Requests
Requests
Define a protocol for validation and
Define a protocol for validation and
prioritisation of densitometry requests.
prioritisation of densitometry requests.
Registered medical practitioners
Registered medical practitioners
In writing
In writing
Include adequate clinical information
Include adequate clinical information
Unsuitable requests should be discussed
Unsuitable requests should be discussed
with referring doctor.
with referring doctor.
Who requests a DXA scan?
Who requests a DXA scan?
GPs GPs Orthopaedist Orthopaedist Rheumatologists Rheumatologists Oncologists Oncologists Obs/Gyn Obs/Gyn Geriatricians Geriatricians Radiologists Radiologists Gastroenterologists Gastroenterologists
Adequate Clinical Information
Adequate Clinical Information
Adequate Clinical Information
GENETICS/ FAMILY HX OF FRACTURE FEMALE > MALE
POST MENOPAUSE LOW BODY MASS INDEX LOSS IN HEIGHT FRAGILITY FRACURES SMOKING/XS ALCOHOL IMMOBILITY
MEDICATIONS: CORTICOSTEROIDS INFLAMMATORY BOWEL DISEASE HYPERPARATHYROIDISM ANOREXIA
MEN WITH LOW LEVELS OF TESTOSTERONE GENETICS/ FAMILY HX OF FRACTURE GENETICS/ FAMILY HX OF FRACTURE FEMALE > MALE
FEMALE > MALE POST MENOPAUSE POST MENOPAUSE LOW BODY MASS INDEX LOW BODY MASS INDEX LOSS IN HEIGHT LOSS IN HEIGHT FRAGILITY FRACURES FRAGILITY FRACURES SMOKING/XS ALCOHOL SMOKING/XS ALCOHOL IMMOBILITY IMMOBILITY MEDICATIONS: CORTICOSTEROIDS MEDICATIONS: CORTICOSTEROIDS INFLAMMATORY BOWEL DISEASE INFLAMMATORY BOWEL DISEASE HYPERPARATHYROIDISM HYPERPARATHYROIDISM ANOREXIA
ANOREXIA
MEN WITH LOW LEVELS OF TESTOSTERONE MEN WITH LOW LEVELS OF TESTOSTERONE
DXA
DXA
““GoldGold--standardstandard””for BMD measurementfor BMD measurement Measures
Measures ““centralcentral””skeletal sites: spine and skeletal sites: spine and
hip
hip
May measure other sites: forearm
May measure other sites: forearm
Extensive epidemiologic data
Extensive epidemiologic data
Validated in many clinical trials
Validated in many clinical trials
Widely available
Widely available
Low Radiation Dose
Low Radiation Dose
DXA Technology
DXA Technology
X-ray Source
(produces 2 photon energies with different attenuation profiles)
Photons Collimator
(pinhole for pencil beam, slit for fan beam)
Patient
Detector (detects 2 tissue types - bone and soft tissue)
Very low radiation to patient. Little scatter radiation to radiographer.
Radiation in DEXA
Radiation in DEXA
Ionizing Imaging TechniqueIonizing Imaging Technique
Too much is dangerous, must be limited
Too much is dangerous, must be limited
Patients, staff and public are at risk.
Patients, staff and public are at risk.
Adherence to License issued by the R.P.I.I
Adherence to License issued by the R.P.I.I
is necessary
is necessary
Adherence to local radiological safety
Adherence to local radiological safety
regulations is necessary
regulations is necessary
ALARA (As Low As Reasonably Achievable)
ALARA (As Low As Reasonably Achievable)
Local Rules for Bone Densitometry
Local Rules for Bone Densitometry
Local rules should be drawn up by radiation
Local rules should be drawn up by radiation
safety committee /
safety committee / licence licence holder.holder.
This will help ensure compliance with the RPII
This will help ensure compliance with the RPII
licence
licence conditions.conditions.
National Osteoporosis Society (NOS) provide
National Osteoporosis Society (NOS) provide
guidelines on local rules for DEXA.
guidelines on local rules for DEXA.
