| 1. |
- Bardies, Manuel, et al.
(author)
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Quantitative imaging for clinical dosimetry
- 2006
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In: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0167-5087 .- 0168-9002. ; 569:2, s. 467-471
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Journal article (peer-reviewed)abstract
- Patient-specific dosimetry in nuclear medicine is now a legal requirement in many countries throughout the EU for targeted radionuclide therapy (TRT) applications. In order to achieve that goal, an increased level of accuracy in dosimetry procedures is needed. Current research in nuclear medicine dosimetry should not only aim at developing new methods to assess the delivered radiation absorbed dose at the patient level, but also to ensure that the proposed methods can be put into practice in a sufficient number of institutions. A unified dosimetry methodology is required for making clinical outcome comparisons possible.
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| 2. |
- Chittenden, Sarah J., et al.
(author)
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A Phase 1, Open-Label Study of the Biodistribution, Pharmacokinetics, and Dosimetry of Ra-223-Dichloride in Patients with Hormone-Refractory Prostate Cancer and Skeletal Metastases
- 2015
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In: Journal of Nuclear Medicine. - : Society of Nuclear Medicine. - 0161-5505 .- 2159-662X. ; 56:9, s. 1304-1309
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Journal article (peer-reviewed)abstract
- 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 Ra-223-dichloride in patients with bone metastases due to castration-refractory prostate cancer. Methods: Six patients received 2 intravenous injections of Ra-223-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. Safety was assessed from adverse events. Results: The injected activity cleared rapidly from blood, with 1.1% remaining at 24 h. The main route of excretion was via the gut, although no significant toxicity was reported. Most of the administered activity was taken up rapidly into bone (61% at 4 h). The range of absorbed doses delivered to the bone surfaces from a emissions was 2,331-13,118 mGy/MBq. The ranges of absorbed doses delivered to the red marrow were 177-994 and 1-5 mGy/MBq from activity on the bone surfaces and from activity in the blood, respectively. No activity-limiting toxicity was observed at these levels of administration. The absorbed doses from the second treatment were correlated significantly with the first for a combination of the whole body, bone surfaces, kidneys, and liver. Conclusion: A wide range of interpatient absorbed doses was delivered to normal organs. Intrapatient absorbed doses were significantly correlated between the 2 administrations for any given patient. The lack of gastrointestinal toxicity is likely due to the low absorbed doses delivered to the gut wall from the gut contents. The lack of adverse myelotoxicity implies that the absorbed dose delivered from the circulating activity may be a more relevant guide to the potential for marrow toxicity than that due to activity on the bone surfaces.
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| 3. |
- Gear, Jonathan I., et al.
(author)
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EANM practical guidance on uncertainty analysis for molecular radiotherapy absorbed dose calculations
- 2018
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In: European Journal of Nuclear Medicine and Molecular Imaging. - : Springer Science and Business Media LLC. - 1619-7070 .- 1619-7089. ; 45:13, s. 2456-2474
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Journal article (peer-reviewed)abstract
- A framework is proposed for modelling the uncertainty in the measurement processes constituting the dosimetry chain that are involved in internal absorbed dose calculations. The starting point is the basic model for absorbed dose in a site of interest as the product of the cumulated activity and a dose factor. In turn, the cumulated activity is given by the area under a time–activity curve derived from a time sequence of activity values. Each activity value is obtained in terms of a count rate, a calibration factor and a recovery coefficient (a correction for partial volume effects). The method to determine the recovery coefficient and the dose factor, both of which are dependent on the size of the volume of interest (VOI), are described. Consideration is given to propagating estimates of the quantities concerned and their associated uncertainties through the dosimetry chain to obtain an estimate of mean absorbed dose in the VOI and its associated uncertainty. This approach is demonstrated in a clinical example.
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| 4. |
- Giammarile, Francesco, et al.
