902 Kar 100:136. Therapeutic Systems Below One (1) Mev

Link to law: http://www.lrc.ky.gov/kar/902/100/136.htm
Published: 2015

      902 KAR 100:136.

Therapeutic systems below one (1) MeV.

 

      RELATES TO: KRS

211.842-211.852, 211.990(4)

      STATUTORY

AUTHORITY: KRS 194.050, 211.090, 211.844

      NECESSITY,

FUNCTION, AND CONFORMITY: The Cabinet for Human Resources is authorized by KRS

211.844 to provide by administrative regulation for the registration and

licensing of the possession or use of sources of ionizing or electronic product

radiation and the handling, and disposal of radioactive waste. The purpose of

this administrative regulation is to provide special requirements for the

possession, use, and operation of therapeutic x-ray systems which operate at

energies below one (1) MeV.

 

      Section 1.

Applicability. This administrative regulation shall apply to therapeutic x-ray

systems which operate at energies below one (1) MeV and to persons, equipment

and materials used in connection with the possession, use or operation of the

systems.

 

      Section 2.

Leakage Radiation. If the x-ray system is operated at its leakage technique

factors, the leakage radiation shall not exceed the value given below:

      (1) For contact

therapy systems the leakage radiation shall not exceed 100 milliroentgens per

hour measured five (5) cm anywhere from the tube housing;

      (2) For systems

operating between zero and 150 kVp and which are registered prior to March 2,

1977, the leakage radiation shall not exceed one (1) roentgen in one (1) hour

at one (1) meter from the source;

      (3) For systems

operating between zero and 150 kVp and which are registered after March 2,

1977, the leakage radiation shall not exceed 100 milliroentgens in one (1) hour

at one (1) meter from the source;

      (4) For systems

operating between 151 and 500 kVp the leakage radiation shall not exceed one

(1) roentgen in one (1) hour at one (1) meter from the source; or

      (5) For systems

operating between 501 and 999 kVp the leakage radiation at one (1) meter from

the source shall not exceed one-tenth (0.1) percent of the useful beam one (1)

meter from the source.

 

      Section 3.

Permanent Beam Limiting Devices. Permanent fixed diaphragms or cones used for

collimating the useful beam shall provide the same or higher degree of

protection as required by the tube housing assembly.

 

      Section 4.

Removable Beam Limiting Devices. Removable beam limiting devices shall, for the

portion of the useful beam to be blocked by these devices, transmit not more

than one (1) percent of the useful beam at the maximum kilovoltage and maximum

treatment filter. This requirement does not apply to auxiliary blocks or

materials placed in the useful beam to shape the useful beam to the individual

patient.

 

      Section 5.

Adjustable Beam Limiting Devices. Adjustable beam limiting devices shall meet

the following requirements:

      (1) Devices

installed after March 2, 1977 shall, for the portion of the useful beam to be

blocked by these devices, transmit not more than one (1) percent of the

original beam at the maximum kilovoltage and maximum treatment filter; or

      (2) Devices

installed before March 2, 1977, shall for the portion of the useful beam to be

blocked by these devices, transmit not more than five (5) percent of the

original beam at the maximum kilovoltage and maximum treatment filter.

 

      Section 6.

Filter System. The filter system shall be designed to meet the following

requirements:

      (1) The filters

cannot be accidentally displaced at possible tube orientation;

      (2) Each filter

shall be marked as to its material of construction and its thickness and, for

wedge filters, the wedge angle shall appear on the wedge or wedge tray; and

      (3) The

radiation at five (5) centimeters from the filter insertion slot opening does

not exceed thirty (30) roentgens per hour under operating conditions.

 

      Section 7. Focal

Spot Marking and Assembly Immobilization. The tube housing assembly shall be

marked so that it is possible to determine the location of the focal spot to

within five (5) millimeters and the marking shall be readily accessible for use

during calibration procedures. In addition the assembly shall be capable of

being immobilized during stationary treatments.

 

      Section 8.

Contact Therapy Beam Block. Contact therapy tube housing assemblies shall have

a removable shield of at least five-tenths (0.5) mm lead equivalent material at

100 kVp that can be positioned over the entire useful beam port during periods

that the beam is not in use.

