<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<style type="text/css" style="display:none;"> P {margin-top:0;margin-bottom:0;} </style>
</head>
<body dir="ltr">
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);" class="elementToProof">
Dear fellow GATE-users,</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);" class="elementToProof">
<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);" class="elementToProof">
I am facing issues with a simulation. My geometry consists of a planar X-ray source (120 kVp) irradiating a simple phantom consisting of a large disc (muscle) and three smaller inserts (air, bone and adipose tissue). The detector is positioned behind the phantom
(screenshot of geometry attached). The problem is that when I reconstruct the image based on the counts registered in the detector, I only see the source and no sign of the phantom (attached image.png). This is really odd, as I have previously run the same
mac script but with different materials (uranium, gold, platinum, tungsten) and the image looked as expected (attached image2.png).
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);" class="elementToProof">
<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);" class="elementToProof">
I tried many things, such as only using uranium as a higher absorbing material for the large disc and keeping the smaller inserts as air, adipose and bone, which then makes the large disc appear, but the smaller discs are translucent (image3.png). Finally,
if I only use a bone disc without any inserts, I still see no disc, even though I should be able to see a difference in attenuation between bone and the surrounding air.</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);" class="elementToProof">
<span style="background-color:rgb(255, 255, 255);display:inline !important">Please note that the images have different activity levels, but I don't expect that this to make such a big difference (</span><span style="margin:0px;background-color:rgb(255, 255, 255);display:inline !important">~70e6
Bq for image.png and image2.png, ~7e6 Bq for image3.png, simulation time: 1 sec)</span><span style="background-color:rgb(255, 255, 255);display:inline !important">. </span><br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);" class="elementToProof">
<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);" class="elementToProof">
Has anyone ever experienced similar issues or knows how to solve this? Many thanks in advance!</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);" class="elementToProof">
<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);" class="elementToProof">
Best,</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);" class="elementToProof">
Maggie</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);" class="elementToProof">
<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);" class="elementToProof">
P.S.:</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);" class="elementToProof">
This is my mac script:</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);" class="elementToProof">
<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);" class="elementToProof">
#==============================================================================================
<div># Visualization</div>
<div>#==============================================================================================</div>
<div><br>
</div>
<div>#/control/execute mac/visu.mac</div>
<div><br>
</div>
<div>#==============================================================================================</div>
<div># Materials</div>
<div>#==============================================================================================</div>
<div><br>
</div>
<div>/gate/geometry/setMaterialDatabase data/GateMaterials.db</div>
<div><br>
</div>
<div>#==============================================================================================</div>
<div># Geometry </div>
<div>#==============================================================================================</div>
<div><br>
</div>
<div>/gate/world/setMaterial Air</div>
<div>/gate/world/geometry/setXLength 5 m</div>
<div>/gate/world/geometry/setYLength 5 m</div>
<div>/gate/world/geometry/setZLength 5 m</div>
<div><br>
</div>
<div>/gate/world/daughters/name scanner</div>
<div>/gate/world/daughters/insert box</div>
<div>/gate/scanner/geometry/setXLength 53. mm</div>
<div>/gate/scanner/geometry/setYLength 40. mm</div>
<div>/gate/scanner/geometry/setZLength 2. mm</div>
<div><br>
</div>
<div>/gate/scanner/daughters/name detector</div>
<div>/gate/scanner/daughters/insert box</div>
<div>/gate/detector/geometry/setXLength 0.220 mm</div>
<div>/gate/detector/geometry/setYLength 0.220 mm</div>
<div>/gate/detector/geometry/setZLength 1. mm</div>
<div>/gate/detector/setMaterial CdTe</div>
<div>/gate/detector/repeaters/insert cubicArray</div>
<div>/gate/detector/cubicArray/setRepeatNumberX 240</div>
<div>/gate/detector/cubicArray/setRepeatNumberY 180</div>
<div>/gate/detector/cubicArray/setRepeatVector 0.220 0.220 0. mm </div>
<div>/gate/detector/vis/setVisible 1 </div>
<div>/gate/detector/vis/setColor yellow</div>
<div>/gate/detector/vis/forceSolid</div>
<div><br>
</div>
<div>/gate/world/daughters/name musclePhantom</div>
<div>/gate/world/daughters/insert cylinder </div>
<div>/gate/musclePhantom/geometry/setRmin 0. mm</div>
