ML24064A167

Draft for ACMUI Review - Akesis Galaxy Rti Gsr Licensing Guidance

ML24064A167
Person / Time
Issue date:	11/30/2023
From:	Shaw D, Katherine Tapp NRC/NMSS/DMSST/MSEB
To:
Armstead L
References
Download: ML24064A167 (18)

Text

Akesis Galaxy RTi Licensing Guidance

November 30, 2023, Revision 0

U.S. Nuclear Regulatory Commission Contact Daniel Shaw (301) 415-3649; K atie Tapp (301) 415-0236 MedicalQuestions.Resource@nrc.gov

Table of Contents

1. 10 CFR 35.1000 Use............................................................................................................... 1

2. Licensing Guidance................................................................................................................. 2

3. General.................................................................................................................................... 3 3.1. Sensitive Security-Related Information............................................................................. 3 3.2. 10 CFR Part 37................................................................................................................. 3 3.3. Radionuclides, Form, Possession Limits, and Purpose of Us e......................................... 3 3.4. Facility Address and Description [10 CFR 30.33(a)(2) and 10 CFR 35.12(b)(1)].............. 3

4. Training and Experience.......................................................................................................... 4 4.1. Authorized Individuals [10 CFR 30.33(a)(3); 10 CFR 35.12( b)(1); 35.50; 35.51; and 35.690]...................................................................................................................................... 4 4.1.1. Authorized User.............................................................................................................. 4 4.1.2. Authorized Medical Physicists.................................................................................... 5 4.2. Radiation Safety Officer.................................................................................................... 6

5. Licensing Commitments........................................................................................................... 6 5.1. Written Directive: [10 CFR 35.40]...................................................................................... 7 5.2. Specific Information on Radiation Safety Precautions and Instructions:........................... 8

[10 CFR 35.12(d)(3)(i)].............................................................................................................. 8 5.3. Physical Presence Required by 35.615(f)(3)................................................................... 12 5.4. Procedures required by 35.610 and 35.645 [10 CFR 30.33(a) (3) and 10 CFR 35.12(b)(2)].............................................................................................................................. 12 5.5. Published Protocols Accepted by Nationally Recognized Bod ies................................... 13 5.6. Full Inspection and Service of the Akesis Galaxy RTi Un it [10 CFR 35.655].............. 13

6. Notes to Licensees................................................................................................................ 14 6.1. Alterations to the Akesis Galaxy RTi........................................................................... 14 6.2. Changes in Physical Conditions of Use.......................................................................... 14 6.3. Notification for AUs and AMPs........................................................................................ 1 4 6.4. Grandfathering................................................................................................................ 15 6.5 Revisions to Existing Akesis Galaxy RTi Radiation Safet y Programs to Conform...... 15 to Future Changes in Licensing Guidance and Additional Safety R ecommendations from the Manufacturer........................................................................................................................... 15

7. Note to Regulators................................................................................................................. 16 7.1. Inspection Frequency...................................................................................................... 16 7.2. Program Code................................................................................................................. 16

8. Paperwork Reduction Act Statement..................................................................................... 16

9. Public Protection Notification................................................................................................. 16

1. 10 CFR 35.1000 Use

The term Stereotactic radiosurgery is commonly used to indicate the application of radiation beams coming from many directions. The Akesis Galaxy RTi is a gamma stereotactic radiosurgery (GSR) unit that contains thirty Cobalt-60 sources with approximately 6000 curies (Ci) total initial source activity. The unit is paired with an Image Guidance System (IGS) that uses reference images to move the treatment couch to the correc t target position for lesion treatment. During treatment, the radiation sources will be aligned with the user selected secondary collimators. The source and the collimating structure s rotate simultaneously during treatment to form thirty non-overlapping convergent 360° gamma ray arcs. Since all thirty beams are directed towards the target, the target will receive a high radiation dose proportional to the total irradiation time. The surrounding normal tissues o nly receive a transient irradiation.

The target spot is sometimes referred to as the focal-spot or focus. The description focus describes the concentration of all beams in one intersecting po int on the rotational axis but ignores the fact that the radiation beams diverge from the sour ce and cover an extended volume at the intersection point. Before the treatment, the pat ient (with head frame or mask attached) will be positioned on the treatment couch. Based on t he head frame or mask, CT-scans and/or MRI-scans, the target shape and patient position ( X, Y, Z coordinates) will be confirmed. After the operator accepts the treatment parameters, the control system automatically executes the planned treatment. No further operat or intervention is required during a normal treatment.

Note, Akesis uses the terms focus, focal-spot, target, and targ et-spot interchangeably for the focal point.

Although the Akesis Galaxy RTi is a GSR unit, the device inclu des a number of engineering changes that make the components and operation significantly di fferent from the GSR units currently regulated in 10 CFR Part 35, Subpart H, Photon Emitt ing Remote Afterloader Units, Teletherapy Units, and Gamma Stereotactic Radiosurgery Units. These engineering changes include the absence of helmets, relative helmet factors, helmet microswitches, hydraulic backups, trunnions and a trunnion centricity point. In addition, Akesis Galaxy RTi engineering changes include:

• A beam-collimating system for collimating, focusing and shield ing the radiation beams, consisting of a shielding hemisphere, a tungsten-alloy shieldin g block, 30 rotating radiation sources, a source drawer, and a source carrier.

