1Dose rate determined according to IEC 60601-2-54, 203.5.2.4.5.102, System set up: detector format 43 x 43 cm (17 x 17"), patient type children, 0.1 mm Cu + 1 mm Al filter, reduced dose and pulsed slow fluoroscopy mode with 2 pulses/s, Phantom: 5 cm (2 in) PMMA
2Relative difference of two reference air kerma rates between system with GCF and system with PCF
Children are more sensitive to radiation than adults, so it is even more critical that pediatric fluoroscopy follows the ALARA principle (As Low As Reasonably Achievable) to keep the X-ray dose low.
Pulsed fluoroscopy is an established technology, delivering good image quality at a lower dose than continuous fluoroscopy. In pulsed fluoroscopy, the X-rays are created in pulses instead of being continuous, and each pulse results in one image frame of a sequence. Different technologies are available to create these pulses and they differ in terms of cost and performance.
With traditional PCF, the high-voltage generator creates the X-ray pulses. However, long power cables from generator to X-ray tube behave like big capacitors, strongly affecting the form of the electric signal they transport.
Therefore pulses are not precisely rectangular, but rounded, having rising edges (ramping) and falling tails (trailing).
This results in unusable extra dose for the patient (low-energy X-rays, often called soft radiation). This radiation should be avoided because it contributes to patient dose but does not have enough energy to reach the detector, and therefore it does not contribute to the imaging process.
With traditional PCF, the high-voltage generator creates the X-ray pulses. However, long power cables from generator to X-ray tube behave like big capacitors, strongly affecting the form of the electric signal they transport.
Therefore pulses are not precisely rectangular, but rounded, having rising edges (ramping) and falling tails (trailing).
This results in unusable extra dose for the patient (low-energy X-rays, often called soft radiation). This radiation should be avoided because it contributes to patient dose but does not have enough energy to reach the detector, and therefore it does not contribute to the imaging process.
