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Questions related to Medical Physics
It is essential for projection radiography and mammography machines to undergo quality control checks or testing to ensure the machines are operating acceptably and optimally. The tests could be subjective or objective. Objective tests can include modulation transfer function, noise power spectrum, and detective quantum efficiency. Can any explain in a simple way the modulation transfer function, noise power spectrum, and detective quantum efficiency? If you have references, kindly please provide. Thank you!
Hi,
I would be grateful if anyone could help me to know about conferences on biomedical engineering (Biotechnology, Bioinformatics, medical physics ... )
Thank you,
Greetings!
I am new to x-ray radiology, and working on a project where I am supposed to compute the thickness of the subject being examined. I found a technical paper published by Fuji inc. ("Improvement in Image Quality and Workflow of X-Ray Examinations using a New Image Processing Method, Virtual Grid Technology"), where it is shown that the thickness can be calculated using the x-ray dose absorbance (figure 5 of the paper). My idea is to apply the Beer-Lambert law on 2D images that I capture before-and-after placing the subject; and to solve the natural logarithm at each corresponding pixel location to obtain a 2D thickness image. I would be very grateful if you could advise whether this is the correct way of computing the thickness. Thank you in advance!!
Brain Tumor Imaging Protocol will reduce variability and increase accuracy in determining progression and response of investigational therapies.
In the pictures below, with the FFT and DFT methods and the PCA phase recovery, which is common in optical microscopes, I obtained the magnetic resonance imaging (MRI) phase of the human brain tumor and the phase obtained.
Can the process be performed on MRI without prescribing Jumpstarting Drugs (JBTDDC)?
Hi, has somebody the IPEM report no 32 part 7: Measurement of the Performance Characteristics of Diagnostic X - Ray Systems, Digital Imaging Systems in PDF. I would be very grateful if somebody could suggest where I can find this report?
As all the world is busy in discovering cure for COVID-19, so why not radiation? COVID-19 has been reported to effect the human's lungs and liver (specific tissues), So, what if those parts are exposed to radiation for the rapid recovery of the patients? Is it possible? Or, is there any possibility for radiotherapy of COVID-19?
Positron emission tomography generally shows imaging of the physiology of the tumor as well as its anatomy, which is superior. It is unique compared to other cross-sectional imaging such as computed tomography or computed tomography (CT) or computed tomography. CT scans or MRIs often can not detect changes at the cellular level if the PET scan is capable of immediate changes. Identify in patient cells.
In order to image the tumor using PET or other methods, differences in basic features established in physiological and Metabolic of tumors and normal tissues. These differences include tumor surface antigens compared to cell tissues. Generally grow and DNA precursors such as thymidine and the rate of protein synthesis in tumors often increase compared to normal tissues. transport and Mixing of various amino acids, as well as anaerobic and aerobic glucose levels, are observed in tumor cells. In a wide range of Tumor types Glucose intake increases significantly compared to healthy tissues. In a typical PET system they are separated by a lead or tungsten blade detection of random photons in one shot Match with photons detected in other shots. In the diagram below, I plotted the average positron emitted energy from several desired radionuclides. Which of these radionuclides is best for our purposes?
I am asking about the effectiveness and accuracy of using the film badge dosemeters to record and measure the exposure for the medical staff nowadays as it is a very old way, but it cost nothing to make such a system for developing the films and read it by a densitometer
and the only guidelines that I have to implement such a system is the (IAEA) Safety series NO.8 Vienna 1962 but it is a very old one and can't get any other new versions or similar guidelines, so is there any such recent guidelines
Or anything related with shielding materials and dosimetry for medical application. I need topics that can be researched on and suitable for undergraduate research work.
Thank you.
Hi everyone
Could you share your research and/ or other researches related to the application of magnetic fields in biophysics and Medical physics?
Thanks
Dear Sirs,
I did not find this material on the internet. There are only mechanical models of some aspects of self-replication. Full mechanical model is absent. Of course it is enourmous problem if one precisely build it. But maybe there are simple and simultaneously more complete mechanical models? I prefer purely mechanical self-replicating machine but self-replicating robots are also good.
