The aim of this report is to present a new two-piece thyroid-neck Phantom produced by the concurrent use of epoxy resin and poly(methyl methacrylate) (PMMA: plexiglass) soft tissue equivalent materials. Accordingly, mass attenuation coefficients of the epoxy resin and the plexiglass compounds were obtained from simulation (NIST XCOM 3. 1) and measurements (practical dosimetry) and compared to those related to human soft tissue (ICRU 44). The thyroid-neck Phantom and thyroid gland dimensions were derived from scientific references and the atlas of human anatomy, respectively. The thyroid Phantom was designed by CATIA V5R16 software and produced by the epoxy resin compound by three-dimensional printer. Other organs were designed by ProNest software and made by the plexiglass sheets by CNC laser cutting machine. The mass attenuation coefficients for the epoxy resin (50 keV-20 MeV) and the plexiglass (0-20 MeV) were comparable to human soft tissue (ICRU 44), all with standard relative deviation beneath 5%. In addition, the SPECT images indicated the similarity between human thyroid tissue and its Phantom. In conclusion, this study proves the feasibility and reliability of epoxy resin application in the production of two-piece thyroid-neck Phantom. This Phantom can be applied in the calibration of gamma camera systems, dosimetry and gamma spectrometry in the nuclear medicine field.

Objective To determine the frequency of Phantom limb sensation (PLS) and Phantom limb pain (PLP) in children and young adults suffering landmine-related amputation.Materials & Methods All youths with amputation due to landmine explosions participated in this study. The proportions of patients with Phantom limb sensation/pain, intensity and frequency of pain were reported. Chi square test was used to examine the relationship between variables. Comparison of PLP and PLS between upper and lower amputation was done by unpaired t-test.Results There were 38 male and 3 female with the mean age of 15.8±2.4yr. The mean interval between injury and follow-up was 90.7±39.6 months. Twelve (44.4%) upper limb amputees and 11 (26.8%) lower limb amputees had PLS. Nine (33.3%) upper limb amputees and 7 (17.1%) lower limb amputees experienced PLP. Of 27 upper limb amputees, 6 (14.6%) and among 15 lower limb amputees, 6 (14.6%) had both PLS and PLP. One case suffered amputation of upper and lower limbs and was experiencing PLS and PLP in both parts. PLS had a significant difference between the upper and lower amputated groups.Significant relationship was observed between age of casualty and duration of injury with PLP.Conclusion Phantom limb sensation and pain in young survivors of landmine explosions appear to be common, even years after amputation.

Introduction: The determination of accurate dose distribution is an issue of fundamental importance in radiotherapy, especially with regard to the fact that the human body is a heterogeneous medium. Therefore, the present study aimed to analyze the density and isodose depth profiles of 6 MV beam in a SP34 slab‐wooden dust (pine) ‐SP34 slab (SWS) heterogeneous Phantom.Materials and Methods: The density of SP34 slab, wooden dust of pine, and thoracic region of 10 patients were calculated using computed tomography (CT) images. The depths of isodose lines were measured for 6 MV beam on the CT images of the chest, SP34 slab Phantom, and SWS Phantom. Dose calculation was performed at the depths of 2, 13, and 21 cm in both Phantoms. Furthermore, patient-specific quality assurance (QA) was implemented using both Phantoms.Results: The mean densities of the lung, SP34 slabs, and wooden dust were 0.29, 0.99, and 0.27 gm/cc respectively. The mean depths of different isodose lines in the SWS Phantom were found to be equivalent to those in actual patients. Furthermore, the percentage variation between the planned and measured doses was higher in the SWS Phantom as compared to that in the SP34 Phantom. Furthermore, the percentage variation between the planned and measured doses in patient‐specific QA was higher in the SWS Phantom as compared to that in the SP34 Phantom.Conclusion: As the findings indicated, the density and isodose depth profiles of the SWS Phantom were equivalent to those of the actual thoracic region of human.

Introduction: The Gamma Knife system is designed solely for non-invasive treatment of brain disorders, and it benefits from stereotactic surgical techniques. Dose calculations required in the system are performed by GammaPlan code; in this code, brain tissue is considered uniform. In the present study, we evaluated the effect of Gamma Knife system on the obtained dose through simulating a real human brain Phantom.Materials and Methods: In this study, a Monte Carlo simulation code (MCNPX2.7) was employed to simulate Gamma Knife system. Brain tissue equivalent Snyder Phantom and combinations were considered according to International Commission on Radiological Units (ICRU) -44 report.Results: To ensure accuracy of the simulations, patient’s head was modeled by a spherical water Phantom. At this point, the dosimetry parameters were compared with those obtained by the Monte Carlo code EGS4 and good consistency was observed (less than 7% difference). At the next stage, the above dosimetry parameters were compared with those obtained experimentally by polystyrene Phantom and EDR2 dosimetry film and improved consistency was detected (less than 0.5% difference). Finally, the Snyder Phantom, as the human brain, was simulated. The Full Width at Half Maximum (FWHM) and penumbra decreased by 4.7% and 18%, respectively. Moreover, an isocenter dose reduction of 30-40%, compared to the water Phantom, was noted.Conclusion: The calculation of the real Phantom showed that water and polystyrene could function similarly, while evaluating dosimetry parameters in the Gamma Knife system; thus, water and polystyrene are not appropriate Phantom matters for this purpose.

Annually, many people are irradiated for diagnostic and therapeutic purposes. As-sessment 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.

Percutaneous renal biopsy is the most common method for obtaining renal tissue. In this article, the authors first explained how to make a cheap model of Phantom easily by sheep’, s kidney in a bowl filled with jelly. Then in the attached video, they showed how to find the ideal site (lower pole of kidney) and in real time, traced biopsy needle from jelly surface to kidney concomitant with ultrasound screen.

Introduction: In the present work, the steps of constructing hybrid Phantoms have been studied. Mathematical and voxel Phantoms are two various kinds of computational human body models which used in dose evaluations and estimations. In mathematical Phantoms, organs contour define with mathematical equations and therefore they are not realistic, unlike voxel Phantoms are image-based and more real. In turn, the disadvantage of voxel Phantoms is extreme dependence of organs contour on CT and MRI image contrast. Hybrid Phantoms are more realistic than mathematical Phantoms and more desirable than voxel Phantoms due to their flexibility in the shape and size of organs. In this approach, organs surface is defined with nonuniform rational B-spline (NURBS) surface which is a mathematical technique used in 3D graphics and animations extensively.Methods: Three steps are carried out to generate a hybrid Phantom. (1) Transforming 2D images of human body to 3D model (2) Producing a 3D polygon mesh model of human body and internal organs (3) Creating NURBS. Initially, CT and MRI images for identifying soft and hard tissues are used. Then, two first steps can be constructing with software codes such as 3D-Doctor. For third step, NURBS modeling software can be used such as Rhinoceros.Results: We constructed hybrid Phantoms with real CT and MRI images and the result is the Rhinoceros normal outcome file as *.rhp. It can be used for any size of human body because the size of organs is changeable. This pliability is the effect of NURBS control points which is the most important advantage of hybrid Phantoms.Conclusion: We used advantages of both mathematical and voxel Phantoms in constructing hybrid Phantoms and thus they have the desirable shape and flexibility in organs. We should transform this Phantom to voxel for applying in Monte carlo codes (MCNP). This voxelisation could be performing with MATLAB codes.Furthermore heart and respiratory motions can be simulated with this technique in 4D Phantoms.