among patients and variability in manifestations of diseases and injuries
2 require
physicians to deviate frequently from standardized procedures. For instance, this
kind of medical adaptation lies in every surgical procedure, where innovations are
being made daily as an individual surgeon finds improved results with specific
changes in operative technique (Moore, 1969; Moore, 2000). Similarly, radiologists
and technologists, operating complex medical imaging devices such as computed
tomography (CT) and magnetic resonance imaging (MRI), change acquisition
parameters, use advanced visualization tools, and constantly improve those to
adapt to patient variability (Takahara et al., 2004; Sablayrolles, 2002). Such innovative medicine is a departure from the routine and established practice of routine,
producing better patient outcomes.
At the early stage of the computed tomography (CT) development, the X-ray tube
rotated around the patient and acquired one slice. Then the table moved, while the
X-ray tube and detector went back to their initial position, in order to get the next
slice of the patient (Trajtenberg, 1990). In 1990s, Willi Kalendar and Kazuhiro
Katada introduced helical computed tomography devices, allowing a complete
freely rotating motion of the X-ray tube/detector couple around the patient.
3 The
table moves while the X-ray tube/detector rotates, resulting in a helical path of the
X-ray beam. The slip rings for data transfer and the power supply miniaturization
were the key technology enablers for helical CTs. In 1993, the Elscint Company
(Haifa, Israel) introduced a dual-detector ring, with a complete rotation in a second:
the multi-slice CT was born, with the beginning of the race to higher rotation speed
and multiple detector rings (2, then 4, then 8). In 2000, the multi-slice CTs were
widely distributed as dual-slice CT, four-slice, and eight-slice CT systems. The
number of slices is originated by the number of detector lines receiving the X-ray
beam, associated with a pivotal characteristic, the sickness of detector lines. Rapid
improvement of both characteristics nowadays reveals numerous options for manufacturers for new product development.
Unlike CT, magnetic resonance imaging (MRI) uses no ionizing radiation but a
powerful magnetic field (measured in Tesla) to align the nuclear magnetization of
hydrogen atoms in water in the patient body. Consequently, MRI provides much
more contrast between the different soft tissues of the body than CT does. This
medical imaging device is primarily useful in neurological (brain), musculoskeletal
(joint), cardiovascular. As it examines chemical and physical properties at the cell
level, MRI provides a new means for early detection of disease in care areas such as
oncology (cancers) and neurology (neurological degenerative diseases).
4
2 To illustrate this variety, we refer to the measure of disability adjusted life years (DALYs) by cause
of death, as shown in the Appendix A.
3 A useful, more detailed history of this technological development can be found in a PDF document
named CT History Technology, accessed at http://www.medical.siemens.com/ siemens/ zh_CN /
gg_ct_FBAs /files/brochures/ CT_History_and_Technology.pdf on February 2, 2009.
4 For readers with a deeper interest on this promising medical imaging device, we recommend to
access the international journal of basic research and clinical applications dedicated to MRI,
Magnetic Resonance Imaging, edited by Elsevier.
104
J. Galbrun
2 require
physicians to deviate frequently from standardized procedures. For instance, this
kind of medical adaptation lies in every surgical procedure, where innovations are
being made daily as an individual surgeon finds improved results with specific
changes in operative technique (Moore, 1969; Moore, 2000). Similarly, radiologists
and technologists, operating complex medical imaging devices such as computed
tomography (CT) and magnetic resonance imaging (MRI), change acquisition
parameters, use advanced visualization tools, and constantly improve those to
adapt to patient variability (Takahara et al., 2004; Sablayrolles, 2002). Such innovative medicine is a departure from the routine and established practice of routine,
producing better patient outcomes.
At the early stage of the computed tomography (CT) development, the X-ray tube
rotated around the patient and acquired one slice. Then the table moved, while the
X-ray tube and detector went back to their initial position, in order to get the next
slice of the patient (Trajtenberg, 1990). In 1990s, Willi Kalendar and Kazuhiro
Katada introduced helical computed tomography devices, allowing a complete
freely rotating motion of the X-ray tube/detector couple around the patient.
3 The
table moves while the X-ray tube/detector rotates, resulting in a helical path of the
X-ray beam. The slip rings for data transfer and the power supply miniaturization
were the key technology enablers for helical CTs. In 1993, the Elscint Company
(Haifa, Israel) introduced a dual-detector ring, with a complete rotation in a second:
the multi-slice CT was born, with the beginning of the race to higher rotation speed
and multiple detector rings (2, then 4, then 8). In 2000, the multi-slice CTs were
widely distributed as dual-slice CT, four-slice, and eight-slice CT systems. The
number of slices is originated by the number of detector lines receiving the X-ray
beam, associated with a pivotal characteristic, the sickness of detector lines. Rapid
improvement of both characteristics nowadays reveals numerous options for manufacturers for new product development.
Unlike CT, magnetic resonance imaging (MRI) uses no ionizing radiation but a
powerful magnetic field (measured in Tesla) to align the nuclear magnetization of
hydrogen atoms in water in the patient body. Consequently, MRI provides much
more contrast between the different soft tissues of the body than CT does. This
medical imaging device is primarily useful in neurological (brain), musculoskeletal
(joint), cardiovascular. As it examines chemical and physical properties at the cell
level, MRI provides a new means for early detection of disease in care areas such as
oncology (cancers) and neurology (neurological degenerative diseases).
4
2 To illustrate this variety, we refer to the measure of disability adjusted life years (DALYs) by cause
of death, as shown in the Appendix A.
3 A useful, more detailed history of this technological development can be found in a PDF document
named CT History Technology, accessed at http://www.medical.siemens.com/ siemens/ zh_CN /
gg_ct_FBAs /files/brochures/ CT_History_and_Technology.pdf on February 2, 2009.
4 For readers with a deeper interest on this promising medical imaging device, we recommend to
access the international journal of basic research and clinical applications dedicated to MRI,
Magnetic Resonance Imaging, edited by Elsevier.
104
J. Galbrun