• A moveable (X, Y, Z) treatment couch that is used with the pat ient supine during the treatment process that moves the patient to the target position (focal point so that the target in the treatment plan coincides with the focal point of the device.

• As part of the IGS, the Akesis Galaxy RTi includes the addit ion of an x-ray tube system mounted onto the unit to take cone beam computed tomogra phy (CBCT) images to obtain patient positioning and verification with use of refe rence images.

• The Akesis Galaxy RTi unit can immobilize the patients head with either a rigid-fixation stereotactic head frame or with a double shell mask positioning system manufactured by MacroMedics. The immobilization of the patients head is achie ved via the headframe interface system that includes a frame-locking interface assemb ly (U-Frame) and adapter (L-Frame). The U-frame is permanently fixed to the trea tment couch and

1 provides a fixed reference of table position to beam center. Wh en mated to the patients headframe, the specified positional accuracy of the beam is ach ieved by precise table movements. Either an independently 510(k) cleared and compatibl e mask-based or a rigid-fixation head frame must be properly attached to the head frame interface

• The Akesis Galaxy RTi will use the real-time image-guided rad iation therapy (RT-IGRT) system to monitor movements of the patient during setup a nd treatment while immobilized by the head frame interface.

As a result, the Akesis Galaxy RTi is regulated under 10 CFR P art 35, Subpart K, Other Medical Uses of Byproduct Material or Radiation From Byproduct Material. [10 CFR 35.1000]

2. Licensing Guidance

Applicants may refer to NUREG-1556, Volume 9, Revision 3, Cons olidated Guidance About Material Licenses: Program-Specific Guidance About Medical Use Licenses, as it provides overall licensing guidance for all medical uses of byproduct ma terial, including information on how to submit facilitys address and description and applicable model procedures for audits, occupational dose monitoring programs, and surveys. Applicants should also refer to https://www.nrc.gov/reading-rm/sensitive-info/materials.html for information regarding submissions of information containing sensitive security-relate d information, such as information about quantities and locations of radioactive materials at lice nsed facilities.

This guidance provides applicants with an acceptable means of s atisfying the requirements for a license for the use of the Akesis Galaxy RTi, however, it is n ot intended to be the only means of satisfying requirements for a license. The applicant must submit the information required by 10 CFR 30.33 and 10 CFR 35.12 as described below. The applicant must submit additional information and commitments requested below or may, unless the information is specifically required by regulation, submit alternative commitments for revi ew by the U.S. Nuclear Regulatory Commission (NRC) staff to determine whether the regu latory requirements are met.

The licensee commitments are incorporated into the applicants license by conditions and will be reviewed during routine inspections. Applicants are reminded th at licenses issued pursuant to 10 CFR 35.10001 must still meet the general requirements in 10 CFR Part 35, Subparts A, B, C, H, L, M and N, except as specified in this guidance. Additional ly, applicants must meet applicable requirements of 10 CFR Parts 19, 20, 30, 37 and 71.

The Akesis Galaxy RTi makes use of an integrated CBCT imaging system (i.e the IGS) to ensure the patient is properly positioned for and during treatm ent. The specific license issued by the NRC does not authorize the licensee to possess and use the CBCT imaging system. This authorization must be obtained from the applicable state agency having jurisdiction over computed tomography scanning equipment. The CBCT is not license d or registered by the NRC. However, because the CBCT is critical to verifying the acc uracy of the patient positioning, NRC will require licensees to commit to certain quality assuran ce (QA) measurements as outlined in the section titled, Specific Information on Radiat ion Safety Precautions and Instructions.

1 Medical uses of byproduct material licensed under 10 CFR 35.1000 are designated as Compatibility Category D. Agreement States are not required to adopt these regulations for purposes of compatibility.

2

3. General

3.1. Sensitive Security-Related Information

Certain sensitive security-related information such as quantiti es and locations of radioactive materials at licensed facilities are no longer released to the public. Submission of this type of information in an application should be marked as specified in Regulatory Issue Summary 2005-31, Revision 1, NRC Regulatory Issue Summary 2005-31, Control of Security Re lated Sensitive Unclassified Non-Safeguards Information Handled by Individuals, Firms, and Entities Subject to NRC Regulation of the Use of Source, Byproduct, and Special Nuc lear Material.

Additional information on procedures handling and marking secur ity-related information and any updates are available at https://www.nrc.gov/reading-rm/sensitive-info.html.

3.2. 10 CFR Part 37

Applicants requesting authorization for the Akesis Galaxy RTi unit must comply with 10 CFR Part 37 before installing sources for this unit.

Members who have not been granted unescorted access in accordan ce with 10 CFR Part 37 must be escorted at all times, such as individuals who service the CBCT component or are inspecting (i.e., NRC or Agreement State inspectors) the Akesis Galaxy RTi must be escorted at all times unless they fall under the relief granted under 10 CFR 37.29. For more information, see NUREG-1556, Volume 9, Revision 3, Consolidated Guidance Ab out Materials Licenses:

Program-Specific Guidance About Medical Use Licenses; NUREG-21 55, Implementation Guidance for 10 CFR Part 37, Physical Protection of Category 1 and Category 2 Quantities of Radioactive Material; and NUREG-2166, Physical Security Best Practices for the Protection of Risk-Significant Radioactive Material.

