Voxel model of a rabbit: assessment of absorbed doses in organs after CT examination performed by two different protocols

2021 ◽  
Author(s):  
M. Mitrovic ◽  
O. Ciraj-Bjelac ◽  
Z. Jovanovic ◽  
N. Krstic ◽  
D. Nikezic ◽  
...  
Keyword(s):  
Ct Examination ◽  
Absorbed Doses ◽  
Voxel Model

A Simple Method for the Evaluation of Internal Doses in Nuclear Medicine

1974 ◽  
Vol 13 (02) ◽  
pp. 193-206
Author(s):  
L. Conte ◽  
L. Mombelli ◽  
A. Vanoli
Keyword(s):  
Nuclear Medicine ◽  
Close Agreement ◽  
Whole Body ◽  
Simple Method ◽  
Rapid Estimation ◽  
Absorbed Doses ◽  
The Mean ◽  
The Individual ◽  
Estimation Of Risk

SummaryWe have put forward a method to be used in the field of nuclear medicine, for calculating internally absorbed doses in patients. The simplicity and flexibility of this method allow one to make a rapid estimation of risk both to the individual and to the population. In order to calculate the absorbed doses we based our procedure on the concept of the mean absorbed fraction, taking into account anatomical and functional variability which is highly important in the calculation of internal doses in children. With this aim in mind we prepared tables which take into consideration anatomical differences and which permit the calculation of the mean absorbed doses in the whole body, in the organs accumulating radioactivity, in the gonads and in the marrow; all this for those radionuclides most widely used in nuclear medicine. By comparing our results with dose obtained from the use of M.I.R.D.'s method it can be seen that when the errors inherent in these types of calculation are taken into account, the results of both methods are in close agreement.

Maisonneuve fracture

2020 ◽  
Vol 99 (2) ◽  
pp. 77-85
Keyword(s):  
Open Reduction ◽  
Lower Leg ◽  
Fracture Dislocation ◽  
Deltoid Ligament ◽  
Ct Reconstruction ◽  
Distal Fibula ◽  
Ct Examination ◽  
Maisonneuve Fracture ◽  
Fibular Fracture ◽  
Wide Range

Introduction: Maisonneuve fracture (MF) is a generally known entity in ankle trauma. However, details about this type of injury can be found only rarely in the literature. For these reasons we have decided to perform a study on MF epidemiology and pathoanatomy. Methods: The group comprised 70 patients (47 men, 23 women), with the mean age of 48 years, who sustained an ankle fracture-dislocation involving the proximal quarter of the fibula. Ankle radiographs in three views and lower leg radiographs in two views were performed in all patients. A total of 59 patients underwent CT examination in three views, including 3D CT reconstruction in 49 of these patients. MRI was performed in 4 patients. Operative treatment was used in 67 patients; open reduction of the distal fibula into the fibular notch was opted for in 54 of them. Results: The highest MF incidence rate was recorded in the 5th decade in the whole group and in men, while in women the peak incidence was in the 6th decade. After the age of 50, the share of women significantly increased. In 64 cases, the fibular fracture was subcapital, and in 6 cases it involved the fibular head. In 24% of the patients, the fibular fracture was seen only in the lateral radiograph of the lower leg. Widening of the tibiofibular clear space was shown by radiographs in 40 cases. Posterior dislocation of the fibula (Bosworth fracture) and tibiofibular diastasis were recorded in 2 cases each. An injury to the anterior and posterior tibiofibular ligaments was found in all 54 patients with open reduction of the distal fibula. A fracture of the medial malleolus was identified in 27 cases (39%) and a complete lesion of the deltoid ligament in 36 cases (51%); in 7 cases (10%) the medial structures were intact. A fracture of the posterior malleolus occurred in 54 (77%) patients. Osteochondral fracture of the talar dome was diagnosed in 2 patients and compression of the articular surface of the distal tibia in the region of the fibular notch in 1 patient. Conclusion: Maisonneuve fracture includes a wide range of injuries both to bone and ligamentous structures of the ankle. Therefore, CT examination is an indispensable part of assessment of this type of fracture.

