intravascular brachytherapy presentation

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UToledo IVBT Presentation

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Jason Hudson Radiation Protection and Regulations Summer 12

INTRAVASCULAR BRACHYTHERAPY (IVBT)

BACKGROUND

Restenosis

Common occurrence after endovascular procedures.

Vascular surgery, cardiac, surgery, angioplasty

In-Stent Restenosis (ISR)Implantation of stents may initiate neointimal hyperplasia leading to phenomenon of ISR Drug Elluting Stents (DES) release antiproliferative drug to help prevent neoint. hyp. IVBT employs ionizing radiation for same purpose. In the US:

DES only for de novo lesions IVBT only for ISR Complementary modes of treatment ISR still occurs in DES, esp. in patients with complex lesions and other medical conditions (diabetes)

FDA APPROVAL

Randomized, controlled clinical trials

Brachytherapy using beta or gamma emitters is highly effective in decreasing the incidence of recurrent ISR, as measured angiographically and by intravascular ultrasound. Decreased incidence of major adverse cardiac events (primarily need for further revascularization Three brachytherapy systems approved by the FDA for treatment of instent restenosis :

Checkmate system from Cordis Corporation Beta Cath system from Novoste Corporation Galileo system from Guidant Corporation All three systems are afterloading systems by means of which sealed raddioactive brachytherapy sources are manually or automatically advanced into a delivery catheter previously positioned inside the patient

CORDIS CHECKMATE

Utilizes only gamma emitter clinically used in IVBT thus far, Ir192

Sources consist of a number of seeds inside a nylon ribbon Sources manufactured by Best Medical International Treatment times for IVBT are typically 15 to 40 min. Delivery device is a cylindrical lead storage pig Sources manually advanced by radiation oncologist into a specially designed noncentering intraarterial catheter.

FIG. 1. Schematic showing (a) a single 192Ir seed, and (b) 6-seed 192Ir train in nylon ribbon. The solid black area indicates the radioactive Pt/ Ir core at the center of each seed. The gray area around the black shows the stainless steel encapsulation around the core

NOVOSTE BETA CATH

Utilizes the first approved beta particle IVBT source, Sr-90/Y-90

Source consists of a string (train) of Sr-90/Y-90 seeds. Seeds stored in a handheld delivery device and advanced by closed-loop hydraulic system, which uses sterile saline to advance and retract seeds into and out of a noncentered catheter. Two source sizes have been used, 5 F and a newer 3.5 F.

FIG. 2. Schematic showing (a) 5 F single seed of 90Sr/ 90Y and an 8-seed train with gold markers on the ends, and (b) 3.5 F single seed of 90Sr/ 90Y and an 8-seed train with Pt/ Ir markers at the ends in a stainless steel wire jacket.

GUIDANT GALILEO

Utilizes the beta emitter P-32

Consists of a computercontrolled afterloader, similar to a conventional HDR unit, equipped with a P-32 wire source. Uses perfusion centering catheters. Only system approved for source pullback, i.e., stepping the source to treat longer lesions.

FIG. 3. (a) Schematic of the 20 mm Guidant 32P wire source. (b) Schematic of the 27 mm Guidant 32P wire source.

CHAPTER 3701:1-58 MEDICAL USE OF RADIOACTIVE MATERIALS

Inventory and leak testing 3701:1-58-27 Requirements for possession of sealed sources and brachytherapy sources(A) A licensee in possession of any sealed source or brachytherapy source shall follow the radiation safety and handling instructions supplied by the manufacturer. (B) A licensee in possession of a sealed source shall: (1) Test the source for leakage before its first use unless the licensee has a certificate from the supplier indicating that the source was tested within six months before transfer to the licensee; and (2) Test the source for leakage at intervals not to exceed six months or at other intervals approved by the director, United States nuclear regulatory commission, or an agreement state. (C) To satisfy the leak test requirements of this rule, the licensee shall measure the sample so that the leak test can detect the presence of one hundred eighty-five becquerels (0.005microcurie) of radioactive material in the sample. (D) A licensee shall retain leak test records in accordance with paragraph (A) of rule 3701:1-58-80 of the Administrative Code.

