Inexpensive human organ phantoms

Journal of Biomedical Physics and Engineering, 2012

Annually, many people are irradiated for diagnostic and therapeutic purposes. Assessment of radiation dose and its related risks to patients are important issues in radiation protection dosimetry. The complex mathematical calculations of the absorbed and effective doses are now done with computers. The calculations are performed with the help of anthropomorphic computational models of human body called phantoms and Monte Carlo codes (MCNP). There are various types of phantoms, yet the latest type is hybrid phantom which has been introduced to the scientific community in recent years. Hybrid phantom is the connection between mathematical and voxel phantoms. They retain both the anatomic realism of voxel phantoms and the flexibility of mathematical phantoms. Using hybrid phantoms, the absorbed doses can be determined for any patients before they are exposed to radiation. Then, the energy of the emitted particles and irradiation geometry can be determined for any special purposes. A hybrid phantom is under construction for Iranian patients to be used in different applications such as testing new radiopharmaceuticals or cancer treatments with high LET radiation. Herein, we report on our findings.

Journal of Ultrasound in Medicine, 1983

2011

The objective this study was to characterize and develop anthropomorphic liver phantoms in tomography hepatic procedures for quality control and improvement professionals in nuclear medicine. For the conformation of the anthropomorphic phantom was used in plaster and acrylic. We constructed three phantoms representing processes with liver cirrhosis. The phantoms were filled with 99mTc diluted with water to obtain the scintigraphic images. Tomography images were analyzed anterior and posterior phantom representing a body with a greater degree cirrhotic. It was noted that the phantoms allow the acquisition of images similar to real liver with cirrhosis. Simulations of hemangiomas may contribute to continued professional education of nuclear medicine, on the question of image acquisition, allowing of the study parameters such of the matrix, energy window and count statistics.

Medical Physics, 2005

Dynamic radionuclide renal study ͑renography͒ provides functional and structural information of the kidney and urinary tract noninvasively. Our purpose in this study is to describe the construction and test results of a dynamic renal phantom with different clinical features of radionuclide renography. The phantom consisted of five pieces of different shaped Plexiglas boxes: Two kidneys, one liver, two square shaped boxes ͑one heart and one bladder͒. The bladder was internally divided into two compartments in order to collect each kidney output separately. The dynamic circulation of the phantom was maintained under a hydrostatic pressure Х13.3 kPa ͑average human blood pressure͒. The standard dose distribution among different organs and different renographic parameters were calculated from series of normal patients study ͑91 with 99m Tc-DTPA, 68 with 99m Tc-EC͒. All the studies were performed with same camera ͑Siemens Orbiter Digitrac 7500͒ equipped with LEAP ͑low energy all purpose͒ collimator using ADAC Pegasys II analytic package program under the same clinical procedure. Different regions of interest ͑ROIs͒ were drawn for concerning organs and counts per second ͑CPS͒ were collected for each ROI. The series of renogram curves were generated by phantom-studies with different flow rates for left kidney ͑LK͒ and right kidney ͑RK͒. The renal index ͑RI͒ for an individual study was calculated as the product of two indexes: "Relative Renal Function" ͑RRF͒ ͑water-volume of LK/RK͒ and "Relative Renal Time" ͑RRT͒ ͑T max of LK/RK͒. The most significant correlation was found in total CPS for LK and RK between the EC group and phantom studies ͑p Ͻ 0.001͒. The calculated RI values were used to simulate the patients' study with different clinical features. The dynamics were found reproducible. The phantom is suitable for using in calibration and quality control protocols of the renogram procedure used in Nuclear Medicine.

Journal of Physics: Conference Series, 2011

A new phantom has been designed that can provide simultaneously different target to background activity ratios with a linearly changing diameter of lesions. The purpose of the study was to describe and perform initial measurements with the phantom aimed to characterize different nuclear medicine tomographic systems and reconstruction algorithms in their performance and behaviour concerning partial volume effect (PVE) and detectability by varying the acquisition parameters and the count statistics. The phantom has an external vessel whose outline is half-cylindrical and allows it to be incorporated into an anthropomorphic thorax phantom. The phantom itself contains 16 fillable cones with an inner diameter linearly decreasing from 16 mm to 2 mm and a wall thickness of 1 mm acrylic glass. They as well as the outer vessel were separately filled with 99m Tc-and 18 F-solutions respectively of different activity concentrations. The phantom was easy to fill and air bubbles could easily be avoided. Images taken using a SPECT/CT and a PET/CT system are presented as well as evaluations of PVE. The new phantom seems to be useful for comparison and optimisation of different acquisition and reconstruction parameters in nuclear medicine tomographic studies and for comparisons between various tomographic units.

