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JakeS
Radiation dose based on time only would be difficult. As in CT there have been new technologies developed for the fluoroscopic units, which reduces dose. Digital fluoro units have the ability to work w a technique known as pulse progression fluoro. With older fluoro units the operator activated fluoro the tube/x-ray beam was continuously on until they took their foot off the pedal.

With pulse fluoro the tube actually pulses rapidly between on and off. The transition between on and off is so fast that the human eye does not detect it looking at the monitor. It does reduce radiation.

The dose people see is usually extrapolated by the unit from couple of things, such as beam field size and tube output. Many systems use what is called Dose Are Product (DAP) or some call it Karma Are Product (KAP) . If you have seen one of your digital x-rays, like a CXR, if you look at the header info on the radiograph you may find a number followed by mGy or Gy. This is the same concept. The tube measures output of tube and the size of the field selected and extrapolates data to give the dose. Please realize the number is usually a skin or entrance dose because beam energy will vary as it traverses the body.

There are timers that continuously indicate to the operator how much beam on time has occurred.

Fluoro units have a brightness control feature. Based on signal out of the patient the tube will decrease/increase output as the system senses the signal. For example if the EP has just put a catheter in your femoral vessel the patient’s tissue density is different because you over the abdomen/pelvis. As the catheter advances and they follow it the tube output will change as the catheter gets over the chest which is less dense. Another dose reduction technique. Lastly, the size of the patient influences tube output.

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Johnnyk80

I received 5 minutes of Flouroscopy time during my ablation (which is a very low flouro time for an ablation I'm happy to say).

Any insights on how much radiation 5 min of Flouroscopy gives a patient? I presume still less than a CT, but I'm not sure.

John

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JakeS
the high radiation level of CTA

Radiation dose concern is understandable. A couple of points. The dose for CCTA has been reduced almost 80% over the last 10 years or so. The scanners have technologically advanced. Scanners are being replaced. Most Scans are done on 128 slice units. The x-ray tubes continue to be improved, resulting in lower output. Scanning algorithms are better. The spatial resolution (think detail) the CT scan provides is better than an MRA.

Also, the dose from the scan is limited to the field of view (FOV) selected by the technologist based on protocols. It is NOT a whole body dose


What often gets left out of the discussion on dose is risk vs benefit. The risk of cancer, and it is low, is worth the benefit the scan provides. For example: A patient that has CAD has a greater chance/risk of having catastrophic cardiac event than developing a cancer from the scan. The CAD patient that declines the CT out of radiation dose concern may put themselves at a greater risk. The CTA for the ablation helps the procedure more than the dose risk of having the scan.

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JakeS
CTA is a fast exam. I know everyone is different but I only felt one of the sensations the tech will tell you and it was short lived and never reached the level of feeling uncomfortable.

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Yuxi
John,

I am glad it went so well with you. Did you stop all meds before the procedure? Is that why you went into Afib during the procedure? What other meds have you been taking besides Flecainide? Are you expected to continue them after the procedure? for how long?

I am scheduled the same procedure next month with Dr Reddy. I am going for TTE this afternoon and CTA in two weeks. A little scared about the CTA but was told this is the prerequisite for the Kardium trial.

I am also wondering what would they do if I stayed in NSR during the procedure? Do they ablate the PV area anyway?

Appreciate your information!

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Johnnyk80
... and upon completion they remapped my heart and found no afib. I'm not exactly sure what all that means but I suspect that it means the afib was coming from my pulmonary veins....ill be scared to death to stop it, its worked so well for me, but that is why I got the ablation, to be drug free. Se we shall see.

john

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SailorGuy1
Daisy… I had a PFA last year with Dr Natale in Austin; he ablated the pulmonary veins as well as the posterior wall. PVI + posterior wall is his standard procedure. This was the AdMIRE trial.