These local rules should be reviewed
These local rules should be reviewed
regularly and updated.
regularly and updated.
Local Rules for Bone Densitometry
Local Rules for Bone Densitometry
(NOS)
(NOS)
Operators must never
Operators must never
expose themselves in
expose themselves in
the X
the X--ray beamray beam During a scan only
During a scan only
the patient should be
the patient should be
within the controlled
within the controlled
area
area
Local Rules for Bone Densitometry
Local Rules for Bone Densitometry
(NOS)
(NOS)
The operators desk should be placed well
The operators desk should be placed well
outside the controlled area
outside the controlled area
Equipment not in use must be switched off
Equipment not in use must be switched off
and locked
and locked
If you become pregnant you must inform
If you become pregnant you must inform
your employer / RSO.
your employer / RSO.
Hazards of Ionizing radiation
Hazards of Ionizing radiation
Cancer induction by radiationCancer induction by radiation
Genetic effects of radiation
Genetic effects of radiation
Risks are greatest for the
Risks are greatest for the foetusfoetus
Need to ensure radiation protection of both
Need to ensure radiation protection of both
staff and patients
staff and patients
Radiation Protection of staff
Radiation Protection of staff
Never irradiate yourself in the X
Never irradiate yourself in the X--ray beamray beam
Stay outside of the Controlled Area while the
Stay outside of the Controlled Area while the
patient is being scanned
patient is being scanned
Be aware that scattered radiation from the
Be aware that scattered radiation from the
patient may be significant
patient may be significant
Position work station at least 2 m from the foot
Position work station at least 2 m from the foot
end of the scanning table
end of the scanning table
If the room size is too small to allow adequate
If the room size is too small to allow adequate
distance a lead screen should be employed
Radiation Protection of staff
Radiation Protection of staff
Wear a film badge on
Wear a film badge on
the side that the
the side that the
patient is being patient is being scanned scanned Radiation doses Radiation doses received by staff received by staff
should be within laid
should be within laid
down limits down limits An operator must An operator must declare their declare their pregnancy to the pregnancy to the RPO RPO
Radiation Protection of the patient
Radiation Protection of the patient
Justify and validate all scan requests
Justify and validate all scan requests
Operator must check patient ID and ask
Operator must check patient ID and ask
about pregnancy
about pregnancy
Perform scans in a safe manner while
Perform scans in a safe manner while
ensuring that dose is ALARA.
ensuring that dose is ALARA.
Pregnancy Status
Pregnancy Status
The unborn child is at
The unborn child is at
risk of ionizing risk of ionizing radiation radiation Radiation Protection Radiation Protection in pregnancy is in pregnancy is essential essential
Pregnancy Status Protocol
Pregnancy Status Protocol
for women under 50 years
for women under 50 years
Date of patients last menstrual period is checked
Date of patients last menstrual period is checked
Ask the patient if there is chance she might be
Ask the patient if there is chance she might be
pregnant
pregnant
Record this information in writing on the request
Record this information in writing on the request
form
form
Explain to the patient that this examination
Explain to the patient that this examination
involves a relatively small dose of radiation, and
involves a relatively small dose of radiation, and
this could be harmful to her foetus if she were
this could be harmful to her foetus if she were
pregnant
pregnant
Pregnancy Status Protocol
Pregnancy Status Protocol
If LMP is not within the first ten days theIf LMP is not within the first ten days the
scan should be postponed until the
scan should be postponed until the
beginning of the next menstrual cycle
beginning of the next menstrual cycle
However However
Referring doctor may waive the LMP rule
Referring doctor may waive the LMP rule
in writing
in writing
Referring doctor may justify the exposure
Referring doctor may justify the exposure
when the benefits of scan outweigh