3.3. Radionuclides, Form, Possession Limits, and Purpose of Us e

Per the requirements of 10 CFR 35.12, the applicant shall ident ify the radionuclides, chemical/physical form, requested maximum possession limit, and purpose of use. For guidance to meet the requirement, refer to NUREG 1556, Volume 9, Revision 3 Contents of and Application additional information. NRC Form 313, Application for Materials License may be used to submit this information. For example, the following provides the format for an acceptable request:

Radionuclides Cobalt-60 NRC Form 313, Section 5.a.)

Chemical/Physical Form Sealed sources (Manufacturer and Model Number, e.g.,

(NRC Form 313, Section 5.b.) XXXXXXX)

Maximum Possession Limit 200 curies per source not to exceed 6000 curies total (or (NRC Form 313, Section 5.c.) 10000 curies during source exchange)

Authorized Use For 10 CFR 35.1000 medical use in the Akesis Galaxy (NRC Form 313, Section 6) RTi gamma stereotactic radiosurgery unit

3.4. Facility Address and Description [ 10 CFR 30.33(a)(2) and 10 CFR 35.12(b)(1)]

3 Provide an address of use, submit a facility diagram, and descr iption of the location where the Akesis Galaxy RTi GSR unit will be used or stored.

4. Training and Experience

4.1. Authorized Individuals [10 CFR 30.33(a)(3); 10 CFR 35.12(b)(1); 35.50; 35.51; and 35.690]

The NRC has determined that individuals meeting the guidance pr ovided below will be considered qualified and authorized for the Akesis Galaxy RTi GSR unit. Applicants may also submit alternative training and experience commitments to be re viewed on a case-by-case basis by the NRC staff. The alternative information should incl ude an explanation of why the applicant believes the alternative information demonstrates tha t the individuals are qualified to be authorized individuals.

Because there are minimal Akesis Galaxy RTi units approved for medical use in the United States at the time this licensing guidance was initially publis hed in 2024, there are a limited number of preceptors available to sign attestations. Therefore, the NRC is postponing requiring a written attestation until Month/Day/Year. At that time, attes tations will be required for individuals who do not hold certification by a recognized speci alty board or are not already authorized for use of other gamma stereotactic radiosurgery uni ts. The NRC will continue to review the availability of preceptors and may revise this guida nce if it determines that sufficient preceptors have not become available. In addition, all individu als seeking authorization for use of the Icon' must submit documentation of successful completion of required training.

4.1.1. Authorized User

Applicants and licensees should identify each authorized user (AU) of the Akesis Galaxy RTi GSR unit and provide documentation of their training and experi ence in the use of the unit. The NRC Form 313A (AUS), Authorized User Training and Experience and Preceptor Attest ation (for uses defined under 35.400 and 35.600) [ 10 CFR 35.490, 35.491, and 35.690], or other formats may be used to document this training and experience. T he physician will be considered qualified for use of the Akesis Galaxy RTi GSR unit if the individual meets the following:

1) Is listed on a license or permit (NRC, Agreement State, Broa d Scope License or NRC Master Materials License) as an AU for 10 CFR 35.600 medical us e of a GSR unit; an AU for 10 CFR 35.1000 medical use of the Akesis Galaxy RTi ; or is board certified by a recognized board listed on the NRCs Web site Specialty Board Certifications Recognized by NRC Under 10 CFR Part 35 under section 10 CFR 35.690, Training for use of remote afterloader units, teletherapy units, and gamma s tereotactic radiosurgery units, or meets the criteria in 10 CFR 35.690(b)(1) and (2) for GSR unit use;

AND

2) Received documented training in hands-on device operation, s afety procedures, and clinical use, which includes headframe or mask fitment, prepari ng treatment plans and calculating treatment doses and times, for the Akesis Galaxy R Ti GSR unit. If the

4 individual is already an AU for a GSR unit, in accordance with 10 CFR 35.690(c), this training must also include the differences in the device operat ion, safety procedures, and clinical use of the Galaxy RTi and the other GSR unit(s) that t he individual is authorized to use. This training requirement may be satisfied by satisfact ory completion of a training program provided by the Akesis vendor or by receiving training supervised by an AU or authorized medical physicist (AM P), as appropriate, who is auth orized for the Akesis Galaxy RTi use;

AND

3) Obtain a written attestation that the individual has satisfa ctorily completed the above training and is able to independently fulfill the radiation saf ety related duties as an AU for the Akesis Galaxy unit. The written attestation must be signed by a preceptor AU who is authorized for the Akesis Galaxy RTi unit. The written attestation is not require d for individuals who hold certification by a recognized specialty bo ard.

4.1.2. Authorized Medical Physicists

Identify each AMP for the Akesis Galaxy RTi GSR unit and provide documentation o f his/her training and experience in the use of the unit. The NRC Form 313A (AMP), Authorized Medical Physicist Training and Experience and Preceptor Attestation [ 10 CFR 35.51], or other formats may be used to document this training and experience. The medic al physicist shall be considered qualified for use of the Akesis Galaxy RTi GSR unit, if the individual meets the following:

1) Is listed on a license or permit (NRC, Agreement State, Broa d Scope License or NRC Master Materials License) as an AMP for GSR unit use; or is boa rd certified by a board listed on the NRCs Web site Specialty Board Certifications Recognized by NRC Under 10 CFR Part 35 under section 10 CFR 35.51, Training for an Authorized Medical Physicist; or meets the criteria in 35.51(b)(1) and (2) for gamma stereotactic radiosurgery unit use;

