SOLLID - a single centre study to develop methods to investigate the effects of low radiation doses within nuclear medicine, to enable multicentre epidemiological investigations.

There is continuing debate concerning the risks of secondary malignancies from low levels of radiation exposure. The current model used for radiation protection is predicated on the assumption that even very low levels of exposure may entail risk. This has profound implications for medical procedures involving ionising radiation as radiation doses must be carefully monitored, and for diagnostic procedures are minimised as far as possible.

Standardised quantitative radioiodine SPECT/CT Imaging for multicentre dosimetry trials in molecular radiotherapy.

The SEL-I-METRY trial (EudraCT No 2015-002269-47) is the first multicentre trial to investigate the role of I and I SPECT/CT-based tumour dosimetry to predict response to radioiodine therapy. Standardised dosimetry methodology is essential to provide a robust evidence-base for absorbed dose-response thresholds for molecular radiotherapy (MRT). In this paper a practical standardised protocol is used to establish the first network of centres with consistent methods of radioiodine activity quantification.

Compartmental Model for Ra-Dichloride in Patients With Metastatic Bone Disease From Castration-Resistant Prostate Cancer.

Purpose: Ra-Dichloride is used for treatment of patients with metastatic bone disease from castration-resistant prostate cancer. The uptake and mechanism of action of Ra-Dichloride is not well understood. The aim of this work was to develop a compartmental model for Ra-Dichloride in patients to improve understanding of the underlying mechanisms.

Improving Transitional Care: The Role of Handoffs and Discharge Checklists in Hematologic Malignancies.

Background: Transitional care from inpatient to outpatient settings is a high-risk time for medical errors and missed follow-up appointments. Discharge checklists and handoffs are effective tools that lead to improved quality of care and outcomes.

Objectives: The purpose of this project was to implement an evidence-based discharge checklist and handoff template to improve and standardize transitional care from hospital to home for patients with hematologic malignancies.

Dosimetry-based treatment for Graves' disease.

Objective: The aim of this retrospective study was to assess the long-term outcome of a personalized dosimetry approach in Graves' disease aiming to render patients euthyroid from a planned thyroid absorbed dose of 60 Gy.

Patients And Methods: A total of 284 patients with Graves' disease were followed prospectively following administration of radioiodine calculated to deliver an absorbed dose of 60 Gy. Patients with cardiac disease were excluded.

Bone lesion absorbed dose profiles in patients with metastatic prostate cancer treated with molecular radiotherapy.

Objective: The aim of this study was to calculate the range of absorbed doses that could potentially be delivered by a variety of radiopharmaceuticals and typical fixed administered activities used for bone pain palliation in a cohort of patients with metastatic castration-resistant prostate cancer (mCRPC). The methodology for the extrapolation of the biodistribution, pharmacokinetics and absorbed doses from a given to an alternative radiopharmaceutical is presented.

Methods: Sequential single photon emission CT images from 22 patients treated with 5 GBq of Re-HEDP were used to extrapolate the time-activity curves for various radiopharmaceuticals.

Excretion and whole-body retention of radium-223 dichloride administered for the treatment of bone metastases from castration resistant prostate cancer.

Objective: The aim of the study was to determine the fraction of administered activity that was excreted and retained by a small cohort of patients who each received treatment with radium-223 dichloride (Ra). Ra is an α-emitting radionuclide that has been approved for use in the treatment of bone metastases that are secondary to castration resistant prostate cancer.

Patients And Methods: Six patients received two weight-based administrations of Ra 6 weeks apart.

The potential of Ra and F-fluoride imaging to predict bone lesion response to treatment with Ra-dichloride in castration-resistant prostate cancer.

Purpose: The aims of this study were to calculate bone lesion absorbed doses resulting from a weight-based administration of Ra-dichloride, to assess the relationship between those doses and corresponding F-fluoride uptake and to assess the potential of quantitative F-fluoride imaging to predict response to treatment.

Methods: Five patients received two intravenous injections of Ra-dichloride, 6 weeks apart, at 110 kBq/kg whole-body weight. The biodistribution of Ra in metastatic lesions as a function of time after administration as well as associated lesion dosimetry were determined from serial Ra scans.

A radiobiological model of metastatic burden reduction for molecular radiotherapy: application to patients with bone metastases.