when the benefits of scan outweigh
radiation risks
radiation risks
Duties of Staff
Duties of Staff
Small number of highly trained operators
Small number of highly trained operators
Obtain optimum scans
Obtain optimum scans
Operate to the departmental protocols
Operate to the departmental protocols
Consistent patient positioning and scan analysis
Consistent patient positioning and scan analysis
Perform routine QC
Perform routine QC
Adequate training in ionizing radiation
Adequate training in ionizing radiation
Participate in CPD
Participate in CPD
Retain professional membership of an
Retain professional membership of an
appropriate organization such as IOS and NOS
Patient Preparation
Patient Preparation
Identify correct patient
Identify correct patient
Date of birth Date of birth Sex Sex Race Race Weight Weight Height Height
Assess pregnancy status
Assess pregnancy status
Obtain previous scans
Obtain previous scans
Remove all metal objects from areas of interest
Remove all metal objects from areas of interest
Clear explanation of scanning procedure
Clear explanation of scanning procedure
Patient questionnaire
Patient questionnaire
Patient Questionnaire
Patient Questionnaire
Identify potential risk factors forIdentify potential risk factors for
osteoporosis
osteoporosis
Details of current medication
Details of current medication
Detail of skeletal fracture history
Detail of skeletal fracture history
Identify recent Imaging examinations
Identify recent Imaging examinations
which may affect the result
which may affect the result
Identify any hip or spinal orthopaedic
Identify any hip or spinal orthopaedic
surgery/ prostheses
surgery/ prostheses
Orthopaedic prostheses
Orthopaedic prostheses
Contrast Media
Contrast Media
Identify Artifacts
Identify Artifacts
Identify prior to scanning
Identify prior to scanning
Prevents repeats and unnecessary
Prevents repeats and unnecessary
radiation
radiation
Artifacts can be a major cause of error if
Artifacts can be a major cause of error if
undetected undetected
Artifacts
Artifacts
External or anatomical External or anatomicalMetal objects such as buttons and
Metal objects such as buttons and ““body body jewellary
jewellary””
Barium/ Contrast agent
Barium/ Contrast agent
Prostheses Prostheses Hickman Line Hickman Line Aortic Calcification Aortic Calcification Paget
Paget’’s diseases disease
Patient may not always report previous surgery
Optimum Scanning
Optimum Scanning
Measure patients weight and heightMeasure patients weight and height
accurately
accurately
Identify artefacts
Identify artefacts
Record scan parameters
Record scan parameters
Use standard protocols for consistency
Use standard protocols for consistency
and comparability
and comparability
Use correct patient positioning and scan
Use correct patient positioning and scan
analysis
analysis
Ensure dose is ALARA
Ensure dose is ALARA
Protocols
Protocols
Patient Positioning Patient Positioning Scan Acquisition Scan Acquisition Scan analysis Scan analysisSkeletal Sites to Measure
Skeletal Sites to Measure
Measure BMD at both the PA spine and hip in all
Measure BMD at both the PA spine and hip in all
patients patients
Forearm
Forearm
Forearm BMD should be Forearm BMD should bemeasured under the
measured under the
following circumstances:
following circumstances:
–
– Hip and/or spine cannot be Hip and/or spine cannot be measured or interpreted measured or interpreted –
– Very obese patients (over the Very obese patients (over the weight limit for DXA table) weight limit for DXA table)
–
–
Good Positioning
Good Positioning
-
-
Spine PA
Spine PA
Straight spine in the center of the scanningStraight spine in the center of the scanning
field
field
Equal amounts of tissue on either side of
Equal amounts of tissue on either side of
spine
spine
Knees flexed over 90
Knees flexed over 90°°support pad support pad Center 1.5cms below the anterior margins
Center 1.5cms below the anterior margins
of the iliac crests in the midline
of the iliac crests in the midline
ASIS equidistant from the tabletop
DXA LUMBAR SPINE
Good positioning
Good positioning
-
-
proximal
proximal
femur
femur
ASIS equidistant from the tabletop
ASIS equidistant from the tabletop
Whole leg rotated by 25
Whole leg rotated by 25°°
Leg abducted by 15
