IEC 62985 pdf free download
IEC 62985 pdf free download.Methods for calculating size specific dose estimates (SSDE) for computed tomography.
These PHANTOM specifications shall apply unless otherwise stated in the ACCOMPANYING DOCUMENTS, in order to accommodate minor variations from these specifications.
4.3 Characteristics of the anthropomorphic PHANTOM
The anthropomorphic PHANTOM shall be a representative of an average adult human from the top of the head to the bottom of the pelvis. It shall have a comprehensive set of simulated internal organs and bones designed to yield the CT NUMBERS of their anatomical counterparts. The PHANTOM shall include a minimum of simulated soft tissue, lung, and bone.
More than one anthropomorphic PHANTOM may be utilized if, as a set, they are representative of average adult head, chest, abdomen and pelvis regions. In addition, verification with a paediatric PHANTOM(S) may also be performed.
A description of the anthropomorphic PHANTOMS(S) used shall be provided in the
ACCOMPANYING DOCUMENTS.
NOTE If an end user is evaluating the accuracy of D IMP(z) values, differences between DWIMP(z) and DWREF(z) that are larger than the allowed tolerances (4.10) can occur if different PHANTOMS are used compared to those used by the MANUFACTURER.
4.4 Generation of DW,REF(Z) for the water PHANTOMS
Scans of each water PHANTOM shall be used to obtain the axial images for the calculation of DWREF(Z), generated using 120 kV (or the closest available kV setting). The PHANTOMS shall be placed on the PATIENT SUPPORT (including pad) and positioned in a clinically relevant- manner without additional material in the scan field.
The CT CONDITIONS OF OPERATION and reconstruction parameters shall be suitable for
— a small water PHANTOM, and
— a large water PHANTOM.
Cardiac acquisitions, acquisitions without table movement, and shuttle mode acquisitions shall not be used. The use of AUTOMATIC EXPOSURE CONTROL shall correspond to its use in the clinical protocol selected. The reconstructed field of view shall be large enough to fully encompass the PHANTOMS.
The scan(s) shall be at least 5 cm in length and centred cross-sectionally and longitudinally on the PHANTOM. Contiguous images of approximately 5 mm nominal reconstruction thickness shall be reconstructed.
The CT CONDITIONS OF OPERATION, scan positioning, and reconstruction parameters for the scanning of each PHANTOM shall be included in the ACCOMPANYING DOCUMENTS.
NOTE Image reconstruction kernels, such as those for edge enhancement, with a non-linear relationship between the CT NUMBER and the linear ATTENUATION coefficients can adversely affect the determination of D.
4.5 Verification of Dw,REF for the water PHANTOMS
DWREF(Z) shall be calculated at each longitudinal position z. The set of DWREF(Z) values shall be compared to the corresponding outer diameter of each water PHANTOM. The two values at each position shall agree to within 7 %, for each PHANTOM size.
4.8 Generation of Dw,REF(z) for the anthropomorphic PHANTOM
Scans of the anthropomorphic PHANTOM(S) shall be used to obtain axial images for the calculation of DWREF(z). The PHANTOMS shall be placed on the PATIENT SUPPORT (including pad) and positioned in a clinically relevant-manner without additional material in the scan field. The head region of the PHANTOM shall be positioned either in the head holder or on top of the PATIENT SUPPORT. If the head region of the PHANTOM is an individual PHANTOM, it should be placed in the head holder.
The CT CONDITIONS OF OPERATION and reconstruction parameters shall correspond to the clinical protocol typically used for the relevant anatomical region; cardiac acquisitions, acquisitions without table movement, and shuttle mode acquisitions shall not be used. The use of AUTOMATIC EXPOSURE CONTROL shall correspond to its use in the clinical protocol selected. The reconstructed field of view shall be large enough to fully encompass the PHANTOM region scanned.
One continuous scan may be used to cover the entire range in the torso and its data divided accordingly.
Each of the following anatomical regions in Table 1 shall have at least 5 cm of scan coverage. The scan(s) field of view shall be centred cross-sectionally and the scan range centred longitudinally in each anatomic region. Contiguous images of approximately 5 mm nominal reconstruction thickness shall be reconstructed.IEC 62985 pdf download.
