1. health and fitness
2. disease
3. cancer

Hybrid SPECT/CT
imaging, do we really
need it?
Sue Rattray
¾ What is SPECT/CT
¾ How it works
¾ Interesting case
examples
Nuclear Medicine Technologist
Princess Alexandra Hospital
Brisbane
Australia
What is SPECT/CT?
¾ Comparing the functional images
of Nuclear Medicine with the
more anatomical modalities like
CT has been done in the past
with sideside-byby-side comparison
techniques or by the use of
software based fusion, overlaying
the two sets of data information.
Hybrid SPECT/CT Provides:
Why Hybrid?
¾ Following the success of hybrid
PET/CT, hybrid SPECT/CT can
combine the functional imaging
capabilities of SPECT with the
precise anatomical overlay of CT
images, all performed in the one
imaging session.
Attenuation Correction
¾ Correcting for tissue attenuation
¾ Precise IMAGE FUSION for
anatomical referencing.
¾ Accurate patient specific
ATTENUATION CORRECTION,
CORRECTION,
giving better localisation and
definition of organs and lesions,
resulting in more accurate
diagnoses and improved patient
management
requires an accurate
measurement of the spatial
distribution of attenuation
coefficients within the patient.
¾ The Hounsfield units from CT data may be
used for this, giving improved statistical
information, and greater confidence in
detection of abnormalities within deeper
organs.
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Myocardial Perfusion Scan Uncorrected
Short Axis
Short Axis
Vertical Long Axis
Horizontal Long Axis
Short Axis
Short Axis
Vertical Long Axis
Horizontal Long Axis
Image Fusion
Vertical Long Axis
Uncorrected
Corrected for Tissue Attenuation and Scatter
Corrected
¾ Also called image registration or
functional anatomical mapping
(FAM).
¾ Hybrid systems will provide precision
alignment of the two sets of image
data and eliminate inaccuracies
caused by variations in patient
position, couch surfaces and the
internal changes within the patient
from one imaging session to the next.
Vertical Long Axis
Hybrid SPECT/CT systems
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Multislice hybrid SPECT/CT system (Siemens Medical
Systems brochure.)
Hybrid SPECT/CT systems
¾ Studies have shown SPECT/CT to
benefit in the management of patients
with a variety of clinical conditions
¾ In Oncology, to localise tumour sites,
assess invasion into surrounding tissues
and demonstrate their functional status
¾ Quality CT images allow Radiologists to
compare structural detail with isotope
activity, potentially giving a differential
diagnosis with no further imaging.
The range of clinical applications includes
¾ Myocardial Perfusion – Tc99m Sestamibi,
Tc99m Myoview or Thallium201
¾ Skeletal – Tc HDP or MDP
¾ Neuroendocrine – In111 Octreotide
¾ Adrenal – I123 MIBG
¾ Lymphomas and Infections – Gallium67
¾ Sentinel Node mapping – Tc Colloid
¾ Parathyroid Adenomas – Tc MIBI
¾ And many more…
more…..
Case Examples
¾ In over 12 months of use we have
encountered many interesting cases,
some merely unusual, but a large number
where the additional information provided
by hybrid imaging has either changed or
vastly improved upon the quality of the
diagnosis.
Anterior and Posterior Whole body bone scan (2 intensities)
Procedure – Bone Scan
¾ Patient with history of Breast
Carcinoma, and low back
pain.
¾ Dose of 865 MBq Tc99m HDP
given.
¾ Delayed whole body and spot
views of ribs and skull plus
SPECT imaging and low dose
nonnon-diagnostic CT of Lumbar
Spine for lesion localisation.
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3 view display SPECT, CT and fused
Transverse SPECT slices at L5/S1
SPECT/CT Fusion
Outcome - Localisation of activity in
the Lumbar spine
¾
¾
SPECT/CT fusion images
distinguished facet joint
arthropathy from Pars
fractures therefore targeting
the treatment outcomes
Also indicated that
metastases from the breast
primary were unlikely.
Zoomed CT slice
Procedure – Bone Scan
¾ 17 yr old female with increasing low back
pain and raised ESR.