Hybrid Imaging in Evaluation of Abdominal Sarcoidosis

2018 ◽  
Vol 15 (1) ◽  
pp. 26-31 ◽  
Author(s):  
Isidora Grozdic Milojevic ◽  
Dragana Sobic-Saranovic ◽  
Nebojsa Petrovic ◽  
Slobodanka Beatovic ◽  
Marijana Tadic ◽  
...  
Keyword(s):  
Fdg Pet ◽  
Therapy Response ◽  
Ct Examination ◽  
Abdominal Disease ◽  
Pet Ct ◽  
Fdg Pet Ct ◽  
Total Remission ◽  
Active Disease

Objective: To determine the prevalence of abdominal involvement, distribution pattern and evaluate role of hybrid molecular imaging in patients with abdominal sarcoidosis. Methods: Between January 2010 and December 2011, 98 patients with chronic sarcoidosis and presence of prolonged symptoms or other findings suggestive of active disease were referred to FDG PET/CT examination. Active disease was found in 82 patients, and they all were screened for the presence of abdominal sarcoidosis on FDG PET/CT. All patients also underwent MDCT and assessment of serum ACE level. Follow up FDG PET/CT examination was done 12.3±5.4 months after the baseline. Results: Abdominal sarcoidosis was present in 31/82 patients with active sarcoidosis. FDG uptake was present in: retroperitoneal lymph nodes (77%), liver (26%), spleen (23%), adrenal gland (3%). Majority of patients had more than two locations of disease. Usually thoracic disease was spread into the extrathoracic localizations, while isolated abdominal sarcoidosis was present in 10% of patients. After first FDG PET/CT examination therapy was changed in all patients. Eleven patients came to the follow up examination where SUVmax significantly decreased in the majority of them. Three patients had total remission, three had absence of abdominal disease but discrete findings in thorax and others had less spread disease. ACE levels did not correlate with SUVmax level. Conclusion: FDG PET/CT can be a useful tool for detection of abdominal sarcoidosis and in the evaluation of therapy response in these patients. Awareness of the presence of intra-abdominal sarcoidosis is important in order to prevent long-standing unrecognized disease.

scholarly journals Comparison of 90Y SIRT predicted and delivered absorbed doses using a PSF conversion method

2021 ◽  
Vol 89 ◽  
pp. 1-10
Author(s):  
Allison J. Craig ◽  
Iain Murray ◽  
Ana M. Denis-Bacelar ◽  
Bruno Rojas ◽  
Jonathan I. Gear ◽  
...  
Keyword(s):  
Absorbed Doses ◽  
Conversion Method

Evaluation of age-based radiation dose in paediatric patients received from head CT examination at a tertiary hospital, Nigeria

2021 ◽  
Vol 182 ◽  
pp. 109380
Author(s):  
Muhammad Kabir Abdulkadir ◽  
Iliyasu Yusuf Izge ◽  
Garba Haruna Yunusa ◽  
Abacha Mohammed ◽  
Noor Diyana Osman
Keyword(s):  
Radiation Dose ◽  
Tertiary Hospital ◽  
Head Ct ◽  
Ct Examination ◽  
Paediatric Patients

Line-Based Structure for Voxel Model

2021 ◽  
Author(s):  
Fan Jiangxin ◽  
Jing Shikai ◽  
Che Lei ◽  
Liu Tianren ◽  
Shi Zefang ◽  
...  
Keyword(s):  
Voxel Model

scholarly journals α-Particle-induced DNA damage tracks in peripheral blood mononuclear cells of [223Ra]RaCl2-treated prostate cancer patients

2021 ◽  
Author(s):  
S. Schumann ◽  
U. Eberlein ◽  
C. Lapa ◽  
J. Müller ◽  
S. Serfling ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Dna Damage ◽  
Cancer Patients ◽  
Peripheral Blood Mononuclear Cells ◽  
Peripheral Blood ◽  
Mononuclear Cells ◽  
Absorbed Dose ◽  
Peripheral Blood Mononuclear ◽  
Absorbed Doses ◽  
Blood Mononuclear Cells

