External Treatment Options

Can­cer treat­ment often re­quires a multi-dis­ci­pli­nary ap­proach, which in­cludes chemother­apy and ra­di­a­tion ther­apy. Every­one at Cen­tral Care Can­cer Cen­ter plays an im­por­tant role as an ac­tive team mem­ber. This team-ori­ented ap­proach is the key to en­sur­ing op­ti­mum pa­tient care.

External treatments, like radiation therapy in Missouri and Kansas, are delivered using a machine called a linear accelerator. The treatment beam is only on for a matter of seconds, although it is not measured by time. The linear accelerator runs on electricity, so when the machine is turned off there is no radiation in the treatment room.

Pre­cise pa­tient po­si­tion­ing and real-time tumor mon­i­tor­ing are vital to ac­cu­rate treat­ment of de­fined areas while spar­ing sur­round­ing nor­mal tis­sues. The ad­vance­ment of con­for­mal ra­dio­ther­a­pies has been sup­ple­mented by im­age-guided ra­dio­ther­apy, or IGRT, en­abling clin­i­cians to com­pen­sate for the geo­met­ric un­cer­tain­ties in­her­ent in the treat­ment de­liv­ery process. Tu­mors can move, be­cause of breath­ing and other nat­u­rally oc­cur­ring processes within the body. IGRT al­lows physi­cians to lo­cate and track the tumor just prior to and dur­ing ra­di­a­tion treat­ment to en­hance the pre­ci­sion of the ra­di­a­tion beam and pro­tect healthy tis­sues, ul­ti­mately re­duc­ing side ef­fects and im­prov­ing out­comes.

Cen­tral Care Can­cer Cen­ter uti­lizes a di­verse set of imag­ing tools, such as kV and MV imag­ing with our elec­tronic por­tal im­ager, Cone Beam CT (CBCT), flu­o­roscopy, and res­pi­ra­tory gat­ing tech­nol­ogy. These tools make it pos­si­ble to deal with in­ter-frac­tion mo­tion (i.e., changes in tar­get po­si­tion due to setup error or nat­u­rally-oc­cur­ring changes in organ po­si­tion over time) and in­tra-frac­tion mo­tion (i.e., organ mo­tion dur­ing treat­ment, usu­ally due to res­pi­ra­tion or other phys­i­o­log­i­cal processes). Our ra­di­a­tion on­col­o­gists can then make im­me­di­ate tech­ni­cal ad­just­ments when a tumor moves out­side of a planned treat­ment range. As a re­sult, the ra­di­a­tion treat­ment is tar­geted pre­cisely to the tumor, help­ing to limit ra­di­a­tion ex­po­sure to healthy tis­sue and re­duce com­mon ra­di­a­tion side ef­fects.

The physi­cians can choose from a mul­ti­tude imag­ing tools for pa­tient repo­si­tion­ing based on bony anatomy, im­planted or ex­ter­nal fidu­cial mark­ers, soft tis­sue struc­tures, and/or res­pi­ra­tory gat­ing ver­i­fi­ca­tion. Im­ages are usu­ally ac­quired just after the pa­tient has been po­si­tioned for treat­ment, and then spe­cial match­ing soft­ware is used to com­pare the im­ages to ref­er­ence im­ages from the treat­ment plan. The sys­tem then cal­cu­lates a “shift” and sends in­struc­tions to the treat­ment couch, which moves to bring the tar­geted tumor into pre­cise align­ment for treat­ment. Pa­tient po­si­tion­ing is then ver­i­fied prior to treat­ment de­liv­ery. For some cases, tar­get po­si­tion­ing may occur dur­ing the treat­ment de­liv­ery as well.

Cen­tral Care Can­cer Cen­ter has de­vel­oped spe­cific pro­to­cols for IGRT based on na­tion­ally pub­lished guide­lines and ver­i­fied using a rig­or­ous in­ter­nal qual­ity as­sur­ance and peer re­view pro­gram. IGRT al­lows the treat­ment team to ob­tain high-res­o­lu­tion, three-di­men­sional im­ages to pin­point tumor sites, ad­just pa­tient po­si­tion­ing when nec­es­sary, and com­plete a treat­ment—all within the stan­dard treat­ment time slot of 15-20 min­utes. IGRT en­ables pin­point ac­cu­racy of treat­ment de­liv­ery by en­sur­ing re­pro­ducible, sta­ble and ac­cu­rate pa­tient po­si­tion­ing.

