F18-FDG PET/CT Patient Preparations, Precautions, and Safety

1. Tumor diagnosis

2. Staging

3. Restaging

4. Treatment monitoring

5. Radiation Therapy (RT) planning

In clinical practice, 18F-FDG PET/CT is commonly used in the evaluation and management of many types of cancer, including:

4 to 6 hours; 6 hours

Recommend complete fasting for _________ (SNMMI) or minimum of __________ (EANM) before the radiotracer injection

Fasting

To minimize dietary glucose–related competitive inhibition of 18F-FDG uptake and reduce serum insulin to near basal levels

good hydration

Most guidelines recommend ___________, typically oral, before the study for radiation safety reasons and to ensure a low 18F-FDG concentration in urine. 

1 L

(EANM) ___ of water by mouth in the 2 h before injection and favors another 0.5 L during the uptake period as tolerated

2–3 12-oz (355 mL each) glasses

(NCI) at least ______________ of water during fasting and another 250–500 mL of water after injection and before scanning 

1–2 L

(SNMMI) patients drink _________ of plain water as tolerated during the 4 h immediately before the PET/CT scan

high-protein, low-carbohydrate diet

recommend a ___________________ for 24 hours before scanning to minimize dietary glucose–related competitive inhibition of 18F-FDG uptake 

12 hours

Alcohol and nicotine products are completely avoided for __________ before the scan

24 H

Recommend that exercises such as jogging, cycling, weightlifting, strenuous housework, yard work, and sexual activity be avoided for a minimum of ____ (ideally 48 h) before the scan to minimize uptake of radiotracer in skeletal muscles

6 h

The EANM suggests that all patients avoid (extreme) exercise for at least ____ before the PET study.

24 h

Both the NCI and the ACR recommend avoiding strenuous activity for _____ before injection

• glucocorticoids

• phenothiazines

• Lithium

• Tricyclic antidepressants

• Phenytoin

• Thiazide diuretics

• Isoniazid

• Rifampin

• Ephedrine

The PET center personnel need to recognize that several commonly prescribed medications can elevate serum glucose levels, including:

Blood glucose levels

___________ can have a significant influence on tumor 18FFDG uptake because 18F-FDG and glucose compete for glucose transport and phosphorylation by hexokinase

decrease

Increased glucose levels _________ 18F-FDG uptake in the brain and in tumors because of direct competition between binding sites and enzymes

insulin

Increased _________ secondary to elevated blood glucose increases the translocation of GLUT4 (glucose transporter), thereby rapidly and efficiently shunting 18F-FDG to organs with a high density of insulin receptors (e.g., skeletal and cardiac muscles), resulting in altered radiotracer biodistribution and suboptimal image quality

150 and 200 mg/dL

The SNMMI recommends a pre-scanning glucose level of between

7 mmol/L (120 mg/dL)

The EANM suggests that an 18F-FDG study can be performed if the blood glucose level is less than

Benzodiazepines (oral, 0.5mg)

have been successfully used before PET imaging to relieve anxiety in claustrophobic patients, to relax skeletal muscles, and reduce BAT uptake.

fentanyl

Reduction of interfering 18F-FDG uptake in BAT with use of intravenous __________ premedication

Oral b-blocker propranolol

For patients with prominent brown adipose tissue uptake: ______________________, 20 mg, 1 hour before 18F-FDG injection 

3.5 mSv

The coefficient for effective dose from FDG in adults is 1.9×10−2 mSv/MBq according to ICRP publication 106, i.e. about _______ for an administered activity of 185 MBq

1 to 20 mSv

The effective CT dose ranges from _______ and may be even higher for a static high resolution diagnostic CT examination

4.7 mGy

The International Commission on Radiological Protection (ICRP) reports that for an adult patient the administration of 259 MBq (7 mCi) of FDG results in an absorbed radiation dose of _______ to the nongravid uterus (i.e. 1.8×10−2 mGy/MBq)

12 H

As the lactating breast accumulates FDG, it is suggested that contact between mother and child be limited for ____ after injection of FDG to reduce the radiation dose that the infant receives from external exposure to radiation emitted by the mother.

NOT

The ICRP does _____ recommend interruption of breastfeeding after FDG administration since little FDG is excreted in the milk.