Calculate the contrast of the sphere

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Calculate activity qustions. See the attatchment

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J. A 1.0 cm diameter sphere (to simulate a tumor) is placed inside a20 cm diameter, cylindrical phantom (total volume of 6 L). The sphere is filled with water containing 1.0 MBq of Tc-99m. The phantom is also filled with a Tc-99m water solution, but with an activity of 850 Mbq. a) Calculate the contrast of the sphere. This would represent the contrast seen in a SPECT image. (2 marks) Now consider the imaging set-up shown in the figure. The detector acquires a lD image along x that is I cm thick in the z-direction. The sphere is located at a distance of (x, y) : (5 cm, 5 cm) from the centre of the phantom. The sphere is centered in the camera, with regard to the zdirection. The centre of the phantom is a distance of 30 cm from the imaging plane. The resolution of the scanner (including effects from all sotuces, i.e. collimator, crystal, etc.) is 12 mm @WHW). Assume an ideal, parallel-hole collimator. b) Neglecting l/f and attenuation artifacts, plot the relative counts, as a function of x, as seen on the detector. Assume perfect resolution. Calculate the contrast of the sphere in the image. Why does this contrast differ from that found in a)? (4 marks) c) Repeat b), but now include llf and attenuation affects. How do the recorded counts and calculated contast differ from that found in b)? Explain the differences. (4 marks) d) Redo c), but this time, include the effects of resolution. Label and explain the differences between the two sketches. (2 marks) e) Is there any location within the phantom that the sphere could be placed which would improve contrast? Explain. (2 marks) f) If noise is added to the image, would you expect the contrast from d) to change? Explain. (2 marks) detector a *ly –

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What activity of l-123, relative to Tc-99m, would be required to provide the the same dose to the patient from both tracers?

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A growing alternative to Tc-99m based tracers is I-123, which has a gamma ray energy of 149 keY almost identical to the Tc-99m gamma ray energy of 140 keV, but I-123 has a longer halflife. Assume we have two tacers that are labelled with Tc-99m and I-123 respectively, and that both have identical biodistributions within the body. a. What activity of l-123, relative to Tc-99m, would be required to provide the the same dose to the patient from both tracers? Neglect biological half-life effects. (3 marks) b.

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l. A growing alternative to Tc-99m based tracers is I-123, which has a gamma ray energy of 149 keY almost identical to the Tc-99m gamma ray energy of 140 keV, but I-123 has a longer halflife. Assume we have two tacers that are labelled with Tc-99m and I-123 respectively, and that both have identical biodistributions within the body. a. What activity of l-123, relative to Tc-99m, would be required to provide the the same dose to the patient from both tracers? Neglect biological half-life effects. (3 marks) b. What effect would the use of the above activities have on the SNR of the images? (2 marks) 2. A vial containing Tc-99m is labelled “2 mCi/ml @8 a.m.”. a. What is the activity of the sample at 4 p.m. On the same day? (2 marks) b. What volume should be withdrawn at 4 p.m. On the same day to prepare an injuection of 1.5 mCi for apatient? (2 marks)

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What process does your organisation use to measure and monitor the effectiveness of its services?

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This requires a 2000 word creative essay on one topic out of three topics provided. Details are under the Assignment section. Note that for the creative essay we are expecting you to provide evidence in terms of references for the various points expressed not just on personal experience working in the laboratory. We would expect description of management theories as appropriate). This creative essay needs to be submitted via Turnitin and a hard copy submitted via Medical Sciences reception. Topic The topic will be one of the following options for the purpose of the exercise. 1. What process does your organisation use to measure and monitor the effectiveness of its services? 2. What do you believe are the most common issues facing leaders and managers in your workplace? 3. Provide an example of how you managed a complex staffing/team situation. Provide examples of strategies you needed to consider. Essay length Approx. 2000 words Format Your essay will be a descriptive essay supported by evidence from the literature including both peer reviewed and non-peer reviewed sources e.g. journals, books and personal experience. It will be up to you to validate your sources to ensure the credibility of your essay. You should use illustrations and pictures where possible to support the newsworthiness of your essay topic. If you have downloaded images from the web or scanned images always include the source and permission to use if required. The essay should be word-processed in double spacing using Times New Roman and no less than 12 point font size.

Calculate the effects of the following pulse sequences on thermal equilibrium magnetization.

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 (a) In a sample of 1000 atoms,if 50 atoms decay in 5seconds, what is the radioactivity measured in mCi, of the sample?

b) in order to produce a level of radioactivity of 1mCi, how many nuclei of 99mTc (

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= 3.22X10^(-5)s^(-) ) must be present? What mass of the radionuclide does this correspond to?(Avogadro’s number is 6.02X10^(23).

c) A radioactive sample of 99mTc contains 10mCi activity at 9 am.What is the radioactivity of the sample at 3pm on the same day.

2) In a nuclear medicine scan using 99mTc, the image SNR for a 30-min scan was 50:1 for an injected radioactive dose of 1 mCi (3.7X10^(7) disintegrations per second). Imaging began immediately after injection.

a) if the injected dose were doubled to 2mCi, what would be the image SNR for a 30-min scan?

b) if the scan time were doubled to 60min with an initial dose of 1mCi, what would be the image SNR?

3) Assuming that there are 6.7X10^(22) protons in 1cm^(3) of water, what is the magnetization contained within this volume at a magnetic field strength of 1.5T?

4) Calculate the effects of the following pulse sequences on thermal equilibrium magnetization. The final answer should include x,y, and z components of magnetization.

a) 90x (a pulse with tip angle 90 degrees , applied about the x axis).

b)80x.

c) 90x 90y (the second 90 degrees pulse is applied immediately after the first).

d)80x80y