Ped NM

Question 1

PET

Answer 1

Radiation burden reduce 50%
2.5 MBq/kg
0.2 mg/kg fusid to increase urine extraction

Question 2

CT

Answer 2

Dose length product converted into effective dose values
Pitch >1
Slice increment = slice thickness, no overlap
Activate dose modulation system

Question 3

SPECT/CT

Answer 3

Reduce scan length
Can rule out malignant bone lesions
Evaluate soft tissue involvement

Question 4

Bone scan radiation dose

Answer 4

<3 mSv

Question 5

F-fluoride PET

Answer 5

Better spatial resolution
Shorter duration of study (max 90 min)

Question 6

Condylar hyperplasia

Answer 6

Asymmetric growth of mandibular condylar metaphysis
Time for surgery at the end of developing age growth, before arising of degenerative alteration
Bone scan reveal when metabolic activity of metaphysis is declining compared to reference bone

Question 7

Dynamic renal scan

Answer 7

Tc-MAG3 and Tc-EC
Greater renal extraction - - better visualisation
15-20s/frame for 30-45 min posterior
Static after upright position

Question 8

Congenital Hydronephrosis

Answer 8

Self-limiting condition without obstruction
Kidney damage - - pyeloureteroplasty

Question 9

Static renal scan

Answer 9

Pinhole collimator
Postinfection scar - cold defect, triangular
At least 6 months after UTI
Negative scan - - absent or very low reflux - - no need for MCUG
Confirm/Exclude acute pyelonephritis

Question 10

Cystography

Answer 10

Intravesical administration of Tc
Most sensitive for VUR
Recurrent UTI - - detect and quantify VUR
MCUG is better for first evaluation
#6 French no balloon catheter warm saline mixed with Tc-pert or Tc-SC 15-30 MBq - - bladder max capacity - - remove catheter - - void
Follow up VUR or first exam when bladder dysfunction and urethral anomalies excluded

Question 11

Cystography protocol

Answer 11

10s/frame filling phase
2-5s/frame voiding phase
Tracer in ureter and renal pelvis - - VUR

Question 12

Thyroid

Answer 12

Tc-pert or I123-iodide
I131-high radiation burden
Uptake 0.4 MBq
4-6-24-96 h

Question 13

Thyroid cancer

Answer 13

Secondary after radiotherapy of HL, neuroblastoma - DTC
Primary cancer infiltrates capsule more often than adult - - T3
I131 cumulative activity <18.5 GBq to avoid sialoadenitis
After surgery – radioiodide ablation

Question 14

Neuroblastoma

Answer 14

Most common extracranial solid tumor of childhood
Adrenal or retroperitoneum
Diagnosed after 1 year - - advanced disease and worse prognosis

Question 15

I123-MIBG

Answer 15

Diagnostic
Better image quality and lower radiation
159 keV, no beta
T1/2 13h

Question 16

I131-MIBG

Answer 16

Target therapy
364 keV, beta
T1/2 8 days
Theragnostic

Question 17

MIBG protocol

Answer 17

Image 24h after IV
Medium energy parallel hole collimator
Reduce septal penetration by 3% photons with high energy photons 400 keV
Prevent blurring
Ant/post WBS, lateral skull, high count spot in abdomen

Question 18

SIOPEN

Answer 18

Standardized scoring system
Evaluate MIBG uptake
Extension of skeletal disease

Question 19

Negative MIBG

Answer 19

FDG - - uptake in Waldeyers ring, diffuse thymic uptake, brown fat tissue
FDOPA - higher accuracy and sensitivity than MIBG

Question 20

FDG indication

Answer 20

Hodgkins lymphoma
Ewing sarcoma
Soft tissue sarcoma
Osteosarcoma

Question 21

I131-MIBG therapy indication

Answer 21

Inoperable pheo, Paraganglioma, Carcinoid
Stage III or IV neuroblastoma
Metastatic or recurrent MTC
Reserved for patients with uptake

