Is It Safe For Patients With Implanted Cardiac Devices To Undergo Proton Beam Therapy.ppt

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					  Is It Safe For Patients With Implanted
Cardiac Devices To Undergo Proton Beam

  Rohan Samson, MD, Junaid A. Ahmed, MD, Alice Schroeder,
  RN, Cynthia Gist, ACNP, Ali Nasur, MD, Naseer Nasser, MD,
    Robert Kim, MD, David Nabert, MD and Steve Hsu, MD.

             University of Florida, Jacksonville, FL

• Nothing to Disclose

•   Proton therapy is a type of particle therapy which uses a beam of protons to
    irradiate diseased tissue, most often in the treatment of cancer.

•    A cyclotron strips hydrogen atoms, accelerates and directs the resulting protons
    towards tumors.

•   As protons slow in tissue they deliver the majority of their energy as ionizing

•   This process may also produce scatter radiation that impacts cardiac devices.
                              The Cyclotron

•   Through electrolysis, protons are taken from water and injected into the cyclotron
    (cylindrical structure at center) which accelerates protons to nearly the speed of light. The
    protons are guided through the beam line at right.
                           The Beam Line

The protons travel through the beam line, guided by electromagnets, into one of four treatment
                                  The Gantry

Proton therapy is delivered while you lie on the treatment table. A gantry rotates to deliver
    therapy precisely to the tumor site.
                      Bragg Peak

• Described by William
  Bragg over 100 years

• Depth is dependent on
  the energy of the
  proton beam

• This energy can be
  controlled very precisely
       Diseases Treated by Proton Therapy

•   Urological cancers, especially prostate cancer
•   Lung cancer
•   Head and neck cancer
•   Pediatric malignancies
•   Bone and soft tissue sarcomas
•   Cancer of the eye and other disorders such as macular degeneration
•   Brain cancer and cancer of the central nervous system
                Proton Beam Statistics

•   As of 2008, 55,000 patients have been treated with proton therapy worldwide

•   In the United States, there are five facilities offering this treatment

•   Locations where PBT is being offered in the US:

     The Harvard Cyclotron laboratory at Massachusetts General Hospital
     The Proton Treatment Center at Loma Linda University Medical Center (LLUMC)
     M.D. Anderson Proton Therapy Center in Houston
     University of Pennsylvania's proton facility in Philadelphia
     University of Florida's Proton Therapy Institute in Jacksonville
  Effect of Proton Beam on cardiac
• Current implanted cardiac devices are prone to
  electromagnetic interference (EMI).

• There is limited literature in the interaction between cardiac
  devices and proton beam therapy.
            AIM of our study

• To study the Effects of Proton Beam Therapy
  on Appropriate Functioning of Implantable
  Cardiac Pacemakers and Defibrillators

•   Prospective study

•   Evaluated patients with Pacemakers, Implantable Cardioverter Defibrillators (ICD)
    undergoing proton beam therapy at our Proton Therapy Institute from 2006
    through 2010.

•   Device interrogation done at : Baseline (prior to starting therapy)
                                   Immediately post initial therapy
                                   Weekly during the entire treatment duration

•   Inferential statistics in the form of univariate tests (T-tests, Chi square) were
    utilized to compare the group with device resets to the group without device
    resets on the characteristics collected.
Demographics and Clinical Characteristics

Percentage of pts with        Site of Proton beam Therapy
ICDs vs Pacemakers            Prostate = 27 pts
ICD = 12 pts                  Chest = 2 pts
PM = 19 pts                   Head/Neck=2 pts

Type of ICD implanted:            Device Manufacturers:
Single Chamber ICD = 1 pt         Medtronic = 18 pts
Dual Chamber ICD = 8 pts          St Jude = 5 pts
BiV-ICD = 3 pts                   BSC = 7 pts
                                  ELA = 1 pt
Results – Device Reprogramming
Analysis of Device Reprogramming

•   All resets occurred in ICDs, not Pacemakers: Statistically Significant

•   There was an increased incidence of resets in patients with higher number
    of leads: Statistically Significant (p=0.013)

•   No statistically significant differences were noted between patients with
    device resets and those without device resets when comparing other
    Site of Therapy
    Radiation Dose

•   All resets occurred in ICDs, none in Pacemakers

•   Higher incidence of resets in patients with more number of leads.

•   Device resets observed predominantly in Medtronic devices may be a biased observation
    due to the large number of Medtronic devices implanted in study population (58% overall).

•   Despite small numbers of patients, we are the first to report observations or significant
    findings of any kind involving device resets in patients receiving Proton beam Therapy.

•   As this category of patients grows over time, it will become important to understand the
    interactions of Proton Beam Therapy and Cardiac Devices, especially since patients are
    dependent on the appropriate functioning of their devices, especially ICDs.
Thank you !

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