NMT Boards – Scheduling, Supply & Exam Setup

Bone scan delay between injection and imaging

2–4 hours

Actual camera time for a whole-body bone scan

About 60 minutes

Extra camera time when SPECT/CT is added to a bone scan

20–30 minutes

Thyroid uptake measurement times

4–6 hours and 24 hours

HIDA dynamic acquisition length

60 minutes starting at injection

Standard FDG PET uptake time

About 60 minutes

FDG PET scan time itself

About 15–30 minutes

Gastric emptying (solid) imaging times

0, 1, 2 and 4 hours

Ga-67 imaging delay

24–72 hours

In-111 WBC imaging times

About 4 h and/or 18–24 h

Bone scan injected 8:00, imaged 11:00 for 60 min. When is the camera free?

Until 11:00 and after 12:00

Same-day cardiac MPI total visit length

About 3–4 hours

Why long QC acquisitions (SPECT maps, PET normalization) are run overnight

They need very high counts

Is gamma camera QC frequency set by the NRC?

No, manufacturer and accreditation standards

Downscatter direction

Higher energy into lower energy window

General rule for sequencing two isotopes in one patient

Lower-energy or shorter-lived study first

Where long-lived tracers (Ga-67, In-111, I-131, Tl-201) go in the sequence

Last

Order for Xe-133 ventilation and Tc-99m MAA perfusion

Xe-133 first, then MAA

Why Xe-133 ventilation precedes Tc-99m MAA

Tc-99m 140 keV downscatters into 81 keV window

Tc-99m DTPA aerosol then MAA perfusion: perfusion activity relative to ventilation

About 3–4× the ventilation counts

Order for thyroid radioiodine uptake and Tc-99m pertechnetate scan

Radioiodine uptake first

Dual-isotope parathyroid: which isotope is given first

I-123

Dual-isotope parathyroid windows

159 keV (I-123) and 140 keV (Tc-99m)

How dual-isotope parathyroid isolates the adenoma

Subtract I-123 image from Tc-99m sestamibi image

Single-isotope alternative for parathyroid imaging

Tc-99m sestamibi dual-phase

Order for bone scan and Ga-67 for osteomyelitis

Bone scan first

Order for NM abdominal study and barium study

NM first

Why barium spoils NM abdominal images

Attenuates photons, causing cold artifacts

Atomic number of barium

56

Atomic number of iodine

53

Sequencing mnemonic

Low before high, short before long, iodine before contrast, NM before barium

Wait after iodinated contrast before I-131 imaging or therapy (SNMMI/EANM)

4–6 weeks

Does non-contrast CT for attenuation correction affect radioiodine studies?

No

Are Tc-99m or F-18 studies affected by iodinated contrast?

No

Thyroid cancer patient had contrast CT 10 days ago. I-131 therapy today?

No, wait 4–6 weeks

Negative contrast agents

Air, O₂, CO₂ (appear dark)

Positive contrast agents

Barium sulfate and iodine (appear bright)

Barium contraindication

Possible bowel perforation

Contrast used instead of barium when perforation is possible

Water-soluble iodinated oral contrast (Gastrografin)

Ionic contrast particle ratio

3:2

Non-ionic contrast particle ratio

3:1

Osmolality of ionic (HOCM) contrast

1,300–1,600 mOsm/kg

Osmolality of non-ionic (LOCM) contrast

500–850 mOsm/kg

Osmolality of blood plasma

285–290 mOsm/kg

Effect of warming contrast

Lowers viscosity

Pediatric IV contrast dose for CT abdomen

2.0 mL/kg, max 150 mL

Percentage of patients who react to contrast

6–8%

Percentage of severe contrast reactions

Less than 1%

Epinephrine the technologist prepares for anaphylaxis

1 mL of 1:1,000 subcutaneous

How often the crash cart is checked

Daily

Metformin hold around iodinated contrast (Bolus)

48 h before and 48 h after

Risk of metformin with iodinated contrast

Lactic acidosis

Contrast-related risk with beta-blockers

Higher anaphylaxis risk

Contrast premedication drugs

Steroids and diphenhydramine

Mnemonic for ionic vs non-ionic contrast

Ionic splits (3:2), non-ionic sits (3:1)

License element setting max activity on hand

Possession limit

Is authorized user status general or per use category?

Per use category

Training hours for AU under 10 CFR 35.290 imaging

700 hours

Regulation for license amendments

10 CFR 35.13

When a license amendment must be approved

Before the new use begins

Agency regulating the Mo-99 breakthrough limit

NRC (or Agreement State)

Agency regulating drugs, kits and investigational agents

FDA

Agency regulating transport and packaging

DOT

Agency setting purity standards (Al³⁺ limit, radiochemical purity)

USP

Agency regulating worker safety

OSHA

Time to which unit doses are calibrated

Scheduled administration (injection) time

Half-life of Ga-68

About 68 minutes

Half-life of F-18

About 110 minutes

Half-life of Rb-82

75 seconds

Half-life of Mo-99

66 hours

Half-life of Tc-99m

6 hours

Half-life of Ge-68

271 days

Half-life of Sr-82

25 days

How adjunct drugs like sincalide are stocked

Par levels (not decay-driven)

Generator column material in Mo/Tc generator

Alumina (Al₂O₃)

Chemical form of Tc-99m eluted from the generator

Sodium pertechnetate

Eluent for the Mo/Tc generator

Saline

Wet column generator: eluate volume set by

Collection vial size

Dry column generator: eluate volume set by

Volume of saline used

Source of Mo-99 in commercial generators

Fission of U-235

Advantage of fission Mo-99

High specific activity

Sterilizing filter in the generator

0.22-µm membrane filter

Generator elution efficiency

85–95%

Causes of low generator yield

Air leak, channeling, reduced Tc

Generator records after every elution

Total activity, time of assay, volume

Time to maximum Tc-99m regrowth after elution

About 24 hours

Tc-99m on column 24 h after elution

About 87% of Mo-99 activity

Tc-99m on column 6 h after elution

About 44%

Equilibrium type of Mo-99/Tc-99m

Transient

Equilibrium type of Sr-82/Rb-82 and Ge-68/Ga-68

Secular

Transient equilibrium: parent half-life relative to daughter

About 10× longer

Secular equilibrium: parent half-life relative to daughter

More than 100× longer

In transient equilibrium, daughter activity compared with parent

Slightly more than parent

In secular equilibrium, daughter activity compared with parent

Equals parent

No equilibrium occurs when

Daughter half-life longer than parent

Equilibrium mnemonic

Tc is Transient; Sr/Rb is Secular

Rb-82 generator: first daily elution volume discarded

50 mL

Rb-82 generator: minimum wait between elutions

10 minutes

Time Rb-82 QC sample stands before Sr assay

At least 1 hour

Sr-82 breakthrough limit

0.02 µCi per mCi Rb-82