Radiobiology

Beyzadeoğlu, Murat; Özyiğit, Gökhan; Ebruli, Cuneyt

doi:10.1007/978-3-642-11666-7_2

Cited by 6 publications

(7 citation statements)

References 35 publications

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“…HEF was introduced in Equation 4 in the similar way that the oxygen enhancement ratio (OER) was introduced for acute hypoxia [ 17 , 18 ]. Equation 5 was designed to give HEF = 1 for patients having a Hb level of 13 g/dL, which is a normal value.…”

Section: Methodsmentioning

confidence: 99%

Hemoglobin level significantly impacts the tumor cell survival fraction in humans after internal radiotherapy

et al. 2012

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BackgroundAnemia is usually not taken into account in internal radiotherapy. We investigated whether the hemoglobin (Hb) level could have an impact on the tumor response, as observed in external beam radiotherapy (EBRT).MethodsAbsorbed doses of 25 hepatic metastatic sites in eight patients who underwent a liver selective internal radiotherapy (SIRT) were computed by a 3D convolution of a dose deposition kernel with the 90Y time-of-flight positron emission tomography (TOF-PET) images acquired following therapy. Early tumor response was assessed by comparing a follow-up FDG TOF-PET scan with a baseline scan. Hb level was measured on the day of the SIRT procedure.ResultsAll patients displayed early tumor response increasing with the tumor-absorbed dose. Significant differences between patients were noted, the response slope correlating with the Hb level. After applying a global fit on all metastases using a tumor radiosensitivity modulated by a Hb enhancement factor (HEF) linearly dependent on the Hb level, a strong correlation (R = 0.96) was observed between the early response and the absorbed dose. Hb level had a major impact on tumor response by modulating HEF by a factor 6.ConclusionsThese results prove the significant impact of Hb level on the tumor response and support the study of methods for correcting tumor hypoxia, such as intensively performed in EBRT. The quantitative analysis of the relationship between tumor doses and early response has the power to allow fast screening of such correction methods in limited patient series. Internal radiotherapy could be more efficient if performed earlier in the therapy line, when the disease- and treatment-related anemia remains limited.

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Section: Methodsmentioning

confidence: 99%

Hemoglobin level significantly impacts the tumor cell survival fraction in humans after internal radiotherapy

et al. 2012

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“…15 Radiosensitivity of a cell can be 4-fold greater during the mitotic phase than during the interphase. 16 Thus, it is possible that more rapidly dividing and highly metabolic tumors would be more responsive to radiotherapy and do worse.…”

Section: Discussionmentioning

confidence: 99%

Regression of Uveal Melanoma After Ru-106 Brachytherapy and Thermotherapy Based on Metabolic Activity Measured by Positron Emission Tomography/Computed Tomography

Lee

Lee²,

Lee³

et al. 2014

Retina

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“…Hypoxia presents in almost all solid tumors and is both an important factor driving tumor progression and a leading obstacle to therapeutic efforts. − Oxygen insufficiency significantly inhibits the generation of appreciable amounts of ROS, leading to a failure to destroy tumor tissues. Meanwhile, previous studies have reported that PDT-mediated oxygen consumption can further increase hypoxic degree, leading to additional adverse consequences such as recurrence or metastasis. − Clinically, researchers have found that hypoxic tumor cells cannot be effectively killed by radiotherapy due to the fact that normal RT is also obviously affected by the amount of O 2 to ensure maximum cell death, namely, the hypoxia due to the consumption of O 2 decreases cellular radiosensitivity and thus fails to “fix” DNA damage during RT. , Feasible strategies to overcome these limitations include delivery of oxygen to tumors, development of oxygen-generating manganese dioxide nanoparticles, or incorporation of antiangiogenesis therapy . Recently, with rapid developments in X-PDT, the issue of hypoxia has also been discussed in this field, with strategies including employment of X-ray excited type-I PDT, NO generation, and oncolytic bacterium therapy proposed to conquer tumor hypoxia and achieve low-dose X-PDT.…”

Section: Strategies To Achieve Low Radiation Dose In X-pdtmentioning

confidence: 99%

“…132−134 Clinically, researchers have found that hypoxic tumor cells cannot be effectively killed by radiotherapy due to the fact that normal RT is also obviously affected by the amount of O 2 to ensure maximum cell death, namely, the hypoxia due to the consumption of O 2 decreases cellular radiosensitivity and thus fails to "fix" DNA damage during RT. 81,135 Feasible strategies to overcome these limitations include delivery of oxygen to tumors, 87 development of oxygengenerating manganese dioxide nanoparticles, 136 or incorporation of antiangiogenesis therapy. 137 Recently, with rapid developments in X-PDT, the issue of hypoxia has also been discussed in this field, with strategies including employment of X-ray excited type-I PDT, NO generation, and oncolytic bacterium therapy proposed to conquer tumor hypoxia and achieve low-dose X-PDT.…”

Section: Strategies To Overcome Local Hypoxic Tumor Microenvironmentmentioning

confidence: 99%

Recent Progress and Trends in X-ray-Induced Photodynamic Therapy with Low Radiation Doses

2022

ACS Nano

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The prominence of photodynamic therapy (PDT) in treating superficial skin cancer inspires innovative solutions for its congenitally deficient shadow penetration of the visible-light excitation. X-ray-induced photodynamic therapy (X-PDT) has been proven to be a successful technique in reforming the conventional PDT for deep-seated tumors by creatively utilizing penetrating X-rays as external excitation sources and has witnessed rapid developments over the past several years. Beyond the proof-of-concept demonstration, recent advances in X-PDT have exhibited a trend of minimizing X-ray radiation doses to quite low values. As such, scintillating materials used to bridge X-rays and photosensitizers play a significant role, as do diverse well-designed irradiation modes and smart strategies for improving the tumor microenvironment. Here in this review, we provide a comprehensive summary of recent achievements in X-PDT and highlight trending efforts using low doses of X-ray radiation. We first describe the concept of X-PDT and its relationships with radiodynamic therapy and radiotherapy and then dissect the mechanism of X-ray absorption and conversion by scintillating materials, reactive oxygen species evaluation for X-PDT, and radiation side effects and clinical concerns on X-ray radiation. Finally, we discuss a detailed overview of recent progress regarding low-dose X-PDT and present perspectives on possible clinical translation. It is expected that the pursuit of low-dose X-PDT will facilitate significant breakthroughs, both fundamentally and clinically, for effective deep-seated cancer treatment in the near future.

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Radiobiology

Cited by 6 publications

References 35 publications

Hemoglobin level significantly impacts the tumor cell survival fraction in humans after internal radiotherapy

Hemoglobin level significantly impacts the tumor cell survival fraction in humans after internal radiotherapy

Regression of Uveal Melanoma After Ru-106 Brachytherapy and Thermotherapy Based on Metabolic Activity Measured by Positron Emission Tomography/Computed Tomography

Recent Progress and Trends in X-ray-Induced Photodynamic Therapy with Low Radiation Doses

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