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Radionuclide Selection for Targeted Molecular Radiotherapy
Published in W. P. M. Mayles, A. E. Nahum, J.-C. Rosenwald, Handbook of Radiotherapy Physics, 2021
223Ra has received increasing attention in recent years. Radium is a natural bone seeker that in the form of 223RaCl2 is used to target skeletal metastases (Nilsson et al. 2005). The ALSYMPCA phase III study of patients with progressive castration-resistant metastatic prostate cancer and bone pain showed that 223RaCl2 improved overall survival relative to a placebo (Parker et al. 2013), and the α-emitter is now used extensively.
Dosimetry Applied to Peptide Radionuclide Receptor Therapy
Published in Marco Chinol, Giovanni Paganelli, Radionuclide Peptide Cancer Therapy, 2016
The natural tropism of the radionuclides selected for labeling the therapeutical compounds can be of minor relevance but cannot be neglected. It is always essential to carefully evaluate the chemical quality of the radiopharmaceutical before its administration, and to be aware of the biodistribution of the free radionuclide in case of deconjugation (33,84). In the perspective of myelotoxicity concern, this can be particularly important for bone seeker radionuclides. Considering 90Y, for example, knowledge on the amount of activity in bone is necessary, because the energetic beta rays may irradiate the adjacent marrow. The literature reports bone localization also for free 177Lu, while free 111In is captured by the transferrin in the bloodstream and trapped into the liver. Thus, additional absorbed doses (85–87) have to be taken into account, depending on the percent of labeling and the in vivo stability of the radiocompound (Table 3).
Experimental Radioimmunotherapy and Methods to Increase Therapeutic Efficacy
Published in David M. Goldenberg, Cancer Therapy with Radiolabeled Antibodies, 1995
Several investigators have been looking at a variety of chelates to conjugate 90Y, 186Re, and 67Cu to MoAbs to try to improve the stability.78 Importantly 90Y is known to be a bone seeker. Thus, it has been important to find a stable chelate to prevent bone uptake and bone marrow suppression with 90Y-labeled antibodies.
Transcriptomics for radiation biodosimetry: progress and challenges
Published in International Journal of Radiation Biology, 2023
The majority of work on signature development for radiation biodosimetry has focused on the response to a single acute low linear energy transfer (LET) photon (gamma- or X-ray) exposure. In an actual large-scale radiological or nuclear event, additional factors are likely to produce more complex exposures that may vary with an individual’s location and circumstance. For instance, exposure to radionuclides dispersed by a dirty bomb or power plant accident, or from fallout from an IND, would result in a low dose rate exposure. Such dose protraction may complicate the interpretation of an acute exposure from the prompt radiation of an IND, or may continue past the time of screening if radionuclides are inhaled or ingested. Both dose rate sensitive and insensitive radiation response genes have been identified within a dose rate range of three orders of magnitude (Ghandhi et al. 2015a; Paul et al. 2015). Studies of common fallout radionuclides, water soluble 137Cs, the bone seeker 90Sr, or thyroid specific 131I have revealed complex patterns of gene expression changes dependent on radionuclide, dose, dose rate, and time, which are distinct from gene expression patterns occurring after acute exposure (Paul et al. 2014; Ghandhi et al. 2015b, 2020; Edmondson et al. 2016). Taken together, this work suggests that signatures optimized for acute exposures may not be informative for protracted exposures.
Radionuclide concentrations in medicinal florae and committed effective dose through Ayurvedic medicines
Published in International Journal of Radiation Biology, 2020
S. Monica, Panakal John Jojo, Mayeen Uddin Khandaker
Primordial radionuclides such as 238U, 232Th and 40K are ubiquitous in every constituent of the environment; air, water, soil, food and also in human body. According to the International Food Safety Authorities Network, plants used as food commonly have primordial radionuclides and their progeny (INFOSAN-2011 2011). The medicinal attributes of many plants are found in leaves, roots, barks, flowers and seeds, and used for the remedy against Anemia, Asthma, Bronchitis, Arthritis, Blood circulation, Cough, Cysts, Diabetes, Migraine, Obesity, Chronic Eczema, Ulcers, Rheumatism, Nervous diseases, Madness, Cholera, Piles and Fistula etc. (Mazid et al. 2012). Medicinal plants are administered in their raw form or in formulations such as solutions, tablets or capsules. Undoubtedly, the activity concentrations of primordial radionuclides in herbal formulations would be different than in the raw plants due to the preparation processes. Thus said, the plants used for medicinal purposes are also a source of natural radionuclides to the human body and can cause internal radiation exposure to the internal organs as in the case of food and water (Al-Kharouf et al. 2008). The radiation exposure due to the intake of medicinal plants and herbal preparations could be deleterious in long term uses. Approximately 10–15% of 210Pb and 214Pb ions, 99% of 226Ra and 228Ra, 214 Bi (bone seeker) and 210Po (soluble) reaches blood and/or lung fluid stream and are distributed to the whole body, and exchanged with calcium in the mineral of skeletal tissues thereby making blood, bone and lung critical organs (UNSCEAR 1998; 2000; Cember and Johnson 2009). Since a significant number of people in India are using traditional herbal medicine for the treatment of various diseases and aliments, the study of radionuclide concentration in such plants has great significance, especially at the juncture of two schools of thought that the uptake of radionuclides can harm our body and can also result in radio-resistance as well as detoxification. Therefore, the most important Ayurvedic medicines used in Kerala and their main ingredients were considered for this investigation comprising of radiometric analysis and the effective dose to the persons consuming Ayurvedic medicines for a long period.