Patient Size Dependent Dose for Consistent Low Contrast Detectability in Abdominal CT

Tech Id: zho000725



The technology is a quantitative model for radiation dose adjustment for a wide range of patient sizes for consistent low contrast image quality in X-ray CT imaging. While CT scanning has become a prominent diagnostic tool, the public has increased concerns about the radiation dose, especially the dose to pediatric patients. The result is a move towards reducing radiation dose to the minimum required for a particular patient size, lesion size, and discernable contrast need. Despite widespread agreement among radiologists that radiation dose should be adjusted for specific imaging scenarios, a lack of quantitative relationship means no standard dose adaptation methodology exists.


The researchers define a general model relating these imaging parameters, allowing radiologists to determine and apply the minimum required radiation dose for a particular imaging scenario.



Technology Description

The researchers describe the relationship between minimum detectable contrast, lesion size, patient size, and radiation dose in abdominal CT scans:


MDC=A(L) dB(L)DoseC(L)


MDC is the predetermined detectable contrast, d is the lesion size, Dose is radiation dose, A(L), B(L) and C(L) are pre-determined fitted parameters for the CT imaging system and L is the determined value for the size of the subject.


This relationship follows a power law distribution with fitted parameters specific to each scanner.


The researchers have validated the model using tissue equivalent abdomen phantoms representative of infant to large adult patients.


The model was verified on two modern 64-slice scanners, and the same methodology can be extended to other scanners


For scans reconstructed using iterative reconstruction algorithms, the researchers also relate minimum detectable contrast to blending fraction.



Stage of Development

Working prototype with in-vitro data.



Reduces CT radiation dosage without compromising CT image quality.



This model can be implemented and validated on a commercial CT system to effectively reduce radiation dosage.


Intellectual Property

• US non-provisional patent application 14/910,314 filed.



1. Yifang Zhou et al. On the relationship of minimum detectable contrast to dose and lesion size in abdominal CT. Phys. Med. Biol. 2015 Oct 7;60(19):7671-94. Link


Patent Information:
For Information, Contact:
Julien Brohan
Yifang Zhou
Radiation Control