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Immunotherapy for Gliomas and Other Intracranial Malignancies
Published in Raj Bawa, János Szebeni, Thomas J. Webster, Gerald F. Audette, Immune Aspects of Biopharmaceuticals and Nanomedicines, 2019
Mario Ganau, Gianfranco K. I. Ligarotti, Salvatore Chibbaro, Andrea Soddu
Brain metastases are the most common intracranial malignancy and, despite advances in prevention and early diagnosis, their incidence has steadily risen over time. The cerebral blood flow represents 15% of the cardiac output, constantly, and primary tumors are known to escape local hypoxia by releasing in the bloodstream circulating tumor cells at an exponential rate. As such, it is no wonder that an estimated 25–45% of all cancers sooner or later will develop brain metastases, with lung and breast cancers showing a strong organotropism for the CNS [2, 3, 18]. Until recently, those lesions were considered as a homogenous condition, uniformly treated with whole brain radiotherapy alone or with surgical resection for large lesions and stereotactic radiosurgery for smaller lesions. Increasingly, specific systemic medical therapies are being used to treat brain metastases based on the primary site of disease, nonetheless, as of today; they still represent a devastating clinical reality, carrying an estimated survival time of less than one year in most of the cases [19].
Nanotechnology-Mediated Radiation Therapy
Published in D. Sakthi Kumar, Aswathy Ravindran Girija, Bionanotechnology in Cancer, 2023
Among the group of rare earth metals or the lanthanide series, gadolinium (Gd) is a popular choice for magnetic resonance imaging (MRI) T1 contrast agents [140] and also an interesting material to pursue its application in neutron capture therapy (NCT) [141]. Gd-chelates provide precise irradiation when used in MRI-guided radiotherapy and their efficiency as radiosensitizer was reported by Young et al. while using a porphyrin complex of Gd (III) texaphyrin (Gd-tex2+) [142]. The manipulation on the size of GdNP could be advantageous for its excretion by the kidney, which was proved by Mignot et al. who constructed GdNPs (AGuIX) of 5 nm in diameter [143]. Since nonradioactive GdNPs have the capacity of high neutron capture, GdNPs-loaded chitosan NPs were demonstrated to be viable agents for Gd-NCT [144]. GdNPs promise to serve the dual purpose of diagnostic and therapeutic agents in clinical studies and combining the radiosensitizing effects of the GdNPs with X-rays, gamma rays, and charged particles contribute to enhanced killing effects [125, 145]. As discussed earlier regarding the small size of GdNP and its superiority as an MRI contrast agent, Hu et al. exploited these two properties of GdNPs to analyze their uptake and MRI-guided radio sensitization effects in hepatocellular carcinoma cells [142]. MRI imaging demonstrated that the ratio of AGuIX NPs in tumor/liver was the highest after 1 h of i.v. injection and a decrease in tumor size in presence of radiation therapy with AGuIX [146]. Commercially available gadolinium-based molecular agent DOTAREM® was compared with AGuIX NPs to evaluate the efficiency of MRI in healthy animals. AGuIX NPs and DOTAREM® when injected at the same concentrations, AGuIX NPs showed a better contrast than DOTAREM® due to their higher relaxivity and twice higher prolonged circulation in the blood [147]. Despite the availability of state-of-the-art therapeutic strategies, brain metastases have serious neurological and survival repercussions. A recent demonstration on the use of AGuIX NPs as effective theranostic and radiosensitizer agents with favorable toxicity levels has motivated its first use in human study to evaluate maximum tolerable dose in combination with whole-brain radiotherapy (WBRT) (trial registration number NCT02820454) [148]. Multifunctional bismuth gadolinium oxide (BiGdO) surface modified with PEG was constructed to perform a combination of functions like radiotherapy, computed tomography, and MRI. Bismuth and Gd provided CT contrast, while Gd alone is used as an MRI contrast agent, thus the NP served as a dual-modal imaging agent with contrast enhancement [149]. Another stealth GdNPs hyaluronic acid-functionalized Gd-oxide NPs were evaluated for their biocompatibility, radiosensitizing, and MRI agents in tumor cells displaying rapid intracellular uptake by the cancer cells via HA-receptor-mediated endocytosis, low cytotoxicity, high relaxivity as MRI agents, and enhancement in radiosensitivity [150].
Data Augmentation for Improved Brain Tumor Segmentation
Published in IETE Journal of Research, 2023
Ankur Biswas, Paritosh Bhattacharya, Santi P. Maity, Rita Banik
Brain tumor, an assembly of uneven and irregular cells, produced by an unrestrained cell division is extended in and around the brain and is one of the most frequent basis of diseases in people globally [1]. Two main types of tumors exist, the first one is the malignant tumors that are cancerous and the second one is the benign tumors or non-cancerous. Cancerous tumors can be further categorized into the primary tumors that establish within the brain, and the secondary tumors that extend from elsewhere, known as brain metastasis tumors. Malignant tumors often grow with time while a benign tumor initially remains fixed, but if untreated, may turn into cancerous. Hence, it must be detected at its initial stage from the symptoms and need monitoring for growth in size and appearance for the sake of treatment. The primary step to distinguish a brain tumor in magnetic resonance imaging (MRI) demands a perfect segmentation of the tumor, which is the progression to separate the tissues of the tumor from the normal brain tissues. This task is quite challenging since tumors vary in their shape, size, texture as well as appearance [2]. MRI, computed tomography (CT), positron emission tomography (PET), etc. are the different forms of clinical imaging modalities utilized to evaluate brain tumor, out of which MRI is preferably chosen one because of its non-invasive nature and also offers a wide contrast variation of tissues with a high level of resolution and accuracy in the brain. It creates a three-dimensional (3D) image of an anatomical structure that helps to obtain the crucial information for efficient pathologies. Earlier, brain tumors were delineated manually through spotting the different regions of tumor slice-by-slice which was prolonged. Researchers are carrying out multiple studies through modern imaging machinery to completely computerize the conclusion system and lessen the extracting time of costly and precise information to support health practitioners. Hence, segmentation of tumor in 3D is highly demanded and plays an essential role in effective handling of treatment.