates for the difference between physical dosimetric margin (PDM) and BDM, which provides a novel scheme of a direct estimation of the BDM from the physical dose (PD) distribution.Methods: The offset to isocenter was applied in 1-mm steps along left-right (LR), anterior-posterior (AP), and cranio-caudal (CC) directions for 10 treatment plans of lung stereotactic body radiation therapy (SBRT) with a prescribed dose of 48 Gy.These plans were recalculated to biological equivalent dose (BED) by the linearquadratic model for the dose per fraction (DPF) of d = 3-20 Gy/fr and α=β ¼ 3 À 10. BDM and PDM were defined so that the region that satisfied that the dose covering 95% (or 98%) of the clinical target volume was greater than or equal to the 90% of the prescribed PD and BED, respectively. An empirical formula of the BCF was created as a function of the DPF.Results: There was no significant difference between LR and AP directions for neither the PDM nor BDM. On the other hand, BDM and PDM in the CC direction were significantly larger than in the other directions. BCFs of D 95% and D 98% were derived for the transverse (LR and AP) and longitudinal (CC) directions. Conclusions:A novel scheme to directly estimate the BDM using the BCF was developed. This technique is expected to enable the BED-based SBRT treatment planning using PD-based treatment planning systems. K E Y W O R D S biological equivalent dose, dosimetric margin, LQ model, SBRT 1 | INTRODUCTION In modern radiation therapy, dose-volume histogram (DVH) and isodose distribution are commonly used for treatment evaluation. Dosevolume constraints indicate organ volumes that should not receive doses exceeding certain limits derived from retrospective studies.Clinical and radiobiological studies have shown that two treatments delivering the same total dose through different fractionation schemes produce different biological results. 1,2 Fowler showed that the biological effective dose (BED) modeling is a valuable tool for understanding tumor and normal tissue response across different treatment modalities and fractionation schemes. 3 Based on the idea of BED, it has been shown that the relative biological effectiveness depends on the dose per fraction (DPF) and the number of fractions.---

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Clinical Radiation Oncology

Cited by 6 publications

References 4 publications

Physical and biological dosimetric margin according to prescription method for stereotactic body radiation therapy

Physical and biological dosimetric margin according to prescription method for stereotactic body radiation therapy

The Role of Radiotherapy in Uterine Cervical Cancer

Assessment of biological dosimetric margin for stereotactic body radiation therapy

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