This document discusses the concept of biological effective dose (BED) which is a radiobiological model used to predict clinical outcomes when radiation treatment parameters are altered. It defines BED and provides the formula. It also discusses α and β values, dose limiting organs for various radiopharmaceutical therapies, and safety measures and dose limits reported in literature to protect organs like the kidney, liver, lung, and bone marrow.
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Normal organ biological effective dose azmal su jamila
1. Normal organ Biological Effective Dose
(Saving kidney, bone marrow and liver)
Safety and toxicity
Azmal/Su/Jamila
2. BED: Introduction
• Radiobiological model
• Can help predict clinical outcomes when treatment
parameters are altered
• base on:
– linear quadratic model
– radiobiological data for patients
• assumes:
– full repair between two fractions
– no proliferation of tumor cells
3. BED: Definition
Biologically effective dose (of a given schedule) is:
• the total dose required to give the same log cell kill
as the schedule being studied,
• at an infinitely low dose-rate or with infinitely small
fractions well spaced out;
• with an overall time factor for repopulation during
continued irradiation
• for a tissue with a particular α/β ratio only
4. BED: Formula
BED=nd(1+d/[α/β]) - loge2 (T-Tk)/αTp
• n fractions of
• d Gy are given
• in an overall time of T days
• and tumour repopulation doesn’t start until day Tk
(using k for kick-off, or onset, of the delayed
repopulation during fractionated irradiation)
• assuming a constant repopulation rate or cell
doubling time Tp up to the end of the RT
5. α and β
• tissue specific coefficients for radiation damage
• α proportional to dose (one single event is lethal)
• β proportional to dose squared (two sublethal
events required for lethal damage)
• α/β ratio
- repair capacity
- quantifies the sensitivity of a given tissue to
changes in fractionation
6. Dose limiting organ
(organ with largest absorbed dose)
• nonmyeloablative radionuclide therapy: red marrow
• 90Y-ibritumomab tiuxetan therapy: liver
• 131I-tositumomab: lung, liver and kidney
• peptide receptor radionuclide therapy (PRRT): red
marrow and kidney
• 90Y-glass or resin microsphere: liver and lung
• 11C-docetaxel: liver and gall bladder
• 89Sr, 153Sm, 186/188Re- RP: bone surface, red marrow
• 223 RaCl2 : bone surface
7. Dose limiting organ
(organ with largest absorbed dose)
• nonmyeloablative radionuclide therapy: red marrow
• 90Y-ibritumomab tiuxetan therapy: liver
• 131I-tositumomab: lung, liver and kidney
• peptide receptor radionuclide therapy (PRRT): red
marrow and kidney
• 90Y-glass or resin microsphere: liver and lung
• 11C-docetaxel: liver and gall bladder
• 89Sr, 153Sm, 186/188Re- RP: bone surface, red marrow
• 223 RaCl2 : bone surface
12. Megalin
• 600 kD, member of LDL protein family
• Also known as LRP2
• A multiligand binding receptor
• Expressed in plasma membrane of absorptive
epithelial cells: lungs, oviducts, thyroid,
parathyroid, eyes & ears
• Present as Megalin/Cubilin complex, a
scavenging protein receptor in apical
membrane of renal proximal tubular cells.
13. Megalin
• Facilitates renal re absorption (endocytosis) of
peptides, (binding) proteins, hormones, drugs,
toxins and enzymes.
• Re absorption of radio-labeled octreotide in
mice.
• ↓uptake and ↓renal retention of 111In-SSTR
analogue is seen in absence of megalin.
14. Figure: Abdominal scintigraphy in a patient
after 220MBq 111DTPA-octreotide:
(A) without and (B) with coinfusion of LysArg
Renal activity 52% controlled with LysArg
A B
Eur J Nucl Med (2003) 30:9-15
15. Liver
Portal triaditis
Low gr pHTN
RE Induced Liver Disease
(REILD)
99mTc-MAA
3D voxel
Bremsstrahlung SPECT
90Y PET
SPECT/MR
35-520 Gy
Lobar/segmentalRE
Fractionation
16. Dose delivered to liver
Figure : Liver absorbed dose and tolerability Front Oncol 2014 4: 210
18. Dose delivered to lung
Figure : Lung absorbed dose and tolerability Front Oncol 2014 4: 210
19. Suggested normal limits from literature
RN Disease Max Limit
131I DTC, Benign thyroid, NB, BCL 2Gy to blood
90Y Liver NET 2Gy to BM
Radio
peptide
NET 28Gy and 40Gy for
kidneys
90Y-
microsp
heres
HCC, metastatic liver tumors Variable ?35-520Gy
Zevalin NHL, Follicular lymphoma WB AD 1.3-2.4mGy/MBq
Bexxar NHL. Folliclar lymphoma WB AD 0.65-0.75 Gy
20. Suggestedsafetymeasuresfromliterature
RN Organ safety measures
131I, 90Y Bone marrow Individual dose optimization
radio
peptide
Kidney Co administratin of amino acids
90Y-
microsp
heres
Liver Selective placement of catheter to
hepatic artery, targeting of least
possible number of segments
90Y-
microsp
heres
Lung LS 20%, <20 or 30Gy
21.
22. References
Fowler. Br J Radiol, 2010; 83:554-568
Jones et al. Clin Oncol, 2001;13:71-81
Brady et al. Cancer J 2013;19: 71-78
Cremonesi et al. J Nucl Med, 2007;48:1871-1879
Rajendran et al. J Nucl Med, 2008;49:837-844
van der Veldt et al. Eur J Nucl Med Mol Imaging, 2010;37:1950-1958
Rolleman et al. Eur J Nucl Med, 2003;30:9-15
Cremonesi et al. Front Oncol, 2014;4:210
Forreretal.Eur J Nucl Med Mol Imaging, 2009;36:1138-1146
Baroneetal. JNuclMed.2005;46:99s-106s
Bodeietal.EurJNuclMedMolImaging.2008;35:1847-1856
Otteetal.Eur J Nucl Med,1999;26: 1439-1447
Fisher et al. J Nucl Med, 2009;50:644-652
Zevalin prescribing information; http://www.zevalin.com/v3/pdf/
Bexxar prescribing information; http://us.gsk.com/products/assets/ us_bexxar.pdf.
