Conversion of Exposure rate constant to Air kerma rate constant
Briefly on Specific gamma ray constant and Exposure rate constant The specific gamma ray constant is the quotient of Where, is the distance from point source is the exposure rateA is the activity of the nuclide unit : R cm2 h-1 Ci-1 The exposure rate constant has been introduced later on to replace the specific…
Dose Volume Histogram 📈
Introduction Dose volume histogram was first introduced in 1979 by Goitien and Verhey. Dose Volume Histogram (DVH) are presented as structure based DVH and non- structure based DVH. Non structure based DVH are less occasionally used and predominantly structure based DVH is used, though it has gross uncertainties in the precise location of structure. DVH…
Linear Energy Transfer
The density of ionization in particle track is described by the term Linear Energy Transfer (LET). In other words, it is the measure of number of ions produced per unit path length of the track. What is difference between path length and range?The thickness of medium required for entire energy of the particle to be…
Transport Index ☢️🚚
Transport index is the maximum radiation level in mSv/hr, at a distance of 1 meter from the external surface of the package, multiplied by 100 TI = Radiation level at 1m (mSv/hr) x 100 TI 
Radioactive decay law
Radioactive decay is a stochastic process i.e. probabilistic in nature. In simple words, if we have just one unstable atom we will not know when that atom will disintegrate. But when we have a very large number of unstable atoms of same species, The decay can be estimated using probability distribution i.e. we can say…
The time scale of effects in radiobiology 🧫
The process are divided into three phases Physical Phase Chemical Phase Biological Phase Physical Phase In physical phase the interaction between the charged particle with the atoms of the tissues occurs. It mainly interacts with orbital electrons, ejecting some of them from atoms while exciting some electrons to higher energy levels. The secondary electrons with…
why do we use materials with low atomic number for shielding against neutrons 🤔
Types of Neutron Interaction The neutron interaction is one among the major types Scattering and absorption.In case of scattering, when the neutron interact with the nucleus the speed and direction of the neutron changes but the nucleus will be left with same number of neutron and proton as before. The energy imparted to the nucleus…
Stochastic and Non stochastic Quantities 1.1.1
Let us consider a system, The system in itself is not a stochastic or non stochastic one. We define a system to be Stochastic or to be deterministic, thus it can be used to measure the physical quantities in it. In Deterministic model we assume we know everything that’s happening in the system and it…
How is it possible for photons to transfer energy when it has no mass !
E = mc2 is the special case of E2 = ρ2c2 + m2c4 , Its a combination of mass energy and momentum energy. The mass of photon is 0, so they get all their energy from momentum, Energy of photon reduces to E = ρc . e.g. A rope connected to an object in one…
Why Co-60 machine has 80cm SAD?
The reasons are Geometric penumbra and Source Strength Geometric penumbra The width of the geometric penumbra (Pd) at any depth (d) from the surface of the patient is given by From the above image its clear that as source size increases the Geometric Penumbra increasesIn case of cobalt 60 the source size are between 1.5 cm diameter to…
Loading…
Something went wrong. Please refresh the page and/or try again.
Follow My Blog
Get new content delivered directly to your inbox.
Medical Physics Blog 