PHYSICS QUESTION 1 MALVERN VENGESAI   SCANNING A LIVER While scanning a liver, I would choose to do it either between or under the ribs instead of through the ribs because when an ultrasound beam goes through the liver tissue and encounters a rib, it will reflect off Not quite sure what you mean here. This is because of the difference in acoustic impedance of the liver tissue and the bone tissue in the ribs.references needed Consequently, the imaging will be poor because a lot of sounds was reflected leaving much lesser sound to penetrate through and complete the imaging.ref Acoustic impedance (Z) refers to the physical property of a tissue which explains the resistance that an ultrasound beam encounters when it goes through a tissue (Feigelson, Pecau and Perez 2014). Therefore, the ideal way to scan the liver is under the rib and not through the ribs to improve the quality of the imaging. In this case, the quality of imaging will depend on the density of a tissue (p, in kg/m3) and the speed of the sound wave (c, in m/s) and is expressed as Z = p x c. In this case, an increase in the density of a tissue and the speed of sound will lead to a simultaneous increase in impedance (Bolondi and Piscaglia 2015). The amount of reflection that takes place when an ultrasound beam encounters a rib in a perpendicular direction is shown as Reflection fraction = [(Z2 - Z1) / (Z2 + Z1)] 2 whereby Z1 and Z2is the impedance in the liver tissue and the rib tissue respectively. The impedance of the liver tissue is 1.65 × 106 while that of the bone tissue is 7.8 × 106.The reflection coefficients are expressed as: reference. Show me the maths and the workings out and then discuss your answer. The alterantive path is through the muscle vs soft tissue if you were going through the ribs. The intensity of the ultrasound waves directed towards the liver can be compared with the ultrasound waves reflected to the surface by the ribs. These reflected waves are usually lower in terms of intensity due to the reflection and thus, a dB loss occurs (Harvey and Albrecht, 2012). The decibel value for the two different ultrasound waves may be calculated using the decibel scale used in acoustics where the decibel loss will be defined by: reference l0 is the reference intensity for the ultrasound. If the ultrasound wave intensity is halved, 3 dB values are subtracted and if the intensity is reduced by a factor of 10, 10 dB values are subtracted. A negative value usually denotes the dB loss because less than 1% of sound would be reflected where there is such an interface (Gollin, Sims & Cameron 2014). Also consider dB loss as a result of actually travelling a distance through the tissue. Give me this equation and then do the maths and discuss your answer. In conclusion, the main reason I will choose to scan the liver under the ribs and no through the ribs is because of the differences in the acoustic impedance of the liver and the bone tissues in the ribs which will substantially affect the quality of the image. Therefore, by scanning under the rib, the ultrasound beam will not undergo any resistance as it goes through the rib tissues. You are on the right track here, but you haven’t quite touched on all the relevant concepts. Running your assignments through the your tutor service would assist you with grammar and ensuring that it makes sense to the reader. I can see what you are trying to say here, but I don’t get a real sense of understanding. Watch the discussion board for assignment hints and tips. You needed to present the relevant equations and do the maths and discuss your answer. Watch the referencing too, you need to make sure all your information is referenced. A good start though. Reference list Bolondi, L., Correas, J.M., Lencioni, R., Weskott, H.P. and Piscaglia, F., 2007. New perspectives for the use of contrast-enhanced liver ultrasound in clinical practice. Digestive and liver disease, 39(2), pp.187-195. Feigelson, J., Pau, Y. and Perez, R., 2013. Liver scanning and liver function in cystic fibrosis. Acta Paediatrica, 61(3), pp.337-342. Gollin, F.F., Sims, J.L. and Cameron, J.R., 1964. Liver scanning and liver function tests: A comparative study. Jama, 187(2), pp.111-116. Harvey, C.J. and Albrecht, T., 2012. Ultrasound of focal liver lesions. European radiology, 11(9), pp.1578-1593. Have a look at how to format the reference list. l .