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Energy as well as applicator size and shape utilized in over 200 intraoperative electron beam procedures
Inf J Radialion OncologyBid. Phys.. Vol. 15, pp. 1041-1042 Printed in the U.S.A. All rights reserved.
0360-3016/88 $3.00 + .OU Copyright Q 1988 Pergamon Press plc
??Technical Innovations and Notes
ENERGY AS WELL AS APPLICATOR SIZE AND SHAPE UTILIZED IN OVER 200 INTRAOPERATIVE ELECTRON BEAM PROCEDURES EDWIN C. MCCULLOUGH, PH.D. AND LEONARDL. GUNDERSON,M.D. Division of Radiation Oncology, Mayo Clinic/Foundation, Rochester, MN 55905, U.S.A. treatments were given with 6 and 9 MeV electrons respectively (Fig. 1). The 30 degree beveled circular cones accounted for almost half of those used (Fig. 2). The 0 and 15 degree circular cones were about equal in frequency and each accounted for approximately 20% of the total usage. Elliptical shaped cones had an overall use factor of about 12% (25/2 14) with about equal frequency of flat and beveled ends. The use of rectangular cones has been rare (6/2 14) since the elliptical cones were commissioned. However, we note that rectangular cones should be available for para-aortic IORT. The fractional utilization pattern of circular cones (Fig. 3) indicated that only 20% of utilization (for all three types of circular cones, that is, flat, 15 and 30’ beveled) occurred for cone diameters below 6 cm. Figures 2 and 3 indicate that a minimal set of circular cones for intraoperative electron beam radiation therapy would consist of circular diameters from 6 to 9 cm in 5 mm steps, one set with flat ends and a second set with beveled ends (e.g. at 20’). With this complement of cones, approximately 70% of patients could receive near optimal IORT. Obviously, a complete set of circular cones (ends at 0, 15 and 30 degrees) combined with elliptical and rectangular ones would provide the same flexi-
The Mayo Clinic currently combines external beam photons with intraoperatively administered electron beam boosts (IORT) for locally advanced malignancies for which standard treatment approaches achieve inadequate local control. A linear accelerator* with variable electron energies (6, 9, 12, 15 and 18 MeV) is used in conjunction with a set of methyl methacrylatet applicators (cones) of varying size and shape (Table 1). As a result of inquiries about electron energy as well as cone size and shape utilization, an analysis of these factors has been carried out for 2 14 consecutive IORT fields in 190 patients (see Table 2 regarding anatomic distribution). The majority of treatments were given with electron energies of 12 MeV and greater. Only 2 and 27 (of 2 14)
Table 1. Intraoperative applicator (cone) sizes and shapes in use at Mayo Clinic Shape
Size
Circular 0
4 through 9 cm in 0.5 cm increments 4 through 8.5 cm in 0.5 cm increments 5 through 8.5 cm in 0.5 cm increments
0
::O Elliptical 0
6~ 11,7X 6X 11,7x
2s
Rectangular 0 20”
12,9X 12,9x
12cm
12cm
100
8X9,8X 12,8X 15cm 8~ 12,8X 15cm
So
e Table 2. Percentage of disease sites covered by current analysis Site
%
Colorectal Pancreas Biliary Duct Sarcoma Other
37 35 6 11 11
60
$
a
3
40
20
0
Fig. 1. Intraoperative applicator (cone) usage by electron beam nominal energy for 2 14 consecutive treatments.
* Clinic@18, Varian Radiation Division, Palo Alto, CA. t Lucite@,Plexiglas@.
Reprint requests to: E. C. McCullough, Ph.D. Accepted for publication 2 1 April 1988. 1041
1042
I. J. Radiation Oncology 0 Biology 0 Physics
October 1988, Volume 15, Number 4 100
100
60
.-5
60
3
g
260
60
5
ii
$
a
3
E
40
.ti
E LL
20
40 20
0
0
4
Cone type
4.5
5
5.5
6
6.5
7
7.5
a
6.5
9
Cone diameter, cm
Fig. 2. Intraoperative applicator (cone) usage by shape/bevel angle for 2 14 consecutive treatments.
