User:511KeV/CT Scan Progress

Classifications
As a fellow Wikipedian, I have some humble suggestions. This is a general article regarding CT scan, although it achieved the Good Article status, it should need a major writeup because a general article should cover everything. There are too much headings in the article, some of the headings maybe grouped together and summarised to prevent the article from getting too long. Some not important images should be removed e.g. (figues 2, 6, and 12) as these images illustrate the same thing reptitively. How to measure bronchial wall is too specific for a general article like CT scan. The following are the rough guides for this article:

-Classifications of CT scan machines from 1st generation (translate-rotate tube-detector movements) until the fifth generation (electron beam scanning) ✅

-Classifications according to the xray tube, detector, and patient's table movement: step and shoot CT, spiral CT (due to slip rings, like brushes on an electric motor) ✅

-Classifications according to the X-ray tube source and shape of the xray beam: pencil beam CT (overlapped with first generation CT), fan-beam CT (overlapped with second generation CT), Cone beam CT ✅

-Classifications according to the detector size and shape: single row of detectors, multiple rows of detectors (also known as multislice CT detector or MDCT)(https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1123029/), flat panel CT ✅

-Some mention of the latest innovation in CT: the photon-counting CT ✅

-Have to mention which is the most commonly used type of CT machine nowadays and why some of the types of the CTs above are outdated.

-Another special group of hybrid CT machines such as PET-CT, SPECT/CT machine,(used in nuclear medicine) and angio-CT machine (used in angiography/interventional radiology) ✅

Uses
-Medical uses(in imaging): Head imaging, body imaging (neck, chest, abdomen/pelvis), musculoskeletal (spine and peripheral limbs) (done in general hospitals), CT coronary arteries (done in cardiac centres), CT perfusion imaging in brain and heart (done in dedicated stroke and heart centres respectively)

-Medical uses (in interventional radiology/angiography) such as CT guided lung/abdominal mass biopsy, CT guided drainages, nephrostomies (although although majority of drainages are done through ultrasounds and nephrostomies are done under fluoroscopy)(are usually done in hospitals with interventional/angiography suites) ✅

-Some mention of its industrial uses as mentioned in this wiki article Industrial computed tomography ✅

-Some mention of its use in archeology as mentioned in this wiki article Paleoradiology

-Some other uses which I may have missed out.

Procedure
-Procedure should be placed before the "interpretation of results". And the procedure should consists as follows: whether contrast is needed or not for patient preparation.✅

-non-contrasted CT: head to look for bleed, infarction, skull/facial fractures, or foreign bodies) in HRCT lungs to look for interstitial lung disease, fibrosis, in HRCT temporal to look for cholesteatoma, otitis media, location of cochlear implant (complement with MRI scan of the head)

-Contrasted CT usually in portal venous phase in abdomen and pelvis scans (to look for bowel obstruction, abscesses). Multiphase CT (in liver, kidney, pancreas, adrenals) to look for masses or tumours. Also multiphase CT mesentery to look for bleeds, bowel ischemia, thrombosis. Dedicated CT arterial of the head to look for brain vessels stenosis. CT venography of the head to look for venous thrombosis. CT arterial of the lower limbs in acute limb ischemia and peripheral vascular disease.

-The indications of using oral and rectal contrast in CT or just plain water as negative contrast.

-Whether there is any need of fasting before procedure

-For sedation if patient is restless

-A topogram is taken to plan the coverage and orientation of the scan.

-Spiral scan is done and the scan is complete if it is a non-contrasted scan.

-For contrasted scan, scanning delay for how many seconds depending on the arterial, venous, or delay scans.

-Other techniques: test bolus, bolus tracking, etc for contrasted scan.

Mechanism
-The most commonly used slice thickness (or detector thickness) in CT machines nowadays.

-Description on how the CT machine works: X-ray beam rotates around the patient while shooting the xray beam, the detectors receives the X-rays, either filtered back projection (straightforwards,requires less computer processing power, but less used now due to more noise in data) or iterative recontruction (better images but calculation intensive, increasing used in modern CT machines because of better computer processing power), linear attenuation coefficients are calculated and put into each voxel, followed by CT numbers (in hounsfield units) are calculated and greyscale images are produced.

-Please explain the term "sinogram" and how it fits to the CT image acquisition process as described above.

- Define CT pitch and its effect on image reconstruction.

Interpretation of images
-the reconstruction algorithm can combine e.g. 1mm slices during scanning into thick 5 mm slices. Also multiplanar reconstruction, maximum and minimum intensity projections, volume rendering techniques (each reconstruction algorithim deserves to have their own subheadings) ✅

-Regarding windowing, since the CT machine acquires millions of shades of greys while human eye can only identify 20 to 500 of them (need to check the source), windowing is used to see a specific aspect of the scan images (soft tissue, bone, stroke, subdural effusion windows etc). Radiologist can manually adjust the windowing.

-artifacts are well described. If images for important artifacts such as ring, streak or partial volume artifact is available, it will be much better. ✅

Adverse effects
-The primary concern in CT scan is still contrast allergy. Contrast allergy can be divided into mild and moderate (idiosyncratic reaction), and severe (death), risk of contrast extravasation.✅

--The scan dose depends on the procedure (CT abdomen/pelvis and CT chest produce higher dose than CT head only) and some techniques such as collimation, using multidetector CT, electron beam CT, dose reducing software, adjust the amount of kV used according to patient's BMI are able to reduce doses.

-Define CTDI and DLP in CT radiation doses. ✅

-Since risk of CT radiation causing cancer is controversial, you can put this as last section. ✅

-Some discussion on benefit to risk ratio when a clinician decided to order for a CT scan.

History
The history should not be two or three sentences. A brief description of the evolution of Tomography before the invention CT in 1972 will make the history section interesting. You can put a brief description of the evolution of CT machines from 1st to 5th generation CTs in this section, with the year that it first appears and the companies that first produced it, how profitable for the sale of each CT machine etc. Also, some mention of which company produces the photon counting CT machine. Some mention of the history of applications of CT in industrial and archeology applications.

Hope that this information is helpful for your write-up. If you feel overwhelming, you may consider focusing on one aspect of the CT machine (e.g. types of CT machine, mechanism of CT machine, interpretations of CT images) and submitting it to Wikijournal. Once the Wikijournal accepts it, you use the wikijournal article to update back the Wikipedia article section.