Our vision is to empower Biomedical engineers and Doctors to acquire, demonstrate, articulate and va
03/09/2022
القطط تقدر تشرب ميه مالحه بدون ما يحصلها جفاف لان الكلى بتاعتها فيها فلاتر بتنقي الملح
لكن اغلب الحيونات بما فيهم الانسان ممكن يموت من الجفاف او شرب المياه المالحة
Cats can drink seawater without becoming dehydrated because their kidneys are efficient enough to filter out the salt.
Most animals, including humans, would likely die of dehydration.
03/09/2022
الطفلة "مروة" بائعة المناديل في أسوان ذات الـ 10 سنوات ..
ذهبت لتشاهد من بعيد ماراثون للأطفال نظمته مؤسسة مجدي يعقوب الخيرية للقلب، فأسرعت نحوهم لتطلب المشاركة بكل براءة .. رغم أنها لا تملك رسوم الاشتراك 200 جنيه ولا حذاء وزياً رياضياً للمشاركة .. ولكن كانت تمتلك رغبة بالفوز!
المنظمين لم يحرموا حقها كطفلة في اللعب، كنوع من الدعم النفسي، ركضت مروة حافية القدمين.. ركضت كما اعتادت أن تركض خلف الزبائن في الطرقات لبيعهم المناديل... ركضت بعزة الفقير ركضت وكأنها تطير نحو السماء لتعانق خط النهاية.😭
ليتفاجئ الجميع بحصولها على المركز الأول والفوز بالميدالية الذهبية وسط ذهول الجميع وتصفيقهم وبرقم قياسي ❤
One fateful day around 1895 avid gardener and economist Vilfredo Pareto noticed something peculiar. Only 20% of the pea pods in his garden produced an astounding 80% of the crop.
Pareto then applied this principle to the macroeconomics in his homeland of Italy. What did he find? A whopping 80% of the land was owned 20% of the people.
Since then, the Pareto Principle, which is also known as the 80/20 Rule, has been applied to nearly every facet of life.
In business, 80% of a company’s sales come from 20% of its customers. For athletes training, 20% of the exercises and habits have 80% of the impact. And, when it comes to traffic accidents, 20% of motorists cause 80% of them.
You can unlock enormous potential by leveraging the magic of 20%.
27/02/2021
Radiation Applications in Medical Field
this is the link to the recorded online webinar for who missed the event
Wish all of you the best
Radiation Application in medical field The lecture is an overview about the radiation physics and medical imaging modalities
22/02/2021
What are the radiation applications in the medical field? Join us on our live lecture to obtain high-quality, healthcare education reviewed by leading experts in the field.
Registration Link: https://lnkd.in/eSfP3qy
MRI physics 9
T2 relaxation
After removal of the radio frequency signal, the protons will relax back into their baseline position.
The first thing that happens is that the protons and their associated spins repel each other and push the protons apart(dephasing). all spinning dipoles lose coherence and no longer spin in phase.
As this happens,the transverse magnetization component diminishes. This process is called the T2 or spin-spin relaxation, because it has to do with the interaction of the protons or spins themselves.
T2 is the time taken for the transverse magnetization to decay to 37% of its original value.
Different tissues have different values of T2 and dephase at different rates.
White matter has a short T2 and dephases rapidly. CSF has a long T2 and dephases slowly. Gray matter has an intermediate T2 and dephases intermediately.
There is no net energy transfer
during this relaxation.
23/01/2021
MRI physics 8
TR (Repetition time)
TR is the time between the application of an RF excitation pulse and the start of the next RF pulse.
TR relates to T1 and affects contrast on T1-weighted images.
So now lets discuss 🤔 two cases:
Short TR and long TR
long repetition time:
allows the protons in all of the tissues to relax back into alignment with the main magnetic field so when we apply second 90 degree RF pulse, protons in all of the tissues will have the same transversal magnetization which mean there will not be any contrast between tissues in T1 Weighted Image.