AND

2) Received documented training in hands-on device operation, s afety procedures, clinical use, and the operation of a treatment planning system for the A kesis Galaxy RTi unit. If the individual is already an AMP for a GSR unit, in accordance with 10 CFR 35.51(c),

this training must also include the differences in the device o peration, safety procedures, clinical use, and the operation of a treatment planning system of the Akesis Galaxy RTi and other GSR units for which the individual is authorized. Thi s training requirement may be satisfied by satisfactorily completing either a training pro gram provided by the Akesis vendor or by training supervised by an AMP authorized for Akesi s Galaxy RTi use;

AND

3) Obtained a written attestation that the individual has satis factorily completed the above training and is able to independently fulfill the radiation saf ety-related duties as an AMP for the Akesis Galaxy RTi unit. The written attestation must b e signed by a preceptor

5 AMP authorized for the Galaxy RTi unit. The written attestation is not required for individuals who hold certification by a recognized specialty bo ard.

4.2. Radiation Safety Officer

Identify the Radiation Safety Officer (RSO) with responsibility for the Akesis Galaxy RTi GSR unit and provide documentation of his/her training and experien ce in radiation safety for the unit.

NRC Form 313A (RSO), Radiation Safety Officer Training and Experience and Precept or Attestation [10 CFR 35.50], or other formats may be used to document this training and experience. The NRC recognizes that some applicants with new in stallations could have an individual who will have RSO responsibilities for the Akesis Ga laxy RTi unit but may not have access to an operational unit at the time of the radiation safe ty, regulatory issues, and emergency procedures training. For this reason, the applicant m ay commit that the individual will complete supplemental hands-on radiation safety and emerge ncy procedure training before first patient treatment using the GSR unit. The individual shal l be considered qualified to be the RSO for the Akesis Galaxy RTi GSR unit if the individual meets the following:

1) Is listed as an RSO on an NRC or Agreement State license (or NRC Master Materials License permit) authorizing GSR unit medical use, or is board c ertified by a board listed on the NRCs Web site Specialty Board Certifications Recognized by NRC Under 10 CFR Part 35 under section 10 CFR 35.50, Training for Radiation Safety Officer, or meets the criteria 35.50(b)(1), or 35.50(c)(1) or (2) for GSR unit use;

AND

2) Received documented training in the radiation safety, regula tory issues, and emergency procedures for the Akesis Galaxy RTi GSR unit. If the individu al already has RSO responsibilities for a GSR unit, in accordance with 10 CFR 35.50(e), the training must also include instruction in the differences in the radiation sa fety, regulatory issues, and emergency procedures of the Akesis Galaxy RTi unit and other GSR units for which the individual has RSO responsibility. This training requiremen t may be satisfied by completing training that is pr ovided by the Akesis vendor or supervised by an individual (RSO or AMP or AU) that is authorized for the Galaxy RTi unit. The individual should complete or commit to complete supplemental hands-on radiation safety and emergency procedures training on an operational Akesis unit before first use of the unit for patient treatment;

AND

3) Obtained a written attestation that the individual has satis factorily completed the above training and is able to independently fulfill the radiation saf ety-related duties as a RSO for the medical use of the Akesis Galaxy RTi GSR unit. The wri tten attestation must be signed by a preceptor RSO, AMP, or AU authorized for the Akesis unit. The written attestation is not required for individuals who hold certificat ion by a recognized specialty board.

5. Licensing Commitments

6 5.1. Written Directive: [10 CFR 35.40]

The Akesis Galaxy RTi stereotactic radiosurgery unit delivers a therapeutic dose of radiation from byproduct material and under 10 CFR 35.40 requires a written directive. Calculation of the dose to the treatment site is dependent on the shaping of the r adiation field at the focal point by selection of different collimators. Therefore, to assure the d ose is delivered in accordance with the AUs direction, the written directive should include the co llimator specifications, the treatment plan of the single shot or the multi-shot irradiation according to the position and coordinates of the target. The applicant should provide the fol lowing commitment:

For the Akesis Galaxy RTi GSR unit use, the written directiv e will contain the patient or human research subject's name; the total dose; the treatment site; dose per fraction; number of fractions; and the X, Y, Z target coordinate values; gamma angle; beam rotation start and stop angle and collimator size for each trea tment shot within an anatomically distinct treatment site.

When a written directive is needed, licensees are required unde r 10 CFR 35.41(a)(2) to have procedures that provide high confidence that each administratio n is in accordance with the written directive. Under 10 CFR 35.41(b)(4) these procedures are required to address, among other things, verification that any computer-generated dose cal culations are correctly transferred into the control system of GSR units authorized by 10 CFR 35.60 0. This verification is also applicable to GSR units regulated under 10 CFR 35.1000. For the Akesis Galaxy RTi GSR unit, the computer-generated dose calculations for each shot (i.e., each set of target coordinates) should also include the collimator settings for th at shot. For this reason, the applicant should provide the following commitment:

For the Akesis Galaxy RTi GSR unit, procedures that provide h igh confidence that each administration is in accordance with the written directive will address verification that any computer-generated dose calculations are correctly tra nsferred into the Akesis Galaxy RTi control system.

A number of medical events with earlier models of GSR units res ulted from movement of the head frame or head frame pins during coughing and other patient movement. As part of its program to provide high confidence that the administration is i n accordance with the written directive, the applicant should develop written procedures for the following: (1) pausing treatment and checking the patient set-up if a patient is obser ved to move during the course of a treatment shot and (2) visually checking the patient set up eac h time the gamma angle is changed or at the end of the treatment run, whichever comes fir st.