(author)
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EANM procedure guideline for the treatment of liver cancer and liver metastases with intra-arterial radioactive compounds
- 2011
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In: European Journal of Nuclear Medicine and Molecular Imaging. - : Springer Science and Business Media LLC. - 1619-7070 .- 1619-7089. ; 38:7, s. 1393-1406
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Journal article (peer-reviewed)abstract
- surgery (i.e. resection or liver transplantation), but only 10-20% of patients are candidates for this. In other patients, a variety of palliative treatments can be given, such as chemoembolization, radiofrequency ablation or recentlyPrimary liver cancers (i.e. hepatocellular carcinoma or cholangiocarcinoma) are worldwide some of the most frequent cancers, with rapidly fatal liver failure in a large majority of patients. Curative therapy consists of introduced tyrosine kinase inhibitors, e. g. sorafenib. Colorectal cancer is the second most lethal cancer in Europe and liver metastases are prevalent either at diagnosis or in follow-up. These patients are usually treated by a sequence of surgery, chemotherapy and antibody therapy [Okuda et al. (Cancer 56: 918-928, 1985); Schafer and Sorrell (Lancet 353: 1253-1257, 1999); Leong et al. (Arnold, London, 1999)]. Radioembolization is an innovative therapeutic approach defined as the injection of micron-sized embolic particles loaded with a radioisotope by use of percutaneous intra-arterial techniques. Advantages of the use of these intra-arterial radioactive compounds are the ability to deliver high doses of radiation to small target volumes, the relatively low toxicity profile, the possibility to treat the whole liver including microscopic disease and the feasibility of combination with other therapy modalities. Disadvantages are mainly due to radioprotection constraints mainly for I-131-labelled agents, logistics and the possibility of inadvertent delivery or shunting [Novell et al. (Br J Surg 78: 901-906, 1991)]. The Therapy, Oncology and Dosimetry Committees have worked together in order to revise the European Association of Nuclear Medicine (EANM) guidelines on the use of the radiopharmaceutical I-131-Lipiodol (Lipiocis (R), IBA, Brussels, Belgium) and include the newer medical devices with Y-90-microspheres. Y-90 is either bound to resin (SIR-Spheres (R), Sirtex Medical, Lane Cove, Australia) or embedded in a glass matrix (TheraSphere (R), MDS Nordion, Kanata, ON, Canada). Since Y-90-microspheres are not metabolized, they are not registered as unsealed sources. However, the microspheres are delivered in aqueous solution: radioactive contamination is a concern and microspheres should be handled, like other radiopharmaceuticals, as open sources. The purpose of this guideline is to assist the nuclear medicine physician in treating and managing patients undergoing such treatment. I-131-Lipiodol is a consolidated treatment option and the previous European Association of Nuclear Medicine (EANM) guidelines have been revised for its use. The newer Y-90-microsphere therapy is rapidly expanding throughout the nuclear medicine community. To date, published data on microspheres, particularly on dosimetry features and the characterization of the objective response, are still preliminary. Therefore, the aim of this part of the document is to set up a first basic procedure to guide nuclear medicine physicians in treatment with radiolabelled microspheres.
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| 5. |
- Hindorf, Cecilia, et al.
(author)
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EANM Dosimetry Committee guidelines for bone marrow and whole-body dosimetry
- 2010
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In: European Journal of Nuclear Medicine and Molecular Imaging. - : Springer Science and Business Media LLC. - 1619-7070 .- 1619-7089. ; 37:6, s. 1238-1250
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Journal article (peer-reviewed)abstract
- The level of administered activity in radionuclide therapy is often limited by haematological toxicity resulting from the absorbed dose delivered to the bone marrow. The purpose of these EANM guidelines is to provide advice to scientists and clinicians on data acquisition and data analysis related to bone-marrow and whole-body dosimetry. The guidelines are divided into sections "Data acquisition" and "Data analysis". The Data acquisition section provides advice on the measurements required for accurate dosimetry including blood samples, quantitative imaging and/or whole-body measurements with a single probe. Issues specific to given radiopharmaceuticals are considered. The Data analysis section provides advice on the calculation of absorbed doses to the whole body and the bone marrow. The total absorbed dose to the bone marrow consists of contributions from activity in the bone marrow itself (self-absorbed dose) and the cross-absorbed dose to the bone marrow from activity in bone, larger organs and the remainder of the body. As radionuclide therapy enters an era where patient-specific dosimetry is used to guide treatments, accurate bone-marrow and whole-body dosimetry will become an essential element of treatment planning. We hope that these guidelines will provide a basis for the optimization and standardization of the treatment of cancer with radiopharmaceuticals, which will facilitate single- and multi-centre radionuclide therapy studies.
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| 6. |
- Hindorf, Cecilia, et al.
(author)
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Quantitative imaging of 223Ra-chloride (Alpharadin) for targeted alpha-emitting radionuclide therapy of bone metastases.
- 2012
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In: Nuclear Medicine Communications. - 1473-5628. ; 33:7, s. 726-732
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Journal article (peer-reviewed)abstract
- 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. Less than 2% of the emissions are from photons. This means that a high absorbed dose will be delivered locally, although the number of photons for imaging will be low. The purpose of this study was to investigate the possibility of quantitative imaging of Ra to enable biodistribution studies. METHODS: A Philips Forte gamma camera, equipped with a medium-energy collimator, was used. Basic imaging parameters were determined from phantom studies, and the accuracy of activity quantification was tested in a phantom study and within a patient study. RESULTS: Imaging parameters were determined for the three most suitable photon peaks from the acquired energy spectrum (82, 154 and 270 keV). Camera sensitivity is constant for circular sources with areas greater than 10 cm. The spatial resolution (full-width at half-maximum) was 1.1 cm for each of the three energy windows. The possibility for quantitative imaging was further investigated for the 82 keV energy window, which showed the highest sensitivity and spatial resolution. A phantom study showed that activity could be quantified to within 10% for a 200 ml volume placed within water containing background activity and to within 50% for a 0.5 ml phantom. Quantification of activity in bone after administrations of 100 kBq/kg of Ra-chloride proved the feasibility of quantitative imaging of patients who have received radionuclide therapy. CONCLUSION: Because of the high-energy deposition of Ra, only a low injected activity is required for therapy, which results in a low count rate for the gamma camera. Nevertheless, this study has demonstrated that it is possible to quantify uptake with a sufficient degree of accuracy to obtain clinically relevant information.