Abstract Purpose One therapy option for prostate cancer patients with bone metastases is the use of [223Ra]RaCl2. The α-emitter 223Ra creates DNA damage tracks along α-particle trajectories (α-tracks) in exposed cells that can be revealed by immunofluorescent staining of γ-H2AX+53BP1 DNA double-strand break markers. We investigated the time- and absorbed dose-dependency of the number of α-tracks in peripheral blood mononuclear cells (PBMCs) of patients undergoing their first therapy with [223Ra]RaCl2. Methods Multiple blood samples from nine prostate cancer patients were collected before and after administration of [223Ra]RaCl2, up to 4 weeks after treatment. γ-H2AX- and 53BP1-positive α-tracks were microscopically quantified in isolated and immuno-stained PBMCs. Results The absorbed doses to the blood were less than 6 mGy up to 4 h after administration and maximally 16 mGy in total. Up to 4 h after administration, the α-track frequency was significantly increased relative to baseline and correlated with the absorbed dose to the blood in the dose range < 3 mGy. In most of the late samples (24 h – 4 weeks after administration), the α-track frequency remained elevated. Conclusion The γ-H2AX+53BP1 assay is a potent method for detection of α-particle-induced DNA damages during treatment with or after accidental incorporation of radionuclides even at low absorbed doses. It may serve as a biomarker discriminating α- from β-emitters based on damage geometry.

scholarly journals Radiopharmacokinetic modelling and radiation dose assessment of 223Ra used for treatment of metastatic castration-resistant prostate cancer

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Vera Höllriegl ◽  
Nina Petoussi-Henss ◽  
Kerstin Hürkamp ◽  
Juan Camilo Ocampo Ramos ◽  
Wei Bo Li
Keyword(s):  
Prostate Cancer ◽  
Radiological Protection ◽  
Bolus Administration ◽  
Time Activity ◽  
Biokinetic Model ◽  
Castration Resistant ◽  
Absorbed Doses ◽  
Red Marrow ◽  
Dose Coefficients ◽  
Modelling Study

Abstract Purpose Ra-223 dichloride (223Ra, Xofigo®) is used for treatment of patients suffering from castration-resistant metastatic prostate cancer. The objective of this work was to apply the most recent biokinetic model for radium and its progeny to show their radiopharmacokinetic behaviour. Organ absorbed doses after intravenous injection of 223Ra were estimated and compared to clinical data and data of an earlier modelling study. Methods The most recent systemic biokinetic model of 223Ra and its progeny, developed by the International Commission on Radiological Protection (ICRP), as well as the ICRP human alimentary tract model were applied for the radiopharmacokinetic modelling of Xofigo® biodistribution in patients after bolus administration. Independent kinetics were assumed for the progeny of 223Ra. The time activity curves for 223Ra were modelled and the time integrated activity coefficients, $$ \overset{\sim }{a}\left({r}_S,{T}_D\right), $$ a ~ r S T D , in the source regions for each progeny were determined. For estimating the organ absorbed doses, the Specific Absorbed Fractions (SAF) and dosimetric framework of ICRP were used together with the aforementioned $$ \overset{\sim }{a}\left({r}_S,{T}_D\right) $$ a ~ r S T D values. Results The distribution of 223Ra after injection showed a rapid plasma clearance and a low urinary excretion. Main elimination was via faeces. Bone retention was found to be about 30% at 4 h post-injection. Similar tendencies were observed in clinical trials of other authors. The highest absorbed dose coefficients were found for bone endosteum, liver and red marrow, followed by kidneys and colon. Conclusion The biokinetic modelling of 223Ra and its progeny may help to predict their distributions in patients after administration of Xofigo®. The organ dose coefficients of this work showed some variation to the values reported from clinical studies and an earlier compartmental modelling study. The dose to the bone endosteum was found to be lower by a factor of ca. 3 than previously estimated.

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