The applicant should confirm the following for the Akesis Galax y RTi:

In order to provide high confidence that the administration i s in accordance with the written directive our program will include written procedures f or: (1) verification of the integrity of the fixation before starting the treatment (2) pau sing treatment and checking the patient set-up if a patient is observed to move during the course of a treatment and every time the real-time image-guided radiation therapy (RT-IGR T) system pauses the system due to patient movement outside the set limit and (3) vi sually checking the patient set up each time the gamma angle is changed or at the e nd of the treatment run, whichever comes first.

7 5.2. Specific Information on Radiation Safety Precautions and Instructions:

[10 CFR 35.12(d)(3)(i)]

The applicant must submit the information required by 10 CFR 35.12(d). Because the Akesis Galaxy RTi unit is a GSR unit, the applicant may simplify its submission by confirming the following:

For use of the Akesis Galaxy RTi, we will meet the following requirements for a GSR unit in 10 CFR Part 35, Subpart H:

Section 35.600,

Section 35.605 (and retain records of the information described in Section 35.2605 for 3 years),

Section 35.610 (and retain procedures described in Sections 35.610(a)(4) and (d)(2) for the retention period stated in Section 35.2610, and retain instructions described in 35.610(d) for the retention period stated in Secti on 35.2310.

Section 35.615 (a) through (d), 35.615(f)(4), and 35.615(g)

Section 35.615(f)(3) (with the modifications listed below),

Section 35.630 (and retain a copy of the information described in Section 35.2630 for the duration of the license),

Section 35.635 (with modifications discussed below and retain a copy of the information described in Section 35.2632 with modifications discussed below for the retention period of 3 years),

Section 35.645 (with modifications discussed below and retain a copy of the information described in Section 35.2645 with modifications discussed below for 3 years),

Section 35.655, (and retain records of the inspection as described in Section 35.2655)

Section 35.657,

Section 35.690.

Unlike earlier GSR units licensed under 10 CFR 35.600, the sour ces in the Akesis Galaxy RTi unit are in a movable source drawer. Therefore, radiation surve ys required in 10 CFR 35.652(b) will be required following any repairs to the source driving un it or to other electronic or mechanical component that could expose the source, reduce the s hielding around the sources, or compromise the radiation safety of the unit or the sources. The driving unit includes a motor and gearbox for the outer, primary collimator (source carrier), a motor and gearbox for the inner, secondary collimator, feedback encoders for both, secondary fee dback encoders, a position indicator, tensioners, timing belts, and two electromagnetic cl utch brakes. The system determines the relative position of the sec-ondary collimator a nd the source carrier through the position information feedback from the motor en-coders. The sys tem compares the information

8 from the motor encoders to determine whether the rotating hemis pheres relative position is consistent with the treatment plan and to trigger an interlock should an inconsistency occur. The tensioners are designed to adjust the tension of the timing bel ts. The manufacturer states that the timing belts must be replaced annually by Akesis service pe rsonnel.

The spot test and full calibration test should include assessin g whether the patient docking systems function correctly to place the mechanical center) of t he stereotactic frame at the radiation focal point, to know the size of the radiation focal point by confirming the collimator sizes, and to test the precision with which the treatment site could be placed at the radiation focal-spot and the accuracy of the dose calculations. New test s should be performed as part of the revised spot test and full calibration test to assess these basic properties for the Akesis Galaxy RTi unit.

Some of the measurements in 10 CFR 35.635 and 35.645 cannot be performed and the results of such determinations and tests cannot be recorded as describe d in 10 CFR 35.2632 or 35.2645 because the components specified in those regulatory pr ovisions do not exist in the Akesis Galaxy RTi unit. For example, for treatment with the Ak esis Galaxy RTi unit, the patients head is either immobilized with the aid of a stereota ctic head frame or with the aid of a double shell mask that is uniquely shaped to each patient. Rega rdless of the method of immobilization, the patients head is attached in an immovable position to the treatment couch, and the treatment couch itself is moved (X, Y, and Z directions ) over small distances to center the treatment site at the radiation focal-spot.

The individual removable collimator helmets in earlier GSR unit s have been replaced by four permanently installed independently rotating collimators in the Galaxy RTi unit. The sources, housed in a source drawer, and the collimating structures rotat e simultaneously during treatment to form thirty non-overlapping convergent 360° gamma ray arcs. The collimator system contains four different sets of fixed collimator apertur es (4 mm, 8 mm, 14 mm, and 18 mm) as well as shielded position (Beam-off). The collimator ape rture is set so that the focal point remains constant independent of the collimator used. Ther efore, the location and function of the collimators, the patient bed, the docking device, the fr ame adapter, the mask adapter, and the source exposure indicator light on the device are critical to the safe use and proper functioning of the Akesis unit and should be tested as part of the spot-checks (referred to as QA checks in the operators manual) and full calibration test. Als o, the condition and function of the clearance test tool and QA test tool are critical to determine the location of the radiation focal point, table location, and frame adapter function. For Akesis unit, the verification of the accuracy of the patient positioning with the CBCT is critical a nd therefore the QA measurements described in the vendor-supplied Instructions for Use shall be performed exactly as stated.

