Vol.:(0123456789) 1 3 Journal of Radioanalytical and Nuclear Chemistry https://doi.org/10.1007/s10967-019-06816-y Appraisement of  186/188 Re‑HEDP, a new compositional radiopharmaceutical Zahra Pourhabib 1  · Hassan Ranjbar 2  · Ali Bahrami Samani 2  · Ali Asghar Shokri 1 Received: 24 June 2019 © Akadémiai Kiadó, Budapest, Hungary 2019 Abstract Undoubtedly radionuclide therapy is the next phase of nuclear medicine development. 188 Re-HEDP and 186 Re-HEDP are therapeutic radiopharmaceuticals which have been used to treat bone metastases. With regard to their complementary features, in this study, as new idea their combined efects have been investigated with preparing the cocktail of 188/186 Re-HEDP with radiochemical purity nearly 99%. The 188/186 Re-HEDP biodistribution was checked in rats’ tissues up to 72 h. The produced 188/186 Re-HEDP properties suggest a new bone palliative radiopharmaceutical to overcome bone metastases. Keywords 186/188 Re-HEDP · Combined radionuclide therapy · Pain palliation · Biodistribution Introduction For more than half a century, radiopharmaceuticals have been used in diagnostics and therapeutics [1]. Radiophar- maceuticals are pharmaceutical formulations comprising of two components (radioisotopes and molecules labeled with radioisotopes), which are used for the diagnostic and thera- peutic applications of various human diseases [2]. Briefy, short-lived radionuclides emitting β + particles (positrons) or γ-rays are employed in diagnosis, whereas in the therapeutic applications particle-emitting radionuclides are utilized. Three general groups of radioisotopes decays have been evaluated for therapeutic potential: alpha-particle emitters, β − particle emitters, and Auger electron and Coster- Kronig electron emitters following electron capture [3, 4]. In general, two main categories must be considered in the therapeutic radionuclide, frst group namely physical properties include: physical half-life, emission type, radia- tion energy(s), daughter product(s), production method and radionuclide purity and the second one biochemical char- acteristics include: targeting the tissues, retaining tumor radioactivity, in vivo stability and toxicity [5]. Beta emitting (β − ) radionuclides with spread tissue pen- etration range and energy have wide therapeutic applications and can be used in treating diferent sized tumors. The depo- sition of their energy in the tissues results in cell damage. The selection of an optimal radionuclide for treat diferent sized tumors depends on features like energy and penetra- tion range. Alpha-emitters and low beta-energy emitters like 186 Re, 177 Lu with low range of radiation are useful in case of direct targeting of tumor cells and small metastases. On the other hand, radionuclides like 90 Y and 166 Ho and 188 Re which have higher β − energies have great tissue penetrations up to multi-millimeter from the source. In bone pain palliation, conjugating bisphosphonates which prefer to uptake at the bone cells, the high energy beta emitters with high crossfre and higher dose to the tumor cells can be more helpful [6]. In radionuclides with short half-lives, the rate of decay is higher and radiation dose delivers to target at once. About radionuclides with long half-lives the tumor is exposed to prolonged radiation dose and as a result postpone the return of the disease [7, 8]. Applying mixed radionuclides with these complementary features can greatly increase efective- ness of treatment. Among radionuclides, rhenium with two medical radio- nuclides 186 Re (T 1/2 : 90 h; E β : 1.07, 0.93 MeV, E γ : 137 keV) and 188 Re (T 1/2 : 17 h; E β : 2.1 MeV, E γ : 155 keV) [9] with diferent and complementary characteristics such as physical half-life and beta energy can be good choice. Especially in bone metastases treatments which there are the widespread * Hassan Ranjbar hranjbar@aeoi.org.ir 1 Department of Physics, Payame Noor University (PNU), P.O. Box 19395-4697, Tehran, Iran 2 Material and Nuclear Fuel Research School, Nuclear Science and Technology Research Institute, Tehran, Iran