Short repetition time:
will result in the protons from some tissues not having fully relaxed back into alignment with B0 so when we apply second 90 degree RF pulse protons of each tissue will have its different transversal magnetization as not all protons deflected in xy with the same amplitude some fast anothers slow which means high contrast T1 Weighted Image.
Each TR records or fill part of the image
So its repeated process.
As a conclusion we need short TRs to get best high contrast T1 weighted image.
23/01/2021
Physics 7
T1 weighted image (T1WI)
T1WI is a basic RF pulse sequence in magnetic resonance (MR) imaging and depicts differences in signal based upon intrinsic T1 relaxation time of various tissues.
When the RF energy source is turned off, the net magnetization vector realigns with the axis of B0 through the process of T1 recovery, during which the longitudinal magnetization increases in magnitude, or recovers .
Different tissues have different characteristic T1values, which is in large part what allows the differentiation of tissues and disease processes in clinical imaging.
Fat has a short relaxation time (ie. fast recovery)as compared to water because it can more easily transfer its received energy to its surroundings. and what 😳 this mean?
Fat will recover quicker to realign with longitudinal magnetization (Z axis). When a second radiofrequent pulse of 90 degrees is given, both of water and fat will deflect to x-y axis (transevers magnetization)but water will not have fully recovered in the longitudinal plane. After the second pulse, fat will make a larger deflection than water and create more transversal,processed only in the transversal plane.The higher the transversal magnetization of the tissue, the more signal is received and the more intensity signal (white).
MRI physics 6
T1 Relaxation time (spin-lattice Relaxation)(Thermal Relaxation)
After turning off RF pulse what 😳 happens??
Two things happens,In this post will talk about one of them.
High energy protons fall back into their low energy state. As this happens, the energy that was previously absorbed by the proton is dissipated into the surrounding tissues as heat. This is referred to as the T1 or spin-lattice relaxation and it involves the transfer of energy from the spins to the surrounding tissues or lattice.
protons fall back to baseline and the resulting longitudinal magnetization vector increases.
T1 is the time that it takes for the longitudinal magnetization to reach 63% of its final value.
The rate at which this longitudinal magnetization increases is different for protons associated with different tissues.
MRI physics 5
RF Pulses and transversemagnetization:
As we said, What is required is a magnetization that lies at an angle
to B0 to be measurable.
The way to do that is to apply RF pulse to disturb the protons so that they fall out of alignment with B0.
This disturbance occurs through the transfer of energy from the RF pulse to the protons. This can only occur when the RF pulse has the same frequency as the precessional frequency of the protons, a phenomenon called resonance.Accordingly, RF pulses are set at the Larmor frequency.
After applying RF pulse two things happens:
1- protons will absorb some of that energy and flip some of those spins to the higher energy state. If we put enough energy to put 50% of the proton population into the high state, our longitudinal magnetization reduces to zero.
2- protons will synchronize and spin together (in phase).
Now we have a net magnetic force oriented horizontally or at 90 degrees to the longitudinal magnetization. This is called the
transverse magnetization.
The resulting transverse magnetization rotates around as the protons precess and generates a small but measurable current in a regional coil of wire.This current will be used to generate images.
MRI physics 4
protons energy state
As we said before, when appling external magnetic field B0 there will be hydrogen protons aligned up and others aligned down.
What determines the proton’s orientation is the amount of energy associated with each of the individual atoms or protons. The ones with higher energies line up against (anti-parallel)the main magnetic field and are thus considered to be in a high energy state(excited state) because they exerted more effort to be against the main magnetic field. The ones lining up with(parallel)the main magnetic field are in a low energy state(relaxation state).
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MRI physics 3
Longitudinal magnetisation
there are more proton nuclei aligned with the main magnetic field B0 than anti-aligned (antiparallel) to it, This results in a sum magnet field or Net magnetization, in the direction of main magnetic field z axis , this is the longitudinal magnetization
This magnetization is usually the same direction as the large,main external magnetic field, therefore it cannot be measured or detected directly.
When a patient is exposed to the magnetic field of an MRI, he/she essentially becomes a magnet. The magnetic force of the patient cannot be measured as it is in the same direction as the external field. What is required is a magnetization that lies at an angle.