Fig. 3. Fractional use for circular intraoperative 2 14 consecutive treatments.
bility that the Mayo Clinic has enjoyed. The circular cones are ideal for a majority of biliary,’ pancreas,394 and colorecta12’5 cases. For pancreatic lesions, flat end or 15 degree beveled end cones are used in most patients. With pelvic IORT 15 or 30 degree beveled cones are used in a majority of patients. Our use of circular cone diameters of 4 to 5.5 cm will increase as we use combined external beam plus IORT approaches for bladder preservation in
patients with early bladder cancer. The elliptical and rectangular cones have been used primarily with retroperitoneal sarcomas (para-aortic or posterior abdominal wall fields), recurrent or primary cervix patients with iliac and/or para-aortic nodal metastases or with advanced colorectal cancers with extrapelvic presentation (e.g., posterior or lateral abdominal wall, or para-aortic involvement).
applicators for
REFERENCES Buskirk, S.J., Gunderson, L.L., Adson, M.A., Martinez, A., May, G.R., McIlrath, D.C., Nagomey, D.M., Edmonson, G.K., Bender, C.E., Martin, J.K.: Analysis of failure following curative irradiation of gallbladder and extrahepatic bile duct carcinoma. Znt.J. Radiat. Oncol. Biol. Phys. 10: 2013-2023, 1984. Gunderson, L.L., Martin, J.K., Beart, R.W., Nagomey, D.M., Fieck, J.M., Wieand, H.S., Martinez, A., O’Connell, M.J., Martenson, J.A., McIlrath, D.C.: External beam and intraoperative electron irradiation for colorectal cancer. Ann. Surg. 207: 52-60, 1988. Gunderson, L.L., Martin, J.K., Earle, J.D., Byer, D.E., Voss, M., Fieck, J.M., Kvols, L.K., Rorie, D.K., Martinez,
A., Nagorney, D.M., O’Connell, M.J., Weber, F.: Intraoperative and external beam irradiation f resection. Mayo pilot experience. Mayo Clin. Proc. 59: 69 l-699, 1984. 4. Gunderson, L.L., Martin, J.K., Kvols, L.K., Nagomey, D.M., Fieck, J.M., Martinez, A., Earle, J.D., McIlrath, D.C.: Intraoperative and external beam irradiation + 5 FU for locally advanced pancreatic cancer. Znt.J. Radiat. Oncol. Biol. Phys. 13: 3 19-329, 1987. 5. Gunderson, L.L., Tepper, J.E., Biggs, P.J., Martin, J.K., Shipley, W.U., Wood, W., Goldson, A., McCullough, EC.: Intraoperative +- external beam irradiation. Curr. Prob. Cancer 7: l-69, 1983.
0360-3016/88 $3.00 + .OU Copyright Q 1988 Pergamon Press plc
??Technical Innovations and Notes
ENERGY AS WELL AS APPLICATOR SIZE AND SHAPE UTILIZED IN OVER 200 INTRAOPERATIVE ELECTRON BEAM PROCEDURES EDWIN C. MCCULLOUGH, PH.D. AND LEONARDL. GUNDERSON,M.D. Division of Radiation Oncology, Mayo Clinic/Foundation, Rochester, MN 55905, U.S.A. treatments were given with 6 and 9 MeV electrons respectively (Fig. 1). The 30 degree beveled circular cones accounted for almost half of those used (Fig. 2). The 0 and 15 degree circular cones were about equal in frequency and each accounted for approximately 20% of the total usage. Elliptical shaped cones had an overall use factor of about 12% (25/2 14) with about equal frequency of flat and beveled ends. The use of rectangular cones has been rare (6/2 14) since the elliptical cones were commissioned. However, we note that rectangular cones should be available for para-aortic IORT. The fractional utilization pattern of circular cones (Fig. 3) indicated that only 20% of utilization (for all three types of circular cones, that is, flat, 15 and 30’ beveled) occurred for cone diameters below 6 cm. Figures 2 and 3 indicate that a minimal set of circular cones for intraoperative electron beam radiation therapy would consist of circular diameters from 6 to 9 cm in 5 mm steps, one set with flat ends and a second set with beveled ends (e.g. at 20’). With this complement of cones, approximately 70% of patients could receive near optimal IORT. Obviously, a complete set of circular cones (ends at 0, 15 and 30 degrees) combined with elliptical and rectangular ones would provide the same flexi-
The Mayo Clinic currently combines external beam photons with intraoperatively administered electron beam boosts (IORT) for locally advanced malignancies for which standard treatment approaches achieve inadequate local control. A linear accelerator* with variable electron energies (6, 9, 12, 15 and 18 MeV) is used in conjunction with a set of methyl methacrylatet applicators (cones) of varying size and shape (Table 1). As a result of inquiries about electron energy as well as cone size and shape utilization, an analysis of these factors has been carried out for 2 14 consecutive IORT fields in 190 patients (see Table 2 regarding anatomic distribution). The majority of treatments were given with electron energies of 12 MeV and greater. Only 2 and 27 (of 2 14)
Table 1. Intraoperative applicator (cone) sizes and shapes in use at Mayo Clinic Shape
Size
Circular 0
4 through 9 cm in 0.5 cm increments 4 through 8.5 cm in 0.5 cm increments 5 through 8.5 cm in 0.5 cm increments
0
::O Elliptical 0
6~ 11,7X 6X 11,7x
2s
Rectangular 0 20”
12,9X 12,9x
12cm
12cm
100
8X9,8X 12,8X 15cm 8~ 12,8X 15cm
So
e Table 2. Percentage of disease sites covered by current analysis Site
%
Colorectal Pancreas Biliary Duct Sarcoma Other
37 35 6 11 11
60
$
a
3
40
20
0
Fig. 1. Intraoperative applicator (cone) usage by electron beam nominal energy for 2 14 consecutive treatments.