The Akesis Galaxy RTi will use the real-time image-guided syst em (IGS) to monitor movements of the patient during setup and treatment while immob ilized by the mask. The imaging focus of IGS coincides with the focal-spot of the treat ment device. The equipped IGS can register the acquired images with the reference images in t he treatment plan and send the position deviation to the Recording and Verification System (RV S). According to the position deviation sent by IGS, the control system moves the treatment couch to the correct target position, and then treatment can be performed. The RVS will pau se the patient treatment in the event that the treatment couch position is out of tolerance dur ing the irradiation process by +/-0.5 mm in X, Y, and Z directions.

The applicant should confirm the following for the Akesis Galax y:

9 We will follow the survey requirements of 10 CFR 35.652 and ma ke the surveys at installation of a new source and following repairs to the drivi ng unit or other electronic or mechanical component that could expose the source, reduce the s hielding around the sources, or compromise the radiation safety of the unit or the sources. The driving unit includes a motor and gearbox for collimating structure, a motor and gearbox for the source carrier, position indicating device, a tensioner, and tw o clutch brakes. The two driving devices are used to drive the collimating structure and source carrier, respectively. We will retain information described in Section 3 5.2652 for the period stated in Section 35.2652.

We will follow the applicable fu ll calibration requirements of 10 CFR 35.635 and the spot-check requirements in 10 CFR 35.645 and retain the informa tion described in 10 CFR 35.2632 for each full calibration and 10 CFR 35.2645 for ea ch check except for those involving helmets, helmet factors, helmet micro-switches, trunnions, and hydraulic backup of the treatment table retraction system. We will keep e ach record of the full calibration and spot-checks for 3 years.

Before the first use of the Akesis Galaxy RTi unit each day, we will confirm that the docking device is securely mounted to the treatment couch (table) and t hat the frame adapter can be correctly docked in the docking device. This test and the descr iption of the record of the test will be included in the spot-check procedures. The test will also be performed during the full calibration measurements of the Ak esis Galaxy RTi unit. We wil l keep each record of the results of this test performed during the full calibration meas urement and spot-check for 3 years.

Before each patient use, the patient is immobilized with the stereotactic U-frame, we will confirm that the L-frame adapter is functioning correctly and can be attached correctly to the coordinate frame. This test and the descriptio n of the record of the test will be included in the spot-check procedures. The test will al so be performed during the full calibration measurements of the Akesis Galaxy RTi unit. W e will keep each record of the results of this test performed during the full calibrati on measurement and spot-check for 3 years.

On a monthly basis, we will confirm that the location of the r adiation focal point (isocenter accuracy), with respect to the treatment couch posit ion, is within the specifications provided by the manufacturer. This test and the description of the record of the test will be included in the spot-check procedures. The test will also be performed during the full calibration measurements of the Akesis Galaxy RTi unit. We will keep each record of the results of this test performed during the fu ll calibration measurement and spot-check for 3 years.

On a monthly basis, we will confirm that the location of the t reatment couch at a number of off-center positions is within the collision specifications provided by the manufacturer.

This test and the description of the record of the test will be included in the spot-check procedures. The test will also be performed during the full cal ibration measurements of the Akesis Galaxy RTi unit. We will keep each record of the re sults of this test performed during the full calibration measurement and spot-chec k for 3 years.

Approximately every six months (with exact date subject to ven dor service availability),

we will confirm that the beam collimating system is within appr opriate tolerance limits.

This test and the description of the record of the test will be included in the spot-check

10 procedures. The test will also be performed during the full cal ibration measurements of the Akesis Galaxy RTi unit. We will keep each record of the re sults of this test performed during the full calibration measurement and spot-chec k for 3 years.

During installation and approximately every six months (with e xact date subject to vendor service availability, i.e., planned maintenance), we wil l confirm that the vendor will verify that the location of the radiation focal point, wit h respect to the treatment couch, is within the specificat ions using measurements conducte d in an off-centered position. This test and the description of the record of the te st will be included in the spot-check procedures. The test will also be performed during t he full calibration measurements of the Akesis Galax y RTi unit. We will keep each record of the results of this test performed during the full calibration measurement and spot-check for 3 years.

We confirm that if the frame adapter or mask adapter fails to perform as designed, we will remove it from service until repaired.

We confirm that if the source carrier or treatment couch posit ioning fail to perform as designed, we will lock the control console in the off position and not use the unit except as necessary to repair, replace, or check the malfunctioning sy stem.

We confirm that removal or major repair of the components asso ciated with the source carrier and collimator assemblies will be considered a major re pair of the source assembly and will require full calibration.

Before the first use of the Akesis unit each day, when using t he CBCT system during patient setup, we will confirm that the precision of the CBCT s ystem is within the specifications provided by the manufacturer. This test and the description of the record of the test will be included in the spot-check procedures. The test will also be performed during the full calibration measurements of the Akesis unit. We will keep each record of the results of this test performed during the full calibration measurement and spot-check for 3 years.

Before each patient use, and when the patient is immobilized w ith a mask, we will confirm that the mask fits the patients head, the mask adapter is func tioning correctly and can be attached correctly to the docking device. This test and the des cription of the record of the test will be included in the spot-check procedures. The test wi ll also be performed during the full calibration measurements of the Akesis unit. We will k eep each record of the results of this test performed during the full calibration measurement and spot-check for 3 years.

Before each patient use of the Akesis Galaxy RTi unit, we wil l confirm that the IGS is working properly. This is done by verifying that a IGS starts r eal-time image guidance through use of the Akesis provided phantom. The test will also be performed during the full calibration measurements of the Akesis Galaxy RTi unit. W e will keep each record of the results of this test performed during the full calibrati on measurement and spot-check for 3 years.