 

      Section 9. Beam

Monitor System. Therapy x-ray systems registered after March 2, 1977 which are

capable of operating above 150 kVp shall be provided with a beam monitoring

system which meets the following requirements:

      (1) The beam

monitoring system shall have a detector interlock to prevent incorrect

positioning;

      (2) The beam

monitoring system shall have a display at the control panel from which the dose

at a reference point in soft tissue can be calculated;

      (3) The control

panel display shall maintain the administered dose reading until intentionally

reset to zero;

      (4) If a system

malfunctions or electrical power failure occurs the dose administered to a

patient prior to the system's malfunction or power failure can be accurately

determined;

      (5) The beam

monitoring system shall not allow irradiation until a preselected value of

exposure has been made at the treatment control panel;

      (6) The beam

monitoring system shall be capable of independently terminating irradiation if

the preselected exposure has been reached; and

      (7) The control

panel display shall not have scale multiplying factors and shall utilize a

design that displays increasing dose by increasing numbers.

 

      Section 10.

Timers. Therapeutic x-ray systems shall be provided with timers which meet the

following requirements:

      (1) The timer

shall have a display at the control panel with a preset time selector and an

elapsed time indicator;

      (2) The timer

shall be a cumulative timer which activates with the production of radiation

and retains its reading after irradiation is interrupted or terminated. It

shall be necessary to zero the elapsed time indicator after irradiation is

terminated and before irradiation can be reinstated.

      (3) The timer

shall terminate irradiation after a preselected time has elapsed if a dose

monitoring system present has not previously terminated irradiation.

      (4) The timer

shall permit accurate presetting and determination of exposure times as short

as one (1) second and shall not permit an exposure if set at zero; and

      (5) The timer

shall not activate until the shutter is open if the irradiation is controlled

by a shutter mechanism.

 

      Section 11.

Control Panel. The control panel, in addition to other display requirements of

this administrative regulation, shall meet the following requirements:

      (1) The control

panel shall indicate the presence of electrical power, the possibility of tube

activation, the production of x-rays, and the actual kilovoltage and current

across the tube;

      (2) A means shall

be provided for terminating an exposure at once;

      (3) A locking

device shall be provided which prevents unauthorized use of the x-ray system;

and

      (4) A display

shall be provided on systems registered after March 2, 1977 which indicates

specific filter(s) in the useful beam.

 

      Section 12.

Control Panels Which Control More Than One (1) Tube. If a control panel may

energize more than one (1) x-ray tube then the following requirements shall be

met:

      (1) Only one (1)

x-ray tube may be activated at one (1) time;

      (2) The control

panel shall indicate which x-ray tube is energized; and

      (3) Each x-ray

tube shall indicate whether that tube is energized.

 

      Section 13.

Source-to-skin Distance. A means shall be provided to determine the

source-to-skin distance to within one (1) centimeter.

 

      Section 14.

Shutter Control. Unless it is possible to bring the x-ray output to the

prescribed exposure parameters within five (5) seconds, the entire useful beam

shall be automatically attenuated by a shutter having a lead equivalency not

less than that of the tube housing. Systems using shutter control shall meet

the following requirements:

      (1) The shutter

shall be electrically controlled by the operator from the control panel; and

      (2) An

indication of shutter position shall appear at the control panel. The control

panel shall indicate whether the shutter is open or closed.

 

      Section 15.

Facility Design and Shielding Requirements for X-ray Systems Capable of

Operating Above Fifty (50) kVp. In addition to the shielding adequate to meet

the requirements of 902 KAR 100:105, the following requirements shall also be

met:

      (1) Provision

shall be made for two (2) way aural communication with the patient from the

control room; however, if excessive noise levels make aural communication impractical

other methods of communication shall be used;

      (2) Windows,

mirror systems, or closed-circuit television viewing screens or an equivalent

system shall be provided to permit continuous observation of the patient during

irradiation and shall be so located that the operator may see the patient and

the control panel from the same position. If the primary viewing system is by

electronic means (e.g., television) an alternate viewing system shall be

available as a back-up if electronic failure occurs;

      (3) The therapy

room shall be so constructed that persons may be able to escape from within;

and

      (4) Facilities

which contain an x-ray system which may be operated above 150 kVp shall meet

the following requirements:

      (a) Protective

barriers shall be fixed barriers, except for entrance doors or beam

interceptors.

      (b) The control

panel shall be located outside the treatment room;

      (c) Doors of the

treatment room shall be electrically connected to the control panel so that

x-ray production cannot occur unless the door is closed;

      (d) Doors

referred to in paragraphs (a) and (c) of this subsection, shall be interlocked

electrically so that they are closed before treatment can be initiated or

continued. If the irradiation is interrupted by a door opening, it shall not be

possible to restore the machine to operation without closing the door and

reinitiating irradiation by manual action at the control panel; and

      (e) If a door

referred to in paragraph (d) of this subsection is opened while the x-ray tube

is activated, the exposure at a distance of one (1) meter from the source shall

be reduced to less than 100 milliroentgens per hour.

 

      Section 16.