Skeletal tumour burden is a biomarker of prognosis and survival in cancer patients. This study proposes a novel method based on the linear quadratic model to predict the reduction in metastatic tumour burden as a function of the absorbed doses delivered from molecular radiotherapy treatments. The range of absorbed doses necessary to eradicate all the bone lesions and to reduce the metastatic burden was investigated in a cohort of 22 patients with bone metastases from castration-resistant prostate cancer.

InfuShield: a shielded enclosure for administering therapeutic radioisotope treatments using standard syringe pumps.

The administration of radionuclide therapies presents significant radiation protection challenges. The aim of this work was to develop a delivery system for intravenous radioisotope therapies to substantially moderate radiation exposures to staff and operators. A novel device (InfuShield) was designed and tested before being used clinically.

Phase I/II trials of Re-HEDP in metastatic castration-resistant prostate cancer: post-hoc analysis of the impact of administered activity and dosimetry on survival.

Purpose: To investigate the role of patient-specific dosimetry as a predictive marker of survival and as a potential tool for individualised molecular radiotherapy treatment planning of bone metastases from castration-resistant prostate cancer, and to assess whether higher administered levels of activity are associated with a survival benefit.

Methods: Clinical data from 57 patients who received 2.5-5.

Individualized 131I-mIBG therapy in the management of refractory and relapsed neuroblastoma.

Objective: Iodine-131-labelled meta-iodobenzylguanidine (I-mIBG) therapy is an established treatment modality for relapsed/refractory neuroblastoma, most frequently administered according to fixed or weight-based criteria. We evaluate response and toxicity following a dosimetry-based, individualized approach.

Materials And Methods: A review of 44 treatments in 25 patients treated with I-mIBG therapy was performed.

A Phase 1, Open-Label Study of the Biodistribution, Pharmacokinetics, and Dosimetry of 223Ra-Dichloride in Patients with Hormone-Refractory Prostate Cancer and Skeletal Metastases.

Unlabelled: The aim of this single-site, open-label clinical trial was to determine the biodistribution, pharmacokinetics, absorbed doses, and safety from 2 sequential weight-based administrations of (223)Ra-dichloride in patients with bone metastases due to castration-refractory prostate cancer.

Methods: Six patients received 2 intravenous injections of (223)Ra-dichloride, 6 wk apart, at 100 kBq/kg of whole-body weight. The pharmacokinetics and biodistribution as a function of time were determined, and dosimetry was performed for a range of organs including bone surfaces, red marrow, kidneys, gut, and whole body using scintigraphic imaging; external counting; and blood, fecal, and urine collection.

Patient-specific dosimetry for intracavitary 32P-chromic phosphate colloid therapy of cystic brain tumours.

Purpose: (32)P-chromic phosphate colloid treatments of astrocytoma and craniopharyngioma cystic brain tumours in paediatric patients are conventionally based on a sphere model under the assumption of uniform uptake. The aims of this study were to determine the distribution of the absorbed dose delivered by (32)P on a patient-specific basis and to evaluate the accuracy with which this can be predicted from a pretherapy administration of (99m)Tc-Sn colloid.

Methods: Three patients were treated with (32)P-chromic phosphate colloid following (99m)Tc-Sn colloid administrations.

Quantitative imaging of 223Ra-chloride (Alpharadin) for targeted alpha-emitting radionuclide therapy of bone metastases.

Objective: Ra is an alpha particle emitter that targets areas of increased bone turnover in bone metastases. Alpha particles account for 95% of the 27.8 MeV emitted per decay.

A dose-effect correlation for radioiodine ablation in differentiated thyroid cancer.

Purpose: The aim of this study was to determine the range of absorbed doses delivered to thyroid remnants, blood, and red marrow from fixed administrations of radioiodine and to ascertain whether the success of ablation is more dependent on these absorbed doses than on the administered activity.

Methods: Twenty-three patients received 3,000 MBq radioiodine following near-total thyroidectomy. The maximum absorbed dose to remnants was calculated from subsequent single photon emission tomography scans.

Whole-body dosimetry for individualized treatment planning of 131I-MIBG radionuclide therapy for neuroblastoma.