On a monthly basis, we will confirm that the CBCT image qualit y is satisfactory. The description of the test and the record of the test will be incl uded in the spot-check procedures. The test will also be performed during the full cal ibration measurements of

11 the Akesis Galaxy RTi unit. We will keep each record of the re sults of this test performed during the full calibration measurement and spot-chec k for 3 years.

We confirm that if the CBCT-system and/or the IGS system fails to function as specified by the manufacturer, we will have the system(s) repaired or rep laced before the next patient treatment requiring the proper function of these system.

Every year, we will have the timing belt replaced by Akesis se rvice personnel.

5.3. Physical Presence Required by 35.615(f)(3)

As stated in 10 CFR 35.615(f)(3), an AU and an AMP are required to be physically present throughout all patient treatments involving GSR units. However, unlike the Leksell Gamma Knife models, the Akesis Galaxy RTi unit has additional safety funct ions and utilizes a completely automated treatment system to deliver dose to the pa tient. Internal collimation alleviates the need to change collimator helmets and patients a re positioned as required by the treatment plan by moving the treatment couch. The CBCT and IGS ensure the patient is properly positioned prior to treatment and any movement during treatment causes the sources to move to the blocked position. An auto dry-run test is acco mplished prior to patient treatments. The Akesis Galaxy RTi has twenty-two (22) independ ent interlocks to ensure patient safety during the treatment. These interlocks ensure th e room is safe, the patient is in the proper position and secure, and that the beam and collimato rs are in position and indicated per TPS. As such, the physical presence of the AU throughout al l patient treatments required by 10 CFR 35.615(f)(3) for other types of GSR units is unnecessary for the Akesis Gal axy RTi unit, provided an AMP and a physician, under the supervision of an AU, are present throughout the duration of all treatments.

Therefore, Akesis Galaxy RTi unit licensees should confirm th ey are meeting the requirements in 10 CFR 35.615(f)(3) or the following:

1) An authorized user and an authorized medical physicist will be physically present during the initiation of all patient treatments involving the A kesis Galaxy RTi unit;

2) An authorized medical physicist and either an authorized use r or a physician, under the supervision of an authorized user, who has been trained in the operation and emergency response for the unit, will be physically present dur ing continuation of all patient treatments involving the Akesis Galaxy RTi unit; and

3) An authorized user will return to the Akesis unit console if there is an interruption of treatment to evaluate the patient, to review any information re lated to an abnormal situation, and to ensure that the treatment is being delivered in accordance with the treatment plan and written directive prior to re-initiation of the treatment.

5.4. Procedures required by 10 CFR 35.610 and 35.645 [10 CFR 30.33(a)(3) and 10 CFR 35.12(b)(2)]

The applicant is required by 10 CFR 35.12(b)(2) to provide the procedures in 10 CFR 35.610, 35.642, 35.643, and 35.645, as applicable. For the Akesis Galaxy RTi radiation safety program only the procedures in 10 CFR 35.610 and 35.645 are appropriate.

12 The Akesis Galaxy RTi unit does not have helmet microswitches o r trunnion centricity.

Therefore, the applicant will not be required to provide spot-c heck procedures for those particular components. However, the applicant should provide ad ditional daily spot-check procedures for proper operation of the frame adapter or mask ad apter docking device, additional monthly spot-check procedures for the location of th e radiation focal point with respect to the treatment couch position, and collision table lo cation, and a six month spot-check procedure (with exact date subject to vendor service availabili ty) for verification of correct sector movement and location.

The applicant must provide a copy of:

• Safety procedures and instruction for the Akesis Galaxy RTi u nit and

• Spot-check procedures for unit.

5.5. Published Protocols Accepted by Nationally Recognized Bod ies

Full calibration measurement procedures for GSR units are requi red by 10 CFR 35.635(d) to be performed in accordance with pub lished protocols accepted by na tionally recognized bodies.

However, the Akesis Galaxy RTi unit contains components and fe atures that are not addressed in the full calibration procedures accepted and publi shed by nationally recognized bodies. In this case, the applicant may use procedures develope d by the manufacturer.

The applicant should confirm the following:

We will perform full calibration measurement procedures in acc ordance with published protocols accepted by nationally recognized bodies, except when nationally recognized bodies have not published required full calibration procedures for components and features of the Akesis Galaxy RTi unit. In the absence of publ ished protocols for the Akesis Galaxy RTi unit accepted by nationally recognized bodie s, we will use procedures developed by the manufacturer.

5.6. Full Inspection and Service of the Akesis Galaxy RTi Un it [10 CFR 35.655]

The NRC requires the full inspecti on and servicing of GSR units to assure proper functioning of the source exposure mechanism and other safety components. Whil e a number of systems external to the radiation vault can be inspected and serviced p rior to source replacement, areas inside the vault can only be inspected and serviced in the abse nce of the sources. Therefore, the full inspection and service of the Akesis Galaxy RTi unit can only be performed at source exchange.

The applicant should confirm the following:

We will commit to have each Akesis Galaxy RTi GSR unit fully inspected and serviced during source replacement to assure proper functioning of the s ource exposure mechanism and other safety components. The interval between eac h full-inspection servicing shall not exceed 7 years for each unit.

This inspection and servicing will only be performed by persons specifically licensed to do so by the Commission or an Agreement State.

