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1 Management of Radioactive in a Nuclear Department

A Medical Perspective

Dr. Jennie Cooke and Bioengineering Dept St. James’s Hospital 2 -99m – the (almost) ideal for diagnostics 3

• Produced from a Mo-99 generator

• Gamma emitter with energy 140keV

• Half-life of 6 hours

• Can be labelled to a wide range of pharmaceuticals

• Imaging is performed with a SPECT system (Single photon emission computed ) typically with CT (x-ray) attenuation correction.

• Short lived waste (typically < 48 hours storage)

• Workhorse isotope – relatively large volumes of waste Se-75 - tauroselcholic [75 selenium] acid 4

• Mimics bile acid for the diagnosis of bile acid malabsorption

• Half-life – 120 days

• Activity administered is very low - < 370kBq

• Outpatient protocol Ga-68 PET imaging – the new wave 5 • Produced from a Ge-68 generator

emitter - annihilation producing 2 x 511keV photons

• Half-life of 68 minutes

• Can be labelled to a range of ligands

• Imaging is performed with a PET system (Positron emission tomography) typically with CT (x-ray) attenuation correction.

• Short lived waste (typically < 12 hours storage)

• Synthesis of peptides produces a large volume of waste. Some with Ge-68 (half life 271 days) is unavoidable. 6

Radiopharmaceutical Preparation

Patient administration

Uptake time & inpatients A Simple Preparation 7

 Operator dresses in PPE – disposable gown and gloves.

 Operator prepares a drip tray in the laminar flow cabinet lined with a low lint wipe to absorb spills.

 Technetium - 99m (Tc-99m) is eluted from the generator into a vial.

 A glass vial of radiopharmaceutical is swabbed with an alcohol wipe. Spills of Tc-99m are also absorbed using these.

 The required volume of Tc-99m is drawn from the eluate vial using a syringe and needle.

 The Tc-99m is diluted with saline from a 10ml plastic vial of NaCl. A Simple Radiopharmaceutical Preparation 8

 Operator dresses in PPE – disposable gown and gloves.

 Operator prepares a drip tray in the laminar flow cabinet lined with a low lint wipe to absorb spills.

 Technetium - 99m (Tc-99m) is eluted from the generator into a glass vial.

 A glass vial of radiopharmaceutical is swabbed with an alcohol wipe. Spills of Tc-99m are also absorbed using these.

 The required volume of Tc-99m is drawn from the eluate vial using a syringe and needle.

 The Tc-99m is diluted with saline from a 10ml plastic vial of NaCl. More complex operations… 9

 In vitro red blood labelling with Tc-99m

 In vitro labelling with In-111

 Blood handling for glomerular filtration rate measurements

 Complex labelling processes such as synthesis using larger disposables such as cassettes. More complex operations… 10

 In vitro labelling with Tc-99m

 In vitro white blood cell labelling with In-111

 Blood handling for glomerular filtration rate measurements

 Complex labelling processes such as synthesis using larger disposables such as cassettes. 11 RadiopharmacyRadiopharmacy Waste Waste Segregation Segregation

Tc-99m Tc-99m Long-lived Long lived Non- Sharps: non- isotopes radioactive sharps: sharps: non- Needles Gloves Synthesis cassettes Glass vials Gowns Wipes Synthesis waste vials Tray liner Radiopharmaceutical Administration 12

Intravenous: Capsule: Ventilation Study: Cannula Cup Vapourisation set PPE Gloves Absorbent sheets 13 InjectionRadiopharmacy Room Waste Waste Segregation Segregation

All other waste returned to Tc-99m Sharps: Tc-99m non- sharps: radiopharmacy for Needles Gloves disposal Cannulas Gowns Wipes Absorbent sheets Waste production during uptake time and from inpatients 14 Diagnostic Radiopharmaceutical Challenges 15

1. Segregation failures – larger volumes of long lived waste.

2. Long-lived contaminants: I-123 preparation which should have a half-life of 13.2 hours contains longer lived isotopes in small quantities: I-125 with a half-life of 60 hours and Te-121 (20 days).

Rather than expected max. storage of 160 hrs – we find we are storing large numbers of vials for >6 months. Radioiodine for cancer 16  The original targeted radiotherapy – is only absorbed by thyroid tissue.

 Patients first have total thyroidectomy.

 Iodine-131 is both a beta and high energy (364keV) gamma emitter (therapy and diagnostic imaging possible).

I-131 has a half-life of 8 days.  Gamma photons can be detected by sometimes producing the I-131 is administered in capsule form. characteristic star artifact.

 Beta particles are absorbed by and ablate any residual cells. Radioiodine therapy for thyroid cancer 17

• I-131 ablation patients are inpatients

• There are no and patients must be self-caring.

• Specially designed lined isolation suite, which is a controlled area when a treated patient is resident.

• Excretion is predominantly urinary

• All bodily fluids are contaminated during the first few days. Radioiodine therapy – sources of waste 18 Radioiodine therapy – sources of waste 19

In-sink In room washing Sharps macerator machine Radioiodine therapy – waste storage 20

• Large volumes of waste

• Often contaminated with decaying food (risk of pests)

• Stored for up to six months Radioiodine therapy – special waste challenges 21

• Patient with non-emptying colostomy bag

• Storage required for six months

• Concerns re odours and patient privacy

• Solution was to source a metal drum with airtight seal storage 22

 Waste is tagged, labelled with trefoil, isotope type and date.

 Transferred to short term waste store which is restricted by swipe access and locked out of hours.

 Longer lived isotopes store in long-term waste store where available (fire proof, alarmed).

 Remnants of vial containing prepared radiopharmacuticals (I-123, In- 111) and unused capsules (Se-75, I-131) stored in a locked safe inside waste store.

 All waste is stored until decayed to background levels (typically 6-12 half-lives). This is measured using a contamination monitor (scintillation where available, this varies from site to site). Final disposal 23

• Waste item measured using contamination monitor.

• If no measurement above background detected item can be disposed.

• Tags and trefoils are removed.

• Item is removed from waste register.

• All waste items tagged with cable tie with identifying number.

• Moved to general point.