Nuclear Medicine - types, prep, +, -

What do the radiopharmaceuticals do in an NM Bone Scan

target bones

Who would get a whole body bone scan

people with bone mets, RA, OA

When is NM bone scan used in a specific area and what is usually used

?#, assessment of known area of degeneration/fusion, e.g. ankle joint pre surgery

Usually using SPECT CT (fusion of the NM image and CT)

What’s given in an NM bone scan

Pt is injected with radiopharmaceutical specifically tailored to be absorbed by the bones i.e. phosphates

What radiopharmaceutical is used in NM bone scan

Tc99m DPD (Dicaboxypropane diphosphonate)

4 applications of NM bone scan

• Oncology

• Inflammatory and metabolic bone diseases

• Trauma

• Infection

what other two terms are used for myocardial perfusion imaging

cardiac scintigraphy, cardiac stress/rest scan

what does radiopharmaceutical in cardiac stress/rest scan target

targets mitochondria in the myocardium showing blood flow/perfusion to that area

Who would a myocardial perfusion imaging be done in and why

pts who have symptoms of cardiac ischaemia/myocardial infraction - to determine if they need intervention i.e. CABG

Step 1 of cardiac scintigraphy

Pt is stressed (heart undergoing stress/reduction in oxygen and blood supply)

Step 2 of cardiac scintigraphy

Pt is injected with radiopharmaceutical that will travel to the cardiac muscle and taken in by the normal muscle

Step 3 of cardiac scintigraphy

Radiologist will look for any areas that do not take in radiopharmaceutical bc this will show diminished blood supply/ischaemia

Step 4 of cardiac scintigraphy

Test is repeated without stress to see if ischaemia is only present during exertion and is therefore treatable with drugs etc.

Why do renal imaging?

radiopharmaceutical targets collecting systems - showing urinary/renal output

differentiation between obstructed vs non-obstructed hydronephrosis

Procedure of renal imaging

• radiopharmaceutical collects in pelvis of kidney

• then excreted

• pt given diuretic to see up and observe reaction of kidney

• if obstructed diuretic will have little effect

What is generated after a renal imaging and what does it show

Time curve generated - show function/output over duration of scan - curve shape determines diagnosis.

What else can be determined in renal imaging

Relative function of each kidney

4 benefits of RNI

• Shows function/metabolic action of cells and organs/systems

• Determines relative function of regions within organ

• Determines presence and site of normal vs ectopic/abnormal disease

• Organ specific

2 contraindications of RNI

• Pregnancy - not an absolute contraindication

• Bio-distribution altering medications which affect the efficacy of the radiojlabel or in cases of abnormal anatomy

4 patient care instructions

• Come hydrated

• Pts may have to stop medication - examination specific

• Asked to be accompanied by no more than one adult

• If breast feeding - stop for a specific period

How long until renal imaging takes place after radiopharmaceutical is administered

immediate and scan dynamically for 20 mins

How long until lung imaging takes place after radiopharmaceutical is administered

within 10 minutes post IV for perfusion imaging

How long until bone imaging takes place after radiopharmaceutical is administered

wait 2/3 hours post IV to investigate bony metastases

RNI examination procedure

• Pt lies on an imaging table with gamma camera above and below pt

• Cameras moved as close as possible imaging with the camera stationary or moving

• Pt must remain extremely still, some examinations take up to 45 minutes

Outpatient post care

• Hydration and emptying of bladder

• Avoid contact with young children

Inpatient post care

• Information sheet sent to ward

• Any body fluid spillages are radioactive for 24hrs, warn staff

• Avoid contact with large numbers of staff/visitors etc for 24hrs (Tc^99m)

Benefits of RNI over skeletal x-ray

• Early detection

• Early treatment

• Higher success rate

When would you use X-ray over RNI

• If 50% loss of bone mineral content

• If lesion is greater than 1.5cm

What are the 3 benefits of xray over RNI

• Lower cost

• Lower radiation dose

• Speed of diagnosis

What are the benefits of RNI over xray

• Reflects metabolic bone reaction to disease process - neoplastic, traumatic, inflammatory

• Greater sensitivity - but sometimes poor specificity

• 6-12 month lead time (can detect abnormal bone activity 6-12 months before lesion becomes visible on xray)