A Quest for Accuracy and Reproducibility

0731)~021 l/92 $S.Ml + .Ml Copyright 0 1992 American Association of MedIcal Dos!metrists

A QUEST FOR ACCURACY AND REPRODUCIBILITY Design of a Simulation Record CHARLOTTE C. LEWIS,C.M.D. ’and KARL L. PRADOPH.D.* ‘Peninsula General Hospital Medical Center, Radiation Oncology Department, 100 E. Carroll St., Salisbury, MD 2 180 1, *Memorial Hospital and Medical Center, Midland, TX 7970 1 Abstract-This paper describes a simulation record that has been designed for use in most radiation therapy centers. The format is such that it can be used for all machine types and can be transferred easily between centers. The simulation record is separate from the treatment documentation record. It can be reused for several simulations with the addition of one or two inserts. All information needed to reproduce the treatment setup (i.e., positioning, immobilization technique, use of blocks, and photographs of the patient) is well documented. The record prompts the simulation technologist to record field and patient parameters, which are necessary for dose calculations along the central axis and at any other points of interest. Key Words: Simulation, Patient setup, Patient treatment parameters.

INTRODUCTION

THE

FORMAT

This is a four-page, single fold simulation record. The front page includes patient and simulation demographics and patient positioning information. The next page is for documentation of treatment field parameters which will be used for machine setups and central axis and off axis dose calculations. The third page is sectioned for Polaroid photographs of the patient setup and skin marks. The last page is designed for diagrams of the treatment fields.

During simulation, two extremely important tasks take place: the relationship between patient and machine is established; and pertinent treatment setup information is recorded. An appropriate simulation should result in reproducible patient and machine repositioning. Sufficient information should be obtained to allow adequate dosimetry. Clear and complete simulation information is essential for a successful procedure. This proposed form has been designed with the above criteria in mind. Simulation and treatment records tend to be very department oriented; the format and information included in these records usually pertain only to the department in which they are currently being used. Because patients and technologists transfer from one center to another, it is important to have a record that is more universal and easily understood. This record is designed to prompt the technologist to include all information at the time of the simulation. Too little information could result in the delay of treatment or in a repeat simulation. Complete and accurate information is even more crucial when a patient is transferred to another center or when he/she returns for additional treatments at a later date. Routine setups may vary tremendously from institution to institution and are often not well documented. For instance, one department may use the same patient position for all oblique lungs. Because everyone working in that department knows the routine, the position may not be properly documented in the patient record. This recording system will eliminate any guesswork and assumptions by providing full and complete documentation.

Page One: Setup information At the top of the front page (Fig. 1) is the patient information. This includes the therapy number, names of the physician and technologist completing the simulation, the date the patient starts treatments and the appointment time. Below this is the description of the site that has been simulated and the field identification. The patient positioning and immobilization information is also in this section. Commonly used patient positions, immobilization devices, and treatment aids are listed, and the simulation technologist simply checks off those items that apply. This approach prompts the technologist to record all necessary information and essentially results in standardization of positioning. If the patient setup remains exactly the same for the reduced field, the only information to be documented for the reduced field will be the simulation date, start date and time, and the field identification. Should there be minor changes in the setup for the reduced field, these changes could be documented in another color ink on the same page. On the bottom of the page is a section for com3-l

Volume 17, Number 1, 1992

Medical Dosimetry

38

RADIATION

PATIENT

THERAPY SIMULATION

THERAPY NUMBER:

NAME:

SIMULATION

PHYSICIAN: SIMULATION

START

DATE:

SIMULATION DATE: (BOOST)

START

TIME:

START DATE :

START

TIME:

FIELD

POSITION:

ALPHA CRADLE:

YES

HEAD DEVICES:

HEAD CUP

PRONE PILLOW: BREAST BOARD :

1.D.S OTHER

PRONE

SUPINE

TECH:

DATE :

ANATOMICAL SITE: PATIENT

RECORD

NO

AQUAPLAST: BITE

BLOCK

YES

NO

VERT:

HOR :

ANG

NO:

YES

HEIGHT:

HEAD CUP:

HAND BAR:

OTHER: ARM POSITION:

ARM BOARD:

SHOULDER RETRACTOR:

ALONG SIDES: FINGERS

OVER HEAD:

HEIGHT:

RIGHT

LEFT

/CHEST

INTERLOCKED ON ABDOMEN:

OTHER :

FEET POSITION:

OUT : -

TOES IN:

UP: -

DOWN:

SPONGE #

UNDER KNEES/

NO SPONGE

SPONGE I

UNDER ANKLE

SPECIAL

SET-UP

DEVICES:

OTHER :

COMMENTS:

CCL9190 Fig. 1. Radiation

therapy simulation

ments. Changes in setup should be described here. Additional pages can be added to the simulation record if there are several changes in the setup or if another site is simulated.

record:

Page one.