I am currently developing a mammography phantom that has an MTF edge portion. The MTF portion is used to test the resolution of the digital mammography unit. My MTF is made of stainless steel with a thickness of 0.8mm and a dimension of 40mm x 40mm.
After exposing the phantom, I have an image of the MTF (a square object with very high attenuation compared to the background). I don't know what the next step is, analyze it or determine the MTF from that image. I just know that you need to put the ROI between the edge and the background. Is there a way I can manually determine the MTF edge of the system? Can you provide me an article or steps on how to do so. Or do I really need software to do determine the MTF? What software can I use to determine the MTF edge? Can you suggest software and the steps on how to determine the MTF from that software.
My alternative way of measuring the MTF of the system is to use a high attenuating material and bar pattern materials. So this MTF is made of a copper sheet (0.2-mm thick), a copper wire that forms 2lp/mm and 4lp/mm, and a transparent area (PMMA). I got this from IEC, and the method of determining the MTF is easy. But this kind of configuration is not used in any commercialized mammography phantom. Most commercialized mammography phantoms used MTF edge. That's why I prefer the 1st MTF configuration.
Do you know the difference between MTF edge and MTF bar pattern?
I really appreciate any help you can provide. Thank you!
Since technology has seemed to extensively pervade virtually every facet of medicine, do you feel that students of medicine (MD or MBBS) should be better equipped with knowledge and skills in mathematics, physics, biomedical image processing (to better process medical images for diagnostics and surgical planning), biomedical signal processing (for better analysis of bioelectrical signals, e.g. EEG, EKG, EMG), and basic computer science?
Care to discuss?
What is the logic or significance for using the inverse square factor for calibration of in vivo dosimeters (placed on surface) to the dose measured by ion chamber at dmax?
Hi i am a Medical Physics PhD student, im interested in Radiolysis and production of free radicals, i am very curious is to collect information is there any possibility to measure the free radicals, singlet oxygen in vivo and vitro. My idea is to measure the spectral changes.I would appreciate suggestions or possibilities if any.
Hi
I am trying to calculate PDD using Geant4
I divided a water phantom to voxels (2 mm x 2mm x 2 mm) by G4NestedParameterisation and i have created a class derived from Sensitive Detector class using Hit (I am not sure that this sensitive detector must be used)
How can I calculate the dose at each voxel?
I am working on Ultrasound Contrast Micro bubbles. I am from Medical background with little Knowledge of Medical Physics. kindly Guide me to some book or video lectures regarding Theoretical Models for estimation of Bubble dynamics ....
I am using Eclipse Treatment System (Version 13.6) on VARIAN CLINAC and I want to know what are the principal differences between another planning systems using the same lineal accelerator.
I want to know what are the differences in the commissioning in the same LINAC.
Is there a significant differences? Is the same?
I am modelling a Phototopic eye system, which includes five wavelengths with different weights, in Zemax.
This system should have defocus of -0.5 diopter (D).
I want to know in a multi-wave system how the defocus is calculated?
Defocus is the average defocus of all five wavelengths?
Or
Defocus is the weighted average defocus of these five wavelengths (weighted based on the weight of the waves)?
Or
Defocus is calculated in a reference wavelength for example 555 nm?
Thanks.
I have been trying to download this dataset for a few weeks now but the download consistently crashes. USC's servers seem to be very slow and the download is trickling at best. Even downloading the data in 5 or 10 file segments, it crashes.
Is there any other website where this data is downloadable from?
In telecommunications, a transmission system is a system which transmits a signal from one place to another. The signal can be an electrical, optical or radio signal.
Can we consider some of the human body systems as transmission systems and then model it using telecommunications' concepts for better understanding?
If we do, can someone please provides some examples of these systems and determines their basic elements(message, transmitter, medium and receiver)?