¾ Dose of 802 MBq Tc99m HDP given.
¾ Three phase bone scan of the spine and
pelvis, plus SPECT imaging and low dose
nonnon-diagnostic CT of Lumbar Spine for
lesion localisation.
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Planar static views
3 view display SPECT, CT and fused
Findings
¾ Marked increased uptake is seen just to
the left of midline and centred on L3.
¾ SPECT images locate the foci to the
spinous process on the left and posterior
to the facet joint of L3/4.
¾ CT shows the joint and spinous process
are unchanged, with the lesion lying within
the left Para spinal muscle.
SPECT Transverse slices
Magnified CT slice with calcification in soft tissue
¾ MRI showed an enhanced lesion on T1
and T2 suspicious of an infective process.
¾ A Biopsy performed under fluoroscopy
was inconclusive.
¾ FollowFollow-up MRI was more in keeping with a
Benign Heterotropic ossification or
Myositis Ossificans
¾ CT found the ossification to have
progressed, with an increase in size, but
no aggressive features were
demonstrated.
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T2 weighted MRI
Repeat CT scan at 5 months
Anterior and Posterior Whole body bone scan (2 intensities)
Procedure – Bone Scan
¾
¾
¾
Patient with a history of Prostatic
Cancer and a PSA of 15, ?
Metastases.
Dose of 843 MBq Tc99m HDP
given.
Delayed whole body and spot views
of ribs and skull plus SPECT
imaging and low dose nonnondiagnostic CT of Lumbar Spine for
lesion localisation.
Planar static views
SPECT Transverse slices
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3 view display SPECT, CT and fused
Findings
¾
¾
Small area of intense uptake at the
right inferior sacrum, localised to a
sclerotic lesion on the fusion CT,
consistent with skeletal metastases.
Degenerative uptake in the right
shoulder joint, mid and lower
lumbar spine, both knees and the
left wrist.
CT slice of Sacrum
Procedure – Bone Scan
¾ 85 yr old patient with a history of Prostatic
Cancer and a rising PSA ? Metastases.
¾ Dose of 843 MBq Tc99m HDP given.
¾ Delayed whole body and spot views of
ribs, skull and pelvis, plus SPECT imaging
and low dose nonnon-diagnostic CT of Pelvis
for lesion localisation.
Planar static views – Lateral Pelvis
Anterior and
Posterior
Whole body
bone scan
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SPECT Transverse slices
3 view display SPECT, CT and fused
CT slices of Pelvis
CT slices of Pelvis
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Findings
White Blood Cell labelled scan of
Polycystic Kidneys
¾ Degenerative changes in cervical and lumbar
spine
¾ Paget’
Paget’s disease in right hemipelvis
¾ Bladder diverticulum within a right inguinal
hernia
¾ No evidence of metastatic disease
¾ Patient received 809 MBq Tc 99m
Labeled autologous white blood
cells.
¾ One hour and three hour planar
images were performed, with
SPECT/CT imaging of the
abdomen for lesion localization.
3 view display SPECT, CT and fused
3 hour Static images
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Findings
Procedure – Gallium 67 scan
¾ There is no abnormal tracer uptake in
the kidneys.
¾ Low grade tracer uptake in the
stomach and thyroid gland likely
artifact from free Pertechnetate.
¾ Note is made of the kidney and liver
disease on the CT scan.
¾ Patient presented with left otitis
externa, suspected osteomyelitis
left temporal bone and facial nerve
palsy.
¾ A three phase bone scan was
performed, followed by a Gallium67
infection study.
Bone scan - Transverse slices
Planar static views
Blood Pool
2 hr Bone
48 hr Ga67
Findings – Bone Scan
Gallium 67 Coronal and Transverse slices
¾ Moderate increased tracer uptake at the
left base of skull likely osteomyelitis.
osteomyelitis.
¾ CT localised the activity to the left mastoid
process, and ruled out Pagets.
¾ Other skeletal activity attributed to Pagets’
Pagets’
disease
¾ Low grade activity also seen on the
Gallium scan.
