Chorionic Villous Sampling
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A child consuming breast milk from a patient who has had a nuclear medicine study might receive an unnecessary radiation dose if there has been insufficient time between the nuclear medicine study and breast-feeding. Similarly, children in close contact with the patient might receive an unnecessary radiation dose.
It is only the radioactivity of the breast milk that is an issue; the other components of the radiopharmaceutical, from diagnostic nuclear medicine studies, are not considered harmful. Once the radioactivity has reduced, the breast milk can be consumed normally by the baby.
In the table below:
The following table is a summary of advice regarding the need to restrict close contact with an infant and/or the need to interrupt breast-feeding to ensure that the infant receives a total effective dose (from both external and internal irradiation) of no more than 1 mSva.
|Test||Radiopharmaceutical||Advice to patient concerning the need to restrict close contact with a childb||Advice to patient concerning the need to interrupt breastfeedingc|
|PET||18F-FDG||Not required||1 hr interruption|
|Gallium||67Ga-citrate||Restrict contact for 3 days||Cessation1|
|Lung perfusion||99mTc-MAA||Not required||13 hr interruption|
|Bone||99mTc-MDP or HDP||Restrict contact for 1 hr||1 hr interruption|
|Heart , tumour or parathyroid||99mTc-MIBI||Restrict contact for 4 hr||4 hr interruption|
|Thyroid||99mTc-pertechnetate||Not required||26 hr interruption|
|Meckel’s diverticulum||99mTc-pertechnetate||Not required||34 hr interruption|
|Red blood cell label||99mTc-PYP||Not required||2 hr interruption|
|In vitro in vivo labelled||99mTc-red cells||Restrict contact for 2 hr||12 hr interruption|
|Heart||99mTc-tetrofosmind||Restrict contact for 4 hr||4 hr interruption|
|Infection/inflammation||99mTc-white cellse||Not required||24 hr interruption|
|Tumour||111In-octreotide||Restrict contact for 42 hr||45 hr interruption|
|Tumour||123I-MIBGf||Not required||22 hr interruption|
|Thyroid||123I-sodium iodide||Not required||6 hr interruption|
|Perfusion imaging||125I-HSA||Not required||6 day interruption|
|131I-sodium iodide||Restrict contact for 6 hr||Cessation|
|Heart or tumour||201Tl-chloride||Not required||15 hr interruption|
Modified from: ARPANSA – Radiation Protection Series No 14.2. Date of publication: 8 August 2008 pgs 31-32.
aOther agents do not require restriction of contact with small children or interruption of breast-feeding. These include those agents used for white cell scans (99mTc-colloid), biliary scans (99mTc-DISIDA or HIDA), renal scans (99mTc-DMSA or 99mTc-DTPA or 99mTc-MAG3), GFR estimation (51Cr-EDTA), lung (ventilation only) scans (99mTc-aerosol or Technegas) and 111In-white cell scans.
a. This table gives estimates of the minimum close contact restriction or interruption period required to limit the dose to less than 1 mSv. Where the restriction or interruption period calculated is very short (e.g. for 18F-FDG), or is indicated as not required, it might be prudent to apply a restriction or interruption period of at least 4 hours for ALARA (as low as reasonably achievable) purposes.
b. Takes into account external exposure from the patient only. The contact restriction times specified are post-administration (i.e. the time lapse from the time the radiopharmaceutical is administered to the patient to the resumption of normal contact). Concentration of radioactivity is measured in kilo Becquerels per millilitre.
c. Takes into account both external exposure from the mother, and internal dose from ingested milk. The interruption periods specified are post-administration.
d. There is a lack of scientific data relating to the uptake and clearance of 99mTc-tetrofosmin from breast milk. For the purposes of these calculations, it has been assumed that its behaviour in vivo is similar to that of 99mTc-MIBI.
e. Assumes a labelling efficiency of greater than 75%.
f. Assumes the chemical species appearing in the breast milk is 123I-sodium iodide.
1Available from ARPANSA web site: www.arpansa.gov.au/publications/codes/rps14_2.cfm
Page last modified on 21/7/2017.
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