O’Donoghue et al. Cancer Biother Radiopharm, 2002;17:435-443
Boucek et al. Eur J Nucl Med Mol Imaging, 2005;32:458-469
Notes de l'éditeur
Biology
Tp is a little shorter than Tpot (potential doubling time measured before the tumour has received any cytotoxic treatment)
Typical values for the α/β ratio : 5–25 Gy for early-reacting normal tissues and tumors and 2–5 Gy for late-responding normal tissues
Cremonesi et al. J. Nucl. Med. 2007; 48 (11)
Rajendran et al. J. Nucl. Med. 2008; 49: 837-844
van der Veldt et al. Eur J Nucl Med Mol Imaging (2010) 37:1950–1958
Slifstein et al. J. Nucl. Med. 2006; 47 (2) 11C-Raclopride striatal dopamine D2 receptor imaging: gall bladder
Dosimetry is beneficial because it predicts:
Probability of toxicity
Normal tissue complication probability (NTCP)
Tumor response
Tumor control probability
Forrer et al. Eur J Nucl Med Mol Imaging, 2009;36:1138-1146
Blood smear_MDS_hypogranular neutrophil_pseudo-Pelger-Huet nucleus_RBC: poikilocytosis(Wright-Giemsa stain)
Bone marrow aspirate smear_MDS_dyserythropoiesis_nuclear hypolobation (pseudo–Pelger-Huët nucleus) of granulocyte_blast cell
Same for different analogues
No temporal change in term of total renal uptake but cortico-medullary discrepency
Independent of sex and ?SSTR expression
Matches with variation expression density of megalin in renal cortex, medulla and parts of PCT
60%, 85% and 30% reduction is seen with co administration of D-lysin, sodium maleate and cisplatin
Megalin and cubilin mediated endocytosis; Somatostatin receptor mediated uptake; Fluid phase endocytosis (pinocytosis); Organic anion trasnporter mediated peritubular absorption
azotemia, HTN, severe anemia (months to years after irradiation), if untreated, (gradual ↓CCR) leads to renal failure.
mesangiolysis, sclerosis, tubular atrophy, and tubulointerstitial scarring
Grading of histologic renal damage was most pronounced in female WT mice. Damage was similar but less frequent in megalin deficient mice.
Rolleman et al. Eur J Nucl Med (2003) 30:9-15
REILD manifest within 2 mo of RE (unlike 2-24 wk of EBRT induced RILD, central vein injury)
Lobar or segmental RE can deliver higher AD compared to AD delivered to whole liver; lower volume of non tumoral liver parenchyma treated, higher is the tolerability.
Basal liver function; patient naïve to RE
Multiple administration with reduced parenchymal adsorbed dose result in lower BED, i.e. lower toxicity than a higher single dose administration
Z1 encircles the portal tracts (hepatic arteries) Z3 is around central veins. Z2 bwn
The graph shows the liver absorbed doses (Gy) reported in the literature with information about the associated liver tolerability. Red bars represent liver toxicity with fatal event (death); orange bars represent the threshold for observed toxicity or the limit recommended by the author; green bars represent tolerated absorbed doses. References are reported in parenthesis after the name of the first author. t., treatment; *(77) patient with previous EBRT (21 Gy) and RE with 71 Gy
The graph shows the lung absorbed doses (Gy) reported in the literature, with information about the associated lung tolerability. The absorbed doses taken from the literature are reported although these are derived without including the attenuation correction. Absorbed dose values should be rescaled by an average factor of 0.6 (12). Red bars represent radiation-induced pneumonitis leading to death; orange bars represent the threshold for observed radiation-induced pneumonitis or the limit recommended by the author; green bars represent tolerated absorbed doses. The references are reported in parenthesis after the name of the first author.
Forrer et al. Eur J Nucl Med Mol Imaging (2009) 36:1138–1146
Barone et al. J Nucl Med. 2005;46(suppl 1); Bodei et al. Eur J Nucl Med Mol Imaging. 2008;35; Otte et al. Eur J Nucl Med1999;26(11)
Front Oncol 2014 4: 210
Zevalin prescribing information [package insert]. Irvine, CA: Spectrum Pharmaceuticals, Inc.; 2009. Available at: http://www.zevalin.com/v3/pdf/
Zevalin_Package_Insert.pdf. Accessed October 25, 2010.
Fisher DR, Shen S, Meredith RF. MIRD dose estimate report no. 20: radiation absorbed-dose estimates for 111In- and 90Y-ibritumomab tiuxetan. J Nucl Med. 2009;50:644–652
Bexxar prescribing information [package insert]. Research Triangle Park, NC: GlaxoSmithKline; 2005. Available at: http://us.gsk.com/products/assets/ us_bexxar.pdf. Accessed October 25, 2010
O’Donoghue JA et al. Hematologic toxicity in radioimmunotherapy: dose-response relationships for I-131 labeled antibody therapy. Cancer Biother Radiopharm. 2002;17:435–443
Boucek JA et al. Validation of prospective whole-body bone marrow dosimetry by SPECT/CT multimodality imaging in 131I-anti-CD20 rituximab radioimmunotherapy of non-Hodgkin’s lymphoma. Eur J Nucl Med Mol Imaging. 2005;32:458–469