Overview of Clinical and Research Activities at Georgetown University Hospital

Transcription

1 Overview of Clinical and Research Activities at Georgetown University Hospital Dalong Pang, Ph.D. Department of Radiation Medicine Georgetown University Hospital

2 Clinical Operation Two Varian linear accelerators Varian IX Varian Trilogy

3 3-D CRT IMRT VMAT Electron

4 Two Cyberknives

5 SRS, SBRT lung prostate Brain

6 One Gamma-Med HDR unit Mostly Gyn using vaginal cylinders

7 Prostate Seed Implant B&K ultrasound, Variseed planning, Pd-103, either Mono (125 Gy) or boost (76 Gy)

8 Cs-137 LDR Implant Ir-192 LDR Implant

9 Electronic Brachytherapy Carl Zeiss Intra-Beam System (IORT) Robotic arm applicators X-ray source

10 Intra-Beam RT Surgical removal of the tumor Applicator with X-ray probe positioned in the lumpectomy site. Treatment last for about 20 to 50minute to deliver 20Gy in single fraction to the applicator surface

11 Basic Characteristics A single fraction RT to lumpectomy wall X-ray energy: 50 kvp Dose: 20 Gy at cone surface and 7 Gy at 1-cm depth Treatment time (20-60 minutes) depends on cone size (1.5 cm to 6 cm)

12 SIR-Spheres Y-90 Resin Microspheres Use of Radioactive Y-90 resin spheres for the treatment of metastatic colorectal cancer in the liver.

13 Y-90: beta emitter, half life: 64 hours, mean energy: MeV, mean range: 2.5 mm. Intra-arterial delivery Amount of activity depends on patient size, weight, liver lobe volume and lesion volumes BSA m ht m wt(kg)

14 Basic and Clinical Research 1. Atomic Force Microscopy (AFM) investigation of DNA fragmentation by high-let charged particles DNA is the critical cellular target of radiation; DNA DSBs are the most lethal DNA lesions. Higher LET leads to higher RBE- rationale for heavy charged particle therapy High-LET radiation induces complex DSB lesions that are more difficult to repair.

15 Method for Quantifying DSBs: AFM

16 Irradiation of DNA Molecules at Various Laboratories Georgetown: Electron AFRRI: Neutron Oak Ridge: Beryllium Chiba Japan: Argon

17 AFM Measurement of Irradiated DNA e - n 0 Be ++ Ar ++

18 DNA Fragment Size Distributions of Electron and Neutron Irradiated DNA e - n0 Be ++ Ar ++

19 Average DSB and DSB Spatial Distribution can be derived from the size distribution profiles. DSB clustering can be demonstrated <DSB>= n/n 0 Sparely: Low-LET Clustered: High-LET

20 Significance of Research 1. Direct visualization of individual DNA fragments 2. Experimental demonstration of clustered DNA DSB 3. Correlation of DNA clustering with LET of radiation 4. Data aid in theoretical modeling of DNA damage: Monte Carlo simulation, Microdosimetry 5. DNA damage repair

21 2. Circulating Cell-Free DNA: a Potential Biomarker for Cancer Diagnosis and Treatment Response? 1. Cancer Diagnosis 2. Treatment Response 3. Similar genetic or mutational information in DNAs extracted

22 Quantitative-PCR is the primary method for studies of cfdna: Concentration Mutation DNA fragment size index Cancer vs. no cancer Concentration is significantly greater in patients with cancer There is a difference in fragment size index Treatment response Successful treatment results in reduced concentration

23 Hypothesis: DNA fragment size distributions may reveal more information on tumor characteristics AFM used to measure DNA sizes

24 Our Focus: Radiation Treatment Response Blood samples collected from patients with pancreatic cancer, metastatic colorectal cancer, prostate cancer before and after treatments. blood spin Extraction of ccfdna and AFM imaging Measurement of fragment size distribution

25 Construction of a Nanofluidic device for rapid DNA size measurement (T. Kole, MD) In collaboration with NIST nanofabrication Lab Working on image process software for automatic fragment size measurement

26

27 4. Treatment Planning Automation: Knowledge-Based Optimization Continuation and expansion of OVH-driven treatment planning optimization (Binbin Wu, PhD) Application in Cyberknife Planning Application of IMRT database to VMAT planning Application in plan generation for different institutions

28 OVH-based optimization aid in Cyberknife planning A data base containing 500 cyberknife plans OVH calculated, PTV, OAR volumes compiled New plans generated retrospectively and prospectively Comparison to existing plans showed equal or better plan quality

29 Comparison of OVH Plans with Clinical Plans Mean dose to bladder reduces from 17.4Gy in CPs to 13.8Gy in APs 20.7% (3.6Gy) reduction Mean dose to rectum reduces from 16.8Gy in CPs to 14.8Gy in APs 12% (2Gy) reduction

30 Use of one institution s database to generate plans for another institution 1. H&N plans from a Dutch hospital: 45 patient H&N plans using 7 beam IMRT. SIB-IMRT, 68Gy and 50.3Gy. 2. New plan generated for each patient using JUH database 178 H&N SIB-IMRT plans with three-dose-level: 70Gy, 63Gy and 58.1Gy. 3. Comparison between the plans on DVH demonstrates comparable quality between the OVH-driven plans and the Dutch plans.

31 CP 80 PTV50.3 PTV68 80 AP CP AP Cord Dose (Gy) Larynx CP AP Brainstem Mandible Dose (Gy) AP CP 60 Oral cavity I Parotid C Parotid Dose (Gy) Dose (Gy)

32 New Development Construction for a Mevion S250 proton system underway

33 Treatment room Planar X-ray panels Mobile CT

34 Project Progress current December, 2016

35 Thank You!