* Clinic@18, Varian Radiation Division, Palo Alto, CA. t Lucite@,Plexiglas@.
Reprint requests to: E. C. McCullough, Ph.D. Accepted for publication 2 1 April 1988. 1041
1042
I. J. Radiation Oncology 0 Biology 0 Physics
October 1988, Volume 15, Number 4 100
100
60
.-5
60
3
g
260
60
5
ii
$
a
3
E
40
.ti
E LL
20
40 20
0
0
4
Cone type
4.5
5
5.5
6
6.5
7
7.5
a
6.5
9
Cone diameter, cm
Fig. 2. Intraoperative applicator (cone) usage by shape/bevel angle for 2 14 consecutive treatments.
Fig. 3. Fractional use for circular intraoperative 2 14 consecutive treatments.
bility that the Mayo Clinic has enjoyed. The circular cones are ideal for a majority of biliary,’ pancreas,394 and colorecta12’5 cases. For pancreatic lesions, flat end or 15 degree beveled end cones are used in most patients. With pelvic IORT 15 or 30 degree beveled cones are used in a majority of patients. Our use of circular cone diameters of 4 to 5.5 cm will increase as we use combined external beam plus IORT approaches for bladder preservation in
patients with early bladder cancer. The elliptical and rectangular cones have been used primarily with retroperitoneal sarcomas (para-aortic or posterior abdominal wall fields), recurrent or primary cervix patients with iliac and/or para-aortic nodal metastases or with advanced colorectal cancers with extrapelvic presentation (e.g., posterior or lateral abdominal wall, or para-aortic involvement).
applicators for
REFERENCES Buskirk, S.J., Gunderson, L.L., Adson, M.A., Martinez, A., May, G.R., McIlrath, D.C., Nagomey, D.M., Edmonson, G.K., Bender, C.E., Martin, J.K.: Analysis of failure following curative irradiation of gallbladder and extrahepatic bile duct carcinoma. Znt.J. Radiat. Oncol. Biol. Phys. 10: 2013-2023, 1984. Gunderson, L.L., Martin, J.K., Beart, R.W., Nagomey, D.M., Fieck, J.M., Wieand, H.S., Martinez, A., O’Connell, M.J., Martenson, J.A., McIlrath, D.C.: External beam and intraoperative electron irradiation for colorectal cancer. Ann. Surg. 207: 52-60, 1988. Gunderson, L.L., Martin, J.K., Earle, J.D., Byer, D.E., Voss, M., Fieck, J.M., Kvols, L.K., Rorie, D.K., Martinez,
A., Nagorney, D.M., O’Connell, M.J., Weber, F.: Intraoperative and external beam irradiation f resection. Mayo pilot experience. Mayo Clin. Proc. 59: 69 l-699, 1984. 4. Gunderson, L.L., Martin, J.K., Kvols, L.K., Nagomey, D.M., Fieck, J.M., Martinez, A., Earle, J.D., McIlrath, D.C.: Intraoperative and external beam irradiation + 5 FU for locally advanced pancreatic cancer. Znt.J. Radiat. Oncol. Biol. Phys. 13: 3 19-329, 1987. 5. Gunderson, L.L., Tepper, J.E., Biggs, P.J., Martin, J.K., Shipley, W.U., Wood, W., Goldson, A., McCullough, EC.: Intraoperative +- external beam irradiation. Curr. Prob. Cancer 7: l-69, 1983.