13 We will retain records of the information described in Section 10 CFR 35.2655 for the duration of use of the unit.

6. Notes to Licensees

6.1. Alterations to the Akesis Galaxy RTi

This licensing guidance is based on the sealed source and devic e (SS&D) safety evaluation in registration certificate XX-XXXX-X-XXX-X. Modification of the s ources, the device (including the CBCT approved in the SS&D certificate), or the source-device co mbination, will require an amended SS&D certificate (or safety evaluation by the broad sco pe medical use licensee) that addresses the conditions of use and safety of the modified Akes is unit.

6.2. Changes in Physical Conditions of Use

If the physical conditions of use exceed those reported in the SS&D certificate, the limited specific medical use licensee should request an amendment for t he new conditions, and a broad scope licensee should perform its own engineering and rad iation safety evaluation addressing those differences.

6.3. Notification for AUs and AMPs

The NRC recognizes that if an AU or AMP satisfies the training and experience listed in the NRCs licensing guidance for the Akesis Galaxy RTi unit and is currently listed on a Commission or Agreement State medical use license or permit for the GSR unit, the AU or AMP should be allowed to work under a different license for the med ical use of the Akesis Galaxy RTi unit. A limited specific medical use applicant initially ap plying for authorization for the medical use of the Akesis Galaxy RTi unit or an existing licen see applying for an amendment may request authorization to notify the NRC in the future that it has permitted an AU to work at its facility without the need to request an additional license amendment, provided the following conditions are met:

1) The AU or AMP meets the training and experience criteria lis ted in NRCs licensing guidance for the Akesis Galaxy RTi unit; and

2) The AU or AMP is currently listed for the Akesis Galaxy RTi unit use on a Commission or Agreement State license, a permit issued by a Commission mas ter material license, a permit issued by a Commission or Agreement State licensee of a broad scope, or a permit issued by a Commission master material license broad sco pe permittee; and

3) The licensee provides NRC a copy of the license or permit on which the AU or AMP was originally listed for the Akesis Galaxy RTi unit; and

4) The licensee provides documentation to NRC for each AU or AM P of the above listed conditions no later than 30 days after the date that the licens ee allows the AU or AMP to work as an AU or AMP for the Akesis Galaxy RTi unit.

If this authorization is approved, these notification condition s will be incorporated as license conditions in the licensees license.

14 6.4. Grandfathering

If a licensee adopts this revision of the Akesis Galaxy RTi tr aining and experience criteria, AUs, AMPs, or RSOs who are currently authorized for the medical use of the Galaxy RTi under previous criteria do not have to meet the revised criteria for the device.

6.5. Revisions to Existing Akesis Galaxy RTi Radiation Safety Programs to Conform to Future Changes in Licensing Guidance and Additional Safety Reco mmendations from the Manufacturer

Requesting authorization in accordance with this guidance will permit a licensee to make certain changes under 10 CFR 35.26, Radiation protection program changes, to the Akesis Galaxy RTi GSR unit safety program that might otherwise require a lice nse amendment.

This licensing guidance and safety recommendations from the man ufacturer may be revised as the regulator and manufacturer gain additional experience regar ding medical use of the Akesis Galaxy RTi GSR unit. Therefore, in contrast to 10 CFR 35.26, a licensee already authorized to use the Akesis Galaxy RTi GSR unit and committed by license co ndition to follow the provisions in this guidance and the operators manual existing at the time of commitment must apply for and receive an amendment to its license prior to making changes to conform to the revised guidance and additional radiation safety recommendation s.

An applicant initially applying for authorization for medical u se of the Akesis Galaxy RTi GSR unit (or a licensee applying for an amendment to conform with t his revision of the guidance) may request authorization to allow future changes to its radiation safety program, provided the following conditions are met:

1. The revision is in compliance with the regulations of the NR C or Agreement State;

2. The revision is based upon NRCs current guidance for the Ak esis Galaxy RTi GSR unit medical use under 35.1000 use posted on the NRC web site or the current operators manual and additional safety recommendations from th e manufacturer;

3. The revision has been reviewed and approved by the licensee s RSO and management; and

4. The affected individuals are instructed on the revised progr am before the change is implemented; and

5. The licensee will retain a record of each change for 5 years ; and

6. The record will include a copy of the appropriate licensing guidance, the old procedure, the new procedure, the effective date of the change, and the si gnature of the licensees management representative who reviewed and approved the change.

If the NRC approves this authorization, these conditions will b e incorporated as license conditions in the licensees license. This may be done by incor porating the commitments in the tie down condition.

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7. Note to Regulators

7.1. Inspection Frequency

Licenses authorizing Akesis Galaxy RTi units should be inspect ed every two years. Per to Inspection Manual Chapter 2800, licenses authorizing emerging technology in 10 CFR 35.1000 are assigned a Priority 2 inspection code.

7.2. Program Code

The NRC regions should use program code 02240.

8. Paperwork Reduction Act Statement

The information collections contained in this guidance are cove red by the requirements of 10 CFR Parts 30, 32 and 35, which were approved by the Office of Management and Budget (OMB), approval numbers 3150-0017, 3150-0001, and 3150-0 010, as well as, 3150- 0120 for filling out the NRC Form 313.

9. Public Protection Notification

The NRC may not conduct or sponsor, and a person is not require d to respond to, a request for information or an information collection requirement, unless th e requesting document displays a currently valid OMB control number.

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