Nuclear Medicine Flashcards
What is it?
application of radioactive substances in diagnosis and treatment of disease
what is a radiopharmaceutical?
radionuclide + pharmaceutical
what is technetium?
has a half-life of 6 hours. produced by decay of molybdenum-99 which has a half life of 2.8 days
what is the technetium-99m generator?
99Mo is absorbed on alumina in a sterilised glass column surrounded by lead shield. Tc-99m is eluted from the alumina column by an ion exchange mechanism when sterile saline is passed through it. elate is sodium pertechnetate NaTcO4
what are the QC processes for radionuclides?
=percentage of total activity that is present in the stated radionuclide form. could possibly be contaminated with 99Mo from the generator. do a daily test for molybdenum breakthrough in the eluate.
what are the QC processes for radiochemicals?
=percentage of activity present in stated chemical form. contaminant in TC-99M labelled radiopharmaceuticals is unbound pertechnetate and is measured using chromatography
what are the QC processes for chemical purity?
=percentage of total mass that is present in the stated chemical form. possible contamination is AL3+ from the alumina (Al2O3) column in the generator. aluminium concentration is tested on the first elution of the generator.
what is a gamma camera?
The radiopharmaceutical emits gamma rays and is imaged in a scintillation crystal using a collimator.
gamma rays are converted into light within the scintillation crystal.
an array of photomultiplier tubes at the rear of the crystal transforms the light into electrical signals
what are the 3 types of planar imaging?
static imaging: used where distribution of radiopharmaceutical is changing very slowly.
dynamic imaging: used where radioactivity of area is changing rapidly
gated imaging: used to image organs with regular with regular physiological motion
what is spect?
3D image. improves image contrast. transracial slices can be reconstructed
what is spect/ct?
hybrid imaging allows for fusion of nuclear medicine images with CT images.
what is PET?
Positron emission tomography using F-18.
what is radionuclide therapy?
I-131: thyroid disease, thyroid cancer, NETs
P-32: myeloproliferative disease
Sr-89: for palliation of bone pain
what radiation protection laws are applied in NM?
time, distance, shielding. inverse square law (doubling the distance from the source reduces the dose to 1/4), syringe shells, lead-lined things.
what legislation is relevant in NM?
Health and Safety at work Act 1974, IRR 207, IR(ME)R 2017, the environmental permitting regulations 2016, the carriage of dangerous goods and sue of pressure equipment regulations 2009
how are nuclear medicine scans different to X-ray scans?
X-rays provide detailed images of bones useful for detecting fractures, dislocations and density changes. Nuclear medicine bone scans provide functional information about bone metabolism and blood flow. They detect areas of increases bone turnover such as that seen in metastatic bone disease, infections and stress fractures.
Nuclear medicine scans are more sensitive for detecting certain conditions such as early metastases or areas of bone inflammation compared to xrays but x-rays are show more detailed anatomical information and are used as first-line imaging modalities
What are the differences in radiation protection measures that need to be taken by staff and patient when comparing nuclear medicine to standard x-ray?
i. Nuclear medicine:
1) Staff protection: staff handling (PPE) such as gloves. Lead syringe shields. Distance, time shielding. Facilities are shielded.
2) Patient protection: may be advised to drink plenty of fluids to help flush tracer out. Radiotracer is usually ALARP and justified. Given advice about when to return to work, what to do with urine etc.
ii. X-ray:
1) Staff protection: stand behind protective barriers to minimize exposure to scattered radiation. Lead aprons, thyroid collars and lead glasses may be worn by staff.
2) Patient protection: wear lead aprons or shielding devices to minimize radiation to sensitive organs. Radiographers use appropriate collimation and exposure settings to minimise unnecessary radiation exposure
how would you ensure that environmental contamination had not occurred?
i. Regular contamination monitoring
ii. Proper handling procedures and storage
iii. Routine surface monitoring
iv. Personal monitoring
vi. Training and education
what would you do if there was contamination?
1) Isolate the area
2) Notify radiation protection supervisor and radiation protection advisor.
3) Containment and clean up
4) Investigation and root cause analysis
5) Documentation and reporting
What do you need to consider if setting up new nuclear medicine department in terms of radiation protection?
a. Regulations
b. Shielding
c. Monitoring
d. Radiation safety training
e. Personal protective equipment
f. Patient dose optimisation
g. Radiopharmaceutical handling
h. Radiation emergency preparedness
i. Quality assurance and quality control
j. Patient education