The pic­ture you ini­tially see is of a Var­ian Tril­ogy ma­chine with on-board imag­ing (OBI) and the setup CBCT im­ages of a pelvis field. The video shows the process of using the ac­quired CBCT and uti­liz­ing the ro­botic couch to re­motely po­si­tion a pa­tient for treat­ment. OBI with CBCT is just one of the many IGRT op­tions avail­able at Cen­tral Care Can­cer Cen­ter fa­cil­i­ties.

In­ten­sity-mod­u­lated ra­di­a­tion ther­apy (IMRT) is an ad­vanced treat­ment method that uses com­puter-con­trolled lin­ear ac­cel­er­a­tors to de­liver high doses of ra­di­a­tion di­rectly to can­cer cells in a very tar­geted way, much more pre­cisely than is pos­si­ble with con­ven­tional ra­dio­ther­apy. IMRT en­ables an on­col­ogy team to di­rect and nar­rowly con­cen­trate po­tent doses of high-en­ergy X rays at a pa­tient’s tumor while min­i­miz­ing com­pli­ca­tions to sur­round­ing healthy tis­sue.

IMRT uses mul­ti­ple small ra­di­a­tion beams of vary­ing in­ten­si­ties to pre­cisely ir­ra­di­ate a tumor. This method in­volves vary­ing (or mod­u­lat­ing) the in­ten­sity of the ra­di­a­tion beam while si­mul­ta­ne­ously chang­ing the geo­met­ric pro­file of the de­liv­ery area so that the shape of the re­sult­ing dose de­liv­ery is tightly matched to the shape of the tumor. IMRT tar­gets a tumor with in­ten­sity-mod­u­lated beams de­liv­ered from mul­ti­ple an­gles. The area where the ra­di­a­tion beams in­ter­sect cre­ates a finely sculpted ra­di­a­tion cloud that en­velops and has the same shape as the tumor. The goal of IMRT is to con­form the ra­di­a­tion dose to avoid or re­duce ex­po­sure of healthy tis­sue and limit the side ef­fects of treat­ment.

Treat­ment plan­ning for IMRT is more com­plex than for con­ven­tional ra­di­a­tion ther­apy. The IMRT process starts with plan­ning im­ages, for ex­am­ple, com­puted to­mog­ra­phy (CT), mag­netic res­o­nance (MR) and/or positron emis­sion to­mog­ra­phy (PET) im­ages, of the pa­tient’s tumor and sur­round­ing anatomy. These im­ages are con­verted into a cus­tom three-di­men­sional model of the pa­tient’s in­ter­nal anatomy. A so­phis­ti­cated com­puter pro­gram is used to de­ter­mine the dose in­ten­sity pat­tern that will best con­form to the tumor shape, cre­at­ing a treat­ment plan based on tumor size, shape, and lo­ca­tion within the body, com­bined with the doc­tor’s dose pre­scrip­tion. Typ­i­cally, com­bi­na­tions of mul­ti­ple in­ten­sity-mod­u­lated fields com­ing from dif­fer­ent beam di­rec­tions pro­duce a cus­tom tai­lored ra­di­a­tion plan that max­i­mizes tumor dose while also min­i­miz­ing the dose to ad­ja­cent nor­mal tis­sues.

The equip­ment used to de­liver ra­di­a­tion treat­ment is called a med­ical lin­ear ac­cel­er­a­tor, which is equipped with a spe­cial beam-shap­ing de­vice called a multi-leaf col­li­ma­tor (MLCs). IMRT uti­lizes con­for­mal MLCs that can turn on or off dy­nam­i­cally chang­ing the field dur­ing dose de­liv­ery. The lin­ear ac­cel­er­a­tor ro­tates around the pa­tient to send beams from mul­ti­ple an­gles in order to give the tumor a high dose of ra­di­a­tion while pre­serv­ing im­por­tant healthy tis­sues.

