RT Journal Article
SR Electronic
T1 Radiation exposure during PET-CT transmission imaging with 6 and 64-slice-CT scanners
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP 1485
OP 1485
VO 50
IS supplement 2
A1 F Zito
A1 Luca Zappa
A1 Cristina Canzi
A1 Lorenzo Leonardi
A1 Giovanna Re
A1 Giovanni Tosi
A1 Mauro Schiavini
A1 Franco Voltini
A1 Arturo Chiti
A1 Paolo Gerundini
YR 2009
UL http://jnm.snmjournals.org/content/50/supplement_2/1485.abstract
AB 1485 Objectives To study how increased number of CT detector elements can affect dose exposure in routine non diagnostic WB PET-CT studies. Methods Organ doses for eyes, thyroid, lungs, breast, stomach, kidneys, uterus, testes, were assessed with 65 triplets of TLD positioned in the Alderson-Rando humanoid-phantom. It was irradiated twice with an Emotion 6 and a Sensation 64 (6 and 64 slice CT), part of two different BIOGRAPH PET-CT (Siemens) scanners of two nuclear medicine departments in Milan. CARE dose 4D and routine CT departmental protocols (Emotion 6: 50 mAs and 110 kVp for topograms, 95 reference mAs, 130 kVp, 0.6 sec/rotation, collimation 6x3mm, feed/rotation 27 mm for CT scans; Sensation 64: 35 mAs and 120 kVp for topograms, 90 reference mAs, 120 kVp, 0.5 sec/rotation, collimation 24x1.2 mm, pitch 0.8 for CT scans) were used to irradiate the phantom. Effective tube current (mAs) supplied on average and per slice and CTDIvol (mGy) values were also considered. Results For Emotion 6 and Sensation 64, respectively, the following results per scan were obtained: average current 38 mAs and 46 mAs (range 16-55 mAs and 18–68 mAs), 4.11 mGy and 3.16 mGy as CTDIvol . Except for thyroid where dose values were comparable (5 mGy), all other considered organs received on average 20% higher dose with Emotion 6 (range 3.0 – 9.0 mGy) than with Sensation 64 (range 2.0 – 5.5 mGy). Conclusions For this study, 64 vs 6 slice CT scans allowed an average patient dose reduction of 20%.