NEUTRON THERAPY PLANNING

Transcription

1 NEUTRON THERAPY PLANNING University of Washington Seattle, WA Patricia Sponseller, MS, CMD, RTT (R)(T) 1

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5 Alex Levine Photography 5

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7 THANK YOU! Rob Emery, MS Ruedi Risler, PhD Donna Kubik, MS Tom Arbuckle, CMD Evan Chapman, CMD Tammy Korssjoen, CMD Dr. Jason Rockhill, PhD Dr. George Laramore, PhD Alan Kalet, MS Ira Kalet, PhD Jon Jacki, PhD 7

8 OBJECTIVES History CNTS Facility at UWMC Patient population Treatment planning system Case study Future developments 8

9 HISTORY 1932 Fundamental discovery Proved existence of neutrons 1935 Nobel Peace Prize Treat cancer Sir James Chadwick 9

10 CLINICAL USE 1938 Robert Stone treated 240 patients Significant radiation effects Interest dropped off for next 20 yrs Records reviewed Inappropriate RBE value Rockhill J, Laramore G 10

11 1970 S Hammersmith Hospital, London Mary Catterall Head and neck patients-favorable results Increased interest world-wide Rockhill J & Laramore G 11

12 1979 FUNDING 12

13 $$$ In 1979 $8.5 million Translates to $27.5 million 2013 Self-sustaining after first 5 years Hardware very robust, year lifespan Use profile as a clinical facility and physics facility October st patient treatment 13

14 CYCLOTRON Clinical Neutron Therapy System (CNTS) at University of Washington is a computer controlled cyclotron and neutron therapy treatment unit Located at UWMC 14

15 CONTRACTORS Scanditronix (Uppsala, Sweden) Elven (Crawley, England) 15

16 Fast neutrons for cancer treatments Proton and other charged particles for medical radionuclide production Particles for medical physics and radiobiology experiments Materials testing for commercial vendors UWMC CNTS 16

17 CYCLOTRON Short metallic cylinder, divided into 2 sections, dees Deuterons accelerated to (15-50 MeV) bombarded into a Be target Kahn, F 17

18 CNTS FACILITY 18

19 3 BEAMLINES 19

20 CYCLOTRON 150 cm SAD d-max cm Target: Beryllium ½ of proton energy creates fast neutrons, other is deposited in Cu backing 50 MeV neutrons, Ave energy 22 MeV Wedges or filters, oriented in 4 cardinal positions 20

21 Housing and treatment couch 21

22 Gantry rotation, floor retracts 22

23 Gantry 23

24 MLC LEAVES 24

25 MULTILEAF COLLIMATION 25

26 Equipped with kilovoltage imaging 26

27 Kilovoltage Imaging 27

28 DOSE DISTRIBUTION Neutrons Photons 28

29 LINEAR ENERGY TRANSFER Low LET: few events per length (protons and photons) High LET: densely spaced events (neutrons) Risler R, Laramore G 29

30 RELATIVE BIOLOGICAL EFFECTIVENESS Measure of capacity for specific radiation to produce a specific biological effect Type of radiation is assigned a number to compare the effective doses Laramore G. et al., Cox J and Ang K. 30

31 WANT TO KNOW MORE? Information about operation and development of the facility Links to papers, reports and textbooks 31

32 UWMC EXPERIENCE Treated all sites Good results in some head and neck tumors, particularly salivary tumors Apparent neutron treatment limited use Rockhill J & Laramore G 32

33 ADENOID CYSTIC CARCINOMAS OF THE SALIVARY GLANDS Pubs.niaaa.nih.gov 33

34 MID-1980 S CLINICAL TRIAL Only randomized trial for salivary tumors with neutrons RTOG/MRG (Scotland) trial 1980 s Compare neutrons vs photons High risk or bulky tumors Study stopped early for ethical reasons 34

35 PROBABILITY OF CONTROL/TYPE OF TREATMENT Neutrons better local control 56% neutron vs 17% photon group Salivary tumors particularly adenoid cystic most benefit Laramore G et al. 35

36 NEUTRON RT SALIVARY GLAND 36

37 OTHER SITES CURRENTLY TREATED Recurrent sarcomas Adenoid cystic trachea carcinomas Locally advanced melanomas 37

38 CUSTOMIZED DENTAL STENT 38

39 CT SIMULATION 39

40 TREATMENT PLANNING Until Spring 2011, planning completed on in house system, PRISM (Developed 1988 by Ira Kalet & others) Outdated system Dosimetry had many work arounds 40