The num­ber of IMRT treat­ments is typ­i­cally more than con­ven­tional ra­di­a­tion ther­apy be­cause of the highly con­for­mal beam which al­lows a higher dose to be de­liv­ered safely. Ac­tual treat­ment time for each ses­sion may be slightly longer than with con­ven­tional ra­di­a­tion ther­apy be­cause of the com­plex­ity of the treat­ment and the ad­di­tional qual­ity as­sur­ance checks and pre­ci­sion tar­get­ing.
His­tor­i­cally, the max­i­mum ra­di­a­tion dose that could be given to a tumor site has been re­stricted by the tol­er­ance and sen­si­tiv­ity of the sur­round­ing nearby healthy tis­sues. IMRT de­liv­ers higher doses of ra­di­a­tion di­rectly to tu­mors and can­cer cells, while sur­round­ing or­gans and tis­sues are pro­tected. The level of nor­mal tis­sue spar­ing achieved with IMRT is sig­nif­i­cant, re­sult­ing in fewer com­pli­ca­tions and side ef­fects.

IMRT of­fers very high-res­o­lu­tion de­liv­ery, giv­ing an on­col­ogy team the abil­ity to con­form the dose tightly to a small or ir­reg­u­larly shaped tar­get. Pre­ci­sion tar­get­ing is es­pe­cially im­por­tant when de­liv­er­ing dose around small or oddly shaped struc­tures such as the optic nerves or sali­vary glands. IMRT can more ef­fec­tively shape the dose around such crit­i­cal struc­tures, se­verely lim­it­ing or even elim­i­nat­ing un­nec­es­sary ex­po­sures to ra­di­a­tion dose.

IMRT dif­fers from con­ven­tional ra­di­a­tion ther­apy by em­ploy­ing com­plex soft­ware to plan a ther­a­peu­tic dose of ra­di­a­tion based on tumor di­men­sions and lo­ca­tion. IMRT de­liv­ers ra­di­a­tion in sculpted doses that ex­actly match the 3D shape of the tumor, ad­just­ing the in­ten­sity of the ra­di­a­tion beams across the tumor area with un­par­al­leled ac­cu­racy. Be­cause of its greater de­gree of ac­cu­racy, IMRT may be a treat­ment op­tion for re­cur­rent or per­sis­tent tu­mors after con­ven­tional doses have been de­liv­ered.
Be­cause the ratio of nor­mal tis­sue dose to tumor dose is re­duced to a min­i­mum with the IMRT ap­proach, higher and more ef­fec­tive ra­di­a­tion doses can safely be de­liv­ered to tu­mors with fewer side ef­fects com­pared with con­ven­tional ra­dio­ther­apy tech­niques. IMRT also has the po­ten­tial to re­duce treat­ment tox­i­c­ity, even when doses are not in­creased. The end re­sult is bet­ter tumor con­trol, less dam­age to healthy tis­sues and struc­tures in the treat­ment area, and a bet­ter qual­ity of life for the pa­tient.

The ini­tial pic­ture seen is a de­pic­tion of an IMRT plan of a pelvis con­structed using our Eclipse Treat­ment Plan­ning soft­ware. Eclipse soft­ware and IMRT tech­nol­ogy are two tools used by Cen­tral Care Can­cer Cen­ters to op­ti­mize your treat­ment out­comes.

Certain tumors are treated using Rapid Arc technology. The radiation is delivered in a circular pattern as the linear accelerator rotates around the patient’s body.

Respiratory gating allows treatment to be given in sync with a patient’s breathing pattern. The radiation is delivered in small portions during a chosen portion of a normal breathing cycle. This allows maximum dose to a tumor volume that may be mobile during normal breathing.

SRT is used to de­liver ex­tremely high doses of ra­di­a­tion in a short amount of time. A dis­ease must meet very spe­cific cri­te­ria re­lated to tumor size, type, and lo­ca­tion, and a pa­tient must be able to fol­low care­ful in­struc­tions re­lated to po­si­tion­ing.

Stereotactic treatments delivered to areas within the body but not the head.

Stereotactic treatments delivered usually to a head or spine region, consisting of one very large dose of radiation delivered in one treatment.