Re: reported side effects from CT scan of head -- CORRECTION

[John Jacobus <crispy_bird@YAHOO.COM>]

The data I just sent was for the scout views.  The

detailed scans doses are given below.  I apologize for

the error.



Head CT

Female Gonad	3.569 micro Gy

Male Gonad	2.645 micro Gy

Lens	2.829 mGy

Thyroid	1.711 mGy

L Breast	129.0 micro Gy

R Breast	140.0 micro Gy

	

Inner Ear/Temporal Bone CT

Female Gonad	1.877 micro Gy

Male Gonad	1.874 micro Gy

Lens	5.338 mGy

Thyroid	1.451 mGy

L Breast	71.51 micro Gy

R Breast	70.95 micro Gy

	

Sinuses/Orbits CT

Female Gonad	2.046 micro Gy

Male Gonad	2.373 micro Gy

Lens	7.643 mGy

Thyroid	1.845 mGy

L Breast	99.51 micro Gy

R Breast	113.1 micro Gy





Technically, the scout doses should be added to the

scan doses to give a total dose to the organ or

tissue.





--- John Jacobus <crispy_bird@YAHOO.COM> wrote:

> Sorry for the late response to this, but I was away

> from my office last week and could access the data

> we

> have been working with.

> 

> We have made some dose measurements outside of the

> primary irradiation field for various CT scans using

> an RANDO phantom http://www.phantomlab.com/rando.htm

> and a electronic dosimeter with a remote detector

> http://www.unfors.com/rp_edd.php.

> 

> The study being considered below was for an

> evaluation

> of the patient's sinuses.  I have included results

> for

> the a Head and Inner ear/temporal bone as well as

> for

> a Sinus/Orbits exam.  We are using a multislice CT

> scanner, so the results will be lower for a single

> slice unit

> 

> 

> Head CT Exam

> Female Gonad	0.007 micro Gy

> Male Gonad	0.000 micro Gy

> Lens	77.82 micro Gy

> Thyroid	176.7 micro Gy

> L Breast	1.253 micro Gy

> R Breast	1.699 micro Gy

> 	

> Inner Ear/Temporal Bone CT Exam

> Female Gonad	0.041 micro Gy

> Male Gonad	0.040 micro Gy

> Lens	87.80 micro Gy

> Thyroid	238.2 micro Gy

> L Breast	2.070 micro Gy

> R Breast	2.784 micro Gy

> 	

> 	Sinuses/Orbits

> Female Gonad	0.007 micro Gy

> Male Gonad	0.000 micro Gy

> Lens	100.5 micro Gy

> Thyroid	180.3 micro Gy

> L Breast	1.844 micro Gy

> R Breast	2.562 micro Gy

> 

> 

> 

> 

> 

> 

> --- JGinniver@AOL.COM wrote:

> > A relative recently went to an Ear Nose and Throat

> > Specialist due to sinus 

> > problems.   Unfortunately the specialist was

> unable

> > to identify the cause.   The 

> > next step, which the specialist was reluctant to

> > take was a CT Scan, 

> > presumably of the head.   The specialist stated

> that

> > unless the symptoms became more 

> > severe that s/he wouldn't authorise the CT scan

> due

> > to the high levels of 

> > radiation involved.   The specialist then went on

> to

> > state that some individuals 

> > who had recived CT scan (again presumably of the

> > head) had experienced thyroid 

> > problems.

> > 

> > I don't wish to debate the merits or not of

> > prescribing the CT examination.   

> > The Doctors decision not to do this is consistent

> > with guidance in the UK 

> > that they shouldn;t not prescribe a radiation

> > examination unless they believe it 

> > is justified and that the benefits outweigh the

> > risk, albeit small, of the 

> > radiation exposure.

> > 

> > What I would like assistance with is the validity

> of

> > the statement that a 

> > proportion of patients who have recieved CT scans

> > have then experienced thyroid 

> > problems.   Based on current evidence I don't

> > believe that this is possible, 

> > but Medical Physics is   not my field and I would

> be

> > grateful if others with 

> > knowledge and experience in this area could help. 

> 

> > Has there every been any 

> > published study that has managed to identify a

> > statistical link between CT scans 

> > and Thyroid problems.   I intend to write to the

> > Doctor to establish the reason 

> > for this statement, but would like some more

> > information, if it's available, 

> > before I do so.

> > 

> > Thanks for any help you can all provide.

> > Regards,

> >      Julian

> > 





=====

+++++++++++++++++++

"Style is knowing who you are, what you want to say, and not giving a damn"

Gore Vidal



-- John

John Jacobus, MS

Certified Health Physicist

e-mail:  crispy_bird@yahoo.com



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