I am Ph.D. student in medical physics. My research topic entitled (assessment of fetal biometry in low-risk pregnant).
I adopted a cross-sectional design in this study. Please I have several questions about my study and hope to find feedback from you.
- Regarding the sample technique I would like to know what is the most appropriate technique for my study? What I did in this regard, the pregnant come to their appointments randomly and the one who meets the criteria of this study would be participated after getting their consent.
- How can I apply the validity and reliability in this study?
Does Dmax (Depth of dose maximum) depend on chamber? If we measured Dmax (Depth of dose maximum)using cylindrical chamber for specific electron energy (10 MeV) with field size (10x10) and then using parallel plate chamber, does Dmax differ?
Would be possible to implant a prostate PC-3 tumor cell in a gluteus of a mice (or rat) so that it will grow somewhat laterally respect to the animal normal contour?
If that would be possible, a Radiotherapy 6 MV highly collimated single beam could hit the tumor (of about 1 cm3 size) but not vital organs of the animal. If that would be a wrong way, is there a better localization of the tumor Xenograft to obtain the desired result ? Thanks in advance for the help!
Hi all,
I'm trying to simulate the photon decay spectrum of Eu155 in Geant4. I'm not using the decay file provided by Geant4 because the energies and intensities listed are incorrect. I've changed/added values to match trusted literature, ensuring that the syntax is the same and the intensity column sums to 100.
The resulting spectra however is not right. There are too few photons per decay for most energies. I'm confident I'm collecting all the photons. I've attached my decay file and the resulting plot. The picture also has a 2nd plot of what the spectra should approximately look like for comparison.
I want to know what the intensity column is actually doing and how to adjust it such that the photons per decay match the values I've placed in the intensity column (noting that it's as a percentage there).
Any help is greatly appreciated
Thanks,
- Giuseppe
I know how to calculate the MU time but not sure how to get the cumulative dose. I have gone through the Radiation Physics book by Faiz. However no clear cut approach is shown for getting the cumulative dose? So my question is 1) Is there any approach by which cumulative dose can be calculated? or it is prescribed by the radiologist? 2) Do we need to optimize the dose distribution for telecobalt therapy?
Hello
I am working on a DICOM file generated using a medical CT scanner (GE Brightspeed 16). I need to know what is the point spread function of this CT scanner. What information do I need to determine the PSF? can anyone help?
Mohammad
In order to protect the patients and workers, How to deal with a radioactive emergency in the first instant
ICRP-118-2011) Published new version decreased dose limit for occupational workers from 150 mSv to 20 mSv but i did not find any publication concerning any change in eye lens dose limit for public.
Hello, I wanted to know what is wrong with my CT (CAT scan) image. when I do medical imaging everything look normal and clear but after Multi Planar Reformation picture in sagittal and coronal part have low resolution. How can I resolve this problem? do you have any suggestion? thank you
I need this book or any recent copy of it, or any reference have the relation of calculating the absorbed gamma dose (D= Γ x A /d2) or any other dose.
the book: F. H. Attix, "Introduction to Radiological Physics and Radiation Dosimetry," New York, John Willy & Sons, (1986).
impact CT patient DOSIMETRY CALCULATOR software
This is a link to the instrument in question:
J Trauma. 2001 Oct;51(4):740-6.
Development of a brief version of the Burn Specific Health Scale (BSHS-B).
Kildal M1, Andersson G, Fugl-Meyer AR, Lannerstam K, Gerdin B.
Author information
1
Burn Unit, Department of Plastic Surgery, University Hospital, Uppsala, Sweden
PDD is one of the important parameters in dose assessment at a given point. I want to know is there any way to assess this parameter using MCNPx code? Is there any tally or command helping to calculate this parameter?
I need to perform Monte Carlo simulations of a imaging device (dental) with static anode x-ray tube. Can you provide me one or point out a reference/paper/article? Thanks in advance!
Is the risk of necrosis on the helix cartilage of the auricle high? With 50 Gy in 20 fractions and electrons?