Leg abducted by 15°°to separate ischium to separate ischium
from lesser trochanter
from lesser trochanter
Center 5cm below the greater trochanter
Center 5cm below the greater trochanter
and in the midline of the femur
and in the midline of the femur
Arms positioned away from areas of
Arms positioned away from areas of
interest
interest
Positioning devices
Positioning devices
DXA HIPS
Vertebral Fracture Assessment
Vertebral Fracture Assessment
Densitometric spine
Densitometric spine
imaging performed for
imaging performed for
the purpose of the purpose of detecting vertebral detecting vertebral fractures fractures
Indications for VFA
Indications for VFA
When BMD measurement is low, When BMD measurement is low, performance of VFA should be performance of VFA should be
considered. Clinical situations that may considered. Clinical situations that may be associated with vertebral fractures be associated with vertebral fractures include:
include:
–
–Documented height loss of greater than 2 Documented height loss of greater than 2
cm
cm
–
–History of fracture after age 50History of fracture after age 50
–
–Commitment to longCommitment to long--term glucocorticoid term glucocorticoid therapy
therapy
–
–History and/or findings suggestive of History and/or findings suggestive of
Good Positioning
Good Positioning
-
-
LVA
LVA
Use of lateral support to position spinousUse of lateral support to position spinous
processes of vertebrae parallel to the table
processes of vertebrae parallel to the table
Patient lies on left side with spine resting
Patient lies on left side with spine resting
against the support
against the support
Knees bent, arms positioned above the
Knees bent, arms positioned above the
head
head
Position lower back over curved support
Position lower back over curved support
Place pad between the knees
LVA
LVA Advantages
LVA Advantages
Assessment of vertebral Assessment of vertebral fracture status fracture status Low dose (1/100 of Low dose (1/100 of radiographs) radiographs)Visualisation of the whole
Visualisation of the whole
spine in one view
spine in one view
Short scan time
Short scan time
Use of Further Imaging
Use of Further Imaging
Overweight patients
Overweight patients ––poor image poor image resolution
resolution
Mild fractures are suspected
Mild fractures are suspected
Limited visualisation of upper thoracic
Limited visualisation of upper thoracic
spine
spine
Large discrepancy in BMD between
Large discrepancy in BMD between
vertebrae
vertebrae
AP Spine Analysis
AP Spine Analysis
Individual vertebrae falsely elevated by artifact
Individual vertebrae falsely elevated by artifact
should be removed
should be removed
Include at least two vertebrae
Include at least two vertebrae
Label the vertebrae correctly
Label the vertebrae correctly
Correctly position
Correctly position IntervertebralIntervertebralROI boxesROI boxes In elderly patients the spine scan may be of little
In elderly patients the spine scan may be of little
value if there is extensive degenerative disease
value if there is extensive degenerative disease
Bone edge markers and
Bone edge markers and intervertebralintervertebralmarkers markers may need adjusting
may need adjusting
Hip Analysis
Hip Analysis
Use femoral neck or total proximal femur,
Use femoral neck or total proximal femur,
whichever is lowest
whichever is lowest
BMD may be measured bilaterally or at
BMD may be measured bilaterally or at
either hip
either hip
Check that the leg has been rotated and
Check that the leg has been rotated and
abducted correctly
abducted correctly
Check correct position of ROI boxes
Check correct position of ROI boxes
Check that bone edge markers are
Check that bone edge markers are
correctly positioned
correctly positioned
Hip Analysis
SEVERE OSTEOARTHRITIS
OF RIGHT HIP
Interpretation
Interpretation
–
–
Good Practice
Good Practice
Use of relevant reference rangesUse of relevant reference ranges
Use of WHO guidelines
Use of WHO guidelines
Recommendations made on the lower of
Recommendations made on the lower of
the measurements at spine and hip
the measurements at spine and hip
Independent risk factors for fracture
Independent risk factors for fracture
Guidelines on management and follow
Guidelines on management and follow--upup
BMD in g/cm
