The peer-reviewed journal ‘Current Radiopharmaceuticals’ continues to build on its success from the previous ten issues. The journal offers a range of article formats including research articles, reviews, communications, editorial letters and perspectives. The first issue of 2018 contained articles on PET/CT imaging of prostate cancer using the radiotracer 68Ga-PSMA and imaging of childhood neuroblastoma including copper radionuclides. In addition to a discussion on mechanisms of radiation bystander, The ITALIAN trial and imaging non-small cell lung cancer (NSCLC) patients using 18F-FAZA PET/CT. Other topics include quantification of radiation exposure, comparing PET radiopharmaceuticals in Brazil and Belarus, PET renal agents and a letter regarding the International Consensus Radiochemistry Nomenclature Guidelines.
All of these articles have been peer-reviewed by members of the editorial board including guest editors. Here, we would personally like to take this opportunity to thank everyone on the editorial board who have volunteered their time to review the various articles that we have received and the editorial staff at Bentham Science. The journal also compiles thematic ‘Hot Topic’ issues to generate the maximum impact of the published material in that particular subject area of radiopharmaceuticals and nuclear medicine.
The efforts and determination of the editorial board and guest editors have helped promote the journal at various scientific meetings owing to its MEDLINE/PubMed status since 2011.
In this Editorial Review, we have summarised all the abstracts from the first issue of 2018.
The first article of 2018 was on, ‘PET/CT With 68Ga-PSMA in Prostate Cancer: Radiopharmaceutical Background and Clinical Implications’, by Giovacchini et al. This article discusses the application of radiolabelled choline using positron emission tomography/computed tomography (PET/CT) to image prostate cancer. The disadvantage of this approach is the low positive detection rate of the technique for PSA (prostate-specific antigen)< 1ng/ mL and therefore, the author's research into the development of other tracers for imaging prostate cancer. They reviewed 68Ga-PSMA, a receptor ligand tracer, which has been identified as the most promising radiopharmaceutical for imaging prostate cancer. This tracer has a high positive detection rate for the PSA levels < 1 ng/mL. They demonstrated that 68Ga-PSMA detection rate is also sensitive to PSA kinetics. These initial results indicated that 68Ga-PSMA may significantly affect the clinical management of prostate cancer patients. PSMA labelled ligands have shown to be a promising tracer for the diagnosis and treatment of prostate cancer.
In the next article entitled, ‘Review: The Role of Radiolabeled DOTA-Conjugated Peptides for Imaging and Treatment of Childhood Neuroblastoma’, by Alexander et al. In this article the authors reviewed the rationale behind using DOTA-conjugated peptides in imaging and treatment of childhood neuroblastoma. The SPECT radiopharmaceutical is used in the metastatic staging for neuroblastoma including the procedure of relapsed and refractory neuroblastoma. In another approach taking advantage of neuroblastoma tumours that are expressed mostly in somatostatin receptor-2 (SSTR2); the idea is to apply somatostatin analogues including DOTA-conjugated peptides; for example, DOTATATE and DOTATOC. The radiolabelled DOTA-peptides are used routinely in adults to image neuroendocrine tumours. In addition, they have the potential to be used to image and treat neuroblastoma. However, 68Ga-DOTATATE is used in PET-CT imaging because it is more sensitive and produces rapid clearance, including reduced radiation exposure compared to 123I-MIBG. Furthermore, therapeutic studies using peptide receptor radionuclides such as 177Lu-DOTATATE in patients with relapsed neuroblastoma have also used 68Ga-DOTATATE in PET-CT imaging to assess therapy treatment plans. The authors have suggested that further investigations are required to determine the appropriate indications, timings, scoring and clinical significance of radiolabeled DOTA-peptide conjugated PET/CT imaging in childhood neuroblastoma.
The article, ‘Radiopharmaceuticals Labelled with Copper Radionuclides: Clinical Results in Human Beings’, by Follacchio et al. This article aims to provide an overview on the clinical results obtained in human studies by using copper radionuclides. PET imaging uses the radioisotopes of carbon-11, oxygen-15 and nitrogen-13 including the most commonly used radiotracer fluorine-18. The most widely used radiopharmaceutical for tumour imaging is 18F-fluorodeoxyglucose and is consequently a platform for the development of novel radiopharmaceuticals. Interestingly, other PET radionuclides with a more prolonged half-life have been investigated for both imaging and therapeutic purposes. These include the halogens iodine-124, iodine-120 and bromine-76 in addition to several metal radionuclides. The copper radionuclides have also been studied for their diagnostic imaging properties; these include copper-60, copper-61, copper-62 and copper-64. In addition, for their radiotherapeutics use this would include copper-64 and copper-67. The authors have indicated that copper-64 seems to be the most suitable radioisotope for future clinical applications due to its longer half-life of 12.7 hours and its commercial availability. Future clinical applications using copper-67could be used to design a novel theranostics agent.
The following article on, ‘Mechanisms of Radiation Bystander and Non-Targeted Effects: Implications to Radiation Carcinogenesis and Radiotherapy’, by Yahyapour et al. The authors reviewed the effects of ionising radiation with cells and studying the mechanisms involved in cancer induction in non-targeted tissues. The bystander effect used exogenous mediators to migrate to distant tissues and stimulate various signalling pathways. This can lead to changes in immune responses, epigenetic modulations and radiation carcinogenesis. Epigenetic dysfunctions, DNA damage and cell death are responsible for the initiation of several signalling pathways that can finally result in secretion of clastogenic factors. Moreover, studies have shown that damage is caused to both the nucleus and mitochondrial DN; the membranes and some organelles are involved. Oxidized DNA is associated with other cell death factors stimulating the secretion of inflammatory as well as some anti-inflammatory cytokines from the irradiated area. Furthermore, oxidative stress that results in damage to cellular structures including cell membranes can affect the secretion of exosomes and miRNAs.