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3 view Gallium fusion images 3 months
repeat
¾ A repeat Gallium scan at 3 months
after intensive antibiotic therapy
showed only very mild uptake in the
region of the left mastoid.
Procedure – Parathyroid Scan
Technique
¾ Patient received 831 MBq Tc 99m
¾ 39 yr old female with hypercalcaemia
secondary to hyperparathyroidism
¾ 5 days post caesarean section.
¾ Scheduled for urgent surgery.
Pinhole and Planar images of neck and
chest
Sestamibi and 196 MBq Tc99m
Pertechnetate.
¾ Early and delayed planar images were
performed.
¾ SPECT imaging and low dose non
diagnostic CT was performed of the neck
and chest for lesion localization.
3 view display SPECT, CT and fused
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Zoomed CT image
Findings
¾ A large focus of increased uptake related
to the upper pole of the right thyroid is
present on all phases of imaging
¾ CT correlates this with a corresponding
low density lesion of approximately 2cm
diameter in the right paraoesophageal
groove.
Procedure – In111 Octreotide scan
¾ Follow up scanning for patient with known
metastatic Gastrinoma
¾ 151MBq Indium111 Octreotide given
¾ Whole body and abdomen images
obtained at 4 and 24 hours
¾ SPECT/CT of the chest and abdomen
Transverse SPECT slices
4 hour
Planar
statics
SPECT / CT fused Transverse slices
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Findings
¾ Multiple sites of Octreotide avid disease in
the Liver, showing progression from the
previous studies
¾ SPECT/CT localises these areas, but also
demonstrates one lesion on the CT which
is not avid for Octreotide, a PET scan was
recommended.
Sentinel Lymph node study
Static images – immediate and
delayed
¾ Patient with known melanoma in the right
posterior auricular region
¾ 20MBq Tc99m Antimony Sulphur Colloid
given in four intraintra-dermal injections
¾ Early and delayed static imaging
performed, plus SPECT/CT of the head
and neck.
3 view display SPECT, CT and fused
Triangulation of SPECT and CT
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Findings
Incidental findings on SPECT/CT
scans
¾ Moderate tracer uptake seen on the right,
slightly inferiorly to the injection site
¾ The diagnostic quality of the CT portion of
¾ SPECT/CT localised this to a 5x3 mm
the imaging process allows visualisation of
other structural abnormalities, most often
normal variants or pre existing
pathologies.
¾ However, these must still be commented
upon in the reporting
infrainfra-parotid node, posterior to the
mandible
¾ Marked on the skin with ink.
CT for Myocardial Perfusion study –
cysts in liver
Calcified Plaques typical of Asbestosis
Surgical clips in resected Liver Secondaries
Bone Scan – Patient
with low back pain
showed uptake in
posterior ribs
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Large mass in Rt lower lobe
Practical Implications
¾ Costs
¾ Space
¾ Radiation Protection
¾ Staff training
¾ Projected uses
AAA
Acknowledgments
¾ Greg Rattray – my husband, for allowing
me to pick his brains
¾ Dr. Stanley Ngai – for his help with CT
interpretation
¾ Michelle Jenkins – for access to her
collection of interesting cases.
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References
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CT/SPECT scanner installation PAH Department
Keidar Z, Israel O, Krausz Y, 2003. SPECT/CT in
Tumour Imaging: Technical Aspects and Clinical
Applications. Seminars in Nuclear Medicine 33(3):p205
O’Connor, M and Kemp, B, 2006. SingleSingle-Photon
Emission Computed Tomography/ Computed
Tomography: Basic Instrumentation and Innovations.
Seminars in Nuclear Medicine 36(4), p256p256-266.
Schillaci O, Danieli R, Manni C, Simonetti G, 2004. Is
SPECT/CT with a hybrid camera useful to improve
Scintigraphic imaging interpretation? Nuclear Medicine
Communications 25(7): p705p705-710.
Griffiths M, Lee A, 2006. SPECT/CT hybrid imaging:
Technology, techniques and clinical experience. Synergy
Jan 2006 p20p20-27.
PAH Department installation console area
Come to Australia for
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“Tomorrow and Beyond: Connecting and Communicating”
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9 – 12 September, 2010
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