Page Two: Treatment parameters The second page of the simulation record (Fig. 2) will be used by the physics staff to obtain all the information used for the calculation of dose, monitor

Designof a simulationrecord0 C. C. LEWIS and K. L. PRADO RADIATION PATIENT

THERAPY

NAME:

SIMULATION THERAPY

SET UP INFOREATION: DATE : FIELD I.D. FIELD DESCRIPTION:

FLD

FIELD

DATA

1

FLD

39

RECORD

NUMBER:

2

FLD

3

FLD

4

FLD

5

TREATMENT UNIT: BEAM TYPE: BEAM ENERGY: PATIENT SEPARATION: SOURCE TO SKIN DISTANCE: SOURCE TO AXIS DISTANCE: TABLE TO LASER HEIGHT: TREATUENT DEPTH: FIELD SIZE: FIELD Xl: FIELD X2: FIELD Yl: FIELD Y2: CONE SIZE: CUTOUT SIZE: SOURCE TO FILE DISTANCE: GANTRY ANGLE: COLLIMATOR ANGLE: FLOOR ANGLE: STRETCHER ANGLE: TRAY TYPE: BLOCK TYPE: WEDGE ANGLE: WEDGE CODE: TABLE INSERT: COUPENSATOR: BOLUS : CONTOUR TAKEN: POINT DOSE EEASUREEENTS: TEMPLATE : SPECIAL

PHYSICS

REQUESTED: PHOTOS __ FIELD FILM: OUTS I DE IN-HOUSE

DIAGRAM STAMPED POSITIONING PHOTOS PHYSICIAN CHECKED CONSENT FORK SIGNED: TREATMENT RECORD COMPLETED FILES COPIED: POINT DOSE MEASUREMENTS: DESCRIPTION:

POINT

AP

SSD

AP

SEP

PA

--

-_--CCL9/90 Fig. 2. Radiation therapy simulation record: Page two.

SSD

PA

SEP

40

Medical Dosimetry

Volume 17, Number 1, 1992

POLAROIDS FLD

# 1 SITE

I

FLD #

1

1

FLD

# 1 SITE

I

SITE

I

FLD

Fig. 3. Radiation therapy simulation

#

SITE

record: Page three.

Medical Dosimetry

Volume 17, Number I, I992

units, or treatment time. The technologist will refer to this portion to obtain the information that is to be transferred to the treatment record. For each field, or set of fields (e.g., parallel opposed pair) the treatment unit is identified, distances and separations are recorded, field sizes and angles are specified (with allowances for assymetric fields), and beam modifiers are identified. Special physics information is also recorded in this section. A check list is included to assure that all information has been documented in the chart once the simulation is completed and prior to the patient’s leaving. Page Three: Positioning and field photographs The patient positioning photographs and photographs of skin markings should be included for all treatment sites (Fig. 3). These will assist the technologist in reproducing the patient’s setup more precisely. If there are any questions regarding the skin marks, they can be verified with the use these photographs. The photographs that are to be included for each simulation should consist of, as a minimum, one photo taken at a distance and one close-up of each setup site. The photograph taken at a distance should show the patient’s position on the simulation table. All immobilization devices should be in position when the photograph is taken (Fig. 4). The close-up photographs of the skin markings should identify laser marks, central axis cross, setup cross (if it is not same as the central axis), and field borders (Fig. 5). It is best if these photographs are taken “enface” in order to eliminate distortion of the lines by the camera. In addition, electron setup photographs are more precise if they include the patient and the treatment unit in the treatment position. This will demonstrate the relationship of the electron cone to the patient. Each photograph should be labeled with the patient’s name, field identification, treatment number, and date.

Fig. 4. Photograph

of setup site taken at a distance.

Fig. 5. Close-up photograph

of skin markings.

Page Four: Diagrams Diagrams of all ports are to be included in the simulation record (Fig. 6). These are used to demonstrate the location of blocks, and/or wedges in relation to the treatment field. There are commercially available rubber stamps for all anatomical sites. The treatment field outline and blocks can be drawn on the stamped diagram: wedge and bolus information is also included. The position of the wedge can be documented on the diagram in the orientation in which it is to be used. Block changes should be drawn in another color ink, dated, and initialed. Another technique that can be used in place of the stamped diagram (which does not always portray field position accurately) is the use of simulation film photographs. This method will give much more accurate information regarding the exact relationship of anatomy, field borders, and block position if present. This technique may eliminate the need to mail copies of the simulation films when a patient’s records are requested for another center. CONCLUSION

The inability to reproduce a simulation or to complete required dose calculations is often caused by the lack of necessary information. Our simulation record was designed to provide a section to document all information needed for both. Setup technique, diagrams, and photographs are contained in a single-fold format for easier use by the technologist. He/she can take this record into the treatment room to set up the patient without needing the entire chart. The format allows for easier transition when patients are transferred to another center or need to be treated again at a later time. When adopting a record such as this, both format and information can be modified to reflect the procedures most often used at your facility. This will make the record easier to complete.

Design of a simulation record 0 C. C. LEWISand K. L. PRADO

42

DIAGRAMS

------FLD

#

___-_

------

SITE

BLOCK

~---~-~~~~~~--_---____L______~~

WEDGE

BOLUS

FLD

X

SITE

______-_____~~~~-~~-_-------~~~~~--~-------~~~_-FLD

I:

SITE

BLOCK

WEDGE BOLUS

------

------

-_----

BLOCK

WEDGE

BOLUS

--~---_------

FLD t

SITE

BLOCK

-_----. WEDGE

BOLUS

CCL 10/90 Fig.

6. Radiation therapy simulation: Page four.

The combined efforts of the simulation technologist and the physics staff to document all necessary information should decrease the number of errors

and repeat simulations caused from having too little information or from having to retrieve information from more than one place in the chart.