The next article entitled, ‘Italian Tailored Assessment of Lung Indeterminate Accidental Nodule by Proposing a Segmental PET/Computed Tomography (s-PET/CT): Rationale and Study Design of a Retrospective, Multicenter Trial,’ by Evangelista et al. The ITALIAN (Italian Tailored Assessment of Lung Indeterminate Accidental Nodule) investigation is a retrospective, multicenter trial designed to compare diagnostic information. This data was provided by segmental positron emission tomography (PET)/computed tomography (CT) (s-PET/CT) with those of whole body (wb)-PET/CT in patients with solitary pulmonary nodules (SPN). In addition, to evaluate the impact on radiobiology and the associated costs with the possibility to introduce alternative imaging modalities.
The article entitled, ‘18F-FAZA PET/CT in the Preoperative Evaluation of NSCLC: Comparison with 18F-FDG and Immunohistochemistry’, by Mapelli et al. The aim of this article was to assess the capability of 18F-FAZA PET/CT in the identification of intratumoral hypoxic areas especially in locally advanced non-small cell lung cancer (NSCLC) patients. Further studies were carried out using the radiotracers18F-FAZA PET/CT and18F-FDG PET/CT to help determine a tumour to blood (T/B) and tumour to muscle (T/M) ratios regarding hypoxic fractions of a tumour. The authors concluded that this may be the first article on assessing hypoxia and glucose metabolism compared with immunohistochemistry in patients who are assessed as candidates to surgery for NSCLC.
In the following article on, ‘Quantification of Radiation Exposure of Non-Dominant Index for the Surgeon Performing Sentinel Lymph-Node Removal Procedure’, by Pesteana et al. This investigation aimed to determine and quantify the exposure to radiation of the non-dominant index for the surgeon performing sentinel lymph-node removal. In addition, to determine, if there is an irradiation risk imposed during the surgical procedure. Background: Sentinel-lymph-node scintigraphy is a useful method for accurate staging of different tumours and a helpful tool in personalised therapy for oncological patients. The radiation exposure for surgical staff has been a concern since the sentinel lymph-node detection method was developed. The surgeon received a minimal dose for the non-dominant index. The values that were recorded did not pose any additional concerns or restrictions; the exposure being under the limits and constraints established by regulations and close to the detectability limit of the dosimeter. The procedure is safe regarding radiation protection especially respecting the limitation and optimisation principles.
The next article on, ‘PET Radiopharmaceuticals in Brazil and Belarus: Economic Comparison using the case of 18FDG’, by Brinkevich et al. The production of radiopharmaceuticals, especially the ones used in PET imaging is complex involving a combination of economic and social factors. This is regards to social aspects, that are essential, the economic issues must be considered and altogether these play a crucial role for the implementation and maintenance of production centres around the world, with emphasis for countries which face economic crisis. This article aims to evaluate the above scenario with this study comparing a well-established production centre in Brazil and a new one in Belarus. The Brazilian model for PET radiopharmaceutical productions should be revised to avoid waste and create a new business model for the area of research.
An editorial letter by Coenen et al. entitled, ‘International Consensus Radiochemistry Nomenclature Guidelines, ’brought to the attention of the radiopharmaceutical community that there was incorrect usage of scientific terms and conventions. In 2015, an international working group was set-up to investigate the use of nomenclature in radiopharmaceutical chemistry and included other discipline areas. The outcome of the working group agreed to provide a reference source for nomenclature used in radiopharmaceutical sciences which extended to the clarification on terminologies such as symbols and expressions.
The final article in the first issue of 2018 was entitled, ‘Preliminary Human Radiation Dose Estimates of PET Renal Agents, Para-18F-Fluorohippuric Acid and Ortho-124I-Iodohippuric Acid from Rat Biodistribution Data’, by Cheki et al. The radiotracers para-18F-fluorohippuric acid (18F-PFH) and ortho-124I-iodohippuric acid (124I-OIH) have been identified to conduct renography using positron emission tomography (PET).This research aimed to estimate preliminary human-equivalent internal radiation dosages of 18F-PFH and 124I-OIH utilising the biodistribution data reported in healthy rats. The results from the studies were compared to the absorbed dose data of technetium-99m-mercaptoacetyltriglycine (99mTc-MAG3) from the International Commission on Radiological Protection (ICRP) publication 80. The authors applied the medical internal radiation dose (MIRD) formula to the extrapolated data from rat to humans and projected the absorbed radiation dosages to a variety of organs in human beings. The S-factor was calculated by applying Monte-Carlo N-particle (MCNP) simulation, and the dose prediction indicated that an injection of 18F-PFH or 124I-OIH in humans would result in an estimated effective absorbed dose of 0.09 or 0.1. The authors have suggested that 18F-PFH and 124I-OIH would deliver much safer levels and lower radiation doses to the patients compared to 99mTc-MAG3 and overall this warrants a clinical trial to estimate the radiation doses more accurately.
The journal is gaining pace, and so is its reputation amongst researchers in pharmaceutical (imaging) companies, institutions and universities; all of this will lead to the continued future success of Current Radiopharmaceuticals.