Current Australian diagnostic reference levels for nuclear medicine

 

 

 

Nuclear medicine diagnostic reference levels

 

The DRLs are not recommended doses. They are only a reflection of current practice within Australia. The DRLs should not be used as the basis of calculating paediatric doses or as a starting point for facilities conducting a scan for the first time. Most importantly, if your facility uses a dose lower than the DRL, you should not increase the dose you use to match the DRL.

While it is true that the median dose is also not a recommendation, ARPANSA believes that the median dose is a reasonable starting point for facilities to use when introducing procedures they haven’t performed before. As with the DRL, if your facility uses a dose lower than the median dose, you should not increase your doses to match.

If the activity your facility routinely administers is higher than the DRL then you should review your protocols. When doing so, ensure that any reduction in dose does not degrade the image quality to the point where diagnosis is compromised. Maintaining diagnostic quality is of paramount importance, even if doing so requires a dose higher than the DRL (which might occur if your facility uses older hardware or regularly images patients with clinical indications that are underrepresented within the NDRLS data).

The tables below provide links to images (gif format) showing the data used to derive the DRL. Contact us if an alternate format is required.

General nuclear medicine

The 25th percentile, median and DRL doses are expressed in term of MBq, unless otherwise stated.

Category - cardiac

Procedure name	Nuclide	Chemical form	Route of admin.	25th percentile	Median	DRL
Cardiac first pass	Tc-99m	Pertechnetate, Red cells	IV	590	875	930
Cardiac L/R shunt	Tc-99m	Pertechnetate	IV bolus	400	550	900
Cardiac R/L shunt	Tc-99m	MAA	IV	100	150	185
Gated blood pool scan	Tc-99m	Red cells	IV	900	990	1030
Myocardial hot spot	Tc-99m	PYP	IV	720	800	800
MPI - Rest	Tl-201	Chloride	IV	80	115	120
MPI - Stress	Tl-201	Chloride	IV	100	120	120
MPI - Reinjection	Tl-201	Chloride	IV	30	40	40
MPI - Single phase	Tc-99m	Tetrofosmin, MIBI	IV	350	475	620
MPI - 1 day rest + stress	Tc-99m	Tetrofosmin, MIBI	IV	1250	1400	1520
			Note: dose is for both studies combined
MPI - 1 day rest (201Tl) /stress (99mTc)	Tl-201	Chloride	IV	100	110	130
	Tc-99m	Tetrofosmin, MIBI	IV	900	1000	1050

Category - endocrine

Procedure name	Nuclide	Chemical form	Route of admin.	25th percentile	Median	DRL
Parathyroid	Tc-99m	Tetrofosmin, MIBI	IV	765	820	900
Parathyroid subtraction	Tc-99m	Pertechnetate	IV	45	75	220
Thyroid	I-123	Iodide	IV	180	185	345
Thyroid	Tc-99m	Pertechnetate	IV	200	210	215

Category - gastrointestinal

Procedure name	Nuclide	Chemical form	Route of admin.	25th percentile	Median	DRL
Blood loss	Tc-99m	Red cells	IV	800	1000	1000
Colonic transit	Ga-67	Citrate	Oral	6	10	20
Gastric emptying	Ga-67	Citrate	Oral	10	15	20
Gastric emptying	Tc-99m	Colloid, DTPA	Oral	39	43	44
Oesophageal reflux	Tc-99m	Colloid, DPTA	Oral	40	40	40
Oesophageal transit	Tc-99m	Colloid, DPTA	Oral	20	40	40
Small bowel transit	Tc-99m	Colloid, DPTA	Oral	20	40	40
Meckel’s diverticulum	Tc-99m	Pertechnetate	IV	225	400	400
Salivary glands	Tc-99m	Pertechnetate	IV	150	185	200

Category - genitourinary

Procedure name	Nuclide	Chemical form	Route of admin.	25th percentile	Median	DRL
Renal cystogram	Tc-99m	Pertechnetate	Bladder	40	50	94
Renal scan	Tc-99m	DMSA	IV	120	150	200
Renal scan	Tc-99m	DTPA	IV	380	400	500
Renal scan	Tc-99m	MAG3	IV	235	270	305
Renal transplant	Tc-99m	DTPA, MAG3	IV	200	300	400
Testicular scan	Tc-99m	Pertechnetate	IV	210	400	600

Category - haematological

Procedure name	Nuclide	Chemical form	Route of admin.	25th percentile	Median	DRL
Arterial infusion	Tc-99m	MAA	Intra- arterial	100	135	190
Le Veen shunt	Tc-99m	Colloid	Intra- peritoneal	95	185	200
Venogram	Tc-99m	Pertechnetate	IV	700	770	800
Hepatobiliary	Tc-99m	HIDA, DISIDA, DIDA	IV	185	205	210
Liver blood flow	Tc-99m	Red cells	IV	800	900	1000
Liver/spleen	Tc-99m	Colloid	IV	150	200	200
Liver transplant	Tc-99m	HIDA, DISIDA	IV	155	185	200

Category - infection

Procedure name	Nuclide	Chemical form	Route of admin.	25th percentile	Median	DRL
Infection	Ga-67	Citrate	IV	185	200	220
Infection	Tc-99m	WBC-colloid, WBC-HMPAO	IV	500	700	800

Category - lacrimal

Procedure name	Nuclide	Chemical form	Route of admin.	25th percentile	Median	DRL
Lacrimal drainage	Tc-99m	Pertechnetate	Eye drops	7	10	18
			Note: dose is expressed in terms of drops per eye

