Latest / Cat Scan Guru Podcast / EP. 80 Part 2: Rotation Time in CT

Transcript

EP. 80 Part 2: Rotation Time in CT · Cat Scan Guru Podcast

• 0:00
  Hello, hello, welcome back, everybody.
• 0:01
  Welcome back to the CAT Scan Guru podcast.
• 0:04
  How are you guys doing? So I know it's been a hot minute
• 0:08
  since I've dropped podcast episodes.
• 0:10
  A lot has been going on that I'm going to share and we're just
• 0:16
  going to get into and then I'm going to dive in to Part 2 of
• 0:21
  the two-part series I started on TikTok when it comes to pitch
• 0:24
  and rotation time. So let's first get all the
• 0:27
  housekeeping stuff done. Well, Christmas is around the
• 0:29
  corner and please don't come after me.
• 0:33
  No, I haven't started my Christmas shopping.
• 0:35
  Yes, I know it's terrible. However, you know, life, just
• 0:39
  life sometimes and that's just what fucking happens.
• 0:42
  So. But I'm going to get to it
• 0:44
  hopefully by this weekend, even though I do have to work all
• 0:46
  weekend, but I'm going to make shit happen because I'm a mom
• 0:49
  and I just make shit happen. So plus, you know, it is colder
• 0:53
  than cold and snow on the ground.
• 0:55
  So yeah, I am not a fan of that considering that I grew up in
• 0:58
  the desert and I'm a West Coast person.
• 1:01
  Give me beach, sand, sun all day long, I'm good.
• 1:04
  So let's kind of get a little bit of housekeeping out of the
• 1:07
  way. So if you guys are interested in
• 1:10
  CT courses because I know I've had a lot of DMS and things like
• 1:14
  that and questions, make sure you guys check out the show
• 1:17
  notes. I will list all the courses that
• 1:19
  I have available and there are new things coming for 2026.
• 1:25
  So make sure you stay tuned to the next episode because I'm
• 1:30
  going to be releasing 2 episodes this week.
• 1:32
  So make sure you guys stay tuned for that and I will have more on
• 1:36
  that. So if you're interested in
• 1:38
  courses, I make it very affordable.
• 1:40
  I make it very easy, very easy to follow and the platform that
• 1:44
  I use, there's an app that comes with too.
• 1:46
  So make sure you guys check out the show notes for all those.
• 1:50
  Make sure you guys subscribe to the show so you can check out
• 1:53
  when the next new podcast episode comes out.
• 1:56
  As always, thank you so much for everybody who has subscribed,
• 2:00
  has shared, has favorited, has continued to listen.
• 2:05
  And even if you're new here, thank you for making this
• 2:10
  podcast show possible because without you, it just would not
• 2:13
  be possible. So also give me a follow on
• 2:15
  TikTok. I post a lot of educational
• 2:18
  stuff on TikTok. And I know I've kind of, you
• 2:21
  know, slowed down on posting. It's just I'm trying to get some
• 2:25
  things in my life with better home work, life balance and
• 2:29
  children. And they're getting ready to get
• 2:31
  on Christmas break here. So that should be fun.
• 2:34
  And I just have to entertain the hell out of them while they're
• 2:38
  home, you know, from school. So make sure you guys check out
• 2:41
  the show notes. All that good stuff will be
• 2:43
  there. So let's get into today's
• 2:45
  episode. So in today's episode, this is
• 2:48
  Part 2. I know you guys have been
• 2:50
  waiting for this, and I'm sorry it took so long.
• 2:52
  We're going to be discussing rotation time when it comes to
• 2:55
  CT. So this is Part 2 of the
• 2:57
  two-part series. OK, so if you are a brand new
• 3:00
  technologist and you are unsure of what rotation time is, I'm
• 3:05
  going to give you the very easiest definition of rotation
• 3:08
  time. So rotation time is the duration
• 3:10
  the X-ray tube and the detectors need to complete one full 360°
• 3:16
  rotation around the patient. OK, so that is what rotation
• 3:19
  time is. So it's how fast or slow your
• 3:22
  detectors and X-ray tube are moving, being inside the gantry.
• 3:26
  So because those things move simultaneously because of
• 3:29
  slippering technology, which is another term be another podcast
• 3:33
  episode for another day. So why is this important?
• 3:36
  Because this is a very important factor when it comes to our
• 3:40
  image quality and the exams that we do.
• 3:42
  So your image quality and your dose is always affected with
• 3:45
  rotation time depending on how fast or slow the X-ray tube and
• 3:50
  the detectors are moving. OK, Now what are the effects of
• 3:53
  rotation time? Because different exams have
• 3:56
  different rotation times, right? So the effects of whether you
• 4:00
  have faster rotation times or slower rotation times, and I'm
• 4:03
  going to go ahead and explain both.
• 4:05
  So faster rotation times, what happens is, is they reduce any
• 4:09
  image artifacts, any blurring in your image and it gives you
• 4:12
  better temporal resolution when it comes to your image.
• 4:15
  But it also comes with higher radiation dose.
• 4:19
  But now with modern scanners in just how technology just keeps
• 4:23
  advancing. Now we don't have to compromise
• 4:26
  so much image quality due to different types of technology
• 4:30
  that keep coming out. Typically when you use a faster
• 4:33
  rotation time, yes, it will increase your radiation dose to
• 4:36
  the patient. Now when you have slower
• 4:38
  rotation times, that does increase your image artifact,
• 4:42