Unlabelled: The aims of this study were to examine the relationship between whole-body absorbed dose and hematologic toxicity and to assess the most accurate method of delivering a prescribed whole-body absorbed dose in (131)I-metaiodobenzylguanidine ((131)I-MIBG) therapy for neuroblastoma.

Methods: A total of 20 children (1-12 y), 5 adolescents (13-17 y), and 1 adult (20 y) with stage 3 or 4 neuroblastoma were treated to a prescribed whole-body absorbed dose, which in most cases was 2 Gy. Forty-eight administrations of (131)I-MIBG were given to the 26 patients, ranging in activity from 1,759 to 32,871 MBq.

Dosimetry for (90)Y-DOTATOC therapies in patients with neuroendocrine tumors.

The aim of this study was to determine the inter- and intrapatient variability of absorbed dose to the whole body, kidneys, and tumor, as well as the question of whether the first therapy could serve as a guide for future therapies. Fifty (50) (90)Y-DOTATOC therapies were given to 30 patients diagnosed with refractory stage IV neuroendocrine tumors (20 patients received two therapies, 10 patients received one therapy). The first and second therapies were delivered at standard intervals.

Tumor dosimetry on SPECT (186)Re-HEDP scans: variations in the results from the reconstruction methods used.

The aim of this work was to estimate tumor-absorbed doses delivered from the administration of fixed activities of (186)Re-HEDP for the treatment of bone metastases from prostate cancer. The variations and reproducibility in the estimated absorbed dose owing to the reconstruction algorithm used (OSEM vs. FBP) were also analysed.

Dosimetry for fractionated (131)I-mIBG therapies in patients with primary resistant high-risk neuroblastoma: preliminary results.

This paper describes the development of a protocol for SPECT-based tumor dosimetry for (131)I-mIBG therapy patients with high-risk neuroblastoma. The treatment aims to deliver a whole-body dose of 4 Gy in two fractions. Whole-body retention measurements taken during the first fraction are used to guide the second therapy administration.

Optimization of equipment and methodology for whole body activity retention measurements in children undergoing targeted radionuclide therapy.

Accurate measurements of whole-body activity retention of patients during radionuclide therapy are essential for two reasons: First, they enable the correct radiation protection advice to be given and second, they permit the accurate determination of the absorbed whole-body dose delivered during therapy. This, in turn, allows treatment planning to be carried out for future radionuclide therapy on an individual patient basis, and also enables the investigation of the potential correlation of absorbed dose with treatment outcome in groups of patients. There are significant difficulties associated with taking whole-body retention measurements of children, especially when they are very young and/or unwell.

Preparation and use of 131I magic gel as a dosimeter for targeted radionuclide therapy.

Clinical interest in targeted radiotherapy is increasing, but accurate dosimetry studies are difficult to achieve. The aim of this study was to investigate the preparation and use of a "normoxic" polymer gel (with a tissue-equivalent density), known as MAGIC gel, and magnetic resonance imaging (MRI) for nonsealed source dosimetry. MAGIC gel samples were mixed with deionized water (MAGIC95) or a solution of 131I (131I-MAGIC95).

Whole-body dosimetry for targeted radionuclide therapy using spectral analysis.

The whole-body dose (WBD) is routinely calculated for targeted radionuclide therapy (TRT). The aim of this work was to investigate the feasibility of using spectral analysis (SA) for the automatic delineation of decay phases, and consequently, the calculation of the WBD given a whole-body (WB) time-activity curve (TAC). SA characterizes the TAC as an arbitrary sum of exponential functions determined by fitting the data with a non-negative least-squares (NNLS) algorithm.

A model-based method for the prediction of whole-body absorbed dose and bone marrow toxicity for 186Re-HEDP treatment of skeletal metastases from prostate cancer.

In high-activity rhenium-186 hydroxyethylidene diphosphonate ((186)Re-HEDP) treatment of bone metastatic disease from prostate cancer the dose-limiting factor is haematological toxicity. In this study, we examined the correlation of the injected activity and the whole-body absorbed dose with treatment toxicity and response. Since the best response is likely to be related to the maximum possible injected activity limited by the whole-body absorbed dose, the relationship between pre-therapy biochemical and physiological parameters and the whole-body absorbed dose was studied to derive an algorithm to predict the whole-body absorbed dose prior to injection of the radionuclide.