As you know that IMRT is delivered with multi-leaf collimators (MLCs). However, the use of MLCs is not mandatory.
Can potentially deliver IMRT plans with the use of collimator jaws?
Is anyone here? doing Jaws s only IMRT
Hi,
I'm looking for a tool able to extract a single slice from a 3D DICOM volume and save it in DICOM format in order to be loaded by the QUART DVT_TEC v2.5.1 analysis software. Someone who know if exist something like that? Also an ImageJ macro will be ok.
Thanks a lot!
I am working with MCNP. The set-up is simply trying to carry out a radiotherapy simulation where I can use a point source of gamma photons to destroy cancerous cells.
My Problem: I am losing particles so the run is terminated.
Geometry: A cylinder is the skull in it there is a sphere>>>Tumor. I put them into a big rectangular box. My point source is another sphere inside the box.
I need help. Am I going the right way?
Dear Dr. Sheikh-Bagheri
Greetings and respect
I am a medical physics PhD student from Iran.I have questions about .3ddose Files from DOSXYZnrc.
My question is how can I 35 different *.3ddose files (about 35 segments in IMRT) will be together and convert it to a Single *.3ddose file. I respectfully ask you to guide me in solving this problem. I am waiting for your mail.
Sincerely
i want use the tld with rando phanton in the chest and abdomen
Hello!
I am a field physicist and I perform QA measurements of various types of X-ray units. Due to recent changes in legal requirements in my country, we have to provide the radiation output value for each unit/tube measured (in mGy/mA.s at 1 meter from focal spot) at filtration of 2,5 mm Al equivalent. This unfortunately cannot be directly achieved for interventional radiology units, some CTs and occasionally other types of X-ray inits.
My question is: how can one calculate the dose at filtration of 2.5 mm Al equivalent from the measured dose at other filtration, assuming HF generators and 0% ripple?
For example: GE Innova 2100 interventional radiography unit, dose rate at 83 kVp and 165,5 mA (single shot) is 14,47 mGy/s and total filtration is 8,33 mm Al equivalent (actual filtration is combination of Al and Cu filters, but I do not have the precise values of both of these).
Thank you very much!
use tandem and ovoid applicator.
Dear Experts
I am looking for companies working in the field of medical radioisotopes production using electron LINAC. I have searched the web, but I could not find major companies using this accelerator for this purpose.
I want to find out if it is possible to produce radioisotopes, such as F-18, using electron linac (instead of cyclotron).
i want to calculate the number of neutrons producing by an electron linac but i don't find the proper physics reference that can do this:(
How to estimate risk of stochastic effects mainly cancer for a given population exposed to low doses (5-10) mGy per year prevalent in High Background Radiation Areas without using the concept of collective dose as well as ICRP's accepted risk factor of ~5%/Sv?
Hi,
Is anyone able to point me in the direction of where i can buy large volumes of monodisperse silca (SiO2) microspheres, preferably in dry form? I am trying to make a fairly large volume set of phanoms using these spheres and i am struggling to find a supplier that provides more than a few grams which is frustrating?
Ideally somewhere that supplies in at least 50g, although closer to 100-200g would be much more useful.
If anyone knows of any companies then please let me know.
Thank you
Charlotte
From kV and mAs values and without the use of any detectors, how can you find the dose delivered to patients? When using an X-ray, for diagnosis purposes, if you know only the two values of mAs and kV, can you determine the dose or maybe even estimate the dose delivered to the patient? Without the use of any modern detectors.
I have portable 30mA X ray machine with the following specifications:
Output 30mA at 52 KV
20mA at 68 KV
15mA at 85 KV
Timer 0.06mA to 6.0
23 Steps
Tube 1.5 mm sq. Focal Spot X-Ray tube
Input 230V, 15 Amps
L. V. Compensation 210 to 250V
Beam Limination Cone with Centering Device
Weight 15 Kgs.
Dimension (mm) 250x175x250
Can somebody guide me to calculate the dose in gray (Gy)?