<div>/gate/musclePhantom/geometry/setRmax 15.84 mm</div>
<div>/gate/musclePhantom/geometry/setHeight 0.1 mm</div>
<div>/gate/musclePhantom/placement/setTranslation 0. 0. 5. cm</div>
<div>/gate/musclePhantom/setMaterial Muscle</div>
<div>/gate/musclePhantom/vis/setVisible 1</div>
<div>/gate/musclePhantom/vis/setColor red</div>
<div>/gate/musclePhantom/vis/forceWireframe</div>
<div><br>
</div>
<div>/gate/musclePhantom/daughters/name airDisc</div>
<div>/gate/musclePhantom/daughters/insert cylinder</div>
<div>/gate/airDisc/geometry/setRmin 0. mm</div>
<div>/gate/airDisc/geometry/setRmax 4. mm</div>
<div>/gate/airDisc/geometry/setHeight 0.1 mm</div>
<div>/gate/airDisc/placement/setTranslation 0. 10.42 0. mm</div>
<div>/gate/airDisc/setMaterial Air</div>
<div>/gate/airDisc/vis/setVisible 1</div>
<div>/gate/airDisc/vis/setColor cyan</div>
<div>/gate/airDisc/vis/forceSolid</div>
<div><br>
</div>
<div>/gate/musclePhantom/daughters/name boneDisc</div>
<div>/gate/musclePhantom/daughters/insert cylinder</div>
<div>/gate/boneDisc/geometry/setRmin 0. mm</div>
<div>/gate/boneDisc/geometry/setRmax 4. mm</div>
<div>/gate/boneDisc/geometry/setHeight 0.1 mm</div>
<div>/gate/boneDisc/placement/setTranslation 0. 0. 0. mm</div>
<div>/gate/boneDisc/setMaterial Bone</div>
<div>/gate/boneDisc/vis/setVisible 1</div>
<div>/gate/boneDisc/vis/setColor white</div>
<div>/gate/boneDisc/vis/forceSolid</div>
<div><br>
</div>
<div>/gate/musclePhantom/daughters/name fatDisc</div>
<div>/gate/musclePhantom/daughters/insert cylinder</div>
<div>/gate/fatDisc/geometry/setRmin 0. mm</div>
<div>/gate/fatDisc/geometry/setRmax 4. mm</div>
<div>/gate/fatDisc/geometry/setHeight 0.1 mm</div>
<div>/gate/fatDisc/placement/setTranslation 0. -10.42 0. mm</div>
<div>/gate/fatDisc/setMaterial Adipose</div>
<div>/gate/fatDisc/vis/setVisible 1</div>
<div>/gate/fatDisc/vis/setColor yellow</div>
<div>/gate/fatDisc/vis/forceSolid</div>
<div><br>
</div>
<div>#============================================================================================</div>
<div># Physics</div>
<div>#============================================================================================</div>
<div><br>
</div>
<div>/gate/physics/addPhysicsList emstandard_opt4</div>
<div><br>
</div>
<div>#==============================================================================================</div>
<div># Outputs & Actors</div>
<div>#==============================================================================================</div>
<div><br>
</div>
<div>/gate/systems/scanner/level1/attach detector</div>
<div>/gate/detector/attachCrystalSD</div>
<div><br>
</div>
<div>/gate/output/tree/enable</div>
<div>/gate/output/tree/addFileName output/tree.root</div>
<div>/gate/output/tree/hits/enable</div>
<div><br>
</div>
<div>#==============================================================================================</div>
<div># Initialisation</div>
<div>#==============================================================================================</div>
<div><br>
</div>
<div>/gate/run/initialize</div>
<div><br>
</div>
<div>#==============================================================================================</div>
<div># Source</div>
<div>#==============================================================================================</div>
<div><br>
</div>
<div># X-ray spectrum</div>
<div>/gate/source/addSource interpolationSpectrum gps</div>
<div>/gate/source/interpolationSpectrum/gps/particle gamma</div>
<div>/gate/source/interpolationSpectrum/gps/energytype UserSpectrum</div>
<div>/gate/source/interpolationSpectrum/gps/setSpectrumFile ../Xray_spectrum120kVp_new_MeV.txt</div>
<div>/gate/source/interpolationSpectrum/gps/position 0. 0. 10. cm</div>
<div>/gate/source/interpolationSpectrum/gps/type Plane</div>
<div>/gate/source/interpolationSpectrum/gps/shape Circle</div>
<div>/gate/source/interpolationSpectrum/gps/radius 21.78 mm</div>
<div>/gate/source/interpolationSpectrum/setActivity 7.36e6 becquerel </div>
<div><br>
</div>
<div>#==============================================================================================</div>
<div># Main program</div>
<div>#==============================================================================================</div>
<div>/gate/random/setEngineSeed 523678<br>
</div>
<div><br>
</div>
<div>/gate/application/setTimeSlice 0.1 s</div>
<div>/gate/application/setTimeStart 0. s</div>
<div>/gate/application/setTimeStop 1. s</div>
/gate/application/start<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);" class="elementToProof">
<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);" class="elementToProof">
<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);" class="elementToProof">
<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);" class="elementToProof">
<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);" class="elementToProof">
<br>
</div>
<p>The Institute of Cancer Research: Royal Cancer Hospital, a charitable Company Limited by Guarantee, Registered in England under Company No. 534147 with its Registered Office at 123 Old Brompton Road, London SW7 3RP.
</p>
<p>This e-mail message is confidential and for use by the addressee only. If the message is received by anyone other than the addressee, please return the message to the sender by replying to it and then delete the message from your computer and network.
</p>
</body>
</html>