  the blurriness, image noise, all those things OK, but it does
• 4:47
  lower the amount of radiation you are giving your patient.
• 4:50
  OK. Now these two factors along with
• 4:53
  pitch do go hand in hand because when those two factors are
• 4:58
  incorporated, it can affect how better or diminished your image
• 5:04
  quality is or how you know lower or higher your radiation doses.
• 5:10
  OK, so typically in exams, the range of rotation time usually
• 5:17
  averages about to a .5 to one second rotation time depending
• 5:22
  on what type of exam you are executing.
• 5:24
  Now the times that we do have like a rotation time of like
• 5:27
  point 2.3, it's usually when we're doing cardiac scanning
• 5:31
  because we want to minimize the movement of the heart because
• 5:34
  you know, the heart is beating fast, OK?
• 5:36
  Or, you know, when we give the beta blockers, we slow down, you
• 5:39
  know, the heart rate so we can get a nice clean image.
• 5:43
  And that's why we need faster rotation times when it comes to
• 5:46
  cardiac imaging. Now, also with chest imaging,
• 5:48
  like when we're doing PE studies, we need a faster
• 5:51
  rotation time because we want to minimize the movement of
• 5:53
  everything that's going on in the heart and the chest, the
• 5:56
  lungs. But you know, you name it,
• 5:57
  right? So those are very important
• 5:59
  factors. Now another exam that we
• 6:03
  typically use a faster rotation time is, is for neuro exams like
• 6:07
  your CTA work, your CTA head and neck, your perfusion studies
• 6:10
  because we want the nice temporal resolution because you
• 6:14
  want to see all those vessels in the head and neck and you want
• 6:18
  to see the brain perfusing to see if there is tissue that is
• 6:22
  salvageable or if there is dead tissue when it comes to stroke.
• 6:27
  OK, so those are the important factors when it comes to
• 6:30
  rotation time. Now when it comes to the factor
• 6:33
  of pitch, usually because you have an exam that you're doing,
• 6:37
  let's say you know an abdomen and pelvis and you need a faster
• 6:41
  pitch to get through the anatomy, you typically going to
• 6:44
  have like a .5 rotation time when it comes to that.
• 6:47
  So usually they go hand in hand, OK.
• 6:51
  And usually with cardiac imaging, you want a slower
• 6:56
  pitch, but you're going to have a faster rotation time because
• 6:59
  you're trying to get that nice detail when it comes to cardiac
• 7:04
  imaging. Hopefully that all makes sense
• 7:05
  because those things are important things.
• 7:08
  And these are some things that you should take away and make
• 7:11
  sure that you study when it comes to the CT registry because
• 7:14
  some of these questions you get asked on that depending on, you
• 7:17
  know, what type of test you get thrown at.
• 7:19
  So these two factors go hand in hand because you want good image
• 7:23
  quality. We're always trying to make sure
• 7:26
  that the patient gets the correct radiation dose to make
• 7:29
  sure that they get the lowest dose as possible, but we don't
• 7:33
  want to sacrifice image quality at all.
• 7:35
  Now, one tip that I can take away here is as far as adjusting
• 7:40
  your technical factors. I do not recommend texts that
• 7:44
  are new, that have less than three years of experience to be
• 7:48
  altering any technical factors unless you understand why this,
• 7:53
  you know why you're doing it and how it affects your image
• 7:55
  quality and how it affects your radiation dose.
• 7:58
  You have to know why and the effects of it before you can
• 8:01
  start doing that. Now most of bus experienced
• 8:04
  techs like myself, we know exactly why we're adjusting it
• 8:07
  and how to clean up that image because sometimes we have larger
• 8:11
  patients that are over 400 lbs. And what we have to do is we
• 8:15
  have to try to figure out a way how to go ahead and clean up
• 8:20
  that image quality, OK? And we have to figure out
• 8:23
  sometimes we have to hit them at 140 KB because a lot of the
• 8:27
  bariatric protocols do come with 140 KB.
• 8:30
  So we have to make sure that we understand why and the effects
• 8:34
  of not only your image quality, but your radiation dose, which
• 8:38
  is super important. OK, so I made this episode kind
• 8:42
  of short. So just to make sure that you
• 8:44
  guys get all, you know, the pieces of this and knowing how
• 8:48
  rotation time does affect your image.
• 8:50
  And you know, when you're out there, you know, in your on the
• 8:54
  floor. So when you're out there, you
• 8:56
  know, working the job and you know, you can take a look at
• 8:59
  your protocols and see what kind of rotation times you have in
• 9:02
  the different types of pitch because every facility is
• 9:05
  different and the protocols vary from not only state to state,
• 9:09
  but facility to facility in every state.
• 9:12
  OK, so hopefully this was helpful in this two-part series.
• 9:16
  So if you want to know about pitch, make sure you listen to
• 9:19
  the prior podcast episode because that is Part 1 or I
• 9:22
  discuss all the things about pitch, OK?
• 9:24
  Also make sure you guys share, like comment, share it with
• 9:28
  somebody that needs to hear this and hopefully they do learn
• 9:32
  something from this. So thank you so much for joining
• 9:35
  me on this episode and I will chat with you guys in the next
• 9:38
  episode.