BMD in g/cm22for each sitefor each site
The skeletal sites
The skeletal sites
The T
The T--score and/or Zscore and/or Z--score where appropriatescore where appropriate WHO criteria for diagnosis in postmenopausal
WHO criteria for diagnosis in postmenopausal
females and in men age 50 and over
females and in men age 50 and over
Explanation of results
Explanation of results
Risk factors including previous fragility fractures
Risk factors including previous fragility fractures
Fracture risk
Fracture risk
Unexpected results, for example a very high
Unexpected results, for example a very high
score for one vertebra which is out of context
score for one vertebra which is out of context
Indications for another imaging modality
Indications for another imaging modality
Baseline DXA Report sent to
Baseline DXA Report sent to
Doctor includes:
Doctor includes:
T
T--score/ Zscore/ Z--scorescore
Risk factors including previous nontraumatic
Risk factors including previous nontraumatic
fractures
fractures
Fracture risk
Fracture risk
Evaluation for secondary causes of low BMD
Evaluation for secondary causes of low BMD
Necessary Treatment
Necessary Treatment
Recommendations for the timing and
Recommendations for the timing and
necessity of your next BMD study
necessity of your next BMD study
Management and Follow up
Management and Follow up
Follow
Follow
-
-
up BMD Measurement
up BMD Measurement
Should only be done when the expectedShould only be done when the expected
change in BMD equals or exceeds the least
change in BMD equals or exceeds the least
significant change (LSC)
significant change (LSC)
LSC is the magnitude of change which must
LSC is the magnitude of change which must
be measured to be sure that the change is
be measured to be sure that the change is
real, not simply a result of measurement error
real, not simply a result of measurement error
Follow
Follow-
-up Scans
up Scans
Points to remember
Points to remember
Have previous scans available for review
Have previous scans available for review
Consistent patient positioning
Consistent patient positioning
Consistent scan analysis
Consistent scan analysis
Use of same software and scan compare
Use of same software and scan compare
facility
facility
Consistent approach between different
Consistent approach between different
operators operators
QA in DXA
QA in DXA
Regular scanning of Regular scanning of phantoms phantomsDaily block phantom
Daily block phantom
System calibration
System calibration
QC phantom
QC phantom
Ensures that the DXA
Ensures that the DXA
equipment is equipment is operating as precisely operating as precisely and accurately as and accurately as possible possible
QA in DXA
QA in DXA
Follow manufacturerFollow manufacturer’’s recommended IQC s recommended IQC protocol using the phantoms provided
protocol using the phantoms provided
Standard protocols for positioning
Standard protocols for positioning
phantom, acquisition and scan analysis
phantom, acquisition and scan analysis
Inspect results and report faults
Inspect results and report faults
Scanner Maintenance and Repair
Scanner Maintenance and Repair
--use of preventative maintenance programuse of preventative maintenance program
Summary
Summary
Compliance with referral guidelines
Compliance with referral guidelines
Benefits of exam must outweigh radiation risks
Benefits of exam must outweigh radiation risks
Careful consideration of appropriate technique
Careful consideration of appropriate technique
Operators should ensure that no person is
Operators should ensure that no person is
exposed to radiation more than is reasonably
exposed to radiation more than is reasonably
necessary
necessary
Consideration of frequency of follow up scanning
Consideration of frequency of follow up scanning
Radiation protection in pregnancy is essential
Radiation protection in pregnancy is essential
Use common sense: time, distance, shielding
Use common sense: time, distance, shielding
Useful Information
Useful Information
www.ios.ie www.ios.ie www.nos.org.uk www.nos.org.uk www.iscd.org www.iscd.org www. www.osteoporosis.caosteoporosis.ca www.osteofound.org www.osteofound.org www.nice.org.uk www.nice.org.ukRoyal college of Physicians, UK
Royal college of Physicians, UK
Osteoporosis International Journal