41 CURRENT NEUTRON PLANNING Neutron beam modeled in Philips Pinnacle using a combination of photon beams Alan M. Kalet, George A. Sandison, Mark H. Phillips, Upendra Parvathaneni, Validation of the Pinnacle3 photon convolutionsuperposition algorithm applied to fast neutron beams, J Appl Clin Med Phys Yet, some work arounds 41

42 PRESCRIPTION 1920 NcGy over 16 fractions (120 NcGy/fx) Adopted from Hammersmith Hospital (England) experience 4 days a week treatment Machine maintenance At UWMC new beam data acquired 2005 RX 1840 NcGy/16 fxs (115 NcGy/fx) 42

43 TREATMENT PLANNING CONSIDERATIONS Clipart.com 43

44 4 set of leaves 1.25 cm 2 center leaves 1.4 cm Outer 5 sets of leaves 2.0 cm (3 shown) 44

45 DOUBLE FOCUSING LEAVES 45

46 HALF BEAM BLOCKING 46

47 Cyclotron is equipped with wedges or filters WEDGES OR FILTERS 47

48 NORMAL TISSUE TOLERANCES All tissue irradiated is damaged, no repair RBE is not same for all structures Dose tolerances must be respected! PTV s near base of skull structures are usually under-dosed 48

49 Optic nerves, optic chiasm, spinal cord, 1150 NcGy Temporal lobe NcGy Cerebellum NcGy Globe of eye NcGy Brainstem approx 1150 NcGy 49

50 Plan entire course up front Large scatter component to beam Internal scatter Block critical structures before tolerance May need to move isocenter for boost plan(s) 50

51 CASE STUDY 47 yr old female with adenoid cystic carcinoma, mass in cavernous sinus invading Mekel s cave and infratemporal fossa Custom dental stent Rx to 1840 NcGy Critical structures: RT/Lt optic nerves, optic chiasm, brainstem, spinal cord, RT/LT lacrimal glands, RT/LT globes, RT/Lt temporal lobes 51

52 RED PHYSICIAN PTV 1840 NCGY 52

53 INITIAL CONFORMAL FIELDS 53

54 INITIAL CONFORMAL FIELDS 54

55 INITIAL 1150 NcGy 55

56 BOOST FIELDS BLOCKING SOME PTV 56

57 DOSE DISTRIBUTION 57

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60 Base of skull involvement Gamma Knife boost 60

61 UNDER-DOSED AREA BOOST Conclusion, gamma knife boost improved local control without adding toxicity 61

62 GAMMA KNIFE BOOST 62

63 FUTURE DEVELOPMENTS Fast neutrons are capable of producing positron-emitting isotopes in the human body through several nuclear reactions, including 12C(n,2n)11C, 16O(n,2n)15O, 31P(n,2n)30P, 14N(n,2n)13N, 35Cl(n,2n)34mCl, 39K(n,2n)38K (Biggin and Morgan 1971). 63

64 PET IMAGING 64

65 FUTURE DEVELOPMENTS 65

66 FUTURE DEVELOPMENTS 66

67 SUMMARY Neutron radiotherapy has been proven for tumors that radio-resistant Very small classification of tumors, important though! UWMC only operational facility worldwide 67

68 REFERENCES 1. Risler, R. The clinical neutron therapy system (CNTS) at the University of Washington. Power Point Presentation. University of Washington. February, Kubik D. Clinical Neutron Therapy Center. Power Point Presentation. University of Washington. March, Laramore G, Phillips M, DeLaney T. Particle Bean Radiotherapy. In: Halerin M, Perez C, and Brady L, eds. Perez and Brady s Principle and Practice of Radiation Oncology. 5 th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2008: Hall E, Cox J. Physical and Biological Basis of Radiation Therapy. In: Radiation Oncology: Cox J, Ang K eds. Rationale, Technique and Results. 8 th ed. St. Louis, MO: Mosby; Douglas J, Laramore G, Austin-Seymour M, et al. Neutron radiotherapy for adenoid cystic carcinoma of minor salivary glands. Int J Radiat Bio 27: , Rockhill J, Laramore G. Neutron Radiotherapy. In: Clinical Radiation Oncology: Gunderson L, Tepper J eds. Clinical Radiation Oncology. 3 rd ed. Philadelphia, PA: Elsevier. 68

69 REFERENCES 7. Laramore G. The Role of Neutron Radiotherapy in the Treatment of Adenoid Cystic Carcinoma A. Kalet, G. S. Sandison, M. H. Phillips, U. Parvathaneni, Validation of the Pinnacle3 photon convolution-superposition algorithm applied to fast neutron beams J Appl Clin Med Phys (in press). 69

70 THANK YOU! Photo by Richard Walker 70