Academia Oncology, 2024

Anti-androgen agents such as bicalutamide and enzalutamide, and their modern analogues, are extremely useful agents for prostate cancer therapy and patients initially respond well. With prolonged use, patients will inevitably acquire resistance, at which time therapeutic options become limited. LNCaP cells are extremely useful in investigating AR activity and in modelling disease as they have mutant AR and develop clinically representative resistance mechanisms beyond AR mutation. They are inherently sensitive to bicalutamide and enzalutamide but acquire resistance at prolonged exposure. Here we investigated how LNCaP cells can acquire resistance to bicalutamide and how it may influence enzalutamide resistance.We grew LNCaP cells in 20M bicalutamide continuously, until they grew normally in culture and analyzed differential gene expression for pathways which could help explain the adaptive response to prolonged bicalutamide exposure, via RNA-seq. Using KEGG taxonomy analysis we found that pathways involved in drug efflux and detoxification were upregulated, as well as some intratumoural steroid synthetic pathways. However, we also observed that enzymes normally involved in removing and metabolizing androgens by glucuronide conjugation were strongly downregulated with bicalutamide resistance - namely the UGT2B15 & UGT2B17 enzymes. Utilizing online datasets for further analysis we determined that the UGT2B15 & 17 enzymes were downregulated in several studies of bicalutamide and enzalutamide resistance in LNCaP, VCaP and several other cell lines in in vitro studies. Here we show that these genes, previously linked to androgen independence, have an additional role in the acquired resistance to bicalutamide. We hypothesise that in addition to drug detoxification, androgen antagonist activity could be diminished due to increased competitiveness from higher levels of intracellular androgens, due to increased biosynthesis and decreased androgen metabolism. Androgen salvage could therefore be an additional mechanism for androgen antagonist resistance.

En: Mariano Cornejo (Edit). Uturuncos: un itinerario desde el Cerro de Los Felinos. Córdoba, Argentina: Mundo Editorial., 2023

Breve revisión de las representaciones de jaguares en diversas culturas mesoamericanas, su simbolismo y su significado desde el Preclásico hasra el periodo colonial y aún en algunas fiestas y ceremonias contemporáneas. Se trata luego de encontrar paralelismos y semejanzas con las representaciones gráfico rupestres del Cerro de los Felinos, en el sistema Huaka Yaku, en la Provincia de Salta, en el Noroeste argentino.

During September and October 2012 archaeological excavations reopened in the prehistoric complex of Monte Baranta (Olmedo-SS), under license to Alberto Moravetti (University of Sassari). The archaeological site of Monte Baranta was partially explored in the years 1979-81 and materials found dated the construction of the complex to the Copper Age (Culture of Monte Claro). In the 2012 campaign have been explored five of the six small huts of the village, while the sixth (hut no. 2), entirely excavated in previous campaigns, has been the object of limited tests outside. In the hut 1, current excavation has brought to light a floor of rough stones of medium and small size, in which is embedded a small quadrangular stone structure, perhaps a hearth (?).The hut 3, also quadrangular, had a similar hearth made on the floor, and another elliptical structure realized with orthostatic stones partially sunken in a central area of the hut (a grave?). The hut 4, only partially preserved, also shows the presence of a small quadrangular structure of stones sunken below the floor level. The huts 5 and 6, contiguous, showed the presence of a pavement stones arranged with a certain care; in the hut 6 is present a probable posthole in a central position, while in the hut 5 has been brought to light the usual quadrangular stone structure sunken below the floor level. The materials found have confirmed the chronology of the structures in the Monte Claro period, while there are no traces of post-Chalcolithic phases.

Università degli Studi di Firenze, 19-21 giugno, 2024