Category - lymphatic

Procedure name	Nuclide	Chemical form	Route of admin.	25th percentile	Median	DRL
Lymphoscintigraphy	Tc-99m	Nanocolloid	Perilesional	33	42	52
			Note: dose is for entire procedure, not per injection

Category - nervous system

Procedure name	Nuclide	Chemical form	Route of admin.	25th percentile	Median	DRL
Brain	Tc-99m	DTPA	IV	800	800	900
Brain	Tc-99m	HMPAO, ECD	IV	640	720	750
CSF leak	In-111	DTPA	Intrathecal	15	21.5	38
CSF leak	Tc-99m	DTPA	Intrathecal	77	300	370
CSF shunt patency	Tc-99m	Pertechnetate, DTPA	Cisternal	40	40	80

Category - oncology

Procedure name	Nuclide	Chemical form	Route of admin.	25th percentile	Median	DRL
Somatostatin receptors	In-111	Octreotide	IV	200	200	240
Thyroid - wb scan for Ca	I-123	Iodide	Oral	190	310	400
Thyroid - wb scan for Ca	I-131	Iodide	Oral	100	150	185
Tumour	Ga-67	Citrate	IV	300	400	400
Tumour	I-123	MIBG	IV infusion	200	290	400
Tumour	I-131	MIBG	IV infusion	24	31	38
Tumour	Tc-99m	MIBI	IV	740	800	800
Tumour	Tc-99m	[V]-DMSA	IV	370	400	440
Tumour	Tl-201	Chloride	IV	115	125	185

Category - pulmonary

Procedure name	Nuclide	Chemical form	Route of admin.	25th percentile	Median	DRL
Lung perfusion	Tc-99m	MAA	IV	200	220	240

Category - skeletal

Procedure name	Nuclide	Chemical form	Route of admin.	25th percentile	Median	DRL
Bone marrow	Tc-99m	Colloid, nanocolloid	IV	250	400	550
Bone scan	Tc-99m	MDP, HDP	IV	810	840	920

Category - splenic

Procedure name	Nuclide	Chemical form	Route of admin.	25th percentile	Median	DRL
Liver/spleen - see Hepatobiliary
Spleen	Tc-99m	Denatured RBCs	IV	200	335	705

Category - non-imaging

Procedure name	Nuclide	Chemical form	Route of admin.	25th percentile	Median	DRL
Breath test	C-14	Urea	Oral	0.037	0.037	0.037
GIT blood loss	Cr-51	Red cells	IV	4	4	5.5
Plasma volume	I-125	HSA	IV	0.2	0.25	0.5
Red cell survival	Cr-51	Red cells	IV	4	6	7
Red cell volume	Cr-51	Red cells	IV	1	2	4
Renal GFR	Tc-99m	DTPA	IV	60	80	100
Renal GFR	Cr-51	EDTA	IV	3	4	4

NM CT

The DRLs below are for CT scans conducted for the purposes of attenuation correction or localisation in conjunction with a SPECT scan. There were numerous submissions for skeletal CTs conducted of the extremities, but no DRL has been issued because the effective dose of such scans is minimal.

If your facility regularly delivers a dose higher than the DRL, you may be using a larger scan region than required for the clinical task or you might be conducting a higher quality scan than required.

Category	Region	25th percentile (mGy.cm)	Median (mGy.cm)	DRL (mGy.cm)
Cardiac	Chest	25	40	45
Lymphatic (Breast Ca.)	Chest	80	115	170
Neurological	Brain	45	225	255
Parathyroid	Neck/Chest	140	205	255
Pulmonary	Chest	70	95	120
Skeletal	Axial	115	170	240
	Axial (2 bed)	195	340	415

PET

FDG scanning in PET is one of the few nuclear medicine procedures where weight correction is used routinely at the majority of Australian imaging facilities. However, there were a number of the submissions to the NDRL survey from facilities that clearly didn’t conduct weight correction. As a result, two DRLs for whole body FDG scans have been issued.

Category	Pharmaceutical	25th percentile (MBq)	Median (MBq)	DRL (MBq)
Body	F-18 FDG	225	250	310
Body (weight corrected)	F-18 FDG	2.5 x kg + 75	2.5 x kg + 100	2.5 x kg + 125
Brain	F-18 FDG	200	220	250

There were submissions from facilities using Ga-68 dotatate and PSMA, however, the liaison panel suggested that the amount of activity used in Ga-68 scans is largely independent of the pharmaceutical used and the clinical indications of the patient and that issuing a DRL would be inappropriate. For information purposes only, the Ga-68 percentiles are shown below.

Category	Pharmaceutical	25th percentile (MBq)	Median (MBq)	75th percentile (MBq)
Ga-68	Dotatate/PSMA	150	150	190

PET CT

The DRLs below are for CT scans conducted for the purposes of attenuation correction or localisation in conjunction with a PET scan.

Region	25th percentile (mGy.cm)	50th percentile (mGy.cm)	DRL (mGy.cm)
Head/Brain	75	125	325
Whole body (Eyes - Thighs)	325	430	540
Whole body (Vertex - Toes)	495	655	985

 

Further information on International Best Practice for Radiation Protection of Patients can be found on the International Atomic Energy Agency Radiation Protection of Patients website, which can be accessed via the following link:

IAEA Radiation Protection of Patients (RPOP)