Question 22

I131 - MIBG therapy dose

Answer 22

100-300 mCi

Question 23

Lung scan

Answer 23

Tc-MAA or Tc-microspheres
Reduce injected activity and number of particles
Further reduce if right-to-left shunt
Tc-MAA - - reduce to 10000 particles - - reduce risk of systemic embolism

Question 24

Bronchopulmonary infection

Answer 24

Patchy distribution
Difficult interpretation
Postpone scan if wheezing
Slow injection in peripheral vein
Central line - - hot spot artifact

Question 25

Cavo-pulmonary anastomosis

Answer 25

Split the dose Inject multiple sites (upper and lower limbs)

Question 26

Infant

Answer 26

Avoid anterior view lung

Question 27

Evaluate shunt

Answer 27

Compare total lung counts with counts from ROI of whole brain Brain activity should be <1% of lung activity

Question 28

Main pulmonary trunk stenosis

Answer 28

Scan not sensitive Combi with echo Detailed evaluation of central pulmonary bed

Question 29

Congenital heart disease

Answer 29

Diffuse hypoperfusion Possible to observe focal perfusion defects - - most frequent cause - peripheral vascular abnormality or surgery (Blalock-Taussig shunt)

Question 30

Cardio scan

Answer 30

Tc-Sestamibi or Tc-tetrofosmin Sedation in children <6 y - - fasting Adenosine 0.14 mg/kg High resolution collimator with zoom Indication - anomaly of coronary arteries ALCAPA - anomalous origin of left coronary artery from pulmonary artery Post-op follow up

Question 31

Meckel

Answer 31

Fast 4-6h Premedication with gastric secretion inhibitor 12-24h before - - reduce release from gastric mucosa Dynamic anterior 128*128 1min/frame 60 min Focal spot of uptake simultaneously with stomach Up to 40-50 min in children Additional view to avoid urinary activity

Question 32

GER

Answer 32

Common in infants (incomplete maturation of lower sphincter) Disappear at 18-24 m Complications - regurgitation, vomit, dysphagia, wheezing, recurrent pneumonia

Question 33

Milk scan

Answer 33

Detect GER Fast 4-6 h Study when normal feeding time No sedation (alter motility) Regular volume of milk Insufficient volume - - decrease sensitivity for reflux and gastric emptying

Question 34

Milk scan protocol

Answer 34

1/3 contain tracer 2/3 to wash down activity Meal should not last >10-15 min - - avoid spillage - - absorbent sheets on lung Tc-SC 0.5 mCi in children <5y Can withstand low pH (also DTPA)

Question 35

Milk scan image

Answer 35

Dynamic 30s/frame over 60 min posterior mouth and upper abdomen + zoom Fast dynamic study after first swallowing act with child sitting - - 2-3 frames/s for 1 min - - esophageal transit Late image 2-4h - - gastric emptying and pulmonary aspiration 24h - - pulmonary aspiration during sleep Cine loop - - activity in esophagus - - GER - - report number of episodes, level and duration

Question 36

Gastric emptying in older children

Answer 36

Tc-SC added to egg Fast 4-6h Meal <10 min. 30s/frame for 60 min 2-3-4h

Question 37

Salivagram

Answer 37

Aspiration of saliva Single drop 0.1 ml Tc-SC or DTPA 10 MBq under tongue Dynamic posterior 128*128 10-30 s/frame 60 min Oropharynx and thorax Static with marker on xiphoid, supra sternal notch, axillae Cine loop Appear in trachea/bronchi - - note the level Distal aspiration more relevant

Question 38

Child abuse finding on bone scan

Answer 38

Scapula fracture

Question 39

Shin splints

Answer 39

Posteromedial cortex

Question 40

Lower back pain in young adults

Answer 40

Spondylolysis Repetitive trauma - - disruption of pars interarticularis L5

Question 41

Hyperthyroidism

Answer 41

Graves 6-12 m antithyroid drugs More radical approach for: severe side effects, non responders, relapse More common in children

Question 42

Ectopic thyroid

Answer 42

Lifelong hypothyroidism Higher dose of L-thyroxine