MRTs ensure radiopharmaceutical doses are appropriate and accurate
Importance of accurate dosing
- An accurate dose is defined as the appropriate radiopharmaceutical selection that falls within the limits of ±10% of the prescribed dose that is set by institutional policies and procedures.1
- Accurate radiopharmaceutical dose is important for1:
- the quality of the procedure to ensure appropriate dose for the desired therapeutic or diagnostic outcome,
- reproducibility of studies for patients requiring follow-up imaging, and
- patient safety.
- The radiopharmaceutical dose administered to the patient reflects the balance between optimal study/therapy and patient safety.2
- The dose is kept as low as reasonably achievable (ALARA) to obtain the optimal diagnostic/therapeutic outcome for the patient.
- Administration of a dose below the minimum of the recommended range for a procedure can lead to a suboptimal study, compromise reproducibility, and require the exam to be repeated.
- Administration of a dose above the maximum of the recommended range will increase radiation exposure to the patient and does not correlate with improvements in study outcomes or diagnostic information in most circumstances.
- MRTs consistently assess radiopharmaceuticals prior to administration to patients to ensure the dose and product being given is accurate for the study proposed, including3,4:
- The quantity of radioactivity to be administered reflects the dose prescribed (either individually by prescription or in a standard protocol).3,4
- Radioactive decay calculations confirm the volume necessary to deliver the prescribed radioactive dose.2
- MRTs ensure a radiopharmaceutical is not being used beyond the manufacturer’s recommended expiration date/time unless specific quality control testing demonstrates that the product still meets applicable specifications at the time of use.5
- MRTs ensure adherence to a regular quality assurance program on all equipment responsible for calculating accurate patient doses (i.e., dose calibrator, INTEGO PET infusion system).
- The dosage of radiopharmaceuticals given in therapeutic procedures should be verified by a second MRT or physician prior to administration.6
- MRTs follow dose charts and make dose adjustments based on patient factors, including:
- patient body habitus (usually ±10% of prescribed dose);
- pregnancy (a lower dose for pregnant women may be advised by the supervising radiologist or physician7; MRTs can consult the SNMMI Nuclear Medicine Radiation Dose Tool as needed); and
- pediatric patients (doses reduced based on weight, taking into consideration department-set minimums for pediatric patients).
- Documentation in the patient’s record (in accordance with the requirements established by each facility) may include3,4:
- name of MRT or physician administering dose,
- study performed,
- date and time,
- radiopharmaceutical administered,
- administered dose,
- route/site of administration,
- difficulties encountered (e.g., interstitial administration),
- deviations from standard procedure.
- It is the MRT’s responsibility to document/report inaccurate dosing (by themselves or by others) that they are aware of through the appropriate mechanisms (i.e., report to the RSO).
- Statkiewicz Sherer MA, Visconti P, Ritenour ER, Welch Haynes K. Radiation protection in medical radiography. 7th ed. Mosby Elsevier; 2015. Accessed August 7, 2020. https://www.elsevier.com/books/radiation-protection-in-medical-radiography/statkiewicz-sherer/978-0-323-17220-2
- ICRP. The 2007 recommendations of the International Commission on Radiological Protection. ICRP publication 103. Ann ICRP. 2007;37(2-4):1-332. doi:10.1016/j.icrp.2007.10.003
- American College of Radiology and Society of Nuclear Medicine. ACR-SNM technical standard for diagnostic procedures using radiopharmaceuticals. Published online 2011. Accessed August 8, 2020. https://s3.amazonaws.com/rdcms-snmmi/files/production/public/docs/ACR-SNM_Technical_standards_for_diagnostic_procedures_using_radiopharmaceuticals_1382731756580_2.pdf
- Force S-TS of PT. Nuclear medicine technologist scope of practice and performance standards. J Nucl Med Technol. 2017;45(1):53-64.
- Callahan RJ, Chilton HM, Ponto JA, Swanson DP, Royal HD, Bruce AD. Procedure guideline for the use of radiopharmaceuticals 4.0. J Nucl Med Technol. 2007;35(4):272-275. doi:10.2967/jnmt.107.044156
- Australian Radiation Protection and Nuclear Safety Agency. Safety guide: Radiation protection in nuclear medicine.; 2008. Accessed August 8, 2020. https://www.arpansa.gov.au/sites/default/files/legacy/pubs/rps/rps14_2.pdf
- Bural GG, Laymon CM, Mountz JM. Nuclear imaging of a pregnant patient: Should we perform nuclear medicine procedures during pregnancy? Mol Imaging Radionucl Ther. 2012;21(1):1-5. doi:10.4274/Mirt.123