Surveys and Calibrations. New facilities and existing facilities not previously

surveyed, shall have a radiation protection survey made by or under the

direction of a qualified expert. A survey shall also be conducted after changes

in the facility which might cause a significant increase in a radiation hazard.

      (1) The

registrant shall obtain a written report of this survey from the qualified

expert and a copy of this report shall be transmitted by the registrant to the

cabinet within thirty (30) days of receipt of the report. The survey and report

shall indicate instances where the installation, in the opinion of the qualified

expert, is in noncompliance of applicable administrative regulations.

      (2) The

calibration of an x-ray system shall be performed at intervals not to exceed

one (1) year and after changes or replacement of components which are likely to

change the radiation output. This calibration shall be performed by or under

the direction of a qualified expert who is physically present at the facility

during the calibration. Calibration of the radiation output shall be performed

with a calibrated dosimetry system which is directly traceable to national

standards and which shall have been calibrated within the preceding two (2)

years. Records of calibrations shall be maintained by the registrant for five

(5) years. The calibration shall include at least the following determinations:

      (a) Verification

that the system is operating in compliance with the design specifications;

      (b) The exposure

rate as a function of field size, technique factors, filter, and treatment

distance used;

      (c) The

congruence between the radiation field and field indicated by the localizing

device if localizing devices are used for radiation therapy; and

      (d) The

uniformity of the largest radiation field used.

      (3) The

calibration determinations prescribed in subsection (2) of this section shall

be performed in a manner that the dose at a reference point in soft tissue can

be calculated within plus or minus five (5) percent of the intended absorbed

dose.

      (4) A copy of

the most recent x-ray system calibration shall be available at or in the area of

the control panel.

      (5) Therapeutic

x-ray systems capable of operation at greater than 150 kVp shall also have spot

checks performed which meet the following:

      (a) The spot

check procedures shall specify the frequency at which tests or measurements are

to be performed. The spot check procedures shall specify that the spot check

shall be performed during the calibration specified in subsection (2) of this

section. The acceptable tolerance for each parameter measured in the spot check

compared to the value for that parameter determined in the calibration

specified in subsection (2) of this section shall be stated;

      (b) The spot

check methods shall be in writing and shall have been designed by a qualified

expert. A copy of the procedures shall be submitted to the cabinet prior to its

implementation;

      (c) If a

qualified expert does not perform the spot check measurement, the results of

the spot check measurements shall be reviewed by a qualified expert within

fifteen (15) days;

      (d) If a spot

check indicates a significant change in the operating characteristics of a

machine, the machine shall be recalibrated as required by subsection (2) of

this section;

      (e) Records of

spot check measurements shall be maintained for two (2) years after completion

of the spot check measurements and necessary corrective actions;

      (f) The spot

check procedures shall specify the frequency at which tests of measurements are

to be performed the spot check procedures shall specify that the spot check

shall be performed during the calibration specified in subsection (2) of this

section shall be stated;

      (g) The cause

for a parameter exceeding a tolerance set by the qualified expert shall be

investigated and corrected before the system is used for patient irradiation;

and

      (h) If a spot check

involves a radiation measurement, the measurement shall be obtained using a

system satisfying the requirements of subsection (2) of this section or which

has been intercompared with a system meeting those requirements within the

previous year.

 

      Section 17.

Operating Procedures. Therapeutic x-ray systems shall be operated so the

following requirements are met:

      (1) The facility

shall be operated in compliance with any limitations indicated by the radiation

protection survey which have been approved by the cabinet;

      (2) The x-ray

system shall not be used in the administration of radiation therapy unless the

requirement of Section 16 of this administrative regulation has been met;

      (3) Therapeutic

x-ray systems shall not be left unattended unless the locking device required

by Section 10(3) of this administrative regulation is set to prevent activation

of the useful beam;

      (4) If a patient

is required to be held in position for radiation therapy, mechanical supporting

or restraining devices shall be used;

      (5) The tube

housing assembly shall not be held by hand during operation unless the system

is designed to require holding and the potential difference of the system does

not exceed fifty (50) kVp. In this instance the holder shall wear protective

gloves and apron of not less than five-tenths (0.5) mm lead equivalency at 100

kVp;

      (6) No

individual other than the patient shall be in the treatment room unless the

individual is protected by a barrier sufficient to meet the requirements of 902

KAR 100:020. No individual other than the patient shall be in the treatment

room during exposures from x-ray systems operating above 150 kVp; and

      (7) The x-ray

system shall not be used in the administration of radiation therapy unless the

requirements of subsections (2) and (5)(d) of this section have been met. (3

Ky.R. 570; eff. 3-2-77; Am. 12 Ky.R. 1402; eff. 3-4-86; 18 Ky.R. 1559; eff.

1-10-92.)
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