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| 7. |
- Hindorf, Cecilia, et al.
(author)
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Single-cell dosimetry for radioimmunotherapy of B-cell lymphoma patients with special reference to leukemic spread
- 2007
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In: Cancer Biotherapy & Radiopharmaceuticals. - : Mary Ann Liebert Inc. - 1557-8852 .- 1084-9785. ; 22:3, s. 357-366
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Journal article (peer-reviewed)abstract
- Aims: Many lymphoma patients have both macroscopic tumors and single-cell manifestations of their disease. Treatment efficacy could, therefore, depend on the radionuclide used. The aim of this study was to investigate dosimetry at a cellular level for three isotopes of radioiodine. Methods: Cells were assumed to be spherical with radii of 6.35, 7.7, and 9.05 mu m corresponding to the dimensions of the Raji cells. The radius of the nucleus was assumed to be 75% of the cellular radius. The electron energies were 18, 28, and 190 keV, corresponding to the mean electron energy per decay for I-125, I-123, and I-131, respectively. S-values for different activity distributions were simulated using Monte Carlo and dose-volume histograms as well as absorbed doses, and absorbed dose rates were calculated. Results: I-125 gives the highest absorbed dose (similar to 4-40 times that of I-131), whereas I-123 Will give the highest absorbed dose rate (similar to 100 times that of I-131). Under the given assumptions, the absorbed dose at this level is more dependent on the Size of the cells than on whether the radioimmunoconjugate is internalized. Conclusions: This enquiry showed that both I-123 and I-125 have greater potential than I-131 for the treatment of leukemic spread in patients With lymphoma.
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| 8. |
- Holstensson, Maria, et al.
(author)
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Optimization of energy-window settings for scatter correction in quantitative In-111 imaging: Comparison of measurements and Monte Carlo simulations
- 2007
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In: Cancer Biotherapy & Radiopharmaceuticals. - : Mary Ann Liebert Inc. - 1557-8852 .- 1084-9785. ; 22:1, s. 136-142
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Journal article (peer-reviewed)abstract
- Activity quantification in nuclear medicine imaging is highly desirable, particularly for dosimetry and biodistribution studies of radiopharmaceuticals. Quantitative In-111 imaging is increasingly important with the current interest in therapy using Y-90 radiolabeled antibodies. One of the major problems in quantification is scatter in the images, which leads to degradation of image quality. The aim of this study was to optimize the energy-window settings for quantitative In-111 imaging with a camera that enabled acquisition in three energy windows. Experimental measurements and Monte Carlo simulations, using the SI-MIND code, were conducted to investigate parameters such as sensitivity, image contrast, and image resolution. Estimated scatter-to-total ratios and distributions, as obtained by the different window settings, were compared with corresponding simulations. Results showed positive agreement between experimental measurements and results from simulations, both quantitatively and qualitatively. We conclude that of the investigated methods, the optimal energy-window setting was two windows centered at 171 and 245 keV, together with a broad scatter window located between the photopeaks.
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| 9. |
- Minguez Gabina, Pablo, et al.
(author)
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Biologically effective dose in fractionated molecular radiotherapy-application to treatment of neuroblastoma with (131)I-mIBG.
- 2016
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In: Physics in Medicine and Biology. - : IOP Publishing. - 1361-6560 .- 0031-9155. ; 61:6, s. 2532-2551
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Journal article (peer-reviewed)abstract
- In this work, the biologically effective dose (BED) is investigated for fractionated molecular radiotherapy (MRT). A formula for the Lea-Catcheside G-factor is derived which takes the possibility of combinations of sub-lethal damage due to radiation from different administrations of activity into account. In contrast to the previous formula, the new G-factor has an explicit dependence on the time interval between administrations. The BED of tumour and liver is analysed in MRT of neuroblastoma with (131)I-mIBG, following a common two-administration protocol with a mass-based activity prescription. A BED analysis is also made for modified schedules, when due to local regulations there is a maximum permitted activity for each administration. Modifications include both the simplistic approach of delivering this maximum permitted activity in each of the two administrations, and also the introduction of additional administrations while maintaining the protocol-prescribed total activity. For the cases studied with additional (i.e. more than two) administrations, BED of tumour and liver decreases at most 12% and 29%, respectively. The decrease in BED of the tumour is however modest compared to the two-administration schedule using the maximum permitted activity, where the decrease compared to the original schedule is 47%.
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| 10. |
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