CHAPTER 3701:1-58 MEDICAL USE OF RADIOACTIVE MATERIALS

3701:1-58-27 Requirements for possession of sealed sources and brachytherapy sources (contd)(E) If the leak test reveals the presence of one hundred eighty-five becquerels (0.005 microcurie) or more of removable contamination, the licensee shall: (1) Immediately withdraw the sealed source from use and store, dispose, or cause it to be repaired in accordance with the requirements in Chapter 3701:1-38 of the Administrative Code, and (2) File a report within five days of the leak test in accordance with rule 3701:1-58103 of the Administrative Code. (F) A licensee need not perform a leak test on the following sources: (1) Sources containing only radioactive material with a half-life of less than thirty days; (2) Sources containing only radioactive material as a gas; (3) Sources containing 3.7 megabecquerels (one hundred microcuries) or less of beta or gamma-emitting material or 0.37megabecquerel (ten microcuries) or less of alpha-emitting material; (4) Seeds of iridium-192 encased in nylon ribbon; and (5) Sources stored and not being used. However, the licensee shall test each such

CHAPTER 3701:1-58 MEDICAL USE OF RADIOACTIVE MATERIALS

3701:1-58-27 Requirements for possession of sealed sources and brachytherapy sources (contd)(G) A licensee in possession of sealed sources or brachytherapy sources, except for gamma stereotactic radiosurgery sources, shall conduct a semi-annual physical inventory of all such sources in its possession. The licensee shall retain each inventory record in accordance with paragraph (B) of rule 3701:1-58-80 of the Administrative Code.

CHAPTER 3701:1-58 MEDICAL USE OF RADIOACTIVE MATERIALS

3701:1-58-30 Use of sources for manual brachytherapyA licensee shall use only brachytherapy sources for therapeutic medical uses: (A) As approved in the Sealed Source and Device Registry; or (B) In research in accordance with an active investigational device exemption application accepted by the United States food and drug administration provided the requirements of rule 3701:1-58-17 of the Administrative Code are met.

CHAPTER 3701:1-58 MEDICAL USE OF RADIOACTIVE MATERIALS

3701:1-58-45 Brachytherapy sources accountability(A) A licensee shall maintain accountability at all times for all brachytherapy sources in storage or use. (B) As soon as possible after removing sources from a patient or a human research subject, a licensee shall return brachytherapy sources to a secure storage area. (C) A licensee shall maintain a record of the brachytherapy source accountability in accordance with rule 3701:1-58-88 of the Administrative Code.

CHAPTER 3701:1-58 MEDICAL USE OF RADIOACTIVE MATERIALS

3701:1-58-48 Calibration measurements of brachytherapy sources

(A) Before the first medical use of a brachytherapy source, a licensee shall have: (1) Determined the source output or activity using a dosimetry system that meets the requirements of paragraph (A) of rule 3701:1-58-60 of the Administrative Code; (2) Determined source positioning accuracy within applicators; and (3) Used published protocols currently accepted by nationally recognized bodies to meet the requirements of paragraphs (A)(1) and (A)(2) of this rule. (B) Instead of a licensee making its own measurements as required in paragraph (A) of this rule, the licensee may use measurements provided by the source manufacturer or by a calibration laboratory accredited by the American Association of Physicists in Medicine (AAPM) that are made in accordance with paragraph (A) of this rule. (C) A licensee shall mathematically correct the outputs or activities determined in paragraph (A) of this rule for radioactive decay at intervals consistent with one percent radioactive decay. (D) A licensee shall retain a record of each calibration in accordance with rule 3701:158-89 of the Administrative Code.

CHAPTER 3701:1-58 MEDICAL USE OF RADIOACTIVE MATERIALS

3701:1-58-50 Therapy-related computer systems for manual brachytherapy

The licensee shall perform acceptance testing on the treatment planning system of therapy-related computer systems in accordance with published protocols accepted by nationally recognized bodies. At a minimum, the acceptance testing must include, as applicable, verification of: (A) The source-specific input parameters required by the dose calculation algorithm; (B) The accuracy of dose, dwell time, and treatment time calculations at representative points; (C) The accuracy of isodose plots and graphic displays; and (D) The accuracy of the software used to determine sealed source positions from radiographic images.

CHAPTER 3701:1-58 MEDICAL USE OF RADIOACTIVE MATERIALS

3701:1-58-51 [Effective 1/1/2012] Training for use of manual brachytherapy sourcesExcept as provided in rule 3701:1-58-21 of the Administrative Code, the licensee shall require an authorized user of a manual brachytherapy source for the uses authorized under rule 3701:1-58-43 of the Administrative Code to be a physician who: (A) Is certified by a medical specialty board whose certification process has been recognized by the director, United States nuclear regulatory commission, or an agreement state, and who meets the requirements in paragraph (B)(3) of this rule. The names of board certifications which have been recognized by the director, United States nuclear regulatory commission, or an agreement state will be posted on the United States nucl

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