Thanking you in anticipation.
In calculation of the absorbed dose in radionuclide scintigraphy, the absorbed dose in tissue T from radionuclide in a single source organ S is given by:
D(T <-- S)= As x S (T <-- S)
where As is the cumulated activity.
I want to calculate the absorbed dose of the kidney in renal scintigraphy using 99mTc-DMSA. I have measured the activity of the rat's kidney using dose calibrator. for calculation of the absorbed dose in a period of time, I need the S-value for rat's kidney and 99mTc-DMSA.
How can I find or calculate it?
Or:
Is there another way to calculate the absorbed dose in rat's kidney from measured activity?
Thanks
Kaveh
Is it possible to rotate the current spin states of electrons of cancer cells with some kind of non-elastic collision via high intensity photon particles to stop cancer progression in last stage.
What is the best method to assess the absorbed dose by the target organs in nuclear medecine examinations?
Quelle est la meilleure mmethod to assess the absorbed dose by target organs in nuclear medecine examinations ?
I'm using a Catphan phantom with an small bead to generate a MTF of a CT scan, so as I understand the matrix of CT numbers of the image of the impulsive signal is my PSF, right?
How do I get rid of the background signal? Do I make an average of the CT numbers in the matrix that apparently do not belong to the impulsive signal and subtract it element by element? when I try to do this I do not obtain the characteristic MTF so there must be another way.
Rencently, I have been doing some experiments on temperature measurement of Argon plasma. I used the boltzmann plot method. I found that the fitting error is about (+-)1000 K. How can I decrease the error from experiment?
Hello, I'm building a ALD reactor in lab scale and I have a few questions referring to the security of operation. As known, most of ALD precursors such as TMA are pyrophoric, but how dangerous can it be, when an exhaust gas composed of small amounts of TMA diluted in nitrogen come in contact with oxigen? what is the best way to deal with exhaust gases of this kind of precursors when discharging at the atmosphere?
To measure grass alpha and beta by Low level Counter (gas proportional counter made by THERMO company) for meat and vegetable samples, the first, we prepare samples in format of ash, now the question is: what temperature must be selected to make ashes of these samples so that for example Cs-137 (as beta emitter) to be reminded in samples.
What temperature and why?
Dear colleagues
This question is a continuation of the considerations set out in the previous question:
My new question is:
How to decrease the resistance of transmission WiFi in a strong EM field from the MV line (60Hz)?
Is the direction of WiFi antenna affects the transmission of data from sensors in the vicinity of the MV line?
What physical phenomena are accompanying the data transmition of WiFi antenna in the strong magnetic field of 60 Hz?
Whether any standards are available in this matter in USA and EU?
I would be gratefull for your sugestions and giving me sample papers on related problems.
Best Regards,
Piotr
We want to generate an external beam of neutrons from a Synchrotron for experiments.
Physics experts in gamma and beta radiation detection.
Medical Physics.
For my project, I need to take FFT of MRI image and for that, I am planning to start with taking the FFT of a dipole corresponding to the sample. My question is, how to identify the dipole in the MRI image ?
I have the data in the form of a 3D array and using MATLAB for programming. My assumption is that first I need to convert this array into k-space matrix. Any suggestions ?
Hi Dear friends
I want to work with CR39 films for neutron dosimetry for the first time. I need help for knowing about 1) the interaction between films and neutron or other particle (which is produced by high energy photons like 15Mev) which make track on films, etching procedure and reading the track.
Do they record the fast or thermal neutron or both of them?
Beyond vendor-specific definitions, what is the theoretical difference between FISP (fast imaging with steady-state precession) and bSSFP (balanced, steady-state free precession)?
What is the number of bunches per MU and what is the delay between them?
Hi,
I am irradiating some mammalian cells comparing both X-rays and protons. I know what dose I am exposing my cells to using X-rays, for example 4Gy, but if I want to radiate with protons how can I work out the equivalent dose in protons?
Thank you for any guidance